JP7165491B2 - Optical film and its manufacturing method - Google Patents

Description

The present invention relates to an optical film and its manufacturing method.

Optical films such as polarizing plates and retardation plates are used in flat panel displays (FPDs). A retardation plate is required to have uniform phase conversion over the entire visible light range. A reverse wavelength dispersive retardation film is disclosed.

Japanese translation of PCT publication No. 2010-537955 JP 2015-57646 A

In recent years, with the evolution of flat panel displays, there has been a demand for clear black display when viewed from any direction. Accordingly, it has become clear that the horizontal or vertical optical wavelength dispersion control alone is insufficient.

The present invention includes the following inventions.

[1] An optical film having a first retardation layer and a second retardation layer and satisfying the following formulas (1) and (2).
0.4≦Nz(450)≦0.6 (1)
0.4≦Nz(550)≦0.6 (2)
[In the formula, Nz (450) represents the Nz coefficient of the optical film for light with a wavelength λ = 450 nm, Nz (550) represents the Nz coefficient of the optical film for light with a wavelength λ = 550 nm, and the wavelength λ (nm) The Nz coefficient Nz(λ) of the optical film for light is Nz(λ)=(nx(λ)−nz(λ))/(nx(λ)−ny(λ))
is indicated by nx(λ) represents the principal refractive index in the direction parallel to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the optical film. ny(λ) is the refraction in the refractive index ellipsoid formed by the optical film in a direction parallel to the film plane and orthogonal to the direction of nx(λ) for light of wavelength λ (nm) represents a rate. nz(λ) represents the refractive index of the refractive index ellipsoid formed by the optical film in the direction perpendicular to the plane of the film for light of wavelength λ (nm). ]

[2] The first retardation layer is
In the range of wavelength λ = 400 to 700 nm in the refractive index ellipsoid formed by the first retardation layer,
nx1(λ)>ny1(λ)≈nz1(λ)
[In the formula, nx1(λ) represents the principal refractive index in the direction parallel to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the first retardation layer. ny1 (λ) is a wavelength λ (nm) in a direction parallel to the film plane and perpendicular to the direction of the nx1 (λ) in the refractive index ellipsoid formed by the first retardation layer represents the refractive index for light. nz1(λ) represents the refractive index in the direction perpendicular to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the first retardation layer. ]
have a relationship of
The optical film of [1] above, which satisfies the relationships of the following formulas (3) and (4).
Re1(450)/Re1(550)≤1.00 (3)
1.00≤Re1(650)/Re1(550) (4)
[In the formula, Re1 (450) is the in-plane retardation value of the first retardation layer for light with a wavelength λ = 450 nm, and Re1 (550) is the in-plane position of the first retardation layer for light with a wavelength λ = 550 nm. Re1(650) indicates the in-plane retardation value of the first retardation layer for light with a wavelength λ=650 nm, and Re1(λ )teeth,
Re1(λ)=(nx1(λ)−ny1(λ))×d1
is represented by Here, d1 represents the thickness of the first retardation layer. ]

[3] The second retardation layer is
In the range of wavelength λ = 400 to 700 nm in the refractive index ellipsoid formed by the second retardation layer,
nz2(λ)>nx2(λ)≈ny2(λ)
[In the formula, nz2(λ) represents the refractive index in the direction perpendicular to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the second retardation layer. In the refractive index ellipsoid formed by the second retardation layer, nx2(λ) represents the maximum refractive index in the direction parallel to the film plane for light of wavelength λ (nm). ny2 (λ) is parallel to the film plane in the refractive index ellipsoid formed by the second retardation layer, and for light with a wavelength λ (nm) in a direction perpendicular to the direction of nx2 Represents refractive index. However, when nx2(λ)=ny2(λ), nx2(λ) represents the refractive index in any direction parallel to the film plane. ]
have a relationship of
The optical film of [1] or [2] above, which satisfies the relationships of the following formulas (5) and (6).
Rth2(450)/Rth2(550)≤1.00 (5)
1.00≦Rth2(650)/Rth2(550) (6)
[In the formula, Rth2 (450) is the retardation value in the thickness direction for light with a wavelength λ = 450 nm, and Rth2 (550) is the retardation value in the thickness direction of the second retardation layer for light with a wavelength λ = 550 nm. , Rth2 (650) represent the retardation value in the thickness direction of the second retardation layer for light with a wavelength of 650 nm, and the retardation value in the thickness direction of the second retardation layer for light with a wavelength λ (nm). (λ) is
Rth2(λ)=[(nx2(λ)+ny2(λ))/2−nz2(λ)]×d2
is represented by Here, in the refractive index ellipsoid formed by the second retardation layer, nz2 (λ) represents the principal refractive index in the direction perpendicular to the film plane at the wavelength λ (nm), ((nx2 (λ) + ny2 (λ))/2) represents the average refractive index in the plane of the film at the wavelength λ (nm). d2 represents the thickness of the second retardation layer. ]

[4] The optical film as described in any one of [1] to [3] above, wherein the first retardation layer further satisfies the following formula (7).
120nm≦Re1(550)≦170nm (7)
[In the formula, Re1 (550) represents the in-plane retardation value of the first retardation layer for light with a wavelength λ of 550 nm. ]

[5] The optical film as described in any one of [1] to [4] above, wherein the second retardation layer further has optical properties represented by formula (9).
−100 nm≦Rth2(550)≦−50 nm (8)
[In the formula, Rth2(550) represents a retardation value in the thickness direction of the second retardation layer with respect to light having a wavelength λ of 550 nm. ]

[6] The optical film as described in any one of [1] to [5] above, wherein the second retardation layer is a film comprising a coating layer formed by polymerizing the polymerizable liquid crystal in an oriented state.

[7] The optical film as described in any one of [1] to [6] above, wherein the first retardation layer is a film comprising a coating layer formed by polymerizing the polymerizable liquid crystal in an oriented state.

[8] The optical film as described in any one of [1] to [7] above, wherein the second retardation layer has a thickness of 5 μm or less.

[9] The optical film as described in any one of [1] to [8] above, wherein the first retardation layer has a thickness of 5 μm or less.

[10] Any one of the above [1] to [9], wherein the first retardation layer and the second retardation layer are coating layers formed by mainly polymerizing the same polymerizable liquid crystal compound. optical film.

[11] An elliptically polarizing plate with an optical compensation function, comprising the optical film according to any one of [1] to [10] above and a polarizing plate.

[12] The absorption axis of the polarizing plate and the slow axis of the first retardation layer have a relationship of 45±5° or 135±5° in the plane of the film, and the absorption axis of the polarizing plate and the first The elliptically polarizing plate with optical compensation function according to the above [11], wherein the slow axis of the retardation layer and the slow axis of the second retardation layer are perpendicular to the film surface in the vertical direction.

[13] The above-described [11] or [12], which is an optical layered body in which a polarizing plate, an adhesive layer, a first retardation layer, an adhesive layer, and a second retardation layer are formed in this order. Elliptical polarizer with optical compensation function.

[14] The above-described [11] or [12], which is an optical layered body in which a polarizing plate, an adhesive layer, a second retardation layer, an adhesive layer, and a first retardation layer are formed in this order. Elliptical polarizer with optical compensation function.

An organic EL display device comprising the elliptically polarizing plate with an optical compensation function according to any one of [11] to [14] above.

A method for producing an elliptically polarizing plate with an optical compensation function according to any one of [11] to [14] with an optical compensation function including all of the following steps.
(Step 1-A) A step of applying a polymerizable liquid crystal compound on a substrate on which a horizontal alignment film is formed, and then polymerizing the compound in a horizontally aligned state to form a retardation layer;
(Step 1-B) A step of forming a second retardation layer by coating a polymerizable liquid crystal compound on a base material on which a vertical alignment film is formed and then polymerizing the compound in a vertically aligned state;
(Step 2) A step of transferring the liquid crystal polymer of the first retardation layer and the liquid crystal polymer of the second retardation layer from the substrate via an adhesive and laminating them on the polarizing plate.

According to the present invention, a novel optical film whose optical refractive index is controlled in three-dimensional directions with respect to the entire visible light range and all viewing directions, and a method for producing the same are provided. Further, by using this optical film, a liquid crystal display device and an organic EL display device are provided which enable clear display.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. It should be noted that the scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the gist of the present invention.

The optical film of the present invention comprises a first retardation layer and a second retardation layer. The first retardation layer and the second retardation layer may be formed by a method of stretching or shrinking a polymer film. .) and polymerized in an oriented state.

The first retardation layer and the second retardation layer are formed by applying a composition containing a polymerizable liquid crystal compound (hereinafter also referred to as a "composition for forming a retardation layer") onto a transparent substrate. However, it is preferable to convert the polymerizable liquid crystal compound into a polymer in an oriented state by heating and cooling treatment from the viewpoint of thinning and arbitrarily designing wavelength dispersion characteristics. Moreover, as described later, the composition for forming a retardation layer may further contain a solvent, a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, a leveling agent, an adhesion improver, and the like.

The first retardation layer is preferably a liquid crystal cured film in which the polymerizable liquid crystal compound is oriented horizontally with respect to the substrate surface, and the second retardation layer is a polymerizable liquid crystal compound as the substrate. It is preferably a cured liquid crystal film cured in a state of being oriented in a direction perpendicular to the plane.

In the first retardation layer, Re1 (550), which is an in-plane retardation value for light with a wavelength of 550 nm, preferably satisfies the optical characteristics represented by the following formula (7). In addition, the first retardation layer has an in-plane retardation value Re1 (450) for light with a wavelength of 450 nm, an in-plane retardation value for light with a wavelength of 550 nm Re1 (550) and a surface for light with a wavelength of 650 nm It is also preferable that Re1 (650), which is the inner retardation value, satisfies the optical characteristics expressed by Equations (3) and (4). More preferably, the first retardation layer satisfies the optical properties represented by the following formulas (7), (3) and (4) below.
120 nm≦Re1(550)≦170 nm (7)
(In the formula, Re1 (550) represents the in-plane retardation value (in-plane retardation) of the first retardation layer for light with a wavelength of 550 nm.)
Re1(450)/Re1(550)≤1.0 (3)
1.00≦Re1(650)/Re1(550) (4)
(In the formula, Re1 (450) is the in-plane retardation value of the first retardation layer for light with a wavelength of 450 nm, and Re1 (550) is the in-plane retardation value for light with a wavelength of 550 nm of the first retardation layer. , and Re1 (650) represents the in-plane retardation value of the first retardation layer for light with a wavelength of 650 nm.)
If the in-plane retardation value Re1 (550) of the first retardation layer exceeds the range of formula (7), a problem that the front hue becomes red or blue may occur. A more preferable range of the in-plane retardation value is 130 nm≦Re1(550)≦160 nm. When "Re1(450)/Re1(550)" of the first retardation layer exceeds 1.0, the elliptically polarizing plate provided with the retardation layer increases light leakage on the short wavelength side. It is preferably 0.75 or more and 0.92 or less, more preferably 0.77 or more and 0.87 or less, and still more preferably 0.79 or more and 0.85 or less.

The in-plane retardation value of the first retardation layer can be adjusted by the thickness of the retardation layer. Since the in-plane retardation value is determined by the following formula (A), the desired in-plane retardation value (Re1 (λ): the in-plane retardation value of the first retardation layer at the wavelength λ (nm)) can be obtained by adjusting the three-dimensional refractive index and the film thickness d1. The thickness of the retardation layer is preferably 0.5 μm to 5 μm, more preferably 1 μm to 3 μm. The thickness of the retardation layer can be measured with an interference film thickness meter, a laser microscope, or a stylus film thickness meter. Incidentally, the three-dimensional refractive index depends on the molecular structure and alignment state of the polymerizable liquid crystal compound, which will be described later.
Re1(λ)=(nx1(λ)−ny1(λ))×d1 (A)
(Wherein, the refractive index ellipsoid formed by the first retardation layer has a relationship of nx1 (λ)>ny1 (λ) ≈ nz1 (λ), and nx1 (λ) is light of wavelength λ (nm) ny1(λ) is the principal refractive index in the direction parallel to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the first retardation layer, parallel to the film plane and represents the refractive index in the direction orthogonal to the direction of nx1(λ).d1 represents the thickness of the first retardation layer.)

The second retardation layer preferably has Rth2(λ), which is a retardation value in the thickness direction with respect to light having a wavelength of λnm, satisfying optical characteristics represented by the following formula (8). It is also preferred that the optical properties expressed by the following formulas (5) and (6) are satisfied. More preferably, the second retardation layer satisfies the optical properties represented by the following formulas (8), (5) and (6) below.
−100 nm≦Rth2(550)≦−50 nm (8)
(In the formula, Rth2(550) represents the retardation value in the thickness direction for light with a wavelength of 550 nm.)
Rth2(450)/Rth2(550)≤1.0 (5)
1.00≦Rth2(650)/Rth2(550) (6)
(In the formula, Rth2 (450) is the retardation value in the thickness direction for light with a wavelength of 450 nm, Rth2 (550) has the same meaning as above, and Rth2 (650) is the retardation value in the thickness direction for light with a wavelength of 650 nm. represent each.)
If the retardation value Rth2 (550) in the thickness direction of the second retardation layer exceeds the range of formula (8), the oblique hue may become red or blue. A more preferable range of the retardation value in the thickness direction is −95 nm≦Rth2(550)≦−55 nm, and a more preferable range is −90 nm≦Rth2(550)≦−60 nm. When "Rth2(450)/Rth2(550)" of the second retardation layer exceeds 1.0, the elliptically polarizing plate provided with the retardation layer increases light leakage on the short wavelength side. It is preferably 0.75 or more and 0.92 or less, more preferably 0.77 or more and 0.87 or less, and still more preferably 0.79 or more and 0.85 or less.

The retardation value in the thickness direction of the second retardation layer can be adjusted by the thickness of the retardation layer. Since the retardation value in the thickness direction is determined by the following formula (B), the desired retardation value in the thickness direction (Rth2 (λ): the position in the thickness direction of the second retardation layer at the wavelength λ (nm) retardation value) can be obtained by adjusting the three-dimensional refractive index and the film thickness d2. The thickness of the retardation layer is preferably 0.2 μm to 5 μm, more preferably 0.5 μm to 2 μm. The thickness of the retardation layer can be measured with an interference film thickness meter, a laser microscope, or a stylus film thickness meter. The three-dimensional refractive index depends on the molecular structure and orientation of the polymerizable liquid crystal compound, which will be described later.
Rth2(λ)=[(nx2(λ)+ny2(λ))/2−nz2(λ)]×d2(B)
(wherein the refractive index ellipsoid formed by the second retardation layer has a relationship of nz2(λ)>nx2(λ)≈ny2(λ), where nz2(λ) is the second position In the refractive index ellipsoid formed by the retardation layer, represents the refractive index in the direction perpendicular to the film plane for light with a wavelength λ (nm).nx2 (λ) is the refractive index ellipse formed by the second retardation layer In the body, represents the maximum refractive index in the direction parallel to the film plane for light of wavelength λ (nm), and ny2 (λ) is the refractive index ellipsoid formed by the second retardation layer in the film plane. is parallel to the direction of nx2 and perpendicular to the direction of nx2, provided that nx2(λ)=ny2(λ), nx2 (λ) represents the refractive index in any direction parallel to the film plane, where d2 represents the thickness of the second retardation layer.)

The optical film of the present invention has a first retardation layer and a second retardation layer, and satisfies the following formulas (1) and (2).
0.40≦Nz(450)≦0.60 (1)
0.40≦Nz(550)≦0.60 (2)
(Wherein, Nz (λ) is the Nz coefficient indicating the relationship of the three-dimensional refractive index for light of wavelength λ (nm), Nz (λ) = (nx (λ) - nz (λ)) / (nx ( λ)-ny(λ)) nx(λ) represents the principal refractive index in the direction parallel to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the optical film ny(λ) is the direction parallel to the film plane for light of wavelength λ (nm) and perpendicular to the direction of nx(λ) in the refractive index ellipsoid formed by the optical film. nz(λ) represents the refractive index in the refractive index ellipsoid formed by the optical film in the direction perpendicular to the plane of the film for light of wavelength λ (nm).
That is, the optical film of the present invention has a three-dimensional refractive index relationship of nx(λ)>nz(λ)>ny(λ), and the optical film has the relationships of formulas (1) and (2). , it is possible to provide excellent display characteristics of hue when mounted on a display. More preferably, Nz(λ) satisfies 0.45≦Nz(450)≦0.55 and 0.45≦Nz(550)≦0.55. Here, Nz(450) indicates the Nz coefficient at wavelength λ=450 nm, and Nz(550) indicates the Nz coefficient at wavelength λ=550 nm.

An Nz coefficient (Nz coefficient: Nz(λ)) indicating the relationship among nx(λ), ny(λ), and nz(λ) at each wavelength λ (nm) of the optical film is calculated by the following formula.
Nz(λ)=(nx(λ)−nz(λ))/(nx(λ)−ny(λ))
Further, when calculating the Nz coefficient of the optical film, if the front retardation value and the thickness direction retardation value of the first retardation layer and the second retardation layer are known, the following formula (C ) can also be calculated.
Nz(λ)=(Rth1(λ)+Rth2(λ))/(Re1(λ)+Re2(λ))+0.5 (C)
(Wherein, Re1(λ) is the front retardation value of the first retardation layer at the wavelength λ (nm), Re2(λ) is the front retardation value of the second retardation layer at the wavelength λ (nm) Rth1 (λ) is the retardation value in the thickness direction of the first retardation layer at the wavelength λ (nm), and Rth2 (λ) is the retardation value of the second retardation layer at the wavelength λ (nm). It is a retardation value in the thickness direction.)

[Polymerizable liquid crystal]
A polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable functional group, particularly a photopolymerizable functional group. A photopolymerizable functional group is a group that can participate in a polymerization reaction by an active radical generated from a photopolymerization initiator, an acid, or the like. Photopolymerizable functional groups include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group and oxetanyl group. Among them, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group and an oxetanyl group are preferred, and an acryloyloxy group is more preferred. Thermotropic liquid crystals or lyotropic liquid crystals may be used as liquid crystals, but thermotropic liquid crystals are preferred because they allow precise film thickness control. The phase-ordered structure of the thermotropic liquid crystal may be nematic liquid crystal or smectic liquid crystal.

In the present invention, as the polymerizable liquid crystal compound, the structure of the following formula (I) is particularly preferable in terms of exhibiting the reverse wavelength dispersion described above.

In formula (I), Ar represents a divalent aromatic group which may have a substituent. The aromatic group referred to herein is a group having a planar cyclic structure, and the number of π electrons in the ring structure is [4n+2] according to Hückel's rule. Here, n represents an integer. In the case where a ring structure is formed by including heteroatoms such as -N= and -S-, the Hückel rule is satisfied including the non-covalently bonded electron pairs on these heteroatoms, and the case of having aromaticity is also included. At least one or more of a nitrogen atom, an oxygen atom and a sulfur atom are preferably contained in the divalent aromatic group.
G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atom contained in the divalent aromatic group or divalent alicyclic hydrocarbon group is a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, a carbon may be substituted with an alkoxy group, cyano group or nitro group having a number of 1 to 4, and the carbon atoms constituting the divalent aromatic group or divalent alicyclic hydrocarbon group are an oxygen atom or a sulfur atom; Alternatively, it may be substituted with a nitrogen atom.
L ¹ , L ² _, B ¹ and B ² are each independently a single bond or a divalent linking group.
k and l each independently represents an integer of 0 to 3 and satisfies the relationship 1≦k+l. Here, when 2≦k+l, B ¹ and B ² and G ¹ and G ² may be the same or different from each other.
E ¹ and E ² each independently represent an alkanediyl group having 1 to 17 carbon atoms, wherein the hydrogen atoms contained in the alkanediyl group may be substituted with a halogen atom, and the alkanediyl group —CH ₂ — included may be substituted with —O—, —S—, or —Si—. P ¹ and P ² independently represent a polymerizable group or a hydrogen atom, at least one of which is a polymerizable group.

G ¹ and G ² are each independently preferably a 1,4-phenylenediyl group optionally substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms. , a 1,4-cyclohexanediyl group optionally substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably 1 substituted with a methyl group ,4-phenylenediyl group, unsubstituted 1,4-phenylenediyl group or unsubstituted 1,4-trans-cyclohexanediyl group, particularly preferably unsubstituted 1,4-phenylenediyl group or unsubstituted It is a substituted 1,4-trans-cyclohexanediyl group.
At least one of G ¹ and G ² present in plurality is preferably a divalent alicyclic hydrocarbon group, and at least one of G ¹ and G ² bonded to L ¹ or L ² is more preferably a divalent alicyclic hydrocarbon group.

L ¹ and L ² are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, —O—, —S—, —R ^a1 OR ^a2 —, —R ^a3 COOR ^a4 —, —R ^a5 OCOR ^a6 -, R ^a7 OC=OOR ^a8 -, -N=N-, -CR ^c =CR ^d -, or -C≡C-. Here, R ^a1 to R ^a8 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms, and R ^c and R ^d represent an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L ¹ and L ² are each independently more preferably a single bond, -OR ^a2-1 -, -CH ₂ -, -CH ₂ CH ₂ -, ^{-COOR a4-1} -, or -OCOR ^a6-1 - be. Here, R ^a2-1 , R ^a4-1 and R ^a6-1 each independently represent a single bond, —CH ₂ — or —CH ₂ CH ₂ —. L ¹ and L ² are each independently more preferably a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, or -OCO-.

B ¹ and B ² are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, —O—, —S—, —R ^a9 OR ^a10 —, —R ^a11 COOR ^a12 —, —R ^a13 OCOR ^a14 -, or R ^a15 OC= ^{OOR a16} -. Here, R ^a9 to R ^a16 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms. B ¹ and B ² are each independently more preferably a single bond, -OR ^a10-1 -, -CH ₂ -, -CH ₂ CH ₂ -, ^{-COOR a12-1} -, or -OCOR ^a14-1 - be. Here, R ^a10-1 , R ^a12-1 and R ^a14-1 each independently represent a single bond, —CH ₂ — or —CH ₂ CH ₂ —. B ¹ and B ² are each independently more preferably a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH _{2 CH 2 -, -OCO- or -OCOCH 2 CH 2 - ,} is.

k and l are preferably in the range of 2≦k+l≦6, preferably k+l=4, more preferably k=2 and l=2, from the viewpoint of exhibiting reverse wavelength dispersion. It is more preferable that k=2 and l=2 because the structure is symmetrical.

E ¹ and E ² are each independently preferably an alkanediyl group having 1 to 17 carbon atoms, more preferably an alkanediyl group having 4 to 12 carbon atoms.

Polymerizable groups represented by P ¹ or P ² include epoxy group, vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group and oxiranyl group. , and oxetanyl groups. Among them, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group and an oxetanyl group are preferred, and an acryloyloxy group is more preferred.

Ar preferably has at least one selected from an optionally substituted aromatic hydrocarbon ring, an optionally substituted aromatic heterocyclic ring, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include benzene ring, naphthalene ring, anthracene ring and the like, with benzene ring and naphthalene ring being preferred. Examples of the aromatic heterocyclic ring include furan ring, benzofuran ring, pyrrole ring, indole ring, thiophene ring, benzothiophene ring, pyridine ring, pyrazine ring, pyrimidine ring, triazole ring, triazine ring, pyrroline ring, imidazole ring, and pyrazole ring. , thiazole ring, benzothiazole ring, thienothiazole ring, oxazole ring, benzoxazole ring, and phenanthroline ring. Among them, it preferably has a thiazole ring, a benzothiazole ring, or a benzofuran ring, and more preferably has a benzothiazole group. Moreover, when a nitrogen atom is contained in Ar, the nitrogen atom preferably has a π electron.

In formula (I), the total number Nπ of _π electrons contained in the divalent aromatic group represented by Ar is preferably 8 or more, more preferably 10 or more, still more preferably 14 or more, especially It is preferably 16 or more. Also, it is preferably 30 or less, more preferably 26 or less, and still more preferably 24 or less.

Examples of aromatic groups represented by Ar include the following groups.

In formulas (Ar-1) to (Ar-22), * represents a linking moiety, and Z ⁰ , Z ¹ and Z ² each independently represent a hydrogen atom, a halogen atom, or an alkyl having 1 to 12 carbon atoms. a cyano group, a nitro group, an alkylsulfinyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, a carboxyl group, a fluoroalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, alkylthio group having 1 to 12 carbon atoms, N-alkylamino group having 1 to 12 carbon atoms, N,N-dialkylamino group having 2 to 12 carbon atoms, N-alkylsulfamoyl group having 1 to 12 carbon atoms or carbon represents an N,N-dialkylsulfamoyl group of numbers 2 to 12;

Q ¹ , Q ² and Q ³ each independently represent -CR ^2' R ^3' -, -S-, -NH-, -NR ^2' -, -CO- or -O-, and R ^2' and R ^3′ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

J ¹ and J ² each independently represent a carbon atom or a nitrogen atom.

Y ¹ , Y ² and Y ³ each independently represent an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group.

W ¹ and W ² each independently represent a hydrogen atom, a cyano group, a methyl group or a halogen atom, and m represents an integer of 0-6.

Examples of the aromatic hydrocarbon group for Y ¹ , Y ² and Y ³ include aromatic hydrocarbon groups having 6 to 20 carbon atoms such as phenyl group, naphthyl group, anthryl group, phenanthryl group and biphenyl group. , is preferably a naphthyl group, more preferably a phenyl group. The aromatic heterocyclic group includes a C4-20 group containing at least one heteroatom such as a nitrogen atom, an oxygen atom, a sulfur atom such as a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group and a benzothiazolyl group. An aromatic heterocyclic group can be mentioned, and a furyl group, a thienyl group, a pyridinyl group, a thiazolyl group, and a benzothiazolyl group are preferable.

Y ¹ , Y ² and Y ³ may each independently be an optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group. A polycyclic aromatic hydrocarbon group refers to a condensed polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring assembly. A polycyclic aromatic heterocyclic group refers to a condensed polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

Z ⁰ , Z ¹ and Z ² are each independently preferably a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkoxy group having 1 to 12 carbon atoms, and Z ⁰ is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a cyano group, and Z ¹ and Z ² are more preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, or a cyano group.

Q ¹ , Q ² and Q ³ are preferably -NH-, -S-, -NR ^2' - and -O-, and R ^2' is preferably a hydrogen atom. Among them, -S-, -O- and -NH- are particularly preferred.

Among formulas (Ar-1) to (Ar-22), formulas (Ar-6) and (Ar-7) are preferable from the viewpoint of molecular stability.
In formulas (Ar-16) to (Ar-22), Y ¹ may form an aromatic heterocyclic group together with the nitrogen atom to which it is attached and Z ⁰ . Examples of the aromatic heterocyclic group include those described above as the aromatic heterocyclic ring that Ar may have, and examples thereof include pyrrole ring, imidazole ring, pyrroline ring, pyridine ring, pyrazine ring, pyrimidine ring, indole ring, quinoline ring, isoquinoline ring, purine ring, pyrrolidine ring and the like. This aromatic heterocyclic group may have a substituent. In addition, Y ¹ , together with the nitrogen atom and Z ⁰ to which it is attached, may be the aforementioned optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group. Examples include benzofuran ring, benzothiazole ring, benzoxazole ring and the like.

The total content of the polymerizable liquid crystal compound in 100 parts by mass of the solid content of the retardation layer-forming composition is usually 70 parts by mass to 99.5 parts by mass, preferably 80 parts by mass to 99 parts by mass. parts, more preferably 80 to 94 parts by mass, still more preferably 80 to 90 parts by mass. If the total content is within the above range, the orientation of the obtained retardation layer tends to be high. Here, the solid content refers to the total amount of components of the composition excluding the solvent.

[solvent]
As the solvent, a solvent capable of dissolving the polymerizable liquid crystal compound is preferable, and a solvent inert to the polymerization reaction of the polymerizable liquid crystal compound is preferable.
Examples of solvents include alcohol solvents such as water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether and propylene glycol monomethyl ether; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate; , gamma-butyrolactone, propylene glycol methyl ether acetate and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone and methyl isobutyl ketone; aliphatic carbonization such as pentane, hexane and heptane. Hydrogen solvents; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; Amide solvents such as 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like are included. These solvents may be used alone or in combination of two or more. Among them, alcohol solvents, ester solvents, ketone solvents, chlorine-containing solvents, amide solvents and aromatic hydrocarbon solvents are preferred.

The content of the solvent in 100 parts by weight of the composition is preferably 50 parts by weight to 98 parts by weight, more preferably 70 parts by weight to 95 parts by weight. Therefore, the solid content in 100 parts by mass of the composition is preferably 2 to 50 parts by mass. When the solid content of the composition is 50 parts by mass or less, the viscosity of the composition is low, so that the thickness of the retardation layer becomes substantially uniform, and unevenness tends to be less likely to occur in the retardation layer. The solid content can be appropriately determined in consideration of the thickness of the retardation layer to be produced.

<Polymerization initiator>
A polymerization initiator is a compound capable of generating a reactive species with the contribution of heat or light and initiating a polymerization reaction of a polymerizable liquid crystal or the like. Reactive species include active species such as radicals or cations or anions. Among them, a photopolymerization initiator that generates radicals by light irradiation is preferable from the viewpoint that reaction control is easy.
Examples of photopolymerization initiators include benzoin compounds, benzophenone compounds, benzylketal compounds, α-hydroxyketone compounds, α-aminoketone compounds, triazine compounds, iodonium salts and sulfonium salts. Specifically, Irgacure (registered trademark) 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369, Irgacure 379, Irgacure 127, Irgacure 2959, Irgacure 754, Irgacure 379EG (above, BASF Japan Corporation ), Seikuol BZ, Seikuol Z, Seikuol BEE (manufactured by Seiko Chemical Co., Ltd.), Kayacure BP100 (manufactured by Nippon Kayaku Co., Ltd.), Kayacure UVI-6992 (manufactured by Dow), Adeka Optomer SP- 152, Adeka Optomer SP-170, Adeka Optomer N-1717, Adeka Optomer N-1919, Adeka Arkles NCI-831, Adeka Arkles NCI-930 (manufactured by ADEKA Co., Ltd.), TAZ-A, TAZ -PP (manufactured by Nihon SiberHegner Co., Ltd.) and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.).
The composition for forming a retardation layer contains at least one type of photopolymerization initiator, preferably one type or two types.

Since the photopolymerization initiator can fully utilize the energy emitted from the light source and is excellent in productivity, it is preferable that the maximum absorption wavelength is 300 nm to 400 nm, more preferably 300 nm to 380 nm. Polymerization initiators and oxime photopolymerization initiators are preferred.

α-Acetophenone compounds include 2-methyl-2-morpholino-1-(4-methylsulfanylphenyl)propan-1-one, 2-dimethylamino-1-(4-morpholinophenyl)-2-benzylbutane-1 -one and 2-dimethylamino-1-(4-morpholinophenyl)-2-(4-methylphenylmethyl)butan-1-one and the like, more preferably 2-methyl-2-morpholino-1-( 4-methylsulfanylphenyl)propan-1-one and 2-dimethylamino-1-(4-morpholinophenyl)-2-benzylbutan-1-one. Commercially available α-acetophenone compounds include Irgacure 369, 379EG and 907 (manufactured by BASF Japan Ltd.) and Seikuol BEE (manufactured by Seiko Kagaku Co., Ltd.).

The oxime-based photopolymerization initiator generates methyl radicals upon irradiation with light. Polymerization of the polymerizable liquid crystal compound in the deep portion of the retardation layer favorably proceeds due to the methyl radicals. Moreover, from the viewpoint of more efficiently progressing the polymerization reaction in the deep part of the retardation layer, it is preferable to use a photopolymerization initiator capable of efficiently utilizing ultraviolet rays having a wavelength of 350 nm or more. Triazine compounds and oxime ester-type carbazole compounds are preferable as photopolymerization initiators capable of efficiently utilizing ultraviolet rays having a wavelength of 350 nm or more, and oxime ester-type carbazole compounds are more preferable from the viewpoint of sensitivity. Oxime ester-type carbazole compounds include 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl )-9H-carbazol-3-yl]-1-(O-acetyloxime) and the like. Commercially available oxime ester-type carbazole compounds include Irgacure OXE-01, Irgacure OXE-02, Irgacure OXE-03 (manufactured by BASF Japan Ltd.), Adeka Optomer N-1919, and Adeka Arkles NCI-831 (manufactured by BASF Japan Ltd.). , manufactured by ADEKA Corporation) and the like.

The amount of the photopolymerization initiator added is usually 0.1 parts by mass to 30 parts by mass, preferably 1 part by mass to 20 parts by mass, more preferably 1 part by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. Parts by mass to 15 parts by mass. Within the above range, the reaction of the polymerizable group proceeds sufficiently and the orientation of the polymerizable liquid crystal compound is less likely to be disturbed.

By adding a polymerization inhibitor, the polymerization reaction of the polymerizable liquid crystal compound can be controlled. Examples of polymerization inhibitors include hydroquinones having substituents such as hydroquinone and alkyl ethers; catechols having substituents such as alkyl ethers such as butyl catechol; pyrogallols, 2,2,6,6-tetramethyl-1- Radical scavengers such as piperidinyloxy radicals; thiophenols; β-naphthylamines and β-naphthols. In order to polymerize the polymerizable liquid crystal compound without disturbing the orientation of the polymerizable liquid crystal compound, the content of the polymerization inhibitor is usually 0.01 to 10 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. Yes, preferably 0.1 to 5 parts by mass, more preferably 0.1 to 3 parts by mass.

Furthermore, by using a sensitizer, the sensitivity of the photopolymerization initiator can be increased. Examples of photosensitizers include xanthones such as xanthone and thioxanthone; anthracenes having substituents such as anthracene and alkyl ether; phenothiazine; and rubrene. Examples of photosensitizers include xanthones such as xanthone and thioxanthone; anthracenes having substituents such as anthracene and alkyl ether; phenothiazine; and rubrene. The content of the photosensitizer is usually 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. 3 parts by mass.

[Leveling agent]
The leveling agent is an additive that has the function of adjusting the fluidity of the composition and making the film obtained by coating the composition more flat. and perfluoroalkyl-based leveling agents. Specifically, DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (all manufactured by Dow Corning Toray Co., Ltd.), KP321, KP323, KP324, KP326, KP340, KP341, X22-161A, KF6001, KBM-1003, KBE-1003, KBM-303, KBM-402, KBM-403, KBE-402, KBE-403, KBM-1403, KBM-502, KBM-503, KBE- 502, KBE-503, KBM-5103, KBM-602, KBM-603, KBM-903, KBE-903, KBE-9103, KBM-573, KBM-575, KBE-585, KBM-802, KBM-802, KBM-803, KBE-846, KBE-9007 (all manufactured by Shin-Etsu Chemical Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, TSF4460 (all Momentive Performance Materials Japan LLC), Fluorinert (registered trademark) FC-72, FC-40, FC-43, FC-3283 (all manufactured by Sumitomo 3M Co., Ltd.), Megafac (registered trademark) ) R-08, R-30, R-90, F-410, F-411, F-443, F-445, F-470, F-477, F-479, F-482, F-483 (all manufactured by DIC Corporation), F-top (trade name) EF301, EF303, EF351, EF352 (all manufactured by Mitsubishi Materials Electronic Chemical Co., Ltd.) , Surflon (registered trademark) S-381, S-382, S-383, S-393, SC-101, SC-105, KH-40, SA-100 (above, all AGC Seimi Chemical ( Co., Ltd.), trade names E1830, E5844 (manufactured by Daikin Fine Chemicals Laboratory Co., Ltd.), BM-1000, BM-1100, BYK-352, BYK-353 and BYK-361N (all trade names: BM Chemie) made) and the like.

The content of the leveling agent in the retardation layer-forming composition is preferably 0.01 parts by mass to 5 parts by mass, more preferably 0.05 parts by mass to 3 parts by mass, with respect to 100 parts by mass of the polymerizable liquid crystal compound. . When the content of the leveling agent is within the above range, the polymerizable liquid crystal compound can be easily horizontally aligned, and the resulting retardation layer tends to be smoother, which is preferable. The composition for forming a retardation layer may contain two or more leveling agents.

[Base material]
Examples of the base material include glass base materials and film base materials. Film base materials are preferable from the viewpoint of workability, and long roll-shaped films are more preferable in terms of continuous production. Examples of resins constituting the film substrate include polyolefins such as polyethylene, polypropylene, and norbornene-based polymers; cyclic olefin-based resins; polyvinyl alcohol; polyethylene terephthalate; and cellulose esters such as cellulose acetate propionate; polyethylene naphthalate; polycarbonates; polysulfones; polyethersulfones; polyetherketones;
Commercially available cellulose ester substrates include "Fujitac Film" (manufactured by Fuji Photo Film Co., Ltd.);
Commercially available cyclic olefin resins include "Topas" (registered trademark) (manufactured by Ticona (Germany)), "Arton" (registered trademark) (manufactured by JSR Corporation), "ZEONOR" (registered trademark), "ZEONEX" (registered trademark) (manufactured by Nippon Zeon Co., Ltd.) and "APEL" (registered trademark) (manufactured by Mitsui Chemicals, Inc.). Such a cyclic olefin resin can be used as a substrate by forming a film by a known method such as a solvent casting method or a melt extrusion method. A commercially available cyclic olefin resin base material can also be used. Examples of commercially available cyclic olefin resin substrates include "Escina" (registered trademark), "SCA40" (registered trademark) (manufactured by Sekisui Chemical Co., Ltd.), and "Zeonor Film" (registered trademark) (manufactured by Optes Co., Ltd.). ) and “Arton Film” (registered trademark) (manufactured by JSR Corporation).
As for the thickness of the base material, it is preferable that the base material is as thin as possible in terms of mass that can be handled practically. The thickness of the substrate is usually 5 μm to 300 μm, preferably 20 μm to 200 μm. Further, by peeling off the base material and transferring only the polymer in the aligned state of the polymerizable liquid crystal compound, a further thinning effect can be obtained.

[Alignment film]
An orientation film is preferably formed on the surface of the substrate on which the composition for forming a retardation layer is applied. The alignment film has an alignment control force for aligning the polymerizable liquid crystal compound in a desired direction.

The alignment film has solvent resistance that does not dissolve when the retardation layer-forming composition is applied, etc., and also has heat resistance in heat treatment for removing the solvent and for aligning the polymerizable liquid crystal compound described later. preferable.

Such an alignment film facilitates the alignment of the polymerizable liquid crystal compound. Further, various alignments such as vertical alignment, horizontal alignment, hybrid alignment, and tilted alignment can be controlled depending on the type of alignment film, rubbing conditions, and light irradiation conditions.

As the alignment film forming the first retardation layer, an alignment film exhibiting alignment control force in the horizontal direction is applied. Examples of such a horizontal alignment film include a rubbing alignment film, a photo-alignment film, and a groove alignment film having an uneven pattern or a plurality of grooves on the surface. When applied to a long roll-shaped film, a photo-alignment film is preferable because the alignment direction can be easily controlled.

An oriented polymer can be used for the rubbed oriented film. Examples of oriented polymers include polyamides and gelatins having amide bonds, polyimides having imide bonds and their hydrolysates such as polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxazole, polyethyleneimine, and polystyrene. , polyvinylpyrrolidone, polyacrylic acid and polyacrylates. You may combine two or more types of oriented polymers.

A rubbing alignment film is generally produced by coating a substrate with a composition in which an alignment polymer is dissolved in a solvent (hereinafter also referred to as an alignment polymer composition), removing the solvent to form a coating film, and removing the coating film. Orientation regulating force can be imparted by rubbing.

The concentration of the oriented polymer in the oriented polymer composition may be within a range in which the oriented polymer is completely dissolved in the solvent. The content of the oriented polymer in the oriented polymer composition is preferably 0.1 to 20% by mass, more preferably 0.1 to 10% by mass.

Orientable polymer compositions are commercially available. Commercially available oriented polymer compositions include Sunever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.) and Optomer (registered trademark, manufactured by JSR Corporation).

Examples of the method of applying the oriented polymer composition to the substrate include the same methods as the method of applying the later-described composition for forming a retardation layer to the substrate. Methods for removing the solvent contained in the oriented polymer composition include natural drying, ventilation drying, heat drying, and vacuum drying.

Examples of the rubbing method include a method in which the coating film is brought into contact with a rubbing roll wound with a rubbing cloth and rotating. A plurality of regions (patterns) with different alignment directions can be formed in the alignment film by masking during the rubbing process.

A photo-alignment film is usually formed by applying a composition for forming a photo-alignment film containing a polymer or monomer having a photoreactive group and a solvent to a substrate, and irradiating polarized light (preferably polarized UV) after removing the solvent. obtained by The photo-alignment film can arbitrarily control the direction of the alignment regulating force by selecting the polarization direction of the polarized light to be irradiated.

A photoreactive group refers to a group that produces alignment ability upon irradiation with light. Specific examples thereof include groups involved in photoreactions that are the origin of alignment ability, such as orientation-inducing reactions, isomerization reactions, photodimerization reactions, photocrosslinking reactions, and photodegradation reactions of molecules caused by light irradiation. The photoreactive group is preferably a group having an unsaturated bond, particularly a double bond, such as carbon-carbon double bond (C=C bond), carbon-nitrogen double bond (C=N bond), nitrogen-nitrogen Groups having at least one selected from the group consisting of a double bond (N=N bond) and a carbon-oxygen double bond (C=O bond) are particularly preferred.

Photoreactive groups having a C═C bond include, for example, vinyl groups, polyene groups, stilbene groups, stilbazole groups, stilbazolium groups, chalcone groups and cinnamoyl groups. Examples of the photoreactive group having a C═N bond include groups having structures such as aromatic Schiff bases and aromatic hydrazones. The photoreactive group having an N=N bond includes, for example, an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a bisazo group, a formazan group, and a group having an azoxybenzene structure. Photoreactive groups having a C=O bond include, for example, benzophenone groups, coumarin groups, anthraquinone groups and maleimide groups. These groups may have substituents such as alkyl groups, alkoxy groups, aryl groups, allyloxy groups, cyano groups, alkoxycarbonyl groups, hydroxyl groups, sulfonic acid groups, and halogenated alkyl groups.

A group involved in a photodimerization reaction or a photocrosslinking reaction is preferable from the viewpoint of excellent orientation. Among them, a photoreactive group that participates in a photodimerization reaction is preferable, and a cinnamoyl group is preferred because the amount of polarized light irradiation required for alignment is relatively small, and a photoalignment film having excellent thermal stability and stability over time can be easily obtained. and chalcone groups are preferred. As a polymer having a photoreactive group, a polymer having a cinnamoyl group having a cinnamic acid structure or a cinnamic acid ester structure at the end of the polymer side chain is particularly preferred.

The content of the polymer or monomer having a photoreactive group in the composition for forming a photo-alignment film can be adjusted depending on the type of polymer or monomer and the thickness of the desired photo-alignment film, and is at least 0.2% by mass or more. preferably in the range of 0.3 to 10% by mass.

Examples of the method for applying the composition for forming a photo-alignment film onto the substrate include the same methods as the method for applying the composition for forming a retardation layer, which will be described later, onto the substrate. The method for removing the solvent from the coated composition for forming a photo-alignment film includes the same method as the method for removing the solvent from the orienting polymer composition.

In order to irradiate polarized light, the composition for forming a photo-alignment film coated on the substrate may be directly irradiated with polarized light after the solvent has been removed. It may be of a form in which the light is transmitted through the material and irradiated. Also, the polarized light is preferably substantially parallel light. The wavelength of the polarized light to be irradiated is preferably in a wavelength range in which the photoreactive group of the polymer or monomer having a photoreactive group can absorb the light energy. Specifically, UV (ultraviolet rays) with a wavelength in the range of 250 nm to 400 nm is particularly preferred. Examples of the light source for irradiating the polarized light include a xenon lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, and an ultraviolet light laser such as KrF or ArF. Among them, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, and a metal halide lamp are preferable because of their high emission intensity of ultraviolet rays having a wavelength of 313 nm. Polarized UV can be emitted by passing the light from the light source through a suitable polarizing element. Polarizing elements include polarizing filters, polarizing prisms such as Glan-Thompson and Glan-Taylor, and wire grids. Among them, a wire grid type polarizing element is preferable from the viewpoint of large area and resistance to heat.

A plurality of regions (patterns) having different liquid crystal orientation directions can be formed by masking during rubbing or polarized light irradiation.

A groove alignment film is a film having an uneven pattern or a plurality of grooves on its surface. When a polymerizable liquid crystal compound is applied to a film having a plurality of linear grooves arranged at regular intervals, liquid crystal molecules are aligned along the grooves.
As a method for obtaining a grooved alignment film, after exposure through an exposure mask having pattern-shaped slits on the surface of a photosensitive polyimide film, development and rinsing are performed to form an uneven pattern, and a plate having grooves on the surface. A method of forming a UV curable resin layer before curing on a shaped master, transferring the resin layer to a substrate and then curing it, and a method of forming a UV curable resin film before curing formed on the substrate with a plurality of A method of pressing a roll-shaped master plate having grooves to form irregularities and then curing the same can be used.

The thickness of the alignment film for forming the first retardation layer is usually in the range of 10-10000 nm, preferably in the range of 10-1000 nm, more preferably in the range of 50-500 nm.

As the alignment film forming the second retardation layer, an alignment film having alignment control force in the vertical direction (hereinafter also referred to as a vertical alignment film) is applied. As the vertical alignment film, it is preferable to apply a material that lowers the surface tension of the substrate surface. Examples of such materials include the above-described oriented polymers, fluorine-based polymers such as perfluoroalkyl, polyimide compounds, silane compounds, and polysiloxane compounds obtained by condensation reaction thereof. Silane compounds are preferred because they tend to reduce the surface tension.

As the silane compound, silicone-based compounds such as the silane coupling agent described above can be suitably applied. aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, Cydoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercapto propyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, 3-glycidoxypropylethoxydimethylsilane and the like. Two or more silane compounds may be used.

The silane compound may be of the silicone monomer type or of the silicone oligomer (polymer) type. Examples of silicone oligomers in the form of (monomer)-(monomer) copolymers include the following.

3-mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-mercaptopropyltriethoxysilane-tetramethoxysilane copolymer, and 3-mercaptopropyltriethoxysilane-tetraethoxy Mercaptopropyl group-containing copolymers, such as silane copolymers;

mercaptomethyl groups, such as mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer, mercaptomethyltrimethoxysilane-tetraethoxysilane copolymer, mercaptomethyltriethoxysilane-tetramethoxysilane copolymer, and mercaptomethyltriethoxysilane-tetraethoxysilane copolymer; containing copolymer;

3-methacryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltriethoxysilane - tetraethoxysilane copolymer, 3-methacryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, and Copolymers containing methacryloyloxypropyl groups, such as 3-methacryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymer;

3-acryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltriethoxysilane -tetraethoxysilane copolymer, 3-acryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, and copolymers containing acryloyloxypropyl groups, such as 3-acryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymer;

vinyltrimethoxysilane-tetramethoxysilane copolymer, vinyltrimethoxysilane-tetraethoxysilane copolymer, vinyltriethoxysilane-tetramethoxysilane copolymer, vinyltriethoxysilane-tetraethoxysilane copolymer, vinylmethyldimethoxysilane-tetramethoxysilane copolymer, vinyl group-containing copolymers such as vinylmethyldimethoxysilane-tetraethoxysilane copolymer, vinylmethyldiethoxysilane-tetramethoxysilane copolymer, and vinylmethyldiethoxysilane-tetraethoxysilane copolymer;

3-aminopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetraethoxysilane Copolymers, 3-aminopropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-aminopropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-aminopropylmethyldiethoxysilane-tetramethoxysilane copolymer, and 3-aminopropylmethyldiethoxy Amino group-containing copolymers, such as silane-tetraethoxysilane copolymers, and the like.

Among them, a silane compound having an alkyl group at the molecular terminal is preferable, and a silane compound having an alkyl group having 6 to 20 carbon atoms is more preferable. Since these silane compounds are liquid in many cases, they may be applied to the substrate as they are or may be dissolved in a solvent and applied to the substrate. In addition, it may be dissolved in a solvent and applied to the base material together with various polymers as a binder.

Examples of the method of applying the vertical alignment film to the substrate include the same method as the method of applying the composition for forming a retardation layer, which will be described later, to the substrate. The method for removing the solvent from the coated composition for forming a photo-alignment film includes the same method as the method for removing the solvent from the orienting polymer composition.

The thickness of the alignment film for forming the second retardation layer is usually in the range of 10-10000 nm, preferably in the range of 50-5000 nm, more preferably in the range of 100-500 nm.

<<Method for producing retardation layer>>
<Application of composition for forming retardation layer>
A retardation layer can be formed by applying the composition for forming a retardation layer onto the substrate or the alignment film. Examples of the method for applying the retardation layer-forming composition onto the substrate include extrusion coating, direct gravure coating, reverse gravure coating, CAP coating, slit coating, micro gravure, die coating, and inkjet method. etc. Moreover, the method of apply|coating using coaters, such as a dip coater, a bar coater, a spin coater, etc. are mentioned. Among them, when applying continuously in a Roll to Roll format, a micro gravure method, an inkjet method, a slit coating method, or a die coating method is preferable. A spin-coating method with a high is preferred.

<Drying of retardation layer-forming composition>
Drying methods for removing the solvent contained in the retardation layer-forming composition include, for example, natural drying, ventilation drying, heat drying, reduced pressure drying, and a combination thereof. Among them, natural drying or heat drying is preferable. The drying temperature is preferably in the range of 0 to 200°C, more preferably in the range of 20 to 150°C, even more preferably in the range of 50 to 130°C. The drying time is preferably 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes. The composition for forming a photo-alignment film and the aligning polymer composition can also be dried in the same manner.

<Polymerization of polymerizable liquid crystal compound>
As a method for polymerizing the polymerizable liquid crystal compound, photopolymerization is preferable. Photopolymerization is carried out by irradiating an active energy ray to a layered product in which a retardation layer-forming composition containing a polymerizable liquid crystal compound is applied on a substrate or an alignment film. As the active energy ray to be irradiated, the type of polymerizable liquid crystal compound contained in the dry film (especially the type of photopolymerizable functional group possessed by the polymerizable liquid crystal compound), and the photopolymerization initiator when a photopolymerization initiator is included. are appropriately selected according to the types and amounts thereof. Specifically, one or more types of light selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, and γ-rays can be used. Among them, ultraviolet light is preferable in that the progress of the polymerization reaction can be easily controlled and a photopolymerization apparatus that is widely used in the art can be used. It is preferable to select the type of the polar liquid crystal compound.

Examples of the light source of the active energy ray include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium lamps, excimer lasers, and wavelength ranges. LED light sources, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, etc., which emit light in the range of 380 to 440 nm can be used.

The ultraviolet irradiation intensity is usually 10 mW/cm ² to 3,000 mW/cm ² . The ultraviolet irradiation intensity is preferably in the wavelength region effective for activating the cationic polymerization initiator or the radical polymerization initiator. The time for light irradiation is usually 0.1 seconds to 10 minutes, preferably 0.1 seconds to 5 minutes, more preferably 0.1 seconds to 3 minutes, still more preferably 0.1 seconds. ~1 minute. When irradiated once or multiple times with such an irradiation intensity of ultraviolet rays, the cumulative amount of light is 10 mJ/cm ² to 3,000 mJ/cm ² , preferably 50 mJ/cm ² to 2,000 mJ/cm ² , more preferably 100 mJ. /cm ² to 1,000 mJ/cm ² . If the integrated amount of light is less than this range, the curing of the polymerizable liquid crystal compound may be insufficient, and good transferability may not be obtained. Conversely, when the integrated amount of light is above this range, the optical film including the retardation layer may be colored.

[Polarizer]
The elliptically polarizing plate of the present invention comprises a polarizing plate and the optical film of the present invention. Thus, the elliptically polarizing plate of the present invention can be obtained.
In one embodiment of the present invention, when the polarizing plate and the optical film of the present invention are laminated, the slow axis (optical axis) of the first retardation layer and the absorption axis of the polarizing plate are substantially 45°. It is preferable to laminate such that By laminating the optical film of the present invention so that the slow axis (optical axis) of the optical film of the present invention and the absorption axis of the polarizing plate are at substantially 45°, a function as a circularly polarizing plate can be obtained. Incidentally, substantially 45° is usually in the range of 45±5°.

The polarizing plate is composed of a polarizer having a polarizing function. Examples of the polarizer include a stretched film to which a dye having anisotropic absorption is adsorbed, or a film in which a dye having anisotropic absorption is coated and oriented. Dyes having absorption anisotropy include dichroic dyes.

A stretched film having a dye having absorption anisotropy adsorbed is usually produced by a process of uniaxially stretching a polyvinyl alcohol resin film, and dyeing the polyvinyl alcohol resin film with a dichroic dye to remove the dichroic dye. It is produced through a process of adsorbing, a process of treating the polyvinyl alcohol-based resin film on which the dichroic dye is adsorbed with an aqueous boric acid solution, and a process of washing with water after the treatment with the aqueous boric acid solution. A polarizing plate is obtained by laminating the polarizer thus obtained and a transparent protective film. Dichroic dyes include iodine and dichroic organic dyes. Dichroic organic dyes include dichroic direct dyes composed of disazo compounds such as C.I. DIRECT RED 39 and dichroic direct dyes composed of compounds such as trisazo and tetrakisazo. As described above, the thickness of the polarizer obtained by subjecting the polyvinyl alcohol resin film to uniaxial stretching, dyeing with a dichroic dye, boric acid treatment, washing with water and drying is preferably 5 μm to 40 μm.

[Adhesive]
Examples of adhesives for bonding the polarizing plate and the optical film of the present invention or the optical film of the present invention and the display device include pressure-sensitive adhesives, drying-hardening adhesives, and chemically reactive adhesives. Examples of chemically reactive adhesives include active energy ray-curable adhesives. As the adhesive between the polarizing plate and the optical film of the present invention, an adhesive layer formed from a pressure-sensitive adhesive, a drying-hardening adhesive, or an active energy ray-curable adhesive is preferable. As the adhesive between the optical film and the display device, a pressure-sensitive adhesive or an active energy ray-curable adhesive is preferred.

A pressure-sensitive adhesive usually contains a polymer and may contain a solvent.
Polymers include acrylic polymers, silicone polymers, polyesters, polyurethanes, polyethers, and the like. Among them, acrylic pressure-sensitive adhesives containing acrylic polymers have excellent optical transparency, moderate wettability and cohesive strength, excellent adhesiveness, high weather resistance and heat resistance, and are resistant to heat. It is preferable because it is less likely to float or peel off under humidified conditions.

Examples of acrylic polymers include (meth)acrylates in which the alkyl group of the ester moiety is an alkyl group having 1 to 20 carbon atoms such as a methyl group, an ethyl group, or a butyl group (hereinafter, acrylates and methacrylates are collectively referred to as (meth)acrylates and acrylic acid and methacrylic acid may be collectively referred to as (meth)acrylic acid), and (meth)acrylic acid and hydroxyethyl (meth)acrylate having functional groups such as (meth) Copolymers with acrylic monomers are preferred.

The pressure-sensitive adhesive containing such a copolymer has excellent adhesiveness, and can be removed relatively easily without causing adhesive residue or the like on the display device even when it is removed after being attached to the display device. is possible. The glass transition temperature of the acrylic polymer is preferably 25°C or lower, more preferably 0°C or lower. The weight average molecular weight of such acrylic polymer is preferably 100,000 or more.

Examples of the solvent include the solvents exemplified above as the solvent. The pressure-sensitive adhesive may contain a light diffusing agent. The light diffusing agent is an additive that imparts light diffusing properties to the pressure-sensitive adhesive, and may be fine particles having a refractive index different from the refractive index of the polymer contained in the pressure-sensitive adhesive. Light diffusing agents include fine particles made of inorganic compounds and fine particles made of organic compounds (polymers). Since many of the polymers contained as active ingredients in the adhesive, including acrylic polymers, have a refractive index of about 1.4 to 1.6, the light diffusing agent whose refractive index is 1.2 to 1.8 It is preferable to select them appropriately. The refractive index difference between the polymer contained as an active ingredient in the pressure-sensitive adhesive and the light diffusing agent is usually 0.01 or more, and preferably 0.01 to 0.2 from the viewpoint of the brightness and displayability of the display device. The microparticles used as the light diffusing agent are preferably spherical microparticles, more preferably microparticles close to monodisperse, and more preferably microparticles having an average particle diameter of 2 μm to 6 μm. The refractive index is measured by the common minimum deviation method or Abbe refractometer.
Fine particles made of inorganic compounds include aluminum oxide (refractive index: 1.76) and silicon oxide (refractive index: 1.45). Examples of fine particles made of organic compounds (polymers) include melamine beads (refractive index 1.57), polymethyl methacrylate beads (refractive index 1.49), methyl methacrylate/styrene copolymer resin beads (refractive index 1.50 ~1.59), polycarbonate beads (refractive index 1.55), polyethylene beads (refractive index 1.53), polystyrene beads (refractive index 1.6), polyvinyl chloride beads (refractive index 1.46), and silicone Resin beads (refractive index 1.46) and the like can be mentioned. The content of the light diffusing agent is usually 3 to 30 parts by mass with respect to 100 parts by mass of the polymer.
The thickness of the pressure-sensitive adhesive is determined according to its adhesive strength and the like, and is not particularly limited, but is usually 1 μm to 40 μm. The thickness is preferably 3 μm to 25 μm, more preferably 5 μm to 20 μm, from the viewpoint of workability, durability, and the like. By setting the thickness of the adhesive layer formed from the adhesive to 5 μm to 20 μm, brightness is maintained when the display device is viewed from the front or obliquely, and blurring and blurring of the displayed image are suppressed. can be made difficult.

[Dry-hardening adhesive]
The drying-hardening adhesive may contain a solvent.
The dry-hardening adhesive contains a polymer of a monomer having a protic functional group such as a hydroxyl group, a carboxyl group, or an amino group and an ethylenically unsaturated group, or a urethane resin as a main component, and furthermore, a polyvalent Examples include compositions containing cross-linking agents or curing compounds such as aldehydes, epoxy compounds, epoxy resins, melamine compounds, zirconia compounds, and zinc compounds. Polymers of monomers having a protic functional group such as a hydroxyl group, a carboxyl group, or an amino group and an ethylenically unsaturated group include ethylene-maleic acid copolymers, itaconic acid copolymers, acrylic acid copolymers, and acrylamide. Copolymers, saponified products of polyvinyl acetate, polyvinyl alcohol resins, and the like can be mentioned.

Polyvinyl alcohol resins include polyvinyl alcohol, partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol. mentioned. The content of the polyvinyl alcohol-based resin in the water-based adhesive is usually 1-10 parts by mass, preferably 1-5 parts by mass, per 100 parts by mass of water.

Examples of urethane resins include polyester-based ionomer-type urethane resins. The polyester-based ionomer-type urethane resin referred to here is a urethane resin having a polyester skeleton, and is a resin into which a small amount of an ionic component (hydrophilic component) has been introduced. Since the ionomer-type urethane resin is emulsified in water to form an emulsion without using an emulsifier, it can be used as a water-based pressure-sensitive adhesive. When using a polyester-based ionomer-type urethane resin, it is effective to blend a water-soluble epoxy compound as a cross-linking agent.

Examples of epoxy resins include polyamide epoxy resins obtained by reacting epichlorohydrin with polyamide polyamines obtained by reacting polyalkylenepolyamines such as diethylenetriamine or triethylenetetramine with dicarboxylic acids such as adipic acid. Commercially available polyamide epoxy resins include "Sumireze Resin (registered trademark) 650" and "Sumireze Resin 675" (manufactured by Sumika Chemtex Co., Ltd.) and "WS-525" (manufactured by Japan PMC Co., Ltd.). etc. When an epoxy resin is blended, the amount added is usually 1 to 100 parts by mass, preferably 1 to 50 parts by mass, per 100 parts by mass of the polyvinyl alcohol resin.

The thickness of the adhesive layer formed from the drying-hardening adhesive is usually 0.001 μm to 5 μm, preferably 0.01 μm to 2 μm, more preferably 0.01 μm to 0.5 μm. be. If the pressure-sensitive adhesive layer formed from the drying-hardening adhesive is too thick, the optically anisotropic layer tends to have poor appearance.

[Active energy ray-curable adhesive]
The active energy ray-curable adhesive may contain a solvent. An active energy ray-curable adhesive is an adhesive that is cured by being irradiated with an active energy ray.
The active energy ray-curable adhesive includes a cationic polymerizable adhesive containing an epoxy compound and a cationic polymerization initiator, a radically polymerizable adhesive containing an acrylic curing component and a radical polymerization initiator, and an epoxy compound. An adhesive containing both a cationic polymerizable curing component such as an acrylic compound and a radically polymerizable curing component such as an acrylic compound, and further containing a cationic polymerization initiator and a radical polymerization initiator, and these polymerization initiators Examples include an adhesive that is cured by irradiating an electron beam without being exposed.

Among them, a radically polymerizable active energy ray-curable adhesive containing an acrylic curing component and a radical polymerization initiator, and a cationically polymerizable active energy ray-curable adhesive containing an epoxy compound and a cationic polymerization initiator. preferable. Examples of acrylic curing components include (meth)acrylates such as methyl (meth)acrylate and hydroxyethyl (meth)acrylate, and (meth)acrylic acid. The active energy ray-curable adhesive containing an epoxy compound may further contain a compound other than the epoxy compound. Examples of compounds other than epoxy compounds include oxetane compounds and acrylic compounds.
Examples of radical polymerization initiators include the photopolymerization initiators described above. Commercially available cationic polymerization initiators include "Kayarad" (registered trademark) series (manufactured by Nippon Kayaku Co., Ltd.), "Cyracure UVI" series (manufactured by Dow Chemical Co., Ltd.), "CPI" series (manufactured by San-Apro Co., Ltd.), "TAZ", "BBI" and "DTS" (manufactured by Midori Chemical Co., Ltd.), "Adeka Optomer" series (manufactured by ADEKA Corporation), "RHODORSIL" (registered trademark) (manufactured by Rhodia Corporation), etc. be done. The content of the radical polymerization initiator and the cationic polymerization initiator is usually 0.5 parts by mass to 20 parts by mass, preferably 1 part by mass to 15 parts by mass, with respect to 100 parts by mass of the active energy ray-curable adhesive. Department.

Active energy ray-curable adhesives further contain ion trapping agents, antioxidants, chain transfer agents, tackifiers, thermoplastic resins, fillers, flow control agents, plasticizers, antifoaming agents, and the like. may

As used herein, the active energy ray is defined as an energy ray capable of decomposing a compound that generates active species to generate active species. Such active energy rays include visible light, ultraviolet rays, infrared rays, X-rays, α-rays, β-rays, γ-rays and electron beams, with ultraviolet rays and electron beams being preferred. Preferred ultraviolet irradiation conditions are the same as those for the polymerization of the polymerizable liquid crystal compound described above.

[Display device]
The present invention can provide a display device including the optical film of the present invention as one embodiment. Further, the display device may include the elliptically polarizing plate according to the embodiment.
The display device is a device having a display mechanism, and includes a light-emitting element or a light-emitting device as a light source. Examples of display devices include liquid crystal displays, organic electroluminescence (EL) displays, inorganic electroluminescence (EL) displays, touch panel displays, electron emission displays (field emission displays (FED, etc.), surface field emission displays). (SED)), electronic paper (display device using electronic ink or electrophoretic element), plasma display device, projection display device (grating light valve (GLV) display device, display device having digital micromirror device (DMD) etc.) and piezoelectric ceramic displays. The liquid crystal display device includes any of a transmissive liquid crystal display device, a transflective liquid crystal display device, a reflective liquid crystal display device, a direct view liquid crystal display device, a projection liquid crystal display device, and the like. These display devices may be display devices that display two-dimensional images, or may be stereoscopic display devices that display three-dimensional images. In particular, an organic EL display device and a touch panel display device are preferable as the display device comprising the optical film of the present invention and a polarizing plate.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples. In addition, "%" and "parts" in the examples mean % by mass and parts by mass unless otherwise specified. In addition, the polymer films, devices and measuring methods used in the following examples are as follows.

・ZF-14 manufactured by Nippon Zeon Co., Ltd. was used as the cycloolefin polymer (COP) film.
・AGF-B10 manufactured by Kasuga Denki Co., Ltd. was used as the corona treatment device.
- The corona treatment was performed once under the conditions of an output of 0.3 kW and a treatment speed of 3 m/min using the above corona treatment apparatus.
・SPOT CURE SP-9 with a polarizer unit manufactured by Ushio Inc. was used as a polarized UV irradiation device.
- Unicure VB-15201BY-A manufactured by Ushio Inc. was used as the high-pressure mercury lamp.
・The in-plane retardation value Re(λ) was measured using KOBRA-WPR manufactured by Oji Scientific Instruments Co., Ltd.
The retardation value Rth(λ) in the thickness direction and the film thickness were measured using an ellipsometer M-220 manufactured by JASCO Corporation.

[Preparation of Alignment Film Composition for Forming First Retardation Layer]
5 parts of a photo-alignable material having the following structure (weight average molecular weight: 30000) and 95 parts of cyclopentanone (solvent) were mixed as components, and the resulting mixture was stirred at 80°C for 1 hour to obtain a first An alignment film composition for forming a retardation layer was obtained.

[Preparation of Alignment Film Composition for Forming Second Retardation Layer]
A silane coupling agent KBE-9103 manufactured by Shin-Etsu Chemical Co., Ltd. is dissolved in a mixed solvent in which ethanol and water are mixed at a ratio of 9: 1 (weight ratio) to form a second retardation layer with a solid content of 1%. An alignment film composition for was obtained.

[Preparation of compositions for forming first and second retardation layers (compositions I to IV)]
0.1 part of a leveling agent (F-556; manufactured by DIC) and a polymerization initiator 2-dimethylamino-2- 6 parts of benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369 (Irg369); manufactured by BASF Japan Ltd.) were added.
Further, by adding N-methyl-2-pyrrolidone (NMP) as a solvent so that the solid content concentration is 13% and stirring at 80 ° C. for 1 hour, the first and second retardation layer formation A composition was obtained. The mixture ratio of the polymerizable liquid crystal compound A and the polymerizable liquid crystal compound B is added as shown in Table 1 according to the desired wavelength dispersion value α, and the names of each composition are shown in Table 1. As written.

※重合性液晶化合物Ａ、及びＢの比率は、重合性液晶化合物総量に対する比率とする。

* The ratio of polymerizable liquid crystal compounds A and B is the ratio to the total amount of polymerizable liquid crystal compounds.

Polymerizable liquid crystal compound A was produced by the method described in JP-A-2010-31223. Polymerizable liquid crystal compound B was produced according to the method described in JP-A-2009-173893. Each molecular structure is shown below.

Polymerizable liquid crystal compound A

Polymerizable liquid crystal compound B

[Preparation of Liquid Crystal Compositions for Forming First and Second Retardation Layers (Composition V)]
0.1 part of the leveling agent F-556 and 3 parts of the polymerization initiator Irg369 are added to the liquid crystal compound LC242 described below: Paliocolor LC242 (registered trademark of BASF) so that the solid content concentration becomes 13%. cyclopentanone was added to obtain liquid crystal compositions for forming the first and second retardation layers. The liquid crystal composition thus obtained is named "Composition V".
Liquid crystal compound LC242: Paliocolor LC242 (BASF registered trademark)

(Example 1)
[Manufacture of first retardation layer]
On COP film (ZF-14-50) manufactured by Nippon Zeon Co., Ltd., the alignment film composition for forming the first retardation layer was applied with a bar coater, dried at 80 ° C. for 1 minute, and polarized UV irradiation equipment ( Using SPOT CURE SP-9 (manufactured by Ushio Inc.), polarized UV exposure was performed at a wavelength of 313 nm and an integrated light amount of 100 mJ/cm ² at an axial angle of 45°. The thickness of the obtained first alignment film for forming a retardation layer was measured with an ellipsometer and found to be 100 nm.
Subsequently, the composition I was applied to the first alignment film for forming the retardation layer using a bar coater and dried at 120° C. for 1 minute. (manufactured by the company), the first retardation layer is formed by irradiating ultraviolet rays from the side on which the composition of the retardation layer is applied (in a nitrogen atmosphere, integrated light amount at a wavelength of 365 nm: 500 mJ / cm ² ). did. The film thickness of the obtained first alignment film for forming a retardation layer was measured with an ellipsometer and found to be 2.3 μm.

[Production of Second Retardation Layer]
On COP film (ZF-14-50) manufactured by Nippon Zeon Co., Ltd., the alignment film composition for forming the second retardation layer is applied with a bar coater, dried at 120 ° C. for 1 minute, and the second retardation An alignment film for layer formation was obtained. The film thickness of the obtained second alignment film for forming the retardation layer was measured with an ellipsometer and found to be 200 nm.
Subsequently, the composition I was applied to the second alignment film for forming the retardation layer using a bar coater and dried at 120° C. for 1 minute. (manufactured by the company), the second retardation layer is formed by irradiating ultraviolet rays from the side on which the composition of the retardation layer is applied (in a nitrogen atmosphere, integrated light amount at a wavelength of 365 nm: 500 mJ / cm ² ). did. The film thickness of the obtained second alignment film for forming the retardation layer was measured with an ellipsometer and found to be 1.2 μm.

[Re measurement of first retardation layer and second retardation layer]
The in-plane retardation values (Re1(λ) and Re2(λ)) of the first retardation layer and the second retardation layer produced by the above method are the substrate cycloolefin polymer film. After confirming that there were no such particles, measurement was performed at wavelengths λ of 450 nm, 550 nm and 650 nm using a measuring instrument (KOBRA-WR, manufactured by Oji Keisokuki Co., Ltd.). Table 2 shows the results obtained.

[Rth measurement of first retardation layer and second retardation layer]
The thickness direction retardation values (Rth1 (λ) and Rth2 (λ)) of the first retardation layer and the second retardation layer produced by the above method are the substrate cycloolefin polymer film. After confirming that there was no such phenomenon, measurement was performed by changing the angle of incidence of light on the sample using an ellipsometer. Further, the average refractive index at wavelengths λ of 450 nm and 550 nm was measured using a refractometer (manufactured by Atago Co., Ltd., "multi-wavelength Abbe refractometer DR-M4"). Table 2 shows Rth1(λ) and Rth2(λ) at wavelengths λ of 450 nm and 550 nm calculated from the obtained film thickness, average refractive index, and ellipsometer measurement results.

[Calculation of Nz (λ)]
Nz(λ) of the optical film having the first retardation layer and the second retardation layer laminated was calculated according to the formula (C). Table 2 shows the calculated results.

The refractive indices nx1(λ), ny1(λ), and nz1(λ) of the obtained first retardation layer are nx1(λ)>ny1(λ)≈nz1 in the entire wavelength range λ=400 to 700 nm. (λ). Further, the refractive indices nx2(λ), ny2(λ), and nz2(λ) of the second retardation layer are nz2(λ)>nx2(λ)≈ny2(λ) in the entire wavelength range λ=400 to 700 nm. meet.

[Manufacture of polarizing plate]
A polyvinyl alcohol film having an average degree of polymerization of about 2,400, a degree of saponification of 99.9 mol% or more, and a thickness of 75 µm was immersed in pure water at 30°C. It was iodine dyed by immersing it in an aqueous solution of 02/2/100 at 30° C. (iodine dyeing step). The polyvinyl alcohol film that had undergone the iodine dyeing process was immersed in an aqueous solution with a weight ratio of potassium iodide/boric acid/water of 12/5/100 at 56.5°C to carry out boric acid treatment (boric acid treatment process ). After the polyvinyl alcohol film that had undergone the boric acid treatment step was washed with pure water at 8°C, it was dried at 65°C to obtain a polarizer (thickness after stretching: 27 µm) in which iodine was adsorbed and oriented in the polyvinyl alcohol. . At this time, stretching was performed in the iodine dyeing process and the boric acid treatment process. The total draw ratio in this drawing was 5.3 times. The obtained polarizer and a saponified triacetyl cellulose film (KC4UYTAC, 40 μm, manufactured by Konica Minolta) were bonded with a nip roll via a water-based adhesive. The resulting laminate was dried at 60° C. for 2 minutes while maintaining a tension of 430 N/m to obtain a polarizing plate having a triacetyl cellulose film as a protective film on one side. The water-based adhesive consists of 100 parts of water, 3 parts of carboxyl group-modified polyvinyl alcohol (Kuraray Poval KL318 manufactured by Kuraray Co., Ltd.), and a water-soluble polyamide epoxy resin (Sumilez Resin 650 manufactured by Sumika Chemtex, an aqueous solution with a solid concentration of 30%). 1.5 parts were added and prepared.

The optical properties of the obtained polarizing plate were measured. The measurement was performed with a spectrophotometer (V7100, manufactured by JASCO Corp.) using the polarizer surface of the polarizing plate obtained above as an incident surface. The resulting luminosity-correction single transmittance was 42.1%, the luminosity-correction polarization degree was 99.996%, the single hue a was −1.1, and the single hue b was 3.7.

[Production of Elliptical Polarizing Plate]
First, the surface of the first retardation layer coated with the polymerizable liquid crystal compound was subjected to corona treatment, and then an adhesive (5 μm pressure-sensitive adhesive manufactured by Lintec Corporation) was applied to the polarizing plate produced by the method described above. ), the substrate was peeled off to form a laminate of the polarizing plate and the first retardation layer. Subsequently, after performing corona treatment on the polymerizable liquid crystal compound-coated surface of the second retardation layer, the polarizing plate and the first retardation layer are attached via an adhesive (pressure-sensitive adhesive, 5 μm, manufactured by Lintec Co., Ltd.). The first retardation layer and the second retardation layer in the laminate of layers were laminated. After that, the substrate was peeled off to produce an elliptically polarizing plate.

[Confirmation of frontal hue and oblique hue change]
The obtained elliptically polarizing plate was attached to a mirror via an adhesive, and then visually observed at a distance of 50 cm from the front to confirm the hue. Further, the oblique hue was confirmed by visual observation at a distance of 50 cm from the direction of elevation angle 60° and azimuth angle 0 to 360°. Table 2 shows the confirmed results.
The front hue and oblique hue are as follows.
◎: clear black, ○: black, △: red or bluish black, ×: red or blue

(Examples 2 to 30, Comparative Examples 1 to 12)
An optical film and an elliptically polarizing plate were produced in the same manner as in Example 1, except that Composition I was changed to Composition II, Composition III, Composition IV, or Composition V according to Table 2, respectively. Table 2 shows the respective measurement results.
The refractive indices nx1(λ), ny1(λ) and nz1(λ) of the first retardation layers obtained in Examples 2 to 30 were nx1(λ )>ny1(λ)≈nz1(λ). Further, the refractive indices nx2(λ), ny2(λ), and nz2(λ) of the second retardation layer are nz2(λ)>nx2(λ)≈ny2(λ) in the entire wavelength range λ=400 to 700 nm. meet.

(Example 31)
The composition I is changed according to the description in Table 2, and the lamination order of the first retardation layer and the second retardation layer in the method for producing an elliptically polarizing plate is set to the polarizing plate and the second retardation layer first. After lamination, an optical film and an elliptically polarizing plate were prepared in the same manner as in Example 1 except that the order of laminating the polarizing plate, the second retardation layer laminate and the first retardation layer was changed. Table 2 shows the measurement results.
The refractive indices nx1(λ), ny1(λ) and nz1(λ) of the first retardation layer obtained in Example 31 are nx1(λ)>ny1( λ)≈nz1(λ). Further, the refractive indices nx2(λ), ny2(λ), and nz2(λ) of the second retardation layer are nz2(λ)>nx2(λ)≈ny2(λ) in the entire wavelength range λ=400 to 700 nm. meet.

The elliptically polarizing plate having the first retardation layer and the second retardation layer described in Examples has black in the normal hue and oblique hue, and has excellent antireflection properties.

Claims (9)

The retardation layer is an optical film consisting of a first retardation layer and a second retardation layer,
satisfying the relationships of the following formulas (1) and (2),
0.4≦Nz(450)≦0.6 (1)
0.4≦Nz(550)≦0.6 (2)
[In the formula, Nz (450) represents the Nz coefficient of the optical film for light with a wavelength λ = 450 nm, Nz (550) represents the Nz coefficient of the optical film for light with a wavelength λ = 550 nm, and the wavelength λ (nm) The Nz coefficient Nz(λ) of the optical film for light is Nz(λ)=(nx(λ)−nz(λ))/(nx(λ)−ny(λ))
is indicated by nx(λ) represents the principal refractive index in the direction parallel to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the optical film. ny(λ) is the refraction in the refractive index ellipsoid formed by the optical film in a direction parallel to the film plane and orthogonal to the direction of nx(λ) for light of wavelength λ (nm) represents a rate.
nz(λ) represents the refractive index of the refractive index ellipsoid formed by the optical film in the direction perpendicular to the plane of the film for light of wavelength λ (nm). ]
The first retardation layer is
nx1(λ)>ny1(λ)≈nz1(λ) in the range of wavelength λ=400 to 700 nm in the refractive index ellipsoid formed by the first retardation layer
[In the formula, nx1(λ) represents the principal refractive index in the direction parallel to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the first retardation layer. ny1 (λ) is a wavelength λ (nm) in a direction parallel to the film plane and perpendicular to the direction of the nx1 (λ) in the refractive index ellipsoid formed by the first retardation layer represents the refractive index for light. nz1(λ) represents the refractive index in the direction perpendicular to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the first retardation layer. ]
having a relationship of the following formulas (3), (4) and (7)
0.82≤Re1(450)/Re1(550)≤1.00 (3)
1.00≤Re1(650)/Re1(550) (4)
120nm≦Re1(550)≦170nm (7)
[In the formula, Re1 (450) is the in-plane retardation value of the first retardation layer for light with a wavelength λ = 450 nm, and Re1 (550) is the in-plane position of the first retardation layer for light with a wavelength λ = 550 nm. Re1(650) indicates the in-plane retardation value of the first retardation layer for light with a wavelength λ=650 nm, and Re1(λ )teeth,
Re1(λ)=(nx1(λ)−ny1(λ))×d1
is represented by Here, d1 represents the thickness of the first retardation layer. ],
The thickness is 5 μm or less ,
The second retardation layer is
In the range of wavelength λ = 400 to 700 nm in the refractive index ellipsoid formed by the second retardation layer,
nz2(λ)>nx2(λ)≈ny2(λ)
[In the formula, nz2(λ) represents the refractive index in the direction perpendicular to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the second retardation layer. nx2(λ) represents the maximum refractive index in the direction parallel to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the second retardation layer. ny2 (λ) is parallel to the film plane in the refractive index ellipsoid formed by the second retardation layer, and for light with a wavelength λ (nm) in a direction perpendicular to the direction of nx2 Represents refractive index. However, when nx2(λ)=ny2(λ), nx2(λ) represents the refractive index in any direction parallel to the film plane. ]
have a relationship of
Formulas (5), (6) and (8) below
Rth2(450)/Rth2(550)≤1.00 (5)
1.00≦Rth2(650)/Rth2(550) (6)
−100 nm≦Rth2(550)≦−50 nm (8)
[ In the formula, Rth2 (450) is the retardation value in the thickness direction of the second retardation layer for light with a wavelength λ = 450 nm, and Rth2 (550) is the second retardation layer for light with a wavelength λ = 550 nm. The retardation value in the thickness direction, Rth2 (650) represents the retardation value in the thickness direction of the second retardation layer for light with a wavelength of 650 nm, and the second retardation layer for light with a wavelength of λ (nm). The retardation value Rth2(λ) in the thickness direction is
Rth2(λ)=[(nx2(λ)+ny2(λ))/2−nz2(λ)]×d2
is represented by Here, in the refractive index ellipsoid formed by the second retardation layer, nz2 (λ) represents the principal refractive index in the direction perpendicular to the film plane at the wavelength λ (nm), ((nx2 (λ) + ny2 (λ))/2) represents the average refractive index in the plane of the film at the wavelength λ (nm). d2 represents the thickness of the second retardation layer. ] has an optical characteristic represented by
thickness is 5 μm or less,
optical film. 2. The optical film according to claim 1, wherein the second retardation layer is a film comprising a coating layer formed by polymerizing a polymerizable liquid crystal in an oriented state. 3. The optical film according to claim 1, wherein the first retardation layer is a film comprising a coating layer formed by polymerizing a polymerizable liquid crystal in an oriented state. The optical film according to any one of claims 1 to 3 , wherein the first retardation layer and the second retardation layer are coating layers formed by mainly polymerizing the same polymerizable liquid crystal compound. The optical film according to any one of claims 1 to 4 and a polarizing plate, wherein the polarizing plate, the adhesive layer, the first retardation layer, the adhesive layer, and the second retardation layer are arranged in this order. An elliptically polarizing plate with an optical compensation function, which is a formed optical laminate. The optical film according to any one of claims 1 to 4 and a polarizing plate, wherein the polarizing plate, the adhesive layer, the second retardation layer, the adhesive layer, and the first retardation layer are arranged in this order. An elliptically polarizing plate with an optical compensation function, which is a formed optical laminate. The absorption axis of the polarizing plate and the slow axis of the first retardation layer have a relationship of 45±5° or 135±5° in the plane of the film, and the absorption axis of the polarizing plate and the first retardation layer 7. The elliptically polarizing plate with an optical compensation function according to claim 5 , wherein the slow axis of the second retardation layer and the slow axis of the second retardation layer are perpendicular to the film surface in the vertical direction. An organic EL display device comprising the elliptically polarizing plate with optical compensation function according to any one of claims 5 to 7 . 8. The method for producing an elliptically polarizing plate with an optical compensation function according to any one of claims 5 to 7 , comprising all of the following steps.
(Step 1-A) A step of forming a first retardation layer by coating a polymerizable liquid crystal compound on a base material on which a horizontal alignment film is formed and then polymerizing the compound in a horizontally aligned state;
(Step 1-B) A step of forming a second retardation layer by coating a polymerizable liquid crystal compound on a base material on which a vertical alignment film is formed and then polymerizing the compound in a vertically aligned state;
(Step 2) A step of transferring the liquid crystal polymer of the first retardation layer and the liquid crystal polymer of the second retardation layer from the substrate via an adhesive and laminating them on the polarizing plate.