JP2008176281A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device which has excellent color reproducibility with wide viewing angle and in which color shift is not observed even as observed in an oblique direction in a black state. <P>SOLUTION: The liquid crystal display device comprises at least a liquid crystal cell LC, and a polarizing plates (P1, P2) disposed on at least one side of the outsides of the liquid crystal cell, wherein the liquid crystal cell has a pair of substrates (1, 3) which face each other and one of which is provided with an electrode and a liquid crystal layer (5) sandwiched between the pair of substrates (1, 3), and includes at least three pixel regions, wherein a color filter showing wavelength selectivity in transmissivity is disposed on each of the three pixel regions. In the liquid crystal display device, when the thicknesses of the liquid crystal layers corresponding to a color filter showing a maximum transmissivity at a main wavelength λ<SB>1</SB>, a color filter showing a maximum transmissivity at a main wavelength λ<SB>2</SB>, and a color filter showing a maximum transmissivity at a main wavelength λ<SB>3</SB>, provided that λ<SB>1</SB>, λ<SB>2</SB>, and λ<SB>3</SB>(unit: nm) are in an order from the smaller one, are d<SB>1</SB>, d<SB>2</SB>and d<SB>3</SB>(unit: nm) respectively, relation (1) is satisfied: d<SB>1</SB><d<SB>2</SB>(1). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device having wide viewing angle characteristics and excellent color reproducibility.

  Liquid crystal display elements (also referred to as liquid crystal display panels), electroluminescence elements (separated into organic and inorganic types depending on the fluorescent material used, hereinafter referred to as EL elements), field emission devices (hereinafter referred to as FED elements), electrophoresis A display device using an element or the like displays an image without providing a space (vacuum housing) for two-dimensionally scanning an electron beam on the back side of a display screen like a cathode ray tube (CRT). . Therefore, these display devices are characterized by being thinner and lighter and having lower power consumption than a cathode ray tube. These display devices are sometimes referred to as flat panel displays because of their appearance characteristics.

  A display device using a liquid crystal display element, an EL element, a field emission element, or the like is a display using a cathode ray tube in various applications such as notebook computers, OA devices such as personal computer monitors, portable terminals, and televisions because of the above-described advantages over the cathode ray tube. It is becoming widespread instead of devices. Technological innovations such as viewing angle characteristics of liquid crystal display elements and EL elements and image quality improvement such as expansion of the display color reproducibility area are behind the progress of replacement of CRTs with flat panel displays. Recently, with the widespread use of multimedia and the Internet, there has been an improvement in video display performance. Furthermore, there are some fields that cannot be realized with CRT, such as electronic paper, large public, and advertising information displays.

A liquid crystal display device usually includes a liquid crystal cell, a drive circuit that sends a display signal voltage to the liquid crystal cell, a backlight (back light source), and a signal control system that sends an input image signal to the drive circuit. .
A liquid crystal cell usually comprises liquid crystal molecules, two substrates for enclosing and sandwiching the liquid crystal molecules, and an electrode layer for applying a voltage to the liquid crystal molecules, and a polarizing plate is disposed on the outer side thereof. The polarizing plate is usually composed of a protective film and a polarizing film, and is obtained by dyeing a polarizing film made of a polyvinyl alcohol film with iodine, stretching, and laminating both surfaces with a protective film. In the transmissive liquid crystal display device, the polarizing plate is attached to both sides of the liquid crystal cell, and one or more optical compensation sheets may be disposed. In a reflective liquid crystal display device, usually, a reflector, a liquid crystal cell, one or more optical compensation sheets, and a polarizing plate are arranged in this order. The liquid crystal cell performs ON-OFF display depending on the alignment state of liquid crystal molecules, and can be applied to any of a transmission type, a reflection type, and a semi-transmission type.

When an optical compensation sheet whose optical properties are designed to an optimum value for each wavelength of light is used, a liquid crystal display device having a wide visual field characteristic with little color change can be provided. In these conventional liquid crystal display devices, attempts have been made to improve the color change by controlling the wavelength dispersion of retardation of the optical compensation film (Patent Document 1). It has also been attempted to balance display colors by changing the in-plane retardation value (Re) of each color of the color filter for each color (Patent Document 2).
Japanese Patent Laid-Open No. 2002-221622 Japanese Patent Laid-Open No. 5-196931

However, the conventional liquid crystal display device cannot be improved at all wavelengths, and coloration when observed from an oblique direction cannot be sufficiently improved.
Accordingly, an object of the present invention is to provide a liquid crystal display device having excellent color reproducibility over a wide viewing angle.
Further, in the conventional liquid crystal display device, the so-called color shift problem of coloring blue or red is not solved when observing obliquely during black display.
Accordingly, it is an object of the present invention to provide a liquid crystal display device in which color shift is not observed or color shift is reduced even when observed from an oblique direction during black display.

Means for solving the problems are as follows.
[1] It has at least a liquid crystal cell and a polarizing plate (first polarizing plate) disposed on at least one of the outside of the liquid crystal cell, and the liquid crystal cell is disposed so as to face at least one electrode. A color filter that includes a pair of substrates and a liquid crystal layer sandwiched between the substrates, includes at least three pixel regions, and has wavelength selectivity for transmittance on the three pixel regions. Λ ₁ , λ ₂ , and λ ₃ (unit: nm) in ascending order of the main wavelengths taking the maximum transmittance of the color filter provided in each pixel region, the liquid crystal layer in each of these pixel regions A liquid crystal display device satisfying the following formula (1), where d ₁ , d ₂ , and d ₃ (unit: nm) are:
Equation _{(1): d 2 <d} 3.
[2] The liquid crystal display device according to [1], which further satisfies the following formula (2):
Equation _{(2): d 1 <d} 2 <d 3.
[3] Of the retardation (Rth) in the thickness direction of the color filters arranged on the three picture element regions, the Rths of the color filters arranged in at least two picture element regions are different from each other. The liquid crystal display device according to [1] or [2].
[4] The liquid crystal display device according to any one of [1] to [3], wherein the color filter satisfies the following formulas (I) and (II):
(I) | Re (630) | ≦ 10 and | Rth (630) | ≦ 40
(II) | Re (400) −Re (700) | ≦ 10 and | Rth (400) −Rth (700) | ≦ 35
In the above formulas (I) and (II), Re (λ) represents the in-plane retardation value (nm) at the wavelength λnm, and Rth (λ) represents the retardation value (nm) in the thickness direction at the wavelength λnm. To express.

[5] A first optically anisotropic layer satisfying the following formulas (III) and (IV), and a second optically anisotropic layer having at least one optical axis in the plane, The liquid crystal display device according to any one of [1] to [4]:
Formula (III) 0 nm <Rth (550) ≦ 300 nm
Formula (IV) Rth (550) / Re (550)> 10.
[6] The liquid crystal display device according to [5], wherein the first optically anisotropic layer satisfies the following formulas (V) to (VII):
Formula (V) Rth (450) / Rth (550) ≧ 1
Formula (VI) Rth (630) / Rth (550) ≦ 1
Formula (VII) −30 nm ≦ Rth (630) −Rth (450) ≦ 0 nm.
[7] The liquid crystal display device of [5] or [6], wherein the second optically anisotropic layer satisfies the following formulas (VIII) and (IX):
Formula (VIII) 55 nm ≦ Re (550) ≦ 315 nm
Formula (IX) 0 nm ≦ Rth (550) ≦ 275 nm.
[8] An optically anisotropic layer A is provided between the first polarizing plate and the liquid crystal cell, the optically anisotropic layer A satisfies the following formulas (XV) and (VXI), and [1] to [4], wherein when the slow axis of the optically anisotropic layer A is projected on the same plane as the absorption axis of the first polarizing plate, the projection axis is parallel to the absorption axis. ] Liquid crystal display device:
(XV) 30 nm ≦ Re (550) ≦ 80 nm
(XVI) 75 nm ≦ Rth (550) ≦ 155 nm.
[9] A second polarizing plate that has a second polarizing plate that is disposed with the liquid crystal cell sandwiched with the first polarizing plate and that has an absorption axis perpendicular to the absorption axis of the first polarizing plate. An optically anisotropic layer B is provided between the plate and the liquid crystal cell, the optically anisotropic layer B satisfies the formulas (XV) and (XVI), and the optically anisotropic layer B [8] The liquid crystal display device according to [8], wherein when the slow axis is projected on the same plane as the absorption axis of the second polarizing plate, the projection axis is parallel to the absorption axis.
[10] The retardation Rth (550) in the thickness direction of each of the optically anisotropic layers A and B at a wavelength of 550 nm and Δn (550) × d of the liquid crystal layer satisfy the relationship of the following formula (XVII): [9] A liquid crystal display device characterized by:
(XVII) 0.7 ≦ (2 × Rth (550)) / Δn (550) × d ≦ 1.3
Here, Δn (550) is the refractive index anisotropy in the thickness direction of the liquid crystal layer at 550 nm, and d is the average thickness (nm) of the liquid crystal layer.

[11] At least one of the optically anisotropic layers contains at least one polymer and at least one additive, and at least one additive is a liquid crystalline compound [5] ] The liquid crystal display device according to any one of [10].
[12] The composition according to [11], wherein 0.1 to 30% by mass of at least one liquid crystal compound is contained, and the mass ratio of the liquid crystal compound to all additives is 40 to 100% by mass. Liquid crystal display device.
[13] It is characterized in that it contains 0.1 to 30% by mass of two or more types of liquid crystalline compounds, and the mass ratio of the two or more types of liquid crystalline compounds to all additives is 50 to 100% by mass. The liquid crystal display device according to [11] or [12].

（式中、Ｌ¹及びＬ²は各々独立に単結合又は二価の連結基を表す。Ａ¹及びＡ²は各々独立に、−Ｏ−、−ＮＲ−（Ｒは水素原子又は置換基を表す。）、−Ｓ−及び−ＣＯ−からなる群から選ばれる基を表す。Ｒ¹、Ｒ²、及びＲ³は各々独立に置換基を表す。
Ｘは６族、５族又は４族原子を表す。ｎは０から２までの整数を表す。）
一般式（ａ）：Ａｒ¹−Ｌ¹²−Ｘ−Ｌ¹³−Ａｒ²
上記一般式（ａ）において、Ａｒ¹及びＡｒ²はそれぞれ独立に、芳香族基であり；Ｌ¹²及びＬ¹³はそれぞれ独立に、−Ｏ−ＣＯ−又は−ＣＯ−Ｏ−基であり；Ｘは、１，４−シクロへキシレン基、ビニレン基又はエチニレン基である。 [14] The liquid crystal compound comprises at least one compound represented by the following formula (A) and a rod-shaped compound represented by the following formula (a): [11] to [13] Any liquid crystal display device.

(In the formula, L ¹ and L ² each independently represent a single bond or a divalent linking group. A ¹ and A ² each independently represent —O—, —NR— (R represents a hydrogen atom or a substituent). Represents a group selected from the group consisting of —S— and —CO—, and R ¹ , R ² , and R ³ each independently represents a substituent.
X represents a group 6, 5 or 4 atom. n represents an integer of 0 to 2. )
Formula (a): Ar ¹ -L ¹² -XL ¹³ -Ar ²
In the general formula (a), Ar ¹ and Ar ² are each independently an aromatic group; L ¹² and L ¹³ are each independently an —O—CO— or —CO—O— group; X Is a 1,4-cyclohexylene group, a vinylene group or an ethynylene group.

[15] The liquid crystal display device according to any one of [5] to [14], wherein at least one of the optically anisotropic layers is made of a norbornene-based polymer film.
[16] The liquid crystal display device according to any one of [5] to [14], wherein at least one of the optically anisotropic layers is made of a cellulose acylate film.
[17] The liquid crystal display device according to [16], wherein the acyl substituent of cellulose acylate contained as a main component in the cellulose acylate film is at least one selected from acetyl, propionyl and butyryl.
[18] The liquid crystal display device according to any one of [5] to [17], wherein at least one of the optically anisotropic layers contains at least one Rth enhancer.
[19] The liquid crystal display device according to [18], wherein the Rth enhancer contains at least one compound having an absorption maximum at 250 nm to 380 nm.

（式中、Ｘ¹は、単結合、−ＮＲ⁴−、−Ｏ−又はＳ−であり；Ｘ²は、単結合、−ＮＲ⁵−、−Ｏ−又はＳ−であり；Ｘ³は、単結合、−ＮＲ⁶−、−Ｏ−又はＳ−である。また、Ｒ¹、Ｒ²、及びＲ³は、それぞれ独立に、アルキル基、アルケニル基、芳香族環基又は複素環基であり；Ｒ⁴、Ｒ⁵及びＲ⁶は、それぞれ独立に、水素原子、アルキル基、アルケニル基、アリール基又は複素環基である。） [20] The liquid crystal display device according to [18] or [19], wherein the Rth enhancer contains at least one compound represented by the following formula (I).

(Wherein, X ¹ is a single bond, -NR ⁴ -, - O-or a S-; X ² represents a single bond, -NR ⁵ -, - O-or a S-; X ³ is A single bond, —NR ⁶ —, —O—, or S—, and R ¹ , R ² , and R ³ are each independently an alkyl group, an alkenyl group, an aromatic ring group, or a heterocyclic group. R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group.

[21] The liquid crystal display device according to [20], comprising 0.1 to 30% by mass of at least one compound represented by the formula (I).
[22] The liquid crystal display device according to any one of [5] to [21], wherein the optically anisotropic layer has a thickness of 30 to 200 μm.
[23] A parallel alignment type ECB mode in which the alignment of liquid crystal molecules changes in a direction perpendicular to the substrate surface by application of an electric field, and the transmittance of the liquid crystal layer decreases. [1] to [22] Any one of the liquid crystal display devices.
[24] The liquid crystal display device according to any one of [1] to [22], which is in a bend alignment display mode.
[25] The liquid crystal display device according to any one of [1] to [22], which is in a TN display mode.
[26] The liquid crystal display device according to any one of [1] to [22], which is in a VA display mode.

  According to the present invention, a liquid crystal display device having excellent color reproducibility in a wide viewing angle can be provided. In addition, according to the present invention, it is possible to provide a liquid crystal display device in which color shift is not observed or color shift is reduced even when observed from an oblique direction during black display.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is described in detail below. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
First, terms used in this specification will be described.
(Retardation, Re, Rth)
In the present specification, Re (λ) and Rth (λ) represent in-plane retardation (nm) and retardation in the thickness direction (nm) at wavelength λ, respectively. Re (λ) is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments).
When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (λ) is calculated by the following method.
Rth (λ) is Re (λ), with the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotation axis) (if there is no slow axis, any in-plane film The light of wavelength λ nm is incident from each of the inclined directions in steps of 10 degrees from the normal direction to 50 degrees on one side with respect to the film normal direction (with the direction of the rotation axis as the rotation axis). KOBRA 21ADH or WR is calculated based on the measured retardation value, the assumed value of the average refractive index, and the input film thickness value.
In the above case, in the case of a film having a direction in which the retardation value is zero at a certain tilt angle with the in-plane slow axis from the normal direction as the rotation axis, retardation at a tilt angle larger than the tilt angle. The value is calculated by KOBRA 21ADH or WR after changing its sign to negative.
In addition, the retardation value is measured from two inclined directions, with the slow axis as the tilt axis (rotation axis) (when there is no slow axis, the arbitrary direction in the film plane is the rotation axis), Rth can also be calculated from the following formula (I) and formula (II) based on the value, the assumed value of the average refractive index, and the input film thickness value.

注記：
上記のＲｅ（θ）は法線方向から角度θ傾斜した方向におけるレターデーション値をあらわす。また、式中、ｎｘは面内における遅相軸方向の屈折率を表し、ｎｙは面内においてｎｘに直交する方向の屈折率を表し、ｎｚはｎｘ及びｎｙに直交する方向の屈折率を表す。ｄは膜厚を表す。

Note:
The above Re (θ) represents a retardation value in a direction inclined by an angle θ from the normal direction. In the formula, nx represents the refractive index in the slow axis direction in the plane, ny represents the refractive index in the direction orthogonal to nx in the plane, and nz represents the refractive index in the direction orthogonal to nx and ny. . d represents a film thickness.

In the case where the film to be measured cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film having no so-called optical axis, Rth (λ) is calculated by the following method.
Rth (λ) is the above-mentioned Re (λ), and the in-plane slow axis (determined by KOBRA 21ADH or WR) is the tilt axis (rotation axis) from −50 degrees to +50 degrees with respect to the film normal direction. The light of wavelength λ nm is incident from each inclined direction in 10 degree steps and measured at 11 points, and KOBRA 21ADH or WR is calculated.
In the above measurement, the assumed value of the average refractive index may be a value in a polymer handbook (John Wiley & Sons, Inc.) or a catalog of various optical films. Those whose average refractive index is not known can be measured with an Abbe refractometer. Examples of the average refractive index values of main optical films are given below:
Cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).
The KOBRA 21ADH or WR calculates nx, ny, and nz by inputting the assumed value of the average refractive index and the film thickness. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

In the present specification, regarding the angle, “+” means the counterclockwise direction, and “−” means the clockwise direction. Further, when the upper direction of the liquid crystal display device is 12 o'clock and the lower direction is 6 o'clock, the absolute value of 0 ° in the angular direction means the 3 o'clock direction (right direction on the screen). Further, the “slow axis” means a direction in which the refractive index is maximized. The “visible light region” means 380 nm to 780 nm. Further, the measurement wavelength of the refractive index is a value at λ = 550 nm in the visible light region unless otherwise specified.
Also, regarding the angle between each axis and direction, “parallel”, “vertical”, “45 °”, etc. means “approximately parallel”, “approximately vertical”, “approximately 45 °”, and is strictly is not. Some deviation is allowed within the range to achieve each purpose. For example, “parallel” means that the crossing angle is approximately 0 °, and is −10 ° to 10 °, preferably −5 ° to 5 °, more preferably −3 ° to 3 °. “Vertical” means that the crossing angle is approximately 90 °, and is 80 ° to 100 °, preferably 85 ° to 95 °, more preferably 87 ° to 93 °. “45 °” means that the crossing angle is approximately 45 °, and is 35 ° to 55 °, preferably 40 ° to 50 °, more preferably 42 ° to 48 °.

  In this specification, “polarizing film (polarizing film)” and “polarizing film” are distinguished from each other. However, the “polarizing film” has a transparent protective film for protecting the polarizing film on at least one surface of the “polarizing film”. It shall mean a laminate.

In the present invention, λ ₁ , λ ₂ , and λ ₃ (unit: nm) are set in ascending order of the main wavelengths taking the maximum transmittance of the color filter provided in each pixel region, and the liquid crystal in each of these pixel regions The present invention relates to a liquid crystal display device that satisfies the following formula (1) when the thicknesses of the layers are d ₁ , d ₂ , and d ₃ (unit: nm) in this order.
Equation _{(1): d 2 <d} 3.
That is, the present invention improves the problem of coloring during black display, so-called color shift, by making the thickness of the liquid crystal layer of the liquid crystal cell different for each picture element region.
Furthermore, in the invention, it is more preferable to satisfy the following formula (2).
Equation _{(2): d 1 <d} 2 <d 3.

Hereinafter, the present invention will be described in detail.
If an optical compensation film whose optical properties are designed to an optimum value for each wavelength of light can be used, a liquid crystal display device having a wide field of view with little color change can be provided. It may be industrially difficult to produce a film. In the present invention, the conventional optical compensation film is used as it is, and the retardation for each pixel region of the liquid crystal layer of the liquid crystal cell is designed in accordance with the retardation wavelength dependency of the conventional optical compensation film.
In particular, the inventors of the present invention, in view of the fact that in many of the current optical compensation films, the in-plane retardation is larger when the wavelength of light is shorter, the thickness of the liquid crystal layer for each picture element It has been found that a favorable effect can be obtained when the relationship of formula (1) is established. In particular, the picture element region of the liquid crystal display device is divided into at least three picture elements (for example, three picture elements of R, G, and B), and the thickness of the liquid crystal layer of each picture element adjusts the thickness of the color filter. Therefore, it is possible to control independently.

Embodiments in which the present invention is applied to an ECB mode liquid crystal display device will be described below with reference to the drawings.
(ECB mode type liquid crystal display)
The ECB mode liquid crystal display device shown in FIG. 1 includes a liquid crystal cell LC (1 to 5) and a pair of an upper polarizing plate P1 and a lower polarizing plate P2 which are disposed with the liquid crystal cell LC interposed therebetween.
The rubbing direction 2 of the upper substrate 1 of the liquid crystal cell LC and the rubbing direction 4 of the lower substrate 3 are set in parallel, and the liquid crystal layer has a parallel alignment without a twist structure. The upper substrate 1 and the lower substrate 3 each have an alignment film (not shown) and an electrode layer (not shown). The alignment film has a function of aligning the liquid crystalline molecules 5. The electrode layer has a function of applying a voltage to the liquid crystalline molecules 5. The electrode layer is usually made of transparent indium tin oxide (ITO).

  As an example of a parallel mode liquid crystal layer, a liquid crystal having a dielectric anisotropy Δε of about +8.5 and a refractive index anisotropy Δn = 0.0854 (589 nm, 20 ° C.) between upper and lower substrates (for example, Merck) And a liquid crystal layer made of MLC-9100). The thickness d of the liquid crystal layer can be set to about 3.5 μm. Here, the brightness at the time of white display changes depending on the magnitude of the product Δn · d of the thickness d and the refractive index anisotropy Δn. For this reason, in order to obtain the maximum brightness, it is preferable to set it in the range of 0.2 to 0.4 μm.

  Although the detailed structure is not shown in FIG. 1, the liquid crystal cell LC includes three picture element regions, and the thicknesses of the liquid crystal layers in the respective picture element regions are different from each other. A method for changing the thickness of the liquid crystal layer between the pixel regions is not particularly limited. For example, each layer formed on the opposite surface of the liquid crystal cell, for example, any one or two or more layers such as an alignment layer, an electrode layer, an optical anisotropic layer, a color filter layer, etc., depending on each pixel region By changing the thickness, the thickness of the liquid crystal layer in each picture element region can be different from each other. In particular, it is preferable to change the thickness of the liquid crystal layer by changing the thickness of the color filter layer for each pixel region. More specifically, for example, RGB color filters having different R, G, and B layer thicknesses are formed on the opposing surface of the substrate (1 or 3), and the thickness of the liquid crystal layer in each pixel region Are preferably different. In addition, the substrate 1 or 3 may be a substrate having a plurality of regions having different thicknesses, and the liquid crystal layers at positions corresponding to the respective pixel regions may have different thicknesses. Further, by changing the thickness of other layers formed on the inner surface of the substrate, for example, the top coat film, for each position corresponding to the color of each pixel region, the above formula (1), preferably the above You may produce the liquid crystal cell which satisfies Formula (2).

  In FIG. 1, the upper polarizing plate P1 disposed outside the liquid crystal cell is an elliptically polarized light having a polarizing film 8a, protective films 6a and 10a disposed on the surface of the polarizing film 8a, and an optically anisotropic layer 12a. It is a board. Similarly, the lower polarizing plate P2 disposed outside the liquid crystal cell is an elliptically polarizing plate having a polarizing film 8b, protective films 6b and 10b disposed on the surface of the polarizing film 8b, and an optically anisotropic layer 12b. It is. The absorption axes 9a and 9b of the polarizing plate intersect the liquid crystal cell alignment direction (rubbing directions 2 and 4) approximately 45 °, and the crossing angle of the upper and lower polarizing plate absorption axes 9a and 9b is a crossed Nicol of approximately 90 °. The optically anisotropic layers 12a and 12b compensate for retardation remaining in the liquid crystal layer during black display, and contribute to improvement of contrast. The optically anisotropic layers 12a and 12b can be formed from, for example, a composition containing a liquid crystal compound. Especially, it is preferable to form from the composition containing a disk shaped liquid crystalline compound. For example, a composition containing a discotic liquid crystalline compound is prepared as a coating solution, the coating solution is applied to a rubbing treatment surface having a rubbing axis in the directions of 11a and 11b, and the molecules of the discotic compound are rubbed with the rubbing shaft 11a and It can be produced by aligning according to 11b and fixing in the aligned state. In FIG. 1, the protective films 10a and 10b also serve as supports for the optically anisotropic layers 12a and 12b. Of course, you may arrange | position the optical compensation sheet | seat which has an optically anisotropic layer and the support body which consists of a polymer film etc. separately from a polarizing plate.

Consider a case where light enters from a backlight (not shown) arranged outside the lower polarizing plate P2. In a non-driving state in which a driving voltage is not applied to the respective transparent electrodes (not shown) of the liquid crystal cell substrates 1 and 3, the liquid crystal molecules 5 in the liquid crystal layer are aligned approximately parallel to the surfaces of the substrates 1 and 3. ing. The light having a predetermined polarization state by the polarizing film 8b changes the polarization state by the birefringence effect of the liquid crystalline molecules 5, and as a result, passes through the polarizing film 8a. At this time, the value of Δn · d of the liquid crystal layer is set within the above range so that the transmitted light is maximized. On the other hand, in a driving state in which a driving voltage is applied to a transparent electrode (not shown), the liquid crystalline molecules 5 try to align perpendicularly to the surfaces of the substrates 1 and 3 depending on the magnitude of the applied voltage. However, although the thickness near the center between the substrates is substantially perpendicular to the substrate surface, it is oriented in a parallel direction near the substrate interface, and is continuously inclined toward the center thickness. In such a state, it is difficult to obtain a complete black display. In addition, the average orientation of the tilted liquid crystal molecules in the vicinity of the substrate interface changes depending on the angle to be observed, and the viewing angle dependency in which the transmittance and brightness change depending on the viewing angle occurs. Therefore, in the liquid crystal display device of FIG. 1, the optically anisotropic layers 12a and 12b are arranged to compensate for the residual phase difference of the liquid crystal layer in the vicinity of the substrate interface, thereby obtaining a complete black display and improving the front contrast ratio. ing. Furthermore, in the liquid crystal display device of FIG. 1, since the thickness corresponding to each pixel region of the liquid crystal cell LC has a difference, the formula (1) (preferably the formula (2)) is satisfied. Not only B light incident from an oblique direction but also R light and B light have reduced transmittance during black display, no coloring, and color reproducibility is further improved.
Further, as described in Patent Document 1 described above, the viewing angle characteristics may be further improved by disposing an optical film that compensates for a liquid crystal layer that is continuously inclined and aligned.

  In addition, since the liquid crystal molecules 5 are tilted at the time of halftone display, the magnitude of birefringence of the liquid crystal molecules 5 when viewed from an oblique direction differs between the tilt direction and the opposite direction, and there is a difference in luminance and color tone. Arise. When a structure called multi-domain in which one pixel of a liquid crystal display device is divided into a plurality of regions, the viewing angle characteristics of luminance and color tone are averaged and improved. Specifically, each pixel is composed of two or more (preferably 4 or 8) regions in which the initial alignment state of the liquid crystal molecules is different from each other, and the luminance and color tone bias depending on the viewing angle are averaged. Can be reduced. Further, the same effect can be obtained even if each pixel is composed of two or more different regions where the alignment direction of the liquid crystal molecules continuously changes in a voltage application state.

The present invention is also effective in an embodiment of a VA mode liquid crystal display device. The VA mode has a simple ON / OFF black-and-white response speed and a simple structure that does not require an alignment process by a rubbing process. As a preferred embodiment of the VA mode liquid crystal display device (hereinafter sometimes referred to as “first embodiment”), a first optical anisotropic layer satisfying the following formulas (III) and (IV), And a VA mode liquid crystal display device including a second optically anisotropic layer having at least one optical axis.
Formula (III) 0 nm <Rth (550) ≦ 300 nm
Formula (IV) Rth (550) / Re (550)> 10.
The second optically anisotropic layer may be an optical compensation film or the like generally referred to as an A plate. As a preferable example thereof, an optically anisotropic layer satisfying the following formulas (VIII) and (IX) It is.
Formula (VIII) 55 nm ≦ Re (550) ≦ 315 nm
Formula (IX) 0 nm ≦ Rth (550) ≦ 275 nm.

  In the VA mode liquid crystal display device of this aspect, the birefringence generated in the oblique direction during black display of the liquid crystal cell is compensated by the Rth of the first optical anisotropic layer. In order to realize compensation, the first optically anisotropic layer has a forward dispersion having a strong wavelength dispersion with respect to Rth (here, a tendency that Rth becomes smaller as the wavelength becomes longer is referred to as “forward dispersion”. "Strong forward dispersion" means that the gradient | ΔRth / Δλ | is large). However, in order to form an optically anisotropic layer exhibiting strong forward dispersion with Rth, the material is limited and / or it is difficult to control the wavelength dispersion of Rth to the desired level. It may be impossible to form an optically anisotropic layer having the above characteristics depending on the material. In the present invention, since the liquid crystal cell satisfies the above formula (1), the Rth wavelength dispersibility of the first optically anisotropic layer does not exhibit strong forward dispersibility to the extent conventionally required. Even so, it is compensated by the wavelength dispersion exhibited by the birefringence in the thickness direction of the liquid crystal cell, and ideal optical compensation is possible.

As another preferred embodiment of the VA mode liquid crystal display device (hereinafter sometimes referred to as “second embodiment”), one liquid anisotropic layer satisfying the following formulas (XV) and (XVI) is provided, respectively. And the upper and lower polarizing films, and when the slow axis of each optically anisotropic layer and the absorption axis of each adjacent polarizing film are projected on the same plane, they are parallel to each other. .
(XV) 30 nm ≦ Re (550) ≦ 80 nm
(XVI) 75 nm ≦ Rth (550) ≦ 155 nm.
Further, it is preferable that Rth (550) of the optically anisotropic layers disposed above and below the liquid crystal cell satisfy the relationship of the following formula (XVII) in relation to the liquid crystal layer.
(XVII) 0.7 ≦ (2 × Rth (550)) / Δn (550) × d ≦ 1.3
Here, Δn (550) is the refractive index anisotropy in the thickness direction of the liquid crystal layer at 550 nm, and d is the average thickness (nm) of the liquid crystal layer. In the present invention, since the thickness of the liquid crystal layer differs depending on the pixel region, the thickness in the formula (XVII) is an average thickness.

  In the VA mode liquid crystal display device according to the second aspect, the composites generated in the oblique direction during black display of the liquid crystal cell are formed by the Re and Rth of the two optically anisotropic layers arranged at symmetrical positions around the liquid crystal cell. In such a compensation mechanism, in order to realize ideal compensation, the wavelength dispersion of Rth of the two optically anisotropic layers arranged symmetrically has the birefringence of the liquid crystal layer. It is required to be adjusted so as to cancel the wavelength dispersion property. However, in order to make the Rth wavelength dispersibility desired, it is difficult to control the Rth wavelength dispersibility to a desired extent by limiting the materials used for forming the optically anisotropic layer. It may be. In the present invention, since the liquid crystal cell satisfies the above formula (1), the birefringent wavelength dispersibility of the liquid crystal layer is flattened. Accordingly, even when the wavelength dispersion of Rth of the two optically anisotropic layers does not show the wavelength dispersion required to the extent required in the past, for example, the wavelength dispersion is almost not shown and almost uniform in visible light. Even when an optically anisotropic layer exhibiting a good Rth is used, ideal optical compensation is possible.

Hereinafter, the operation and effect of the embodiment of the VA mode liquid crystal display device will be described with reference to the drawings. FIG. 2 schematically shows a configuration example of the first aspect in which the present invention is applied to a VA mode liquid crystal display device. The same members as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. In FIG. 2, the upper side is the observer side and the lower side is the backlight side.
The liquid crystal display device of FIG. 2 includes a liquid crystal cell LC ′ (1, 3, 5 ′), and a pair of an upper polarizing film P1 ′ and a lower polarizing film P2 ′ disposed so as to sandwich the liquid crystal cell LC ′. . The polarizing film is generally incorporated in a liquid crystal display device as a polarizing plate having protective films on both surfaces, but in FIG. 2, the outer protective film of the polarizing film is omitted for simplification of the drawing. .
In FIG. 2, the liquid crystal cell LC ′ is a VA mode liquid crystal cell, and when displaying black, the liquid crystal layer 5 ′ is homeotropically aligned as shown in FIG. Each of the upper substrate 1 and the lower substrate 3 has an alignment film (not shown) and an electrode layer (not shown) on the inner surface, and a color filter layer is formed on the inner surface of the substrate 1 on the viewer side. ing. Although the detailed structure is not shown in FIG. 2, the color filter formed on the inner surface of the substrate 1 includes three R, G, and B pixel regions, and the thickness of the liquid crystal layer 5 ′ corresponding to each pixel region is They are different from each other. For example, as shown in FIG. 3 (a), an RGB color filter is formed on the inner surface of the substrate 1, and the thickness of the R layer is smaller than the thickness of the B layer and the G layer. the thickness of the liquid crystal layer in the corresponding position, which satisfies the d _G <d _R and d _B <d _R. In a more preferable embodiment, as shown in FIG. 3B, the thicknesses of the B layer, the G layer, and the R layer are reduced in this order. In this embodiment, the thickness of the liquid crystal layer increases in this order, and satisfies the formula (2).

  In FIG. 2 again, between the upper substrate 1 and the upper polarizing film 8a, the first optical anisotropic layer 14 satisfying the above formulas (III) and (IV) is formed between the lower substrate 3 and the lower polarizing film. Between the film 8b, the second optical anisotropic layer 16 satisfying the above formulas (VIII) and (IX) is disposed. The second optically anisotropic layer 16 is preferably disposed with its in-plane slow axis 17 orthogonal to the absorption axis 9b of the lower polarizing film 8b. When the 2nd optically anisotropic layer 16 and the 1st optically anisotropic layer 14 consist of a polymer film or contain a polymer film layer, you may serve also as the protective film of polarizing film 8a and 8b, respectively. Of course, a protective film may be separately disposed between the second optically anisotropic layer 16 and the first optically anisotropic layer 14 and the polarizing films 8a and 8b. Is preferably used, for example, an isotropic film having a retardation of almost zero, such as a cellulose acylate film described in JP-A-2005-138375.

  Next, the optical compensation function of the liquid crystal display device of FIG. 2 will be described. 4 to 7 are views of the Poincare sphere as seen from the positive direction of the S2 axis. The Poincare sphere is a three-dimensional map that describes the polarization state. On the equator of the sphere, the polarization state of linearly polarized light with an ellipticity of 0 is represented. Point (i) in FIG. 4 indicates the polarization state in which light incident from the oblique direction on the liquid crystal display device in FIG. 2 from the oblique direction passes through the polarizing film 8b and becomes linearly polarized light. If the polarization state point (i) is converted into the polarization state point (ii) that is the extinction point on the S1 axis, the decrease in contrast when obliquely incident on the liquid crystal display device of FIG. The date is reduced. Therefore, the polarization state is converted from the point (i) to the point (ii) by passing through the second optically anisotropic layer 16, the liquid crystal layer 5 ′, and the first optically anisotropic layer 14. The birefringence of each may be adjusted. The change in the polarization state due to passing through the phase difference region is expressed by rotating a specific angle around a specific axis determined according to the optical characteristics of the phase difference region on the Poincare sphere. The The magnitude of the rotation angle is proportional to the phase difference of the phase difference region that has passed, and inversely proportional to the reciprocal of the wavelength of the incident light.

  After passing through the polarizing film 8b and passing through the second optical anisotropic layer 16 satisfying the above formulas (VIII) and (IX), as indicated by the arrows in FIG. The B light is converted into a polarization state in which the extinction point (ii) and the S1 coordinate substantially coincide with each other.

As described above, since the magnitude of the rotation angle on the Poincare sphere is proportional to the reciprocal of the wavelength of the incident light, there is a difference in the polarization state after conversion for R light, G light, and B light. In order to reduce this difference and make the polarization state in which the extinction point (ii) and the S1 coordinate coincide with each other, the second optical anisotropic layer 16 has both Re and Rth exhibiting reverse dispersion. Specifically, it is more preferable that the following formulas (X) to (XIII) are satisfied.
Formula (X) 0.6 ≦ Re (450) / Re (550) ≦ 1.0
Formula (XI) 1.0 ≦ Re (630) / Re (550) ≦ 1.25
Formula (XII) 0.6 ≦ Rth (450) / Rth (550) ≦ 1.0
Formula (XIII) 1.0 ≦ Rth (630) / Rth (550) ≦ 1.25

Next, when passing through the homeotropically aligned liquid crystal layer 5 ′ during black display, the polarization states of the R light, G light, and B light are indicated by the locus indicated by the arrow 5 ′ from the top to the bottom in FIG. And is expressed as rotation around the S1 axis.
By the way, in an aspect having a color filter composed of an R layer, a G layer, and a B layer, the three pixel regions are RGB regions, and the main wavelengths λ _R and λ _G that take the maximum transmittance of the R region, the G region, and the B region. And λ _B are λ _B , λ _G, and λ _R in ascending order. When the thicknesses of the liquid crystal layers in the R region, the G region, and the B region are d _R , d _G, and d _B , respectively, and the refractive index anisotropy Δn (λ) in the thickness direction at the wavelength λ of the liquid crystal layer, In a liquid crystal display device, Δn (λ _B )> Δn (λ _G )> Δn (λ _R ), so that there is no difference in the thickness of each color filter, for example, a color filter with a uniform thickness is used. When it is used, Δn (λ _B ) × d _B > Δn (λ _G ) × d _G > Δn (between the thickness direction retardations Δn (λ) of the respective pixel regions of the respective liquid crystal display devices. The relationship λ _R ) × d _R is established. The rotation angle (the length of the arrow) of the polarization state of the R light, the G light, and the B light by passing through the liquid crystal layer satisfying such a relational expression is proportional to the phase difference of the phase difference region that has passed, and Since each of them is proportional to the reciprocal of the wavelength, the polarization states of the R light, G light, and B light are largely separated by passing through the liquid crystal layer (see FIG. 6B).

On the other hand, in the aspect of the present invention, the thickness of the R layer, the G layer, and the B layer of the color filter is different as shown in FIG. d _B <d _G <d _R is satisfied. Therefore, when the conversion of the polarization state by passing through the liquid crystal layer 5 ′ is expressed as rotation on the Poincare sphere, the longer the wavelength, the larger the rotation angle is proportional to the reciprocal of the wavelength. On the other hand, since the equation (2) is satisfied, the longer the wavelength, the larger the wavelength in proportion to the phase difference at each wavelength, and as a result, the magnitude of the rotation angle depending on the wavelength. Difference (arrow length difference) is reduced as shown in FIG.

  Next, incident light passes through the first optically anisotropic layer 14, but the first optically anisotropic layer 14 satisfies the above formulas (III) and (IV). The change in the polarization state is represented by the movement of the S1-S2 plane in the normal direction indicated by the arrow 14 from the bottom to the top in FIG. Conventionally, as shown in FIG. 7B, the polarization state that has been separated depending on the wavelength by passing through the homeotropic liquid crystal layer is moved in the normal direction of the S1-S2 plane, as shown in FIG. However, it is difficult to move it on the S1 axis. For example, the optically anisotropic layer is designed so as to convert only G light onto the S1 axis, or the Rth of the first optically anisotropic layer is changed. In order to adjust to strong forward dispersibility, it was necessary to narrow the range of selection of materials used in production or to strictly control manufacturing conditions. In this embodiment, as shown in FIG. 6A, the separation of the R light, the G light, and the B light by passing through the liquid crystal layer 5 ′ is reduced. When the conversion of the polarization state by passing through 14 is expressed as a rotation on the Poincare sphere, the magnitude of the rotation angle is proportional to the reciprocal of the wavelength, and moves more in the order of B light, G light, and R light. It is possible to move on the S1 axis in any case.

In the first aspect, it is more preferable that the liquid crystal cell satisfies the formula (2), and the Rth of the first optical anisotropic layer exhibits a certain degree of forward dispersion. More preferably, the degree of forward dispersibility of Rth of the first optically anisotropic layer satisfies the following formulas (V) to (VII) while satisfying the formula (2) ″.
Formula (V) Rth (450) / Rth (550) ≧ 1
Formula (VI) Rth (630) / Rth (550) ≦ 1
Formula (VII) −30 nm ≦ Rth (630) −Rth (450) ≦ 0 nm.
A polymer film showing forward dispersibility to the extent that Rth satisfies the following formulas (V) to (VII) is easy to produce, and as a result, the range of selection of materials used as the first optically anisotropic layer is widened. Can be spread.

  4 to 7, the mode in which light passes in the order of the second optical anisotropic layer 16 → the liquid crystal cell 5 ′ → the first optical anisotropic layer 14 has been described. The same effect can be obtained even if the light passes in the order of the isotropic layer 14 → the liquid crystal cell 5 ′ → the second optically anisotropic layer 16.

FIG. 8 schematically shows a configuration example of the second aspect in which the present invention is applied to a VA mode liquid crystal display device. The same members as those in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted. In FIG. 8, the upper side is the observer side and the lower side is the backlight side.
The liquid crystal display device of FIG. 8 includes a liquid crystal cell LC ′ (1, 3, 5 ′), and a pair of an upper polarizing film P1 ″ and a lower polarizing film P2 ″ disposed so as to sandwich the liquid crystal cell LC ′. . The polarizing film is generally incorporated in a liquid crystal display device as a polarizing plate having protective films on both surfaces, but in FIG. 8, the outer protective film of the polarizing film is omitted for simplification of the drawing. .
In FIG. 8, the liquid crystal cell LC ′ is the same as the liquid crystal cell LC ′ in FIG.

  Optically anisotropic layers 20a and 20b are disposed between the upper substrate 1 and the upper polarizing film 8a and between the lower substrate 3 and the lower polarizing film 8b, respectively. The optically anisotropic layers 20a and 20b satisfy the above formulas (XV) and (XVI), respectively, and are the same optically anisotropic layer in which Re and Rth are equal to each other. The optically anisotropic layers 20a and 20b are arranged with their in-plane slow axes 21a and 21b parallel to the absorption axes 9a and 9b of the upper polarizing film 8a and the lower polarizing film 8b. That is, the optically anisotropic layers 20a and 20b are arranged with their slow axes orthogonal to each other. When the optically anisotropic layers 20a and 20b are made of a polymer film or include a polymer film layer, they may also serve as protective films for the polarizing films 8a and 8b, respectively. Of course, a protective film may be separately disposed between the optically anisotropic layers 20a and 20b and the polarizing films 8a and 8b, respectively. It is preferable to use an isotropic film having a retardation of almost 0, such as a cellulose acylate film described in JP-A-138375.

Also in this embodiment, as in the first embodiment, in the liquid crystal cell LC ′, the thickness of the R layer of the RGB color filter is thinner than the thickness of the B layer and the G layer, and the liquid crystal at the position corresponding thereto. By satisfying d _G <d _R and d _B <d _R with respect to the thickness of the layer, the effect of reducing the color shift occurring in the oblique direction is shown.

In the above description, the modes of the ECB mode and the VA mode have been described. However, the liquid crystal display device of the present invention is not limited to the liquid crystal display device in this mode. The liquid crystal cell performs display by changing the alignment state of the liquid crystal by an electric field, but can be classified as a display mode depending on a difference in alignment state in a state where no electric field is applied. Parallel alignment type ECB (Electrically Controlled Birefringence) mode in which liquid crystal molecules have an initial alignment parallel to the substrate, HAN (Hybrid Aligned Nematic) mode in which one side is vertical alignment and the other is parallel alignment, and liquid crystal molecules in the vicinity of the substrate However, in the intermediate layer between the substrates, the OCB (Optically Compensatory Bend) mode, or the bend mode, which is vertically aligned, is aligned parallel to the substrate, but the alignment direction is different between the upper and lower substrates, and the twisted structure The twisted angle of the TN (twisted nematic) mode and the normal TN mode range from 0 to 100 degrees, whereas the STN (super twisted nematic) mode twisted by 180 to 270 ° De, there is a cholesteric liquid crystal mode having a 270 ° twist structure of.
In addition, the IPS (In-Plane Switching) mode in which the liquid crystal alignment changes in the substrate plane by a so-called lateral electric field parallel to the substrate and parallel to the substrate surface, and in the same plane as the IPS mode in the electric field perpendicular to the substrate surface. A display mode such as an FLC (Ferroelectric Liquid Crystal) mode that switches display according to a change in orientation direction has been proposed. The liquid crystal display device of the present invention may be in any of the above modes.

Each display mode has its characteristics. For example, each of IPS and FLC modes has a wide viewing angle, OCB mode has a fast response speed in all gradation displays, and FLC and cholesteric liquid crystal modes provide memory. This is also possible and is effective in reducing power consumption. The TN mode has a high transmittance and a simple manufacturing process.
The liquid crystal display device of the present invention is preferably in the TN mode, VA mode, IPS mode, bend mode, and OCB mode in addition to the ECB mode.

  Furthermore, as described above, in any liquid crystal display device in any display mode, a structure called a multi-domain in which one pixel is divided into a plurality of regions is preferable because the vertical and horizontal viewing angle characteristics are averaged and the display quality is improved. .

  Depending on the driving method, the liquid crystal display device is an active matrix liquid crystal display device using a three-terminal or two-terminal anti-conductor element such as a TFT (Thin Film Transistor) or MIM (Metal Insulator Metal), and an STN type called time-division driving. And the present invention is effective in any of the embodiments.

Hereinafter, various members used in the liquid crystal display device of the present invention will be described in detail.
[Color filter]
It is preferable to arrange a color filter on one opposing surface of the pair of substrates of the liquid crystal cell of the liquid crystal display device of the present invention. Although it does not restrict | limit especially about a color filter, For example, it is preferable to arrange | position the color filter containing each layer of red (R), green (G), and blue (B) at least. An RGB color filter composed of R, G, and B and an RGBW color filter including a white (W) layer are preferable.
As described above, in the liquid crystal display device of the present invention, the liquid crystal cell includes three pixel regions, and the thickness of the liquid crystal layer in at least two of these pixel regions is different. One of the preferable means for achieving this configuration is that, among the thicknesses of the color filters arranged on the three pixel regions, the thicknesses of the color filters arranged in at least two pixel regions are different from each other. It is to be.
As a result, among the Rths of the color filters arranged on the three picture element regions, the Rths of the color filters arranged on at least two picture element regions can be made different. Can be achieved.

  The color filter can be produced, for example, by the following method. First, colored pixels, such as red, green, and blue, that match the purpose are formed on a transparent substrate. As a method of forming colored pixels such as red, green, and blue on a transparent substrate, the above-described staining method, printing method, or coloring resist method in which a colored photosensitive resin liquid is applied with a spin coater or the like and then patterned in a photolithography process. Furthermore, a laminating method or the like can be used as appropriate. For example, in a formation method including a coating process, a color filter having RGB layers having different thicknesses can be formed by adjusting the coating amount. In the case of using a laminate method, a color filter composed of RGB layers having different thicknesses can be formed by using transfer materials having different thicknesses.

When forming a black matrix using a black photosensitive resin, it is preferable to form it after forming the colored pixels. When a black matrix is first formed, the black photosensitive resin having a high optical density cures only the resin surface, so that the uncured resin is melted by the subsequent development process, particularly the repeated development process to form colored pixels. This is because the formed matrix may be peeled off in an extreme case.
In contrast, if the black matrix is formed last, the periphery of the black matrix is surrounded by colored pixels, and the developer is difficult to penetrate from the cross section, so that side etching is unlikely to occur and a black matrix with high optical density is formed. There is a great advantage that it can be formed.
Furthermore, when forming the colored layer for forming the colored pixels by the laminating method, if the black matrix is formed first, the place where the colored pixels are to be formed is closed in a substantially lattice pattern by the black matrix. Although there is a problem that air bubbles are sometimes easily involved, it is preferable to form a black matrix later because this problem does not occur.

  When the light transmittance of the colored pixel with respect to the photosensitive wavelength region of the black photosensitive resin exceeds 2%, it is preferable to add a light absorber or the like into the colored pixel in advance so that the transmittance is 2% or less. Various known compounds can be used as the light absorber used in this case. Examples include benzophenone derivatives (such as Michler's ketone), merocyanine compounds, metal oxides, benzotriazole compounds, and coumarin compounds. Among them, those that have good light absorption and retain 25% or more of light absorption performance even after heat treatment at 200 ° C. or higher are preferable. Specifically, titanium oxide, zinc oxide, benzotriazole compounds, coumarin compounds Compounds. Among these, coumarin compounds are particularly preferable from the viewpoints of both heat resistance and light absorption. The above-described heat treatment at 200 ° C. or higher is performed in order to further cure after forming each pixel.

  Next, a black photosensitive resin layer is provided on the entire surface of the transparent substrate so as to cover the pixel pattern. This is also a method of applying a black photosensitive resin liquid with a spin coater or a roll coater, or temporarily supporting the black photosensitive resin liquid in advance. An image forming material can be prepared by coating on the body, and the black photosensitive resin layer can be transferred onto the pixel pattern.

  Next, it exposes from the black photosensitive resin layer side through a photomask, and the black photosensitive resin layer of the light-shielding part (black matrix) in which a coloring pixel does not exist is hardened. The colored pixels are slightly misaligned due to the alignment error of the exposure tool and the thermal expansion of the substrate, the pixels themselves are thick and thin, and are not arranged at the designed dimensions. Is normal. This tendency is particularly strong for large-sized substrates. Therefore, when exposure is performed with a photomask according to the design pixel interval, a portion where the black matrix overlaps with the pixel or a portion where a gap is formed between the pixel is generated. Since the overlapped portion becomes a protrusion, and the portion where the gap is formed becomes light leakage, both are not preferable.

The color filter preferably satisfies the following conditions.
(I) 0 ≦ Re (630) ≦ 10 and | Rth (630) | ≦ 25
(II) | Re (400) −Re (700) | ≦ 10 and | Rth (400) −Rth (700) | ≦ 35
(In the above formulas (I) and (II), Re ₍ λ ₎ represents the in-plane retardation value (nm) at the wavelength λnm, and Rth ₍ λ ₎ represents the retardation value in the film thickness direction at the wavelength λnm (nm). )
Here, Re represents in-plane retardation, and this value is preferably as close to 0 as possible so as not to lower the front contrast ratio. Even when it is not 0, it is preferable that the slow axis of Re and the polarizing film absorption axis be parallel or orthogonal to each other.
Rth represents retardation in the thickness direction, does not affect the reduction in front contrast ratio, and contributes to improvement of the color tone viewing angle in the oblique direction. By giving Rth of the above condition to the color filter, it is possible to more completely perform optical compensation of the viewing angle for each pixel, and improve (reduce) the coloring phenomenon in the oblique direction of the liquid crystal display device in each display mode. )be able to.

The retardation of the color filter is adjusted, for example, by adding a retardation increasing agent or reducing agent to the photosensitive layer or the colored layer, which is a constituent layer of the transfer material, when the color filter is prepared using a transfer material. Also good.
Representative examples of the retardation increasing agent include compounds represented by the following formula and compounds similar thereto.

  An example of the retardation reducing agent is a compound represented by the following general formula (13).

In the general formula (13), R ¹¹ represents an alkyl group or an aryl group, and R ¹² and R ¹³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. Further, it is particularly preferable that the total number of carbon atoms of R ¹¹ , R ¹² and R ¹³ is 10 or more. R ¹¹ , R ¹² and R ¹³ may have a substituent, and the substituent is preferably a fluorine atom, an alkyl group, an aryl group, an alkoxy group, a sulfone group or a sulfonamide group, an alkyl group, an aryl group, Alkoxy groups, sulfone groups and sulfonamido groups are particularly preferred. Further, the alkyl group may be linear, branched or cyclic, and preferably has 1 to 25 carbon atoms, more preferably 6 to 25, and more preferably 6 to 20 (For example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, amyl, isoamyl, t-amyl, hexyl, cyclohexyl, heptyl, octyl, bicyclo Octyl, nonyl, adamantyl, decyl, t-octyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, didecyl) are particularly preferred . As the aryl group, those having 6 to 30 carbon atoms are preferable, and those having 6 to 24 carbon atoms (for example, phenyl group, biphenyl group, terphenyl group, naphthyl group, binaphthyl group, triphenylphenyl group) are particularly preferable.

[Liquid crystal cell Δnd]
Depending on the magnitude of the product Δnd of the cell gap of the liquid crystal cell and the refractive index anisotropy Δn of the liquid crystal layer, the brightness, contrast, and color tone of the liquid crystal display device change. Therefore, it is adjusted to the optimum Δnd for each display mode. In the ECB mode, Δn · d is set to 0.15 to 0.35 μm. The optimum value of Δn · d is 0.2 to 0.3 μm. In these ranges, since the white display luminance is high and the black display luminance is low, a bright and high-contrast display device can be obtained. Note that these optimum values are values in the transmission mode, and in the reflection mode, the optical path in the liquid crystal cell is doubled. Therefore, the optimum Δnd value is about ½ of the above. In other display modes, IPS and VA modes, good display characteristics can be obtained by setting Δn · d to 0.15 to 5 μm, TN mode to 0.2 to 0.5 μm, and OCB mode to 0.4 to 1.2 μm. It is done.

[Backlight]
The liquid crystal display device performs display by turning on and off the light passing through the liquid crystal cell, but when used as a transmission type, a cold cathode or a hot cathode fluorescent tube, or a light emitting diode, a field emission element, an electroluminescent element By arranging a backlight having a light source on the back surface, a bright and vivid display device is obtained.
There are two types of backlights: side-edge type backlights used for display devices used in portable terminals and notebook computers, and direct type backlights used for display devices such as televisions. The side edge type has a shape in which one or two fluorescent lamps are arranged at the end of the light guide plate, and has an advantage that the thickness of the backlight device can be reduced. On the other hand, in the direct backlight, the number of fluorescent lamps can be increased according to the required luminance, and high luminance can be easily obtained.
Furthermore, in order to increase the luminous efficiency of the backlight, a prismatic or lens-shaped condensing brightness enhancement sheet (film) is laminated, or a polarization reflection type brightness enhancement sheet (film) that improves light loss due to absorption of the polarizing plate. ) May be laminated between the backlight and the liquid crystal cell. In addition, a diffusion sheet (film) for making the light source of the backlight uniform may be laminated, and conversely, a sheet (film) formed by printing a reflection or diffusion pattern for giving an in-plane distribution to the light source. You may laminate.

[Field Sequential]
A full color display method using a liquid crystal display device includes a spatial mixing method and a time difference mixing method, and the latter is called a field sequential method.
The spatial mixing method is based on additive color mixing in which light in the red (R), green (G), and blue (B) wavelength regions is superimposed, and in the LCD, pixels that respectively shine in R, G, and B are arranged close to each other. At the same time, by changing the luminance of each pixel, these colors are arbitrarily mixed to obtain any color light. Further, color filters are generally used in the spatial mixing type LCD. However, since the color filter performs color display by absorbing light, the transmittance is low, and the field sequential backlight is superior in terms of power consumption.
The field sequential method is a color display method using a color mixture by “time division”. That is, when two or more colors of light are continuously switched to emit light, and the switching speed is set to exceed the temporal resolution of the human eye, the human can change the above two or more colors. This is a method that applies recognition by mixing colors.
In a field-sequential type full-color LCD, the backlight can emit light in one of the R, G, and B emission colors for each field in the moving image display, and the R is continuously R for each field. -G and B emission colors are switched (time-division) to emit light, and an arbitrary color light is obtained by sufficiently increasing the switching speed.

[application]
The liquid crystal display device of the present invention includes an image direct view type, an image projection type, and a light modulation type. The direct image viewing type includes OA equipment such as a notebook computer and a personal computer monitor, a multimedia display such as a television, and a small display device for a mobile phone and a mobile terminal. Furthermore, there are display devices for amusement machines and large display devices for vertical or floor use for meetings.
The image projection type includes a front projector type that projects directly onto the screen and a rear projector type that projects from the back of the screen. It is also effective for a portable projector using an LED light source or the like.
The light modulation type is effective for a display device called a three-dimensional display or a highly realistic display. For example, it is effective for a three-dimensional display using two liquid crystal cells and a cylindrical three-dimensional display composed of a plurality of rear projectors.

[Optical compensation sheet]
The liquid crystal display device of the present invention may have an optical compensation sheet. Optical compensation sheets are used in various liquid crystal display devices in order to eliminate image coloring and expand the viewing angle. As an optical compensation sheet, a stretched birefringent polymer film has been conventionally used. It has been proposed to use an optical compensation sheet having an optically anisotropic layer formed from a low-molecular or high-molecular liquid crystalline compound on a transparent support, instead of the optical compensation sheet comprising a stretched birefringent film. Since liquid crystalline compounds have various alignment forms, it has become possible to realize optical properties that cannot be obtained with conventional stretched birefringent polymer films by using liquid crystalline compounds. Furthermore, it functions as a protective film for the polarizing plate. It is also possible to serve as an optical compensation sheet in the plastic substrate.

The optical properties of the optical compensation sheet are determined according to the optical properties of the liquid crystal cell, specifically, the display mode differences as described above. When a liquid crystal compound is used, optical compensation sheets having various optical properties corresponding to various display modes of the liquid crystal cell can be produced. Various optical compensation sheets using liquid crystal compounds in the form of rods, spheroids, or disks corresponding to various display modes have already been proposed. For example, an optical compensation sheet for a TN mode liquid crystal cell optically compensates for an alignment state inclined to the substrate surface while eliminating the twisted structure of liquid crystal molecules by applying a voltage, and prevents contrast leakage by preventing light leakage in an oblique direction during black display. Improve viewing angle characteristics. The VA mode or IPS mode optical compensation sheet compensates for the viewing angle dependency of the polarizing plate, lowers the luminance of black display in all directions, and improves the viewing angle characteristic of contrast.
Furthermore, the optical property of the optical compensation sheet is designed to be an optimum value for each wavelength of light, thereby providing a liquid crystal display device having a wide visual field characteristic with little color change. It is particularly effective when combined with multi-gap and multi-domain.
In addition, the viewing angle can be narrowed so that the display can be observed only from a specific direction, instead of enlarging the viewing angle.

  An example of the optical compensation sheet is an optical compensation sheet having an optically anisotropic layer formed from a composition containing a liquid crystalline compound and a support that supports the optically anisotropic layer. Hereinafter, the optical compensation sheet of this aspect will be described in detail.

<< Optically anisotropic layer >>
The optically anisotropic layer is preferably designed so as to compensate for the liquid crystal compound in the liquid crystal cell in the black display of the liquid crystal display device. The alignment state of the liquid crystal compound in the liquid crystal cell in black display varies depending on the mode of the liquid crystal display device. The alignment state of the liquid crystal compound in this liquid crystal cell is described in IDW'00, FMC7-2, P411-414. The optically anisotropic layer is formed by disposing a composition containing a liquid crystalline compound on a surface, for example, a surface subjected to rubbing treatment along a predetermined rubbing axis or the like, and depending on the rubbing axis, molecules of the liquid crystalline compound Can be oriented and fixed in the oriented state.

  Examples of the liquid crystalline compound used for forming the optically anisotropic layer include both a rod-like liquid crystalline compound and a discotic liquid crystalline compound. The rod-like liquid crystal compound and the discotic liquid crystal compound may be a polymer liquid crystal or a low-molecular liquid crystal, and further include those in which the low-molecular liquid crystal is cross-linked and no longer exhibits liquid crystallinity. When a rod-like liquid crystalline compound is used for the preparation of the optically anisotropic layer, the rod-like liquid crystalline molecules are aligned so that the average direction of the axis projected on the support surface is parallel to the alignment axis. And fixed in that state. In addition, when a discotic liquid crystalline compound is used for the production of the optically anisotropic layer, the average direction of the axis obtained by projecting the short axis of the discotic liquid crystalline molecule onto the support surface is parallel to the alignment axis. It is preferable to form the film so that it is oriented and fixed in that state. The alignment state defined by the angle between the rod-like liquid crystal molecules and the disk-like liquid crystal molecules and the substrate surface may be any of horizontal (homogeneous) alignment, vertical alignment, and uniform tilt alignment. The hybrid orientation described below, in which the angle (inclination angle) formed by the above changes in the depth direction, is preferable.

《Bar-shaped liquid crystalline compound》
Examples of rod-like liquid crystalline compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines. , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used.
The rod-like liquid crystalline compound includes a metal complex. In addition, liquid crystal polymers containing rod-like liquid crystalline molecules in the repeating unit can also be used as the rod-like liquid crystalline compound. In other words, the rod-like liquid crystal molecule may be bonded to a (liquid crystal) polymer.
For rod-like liquid crystalline compounds, see Chapter 4, Chapter 7 and Chapter 11 of the Chemistry of the Quarterly Chemical Review Vol. 22 Liquid Crystal Chemistry (1994) edited by the Chemical Society of Japan, and the 142th Committee of the Japan Society for the Promotion of Science. Described in Chapter 3.
The birefringence of the rod-like liquid crystalline compound is preferably in the range of 0.001 to 0.7.

  The rod-like liquid crystalline compound preferably has a polymerizable group in order to fix its alignment state. The polymerizable group is preferably a radically polymerizable unsaturated group or a cationically polymerizable group. Specifically, for example, the polymerizable groups described in paragraphs [0064] to [0086] of JP-A-2002-62427 are described. Group and a polymerizable liquid crystal compound.

《Disk-like liquid crystalline compound》
Examples of discotic liquid crystal compounds include C.I. Destrade et al., Mol. Cryst. 71, 111 (1981), benzene derivatives described in C.I. Destrade et al., Mol. Cryst. 122, 141 (1985), Physics lett, A, 78, 82 (1990); Kohne et al., Angew. Chem. 96, 70 (1984) and the cyclohexane derivatives described in J. Am. M.M. Lehn et al. Chem. Commun. 1794 (1985), J. Am. Zhang et al., J. Am. Chem. Soc. 116, 2655 (1994), azacrown type and phenylacetylene type macrocycles are included.

  As a discotic liquid crystalline compound, a compound having liquid crystallinity in which a linear alkyl group, an alkoxy group, and a substituted benzoyloxy group are radially substituted as a side chain of the mother nucleus with respect to the mother nucleus at the center of the molecule Is also included. The molecule or the assembly of molecules is preferably a compound having rotational symmetry and imparting a certain orientation. The optically anisotropic layer formed by using a discotic liquid crystalline compound does not necessarily require that the discotic molecules contained in the optically anisotropic layer finally exhibit liquid crystallinity, for example, a low molecular weight discotic liquid crystal. The functional molecule has a group that reacts with heat or light, and as a result, it may be polymerized or cross-linked by reaction with heat or light to increase the molecular weight and lose liquid crystallinity. Preferred examples of the discotic liquid crystalline compound are described in JP-A-8-50206. The polymerization of discotic liquid crystalline molecules is described in JP-A-8-27284.

  In order to fix the discotic liquid crystalline molecules by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystalline molecules. A compound in which the discotic core and the polymerizable group are bonded via a linking group is preferable, whereby the orientation state can be maintained even in the polymerization reaction. Examples thereof include compounds described in paragraphs [0151] to “0168” in JP-A No. 2000-155216.

  In the hybrid alignment, the angle between the disk surface of the discotic liquid crystalline molecule and the surface of the support increases or decreases in the depth direction of the optically anisotropic layer and with an increase in the distance from the surface of the support. The angle preferably increases with increasing distance. Further, the change in angle can be a continuous increase, a continuous decrease, an intermittent increase, an intermittent decrease, a change including a continuous increase and a continuous decrease, or an intermittent change including an increase and a decrease. The intermittent change includes a region where the inclination angle does not change in the middle of the thickness direction. Even if the angle includes a region where the angle does not change, the angle only needs to increase or decrease as a whole. Furthermore, it is preferable that the angle changes continuously.

  The average direction of the major axis of the discotic liquid crystalline molecules on the support side can be generally adjusted by selecting the discotic liquid crystalline molecules or the material of the alignment film, or by selecting the rubbing treatment method. In addition, the disc surface direction of the surface side (air side) discotic liquid crystalline molecules can be generally adjusted by selecting the discotic liquid crystalline molecules or the type of additive used together with the discotic liquid crystalline molecules. Examples of the additive used together with the discotic liquid crystalline molecule include a plasticizer, a surfactant, a polymerizable monomer and a polymer. The degree of change in the orientation direction of the major axis can also be adjusted by selecting liquid crystalline molecules and additives as described above.

<< Other additives in optically anisotropic layer >>
Along with the liquid crystal compound, a plasticizer, a surfactant, a polymerizable monomer, and the like can be used in combination to improve the uniformity of the coating film, the strength of the film, the orientation of the liquid crystal molecules, and the like. It is preferable that the compound has compatibility with the liquid crystal molecules and can change the tilt angle of the liquid crystal molecules or does not inhibit the alignment.

  Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Preferably, it is a polyfunctional radically polymerizable monomer and is preferably copolymerizable with the above-described polymerizable group-containing liquid crystal compound. Examples thereof include those described in paragraph numbers [0018] to [0020] in JP-A No. 2002-296423. The amount of the compound added is generally in the range of 1 to 50% by mass and preferably in the range of 5 to 30% by mass with respect to the discotic liquid crystalline molecules.

  Examples of the surfactant include conventionally known compounds, and fluorine compounds are particularly preferable. Specific examples include compounds described in paragraph numbers [0028] to [0056] in JP-A-2001-330725.

The polymer used together with the discotic liquid crystalline molecule is preferably capable of changing the tilt angle of the discotic liquid crystalline molecule.
A cellulose ester can be mentioned as an example of a polymer. Preferable examples of the cellulose ester include those described in paragraph [0178] of JP-A No. 2000-155216. The addition amount of the polymer is preferably in the range of 0.1 to 10% by mass, and preferably in the range of 0.1 to 8% by mass with respect to the liquid crystal molecules so as not to disturb the alignment of the liquid crystal molecules. It is more preferable. The discotic nematic liquid crystal phase-solid phase transition temperature of the discotic liquid crystalline molecules is preferably 70 to 300 ° C, more preferably 70 to 170 ° C.

<< Formation of optically anisotropic layer >>
The optically anisotropic layer can be formed by disposing a liquid crystal compound and, if necessary, a composition containing a polymerizable initiator and any additive on the alignment film. The composition may be prepared as a coating solution.

  As a solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane, tetrachloroethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination.

  The coating liquid can be applied by a known method (eg, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

  The thickness of the optically anisotropic layer is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and most preferably 1 to 10 μm.

<Fixing the alignment state of liquid crystalline molecules>
It is preferable to fix the aligned liquid crystal molecules while maintaining the alignment state. The immobilization is preferably performed by a polymerization reaction. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. A photopolymerization reaction is preferred. Examples of photopolymerization initiators include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatics. Group acyloin compounds (described in US Pat. No. 2,722,512), polynuclear quinone compounds (described in US Pat. Nos. 3,046,127 and 2,951,758), combinations of triarylimidazole dimers and p-aminophenyl ketone (US patents) No. 3549367), acridine and phenazine compounds (JP-A-60-105667, US Pat. No. 4,239,850) and oxadiazole compounds (US Pat. No. 4,221,970).
The amount of the photopolymerization initiator used is preferably in the range of 0.01 to 20% by mass, more preferably in the range of 0.5 to 5% by mass, based on the solid content of the coating solution.

It is preferable to use ultraviolet rays for light irradiation for polymerization of liquid crystalline molecules. The irradiation energy is preferably in the range of ^{20mJ / cm 2 ~50J / cm 2} , more preferably in the range of 20~5000mJ / cm ^2, more preferably in the range of 100 to 800 mJ / cm ² . In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions.

  A protective layer may be provided on the optically anisotropic layer.

<Support>
The support of the optical compensation sheet is preferably transparent and is preferably made of at least one polymer film. You may comprise a transparent support body with a some polymer film. Specifically, the optical anisotropy of the support has a Re retardation value measured with light having a wavelength of 632.8 nm of 10 to 70 nm, and an Rth retardation value measured with light of wavelength 632.8 nm is 50. It is preferably ˜400 nm. In addition, when using two polymers of such an optically anisotropic layer for a liquid crystal display device, it is preferable that the Rth retardation value of one film is 50-200 nm. When one optically anisotropic polymer film is used for the liquid crystal display device, the Rth retardation value of the film is preferably 70 to 400 nm.

The average value of the slow axis angle of the polymer film is preferably 3 ° or less, more preferably 2 ° or less, and most preferably 1 ° or less. The direction of the average value of the slow axis angle is defined as the average direction of the slow axis. The standard deviation of the slow axis angle is preferably 1.5 ° or less, more preferably 0.8 ° or less, and most preferably 0.4 ° or less. The angle of the slow axis in the plane of the polymer film is defined as the angle formed by the slow axis and the reference line, where the stretching direction of the polymer film is the reference line (0 °). When the roll-shaped film is stretched in the width direction, the width direction is taken as a reference line, and when it is stretched in the longitudinal direction, the longitudinal direction is taken as a reference line.
The polymer film preferably has a light transmittance of 80% or more. The polymer film preferably has a photoelastic coefficient of 60 × 10 ⁻¹² m ² / N or less.

In a transmissive liquid crystal display device using an optical compensation sheet, “frame-shaped display unevenness” may occur in the periphery of the screen when the time after energization elapses. This unevenness is caused by an increase in the transmittance at the periphery of the screen, and is particularly noticeable during black display. In the transmissive liquid crystal display device, heat is generated from the backlight, and a temperature distribution is generated in the liquid crystal cell surface. The change in the optical characteristics (retardation value, slow axis angle) of the optical compensation sheet due to this temperature distribution is the cause of occurrence of “frame-like display unevenness”. The change in the optical characteristics of the optical compensation sheet is caused by elastic deformation of the optical compensation sheet because expansion or contraction of the optical compensation sheet due to temperature rise is suppressed by adhesion to the liquid crystal cell or the polarizing plate.
In order to suppress “frame-like display unevenness” that occurs in the transmissive liquid crystal display device, it is preferable to use a polymer film having high thermal conductivity for the transparent support of the optical compensation sheet. Examples of polymers having high thermal conductivity include cellulose polymers such as cellulose acetate (thermal conductivity (hereinafter the same): 0.22 W / (m · K)), polycarbonate (0.19 W / (m · K)). ) And a cyclic olefin polymer such as a norbornene polymer (0.20 W / (m · K)).
Commercially available polymers such as commercially available norbornene polymers (Arton, manufactured by JSR Corporation; Zeonoa, manufactured by Nippon Zeon Corporation, Zeonex; manufactured by Nippon Zeon Corporation) may be used. Polycarbonate copolymers are described in JP-A-10-176046 and JP-A-2001-253960.

The polymer film used as the support of the optical compensation sheet is preferably a cellulose polymer film, more preferably a cellulose ester film, and still more preferably a cellulose lower fatty acid ester film. Lower fatty acid means a fatty acid having 6 or less carbon atoms. The number of carbon atoms is preferably 2 (cellulose acetate), 3 (cellulose propionate) or 4 (cellulose butyrate). Mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate may be used.
Cellulose acetate (cellulose diacetate, cellulose triacetate) is particularly preferred. Most preferred is cellulose triacetate having an acetylation degree of 59.0 to 61.5%. The degree of acetylation means the amount of bound acetic acid per unit mass of cellulose. The degree of acetylation follows the measurement and calculation of the degree of acetylation in ASTM: D-817-91 (test method for cellulose acetate and the like).
The polymer has a viscosity average degree of polymerization (DP) of preferably 250 or more, and more preferably 290 or more. The polymer preferably has a narrow molecular weight distribution of Mm / Mn (Mm is a mass average molecular weight and Mn is a number average molecular weight) by gel permeation chromatography. The specific value of Mm / Mn is preferably 1.00 to 1.70, more preferably 1.30 to 1.65, and most preferably 1.40 to 1.60. .

In order to adjust the retardation of the polymer film, an aromatic compound having at least two aromatic rings can be used as a retardation increasing agent.
When a cellulose acylate film is used as the polymer film, the aromatic compound is used in the range of 0.01 to 20 parts by mass with respect to 100 parts by mass of the cellulose acylate. The aromatic compound is preferably used in a range of 0.05 to 15 parts by mass, and more preferably in a range of 0.1 to 10 parts by mass with respect to 100 parts by mass of cellulose acylate. Two or more aromatic compounds may be used in combination.
The aromatic ring of the aromatic compound includes an aromatic heterocyclic ring in addition to the aromatic hydrocarbon ring.
The molecular weight of the retardation increasing agent is preferably 300 to 800.
The retardation increasing agent is described in JP 2000-1111914, 2000-275434, 2001-166144 and International Publication No. 00/02619.

It is preferable to produce a polymer film by a solvent cast method. In the solvent cast method, a film is produced using a solution (dope) in which a polymer is dissolved in an organic solvent. The organic solvent is a solvent selected from ethers having 2 to 12 carbon atoms, ketones having 3 to 12 carbon atoms, esters having 2 to 12 carbon atoms, and halogenated hydrocarbons having 1 to 6 carbon atoms. It is preferable to contain.
The ether, ketone and ester may have a cyclic structure. A compound having two or more functional groups of ether, ketone and ester (that is, —O—, —CO— and —COO—) can also be used as the organic solvent. The organic solvent may have other functional groups such as alcoholic hydroxyl groups.

Examples of ethers include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole. Examples of the ketone include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclohexanone and methylcyclohexanone. Examples of esters include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate. Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol. The number of carbon atoms of the halogenated hydrocarbon is preferably 1 or 2, and most preferably 1. The halogen of the halogenated hydrocarbon is preferably chlorine. The proportion of halogenated hydrocarbon hydrogen atoms replaced with halogen is preferably 25 to 75 mol%, more preferably 30 to 70 mol%, and more preferably 35 to 65 mol%. More preferably, it is most preferable that it is 40-60 mol%. Methylene chloride is a representative halogenated hydrocarbon.
Two or more organic solvents may be mixed and used.

  A polymer solution (dope) can be prepared by a general method. A general method means processing at a temperature of 0 ° C. or higher (ordinary temperature or high temperature). The solution can be prepared by using a dope preparation method and apparatus in a normal solvent cast method. In the case of a general method, it is preferable to use a halogenated hydrocarbon (particularly methylene chloride) as the organic solvent. The amount of the polymer is adjusted so as to be contained in the obtained solution in an amount of 10 to 40% by mass. The amount of the polymer is more preferably 10 to 30% by mass. Arbitrary additives described later may be added to the organic solvent (main solvent). The solution can be prepared by stirring the polymer and the organic solvent at room temperature (0 to 40 ° C.). The high concentration solution may be stirred under pressure and heating conditions. Specifically, the polymer and the organic solvent are put in a pressure vessel and sealed, and stirred while heating to a temperature not lower than the boiling point of the solvent at normal temperature and in a range where the solvent does not boil. The heating temperature is usually 40 ° C. or higher, preferably 60 to 200 ° C., and more preferably 80 to 110 ° C.

Each component may be coarsely mixed in advance and then placed in a container. Moreover, you may put into a container sequentially. The container needs to be configured so that it can be stirred. The container can be pressurized by injecting an inert gas such as nitrogen gas. Moreover, you may utilize the raise of the vapor pressure of the solvent by heating. Or after sealing a container, you may add each component under pressure.
When heating, it is preferable to heat from the outside of the container. For example, a jacket type heating device can be used. The entire container can also be heated by providing a plate heater outside the container and piping to circulate the liquid.
It is preferable to provide a stirring blade inside the container and stir using this. The stirring blade preferably has a length that reaches the vicinity of the wall of the container. A scraping blade is preferably provided at the end of the stirring blade in order to renew the liquid film on the vessel wall.
Instruments such as a pressure gauge and a thermometer may be installed in the container. Each component is dissolved in a solvent in a container. The prepared dope is taken out of the container after cooling, or taken out and then cooled using a heat exchanger or the like.

The polymer solution (dope) may be prepared according to a cooling dissolution method. First, the polymer is gradually added to the organic solvent with stirring at a temperature around room temperature (-10 to 40 ° C.). When a plurality of solvents are used, the order of addition is not particularly limited. For example, after adding the polymer to the main solvent, another solvent (for example, a gelling solvent such as alcohol) may be added. It may be added and is effective in preventing non-uniform dissolution. The amount of the polymer is preferably adjusted so as to be contained in the mixture in an amount of 10 to 40% by mass.
The amount of the polymer is more preferably 10 to 30% by mass. Furthermore, you may add the arbitrary additive mentioned later in a mixture.

The mixture is then cooled to -100 to -10 ° C (preferably -80 to -10 ° C, more preferably -50 to -20 ° C, most preferably -50 to -30 ° C). The cooling can be performed, for example, in a dry ice / methanol bath (−75 ° C.) or a cooled diethylene glycol solution (−30 to −20 ° C.). Upon cooling in this manner, the mixture of polymer and organic solvent solidifies. Although the cooling rate is not particularly limited, in the case of batch-type cooling, the viscosity of the polymer solution increases with cooling, and the cooling efficiency is inferior. It is.
In the cooling dissolution method, after the polymer solution is swelled, it may be transferred in a short time through a cooling device having a predetermined cooling temperature. The faster the cooling rate, the better. However, 10,000 ° C./second is the theoretical upper limit, 1000 ° C./second is the technical upper limit, and 100 ° C./second is the practical upper limit. The cooling rate is a value obtained by dividing the difference between the temperature at the start of cooling and the final cooling temperature by the time from the start of cooling until the final cooling temperature is reached. Further, when this is heated to 0 to 200 ° C. (preferably 0 to 150 ° C., more preferably 0 to 120 ° C., most preferably 0 to 50 ° C.), a solution in which the polymer flows in the organic solvent is obtained. The temperature can be raised by simply leaving it at room temperature or in a warm bath.

A uniform solution is obtained as described above. If the dissolution is insufficient, the cooling and heating operations may be repeated. Whether or not the dissolution is sufficient can be determined by merely observing the appearance of the solution with the naked eye. In the cooling dissolution method, it is desirable to use a sealed container in order to avoid moisture mixing due to condensation during cooling. In the cooling and heating operation, when the pressure is applied during cooling and the pressure is reduced during heating, the dissolution time can be shortened. In order to perform pressurization and decompression, it is desirable to use a pressure-resistant container.
In addition, according to differential scanning calorimetry (DSC), a 20% by mass solution of cellulose acylate (acetylation degree: 60.9%, viscosity average polymerization degree: 299) dissolved in methyl acetate by the cooling dissolution method is There is a quasi-phase transition point between a sol state and a gel state in the vicinity of 33 ° C., and a uniform gel state is obtained below this temperature. Therefore, this solution needs to be stored at a temperature equal to or higher than the pseudo phase transition temperature, preferably about the gel phase transition temperature plus about 10 ° C. However, this pseudo phase transition temperature varies depending on the degree of acetylation of cellulose acylate, the degree of viscosity average polymerization, the solution concentration, and the organic solvent used.

A polymer film is produced from the prepared polymer solution (dope) by a solvent cast method. Moreover, it is preferable to add the above-mentioned retardation increasing agent to the dope.
The dope is cast on a drum or band and the solvent is evaporated to form a film. The dope before casting is preferably adjusted to have a solid content of 10 to 40%, more preferably 15 to 35%. The surface of the drum or band is preferably finished in a mirror state. Regarding casting and drying methods in the solvent casting method, U.S. Pat. Nos. 2,336,310, 2,367,603, 4,920,78, 2,429,297, 2,429,978, 2,607,704, 2,273,069, No. 2739070, British Patent Nos. 640731 and 736892, JP-B Nos. 45-4554, 49-5614, JP-A-60-176634, No. 60-203430, No. 62-11535 Are described in each publication. The dope is preferably cast on a drum or band having a surface temperature of 40 ° C. or lower. After casting, it is preferable to dry it by applying air for 2 seconds or more. The obtained film can be peeled off from the drum or band, and further dried by high-temperature air whose temperature is successively changed from 100 to 160 ° C. to evaporate the residual solvent. The above method is described in Japanese Patent Publication No. 5-17844. According to this method, it is possible to shorten the time from casting to stripping. In order to carry out this method, it is necessary for the dope to gel at the surface temperature of the drum or band during casting.

A plurality of polymer solutions may be cast.
When casting a plurality of polymer solutions, it is possible to produce a film while casting and laminating a solution containing a polymer from a plurality of casting openings provided at intervals in the direction of travel of the support (special features). (Kaisho 61-158414, JP-A-1-122419, and JP-A-11-198285). A film can also be produced by casting a polymer solution from two casting ports (Japanese Patent Publication Nos. 60-27562, 61-94724, 61-947245, 61-104413, 61-158413 and JP-A-6-134933). Furthermore, a polymer film casting method (described in JP-A-56-162617) in which a flow of a high-viscosity polymer solution is wrapped with a low-viscosity polymer solution and the high- and low-viscosity polymer solutions are simultaneously extruded can be employed.
Using two casting ports, the film formed on the support by the first casting port is peeled off, and the second casting is performed on the side that was in contact with the support surface to produce a film. A method (described in Japanese Patent Publication No. 44-20235) can also be carried out. The plurality of polymer solutions may be the same solution. In order to give a plurality of polymer layers different functions, a polymer solution corresponding to the functions may be extruded from each casting port.

The polymer solution can be cast simultaneously with a coating solution for other functional layers (eg, adhesive layer, dye layer, antistatic layer, antihalation layer, UV absorption layer, polarizing layer).
In the conventional monolayer liquid, it is necessary to extrude a polymer solution having a high concentration and a high viscosity in order to obtain a necessary film thickness. In that case, the stability of the polymer solution is poor and solid matter is generated, which often causes problems such as defects or poor flatness. As a solution to this, by casting a plurality of polymer solutions from the casting port, it is possible to extrude a highly viscous solution onto the support at the same time, and to improve the flatness and produce an excellent planar film. Furthermore, by using a concentrated polymer solution, it is possible to achieve a reduction in drying load and further increase the film production speed.

A plasticizer can be added to the polymer film in order to improve mechanical properties or increase the drying speed. As the plasticizer, phosphoric acid ester or carboxylic acid ester is used. Examples of phosphate esters include triphenyl phosphate (TPP) and tricresyl phosphate (TCP). Representative examples of the carboxylic acid ester include phthalic acid esters and citric acid esters. Examples of phthalic acid esters include dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), diphenyl phthalate (DPP) and diethylhexyl phthalate (DEHP). Examples of citrate esters include triethyl O-acetylcitrate (OACTE) and tributyl O-acetylcitrate (OACTB). Examples of other carboxylic acid esters include butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters. Phthalate plasticizers (DMP, DEP, DBP, DOP, DPP, DEHP) are preferably used. DEP and DPP are particularly preferred.
The addition amount of the plasticizer is preferably 0.1 to 25% by mass of the polymer amount, more preferably 1 to 20% by mass, and most preferably 3 to 15% by mass.

  A degradation inhibitor (eg, antioxidant, peroxide decomposer, radical inhibitor, metal deactivator, acid scavenger, amine) may be added to the polymer film. The deterioration preventing agents are described in JP-A-3-199201, JP-A-51907073, JP-A-5-194789, JP-A-5-271471, and JP-A-6-107854. The addition amount of the deterioration preventing agent is preferably 0.01 to 1% by mass of the solution (dope) to be prepared, and more preferably 0.01 to 0.2% by mass. When the addition amount is less than 0.01% by mass, the effect of the deterioration preventing agent is hardly recognized. When the addition amount exceeds 1% by mass, bleed-out (bleeding) of the deterioration preventing agent to the film surface may be observed. Particularly preferred deterioration inhibitors are butylated hydroxytoluene (BHT) and tribenzylamine (TBA).

The produced polymer film can further adjust the retardation by a stretching treatment. The draw ratio is preferably 3 to 100%. The thickness of the polymer film after stretching is preferably 20 to 200 μm, and more preferably 30 to 100 μm. By adjusting the conditions of the stretching treatment, the standard deviation of the slow axis angle of the optical compensation sheet can be reduced. The stretching process can be performed using a tenter. When the film produced by the solvent cast method is subjected to transverse stretching using a tenter, the standard deviation of the film slow axis angle can be reduced by controlling the state of the film after stretching. Specifically, a stretching process for adjusting the retardation value using a tenter is performed, and the polymer film immediately after stretching is stretched at a stretch ratio between the maximum stretch ratio and a stretch ratio of 1/2 of the maximum stretch ratio. By maintaining the temperature near the glass transition temperature, the standard deviation of the slow axis angle can be reduced. If the temperature of the film during this holding is lower than the glass transition temperature, the standard deviation will increase.
In addition, when performing longitudinal stretching between rolls, the standard deviation of the slow axis can be reduced by increasing the distance between the rolls.

When the polymer film functions as a transparent protective film of the polarizing film in addition to the function as a transparent support of the optical compensation sheet, it is preferable to subject the polymer film to a surface treatment.
As the surface treatment, corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment or ultraviolet irradiation treatment is performed. An acid treatment or an alkali treatment is preferably performed, and an alkali treatment is more preferably performed. When the polymer is cellulose acylate, the acid treatment or alkali treatment is carried out as a saponification treatment for cellulose acylate.

《Alignment film》
An alignment film may be used to form the optically anisotropic layer. The alignment film controls the alignment of the molecules of the liquid crystal compound in the optically anisotropic layer. The surface of the alignment film is preferably rubbed. When a coating liquid containing a liquid crystal compound is applied to the rubbing surface and dried, the liquid crystal molecules are aligned according to the rubbing axis of the rubbing surface.
However, if the alignment state is fixed and the optically anisotropic layer is formed after aligning the molecules of the liquid crystalline compound, the alignment film is not essential thereafter. That is, only the optically anisotropic layer on the alignment film in which the alignment state is fixed may be transferred onto a support or a polarizing film.

  The alignment film is an organic compound (eg, ω-tricosanoic acid) formed by rubbing treatment of an organic compound (preferably polymer), oblique deposition of an inorganic compound, formation of a layer having a microgroove, or Langmuir-Blodgett method (LB film). , Dioctadecylmethylammonium chloride, methyl stearylate). Furthermore, an alignment film in which an alignment function is generated by application of an electric field, application of a magnetic field, or light irradiation is also known.

  The alignment film is preferably formed by rubbing the surface of the polymer layer. In principle, the polymer used for the alignment film has a molecular structure having a function of aligning liquid crystal molecules. In the present invention, in addition to the function of aligning liquid crystalline molecules, a cross-linking having a function of aligning a side chain having a crosslinkable functional group (eg, double bond) to the main chain or aligning liquid crystalline molecules. It is preferable to introduce a functional functional group into the side chain. As the polymer used in the alignment film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used, and a plurality of combinations thereof can be used. Examples of the polymer include methacrylate copolymers, styrene copolymers, polyolefins, polyvinyl alcohol and modified polyvinyl alcohol, poly (N-methylol) described in paragraph No. [0022] of JP-A-8-338913. Acrylamide), polyester, polyimide, vinyl acetate copolymer, carboxymethylcellulose, polycarbonate and the like. Silane coupling agents can be used as the polymer. Water-soluble polymers (eg, poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol, modified polyvinyl alcohol) are preferred, gelatin, polyvinyl alcohol and modified polyvinyl alcohol are more preferred, and polyvinyl alcohol and modified polyvinyl alcohol are most preferred. . It is particularly preferable to use two types of polyvinyl alcohol or modified polyvinyl alcohol having different degrees of polymerization.

  The saponification degree of polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%. It is preferable that the polymerization degree of polyvinyl alcohol is 100-5000.

  A side chain having a function of aligning liquid crystal molecules generally has a hydrophobic group as a functional group. The specific type of functional group is determined according to the type of liquid crystal molecule and the required alignment state. For example, the modifying group of the modified polyvinyl alcohol can be introduced by copolymerization modification, chain transfer modification or block polymerization modification. Examples of modifying groups include hydrophilic groups (carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, amino groups, ammonium groups, amide groups, thiol groups, etc.), hydrocarbon groups having 10 to 100 carbon atoms, fluorine atoms Substituted hydrocarbon groups, thioether groups, polymerizable groups (unsaturated polymerizable groups, epoxy groups, azirinidyl groups, etc.), alkoxysilyl groups (trialkoxy, dialkoxy, monoalkoxy) and the like can be mentioned. As specific examples of these modified polyvinyl alcohol compounds, for example, paragraph numbers [0022] to [0145] in JP-A No. 2000-155216 and paragraph numbers [0018] to [0018] in JP-A No. 2002-62426 are described. [0022] and the like.

When a side chain having a crosslinkable functional group is bonded to the main chain of the alignment film polymer or a crosslinkable functional group is introduced into a side chain having a function of aligning liquid crystalline molecules, the alignment film polymer and the optically anisotropic film The polyfunctional monomer contained in the conductive layer can be copolymerized. As a result, not only between the polyfunctional monomer and the polyfunctional monomer, but also between the alignment film polymer and the alignment film polymer and between the polyfunctional monomer and the alignment film polymer is firmly bonded by a covalent bond. Therefore, the strength of the optical compensation sheet can be remarkably improved by introducing the crosslinkable functional group into the alignment film polymer.
The crosslinkable functional group of the alignment film polymer preferably contains a polymerizable group in the same manner as the polyfunctional monomer. Specifically, for example, those described in paragraphs [0080] to [0100] of JP-A No. 2000-155216 can be mentioned.

  Apart from the crosslinkable functional group, the alignment film polymer can also be crosslinked using a crosslinking agent. Examples of the crosslinking agent include aldehydes, N-methylol compounds, dioxane derivatives, compounds that act by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazole and dialdehyde starch. Two or more kinds of crosslinking agents may be used in combination. Specific examples include compounds described in paragraphs [0023] to [024] in JP-A-2002-62426. Aldehydes having high reaction activity, particularly glutaraldehyde are preferred.

  0.1-20 mass% is preferable with respect to a polymer, and, as for the addition amount of a crosslinking agent, 0.5-15 mass% is more preferable. The amount of the unreacted crosslinking agent remaining in the alignment film is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. By adjusting in this way, even if the alignment film is used for a long time in a liquid crystal display device or left in a high temperature and high humidity atmosphere for a long time, sufficient durability without reticulation can be obtained. May occur.

  The alignment film can be basically formed by applying the polymer on the transparent support containing the alignment film forming material and the crosslinking agent, followed by drying by heating (crosslinking) and rubbing treatment. As described above, the crosslinking reaction may be performed at any time after coating on the transparent support. When a water-soluble polymer such as polyvinyl alcohol is used as the alignment film forming material, the coating solution is preferably a mixed solvent of an organic solvent (eg, methanol) having a defoaming action and water. The ratio of water: methanol is preferably 0: 100 to 99: 1, and more preferably 0: 100 to 91: 9. Thereby, generation | occurrence | production of a bubble is suppressed and the defect of the layer surface of an orientation film and also an optically anisotropic layer reduces remarkably.

  As a coating method to be separated when forming the alignment film, a spin coating method, a dip coating method, a curtain coating method, an extrusion coating method, a rod coating method or a roll coating method is preferable. A rod coating method is particularly preferable. The film thickness after drying is preferably 0.1 to 10 μm. Heating and drying can be performed at 20 ° C to 110 ° C. In order to form sufficient cross-linking, 60 ° C to 100 ° C is preferable, and 80 ° C to 100 ° C is particularly preferable. The drying time can be 1 minute to 36 hours, preferably 1 minute to 30 minutes. The pH is preferably set to an optimum value for the crosslinking agent to be used. When glutaraldehyde is used, the pH is 4.5 to 5.5, and 5 is particularly preferable.

  The alignment film may be provided on the support or an undercoat layer formed on the support. The alignment film can be obtained by rubbing the surface after crosslinking the polymer layer as described above.

  For the rubbing treatment, a treatment method widely adopted as a liquid crystal alignment treatment process of LCD can be applied. That is, a method of obtaining the orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. In general, it is carried out by rubbing several times using a cloth in which fibers having a uniform length and thickness are flocked on average.

  Next, the alignment film is caused to function, and a composition (coating liquid) for forming an optically anisotropic layer is disposed on the alignment film, and the molecules of the liquid crystalline compound are aligned. Thereafter, if necessary, the alignment film polymer and the polyfunctional monomer contained in the optically anisotropic layer may be reacted, or the alignment film polymer may be crosslinked using a crosslinking agent. The thickness of the alignment film is preferably in the range of 0.1 to 10 μm.

[First and second optically anisotropic layers used in the first embodiment of the VA mode liquid crystal display]
As described above, when the present invention is applied to a VA mode liquid crystal display device, the first that satisfies the above formulas (III) and (IV), more preferably the above formulas (III) to (VII) is satisfied. It is preferable to use an optically anisotropic layer and a second optically anisotropic layer that satisfies the above formulas (VIII) and (IX), more preferably the above formulas (X) to (XIII). When these first and second optically anisotropic layers are polymer films, they can be bonded to a polarizer. Further, as a single member, for example, it can be incorporated into a liquid crystal display device as an optical compensation film. The polymer film material is preferably a polymer excellent in optical performance, transparency, mechanical strength, thermal stability, moisture shielding property, isotropy, etc., but any material that satisfies the above conditions May be used. Examples thereof include polycarbonate polymers, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, acrylic polymers such as polymethyl methacrylate, and styrene polymers such as polystyrene and acrylonitrile / styrene copolymer (AS resin). Polyolefins such as polyethylene and polypropylene, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers, polyethersulfone polymers , Polyether ether ketone polymers, polyphenylene sulfide polymers, vinylidene chloride polymers, vinyl alcohol polymers, vinyl butyral polymers, arylate polymers, polyoxymethylene polymers, epoxy polymers, or polymers mixed with the above polymers Take as an example.

  As a material for forming the polymer film, a thermoplastic norbornene resin can be preferably used. Examples of the thermoplastic norbornene-based resin include ZEONEX, ZEONOR manufactured by Nippon Zeon Co., Ltd., and ARTON manufactured by JSR Corporation.

  In addition, as a material for forming the polymer film, a cellulose polymer (hereinafter referred to as cellulose acylate) that has been conventionally used as a transparent protective film of a polarizing plate can be particularly preferably used. A representative example of cellulose acylate is triacetyl cellulose. Examples of cellulose as a cellulose acylate raw material include cotton linter and wood pulp (hardwood pulp, softwood pulp). Cellulose acylate obtained from any raw material cellulose can be used, and in some cases, it may be mixed and used. Detailed descriptions of these raw material celluloses can be found in, for example, Marusawa and Uda, “Plastic Materials Course (17) Fibrous Resin”, published by Nikkan Kogyo Shimbun (published in 1970), and the Japan Society of Invention and Innovation Technical Bulletin No. 2001. The cellulose described in No. -1745 (pages 7 to 8) can be used, and the cellulose acylate film is not particularly limited.

  The cellulose acylate film for the first and second optically anisotropic layers is preferably composed of a composition containing cellulose acylate having two or more types of substituents. Preferred examples of such cellulose acylates include mixed fatty acid esters having an acylation degree of 2 to 2.9 and an acyl group having 3 to 4 carbon atoms in the acetyl group. The acylation degree of the mixed fatty acid ester is more preferably 2.2 to 2.85, still more preferably 2.4 to 2.8. The degree of acetylation is preferably less than 2.5, more preferably less than 1.9. In the fatty acid ester residue, the aliphatic acyl group preferably has 2 to 20 carbon atoms. Specific examples include acetyl, propionyl, butyryl, isobutyryl, valeryl, pivaloyl, hexanoyl, octanoyl, lauroyl, stearoyl and the like, preferably acetyl, propionyl and butyryl.

The cellulose acylate may be a mixed acid ester having a fatty acid acyl group and a substituted or unsubstituted aromatic acyl group.
In the case of a cellulose fatty acid monoester, the substitution degree of the aromatic acyl group is preferably 2.0 or less, more preferably 0.1 to 2.0 with respect to the remaining hydroxyl group. In the case of cellulose fatty acid diester (cellulose diacetate), it is preferably 1.0 or less, more preferably 0.1 to 1.0, based on the remaining hydroxyl group.

  The cellulose acylate preferably has a mass average degree of polymerization of 350 to 800, and more preferably has a mass average degree of polymerization of 370 to 600. The cellulose acylate used in the present invention preferably has a number average molecular weight of 70000 to 230,000, more preferably 75000 to 230,000, and more preferably 78000 to 120,000. Further preferred.

  The cellulose acylate can be synthesized using an acid anhydride or acid chloride as an acylating agent. In the industrially most general synthesis method, cellulose obtained from cotton linter, wood pulp, etc. is converted into organic acids (acetic acid, propionic acid, butyric acid) corresponding to acetyl groups and other acyl groups, or their acid anhydrides (anhydrous anhydride). A cellulose ester is synthesized by esterification with a mixed organic acid component containing acetic acid, propionic anhydride, and butyric anhydride).

  The cellulose acylate film is preferably produced by a solvent cast method. About the manufacture example of the cellulose acylate film using a solvent cast method, U.S. Pat. Nos. 2,336,310, 2,367,603, 2,492,078, 2,492,977, 2,492,978, 2,607,704, 2,739,069 and 2,739,070, British Patent Nos. 640731 and 736892, Reference can also be made to the descriptions of JP-B-45-4554, JP-A-49-5614, JP-A-60-176834, JP-A-60-203430 and JP-A-62-115035. The cellulose acylate film may be subjected to a stretching treatment. Regarding the stretching method and conditions, for example, examples described in JP-A-62-115035, JP-A-4-152125, JP-A-4284221, JP-A-4-298310, JP-A-11-48271, etc. Can be helpful.

<Rth expression agent>
In order to produce a cellulose acylate film that satisfies the conditions for the first optically anisotropic layer, it is preferable to add an Rth enhancer to the cellulose acylate film. Here, the “Rth enhancer” is a compound having the property of developing birefringence in the thickness direction of the film.

  As the Rth enhancer, a compound having a large polarizability anisotropy having an absorption maximum in a wavelength range of 250 nm to 380 nm is preferable. As the Rth enhancer, a compound represented by the following general formula (I) can be particularly preferably used.

In the formula, X ¹ is a single bond, —NR ⁴ —, —O— or S—; X ² is a single bond, —NR ⁵ —, —O— or S—; X ³ is a single bond A bond, —NR ⁶ —, —O— or S—. R ¹ , R ² , and R ³ are each independently an alkyl group, an alkenyl group, an aromatic ring group, or a heterocyclic group; R ⁴ , R ^5, and R ⁶ are each independently a hydrogen atom , An alkyl group, an alkenyl group, an aryl group or a heterocyclic group.

  Preferred examples (I- (1) to IV- (10)) of the compounds represented by the general formula (I) are shown below, but the present invention is not limited to these specific examples.

  As the Rth enhancer, a compound represented by the following general formula (III) is also preferable. Hereinafter, the compound of the general formula (III) will be described in detail.

In the general formula (III), R ² , R ⁴ and R ⁵ each independently represent a hydrogen atom or a substituent, R ¹¹ and R ¹³ each independently represent a hydrogen atom or an alkyl group, and L ¹ and L ² are Each independently represents a single bond or a divalent linking group. Ar ¹ represents an arylene group or an aromatic heterocyclic ring, Ar ² represents an aryl group or an aromatic heterocyclic ring, n represents an integer of 3 or more, and n ² types of L ² and Ar ¹ are the same. It may or may not be. However, R ¹¹ and R ¹³ are different from each other, and the alkyl group represented by R ¹³ does not contain a hetero atom.

In general formula (III), R ² , R ⁴ and R ⁵ each independently represents a hydrogen atom or a substituent. Substituent T described later can be applied as the substituent.

R ² in the general formula (III) is preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group or a hydroxyl group, more preferably a hydrogen atom, an alkyl group or an alkoxy group, still more preferably a hydrogen atom or an alkyl group. Group (preferably 1 to 4 carbon atoms, more preferably a methyl group), an alkoxy group (preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, particularly Preferably it is C1-C4. Particularly preferred are a hydrogen atom, a methyl group and a methoxy group, and most preferred is a hydrogen atom.

R ⁴ in the general formula (III) is preferably a hydrogen atom or an electron donating group, more preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group, or a hydroxyl group, and still more preferably a hydrogen atom or a carbon number. An alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 12 carbon atoms (preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms And particularly preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and most preferably a hydrogen atom or a methoxy group.

R ⁵ in the general formula (III) is preferably a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an amino group or a hydroxyl group, more preferably a hydrogen atom, an alkyl group or an alkoxy group, still more preferably a hydrogen atom. An atom, an alkyl group (preferably having 1 to 4 carbon atoms, more preferably a methyl group), an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, and further preferably 1 to 6 carbon atoms). Particularly preferably, it has 1 to 4 carbon atoms. Particularly preferred are a hydrogen atom, a methyl group, and a methoxy group. Most preferably, it is a hydrogen atom.

R ¹¹ and R ¹³ in the general formula (III) each independently represent a hydrogen atom or an alkyl group, R ¹¹ and R ¹³ are different from each other, and the alkyl group represented by R ¹³ does not contain a hetero atom. Here, the hetero atom means an atom other than a hydrogen atom or a carbon atom, and examples thereof include an oxygen atom, a nitrogen atom, a sulfur atom, phosphorus, silicon, a halogen atom (F, Cl, Br, I), and boron.
The alkyl group represented by R ¹¹ and R ¹³ is linear, branched or cyclic and represents a substituted or unsubstituted alkyl group, preferably a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms. A substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted bicycloalkyl group having 5 to 30 carbon atoms (that is, a monovalent structure in which one hydrogen atom is removed from a bicycloalkane having 5 to 30 carbon atoms) And a tricyclo structure having more ring structures.

Preferable examples of the alkyl group represented by R ¹¹ and R ¹³ include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, n-pentyl group, iso-pentyl group, n -Hexyl group, n-heptyl group, n-octyl group, tert-octyl group, 2-ethylhexyl group, n-nonyl group, 1,1,3-trimethylhexyl group, n-decyl group, 2-hexyldecyl group, Examples thereof include a cyclohexyl group, a cycloheptyl group, a 2-hexenyl group, an oleyl group, a linoleyl group, and a linolenyl group. Examples of the cycloalkyl group include cyclohexyl, cyclopentyl, 4-n-dodecylcyclohexyl, and examples of the bicycloalkyl group include bicyclo [1,2,2] heptan-2-yl and bicyclo [2,2,2] octane-3. -Yl and the like.

R ¹¹ is more preferably a hydrogen atom, methyl group, ethyl group, n-propyl group, or isopropyl group, particularly preferably a hydrogen atom or methyl group, and most preferably a methyl group.
R ¹³ is particularly preferably an alkyl group containing 2 or more carbon atoms, more preferably an alkyl group containing 3 or more carbon atoms. Those having a branched or cyclic structure are particularly preferably used.

Hereinafter, specific examples (O-1 to O-20) of the alkyl group represented by R ¹³ will be described. However, the present invention is not limited to the following specific examples. In the specific examples below, “#” means the oxygen atom side.

Ar ¹ in the general formula (III) represents an arylene group or an aromatic heterocyclic ring, and all Ar ¹ in the repeating unit may be the same or different. Ar ² represents an aryl group or an aromatic heterocyclic ring.
In the general formula (III), the arylene group represented by Ar ¹ is preferably an arylene group having 6 to 30 carbon atoms, which may be a single ring or may form a condensed ring with another ring. Good. Further, if possible, it may have a substituent, and the substituent T described later can be applied as the substituent. More preferably, the arylene group represented by Ar ¹ has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include a phenylene group, a p-methylphenylene group, and a naphthylene group.
In general formula (III), the aryl group represented by Ar ² is preferably an aryl group having 6 to 30 carbon atoms, which may be monocyclic or may form a condensed ring with another ring. Good. Further, if possible, it may have a substituent, and the substituent T described later can be applied as the substituent. The aryl group represented by Ar ² has more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include a phenyl group, a p-methylphenyl group, and a naphthyl group.

In the general formula (III), the aromatic heterocycle represented by Ar ¹ or Ar ² may be an aromatic heterocycle containing at least one of an oxygen atom, a nitrogen atom or a sulfur atom, preferably 5 It is an aromatic heterocycle containing at least one of a 6-membered oxygen atom, nitrogen atom or sulfur atom. Moreover, you may have a substituent further if possible. Substituent T described later can be applied as the substituent.

In the general formula (III), specific examples of the aromatic heterocycle represented by Ar ¹ and Ar ² include, for example, furan, pyrrole, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, Indazole, purine, thiazoline, thiazole, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzthiazole , Benzotriazole, tetrazaindene, pyrrolotriazole, pyrazolotriazole and the like. Preferred as the aromatic heterocycle are benzimidazole, benzoxazole, benzthiazole, and benzotriazole.

In general formula (III), L ¹ and L ² each independently represents a single bond or a divalent linking group. L ¹ and L ² may be the same or different. Further, all L ² in the repeating unit may be the same or different.
Preferred as the divalent linking group are —O—, —NR— (R represents a hydrogen atom or an alkyl group or an aryl group which may have a substituent), —CO—, —SO ₂ —, -S-, an alkylene group, a substituted alkylene group, an alkenylene group, a substituted alkenylene group, an alkynylene group, and a group obtained by combining two or more of these divalent groups, more preferably -O-,- NR -, - CO -, - SO 2 NR -, - NRSO 2 -, - CONR -, - NRCO -, - COO-, and OCO-, an alkynylene group. R preferably represents a hydrogen atom.

In the compound represented by the general formula (III) in the present invention, Ar ¹ is bonded to L ¹ and L ^{2. When} Ar ¹ is a phenylene group, L ^1- Ar ¹ -L ² and L ^2- Ar ¹ -L ² is particularly preferably in a para-position (1,4-position) to each other.

  In general formula (III), n represents an integer greater than or equal to 3, Preferably it is 3-7, More preferably, it is 3-6, More preferably, it is 3-5.

  As the compound represented by the general formula (III), compounds represented by the following general formulas (IV) and (V) can be particularly preferably used.

In general formula (IV), R ² and R ⁵ each independently represent a hydrogen atom or a substituent, R ¹¹ and R ¹³ each independently represent a hydrogen atom or an alkyl group, and L ¹ and L ² Each independently represents a single bond or a divalent linking group. Ar ¹ represents an arylene group or an aromatic heterocyclic ring, Ar ² represents an aryl group or an aromatic heterocyclic ring, n represents an integer of 3 or more, and n ² types of L ² and Ar ¹ are the same. It may or may not be. However, R ¹¹ and R ¹³ are different from each other, and the alkyl group represented by R ¹³ does not contain a hetero atom.

In general formula (IV), R ² , R ⁵ , R ¹¹ , and R ¹³ have the same meanings as those in general formula (III), and preferred ranges are also the same. L ¹ , L ² , Ar ¹ and Ar ² are also synonymous with those in the general formula (III), and preferred ranges are also the same.

In general formula (V), R ² and R ⁵ each independently represent a hydrogen atom or a substituent, R ¹¹ , R ¹³ and R ¹⁴ each independently represent a hydrogen atom or an alkyl group, and L ¹ and L ² are Each independently represents a single bond or a divalent linking group. Ar ¹ represents an arylene group or an aromatic heterocyclic ring, Ar ² represents an aryl group or an aromatic heterocyclic ring, n represents an integer of 3 or more, and n ² types of L ² and Ar ¹ are the same. It may or may not be. However, R ¹¹ and R ¹³ are different from each other, and the alkyl group represented by R ¹³ does not contain a hetero atom.

In the general formula (V), R ² , R ⁵ , R ¹¹ and R ¹³ have the same meanings as those in the general formula (III), and preferred ranges are also the same. L ¹ , L ² , Ar ¹ and Ar ² have the same meanings as those in formula (III), and preferred ranges are also the same.
In the general formula (V), R ¹⁴ represents a hydrogen atom or an alkyl group, and as the alkyl group, alkyl groups shown as preferred examples of R ¹¹ and R ¹³ are preferably used. R ¹⁴ is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and further preferably a methyl group. R ¹¹ and R ¹⁴ may be the same or different, but both are particularly preferably methyl groups.

  Moreover, as a compound represented by the said general formula (V), the compound represented by general formula (VA) or general formula (VB) is also preferable.

In general formula (VA), R ² and R ⁵ each independently represent a hydrogen atom or a substituent, R ¹¹ and R ¹³ each independently represent a hydrogen atom or an alkyl group, L ¹ , L ² each independently represents a single bond or a divalent linking group. Ar ¹ represents an arylene group or an aromatic heterocyclic ring, n represents an integer of 3 or more, and n ² types of L ² and Ar ² may be the same or different. However, R ¹¹ and R ¹³ are different from each other, and the alkyl group represented by R ¹³ does not contain a hetero atom.

In general formula (VA), R ² , R ⁵ , R ¹¹ , R ¹³ , L ¹ , L ² , Ar ¹ , and n have the same meanings as those in general formula (III), and preferred ranges are also the same. is there.

In general formula (V-B), R ² and R ⁵ each independently represent a hydrogen atom or a substituent, and R ¹¹ , R ¹³ and R ¹⁴ each independently represent a hydrogen atom or an alkyl group, L ¹ and L ² each independently represents a single bond or a divalent linking group. Ar ¹ represents an arylene group or an aromatic heterocyclic ring, n represents an integer of 3 or more, and n types of L ¹ and Ar ² may be the same or different. However, R ¹¹ and R ¹³ are different from each other, and the alkyl group represented by R ¹³ does not contain a hetero atom.

In general formula (V-B), R ² , R ⁵ , R ¹¹ , R ¹³ , R ¹⁴ , L ¹ , L ² , Ar ¹ , n are as defined in general formulas (III) and (V). The preferred range is also the same.

The aforementioned substituent T will be described below.
The substituent T is preferably a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, Isopropyl group, t-butyl group, n-octyl group, 2-ethylhexyl group), cycloalkyl group (preferably a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, such as cyclohexyl group, cyclopentyl group, 4 -N-dodecylcyclohexyl group), a bicycloalkyl group (preferably a mono- or di-substituted bicycloalkyl group having 5 to 30 carbon atoms, that is, a monovalent group in which one hydrogen atom is removed from a bicycloalkane having 5 to 30 carbon atoms. For example, bicyclo [1,2,2] heptan-2-yl, bicyclo [2,2,2] octane-3 Yl), an alkenyl group (preferably a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, such as a vinyl group or an allyl group), a cycloalkenyl group (preferably a substituted or unsubstituted cyclohexane having 3 to 30 carbon atoms). An alkenyl group, that is, a monovalent group obtained by removing one hydrogen atom of a cycloalkene having 3 to 30 carbon atoms, such as 2-cyclopenten-1-yl and 2-cyclohexen-1-yl), a bicycloalkenyl group ( A substituted or unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms, that is, a monovalent group in which one hydrogen atom of a bicycloalkene having one double bond is removed. For example, bicyclo [2,2,1] hept-2-en-1-yl, bicyclo [2,2,2] oct-2-en-4-yl), al An aryl group (preferably a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, such as ethynyl group, propargyl group), an aryl group (preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms such as phenyl Group, p-tolyl group, naphthyl group), heterocyclic group (preferably a monovalent group obtained by removing one hydrogen atom from a 5- or 6-membered substituted or unsubstituted aromatic or non-aromatic heterocyclic compound And more preferably a 5- or 6-membered aromatic heterocyclic group having 3 to 30 carbon atoms (for example, 2-furyl group, 2-thienyl group, 2-pyrimidinyl group, 2-benzothiazolyl group),

A cyano group, a hydroxyl group, a nitro group, a carboxyl group, an alkoxy group (preferably a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, such as a methoxy group, an ethoxy group, an isopropoxy group, a t-butoxy group, n -Octyloxy group, 2-methoxyethoxy group), aryloxy group (preferably a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, for example, phenoxy group, 2-methylphenoxy group, 4-tert-butyl) Phenoxy group, 3-nitrophenoxy group, 2-tetradecanoylaminophenoxy group), silyloxy group (preferably a silyloxy group having 3 to 20 carbon atoms, for example, trimethylsilyloxy group, tert-butyldimethylsilyloxy group), hetero A ring oxy group (preferably a substituted or unsubstituted hete Ring oxy group, 1-phenyltetrazole-5-oxy group, 2-tetrahydropyranyloxy group), acyloxy group (preferably formyloxy group, substituted or unsubstituted alkylcarbonyloxy group having 2 to 30 carbon atoms, carbon number 6-30 substituted or unsubstituted arylcarbonyloxy groups such as formyloxy group, acetyloxy group, pivaloyloxy group, stearoyloxy group, benzoyloxy group, p-methoxyphenylcarbonyloxy group), carbamoyloxy group (preferably A substituted or unsubstituted carbamoyloxy group having 1 to 30 carbon atoms, such as N, N-dimethylcarbamoyloxy group, N, N-diethylcarbamoyloxy group, morpholinocarbonyloxy group, N, N-di-n-octyl Aminocarbonyloxy group, Nn-oct Rucarbamoyloxy group), alkoxycarbonyloxy group (preferably a substituted or unsubstituted alkoxycarbonyloxy group having 2 to 30 carbon atoms, such as methoxycarbonyloxy group, ethoxycarbonyloxy group, tert-butoxycarbonyloxy group, n-octylcarbonyl group) Oxy group), aryloxycarbonyloxy group (preferably a substituted or unsubstituted aryloxycarbonyloxy group having 7 to 30 carbon atoms, for example, phenoxycarbonyloxy group, p-methoxyphenoxycarbonyloxy group, pn-hexa Decyloxyphenoxycarbonyloxy group),

An amino group (preferably an amino group, a substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms, a substituted or unsubstituted anilino group having 6 to 30 carbon atoms, such as an amino group, a methylamino group, a dimethylamino group; , Anilino group, N-methyl-anilino group, diphenylamino group), acylamino group (preferably formylamino group, substituted or unsubstituted alkylcarbonylamino group having 1 to 30 carbon atoms, substituted or unsubstituted 6 to 30 carbon atoms, or Unsubstituted arylcarbonylamino group, for example, formylamino group, acetylamino group, pivaloylamino group, lauroylamino group, benzoylamino group), aminocarbonylamino group (preferably substituted or unsubstituted amino having 1 to 30 carbon atoms) Carbonylamino group, for example, carbamoylamino group, N, N-dimethylaminocarbonyl Mino group, N, N-diethylaminocarbonylamino group, morpholinocarbonylamino group), alkoxycarbonylamino group (preferably a substituted or unsubstituted alkoxycarbonylamino group having 2 to 30 carbon atoms, such as methoxycarbonylamino group, ethoxycarbonylamino Group, tert-butoxycarbonylamino group, n-octadecyloxycarbonylamino group, N-methyl-methoxycarbonylamino group), aryloxycarbonylamino group (preferably substituted or unsubstituted aryloxycarbonyl having 7 to 30 carbon atoms) An amino group such as a phenoxycarbonylamino group, a p-chlorophenoxycarbonylamino group, an mn-octyloxyphenoxycarbonylamino group, a sulfamoylamino group (preferably having 0 to 30 carbon atoms); Substituted or unsubstituted sulfamoylamino groups, such as sulfamoylamino groups, N, N-dimethylaminosulfonylamino groups, Nn-octylaminosulfonylamino groups, alkyl and arylsulfonylamino groups (preferably carbon A substituted or unsubstituted alkylsulfonylamino having 1 to 30 carbon atoms, a substituted or unsubstituted arylsulfonylamino group having 6 to 30 carbon atoms, such as a methylsulfonylamino group, a butylsulfonylamino group, a phenylsulfonylamino group, 2, 3 , 5-trichlorophenylsulfonylamino group, p-methylphenylsulfonylamino group), mercapto group, alkylthio group (preferably a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms such as methylthio group, ethylthio group, n- Hexadecylthio group), arylthio group (Preferably a substituted or unsubstituted arylthio group having 6 to 30 carbon atoms, for example, phenylthio group, p-chlorophenylthio group, m-methoxyphenylthio group), heterocyclic thio group (preferably substituted having 2 to 30 carbon atoms) Or an unsubstituted heterocyclic thio group, for example, 2-benzothiazolylthio group, 1-phenyltetrazol-5-ylthio group),

Sulfamoyl group (preferably a substituted or unsubstituted sulfamoyl group having 0 to 30 carbon atoms such as N-ethylsulfamoyl group, N- (3-dodecyloxypropyl) sulfamoyl group, N, N-dimethylsulfamoyl group , N-acetylsulfamoyl group, N-benzoylsulfamoyl group, N- (N′phenylcarbamoyl) sulfamoyl group), sulfo group, alkyl and arylsulfinyl group (preferably substituted or non-substituted having 1 to 30 carbon atoms) Substituted alkylsulfinyl groups, 6-30 substituted or unsubstituted arylsulfinyl groups such as methylsulfinyl group, ethylsulfinyl group, phenylsulfinyl group, p-methylphenylsulfinyl group), alkyl and arylsulfonyl groups (preferably C1-C30 substituted or unsubstituted An alkylsulfonyl group, a 6-30 substituted or unsubstituted arylsulfonyl group such as a methylsulfonyl group, an ethylsulfonyl group, a phenylsulfonyl group, a p-methylphenylsulfonyl group), an acyl group (preferably a formyl group, 2 carbon atoms) -30 substituted or unsubstituted alkylcarbonyl group, C7-30 substituted or unsubstituted arylcarbonyl group such as acetyl group and pivaloylbenzoyl group), aryloxycarbonyl group (preferably 7 carbon atoms) To 30 substituted or unsubstituted aryloxycarbonyl groups such as phenoxycarbonyl group, o-chlorophenoxycarbonyl group, m-nitrophenoxycarbonyl group, p-tert-butylphenoxycarbonyl group), alkoxycarbonyl group (preferably, C2-C30 substitution or Unsubstituted alkoxycarbonyl group, for example, methoxycarbonyl group, ethoxycarbonyl group, tert-butoxycarbonyl group, n-octadecyloxycarbonyl group), carbamoyl group (preferably a substituted or unsubstituted carbamoyl group having 1 to 30 carbon atoms, For example, carbamoyl group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-di-n-octylcarbamoyl group, N- (methylsulfonyl) carbamoyl group), aryl and heterocyclic azo groups (preferably C6-C30 substituted or unsubstituted arylazo group, C3-C30 substituted or unsubstituted heterocyclic azo group, for example, phenylazo group, p-chlorophenylazo group, 5-ethylthio-1,3,4 -Thiadiazol-2-ylazo group), imide group (preferably N-sul Succinimide group, N-phthalimido group), phosphino group (preferably a substituted or unsubstituted phosphino group having 2 to 30 carbon atoms, such as dimethylphosphino group, diphenylphosphino group, methylphenoxyphosphino group), phosphinyl group (Preferably a substituted or unsubstituted phosphinyl group having 2 to 30 carbon atoms, for example, phosphinyl group, dioctyloxyphosphinyl group, diethoxyphosphinyl group), phosphinyloxy group (preferably having 2 carbon atoms) -30 substituted or unsubstituted phosphinyloxy group, for example, diphenoxyphosphinyloxy group, dioctyloxyphosphinyloxy group, phosphinylamino group (preferably substituted or substituted with 2 to 30 carbon atoms) Unsubstituted phosphinylamino group such as dimethoxyphosphinylamino group, dimethylamino Phosphinyl amino group), a silyl group (preferably, represents a substituted or unsubstituted silyl group having 3 to 30 carbon atoms, e.g., trimethylsilyl group, tert- butyldimethylsilyl group, a phenyldimethylsilyl group).

  Among the above substituents, those having a hydrogen atom may be substituted with the above groups after removing this. Examples of such a functional group include an alkylcarbonylaminosulfonyl group, an arylcarbonylaminosulfonyl group, an alkylsulfonylaminocarbonyl group, and an arylsulfonylaminocarbonyl group. Specific examples include a methylsulfonylaminocarbonyl group, p- Examples include methylphenylsulfonylaminocarbonyl group, acetylaminosulfonyl group, and benzoylaminosulfonyl group.

  Moreover, when there are two or more substituents, they may be the same or different. If possible, they may be linked together to form a ring.

Preferred compounds represented by formula (VA) are those in which R ¹¹ is a methyl group, R ² and R ⁵ are both hydrogen atoms, and R ¹³ has 3 or more carbon atoms. An alkyl group, and L ¹ is a single bond, —O—, —CO—, —NR—, —SO ₂ NR—, —NRSO ₂ —, —CONR—, —NRCO—, —COO—, and OCO—. , An alkynylene group (R represents a hydrogen atom, an optionally substituted alkyl group or an aryl group, preferably a hydrogen atom), and L ² represents —O— or NR— (R represents a hydrogen atom). Represents an alkyl group or an aryl group which may have a substituent, preferably a hydrogen atom.), Ar ¹ is an arylene group, and n is 3-6.

  Specific examples of the compounds represented by formulas (VA) and (VB) will be described below in detail, but the present invention is not limited to the following specific examples.

The compound represented by the general formula (III) can be synthesized by first synthesizing a substituted benzoic acid, followed by a general ester reaction or amidation reaction between the substituted benzoic acid and a phenol derivative or aniline derivative. Any reaction may be used as long as it is a formation reaction. Examples include a method in which a substituted benzoic acid is converted to an acid halide and then condensed with a phenol derivative or aniline derivative, and a method in which a substituted benzoic acid is condensed with a phenol derivative or aniline derivative using a condensing agent or catalyst. It is done.
As a method for producing the compound represented by the general formula (III), a method in which a substituted benzoic acid is functionally converted to an acid halide and then condensed with a phenol derivative or an aniline derivative is preferable in consideration of the production process and the like.

  In the method for producing the compound represented by the general formula (III), examples of the reaction solvent include hydrocarbon solvents (preferably toluene and xylene), ether solvents (preferably dimethyl ether, tetrahydrofuran, dioxane and the like). ), Ketone solvents, ester solvents, acetonitrile, dimethylformamide, dimethylacetamide, and the like. These solvents may be used alone or in admixture of several kinds, and the solvent is preferably toluene, acetonitrile, dimethylformamide, or dimethylacetamide.

The reaction temperature is preferably 0 to 150 ° C, more preferably 0 to 100 ° C, still more preferably 0 to 90 ° C, and particularly preferably 20 ° C to 90 ° C.
Moreover, it is preferable not to use a base for this reaction. When a base is used, it may be either an organic base or an inorganic base, preferably an organic base, such as pyridine or tertiary alkylamine (preferably triethylamine, ethyldiisopropylamine, etc.).

  The compounds represented by the general formulas (VA) and (VB) can be synthesized by a known method. For example, in the case of a compound where n = 4, a raw material compound having the following structure A and a hydroxyl group The following intermediate B 2 molecule obtained by reaction with a derivative having a reactive site such as an amino group can be obtained by linking with 1 molecule of the following compound C. However, the synthesis method of the compounds represented by the general formulas (VA) and (VB) is not limited to this example.

In the formula, A represents a reactive group such as a hydroxyl group or a halogen atom, R ¹¹ , R ² , R ¹³ , and R ⁵ are as described above, and R ⁴ is a hydrogen atom or OR ¹⁴ described above. Is a substituent.

In the formula, A ′ represents a reactive group such as a carboxyl group, and R ¹¹ , R ² , R ¹³ , R ⁴ , R ⁵ , Ar ¹ , and L ¹ are as described above.

In the formula, B and B ′ represent a reactive group such as a hydroxyl group and an amino group, and Ar ² and L ² have the same meanings as Ar ¹ and L ¹ described above.

The content of the Rth enhancer represented by the general formulas (I) and (III) to (V) in the present invention relative to 100 parts by mass of cellulose acylate is preferably 0.1 to 30% by mass, and 1 to 25% by mass. Is more preferable, and 3 to 15% by mass is even more preferable.
When the cellulose acylate film is produced by a solvent cast method, the Rth enhancer may be added to the dope. The timing of adding the Rth enhancer is not particularly limited, and the Rth enhancer is dissolved in an organic solvent such as alcohol, methylene chloride, dioxolane, etc., and then added to the cellulose acylate solution (dope) or directly in the dope composition. It may be added inside.

  As the Rth enhancer, one type of the compounds represented by the general formulas (I) and (III) to (V) may be used alone, or two or more types may be mixed and used. Moreover, in this invention, combined use of the Rth expression agent represented by general formula (I), (III)-(V) is also preferable.

  The cellulose acylate film used as the first optically anisotropic layer may contain an ultraviolet absorber. The ultraviolet absorber can also function as an Rth enhancer. Examples of the ultraviolet absorbers include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like. System compounds are preferred. Further, ultraviolet absorbers described in JP-A-10-182621 and JP-A-8-337574 and polymer ultraviolet absorbers described in JP-A-6-148430 are also preferably used. In the cellulose acylate film used as the first optically anisotropic layer, the ultraviolet absorber is excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less, from the viewpoint of preventing deterioration of a polarizer and liquid crystal, and From the viewpoint of liquid crystal display properties, those that absorb less visible light having a wavelength of 400 nm or more are preferred.

  Specific examples of the benzotriazole ultraviolet absorber useful in the present invention include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert). -Butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butyl Phenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″, 6 ″ -tetrahydrophthalimidomethyl) -5′-methylphenyl) benzotriazole, 2,2 -Methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2 ' Hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2H-benzotriazol-2-yl) -6- (linear and side chain dodecyl) -4-methylphenol Octyl-3- [3-tert-butyl-4-hydroxy-5- (chloro-2H-benzotriazol-2-yl) phenyl] propionate and 2-ethylhexyl-3- [3-tert-butyl-4-hydroxy Examples include, but are not limited to, a mixture of -5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate. As commercially available products, TINUVIN 109, TINUVIN 171 and TINUVIN 326 (all manufactured by Ciba Specialty Chemicals Co., Ltd.) can be preferably used.

In order to produce a cellulose acylate film that satisfies the conditions for the first optically anisotropic layer, it is preferable to add an Rth enhancer to the cellulose acylate film. Here, the “Rth enhancer” is a compound having the property of developing birefringence in the thickness direction of the film. As the Rth enhancer, a compound having a large polarizability anisotropy having an absorption maximum in a wavelength range of 250 nm to 380 nm is preferable. The content of the Rth enhancer with respect to 100 parts by mass of cellulose acylate is preferably 0.1 to 30% by mass, more preferably 1 to 25% by mass, and still more preferably 3 to 15% by mass.
In addition, when manufacturing the said cellulose acylate film by the solvent cast method, you may add the said Rth expression agent in dope. The timing of adding the Rth enhancer is not particularly limited, and the Rth enhancer is dissolved in an organic solvent such as alcohol, methylene chloride, dioxolane, etc., and then added to the cellulose acylate solution (dope) or directly in the dope composition. It may be added inside.

<< Wavelength dispersion preparation agent >>
Moreover, in order to produce a cellulose acylate film that satisfies the conditions as the first optically anisotropic layer, an ultraviolet absorber may be added to the cellulose acylate film. The ultraviolet absorber can also function as a wavelength dispersion adjusting agent. Examples of the ultraviolet absorbers include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like. System compounds are preferred. Further, ultraviolet absorbers described in JP-A-10-182621 and JP-A-8-337574 and polymer ultraviolet absorbers described in JP-A-6-148430 are also preferably used. In the cellulose acylate film, as an ultraviolet absorber, from the viewpoint of preventing deterioration of a polarizer and a liquid crystal, it is excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less, and from the viewpoint of liquid crystal display property, a wavelength of 400 nm or more. Those that absorb less visible light are preferred.

《Plasticizer》
A plasticizer such as triphenyl phosphate or biphenyl phosphate may be added to the cellulose acylate film used as the first and second optically anisotropic layers.

The first optically anisotropic layer may be a layer formed from a liquid crystal composition, or may be a laminate of such a layer and a polymer film. The liquid crystal composition contains at least one liquid crystal compound. The liquid crystal compound is preferably selected from discotic liquid crystals having a disc-like molecular structure. Examples of preferable compounds of the discotic liquid crystal and examples of a method for forming an optically anisotropic layer using the liquid crystal composition are the same as described for the production of the optical compensation sheet.
In addition, when forming the said 1st optically anisotropic layer from a liquid-crystal composition, it is common to form on support bodies, such as a polymer film. Even if the birefringence of the polymer film as a support is positively utilized to satisfy the optical characteristics required for the first optically anisotropic layer as a laminate, the support also has a letter. Using a film having a foundation of almost 0 (for example, a cellulose acylate film described in JP-A-2005-138375), only a layer comprising the curable liquid crystal composition is required for the second optically anisotropic layer. It may be an aspect satisfying the optical characteristics.

<< Re expression agent >>
In order to produce a cellulose acylate film that satisfies the conditions for the second optically anisotropic layer, it is preferable to add a Re enhancer to the cellulose acylate film. Here, the “Re developing agent” is a compound having the property of developing birefringence within the film plane.

  The cellulose acylate film used as the second optically anisotropic layer may contain at least one liquid crystalline compound represented by the following general formula (A) as the Re developing agent.

In the formula, L ¹ and L ² each independently represent a single bond or a divalent linking group; A ¹ and A ² each independently represent —O— or —NR— (R represents a hydrogen atom or a substituent). ), -S- and -CO-; R ¹ , R ² and R ³ each independently represent a substituent; X represents a nonmetallic atom of Groups 14-16 ( However, a hydrogen atom or a substituent may be bonded to X); n represents any integer from 0 to 2.

  Among the compounds represented by the general formula (A), the Re expressing agent is preferably a compound represented by the following general formula (B).

In general formula (B), L ¹ and L ² each independently represents a single bond or a divalent linking group. A ¹ and A ² each independently represent a group selected from the group consisting of —O—, —NR— (R represents a hydrogen atom or a substituent), —S—, and CO—. R ¹ , R ² , R ³ , R ⁴ and R ⁵ each independently represents a substituent. n represents an integer of 0 to 2.

In the general formula (A) or (B), the divalent linking group represented by L ¹ and L ² preferably includes the following examples.

  More preferred are -O-, -COO-, and -OCO-.

In general formula (A) or (B), R ¹ is a substituent, and when there are a plurality of R ^{1 s} , they may be the same or different and may form a ring. The following can be applied as examples of the substituent.

  A halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a tert- Butyl group, n-octyl group, 2-ethylhexyl group), cycloalkyl group (preferably a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, such as cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl) Group), a bicycloalkyl group (preferably a substituted or unsubstituted bicycloalkyl group having 5 to 30 carbon atoms, that is, a monovalent group obtained by removing one hydrogen atom from a bicycloalkane having 5 to 30 carbon atoms. Bicyclo [1,2,2] heptan-2-yl group, bicyclo [2,2,2] octan-3-yl group), a A kenyl group (preferably a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, such as a vinyl group or an allyl group), a cycloalkenyl group (preferably a substituted or unsubstituted cycloalkenyl group having 3 to 30 carbon atoms, That is, it is a monovalent group in which one hydrogen atom of a cycloalkene having 3 to 30 carbon atoms is removed, for example, a 2-cyclopenten-1-yl, 2-cyclohexen-1-yl group), a bicycloalkenyl group (substituted or substituted). An unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms, that is, a monovalent group in which one hydrogen atom of a bicycloalkene having one double bond is removed. Bicyclo [2,2,1] hept-2-en-1-yl group, bicyclo [2,2,2] oct-2-en-4-yl group), alkynyl (Preferably a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, such as an ethynyl group or a propargyl group), an aryl group (preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms such as a phenyl group, p-tolyl group, naphthyl group), a heterocyclic group (preferably a monovalent group obtained by removing one hydrogen atom from a 5- or 6-membered substituted or unsubstituted aromatic or non-aromatic heterocyclic compound. And more preferably a 5- or 6-membered aromatic heterocyclic group having 3 to 30 carbon atoms, such as a 2-furyl group, a 2-thienyl group, a 2-pyrimidinyl group, and a 2-benzothiazolyl group), a cyano group. Hydroxyl group, nitro group, carboxyl group, alkoxy group (preferably a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, such as methoxy group, ethoxy group, isopropoxy group, Si group, tert-butoxy group, n-octyloxy group, 2-methoxyethoxy group), aryloxy group (preferably a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, such as phenoxy group, 2- Methylphenoxy group, 4-tert-butylphenoxy group, 3-nitrophenoxy group, 2-tetradecanoylaminophenoxy group), silyloxy group (preferably a silyloxy group having 3 to 20 carbon atoms, for example, trimethylsilyloxy group, tert -Butyldimethylsilyloxy group), heterocyclic oxy group (preferably a substituted or unsubstituted heterocyclic oxy group having 2 to 30 carbon atoms, 1-phenyltetrazol-5-oxy group, 2-tetrahydropyranyloxy group) An acyloxy group (preferably a formyloxy group, substituted or unsubstituted having 2 to 30 carbon atoms) Alkylcarbonyloxy group, substituted or unsubstituted arylcarbonyloxy group having 6 to 30 carbon atoms, such as formyloxy group, acetyloxy group, pivaloyloxy group, stearoyloxy group, benzoyloxy group, p-methoxyphenylcarbonyloxy group ), A carbamoyloxy group (preferably a substituted or unsubstituted carbamoyloxy group having 1 to 30 carbon atoms, for example, N, N-dimethylcarbamoyloxy group, N, N-diethylcarbamoyloxy group, morpholinocarbonyloxy group, N , N-di-n-octylaminocarbonyloxy group, Nn-octylcarbamoyloxy group), alkoxycarbonyloxy group (preferably a substituted or unsubstituted alkoxycarbonyloxy group having 2 to 30 carbon atoms, such as methoxycarbonyloxy Base An ethoxycarbonyloxy group, a tert-butoxycarbonyloxy group, an n-octylcarbonyloxy group), an aryloxycarbonyloxy group (preferably a substituted or unsubstituted aryloxycarbonyloxy group having 7 to 30 carbon atoms, for example, phenoxycarbonyl Oxy group, p-methoxyphenoxycarbonyloxy group, pn-hexadecyloxyphenoxycarbonyloxy group), amino group (preferably amino group, substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms, carbon number 6-30 substituted or unsubstituted anilino groups such as amino group, methylamino group, dimethylamino group, anilino group, N-methyl-anilino group, diphenylamino group), acylamino group (preferably formylamino group, C1-C30 substituted or unsubstituted a Alkylcarbonylamino group, substituted or unsubstituted arylcarbonylamino group having 6 to 30 carbon atoms, such as formylamino group, acetylamino group, pivaloylamino group, lauroylamino group, benzoylamino group), aminocarbonylamino group (preferably A substituted or unsubstituted aminocarbonylamino group having 1 to 30 carbon atoms, such as carbamoylamino group, N, N-dimethylaminocarbonylamino group, N, N-diethylaminocarbonylamino group, morpholinocarbonylamino group), alkoxycarbonyl An amino group (preferably a substituted or unsubstituted alkoxycarbonylamino group having 2 to 30 carbon atoms, such as a methoxycarbonylamino group, an ethoxycarbonylamino group, a tert-butoxycarbonylamino group, an n-octadecyloxycarboni group; Amino group, N-methyl-methoxycarbonylamino group), aryloxycarbonylamino group (preferably a substituted or unsubstituted aryloxycarbonylamino group having 7 to 30 carbon atoms such as phenoxycarbonylamino group, p-chlorophenoxy A carbonylamino group, an mn-octyloxyphenoxycarbonylamino group), a sulfamoylamino group (preferably a substituted or unsubstituted sulfamoylamino group having 0 to 30 carbon atoms, such as a sulfamoylamino group, N, N-dimethylaminosulfonylamino group, Nn-octylaminosulfonylamino group), alkyl and arylsulfonylamino groups (preferably substituted or unsubstituted alkylsulfonylamino groups having 1 to 30 carbon atoms, 6 to 6 carbon atoms) 30 substituted or unsubstituted aryl sulfoni An amino group, such as a methylsulfonylamino group, a butylsulfonylamino group, a phenylsulfonylamino group, a 2,3,5-trichlorophenylsulfonylamino group, a p-methylphenylsulfonylamino group, a mercapto group, an alkylthio group (preferably, C1-C30 substituted or unsubstituted alkylthio group, for example, methylthio group, ethylthio group, n-hexadecylthio group), arylthio group (preferably C6-C30 substituted or unsubstituted arylthio group, for example, phenylthio group , P-chlorophenylthio group, m-methoxyphenylthio group), heterocyclic thio group (preferably a substituted or unsubstituted heterocyclic thio group having 2 to 30 carbon atoms, such as 2-benzothiazolylthio group, 1- Phenyltetrazol-5-ylthio group), sulfamoyl group (preferably Preferably, the substituted or unsubstituted sulfamoyl group having 0 to 30 carbon atoms, such as N-ethylsulfamoyl group, N- (3-dodecyloxypropyl) sulfamoyl group, N, N-dimethylsulfamoyl group, N -Acetylsulfamoyl group, N-benzoylsulfamoyl group, N- (N'-phenylcarbamoyl) sulfamoyl group), sulfo group, alkyl and arylsulfinyl group (preferably substituted or unsubstituted having 1 to 30 carbon atoms) Alkylsulfinyl group, substituted or unsubstituted arylsulfinyl group having 6 to 30 carbon atoms, such as methylsulfinyl group, ethylsulfinyl group, phenylsulfinyl group, p-methylphenylsulfinyl group), alkyl and arylsulfonyl groups (preferably , Substituted or unsubstituted alkyls having 1 to 30 carbon atoms Honyl group, substituted or unsubstituted arylsulfonyl group having 6 to 30 carbon atoms, such as methylsulfonyl group, ethylsulfonyl group, phenylsulfonyl group, p-methylphenylsulfonyl group), acyl group (preferably formyl group, carbon number) A substituted or unsubstituted alkylcarbonyl group having 2 to 30 carbon atoms, a substituted or unsubstituted arylcarbonyl group having 7 to 30 carbon atoms such as an acetyl group and a pivaloylbenzoyl group, and an aryloxycarbonyl group (preferably having a carbon number) 7-30 substituted or unsubstituted aryloxycarbonyl groups such as phenoxycarbonyl group, o-chlorophenoxycarbonyl group, m-nitrophenoxycarbonyl group, p-tert-butylphenoxycarbonyl group), alkoxycarbonyl group (preferably , C2-C30 substitution or non-placement An alkoxycarbonyl group, for example, a methoxycarbonyl group, an ethoxycarbonyl group, a tert-butoxycarbonyl group, an n-octadecyloxycarbonyl group), a carbamoyl group (preferably a substituted or unsubstituted carbamoyl group having 1 to 30 carbon atoms, for example, Carbamoyl group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-di-n-octylcarbamoyl group, N- (methylsulfonyl) carbamoyl group), aryl and heterocyclic azo group (preferably carbon number) 6-30 substituted or unsubstituted arylazo groups, C3-C30 substituted or unsubstituted heterocyclic azo groups such as phenylazo group, p-chlorophenylazo group, 5-ethylthio-1,3,4-thiadiazole -2-ylazo group), imide group (preferably N-succin) Imide group, N-phthalimido group), phosphino group (preferably a substituted or unsubstituted phosphino group having 2 to 30 carbon atoms, such as dimethylphosphino group, diphenylphosphino group, methylphenoxyphosphino group), phosphinyl group (Preferably a substituted or unsubstituted phosphinyl group having 2 to 30 carbon atoms, for example, phosphinyl group, dioctyloxyphosphinyl group, diethoxyphosphinyl group), phosphinyloxy group (preferably having 2 carbon atoms) -30 substituted or unsubstituted phosphinyloxy group, for example, diphenoxyphosphinyloxy group, dioctyloxyphosphinyloxy group, phosphinylamino group (preferably substituted or substituted with 2 to 30 carbon atoms) Unsubstituted phosphinylamino group such as dimethoxyphosphinylamino group, dimethylaminophosphine Iniruamino group), a silyl group (preferably, represents a substituted or unsubstituted silyl group having 3 to 30 carbon atoms, e.g., trimethylsilyl group, tert- butyldimethylsilyl group, a phenyldimethylsilyl group).

  Among the above substituents, those having a hydrogen atom may be substituted with the above groups after removing this. Examples of such functional groups include an alkylcarbonylaminosulfonyl group, an arylcarbonylaminosulfonyl group, an alkylsulfonylaminocarbonyl group, and an arylsulfonylaminocarbonyl group. Examples thereof include a methylsulfonylaminocarbonyl group, a p-methylphenylsulfonylaminocarbonyl group, an acetylaminosulfonyl group, and a benzoylaminosulfonyl group.

R ¹ is preferably a halogen atom, alkyl group, alkenyl group, aryl group, heterocyclic group, hydroxyl group, carboxyl group, alkoxy group, aryloxy group, acyloxy group, cyano group, amino group, more preferably A halogen atom, an alkyl group, a cyano group, and an alkoxy group.

R ² and R ³ each independently represents a substituent. An example of R ¹ is given as an example. Preferred are a substituted or unsubstituted benzene ring and a substituted or unsubstituted cyclohexane ring. More preferred are a benzene ring having a substituent and a cyclohexane ring having a substituent, and further preferred are a benzene ring having a substituent at the 4-position and a cyclohexane ring having a substituent at the 4-position.

R ⁴ and R ⁵ each independently represents a substituent. An example of R ¹ is given as an example. Preferably, it is preferred that substituent constant sigma _p value of Hammett is greater than zero electron withdrawing group, sigma _p value has an electron withdrawing substituent of 0 to 1.5 Further preferred. Examples of such a substituent include a trifluoromethyl group, a cyano group, a carbonyl group, and a nitro group. R ⁴ and R ⁵ may combine to form a ring.
Regarding σ _p and σ _m of Hammett's substituent constants, for example, Naoki Inamoto's “Hammett's rule-structure and reactivity-” (Maruzen), edited by the Chemical Society of Japan “New Experimental Chemistry Course 14 Synthesis of Organic Compounds” Reaction V "2605 (Maruzen), Tadao Nakatani" Theoretical Organic Chemistry "217 (Tokyo Kagaku Dojin), Chemical Review, 91, 165-195 (1991) .

A ¹ and A ² each independently represent a group selected from the group consisting of —O—, —NR— (R is a hydrogen atom or a substituent), —S—, and CO—. Preferred is —O—, —NR— (R represents a substituent, and examples thereof include R ¹ ) and S—.

X represents a nonmetallic atom belonging to Groups 14-16. However, a hydrogen atom or a substituent may be bonded to X. X is preferably ═O, ═S, ═NR, ═C (R) R (wherein R represents a substituent, and examples of R ¹ are given as examples).
n represents an integer of 0 to 2, preferably 0 or 1.

  Specific examples of the compound represented by formula (A) or (B) are shown below, but examples of the Re enhancer are not limited to the following specific examples. Regarding the following compounds, unless otherwise specified, the number in parentheses () indicates the exemplified compound (X).

  The compound represented by the general formula (A) or (B) can be synthesized with reference to a known method. For example, exemplary compound (1) can be synthesized according to the following scheme.

In the above scheme, the synthesis from compound (1-A) to compound (1-D) is described in “Journal of Chemical Crystallography” (1997); 27 (9); p. 515-526. It can be performed with reference to the method described in 1.
Further, as shown in the above scheme, methanesulfonic acid chloride was added to a tetrahydrofuran solution of the compound (1-E), N, N-diisopropylethylamine was added dropwise and stirred, and then N, N-diisopropylethylamine was added, Exemplary solution (1) can be obtained by adding dropwise a tetrahydrofuran solution of compound (1-D) and then adding a tetrahydrofuran solution of N, N-dimethylaminopyridine (DMAP).

Moreover, you may use the rod-shaped aromatic compound of pages 11-14 of Unexamined-Japanese-Patent No. 2004-50516 as said Re expression agent.
Further, as the Re enhancer, one kind of compound can be used alone, or two or more kinds of compounds can be mixed and used. It is preferable to use two or more compounds different from each other as the Re enhancer because the retardation adjustment range is widened and can be easily adjusted to a desired range.
The addition amount of the Re enhancer is preferably 0.1 to 20% by mass, and more preferably 0.5 to 10% by mass with respect to 100 parts by mass of cellulose acylate. When the cellulose acylate film is produced by a solvent cast method, the Re enhancer may be added to the dope. The addition may be performed at any timing. For example, the Re developing agent may be dissolved in an organic solvent such as alcohol, methylene chloride, dioxolane, etc., and then added to the cellulose acylate solution (dope) or directly. You may add during dope composition.

Moreover, as a preferable combination of the Re developing agent used for the production of the second optically anisotropic layer, a liquid crystal compound represented by the general formula (A) and a liquid crystal represented by the following general formula (a) And a combination with an ionic compound. When these liquid crystalline compounds are used, Re can be an optically anisotropic layer having a reverse wavelength dispersion with a steep gradient (property that Re increases as the wavelength increases).
Formula (a): Ar ¹ -L ¹² -XL ¹³ -Ar ²
In the general formula (a), Ar ¹ and Ar ² are each independently an aromatic group; L ¹² and L ¹³ are each independently an —O—CO— or —CO—O— group; X Is a 1,4-cyclohexylene group, a vinylene group or an ethynylene group.
The aromatic group represented by Ar ¹ and Ar ² includes both an aromatic hydrocarbon ring group and an aromatic heterocyclic group. Specific examples include a phenyl group and a naphthyl group. The aromatic heterocyclic group has at least one hetero atom selected from a nitrogen atom, an oxygen atom and a sulfur atom in the ring. A 5- to 7-membered ring is preferable, and a 5- or 6-membered ring is preferable.
The aromatic group represented by each of Ar ¹ and Ar ² may have a substituent if possible. Specific examples of the substituent are the same as the examples of the substituent represented by R ¹ in the general formula (A).

  Specific examples of the liquid crystalline compound represented by the general formula (a) include rod-like aromatic compounds described in [0040] to [0044] on pages 11 to 14 of JP-A-2004-50516.

The liquid crystalline compound used as a Re developing agent is added to a polymer composition (preferably a cellulose acylate composition) together with other additives that are optionally added. The addition amount of the liquid crystal compound is preferably 0.1 to 30% by mass, and more preferably 0.1 to 20% by mass. When the liquid crystalline compound is added in this range, desired optical characteristics can be achieved, and it is preferable from the viewpoint of suppressing the crying out (bleed out) of the compound from the film that is concerned that the excessive amount is excessive. Further, the mass ratio of the liquid crystalline compound to all additives is preferably 40 to 100% by mass, and more preferably 50 to 100% by mass. It is preferable from the viewpoint of achieving desired optical characteristics that the ratio of the liquid crystalline compound as the Re developing agent to the total additive is within the above range.
Moreover, in the aspect which uses together the liquid crystalline compound represented by the said general formula (A), and the liquid crystalline compound represented by the said general formula (a), the optical film of this invention which satisfy | fills the said characteristic stably. It is preferable to adjust the combination ratio so that can be prepared.

[Optically anisotropic layers A and B used in the second embodiment of the VA mode liquid crystal display device]
As described above, when the present invention is applied to a VA mode liquid crystal display device, the above formulas (XV) and (XVI) are satisfied, more preferably the above formulas (XV) and (XVI) are satisfied and equal to Re It is preferable to use optically anisotropic layers A and B having Rth and Rth. When these optically anisotropic layers A and B are polymer films, they can be bonded to a polarizer. Further, as a single member, for example, it can be incorporated into a liquid crystal display device as an optical compensation film. The polymer film material is preferably a polymer excellent in optical performance, transparency, mechanical strength, thermal stability, moisture shielding property, isotropy, etc., but any material that satisfies the above conditions May be used. A specific example is the same as the polymer material that can be used for the production of the first and second optically anisotropic layers used in the first embodiment of the VA mode liquid crystal display device.

For example, the optically anisotropic layers A and B are optically different in that Rth is low in wavelength dispersion (less variation in Rth depending on the wavelength) in the visible light range while satisfying the above formulas (XV) and (XVI). When the isotropic layer is used, it is preferable to use a norbornene-based polymer film. Specific examples of the norbornene-based polymer film that can be used are the same as the specific examples of the norbornene-based polymer film that can be used for the production of the first and second optically anisotropic layers of the first aspect.
The optically anisotropic layers A and B may be made of a cellulose acylate film. In particular, the optically anisotropic layers A and B are optically satisfying the above formulas (XV) and (XVI), and having Rth having inverse wavelength dispersion in the visible light range (property that Rth increases as the wavelength increases). In the case of an anisotropic layer, the acyl substituent of cellulose acylate contained as a main component (a component of 50% by mass or more in solid content) in the cellulose acylate film is at least selected from acetyl, propionyl and butyryl. One type of cellulose acylate film is preferably used.

Further, in order to adjust the absolute value of retardation and / or wavelength dispersion of retardation of the optically anisotropic layers A and B, any one of the above-described Re developing agents, reducing agents, Rth developing agents, and reducing agents may be used. It may be added to the polymer film. Regarding the Re developing agent and reducing agent and the Rth developing agent and reducing agent that can be used in the production of the optically anisotropic layers A and B, materials that can be used in the production of the first and second optically anisotropic layers described above. It is the same.
For example, it is preferable to use at least one Rth enhancer for the production of the optically anisotropic layers A and B. In particular, the optically anisotropic layers A and B are optically satisfying the above formulas (XV) and (XVI), and Rth is forward wavelength dispersive in the visible light region (property that Rth becomes larger as the wavelength is shorter). In the case of an anisotropic layer, the Rth enhancer is preferably a compound having an absorption maximum at 250 nm to 380 nm, and among them, a compound represented by the following general formula (I):

Is preferably used. The definition of each group in the formula is as described in the first aspect.
A polymer composition containing at least one compound represented by the formula (I) as an Rth enhancer and a polymer (preferably cellulose acylate) is prepared, and a polymer film is obtained by a solution casting method. It is preferable to use it as the optically anisotropic layers A and B. The compound of the general formula (I) is preferably added in an amount of 0.1 to 30% by mass with respect to the total mass (solid content) of the polymer composition.

  Further, the optically anisotropic layers A and B satisfy the above formulas (XV) and (XVI), exhibit a relatively high Re, and have a reverse wavelength dispersibility (long) with a steep Rega gradient in the visible light region. In the case of an optically anisotropic layer having a property that Re increases as the wavelength increases, it is represented by the general formula (A) in the first embodiment as in the case of the production of the second optically anisotropic layer. Along with the liquid crystal compound, the liquid crystal compound represented by the general formula (a) may be used as a Re developing agent. Details and preferred examples of these compounds are as described above.

  The thickness of each optically anisotropic layer used in the first and second aspects of the VA mode liquid crystal display device is not particularly limited, but is thin while satisfying the optical characteristics required for each optically anisotropic layer. In order to meet the demands for making the optical anisotropic layer, the thickness of each optically anisotropic layer is preferably 30 to 200 μm.

[Elliptically polarizing plate]
In the liquid crystal display device of the present invention, an elliptically polarizing plate in which an optically anisotropic layer is integrated with a linearly polarizing film (polarizing film) can be used. The elliptically polarizing plate is manufactured by laminating the optical compensation sheet and a linearly polarizing film (hereinafter simply referred to as “polarizing film” or “polarizing film” as “linearly polarizing film”). Can do. The optical compensation sheet may also serve as a protective film for the linearly polarizing film.

  The linear polarizing film is manufactured by Optiva Inc. And a polarizing film comprising a binder and iodine or a dichroic dye is preferable. The iodine and the dichroic dye in the linearly polarizing film exhibit deflection performance by being oriented in the binder. It is preferable that the iodine and the dichroic dye are aligned along the binder molecule, or the dichroic dye is aligned in one direction by self-assembly such as liquid crystal. Currently, commercially available polarizers are made by immersing a stretched polymer in a solution of iodine or dichroic dye in a bath and allowing iodine or dichroic dye to penetrate into the binder. Is common.

  Commercially available polarizing films have iodine or dichroic dye distributed about 4 μm (about 8 μm on both sides) from the polymer surface, and a thickness of at least 10 μm is necessary to obtain sufficient polarization performance. The penetrability can be controlled by the solution concentration of iodine or dichroic dye, the temperature of the bath, and the immersion time. As described above, the lower limit of the binder thickness is preferably 10 μm. The upper limit of the thickness is preferably as thin as possible from the viewpoint of light leakage of the liquid crystal display device. It is preferably not more than a commercially available polarizing plate (about 30 μm), preferably 25 μm or less, and more preferably 20 μm or less. When the thickness is 20 μm or less, the light leakage phenomenon is not observed on a 17-inch liquid crystal display device.

  The binder of the polarizing film may be cross-linked. As the crosslinked binder, a polymer that can be crosslinked per se can be used. A polarizing film can be formed by reacting a polymer having a functional group or a binder obtained by introducing a functional group into a polymer between the binders by light, heat, or pH change. Moreover, you may introduce | transduce a crosslinked structure into a polymer with a crosslinking agent. Crosslinking is generally carried out by applying a coating liquid containing a polymer or a mixture of a polymer and a crosslinking agent on a transparent support and then heating. Since it is only necessary to ensure durability at the stage of the final product, the crosslinking treatment may be performed at any stage until the final polarizing plate is obtained.

  As the binder for the polarizing film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used. Examples of the polymer include the same polymers as those described in the alignment film. Most preferred are polyvinyl alcohol and modified polyvinyl alcohol. The modified polyvinyl alcohol is described in JP-A-8-338913, JP-A-9-152509, and JP-A-9-316127. Two or more kinds of polyvinyl alcohol and modified polyvinyl alcohol may be used in combination.

  The addition amount of the crosslinking agent in the binder is preferably 0.1 to 20% by mass with respect to the binder. The orientation of the polarizing element and the wet heat resistance of the polarizing film are improved.

The alignment film contains a certain amount of a crosslinking agent that has not reacted even after the crosslinking reaction has been completed. However, the amount of the remaining crosslinking agent is preferably 1.0% by mass or less and more preferably 0.5% by mass or less in the alignment film. In this way, even if the polarizing film is incorporated in a liquid crystal display device and used for a long time or left in a high temperature and high humidity atmosphere for a long time, the degree of polarization does not decrease.
The crosslinking agent is described in US Reissue Patent 23297. Boron compounds (eg, boric acid, borax) can also be used as a crosslinking agent.

As the dichroic dye, an azo dye, stilbene dye, pyrazolone dye, triphenylmethane dye, quinoline dye, oxazine dye, thiazine dye or anthraquinone dye is used. The dichroic dye is preferably water-soluble. The dichroic dye preferably has a hydrophilic substituent (eg, sulfo, amino, hydroxyl).
As an example of a dichroic dye, the compound as described in page 58 of the said technical number 2001-1745 is mentioned, for example.

  In order to increase the contrast ratio of the liquid crystal display device, the transmittance of the polarizing plate is preferably higher and the degree of polarization is preferably higher. The transmittance of the polarizing plate is preferably in the range of 30 to 50%, more preferably in the range of 35 to 50%, and most preferably in the range of 40 to 50% in light having a wavelength of 550 nm. . The degree of polarization is preferably in the range of 90 to 100%, more preferably in the range of 95 to 100%, and most preferably in the range of 99 to 100% in light having a wavelength of 550 nm.

<< Manufacture of elliptically polarizing plates >>
In the stretching method, the stretching ratio is preferably 2.5 to 30.0 times, and more preferably 3.0 to 10.0 times. Stretching can be performed by dry stretching in air. Moreover, you may implement wet extending | stretching in the state immersed in water. The stretch ratio of dry stretching is preferably 2.5 to 5.0 times, and the stretch ratio of wet stretching is preferably 3.0 to 10.0 times. The stretching step may be performed in several steps including oblique stretching. By dividing into several times, it is possible to stretch more uniformly even at high magnification. Before the oblique stretching, a slight stretching (a degree to prevent shrinkage in the width direction) may be performed horizontally or vertically. Stretching can be performed by performing tenter stretching in biaxial stretching in different steps. The biaxial stretching is the same as the stretching method performed in normal film formation. In biaxial stretching, stretching is performed at different speeds on the left and right, so that the thickness of the binder film before stretching must be different on the left and right. In casting film formation, the flow rate of the binder solution can be differentiated between the left and right sides by tapering the die.

  In the rubbing method, a rubbing treatment method widely adopted as a liquid crystal alignment treatment process of LCD can be applied. That is, orientation is obtained by rubbing the surface of the film in a certain direction using paper, gauze, felt, rubber, nylon, or polyester fiber. Generally, it is carried out by rubbing several times using a cloth in which fibers having a uniform length and thickness are planted on average. It is preferable to carry out using a rubbing roll in which the roundness, cylindricity, and deflection (eccentricity) of the roll itself are all 30 μm or less. The film wrap angle on the rubbing roll is preferably 0.1 to 90 °. However, as described in JP-A-8-160430, a stable rubbing treatment can be obtained by winding 360 ° or more.

  When rubbing a long film, the film is preferably transported at a speed of 1 to 100 m / min in a constant tension state by a transport device. The rubbing roll is preferably rotatable in the horizontal direction with respect to the film traveling direction for setting an arbitrary rubbing angle. It is preferable to select an appropriate rubbing angle in the range of 0 to 60 °.

It is preferable to dispose a polymer film on the surface of the linearly polarizing film opposite to the optically anisotropic layer (arrangement of optically anisotropic layer / polarizing film / polymer film).
It is also preferable that the polymer film is provided with an antireflection film having an outermost surface having antifouling properties and scratch resistance. Any conventionally known antireflection film can be used.

  The present invention will be described more specifically with reference to the following examples. The materials, reagents, amounts and ratios of substances, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples.

[Example 1]
(Preparation of cellulose acetate solution)
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acetate solution.

-----------------------------------
Cellulose acetate solution composition ----------------------------------
Cellulose acetate having an acetylation degree of 60.9% 100.0 parts by weight Triphenyl phosphate (plasticizer) 7.0 parts by weight Biphenyl diphenyl phosphate (plasticizer) 4.0 parts by weight The following dye 0.0006 parts by weight Methylene chloride ( First solvent) 402.0 parts by mass Methanol (second solvent) 60.0 parts by mass ---------------------------- -------

(Preparation of matting agent dispersion)
The following composition was charged into a disperser and stirred to disperse each component to prepare a matting agent dispersion.

-----------------------------------
Matting agent dispersion composition ----------------------------------
Silica particles having an average particle size of 16 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 2.0 parts by mass Methylene chloride (first solvent) 76.3 parts by mass Methanol (second solvent) 11.4 parts by mass Cellulose acetate solution 10.3 parts by mass ----------------------------------

(Preparation of retardation increasing agent solution)
The following composition was put into a mixing tank and stirred while warming to 30 ° C. to dissolve each component to prepare a retardation increasing agent solution.

-----------------------------------
Retardation raising agent solution composition -----------------------------------
The following retardation increasing agent 20.0 mass parts Methylene chloride (first solvent) 58.3 mass parts Methanol (second solvent) 8.7 mass parts Cellulose acetate solution 12.8 mass parts -------- ---------------------------

(Production of cellulose acetate film)
The cellulose acetate solution 94.75 parts by mass, the matting agent dispersion 1.30 parts by mass, and the retardation increasing agent solution 3.95 parts by mass were mixed after filtration and cast using a band casting machine. The mass ratio of the retardation increasing agent to cellulose acetate was 4.8%. A film having a residual solvent amount of 30% by mass was peeled from the band. At a temperature of 140 ° C., the film was transversely stretched at a stretch ratio of 28% using a tenter. After stretching, the stretch ratio was relaxed to 25% and held at 140 ° C. for 20 seconds. At this time, the residual solvent amount at the maximum widening point was 14% by mass. Thereafter, the clip was removed and dried at 130 ° C. for 45 minutes to produce a cellulose acetate film. The produced cellulose acetate film had a residual solvent amount of 0.2% by mass and a film thickness of 88 μm.

(Measurement of optical properties)
About the produced cellulose acetate film, Re retardation value was measured with the light of wavelength 632.8nm using the ellipsometer (M-150, JASCO Corporation make). Retardation values Re (40 °) and Re (−40 °) were measured with the in-plane slow axis as the tilt axis at 40 ° and −40 °. Using the film thickness and refractive index nx in the slow axis direction as parameters, the refractive index in the fast axis direction is fitted to these measured values Re (632.8 nm), Re (40 °), and Re (−40 °). ny and the refractive index nz in the thickness direction were obtained by calculation to determine the Rth retardation value. Further, the Re retardation value was measured with light having a wavelength of 400 nm and a wavelength of 550 nm, and α2 = Re (400 nm) / Re (550 nm) was calculated.

(Saponification treatment of cellulose acetate film)
One side of the produced cellulose acetate film was coated with 25 ml / m ^{2 of} 1.5 N potassium hydroxide in isopropyl alcohol, allowed to stand at 25 ° C. for 5 seconds, washed with running water for 10 seconds, and air at 25 ° C. The surface of the film was dried by spraying. In this way, only one surface of the cellulose acetate film was saponified.

(Formation of alignment film)
On one surface of a saponified cellulose acetate film (transparent support), a coating solution having the following composition was applied at 24 ml / m ² with a # 14 wire bar coater. Drying was performed with warm air of 60 ° C. for 60 seconds, and further with warm air of 90 ° C. for 150 seconds. Next, the formed film was rubbed in the direction of 45 ° with the stretching direction of the cellulose acetate film (transparent support) (substantially coincident with the slow axis).

--------------------------------
Alignment film coating solution composition --------------------------------
The following modified polyvinyl alcohol 20 parts by mass Water 360 parts by mass Methanol 120 parts by mass Glutaraldehyde (crosslinking agent) 2 parts by mass ----------------- ---------

(Formation of optically anisotropic layer)
A coating solution containing a discotic compound having the following composition was continuously applied onto the prepared alignment film with a # 3.2 wire bar. For drying the solvent of the coating solution and orientation ripening of the discotic compound, heating was performed with warm air at 100 ° C. for 30 seconds, and further with warm air at 130 ° C. for 60 seconds. Subsequently, the alignment of the liquid crystal compound was fixed by UV irradiation to form an optically anisotropic layer. Subsequently, the surface of the cellulose acetate film opposite to the surface on which the optically anisotropic layer was formed was continuously saponified to produce an optical compensation sheet.

-----------------------------------
Optically anisotropic layer coating composition ----------------------------------
The following discotic compound (1) 41.01 parts by mass Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 4.06 parts by mass Cellulose acetate butyrate (CAB551-0.2, 0.34 parts by mass Cellulose acetate butyrate (CAB531-1, manufactured by Eastman Chemical Co.) 0.11 parts by mass The following fluoroaliphatic group-containing polymer 1 0.03 parts by mass The following fluoroaliphatic group-containing Polymer 2 20.23 parts by mass Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 1.35 parts by mass Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.45 parts by mass Methyl ethyl ketone 107 parts by mass ------------------------ ---------

An optically anisotropic layer was formed in the same manner as described above except that the transparent support was changed to a glass plate. Using an ellipsometer (M-150, manufactured by JASCO Corporation), the Re retardation value of the optically anisotropic layer was measured with light having a wavelength of 632.8 nm. Retardation Re (40) and Re (-40) were measured with the in-plane slow axis as the tilt axis at 40 ° and -40 °.
Furthermore, the Re retardation value was measured at a wavelength of 400 nm. The results are Re (λ: 632.8 nm) = 38 nm, Re (40) /Re=1.76, and Re (−40) /Re=0.46, Re (400) / Re (550) = 1.06. Met.

  The white luminance viewing angle was measured for a polar angle range (angle of inclination from the normal) of 50%. The result was 120 °.

(Production of elliptically polarizing plate)
A polarizing film was prepared by adsorbing iodine to a stretched polyvinyl alcohol film.
Next, the transparent support side of the produced optical compensation sheet was attached to one side of the polarizing film using a polyvinyl alcohol-based adhesive. The slow axis of the transparent support and the transmission axis of the polarizing film were arranged in parallel.
A commercially available cellulose triacetate film (Fujitac TD80U, manufactured by Fuji Film Co., Ltd.) was saponified in the same manner as the transparent support, and using a polyvinyl alcohol adhesive, the opposite side of the polarizing film (the side on which no optical compensation sheet was attached) ).
In this manner, an elliptically polarizing plate was produced.

(Production of ECB alignment liquid crystal cell)
A polyimide film was provided as an alignment film on a glass substrate with an ITO electrode, and the alignment film was rubbed. The rubbing direction was a 45 ° direction in the screen. The obtained two glass substrates were bonded to each other so that the rubbing directions were parallel to each other, and the cell gap was set to 3.5 μm. Dielectric anisotropy Δε between the upper and lower substrates is positive, refractive index anisotropy, Δn = 0.0939 (450 nm, 20 ° C.), 0.0854 (589 nm, 20 ° C.), 0.0853 (633 nm, 20 ° C), a liquid crystal having Δε = + 8.5 (for example, MLC-9100 manufactured by Merck & Co., Inc.) was used. Here, the brightness at the time of white display changes depending on the magnitude of the product Δn · d of the thickness d and the refractive index anisotropy Δn. For this reason, in order to obtain the maximum brightness, it is preferably set to be in the range of 0.2 to 0.4 μm. The polarizing plate absorption axis intersects the liquid crystal cell alignment direction (rubbing direction) at approximately 45 °, and the crossing angle between the upper and lower polarizing plate absorption axes is approximately 90 ° crossed Nicol.

(Production of color filter)
One transparent glass substrate on which a transcalar filter manufactured by Fujifilm was formed by the method described in Examples of JP-A-10-221518 was used. The surface roughness of the transcalar filter used was 0.2 microns or less.
At this time, the thickness of the liquid crystal layer of the green pixel was set to 3.5 μm and the thickness of the liquid crystal layer of the red pixel was set to 3.8 μm by changing the thickness of the blue, green, and red color filters. The retardation of the liquid crystal layer of each pixel of green and red was Δn (λ1) × d1 = 0.3 μm and Δn (λ2) × d2 = 0.295 μm (where λ1 = 589 nm, λ2 = 633 nm), respectively. . In addition, when the retardation of each color filter was measured using an ellipsometer (M-150, manufactured by JASCO Corporation), | Re (630 nm) | = 0.2 nm, | Rth (630 nm) | = 9. 3 nm, | Re (400) −Re (700) | = 1.9 nm, | Rth (400) −Rth (700) | = 4.3 nm.

(Optical performance of liquid crystal display)
The manufactured liquid crystal display device is placed on a field sequential backlight composed of RGB three-color LED light sources, a white display voltage of 2 V and a black display voltage of 5 V are applied to the liquid crystal cell, and a luminance meter (SR-3 manufactured by Topcon Corporation) is used. Then, the contrast ratio (ratio between white display transmittance and black display transmittance) on the front of the panel and the black transmittance at an azimuth angle of 0 to 360 ° at 5 ° intervals at a polar angle of 60 ° are measured, and the maximum transmittance is measured. Is shown in Table 1.
From the results in the table, there was little leakage light in blue, green and red displays, and there was little coloring when observed from an oblique direction.

[Example 2]
In Example 1, the thicknesses of the blue, green and red color filters were further changed to change the retardation of each color. The thickness of the liquid crystal layer of the blue pixel was 3.3 μm, green was 3.5 μm, and red was 3.8 μm. The retardation of the liquid crystal layer of each pixel is Δn (λ ₁ ) × d ₁ = 0.31 μm, Δn (λ ₂ ) × d ₂ = 0.30 μm, and Δn (λ ₃ ) × d ₃ = 0.295 μm ( However, λ ₁ = 450 nm, λ ₂ = 589 nm, λ ₃ = 633 nm).
Compared with the liquid crystal display device of Example 1, the liquid crystal display device of this example further decreased the oblique transmittance in each color, and the coloring was improved.

[Comparative Example 1]
In Example 1, measurement was performed without stacking the color filters, and the results are shown in Table 1. From the table, the transmittance of red was particularly large, and it was colored red.

[Example 3: Production of VA mode liquid crystal display device of first aspect]
(Production of Cellulose Acylate Films 101 to 105 for the First Optically Anisotropic Layer)
Each component was mixed so that the ratio described in Table 2 was obtained, thereby preparing a cellulose acylate solution. Each cellulose acylate solution was cast using a band casting machine, and the obtained web was peeled from the band and then stretched. After extending | stretching, it dried and produced the cellulose acylate films 101-105 of the thickness as described in Table 2, respectively.

  About each produced film, three-dimensional birefringence measurement is performed at wavelengths of 450 nm, 550 nm, and 630 nm using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments) by the above method, and in-plane retardation Re and The retardation Rth in the film thickness direction obtained by measuring Re at different tilt angles was determined. Table 2 shows values of Rth (550), Rth (450) / Re (550), and Rth (630) -Re (550), respectively. From the results shown in Table 2, it can be understood that all of the produced cellulose acylate films 101 to 105 satisfy the optical characteristics as the first optical anisotropic layer, and Rth is forward-dispersible.

(Preparation of cellulose acylate film 201 for second optically anisotropic layer)
The cellulose acylate solution 201 was prepared by mixing the components so that the proportions described below were obtained. Each cellulose acylate solution was cast using a band casting machine, the obtained web was peeled from the band, and then stretched under the following conditions. The TD direction means a direction orthogonal to the transport direction. After stretching, the cellulose acylate film 201 was obtained by drying.
Cellulose acylate solution 201
Cellulose acylate (acyl group substitution degree 2.86) 100 parts by weight Triphenyl phosphate 7 parts by weight Biphenyl phosphate 5 parts by weight Re expression agent 1 9 parts by weight Methylene chloride 457 parts by weight Methanol 94 parts by weight

Re expression agent 1

  Using the automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments), the produced film (thickness: 80 μm) was measured for three-dimensional birefringence at wavelengths of 450 nm, 550 nm, and 630 nm. The retardation Rth in the film thickness direction obtained by measuring Re by changing the foundation Re and the inclination angle was obtained. The produced cellulose acylate film has Re (550) of 105 nm, Rth (550) of 120 nm, Re (450) / Re (550) of 0.85, and Re (630) / Re (550) of 1. 0.04, Rth (450) / Rth (550) is 0.83, and Rth (630) / Rth (550) is 1.06, which satisfies the optical characteristics as the second optically anisotropic layer. In addition, it was found that Re and Rth are inversely dispersible.

(Preparation of Display Surface Side Polarizing Plates 101 to 105 and Backlight Side Polarizing Plate 201)
The surface of each polymer film 101-105 and 201 produced above was alkali saponified. It was immersed in a 1.5 N aqueous sodium hydroxide solution at 55 ° C. for 2 minutes, washed in a water bath at room temperature, and neutralized with 0.1 N sulfuric acid at 30 ° C. Again, it was washed in a water bath at room temperature and further dried with hot air at 100 ° C. Subsequently, a roll-shaped polyvinyl alcohol film having a thickness of 80 μm was continuously stretched 5 times in an iodine aqueous solution and dried to obtain a polarizing film having a thickness of 20 μm. Prepare each of the above-mentioned alkali-saponified polymer films 101 to 105 and 201 and the same alkali-saponified Fujitac TD80UL (manufactured by Fujifilm) using a 3% aqueous solution of polyvinyl alcohol (Kuraray PVA-117H) as an adhesive. The polarizing films 101 to 105 and 201 each having a polymer film and a TD80UL as a protective film for the polarizing film are obtained by attaching the polarizing films so that the saponified surfaces are on the polarizing film side. It was.

Liquid crystal display devices 301 to 304 having the same configuration as in FIG. Each of the polarizing plates 101 to 105 produced as described above is incorporated as a polarizing plate on the display surface side (polarizing plate P1 ′ in FIG. 2), and the polarizing plate 201 produced above is incorporated into the backlight side polarizing plate (in FIG. 2). It was incorporated as a polarizing plate P2 ′). Further, the RGB color filter shown in FIG. 3B is formed on the inner surface of the substrate 1, and d _B = 3.3 μm, d _G = 3.5 μm, d _R = 3.8 μm. 'S satisfied the following formula (2).
Formula (2) d _B <d _G <d _R

For each of the liquid crystal display devices produced and color shift in the black Δu'v '(= √ (u'max- u'min) 2 + (v'max-v'min) 2) was measured. Here, u′max (v′max) is the maximum u ′ (v ′) of 0 to 360 degrees, and u′min (v′min) is the minimum u ′ (v ′) of 0 to 360 degrees. It is. The results are shown in Table 3.

[Comparative Example 2]
A liquid crystal display device having the same configuration as in Example 3 except that polarizing plates 103 to 105 are used as the display surface side polarizing plates, and a substrate having an RGB color filter with a uniform thickness formed on the inner surface is used as the substrate 1. 303 ′ to 305 ′ were prepared, and the color change Δu′v ′ during black display was measured for each. The results are also shown in Table 3 below.

  From the results shown in Table 3, by changing the thickness of the RGB color filter, Example 3 using the VA mode liquid crystal cell satisfying the above formula (2) has an RGB color filter with a uniform thickness. It can be understood that the color change is reduced as compared with Comparative Example 2 using a liquid crystal cell. In particular, in the VA mode liquid crystal display device of Example 3, Rth (630) -Rth (550) serving as an index of Rth wavelength dispersion of the first optical anisotropic layer is in the range of −30 to 0 nm. While the effect of reducing the color change was confirmed, in the VA mode liquid crystal display device of the comparative example, Rth (630) −Rth (550) is smaller than −40 nm, that is, extreme forward dispersion for Rth. It was found that the effect of reducing the color change similar to that of the example of the present invention can be obtained for the first time by using the optically anisotropic layer showing

[Example 4: Production of VA mode liquid crystal display device of first aspect]
(Preparation of cellulose acylate film 202 for second optically anisotropic layer)
(Preparation of cellulose acylate solution)
The following composition was put into a mixing tank and stirred at 80 ° C. for 3 hours to dissolve each component to prepare a cellulose acylate solution.
-----------------------------------
Cellulose acylate solution composition ----------------------------------
Cellulose acylate having an acetyl substitution degree of 2.94 100 parts by weight Triphenyl phosphate (plasticizer) 4 parts by weight Biphenyl diphenyl phosphate (plasticizer) 3 parts by weight The following dye 6 parts by weight Methylene chloride (first solvent) 402 parts by weight Methanol (Second solvent) 60 parts by mass ----------------------------------

(Preparation of matting agent dispersion)
The following composition was charged into a disperser and stirred to disperse each component to prepare a matting agent dispersion.

-----------------------------------
Matting agent dispersion composition ----------------------------------
Silica particles having an average particle diameter of 16 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 2.0 parts by mass Methylene chloride (first solvent) 76.3 parts by mass Methanol (second solvent) 11.4 parts by mass Cellulose acylate Solution 10.3 parts by mass ----------------------------------

(Preparation of retardation increasing agent solution)
The following composition was put into a mixing tank and stirred while warming to 30 ° C. to dissolve each component to prepare a retardation increasing agent solution.

-----------------------------------
Retardation raising agent solution composition -----------------------------------
The following retardation developing agent F-1 12 parts by mass The following retardation developing agent F-2 10 parts by mass Methylene chloride (first solvent) 58 parts by mass Methanol (second solvent) 8 parts by mass Cellulose acylate solution 12 parts by mass -----------------------------------

(Film formation)
94.8 parts by mass of the cellulose acylate solution, 1.3 parts by mass of the matting agent dispersion, and 8.4 parts by mass of the retardation increasing agent solution were mixed after filtration, and cast using a band casting machine. The mass ratio of retardation developer F-1 to cellulose acylate was 6.0%, and the mass ratio of retardation developer F-2 to cellulose acylate was 5.0%. A film having a residual solvent amount of 30% by mass was peeled from the band. At a temperature of 140 ° C., the film was transversely stretched at a stretch ratio of 25% using a tenter, and after stretching, the stretch ratio was relaxed to 25% and held at 140 ° C. for 20 seconds. Thereafter, the clip was removed and dried at 130 ° C. for 25 minutes to produce a cellulose acylate film. The produced cellulose acylate film had a residual solvent amount of 0.2% by mass and a film thickness of 55 μm.

(Optical measurement evaluation of cellulose acylate film 202)
The produced optical film 202 (thickness 55 μm) is subjected to three-dimensional birefringence measurement at wavelengths of 450 nm, 550 nm and 630 nm using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments), and in-plane retardation The retardation Rth in the film thickness direction obtained by measuring Re by changing Re and the tilt angle was obtained. The produced cellulose acylate film 202 has Re (550) of 100 nm, Rth (550) of 125 nm, Re (450) / Re (550) of 0.84, and Re (630) / Re (550) of 1.04, Rth (450) / Rth (550) is 0.82, and Rth (630) / Rth (550) is 1.06, which satisfies the optical characteristics as the second optically anisotropic layer. In addition, Re and Rth were found to be inversely dispersible.

(Polarizing plate processing and production of liquid crystal display devices)
A polarizing plate 202 was produced from the cellulose acylate film 202 produced in the same manner as in the cellulose acylate film 201 produced in Example 3. Using this and the polarizing plate 101 produced in Example 3, a liquid crystal display device 306 was produced in the same manner as in Example 3 with the configuration of FIG.

(Measurement of display performance)
By the same operation as that performed in Example 3, for the liquid crystal display device 306 produced above, the color change Δu′v ′ (= √ (u′max−u′min) ² + (v 'max-v'min) ² ) was measured respectively. Here, u′max (v′max) is the maximum u ′ (v ′) of 0 to 360 degrees, and u′min (v′min) is the minimum u ′ (v ′) of 0 to 360 degrees. It is. The results are shown in Table 4.

[Comparative Example 4]
In the production of the liquid crystal display device 306 of the fourth embodiment, a liquid crystal display device 306 ′ having the same configuration as the liquid crystal display device 306 is used except that a substrate having an RGB color filter with a uniform thickness formed on the inner surface is used as the substrate 1. The color change Δu′v ′ during black display was measured in the same manner. The results are also shown in Table 4 below.

[Example 5: Production of VA mode liquid crystal display device of second aspect]
(Preparation of optical anisotropic layer film 501)
A commercially available norbornene-based polymer film “ZEONOR” (manufactured by Nippon Zeon Co., Ltd.) was fixed at 140 ° C. and stretched 30% in the transverse direction to produce a norbornene-based film 501.

(Preparation of optical anisotropic layer film 502)
The cellulose acylate solution was prepared by mixing each component so as to have the ratio described below. Each cellulose acylate solution was cast using a band casting machine, the obtained web was peeled from the band, and then stretched 25% in the TD direction under the condition of 140 ° C. The TD direction means a direction perpendicular to the transport direction. After stretching, the film was dried to obtain a 40 μm optical film 502.
(Cellulose acylate solution)
Cellulose acylate having an acetyl substitution degree of 1.54 and a propionyl substitution degree of 0.84
100 parts by mass The following additives K-1 5 parts by mass The following additives K-2 4 parts by mass Methylene chloride 416 parts by mass Ethanol 79 parts by mass

(Preparation of optical anisotropic layer film 503)
The cellulose acylate solution was prepared by mixing each component so as to have the ratio described below. Each cellulose acylate solution was cast using a band casting machine, and the obtained web was peeled from the band. Thereafter, the cellulose acylate solution was stretched 25% in the TD direction under the condition of 120 ° C., and then dried to be 55 μm. An optical film 503 was obtained.
(Cellulose acylate solution)
Cellulose acylate having an acetyl group substitution degree of 2.81 100 parts by mass The following retardation increasing agent 4 parts by mass Triphenyl phosphate (plasticizer) 7 parts by mass Biphenyl diphenyl phosphate (plasticizer) 5 parts by mass Methylene chloride 430 parts by mass Methanol 64 Parts by mass

(Preparation of optical anisotropic layer film 504)
The cellulose acylate solution was prepared by mixing each component so as to have the ratio described below. Each cellulose acylate solution was cast using a band casting machine, and the obtained web was peeled from the band. After that, it was stretched by 20% in the TD direction under the condition of 140 ° C., and then dried to be 50 μm. An optical film 504 was obtained.
(Cellulose acylate solution)
Cellulose acylate having an acetyl group substitution degree of 2.86
100 parts by mass The following retardation developer F-1 2 parts by mass The following retardation developer F-2 6 parts by mass Triphenyl phosphate 3 parts by mass Diphenyl phosphate 2 parts by mass Methylene chloride 418 parts by mass Methanol 62 parts by mass

  The optical films 501 to 504 produced above were measured for three-dimensional birefringence at wavelengths of 450 nm, 550 nm, and 630 nm using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments Co., Ltd.). The retardation Rth in the film thickness direction obtained by measuring Re by changing the foundation Re and the tilt angle was determined. The results are shown in Table 5. As shown in Table 5, films 501 to 504 and 109 all satisfied the above formulas (XV) and (XVI).

(Polarizing plate processing and production of liquid crystal display devices)
Polarizing plates 501 to 504 were produced in the same manner as in Example 3 except that the produced optical films 501 to 504 were used instead of the cellulose acylate film 201.
A VA mode liquid crystal display device having the same configuration as that shown in FIG. 8 was prepared using two of the produced polarizing plates. Specifically, as the polarizing plates P1 ″ and P2 ″ in FIG. 8, liquid crystal display devices 501 to 504 were respectively manufactured using the above-prepared polarizing plates 501 to 504. When disposing the polarizing plates, the films 501 to 504 are disposed on the liquid crystal cell 5 ′ side, that is, the films 501 to 504 are disposed as the optically anisotropic layers 20a and 20b in FIG. .
The liquid crystal cells LC ′ of the liquid crystal display devices 501 to 504 are multi-gap liquid crystal cells, and the thicknesses of the B, G, and R regions of the liquid crystal layer 5 ′ are set as shown in Table 6 below. The thickness of the liquid crystal layer was adjusted according to the thickness of the color filter as shown in Table 6 below.

(Measurement of display performance)
Regarding the liquid crystal display devices 501 to 504 manufactured as described above, the color change Δu′v ′ (= √ (u′max−u′min) ² + (v′max−) during black display is performed in the same manner as in Example 3. v′min) ² ) was measured respectively. Here, u′max (v′max) is the maximum u ′ (v ′) of 0 to 360 degrees, and u′min (v′min) is the minimum u ′ (v ′) of 0 to 360 degrees. It is. The results are shown in Table 7.

  From the results shown in Table 7, Example 5 using the VA mode liquid crystal cell satisfying the above formula (2) by changing the thickness of the RGB color filter has an RGB color filter with a uniform thickness. As compared with Comparative Example 5 using a liquid crystal cell, it can be understood that the color change in the oblique direction can be reduced without limitation on the material of the optically anisotropic layer, the wavelength dispersibility of the retardation, and the like.

It is the schematic of an example of the liquid crystal display device of this invention. It is the schematic of the other example of the liquid crystal display device of this invention. FIG. 3 is a schematic cross-sectional view schematically showing an enlarged part of a cross section of a liquid crystal cell in the example of the liquid crystal display device shown in FIG. 2. FIG. 3 is a diagram used for explaining an example of the optical compensation mechanism on the Poincare sphere for the example of the liquid crystal display device shown in FIG. 2. FIG. 3 is a diagram used for explaining an example of the optical compensation mechanism on the Poincare sphere for the example of the liquid crystal display device shown in FIG. 2. FIG. 3 is a diagram used for explaining an example of the optical compensation mechanism on the Poincare sphere for the example of the liquid crystal display device shown in FIG. 2. FIG. 3 is a diagram used for explaining an example of the optical compensation mechanism on the Poincare sphere for the example of the liquid crystal display device shown in FIG. 2. It is the schematic of the other example of the liquid crystal display device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal cell upper substrate 2 Upper substrate Liquid crystal alignment rubbing direction 3 Liquid crystal cell lower substrate 4 Lower substrate Liquid crystal alignment rubbing direction 5, 5 ′ Liquid crystal layer (liquid crystal molecule)
6a, 6b Polarizing plate outer protective film 7a, 7b Polarizing plate outer protective film slow axis 8a, 8b Polarizing film 9a, 9b Polarizing film absorption axis 10a, 10b Transparent support 11a, 11b of optically anisotropic layer Slow axis 12a, 12b Optical anisotropic layer 13a, 13b Rubbing direction 14 for aligning liquid crystal molecules when forming optical anisotropic layer 14 First optical anisotropic layer 16 Second optical anisotropic layer 17 Slow axes 20a, 20b of the second optical anisotropic layer Optical anisotropic layers 21a, 21b Slow axes P1, P1 ', P1 ", P2, P2', P2" of the optical anisotropic layer Polarizing plate LC LC 'liquid crystal cell

Claims (26)

A pair of at least a liquid crystal cell and a polarizing plate (first polarizing plate) disposed on at least one outside of the liquid crystal cell, the liquid crystal cell having at least an electrode on one side. A substrate and a liquid crystal layer sandwiched between the substrates, including at least three pixel regions, and color filters having wavelength selectivity in transmittance are disposed on the three pixel regions; Λ ₁ , λ ₂ , and λ ₃ (unit: nm) in ascending order of the dominant wavelength that takes the maximum transmittance of the color filter provided in the pixel region, and the thickness of the liquid crystal layer in each of these pixel regions Where d ₁ , d ₂ , and d ₃ (unit: nm) are sequentially satisfied, the following formula (1) is satisfied:
Equation _{(1): d 2 <d} 3. The liquid crystal display device according to claim 1, further satisfying the following formula (2):
Equation _{(2): d 1 <d} 2 <d 3. 2. The Rth of color filters arranged in at least two pixel regions among the retardations (Rth) in the thickness direction of the color filters arranged on the three pixel regions are different from each other. Or a liquid crystal display device according to 2; The liquid crystal display device according to claim 1, wherein the color filter satisfies the following formulas (I) and (II):
(I) | Re (630) | ≦ 10 and | Rth (630) | ≦ 40
(II) | Re (400) −Re (700) | ≦ 10 and | Rth (400) −Rth (700) | ≦ 35
In the above formulas (I) and (II), Re (λ) represents the in-plane retardation value (nm) at the wavelength λnm, and Rth (λ) represents the retardation value (nm) in the thickness direction at the wavelength λnm. To express. The first optically anisotropic layer satisfying the following formulas (III) and (IV), and a second optically anisotropic layer having at least one optical axis in the plane are further included. The liquid crystal display device according to any one of 1 to 4:
Formula (III) 0 nm <Rth (550) ≦ 300 nm
Formula (IV) Rth (550) / Re (550)> 10. The liquid crystal display device according to claim 5, wherein the first optically anisotropic layer satisfies the following formulas (V) to (VII):
Formula (V) Rth (450) / Rth (550) ≧ 1
Formula (VI) Rth (630) / Rth (550) ≦ 1
Formula (VII) −30 nm ≦ Rth (630) −Rth (450) ≦ 0 nm. The liquid crystal display device according to claim 5, wherein the second optically anisotropic layer satisfies the following formulas (VIII) and (IX):
Formula (VIII) 55 nm ≦ Re (550) ≦ 315 nm
Formula (IX) 0 nm ≦ Rth (550) ≦ 275 nm. An optical anisotropic layer A is provided between the first polarizing plate and the liquid crystal cell, the optical anisotropic layer A satisfies the following formulas (XV) and (VXI), and the optical anisotropic The projected axis is parallel to the absorption axis when the slow axis of the conductive layer A is projected on the same plane as the absorption axis of the first polarizing plate. Liquid crystal display device according to item:
(XV) 30 nm ≦ Re (550) ≦ 80 nm
(XVI) 75 nm ≦ Rth (550) ≦ 155 nm. A second polarizing plate that is disposed with the liquid crystal cell in between the first polarizing plate and has an absorption axis that is orthogonal to the absorption axis of the first polarizing plate. An optically anisotropic layer B is provided between the liquid crystal cell, the optically anisotropic layer B satisfies the formulas (XV) and (XVI), and the slow axis of the optically anisotropic layer B The liquid crystal display device according to claim 8, wherein the projection axis is parallel to the absorption axis when projected onto the same plane as the absorption axis of the second polarizing plate. The retardation Rth (550) in the thickness direction at a wavelength of 550 nm of each of the optically anisotropic layers A and B and Δn (550) × d of the liquid crystal layer satisfy the relationship of the following formula (XVII): The liquid crystal display device according to claim 9:
(XVII) 0.7 ≦ (2 × Rth (550)) / Δn (550) × d ≦ 1.3
Here, Δn (550) is the refractive index anisotropy in the thickness direction of the liquid crystal layer at 550 nm, and d is the average thickness (nm) of the liquid crystal layer. 11. At least one of the optically anisotropic layers contains at least one kind of polymer and at least one kind of additive, and at least one kind of the additive is a liquid crystalline compound. The liquid crystal display device according to any one of the above. The liquid crystal according to claim 11, wherein the liquid crystal compound contains at least one liquid crystal compound in an amount of 0.1 to 30% by mass, and a mass ratio of the liquid crystal compound to all additives is 40 to 100% by mass. Display device. 12. The liquid crystal compound of 2 or more types is contained in an amount of 0.1 to 30% by mass, and the mass ratio of the two or more types of liquid crystal compounds to all additives is 50 to 100% by mass. Or the liquid crystal display device of 12. 14. The liquid crystal compound according to claim 11, wherein the liquid crystal compound contains at least one compound represented by the following formula (A) and a rod-shaped compound represented by the following formula (a). The liquid crystal display device described.

(In the formula, L ¹ and L ² each independently represent a single bond or a divalent linking group. A ¹ and A ² each independently represent —O—, —NR— (R represents a hydrogen atom or a substituent). Represents a group selected from the group consisting of —S— and —CO—, and R ¹ , R ² , and R ³ each independently represents a substituent.
X represents a group 6, 5 or 4 atom. n represents an integer of 0 to 2. )
Formula (a): Ar ¹ -L ¹² -XL ¹³ -Ar ²
In the general formula (a), Ar ¹ and Ar ² are each independently an aromatic group; L ¹² and L ¹³ are each independently an —O—CO— or —CO—O— group; X Is a 1,4-cyclohexylene group, a vinylene group or an ethynylene group. The liquid crystal display device according to claim 5, wherein at least one of the optically anisotropic layers is made of a norbornene polymer film. The liquid crystal display device according to claim 5, wherein at least one of the optically anisotropic layers is made of a cellulose acylate film. The liquid crystal display device according to claim 16, wherein the acyl substituent of cellulose acylate contained as a main component in the cellulose acylate film is at least one selected from acetyl, propionyl and butyryl. 18. The liquid crystal display device according to claim 5, wherein at least one of the optically anisotropic layers contains at least one Rth enhancer. 19. The liquid crystal display device according to claim 18, wherein the Rth enhancer contains at least one compound having an absorption maximum at 250 nm to 380 nm. 20. The liquid crystal display device according to claim 18, wherein the Rth enhancer contains at least one compound represented by the following formula (I).

(Wherein, X ¹ is a single bond, -NR ⁴ -, - O-or a S-; X ² represents a single bond, -NR ⁵ -, - O-or a S-; X ³ is A single bond, —NR ⁶ —, —O—, or S—, and R ¹ , R ² , and R ³ are each independently an alkyl group, an alkenyl group, an aromatic ring group, or a heterocyclic group. R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group. 21. The liquid crystal display device according to claim 20, comprising 0.1 to 30% by mass of at least one compound represented by the formula (I). The thickness of the said optically anisotropic layer is 30-200 micrometers, The liquid crystal display device of any one of Claims 5-21 characterized by the above-mentioned. 23. The parallel alignment type ECB mode, wherein the alignment of liquid crystal molecules changes in a direction perpendicular to the substrate surface by application of an electric field, and the transmittance of the liquid crystal layer decreases. A liquid crystal display device according to 1. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is in a bend alignment display mode. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is in a TN display mode. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is in a VA display mode.

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