JP5446415B2 - Liquid crystal display - Google Patents

Description

The present invention is a color filter on array (C olor Filter O n A rray , hereinafter referred to as "COA") relates to a liquid crystal display device comprising a substrate, in particular, the COA substrate having a slit in the pixel electrode on the color layer The present invention relates to a liquid crystal display device provided.

  The liquid crystal display device is a display element that utilizes the birefringence of liquid crystal molecules, and includes a liquid crystal cell, a polarizing element, and an optical compensation layer. Such a liquid crystal display device is roughly classified into a transmission type having a light source inside and a reflection type having a structure using an external light source, depending on the type of light source.

  The transmissive liquid crystal display device has a configuration in which two polarizing elements are arranged on both sides of a liquid crystal cell, and one or two optical compensation layers are provided between the liquid crystal cell and the polarizing element. The reflective liquid crystal display device has a configuration in which a reflector, a liquid crystal cell, one optical compensation layer, and one polarizing element are arranged in this order.

  In the liquid crystal cell, rod-like liquid crystal molecules sandwiched between two substrates are aligned and sealed, and a voltage is applied to the electrode layers disposed on both sides or one side of the two substrates, thereby producing a rod-like liquid crystal. This is a mechanism for switching light transmission / light-shielding by changing the orientation state of the active molecule.

  The liquid crystal cell is different in the alignment state of rod-like liquid crystalline molecules. Various display modes such as STN (Supper Twisted Nematic), VA (Vertically Aligned), and HAN (Hybrid Aligned Nematic) have been proposed.

  In general, the polarizing element has two transparent protective films made of triacetyl cellulose (hereinafter referred to as TAC) attached to both sides of a polarizing film obtained by diffusing iodine in polyvinyl alcohol (hereinafter referred to as PVA). It has a configuration.

  Various optical compensation layers have been proposed. For example, in a VA mode liquid crystal display device having good display characteristics in a range of a high viewing angle, nx with respect to three-dimensional main refractive indexes nx, ny, and nz. A biaxial retardation film having a refractive index ellipsoid represented by ≧ ny> nz is used in combination (for example, see Non-Patent Document 1).

  In recent years, liquid crystal display devices have been evaluated for their space-saving, light-weight, and power-saving properties due to their thinness, and they are rapidly expanding as television viewers, as well as brightness, contrast, and visibility in all directions. There is a strong demand to further improve display performance. In addition, a technique has been adopted in which the contrast is improved by increasing the update period (liquid crystal drive frequency) of the video signal applied to the liquid crystal display device.

  Specifically, as a TV application, first, in order to improve the aperture ratio of pixels with respect to luminance, and in addition to eliminate the influence of parallax caused by the cell gap of the liquid crystal panel, a COA provided with a color filter on the array substrate Liquid crystal display devices having a structure have been put into practical use. Next, for improving display performance such as contrast and omni-directional visibility, normally black mode IPS and VA liquid crystal display devices capable of higher contrast and wide viewing angle display are particularly preferred and used. In addition, the above-described optical compensation layer is also used so as to be colored when displaying black when viewed from the front or designed to minimize color change when viewed from an oblique direction.

  The array substrate refers to a substrate on which active elements for driving liquid crystals such as TFT (Thin Film Transistor) and MIM (metal / insulating film / metal) are formed. The liquid crystal panel usually has a configuration in which a counter substrate in which a color filter is formed on a transparent substrate and an array substrate are opposed to each other, and the liquid crystal is sandwiched therebetween. Various TFTs have been proposed, such as those using amorphous silicon or a polysilicon thin film, those using a transparent oxide semiconductor, or those using carbon nanotubes.

  Next, a COA structure liquid crystal display device in which a color filter is formed on the array substrate side will be described.

  Usually, in the configuration in which the color filter is provided on the counter substrate, it is difficult to control the alignment between the array substrate and the counter substrate with high accuracy. Therefore, a black matrix (Black Matrix, hereinafter referred to as “BM”) provided in the color filter is difficult. The light-shielding portion called “)” has to be provided widely, which hinders the improvement of the aperture ratio.

  On the other hand, as a technique for improving the aperture ratio, an insulating layer having a thickness of 2 to 3 μm is formed of an organic material on the wiring on the array substrate, and the wiring on the array substrate and the pixel electrode are arranged in separate layers. There is a method of reducing the coupling capacitance generated between the wiring and the electrode and eliminating the planar gap between the two. However, in this case, it is necessary to form an insulating layer, which is disadvantageous in terms of cost.

  In the COA structure, the color filter can also serve as the insulating layer. The alignment of the array substrate and the counter substrate is not necessary, and the aperture ratio is improved by reducing the BM width. It has both advantages of improving the aperture ratio.

  FIG. 4 shows a liquid crystal display device having a COA structure, which has a wide viewing angle and is controlled so that the alignment direction of the liquid crystal molecules in one pixel is a plurality of directions, and is a liquid crystal display device of an alignment division vertical alignment method. It is explanatory drawing which showed typically the cross section of an example (it is called VA or MVA (Multi-domain Vertical Alignment)).

  As shown in FIG. 4, this MVA liquid crystal display device has a configuration in which a counter substrate 1 and a COA substrate 2 are arranged to face each other with a liquid crystal layer 4 interposed therebetween. The counter substrate 1 has a configuration in which a common electrode 13 having a slit 14 is provided on a glass substrate 11, and the COA substrate 2 has a thin film transistor layer 3, a colored layer 23, a pixel electrode 24, and a protrusion 25 on the glass substrate 21. Is provided.

  In addition, polarizing plates 12 and 22 are provided on the opposite side, that is, the outer side, of the opposing substrate 1 and the COA substrate 2, and the alignment films 15 and 27 are provided on the opposing surface, that is, the surface in contact with the liquid crystal layer 4. Is formed.

  Protrusions 25 are provided on the pixel electrodes 24, and the protrusions 25 and the slits 14 provided in the common electrode 13 have a role of regulating the alignment of the liquid crystal and are provided at alternate positions in one pixel. . These protrusions 25 and slits 14 have a function of assisting the vertical alignment of liquid crystal molecules. The liquid crystal display device configured as described above controls the alignment of liquid crystal molecules by providing protrusions and slits instead of rubbing treatment.

  The edge of the slit 14 of the common electrode 13 has an effect of controlling the orientation in the same manner as the orientation control protrusion 25 because the distortion of the electric field generated in the vicinity of the edge affects the orientation.

  On the other hand, when the slit 26 is formed instead of forming the protrusion 25 as in the liquid crystal display device shown in FIG. 5, light leakage from this portion is reduced because there is no protrusion that tilts the liquid crystal molecules, Contrast improves.

  The pixel electrode 24 is a transparent conductive film made of ITO (indium tin oxide), zinc oxide, tin oxide, gallium oxide or the like, and the slit 26 is formed by photoetching of the pixel electrode 24. However, in the COA substrate 2 having the above structure, since the slit 26 exists on the colored layer 23 constituting the pixel, there is a problem that the liquid crystal layer 4 is directly affected by the electrical characteristics of the material of the colored layer 23. is there. That is, the colored layer 23 is exposed in the slit 26, and the liquid crystal layer 4 and the colored layer 23 are in direct contact with each other. In the COA substrate 2, since each pixel electrode 24 is individually driven by each active element, it is necessary to remove the transparent conductive film between the pixels to form the pixel electrode 24. The exposed portion of the colored layer 23 is called an opening.

  In fact, when the conventional colored layer material is used, the MVA type or IPS type liquid crystal display device has various display defects such as a liquid crystal alignment defect due to the electrical characteristics of the colored layer material and a burn-in phenomenon due to a deviation in switching threshold. It was happening. Therefore, when a colored layer made of a conventional colored layer material is used for an MVA type or IPS type liquid crystal display device, a protective layer (overcoat layer) made of a transparent resin is provided on the colored layer so that the liquid crystal sandwiching surface and the colored layer are directly It was necessary to avoid touching.

  However, in recent years, the cost of liquid crystal display devices has been remarkably reduced, and the color pixel forming process, which is the manufacturing process thereof, has been urged to reduce the price. As described above, by providing an overcoat layer of a transparent resin, it is possible to use a conventional colored layer material for an MVA type liquid crystal display device, but various display defects occur even when an overcoat layer is used. (For example, refer to Patent Document 1 and Patent Document 2).

  Further, both the coloring layer material and the overcoat layer material have been improved so as to be compatible with the MVA type liquid crystal display device, but in order to ensure higher image quality than a large TV, the overcoat layer is 2 μm in some cases. It is also necessary to provide the thickness as described above, which causes a problem that it is difficult to apply uniformly, which is one factor that hinders cost reduction in terms of yield. In addition, the material cost and the decrease in yield due to the increase in the process are also factors that hinder the price reduction, and there has been a demand for a colored layer that can be used in an MVA type or IPS type liquid crystal display device without providing an overcoat layer. However, it was difficult to realize due to the problems described above.

  Further, in the COA substrate, it is necessary to provide a spatial distance so that the voltage change of the signal line does not affect the pixel electrode. When parasitic capacitance coupling occurs, display defects such as RC delay in which electrical signals flowing through the wiring interfere with each other to cause a delay in the signal and crosstalk in which the electrical signal flows to other wirings occur. Even if a sufficient distance is provided between the signal line and the pixel electrode, if the dielectric constant of the colored pixel existing between the signal line and the pixel electrode is too high, parasitic capacitance coupling occurs between the wirings, causing RC delay and crosstalk. There was a cause.

  Next, MVA (synonymous with VA) and IPS liquid crystal display devices for improving display performance such as contrast and omnidirectional visibility will be described below.

  There are approximately two liquid crystal alignment methods that can ensure contrast with a wide viewing angle: homogeneous (parallel to the substrate surface) alignment in the absence of an electric field, and homeotropic (perpendicular to the substrate surface) alignment in the absence of an electric field. Can be divided into The former includes liquid crystal display devices such as IPS mode, FFS mode, and FLC mode. A typical example of the latter is a VA mode liquid crystal display device.

  In Patent Document 7 to be described later, a plurality of phase differences in which a first optical compensation layer has a refractive index distribution of nx> ny ≧ nz and a second optical compensation layer has a refractive index distribution of nx = ny> nz. It has been proposed to apply a technique using a film to a VA mode liquid crystal display device. Patent Document 8 discloses a plurality of retardation films in which a first optical compensation layer has a refractive index distribution of nx = ny> nz and a second optical compensation layer has a refractive index distribution of nz = nx ≧ ny. It has been proposed to apply the technique used to an IPS mode liquid crystal display device.

  In general, the optical compensation layer used in the above-described VA mode or IPS mode liquid crystal display device is a biaxial retardation film formed by stretching in a biaxial direction, or a polymerizable liquid crystal and / or In most cases, the retardation film is formed by applying a non-polymerizable liquid crystal material, and is controlled at the level of advanced display quality required for the three-dimensional main refractive index nx, ny, nz. It was difficult to manufacture.

  Specifically, not only the birefringence of the liquid crystal material but also the thickness direction retardation values (hereinafter referred to as Rth (R), Rth (G), Rth) of the red, green and blue colored pixel layers constituting the color filter. (B)), it is necessary to determine and manufacture the three-dimensional main refractive index of the optical compensation layer, and an in-plane retardation value represented by two parameters nx and ny, In addition to simultaneously controlling the thickness direction retardation value represented by the three parameters nx, ny, and nz with high accuracy, wavelength dispersion of the birefringence of the liquid crystal material, and red, green, and It is difficult to provide the optical compensation layer with wavelength dispersion that compensates for both the thickness direction retardation values of light in the red region, the green region, and the blue region of each colored pixel layer of blue. In the liquid crystal display device, it is still the most Not be said to have been designed in such value.

  As a result, the visibility from the front (vertical direction) with respect to the display surface is good, but the optical observation is not optimally compensated for the visibility observed from an oblique angle such as 45 degrees (hereinafter abbreviated as oblique visibility). Only certain colors will leak light, and when black is displayed, colors such as reddish, bluedish, or greenish will be produced.

  Since the retardation of a color filter composed of a plurality of colored layers is relatively small compared to other members used in a liquid crystal display device, the retardation of the color filter is hardly considered in the conventional liquid crystal display device. However, the compensation performance of the optical compensation layer was designed, but it has become a level that cannot be ignored in liquid crystal televisions that require high contrast and wide viewing angle characteristics.

  In particular, high-contrast liquid crystal display devices having 1000 or 3000 or more have been required to have high image quality required for black display.

  On the other hand, the colored polymer thin film contains a polymer having a planar structure group in the side chain, or the colored polymer thin film contains birefringence reducing particles having birefringence opposite to that of the polymer. Thus, attempts have been made to reduce the amount of retardation of the color filter (see, for example, Patent Documents 1 and 2).

  In addition, the in-plane retardation of the blue region of the color filter is made larger than that of the green and red regions, thereby increasing the amount of blue leakage light and offsetting the yellowing that is complementary to blue overall. There has been proposed a method for improving the entire display device from being colored yellow when the display device is viewed obliquely (see, for example, Patent Document 3).

  Further, the thickness direction retardation values Rth (R), Rth (G), and Rth (B) of the red, green, and blue pixels of the color filter are matched with the wavelength dispersion of the liquid crystal material or retardation film to obtain Rth (R). > Rth (G)> Rth (B) or Rth (R) <Rth (G) <Rth (B) has been proposed to improve oblique visibility (see, for example, Patent Document 6). .

  However, the thickness direction retardation value of the color filter varies greatly depending on the type of pigment used, and the present inventors have previously made the pigment finer, dispersible, or matrix resin (for example, acrylic resin or It has been found that the degree of retardation value in the thickness direction is increased by a cardo resin, etc., and the above-mentioned problem cannot be solved by the method of containing the polymer or birefringence reducing particles described above. It was.

  In particular, for color filters based on transparent resins represented by acrylic resins with good dispersibility of organic pigments for high-contrast liquid crystal display devices, extremely high contrast values (2,000 or more) recently required for large TVs and the like It is difficult to simultaneously solve the adverse effects such as image sticking generated in the liquid crystal display device having a structure in which the colored layer is in contact with the liquid crystal.

  In addition, in the prior art, a color filter having a small birefringence index is simply an excellent color filter, and although a means for improving oblique visibility has been studied, a high-contrast liquid crystal display device can be used. In consideration of the wavelength dispersion of the birefringence of the liquid crystal material and the optical compensation layer, there has been little study on means for adjusting the thickness direction retardation of each color of the color filter to an optimum value up to a level at which there is no problem with black display. It was.

  As described above, in the conventional technique, when a COA structure is used, a display defect is solved by simply selecting a coloring layer material without providing an overcoat layer, and at the same time, a liquid crystal material and an optical device are used as a high-contrast liquid crystal display device. By taking into account the wavelength dispersion of the birefringence of the compensation layer, the thickness direction retardation of each color of the color filter is adjusted to an optimal value to improve oblique visibility, that is, to solve the problem of coloring in black display I couldn't do it.

JP 2004-117537 A JP 2006-113099 A JP 2000-136253 A JP 2000-187114 A JP 2001-242460 A JP 2007-212603 A JP 2007-328324 A JP 2007-225862 A

Ishibe et al., The Society for Information Display Digest, 1094. (2000).

  The present invention has been made to solve the above problems, and in a liquid crystal display device having a COA structure, even if a slit is provided in the pixel electrode, the electrical properties of the colored pixels are poor in liquid crystal alignment. Therefore, it does not adversely affect the switching threshold deviation, and therefore, without providing a protective layer made of transparent resin, it has high contrast, oblique visibility and front visibility, and burn-in that the colored layer gives to the liquid crystal. It is an object of the present invention to provide a liquid crystal display device including an improved COA substrate.

  In order to solve the above problems, one embodiment of the present invention includes a transparent substrate and an array substrate including an active element for driving liquid crystal, a pixel electrode, and a color filter, and a liquid crystal is interposed between the transparent substrate and the array substrate. In the sandwiched liquid crystal display device, the color filter has at least a red pixel, a green pixel, and a blue pixel, and a relative dielectric constant of a colored layer constituting these pixels is in a range of 3.0 to 4.2. And the thickness direction retardation value Rth (R) of the red pixel, the thickness direction retardation value Rth (G) of the green pixel, and the thickness direction retardation value Rth (B) of the blue pixel are expressed by the following formula (1) And a liquid crystal display device satisfying both of the expressions (2).

Rth (G) ≧ 0 (1)
Rth (B) <Rth (G)> Rth (R) (2)
(Where Rth (R) is a thickness direction retardation value for light having a wavelength of 610 nm passing through a red pixel, Rth (G) is a thickness direction retardation value for light having a wavelength of 545 nm passing through a green pixel, and Rth (B). Represents the thickness direction retardation value for light having a wavelength of 450 nm that passes through the blue pixel, and Rth (R), Rth (G), and Rth (B) are refractive in the thickness direction from the average in-plane refractive index of each pixel. (This is a value obtained by multiplying the value by the ratio and the pixel thickness (nm).)
In the liquid crystal display device configured as described above, the thickness direction retardation value Rth (G) of the green pixel can be set to a value in the range of 0 nm to 100 nm. Further, the colored layer constituting the green pixel may be formed by dispersing a green pigment containing a halogenated zinc phthalocyanine pigment.

  Furthermore, the liquid crystal display device may be configured such that the pixel electrode is provided directly on the colored layer, and the colored layer is exposed from the opening of the pixel electrode. Further, at least one color of the colored layer may contain a retardation adjusting agent. In this case, as the retardation adjusting agent, a compound having at least one planar structure group having at least one crosslinkable group can be used.

  In addition, the dielectric loss tangent of the colored layer may be 0.03 or less in a liquid crystal driving frequency range of 10 Hz to 500 Hz.

  Chromaticity (u (⊥), v (⊥)) when viewed from the vertical direction when the liquid crystal display device displays black, and when viewed from an orientation inclined by θ ° from the normal direction of the display surface The chromaticity difference Δuv represented by the following formula (4) of the chromaticity (u (θ), v (θ)) is 0.02 or less in the range of 0 <θ ≦ 60. .

Δuv = [{u (⊥) −u (θ)} 2+ {v (⊥) −v (θ)} 2] 1/2 (4)
Further, as the transparent substrate, a transparent substrate having an opening on the surface in contact with the liquid crystal and provided with a transparent conductive film for regulating the alignment of the liquid crystal is used. A liquid crystal having a tropic alignment can be used.

  Alternatively, a homogeneous alignment liquid crystal can be used in the absence of an electric field as the liquid crystal.

  According to one embodiment of the present invention, when applied to a VA mode or IPS mode liquid crystal display device, a protective layer (overcoat layer) made of a transparent resin is not provided, so that there is no liquid crystal alignment failure and no switching threshold shift. There is provided a liquid crystal display device including a COA substrate that does not adversely affect display performance, has an extremely high contrast, and has improved both oblique visibility, front visibility, and image sticking.

It is sectional drawing which shows the liquid crystal display device of a MVA system which has a colored pixel lamination | stacking spacer. It is sectional drawing which shows the MVA-type liquid crystal display device which has the conventional colored pixel lamination | stacking spacer. It is a flowchart figure which shows the process which manufactures the liquid crystal display device which concerns on one Embodiment of this invention. It is sectional drawing which shows the liquid crystal display device of the MVA system using the conventional protrusion. It is sectional drawing which shows the liquid crystal display device of a MVA system. It is a figure which shows the dielectric loss tangent of the colored layer which comprises the conventional color w-filter.

  Hereinafter, liquid crystal display devices according to various embodiments of the present invention will be described in detail with reference to the drawings.

  A liquid crystal display device according to an embodiment of the present invention includes a transparent substrate, an array substrate including an active element for driving liquid crystal, a pixel electrode, and a color filter, a so-called COA substrate, and the space between the transparent substrate and the array substrate. A liquid crystal display device having a liquid crystal sandwiched between them, wherein a colored layer constituting a color filter has a predetermined relative dielectric constant, and a thickness direction retardation value of each colored pixel has a predetermined relationship. To do.

  The COA substrate used in this liquid crystal display device includes a colored layer that constitutes colored pixels of a plurality of colors. These multiple colors include combinations of red, green, and blue (RGB), yellow, magenta, and cyan (YMC). The COA substrate coloring layer described in detail below is particularly preferably applicable to red, green, and blue (RGB). In addition to these colored pixels, non-colored pixels made of a transparent resin may be used in combination to increase the transmittance.

  The COA substrate used in the liquid crystal display device according to an embodiment of the present invention has a red pixel thickness direction retardation value Rth (R), a green pixel thickness direction retardation value Rth (G), and a blue pixel thickness direction. The phase difference value Rth (B) satisfies both the following formulas (1) and (2).

Rth (G) ≧ 0 (1)
Rth (B) <Rth (G)> Rth (R) (2)
(Where Rth (R) is a thickness direction retardation value for light having a wavelength of 610 nm passing through a red pixel, Rth (G) is a thickness direction retardation value for light having a wavelength of 545 nm passing through a green pixel, and Rth (B). Represents the thickness direction retardation value for light having a wavelength of 450 nm that passes through the blue pixel, and Rth (R), Rth (G), and Rth (B) are refractive in the thickness direction from the average in-plane refractive index of each pixel. (This is a value obtained by multiplying the value by the ratio and the pixel thickness (nm).)
By using a COA substrate in which the thickness direction retardation value of each colored pixel satisfies both the above formulas (1) and (2), a liquid crystal display device having good oblique visibility can be obtained.

  The thickness direction retardation value of each colored pixel is obtained by irradiating continuous light including the wavelength of the transmitted light peak region in the visible region (for example, the light wavelength range of 380 nm to 780 nm) from the front and a plurality of inclined angles. It is obtained by measuring the three-dimensional refractive index using a phase difference measuring device such as

  For example, light of a wavelength of 610 nm is used for a red pixel, 545 nm for a green pixel, and 450 nm is used for a blue pixel, and phase difference measurement is performed using light from at least two directions of the front and an incident angle of 45 degrees, and Nx, Ny, and Nz 3 After obtaining the dimensional refractive index, the thickness direction retardation value (Rth) is calculated by the following equation (3).

Rth = {(Nx + Ny) / 2−Nz} × d (3)
(In the formula, Nx is the refractive index in the x direction in the plane of the colored pixel layer, Ny is the refractive index in the y direction in the plane of the colored pixel layer, and Nz is the thickness direction of the colored pixel layer. (Refractive index, which is a slow axis where Nx is Nx ≧ Ny. D is the thickness (nm) of the colored pixel layer.)
At this time, when the object to be measured is a colored layer of the COA substrate, the measurement is performed through a mask processed so as to transmit only the single colored pixel layers of R, G, and B. The retardation value of the layer can be obtained.

  Further, for example, when light having a wavelength of 610 nm is used as incident light, a phase difference value caused only by a red pixel, when 545 nm, a phase difference value caused only by a green pixel, and when 450 nm, a blue pixel It is possible to estimate an approximate value of a single colored pixel layer as a phase difference value caused by only each.

  When the object to be measured is a single colored pixel layer of R, G, or B (a configuration in which a coating film of a colored composition for forming a colored layer of a COA substrate is formed on a transparent substrate in a single color) The phase difference can be measured without using a mask.

  The thickness direction retardation value of a film such as a biaxial retardation film can be measured by the same method.

  When the color filter described above is used in a liquid crystal display device provided with an optical compensation layer provided on the inner side of a polarizing plate disposed on each of the outer surfaces of the liquid crystal cell, the oblique direction when viewed from the vertical direction of the display surface The difference in chromaticity when viewed from above can be set within a predetermined range. As a result, the dispersion of the polarization state of the light passing through the display area of each colored pixel of the colored layer of the COA substrate is reduced, and a liquid crystal display device with good visibility in the oblique direction and the front can be obtained.

  For example, the liquid crystal display device is displayed in black and the chromaticity (u, v) expressed in the CIE1960 color system is measured, and the chromaticity (u (⊥), v (⊥)) when viewed from the vertical direction. And the chromaticity difference Δuv represented by the following equation (4) of the chromaticity (u (θ), v (θ)) when viewed from an orientation inclined by θ ° from the normal direction of the display surface, It is preferable to be 0.02 or less in the range of <θ ≦ 60.

Δuv = [{u (⊥) −u (θ)} 2+ {v (⊥) −v (θ)} 2] 1/2 (4)
Next, the principle of the liquid crystal display device according to one embodiment of the present invention will be described.

  The optical compensation layer used in the above-described VA mode liquid crystal display device is generally a biaxial retardation film having a refractive index ellipsoid represented by nx ≧ ny> nz, or a polymerizable liquid crystal property. In most cases, the retardation film is formed by applying a non-polymerizable liquid crystal material, and when these films are used, the thickness direction retardation value Rth usually increases as the wavelength increases. It has chromatic dispersion (hereinafter referred to as Cauchy's dispersion formula) in which the value increases as the value increases or the wavelength decreases.

  In general, for VA mode liquid crystal display devices that have both wavelength birefringence and liquid crystal birefringence when viewed obliquely, the Rth wavelength dispersion of these films completely compensates for the wavelength dispersion of the liquid crystal. If not, a problem of deteriorating display characteristics viewed from an angle particularly during black display is caused. That is, when viewed from an oblique direction, the black display adversely affects the yellowish visibility.

  In addition, since the liquid crystal display device such as the IPS mode or the FFS mode, which is known as a wide viewing angle liquid crystal mode, is not affected by the viewing angle dependency of the liquid crystal, for example, a biaxial retardation film satisfying nx ≧ ny ≧ nz is used. In most cases, it is a combination of retardation films for the IPS mode, or a transparent protective film such as TAC having no optical compensation function (for example, Ishibe et al., SID Digest, 1994. ( 2000), Ishibe et al., Jpn. J. Appl. Phys., 41, 4553. (2002)).

  In general, for an IPS mode liquid crystal display device in which a thickness direction retardation does not occur, the positive thickness direction retardation of these films causes light leakage, and deteriorates the display characteristics viewed from an angle particularly during black display. It will cause problems. That is, when viewed from an oblique direction, the black display has an adverse effect on the yellowish visibility.

  On the other hand, it is usually desired that the absolute value of the birefringence of the colored layer of the COA substrate is 0.01 or less, that is, the thickness direction retardation value (Rth) is unlimited and is close to RRth = GRth = BRth = 0. However, the present inventors have found that the thickness direction retardation value (Rth) of each color pixel of red, green, and blue is determined by the type of pigment to be used, the fineness or dispersion of the pigment, or the matrix resin (for example, acrylic resin or cardo resin). ) Are different, and as an example, it has been found that red indicates positive or negative Rth, blue indicates positive Rth, and green indicates negative Rth.

  As a result, the visibility from the front (vertical direction) with respect to the display surface is good, but only a specific color leaks in the visibility observed from an oblique angle such as 45 degrees (hereinafter referred to as oblique visibility). Therefore, when viewed from an oblique direction during black display, coloring such as reddish, bluedish, or greenish is produced.

  More importantly, as the contrast of the colored layer of the COA substrate increases, that is, as the depolarization of the colored layer of the COA substrate decreases, the chromaticity when viewed from the front during black display is the crossed Nicols of the polarizing plate. It is a point that approaches the chromaticity of.

  The dichroism of the polarizing plate is also improved, and in recent years, a high-contrast polarizing plate has been used, but most of the hues in crossed Nicols are bluish. That is, since there is much light leakage from the polarizing plate at a wavelength around 400 nm, the hue when viewed from the front during black display is bluish.

  Therefore, it is necessary to select a combination that obtains the optimum oblique visibility in the combination of the optical members of the liquid crystal display device such as a liquid crystal, a polarizing plate, a retardation plate, and an alignment film. In order to minimize the color change at the time, it is necessary to make the chromaticity when viewed obliquely blue.

  As a result of diligent investigations on these, the present inventors have found that liquid crystal having good oblique visibility by satisfying the following formulas (1) and (2) for each color thickness direction retardation value Rth of the colored layer of the COA substrate. It has been found that a display device can be obtained.

Rth (G) ≧ 0 (1)
Rth (B) <Rth (G)> Rth (R) (2)
That is, by setting the thickness direction retardation value of the green pixel to 0 or more and the thickness direction retardation value of the blue and red pixels to a value smaller than the thickness direction retardation value of the green pixel, the COA substrate is colored when viewed from the front. The thickness direction retardation value of the layer has no effect, and when viewed obliquely, the light leakage in the blue region is greater than the light leakage in the green region, and the color difference from the front chromaticity is reduced by being bluish. I can do it.

  Thus, when combined with the wavelength dispersion of a component other than the colored layer of the COA substrate, for example, a TAC film, an optimum COA substrate other than Rth (R) = Rth (G)) = Rth (B) = 0 It has been found that there is a value for the thickness direction retardation of the colored layer.

  In order to obtain good front visibility, particularly a tightened color with low black luminance in black display, in the case where the colored display pixel is a COA substrate formed using a pigment-dispersed coloring composition, the primary color of the pigment. As for the particle size distribution of the particles, the particle size d50 corresponding to 50% of the total amount in the integrated curve of the number particle size distribution is preferably 40 nm or less, and more preferably d50 is 30 nm or less. This is because, when the particle diameter d50 of the primary particles of the pigment is within such a range, a liquid crystal display device having good visibility not only from the oblique direction but also from the front direction can be obtained.

  In addition, as a result of various studies on the relationship between the electrical properties of the colored layers used in the colored pixels constituting the COA substrate and the display defects in the VA liquid crystal display device, the present inventors have found that the VA liquid crystal display device It has been found that image sticking, liquid crystal alignment failure, and switching threshold shift are highly correlated with the relative dielectric constant of the colored layer. Through detailed examinations by the present inventors, it has been found that the problems of these liquid crystal display devices can be improved by making the dielectric constant of the colored layer smaller than 4.2. Similarly, in the IPS liquid crystal display device, it is extremely effective to improve the image quality by making the dielectric constant of the colored layer smaller than 4.2.

  In the case of a liquid crystal display device having a COA structure, the following explanation can be generally made based on the value of the dielectric loss tangent. As a result of the study by the present inventors, it has been understood that a colored layer having a large dielectric loss tangent, for example, a colored layer of 0.033 or more, or 0.04 or more, leads to liquid crystal burn-in or poor alignment. The dielectric loss tangent (tan δ) is the ratio of the current flowing through the parasitic resistance to the theoretical current. When the dielectric loss tangent is relatively small, a theoretical current flows, whereas when the dielectric loss tangent is relatively large, the current is consumed as heat.

  In the VA mode liquid crystal display device having the COA structure as shown in FIG. 5, since the colored layer provided on the COA substrate contacts the liquid crystal through the slit, the parasitic capacitance increases with the relative dielectric constant of the colored layer. In parallel, there is a phenomenon in which the charge retention state of the liquid crystal molecules becomes non-uniform due to the influence of electrical characteristics such as relative permittivity of members (liquid crystal, alignment film, etc.) in other cells.

  As described above, the non-uniform charge holding state causes a display defect such as a liquid crystal alignment failure or a burn-in due to a switching threshold shift. Therefore, the relative dielectric constant (or large dielectric loss tangent) of the colored layer constituting the colored pixels of the COA substrate is an important characteristic that determines the display characteristics of the VA liquid crystal display device.

  The relative permittivity and the dielectric loss tangent are values depending on the measurement frequency. However, since one frame for driving the liquid crystal is about 60 Hz to 240 Hz, the period (second), that is, the frequency is around 60 Hz, generally at a frequency of 10 to 500 Hz. It is appropriate to pay attention to the dielectric constant and dielectric loss tangent.

  Here, an example of the measurement result of the dielectric loss tangent of the colored layer used in the conventional color filter is shown in FIG. The dielectric loss tangent of each color layer constituting the conventional color filter is in the range of 10 Hz to 500 Hz, and shows a value of about 0.006 to 0.25 depending on the type of the color layer. In particular, many of the green colored layers have large dielectric loss tangents. In fact, at least in the green colored layer, liquid crystal alignment defects and switching threshold deviations are notable unless an overcoat layer is provided at the boundary with the liquid crystal sandwiching surface. It was easy to occur.

  In the VA liquid crystal display device having a COA-structured pixel electrode having slits, the present inventors have provided a liquid crystal alignment defect and a switching threshold shift without providing an overcoat layer at the boundary between the colored layer and the liquid crystal sandwiching surface. In order to provide a liquid crystal display device that can eliminate such problems and improve the display quality without causing interference with the thin film transistor, various studies have been made on improving the characteristic dielectric characteristics of the colored layer.

  In general, a liquid crystal, an alignment film, and the like are formed using a material having a relatively small dielectric loss tangent, and the value is generally about 0.005 to 0.02. Accordingly, it is considered that the value of the dielectric loss tangent of the colored layer constituting the colored pixel of the COA substrate used in the VA liquid crystal display device is preferably the same value as the liquid crystal and the alignment film.

  That is, in a multicolored liquid crystal display device with a COA structure, the dielectric loss tangent of the colored layer constituting the colored pixel provided on the COA substrate is about 0.03 or less, preferably 0.02 or less in the range of 10 Hz to 500 Hz. As a result, it has been found that deterioration in display quality such as pixel orientation failure and threshold shift can be effectively prevented without providing an overcoat layer on the pixel. The lower the dielectric loss tangent of the colored layer, the better. However, the lower limit is about 0.005 to 0.006 at present due to the characteristics of the material of the colored layer.

  Further, as a result of various studies, the present inventors have found that in the liquid crystal display device of the present invention, the relative dielectric constant of the colored layer must be 4.2 or less in the frequency range of 10 Hz to 500 Hz. The relative dielectric constant is an index of the amount of charge accumulated in the dielectric. If the value is extremely large in the colored layer, parasitic capacitance coupling occurs between the signal line and the pixel electrode, causing display defects such as RC delay and crosstalk. It becomes. Therefore, the relative dielectric constant of the colored layer of the COA substrate is required to be 4.2 or less at a frequency of 10 Hz to 500 Hz, and more preferably 4.0 or less. A lower relative dielectric constant is preferable, but even if a resin material with a low relative dielectric constant (2.5 is the lower limit) is assumed, 3.0 is almost the lower limit in relation to organic pigments, including reproducibility in characteristics. is there.

  Conventionally, as a method for realizing these characteristics, for example, in Patent Document 1 or 2 described above, the concentration of a pigment, which is a component having a high dielectric loss tangent, is reduced to a certain level, the purity of the pigment is improved, and the pigment itself It has been reported that the dielectric loss tangent of is reduced.

  However, since these methods limit the degree of freedom in selecting a pigment, it may be difficult in terms of labor, time, and cost to meet various color characteristic requirements. Therefore, as a result of intensive studies, the present inventors have formed a colored layer using a colored resin composition containing a resin having a dielectric loss tangent of 0.008 or less, whereby the dielectric loss tangent of the colored layer is 0.03. It has been found that the following can easily be suppressed. This broadens the range of pigment selections, making it easy to provide color filters with color characteristics that meet various required specifications, thereby speeding up development and reducing development and material costs. Is also connected.

  FIG. 1 is a cross-sectional view showing an example of the structure of an MVA-type COA structure liquid crystal display device to which the liquid crystal display device according to an embodiment of the present invention can be applied.

  As shown in FIG. 1, this liquid crystal display device has a configuration in which a counter substrate 1 and a COA substrate 2 are arranged to face each other with a liquid crystal layer 4 interposed therebetween. The counter substrate 1 has a configuration in which a common electrode 13 having a slit 14 is provided on a glass substrate 11, and the COA substrate 2 is a thin film transistor 3 on a glass substrate 21 and a colored layer (color color) composed of a plurality of colored pixels. The pixel electrode 24 having the filter 23 and the slit 26 is provided.

  Note that polarizing plates 12 and 22 are provided on the opposite side, that is, the outer side, of the opposing substrate 1 and the COA substrate 2, and the alignment films 15 and 27 are provided on the opposing surface, that is, the surface in contact with the liquid crystal layer 4. Is formed.

  The pixel electrode 24 is a transparent conductive film made of ITO (indium tin oxide), zinc oxide, tin oxide, gallium oxide or the like, and the slit 26 is formed by photoetching of the pixel electrode 24.

  In order to set a predetermined distance between the counter substrate 1 and the COA substrate 2, a photo spacer 28 including a stack of colored pixels is provided. The photo spacer 28 is configured by stacking a colored dot pattern on the colored layer 23. These colored dot patterns are formed at the same time as the formation of these three colored pixels, using the same material as that of the colored layer used to form the green, red, and blue pixels. Lamination is performed by forming one or two colors of the colored pattern used to form another colored layer on a predetermined colored layer, and the number of laminated layers may be appropriately selected according to the specifications of the photospacer.

  After the pixel electrode 24 is provided on the entire surface of the glass substrate 21 on which the photospacer 28 is formed, the slit 26 is formed by photoetching, but the pixel electrode 24 is also formed on the photospacer 28. In order to prevent an electrical short circuit with the substrate 1, the pixel electrode 24 on the photo spacer 28 needs to be removed when the slit 26 is formed.

  FIG. 2 is a cross-sectional view showing a conventional example of a MVA-type COA structure liquid crystal display device. The liquid crystal display device according to one embodiment of the present invention described above can also be applied to this structure.

  This liquid crystal display device has the same structure as the liquid crystal display device shown in FIG. 1 except that an insulating dot pattern 29 is formed on the portion of the pixel electrode 24 on the photospacer 28.

  In this case, the insulating dot pattern 29 is provided in order to prevent an electrical short circuit with the counter substrate 1, but the pixel electrode 24 on the photo spacer 28 is slit 26 as in the liquid crystal display device having the structure shown in FIG. Since it becomes unnecessary by removing it by photoetching at the same time as the formation of, an inexpensive COA substrate and liquid crystal display device can be obtained.

  A method for obtaining a COA substrate used in the liquid crystal display device according to the present embodiment will be described below. The COA substrate used in the present embodiment includes a plurality of color pixels on at least a transparent substrate, and the plurality of color pixels includes at least a colored layer. A plurality of colors include a combination of red, green and blue (RGB) and a combination of yellow, magenta and cyan (YMC). The COA substrate used in the liquid crystal display device of the present invention has red, green and blue (RGB). The present invention can be particularly preferably applied to a COA substrate having a colored layer (that is, an RGB system).

  The COA substrate used in this embodiment is used by being incorporated in a liquid crystal display device with the pixel formation surface facing the liquid crystal sandwiching surface side. An alignment film is formed on the pixels as necessary. In addition, since the COA substrate used in this embodiment does not affect the electric characteristics of the colored layer in the liquid crystal driving electric field, it is not necessary to provide an overcoat layer that covers the colored layer, which improves the yield and leads to cost reduction. . In addition, since the distance between the liquid crystal and the pixel becomes closer, the viewing angle is improved and a high-definition liquid crystal display device can be provided.

  As described above, the COA substrate used in the present embodiment does not need to be provided with an overcoat layer in order to supplement the electrical characteristics of the colored layer, but can be provided with a resin layer for the purpose of planarizing the array substrate. In this case, the thickness as in the conventional overcoat layer is not necessary.

  The transparent substrate of the COA substrate used in this embodiment preferably has a certain degree of transmittance with respect to visible light, and more preferably has a transmittance of 80% or more. Generally, it may be one used in a liquid crystal display device, and examples thereof include a plastic substrate such as PET and glass, but a glass substrate is usually used.

  The colored layer on the transparent substrate may be produced by any known method such as an inkjet method, a printing method, a photolithography method, or an etching method. However, considering high definition, controllability and reproducibility of spectral characteristics, etc., a colored resin composition in which a pigment is dispersed in a transparent resin together with a photoinitiator and a polymerizable monomer in a suitable solvent is formed on a transparent substrate. A photoresist method is preferred in which a coating film is formed on the coating film, and a process of forming a colored layer of one color by pattern exposure and development on the coating film is repeated for each color to produce a COA substrate.

  When the colored layer constituting the pixels included in the COA substrate used in the present embodiment is prepared by photolithography by preparing a colored resin composition, for example, the following method is used.

  First, a pigment as a colorant is dispersed in a suitable solvent together with a photoinitiator and a polymerizable monomer in a transparent resin. There are various methods such as mill base, three rolls, jet mill and the like, and there are no particular limitations.

  Specific examples of organic pigments that can be suitably used for forming the colored layer are shown below by color index numbers.

  Examples of red compositions for forming red pixels include C.I. I. Pigment Red 7, 9, 14, 41, 48: 1, 48: 2, 48: 3, 48: 4, 81: 1, 81: 2, 81: 3, 97, 122, 123, 146, 149, 168, 177, 178, 179, 180, 184, 185, 187, 192, 200, 202, 208, 210, 215, 216, 217, 220, 223, 224, 226, 227, 228, 240, 246, 254, 255, Red pigments such as H.264, 272, and 279 can be used. A yellow pigment and an orange pigment can be used in combination with the red composition.

  When the red pixel contains one or more of diketopyrrolopyrrole red pigments and anthraquinone red pigments among these pigments, it is preferable because any Rth can be easily obtained. Because these red pigments are excellent in transparency, and by devising the method of synthesizing the pigment and the refinement of the pigment, it is possible to move the Rth in the negative to positive direction with high contrast. This is because the absolute value can be controlled to some extent.

It can be said that the value of Rth almost holds the additive rule depending on the blending ratio of the pigment used. The amount of the pigment used is 0 to 100% by weight of the diketopyrrolopyrrole red pigment, preferably 10 to 90% by weight, and 0 to 66% by weight of the anthraquinone red pigment, preferably 5 based on the total weight of the pigment. -70 wt% is preferable from the viewpoint of the hue, brightness, film thickness, contrast, etc. of the pixel. Especially when focusing on the contrast, 25-75 wt% of diketopyrrolopyrrole red pigment, anthraquinone red More preferably, the pigment is 30 to 60% by weight.

  The red pixel can contain a yellow pigment or an orange pigment for the purpose of adjusting the hue, but it is preferable to use an azo metal complex-based yellow pigment from the viewpoint of high contrast. The amount used is preferably 5 to 25% by weight based on the total weight of the pigment, and if it is less than 5% by weight, it becomes difficult to adjust the hue such as sufficient brightness, and the amount exceeds 30% by weight. In this case, since the hue is shifted too yellow, the color reproducibility is deteriorated.

  Examples of yellow pigments include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 20, 24, 31, 32, 34, 35, 35: 1, 36, 36: 1, 37, 37: 1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 86, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 125, 126, 127, 128, 129, 137, 138, 139, 144, 146, 147, 148, 150, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 1 73, 174, 175, 176, 177, 179, 180, 181, 182, 185, 187, 188, 193, 194, 199, 213, 214 and the like.

  Examples of orange pigments include C.I. I. Pigment Orange 36, 43, 51, 55, 59, 61, 71, 73 and the like.

  In the above, examples of the diketopyrrolopyrrole red pigment include C.I. I. Pigment Red 254, an anthraquinone red pigment, "C.I. I. Pigment Red 177, an azo metal complex yellow pigment such as C.I. I. Pigment Yellow 150 is preferable in terms of excellent light resistance, heat resistance, transparency, coloring power, and the like.

  Examples of green compositions for forming green filter segments include C.I. I. Pigment Green 7, 10, 36, 37, 58, etc., preferably C.I. I. Pigment Green 58 can be used. A yellow pigment similar to the red composition can be used in combination with the green composition.

  It is preferable that the green pixel contains at least one of a halogenated metal phthalocyanine green pigment, an azo yellow pigment, and a quinophthalone yellow pigment among these pigments because it becomes easy to obtain an arbitrary Rth. . This is because the halogenated metal phthalocyanine green pigment can control Rth (G) to some extent by selecting the central metal. For example, when the central metal is copper, Rth has a negative value. However, when the central metal is zinc, the value of Rth can be increased from 0 to a positive value than when copper is the central metal. In addition, azo yellow pigments can obtain positive Rth (G) regardless of the refining treatment, and quinophthalone yellow pigments can obtain negative Rth (G) regardless of the refining treatment. This is because desired Rth can be easily obtained.

Also for the green pixel, it can be said that the Rth value almost satisfies the additive rule based on the blending ratio of the pigment used. The amount of the pigment used is 30 to 90% by weight of the halogenated metal phthalocyanine green pigment, 0 to 60% by weight of the azo yellow pigment and / or quinophthalone yellow pigment, preferably 5 to 5%, based on the total weight of the pigment. 60% by weight is preferable from the viewpoint of the hue, brightness, and film thickness of the pixel. More preferably, the halogenated metal phthalocyanine green pigment is 50 to 85% by weight, the azo yellow pigment is 5 to 45% by weight, and the quinophthalone yellow pigment is 5 to 45% by weight. Particularly preferred are zinc halide phthalocyanine pigments. Different types of central metal pigments such as a halogenated copper phthalocyanine pigment and an aluminum halide phthalocyanine pigment may be used in combination with the halogenated zinc phthalocyanine pigment.

  Examples of the halogenated metal phthalocyanine green pigment include C.I. I. Pigment Green 7, 36, 58, and azo yellow pigments include C.I. I. Pigment Yellow 150 and quinophthalone yellow pigments include C.I. I. Pigment Yellow 138 is preferable in terms of excellent light resistance, heat resistance, transparency, coloring power, and the like.

  Blue compositions for forming blue filter segments include, for example, C.I. I. Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 22, 60, 64, 80, etc., preferably C.I. I. Pigment Blue 15: 6 can be used.

  The blue composition includes C.I. I. Pigment Violet 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, 50 and the like, preferably C.I. I. Pigment Violet 23 can be used in combination.

  The amount used is 40 to 100% by weight of the metal phthalocyanine blue pigment and 0 to 50% by weight, preferably 1 to 50% by weight of the dioxazine violet pigment based on the total weight of the pigment. It is preferable from the viewpoints of hue, brightness, film thickness, and the like, and more preferably 50 to 98% by weight of the metal phthalocyanine blue pigment and 2 to 25% by weight of the dioxazine violet pigment.

  In the above, examples of the metal phthalocyanine blue pigment include C.I. I. Pigment Blue 15: 6, and dioxazine-based purple pigments include C.I. I. Pigment Violet 23 is preferable in terms of excellent light resistance, heat resistance, transparency, coloring power, and the like.

  In combination with the organic pigment, an inorganic pigment may be used in combination in order to ensure good coatability, sensitivity, developability and the like while balancing saturation and lightness. Inorganic pigments include yellow lead, zinc yellow, red bean (red iron oxide (III)), cadmium red, ultramarine, bitumen, chromium oxide green, cobalt green and other metal oxide powders, metal sulfide powders, metal powders, etc. Can be mentioned. Furthermore, for color matching, a dye can be contained within a range that does not lower the heat resistance.

  The pigment contained in the colored pixel is preferably miniaturized and preferably has a small average primary particle size in order to achieve high brightness and high contrast of the colored layer of the COA substrate. The average primary particle diameter of the pigment can be calculated by taking the pigment with a transmission electron microscope and analyzing the image of the photograph.

  The average primary particle diameter of the pigment is preferably 40 nm or less, more preferably 30 nm or less, and still more preferably 20 nm or less. Moreover, it is preferable that an average primary particle diameter is 5 nm or more. When the average primary particle diameter of the pigment is larger than the upper limit value, the visibility of the liquid crystal display device during black display is poor. Moreover, when smaller than a lower limit, pigment dispersion | distribution becomes difficult, it becomes difficult to maintain stability as a coloring composition and to ensure fluidity | liquidity.

  As a result, the luminance and color characteristics of the colored layer of the COA substrate are deteriorated. In particular, an organic pigment having an average primary particle diameter exceeding 40 μm adversely affects front visibility.

In addition, each color pixel formed on the transparent substrate is sandwiched between two polarizing plates, a backlight is applied from one polarizing plate side, and the light transmitted through the other polarizing plate is measured with a luminance meter. The contrast C calculated from the ratio of the light luminance (Lp) in the parallel state and the light luminance (Lc) in the orthogonal state is calculated from C = Lp / Lc, CS is only the substrate without colored pixels, and CR is When red pixel, CG represents green pixel, and CB represents blue pixel contrast, CR / CS> 0.45, CG / CS> 0.45, and CB / CS> 0.45,
As shown in Table 6, the front visibility at the time of black display of the liquid crystal display device is excellent. That is, it is possible to reproduce a tight black display with little light leakage.

  When CR / CS> 0.45, CG / CS> 0.45, and CB / CS> 0.45 are not satisfied, that is, CR / CS ≦ 0.45 or CG / CS ≦ 0. In the case of 45 or CB / CS ≦ 0.45, light leakage during black display increases and a liquid crystal display device with excellent front visibility cannot be obtained.

  Furthermore, by reducing the retardation difference for each color, the liquid crystal display device is excellent in both oblique visibility and front visibility.

  Even if CR / CS> 0.45, CG / CS> 0.45, and CB / CS> 0.45 are satisfied, if the retardation difference for each color is large, the oblique visibility is insufficient. Sometimes.

  Means for controlling the average primary particle diameter and thickness direction retardation of the pigment include a method in which the pigment is mechanically pulverized to control the primary particle diameter and particle shape (called a grinding method), and a solution in a good solvent. A method in which a pigment having a desired primary particle size and particle shape is deposited by introducing it into a poor solvent (referred to as a precipitation method), and a method for producing a pigment having a desired primary particle size and particle shape at the time of synthesis (referred to as a synthetic precipitation method) ) Etc. Depending on the synthesis method and chemical properties of the pigment to be used, an appropriate method can be selected for each pigment.

  Each method will be described below, and any of the methods for controlling the primary particle diameter and particle shape of the pigment contained in the colored pixel layer constituting the colored layer of the COA substrate according to one embodiment of the present invention is used. May be.

  In the grinding method, the pigment is mechanically kneaded using a ball mill, sand mill or kneader together with a grinding agent such as water-soluble inorganic salt such as salt and a water-soluble organic solvent that does not dissolve it. This is a method of obtaining a pigment having a desired primary particle size and particle shape by washing and removing the inorganic salt and the organic solvent, followed by drying.

  However, since the pigment may crystallize by the salt milling treatment, a method of preventing crystal growth by adding a solid resin or a pigment dispersant that is at least partially dissolved in the organic solvent during the treatment is effective.

  As for the ratio of the pigment to the inorganic salt, if the ratio of the inorganic salt is increased, the efficiency of refining the pigment is improved, but the productivity is lowered because the amount of pigment processed is reduced. In general, 1 to 30 parts by weight, preferably 2 to 20 parts by weight of the inorganic salt is used per 1 part by weight of the pigment. The water-soluble organic solvent is added so that the pigment and the inorganic salt are uniformly solidified. Although depending on the blending ratio of the pigment and the inorganic salt, the water-soluble organic solvent is usually added in an amount of 0.1% by weight with respect to 1 part by weight of the pigment. Used in an amount of 5 to 30 parts by weight.

  More specifically, regarding the grinding method, a small amount of a water-soluble organic solvent is added as a wetting agent to a mixture of a pigment and a water-soluble inorganic salt, and after kneading with a kneader or the like, the mixture is poured into water to achieve high speed. Stir with a mixer or the like to form a slurry. Next, this slurry is filtered, washed with water, and dried to obtain a pigment having a desired primary particle size and particle shape.

  The precipitation method is a method in which a pigment is dissolved in an appropriate good solvent and then mixed with a poor solvent to precipitate a pigment having a desired primary particle size and particle shape. The type and amount of the solvent, the precipitation temperature, the precipitation The primary particle size and particle shape can be controlled by the speed or the like.

  In general, pigments are difficult to dissolve in solvents, so the solvents that can be used are limited. For example, strongly acidic solvents such as concentrated sulfuric acid, polyphosphoric acid and chlorosulfonic acid, or basic substances such as dimethylformamide solution of liquid ammonia and sodium methylate Solvents are known.

  As a typical example of the precipitation method, there is an acid pasting method in which a solution in which a pigment is dissolved in an acidic solvent is poured into another solvent and reprecipitated to obtain fine particles. Industrially, a method of injecting a sulfuric acid solution into water is generally used from the viewpoint of cost. The concentration of sulfuric acid to be used is not particularly limited, but is preferably 95 to 100% by weight. The amount of sulfuric acid used with respect to the pigment is not particularly limited. However, if the amount is too small, the solution viscosity is high and handling becomes poor. On the other hand, if the amount is too large, the processing efficiency of the pigment decreases. Is preferably used.

  The pigment need not be completely dissolved. The temperature at the time of dissolution is preferably from 0 to 50 ° C. Below this temperature, sulfuric acid may freeze and the solubility will be low. If the temperature is too high, side reactions tend to occur.

  The temperature of the water to be injected is preferably 1 to 60 ° C. When the injection is started at a temperature higher than this temperature, boiling occurs due to the heat of dissolution of sulfuric acid, which is dangerous. It will freeze at temperatures below this. The injection time is preferably 0.1 to 30 minutes with respect to 1 part of the pigment. As the time increases, the primary particle size tends to increase.

  The primary particle size and particle shape of the pigment can be controlled while considering the size adjustment of the pigment by selecting a method that combines a precipitation method such as the acid pasting method and a grinding method such as the salt milling method. Further, it is more preferable because the fluidity as a dispersion can be secured at this time.

  During salt milling or acid pasting, in order to prevent aggregation of pigments accompanying primary particle size and particle shape control, the following pigment derivatives, resin type pigment dispersants, surfactants and other dispersing aids may be used in combination. it can.

  Further, by controlling the primary particle size and particle shape in the form of coexistence of two or more pigments, even a pigment that is difficult to disperse alone can be finished as a stable dispersion.

  There is a leuco method as a special precipitation method. When vat dyes such as flavantron, perinone, perylene, and indanthrone are reduced with alkaline hydrosulfite, the quinone group becomes a hydroquinone sodium salt (leuco compound) and becomes water-soluble. A pigment having a small primary particle size insoluble in water can be precipitated by adding an appropriate oxidizing agent to the aqueous solution for oxidation.

  The synthetic precipitation method is a method in which a pigment having a desired primary particle size and particle shape is precipitated simultaneously with the synthesis of the pigment. However, when the produced fine pigment is taken out of the solvent, if the pigment particles are not aggregated into large secondary particles, filtration, which is a general separation method, becomes difficult. It is applied to azo pigments synthesized in water.

  Furthermore, as a means for controlling the primary particle size and particle shape of the pigment, the primary particle size of the pigment is reduced by dispersing the pigment for a long time with a high-speed sand mill or the like (so-called dry milling method in which the pigment is dry pulverized). It is also possible to disperse at the same time.

  In addition, a retardation adjusting agent can be added to the color filter coloring composition of one or more colors in the colored layer of the COA substrate according to this embodiment, particularly for the purpose of improving oblique visibility. The retardation adjusting agent is an additive capable of adjusting the phase difference in the thickness direction of the color filter.

  A compound that can be used as a retardation adjusting agent that is suitable for addition to a colored resin composition for forming a colored layer and that eliminates the need to provide an overcoat layer in a liquid crystal display device having a COA structure is 1000 or 3000. In order to ensure the above high contrast, it is desirable that the organic compound has good dispersibility. Further, a compound having a transmittance of preferably 80% or more, more preferably 95% or more and a dielectric loss tangent of 0.03 or less in the frequency range of 10 Hz to 500 Hz in the entire wavelength region of 400 to 700 nm in the visible light region. It is good to be. This compound includes a thermoplastic resin, a thermosetting resin, and a photosensitive resin. If necessary, the transparent resin can be used alone or in admixture of two or more monomers or oligomers that are precursors thereof that are cured by irradiation with radiation to produce a transparent resin.

  Specifically, particles in the form of particles such as inorganic substances can be used, but it is desirable to avoid them from the viewpoints of light scattering and depolarization. Moreover, when forming a colored layer of a plurality of colors on a transparent substrate or the like, a retardation adjusting agent may be added to all colors, but it is also possible to add only one or two colors.

  As a specific retardation adjusting agent, a melamine resin, a porphyrin compound, and a polymerizable liquid crystal compound, which are organic compounds having a planar structure group having one or more crosslinkable groups, one or more aromatic-containing monomers of 70 to One or more selected from acrylic resins containing 90 mol% can be selected. The retardation of the colored layer can be greatly increased by increasing the amount of the retardation adjusting agent that increases the retardation and the dispersion technique. The present inventors have confirmed a colored layer having a retardation of about 100 nm by devising the addition amount of the melamine resin and the like.

  Usually, it is considered that Rth of the entire film can be canceled by adding particles having a planar structure group having birefringence opposite to that of a pigment or other resin. However, simply adding particles having a planar structure group will cause the particles themselves to be randomly oriented, and the effect on Rth of the entire film will be small.

  Thus, as a result of intensive studies, the present inventors have found that the Rth of the entire film is greatly changed by providing at least one crosslinkable group to the planar structural group of the retardation adjusting agent, and a sufficient effect can be obtained. I found. Further, among the regulators having a planar structure group, when the planar structure group is aromatic and the acrylic resin contains 70 to 90 mol% of the monomer having the aromatic in the resin solid content, It has been found that sufficient effects can be obtained as a retardation adjusting agent.

  That is, for example, the retardation adjusting agent has a functional group that crosslinks in the photocuring process or the thermosetting process in the photolithographic process, so that the planar structural group does not rotate freely and is flat when shrinking during thermosetting. Since the structural group is more easily oriented and fixed in the same direction, the thickness direction retardation Rth can be increased (in the positive direction). That is, the function as a phase difference adjusting agent can be expressed.

  The planar structural group of the melamine compound, the porphyrin compound, and the polymerizable liquid crystal compound, which are organic compounds having a planar structural group having one or more crosslinkable groups, has at least one aromatic ring. In cyclic hydrocarbons, phenyl group, cumenyl group, mesityl group, tolyl group, xylyl group, benzyl group, phenethyl group, styryl group, cinnamyl group, trityl group, etc.In polycyclic hydrocarbons, pentarenyl group, indenyl group, naphthyl group A known compound having a group, biphenylene group, acenaphthylene group, fluorene group, phenanthryl group, anthracene group, triphenylene group, pyrene group, naphthacene group, pentaphen group, pentacene group, tetraphenylene group, trinaphthylene group, or the like can be used. . For heteromonocyclic compounds, pyrrolyl group, imidazolyl group, pyrazolyl group, pyridyl group, pyrazinyl group, triazine group, etc.For heteropolycyclic compounds, indolizinyl group, isoindolyl group, indolyl group, purinyl group, quinolyl group, isoquinolyl group, phthalazinyl Group, naphthyridinyl group, quinoxalinyl group, cinolinyl group, carbazolyl group, carbolinyl group, acridinyl group, porphyrin group, and the like, which are exemplified by those having substituents such as hydrocarbon groups and halogen groups. May be.

As the at least one crosslinkable group attached to the planar structure group, an unsaturated polymerizable group (A, B, C, D, E, F) represented by the following formula or a functional group (I, J, K, L, M, N, O) or a thermally polymerizable group (G, H, P, Q, R, S, T, U) is preferable, and an epoxy group (G, H) is more preferably used. , P to U are most preferably used.

Further, the unsaturated polymerizable group is more preferably an ethylenically unsaturated polymerizable group (A, B, C, D), and —CH ₂ NHCOCH═CH ₂ , —CH ₂ NHCO (CH ₂ ). _{7CH = CH (CH 2) 7} CH 3 -OCO (C 6 H 4) O (CH 2) such as 6 CH = CH ₂ is also preferably used.

  These crosslinkable groups are glycidyl (meth) acrylate, 2- (meth) acryloyloxyisocyanate, tolylene-2, 4-, when the planar structural group has at least one reactive functional group such as a hydroxyl group. It can be easily obtained by reacting a functional group that reacts with the reactive functional group such as diisocyanate and a compound having an ethylenically unsaturated group by a known method.

  As a result of intensive studies, the inventors have found that the planar structure group has at least one crosslinkable group, thereby improving the crosslink density of the film and facilitating charge transfer between the planar structure groups. It has been found that the characteristics are improved.

Examples of the thermosetting resin include compounds having the structural formula (II) shown below and multimers thereof as melamine compounds.

(Wherein R ^{1 to} R ⁶ each represent a hydrogen atom or CH ₂ OR (R represents a hydrogen atom or an alkyl group, and R ^{1 to} R ⁶ may be the same or different). R ^{1 to} R ⁶ may be the same or different.) Two or more homopolymers or copolymers may be used in combination, or the above melamine compound and the compound containing an isocyanate group are reacted. What is formed may be used.

In addition to the above, compounds having a 1,3,5-triazine ring, for example, those described in JP-A No. 2001-166144 can be used. Further, compounds represented by the structural formula (III) shown below are also preferably used.

(R ⁷ to R ¹⁴ are each independently a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group, and particularly preferably a hydrogen atom.)
Alternatively, a compound having a porphyrin skeleton represented by the following general formula (IV) can be preferably used. n is an integer of 1 to 20, and 2 is preferably used.

In the formula, each of R ^{15 to} R ²² is independently a hydrogen atom, a halogen atom, an alkoxy group, an alkylthio group, a substituted or unsubstituted phenoxy group, a substituted or unsubstituted naphthoxy group, a substituted or unsubstituted phenylthio group, or a substituted group Alternatively, it represents an unsubstituted naphthylthio group.
Specific examples of the porphyrin compound represented by the general formula (IV) used in the present invention are described below. Examples of the halogen atom in R ^{15 to} R ²² include fluorine, chlorine, bromine and iodine. The alkoxy group and thioalkyl group are not particularly limited, but the alkyl group in the substituent is preferably a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, and having 1 to 8 carbon atoms. A linear, branched or cyclic alkyl group is particularly preferred. Z represents —CH ₂ — or —N—.

  Specific examples of the alkyl group in the alkoxy group and thioalkyl group include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, t-butyl group. Group, n-pentyl group, iso-pentyl group, 2-methylbutyl group, 1-methylbutyl group, neo-pentyl group, 1,2-dimethylpropyl group, 1,1-dimethylpropyl group, cyclopentyl group, n-hexyl group 4-methylpentyl group, 3-methylpentyl group, 2-methylpentyl group, 1-methylpentyl group, 3,3-dimethylbutyl group, 2,3-dimethylbutyl group, 1,3-dimethylbutyl group, 2 , 2-dimethylbutyl group, 1,2-dimethylbutyl group, 1,1-dimethylbutyl group, 3-ethylbutyl group, 2-ethylbutyl group, 1-ethyl Tyl group, 1,2,2-trimethylbutyl group, 1,1,2-trimethylbutyl group, 1-ethyl-2-methylpropyl group, cyclohexyl group, n-heptyl group, 2-methylhexyl group, 3-methyl Hexyl group, 4-methylhexyl group, 5-methylhexyl group, 2,4-dimethylpentyl group, n-octyl group, 2-ethylhexyl group, 2,5-dimethylhexyl group, 2,5,5-trimethylpentyl group 2,4-dimethylhexyl group, 2,2,4-trimethylpentyl group, n-octyl group, 3,5,5-trimethylhexyl group, n-nonyl group, n-decyl group, 4-ethyloctyl group, 4-ethyl-4,5-dimethylhexyl group, n-undecyl group, n-dodecyl group, 1,3,5,7-tetraethyloctyl group, 4-butyloctyl group, 6,6-di- Tyloctyl group, n-tridecyl group, 6-methyl-4-butyloctyl group, n-tetradecyl group, n-pentadecyl group, 3,5-dimethylheptyl group, 2,6-dimethylheptyl group, 2,4-dimethylheptyl Group, 2,2,5,5-tetramethylhexyl group, 1-cyclopentyl-2,2-dimethylpropyl group, 1-cyclohexyl-2,2-dimethylpropyl group and the like.

  Specific examples of the substituted or unsubstituted phenoxy group include phenoxy group, 2-methylphenoxy group, 3-methylphenoxy group, 4-methylphenoxy group, 2-ethylphenoxy group, 3-ethylphenoxy group, 4-ethyl. Examples include phenoxy group, 2,4-dimethylphenoxy group, 3,4-dimethylphenoxy group, 4-t-butylphenoxy group, 4-aminophenoxy group, 4-dimethylaminophenoxy group, 4-diethylaminophenoxy group and the like.

  Specific examples of the substituted or unsubstituted naphthoxy group include 1-naphthoxy group, 2-naphthoxy group, nitronaphthoxy group, cyanonaphthoxy group, hydroxynaphthoxy group, methylnaphthoxy group, trifluoromethylnaphthoxy group and the like. .

  Specific examples of the substituted or unsubstituted phenylthio group include a phenylthio group, a 2-methylphenylthio group, a 3-methylphenylthio group, a 4-methylphenylthio group, a 2-ethylphenylthio group, and a 3-ethylphenylthio group. Group, 4-ethylphenylthio group, 2,4-dimethylphenylthio group, 3,4-dimethylphenylthio group, 4-t-butylphenylthio group, 4-aminophenylthio group, 4-dimethylaminophenylthio group , 4-diethylaminophenylthio group and the like.

  Specific examples of the substituted or unsubstituted naphthylthio group include 1-naphthylthio group, 2-naphthylthio group, nitronaphthylthio group, cyanonaphthylthio group, hydroxynaphthylthio group, methylnaphthylthio group, trifluoromethylnaphthylthio group. Etc.

  X may be a combination of two or more compounds (for example, a compound having a 1,3,5-triazine ring and a compound having a porphyrin skeleton).

Examples of the plane-containing structural group epoxy compound include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol AD type epoxy compounds, hydrogenated bisphenol A type epoxy compounds and the like; for example, phenol novolak type Epoxy compounds, novolak-type epoxy compounds such as cresol novolak-type epoxy compounds; for example, glycidylamines such as tetraglycidyldiaminodiphenylmethane, triglycidyl-p-aminophenol, triglycidyl-m-aminophenol, tetraglycidyl-m-xylenediamine Epoxy compounds; for example, glycidyl ester epoxy such as diglycidyl phthalate, diglycidyl hexahydrophthalate, diglycidyl tetrahydrophthalate Compound; For example, complex epoxy compounds such as triglycidyl isocyanurate and glycidyl glycidoxy alkhydantoin can be exemplified. An example is shown in the following formula (V).

As the polymerizable liquid crystal compound, a rod-like liquid crystal molecule or a discotic liquid crystal molecule is preferable, and a discotic liquid crystal molecule is particularly preferable. As the rod-like liquid crystalline molecules, those described in JP-A-2006-16599 are preferably used. For example, azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoates, cyclohexanecarboxylic acid Phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are also used. As the discotic liquid crystalline molecules, for example, those described in JP-A-8-27284 can be used. An example is shown below.

  In the above formula, Y represents a divalent linking group selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, —CO—, —NH—, —O—, —S—, and combinations thereof, and Most preferably, the group is a combination of at least two divalent groups. The alkylene group preferably has 1 to 12 carbon atoms, the alkenylene group preferably has 2 to 12 carbon atoms, and the arylene group preferably has 6 to 10 carbon atoms. . The alkylene group, alkenylene group and arylene group may have a substituent (for example, an alkyl group, a halogen atom, a cyano, an alkoxy group, an acyloxy group).

In the above formula, R is an unsaturated polymerizable group (A, B, C, D, E, F) or a functional group (I, J, K, L, M, N, O) represented by the formula (I). ) Or a thermally polymerizable group (G, H, P, Q, R, S, T, U), or an alkyl group, an alkenyl group substituted with the crosslinkable group, An aryl group or a heterocyclic group. The unsaturated polymerizable group is more preferably an ethylenically unsaturated polymerizable group (A, B, C, D), and —CH ₂ NHCOCH═CH ₂ , —CH ₂ NHCO (CH ₂ ) ₇ CH ═CH (CH ₂ ) ₇ CH ₃ , —OCO (C ₆ H ₄ ) O (CH ₂ ) ₆ CH═CH _{2 and the} like are also preferably used.

  As an example of the compound containing an isocyanate group used for the above reaction, various known aromatic, aliphatic or alicyclic isocyanates can be used.

  For example, 1,5-naphthylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 4,4′-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3- Aromatic polyisocyanates such as phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, m-tetramethylxylylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethyl Aliphatic polyisocyanates such as hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, methylcyclohexane diisocyanate, etc. Examples thereof include alicyclic polyisocyanate and dimer isocyanate obtained by converting a carboxyl group of dimer acid into an isocyanate group.

  Moreover, when giving photosensitivity to this thermosetting resin, the compound containing an isocyanate group and a double bond group can be used suitably, 2-Athacryloyloxyethyl isocyanate, 2-methacryloyl Examples thereof include oxyethyl isocyanate, 1,1- (bisacryloyloxymethyl) ethyl isocyanate, and the like.

  Examples of acid anhydrides used in the above reaction include malonic acid anhydride, succinic acid anhydride, maleic acid anhydride, itaconic acid anhydride, phthalic acid anhydride, hexahydrophthalic acid anhydride, tetrahydrophthalic acid anhydride And methyltetrahydrophthalic anhydride.

In the thermosetting resin, the acid value is required to be 3 to 60 mgKOH / g in terms of solid content, and more preferably 20 to 50 mgKOH / g. Therefore, the addition reaction of the acid anhydride is quantitatively reacted so that the acid value falls within this range. If the acid value of the thermosetting resin is less than 3 mgKOH / g, there is a risk of developing failure in alkali development. If the acid value is greater than 60 mgKOH / g, the surface of the exposed part is eroded by the developer in alkali development. In addition, problems such as deterioration of long-term storage stability of the photosensitive resin composition are likely to occur.
The thermosetting resin described above can be prepared by any of the following methods.

(1) A method in which a melamine compound and a compound containing an isocyanate group are mixed and reacted under heating,
(2) A method in which a melamine compound and a compound containing an isocyanate group are mixed and reacted under heating, and then an acid anhydride is further mixed under heating to react.

  (3) A method in which a melamine compound and an acid anhydride are mixed and reacted under heating.

  Moreover, you may include the process of distilling off a low boiling alcohol compound using an evaporator etc. as a pretreatment, and the process of carrying out solvent substitution with the solvent suitable for the photosensitive resin composition.

  In general, thermosetting resins such as melamine compounds have high thermal reactivity and generally poor long-term storage stability, and thus it has been difficult to use them in a large amount in a photosensitive resin composition. However, in the above-mentioned thermosetting resin, some of the thermoreactive groups present in the melamine skeleton are used for the reaction with an isocyanate group-containing compound or acid anhydride. Is appropriately reduced, and the effect of improving the long-term storage stability of the photosensitive resin composition can be obtained. Further, as a result of the reaction with the isocyanate group-containing compound or acid anhydride, the polymer chain of the melamine resin becomes longer and the free movement of the melamine resin skeleton is constrained, so that the storage stability is improved. is there.

  The reaction with the isocyanate group-containing compound or acid anhydride makes it possible to impart alkali developability and / or photosensitivity necessary for the alkali development type photosensitive resin composition to the melamine resin. By providing alkali developability and / or photosensitivity in this way, adhesion with the substrate is improved, and a photosensitive resin composition having a good process margin that does not cause problems during the development process is realized. Can do.

Furthermore, by including the thermosetting resin in the photosensitive resin composition, not only can the cured coating film be provided with sufficient heat resistance and hardness, but also solvent resistance and alkali resistance functions. can do.

  In addition, by containing an appropriate amount of the thermosetting resin, elution of ionic impurities contained in pigments and other fine particles and / or contained in the manufacturing process can be reduced, and electrical characteristics can be improved. It becomes possible to do. That is, when the colored layer is baked and cured, the thermosetting resin reacts in the photosensitive resin composition, and the pigment and other fine particles are confined in the polymer network to suppress the elution of ionic impurities. It becomes possible. Further, by adding an appropriate amount of thermosetting resin, the aromatic ring of the thermosetting resin functions electronically, and the electrical characteristics of the cured film can be adjusted. As a result, it is possible to provide a liquid crystal display device having excellent electrical characteristics that is free from burn-in and color shift even when displayed for a long time.

As an acrylic resin containing 70 to 90 mol% of one or more aromatic-containing monomers used in this embodiment, various acrylic esters and methacrylic esters such as melamine (meth) acrylate and benzyl (meth) acrylate, styrene, And an aromatic-containing monomer represented by the following general formula (XII), (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, (iso) propyl (meth) acrylate, (iso) butyl (meth) acrylate , (Iso) pentyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, cyclohexyl (meth) acrylate, glycidyl (meth) acrylate, isobornyl (meth) acrylate, acid phosphooxye Polymerized (meth) acrylic acid esters such as acid (meth) acrylate, acid phosphooxypropyl (meth) acrylate, 3-chloro-2-acid phosphooxyethyl (meth) acrylate, and acid phosphooxypolyethylene glycol mono (meth) acrylate Acrylic resin formed by the above method. These compounds can be used individually by 1 type or in mixture of 2 or more types.

Wherein R ²¹ is H or CH ₃ , R ²² is an alkylene group having 2 or 3 carbon atoms, R ²³ is hydrogen, or an alkyl group having 1 to 20 carbon atoms which may contain a benzene ring, and n is 1 Represents an integer of ~ 15.)
In the general formula (XII), the alkyl group of R ²³ has 1 to 20 carbon atoms, and more preferably 1 to 10 carbon atoms. When the carbon number of the alkyl group of R ²³ is from 1 to 10 to suppress the proximity between the resin becomes an alkyl group an obstacle, the stability of the effect is obtained photosensitive color composition for promoting adsorption / orientation of the pigment However, if the number of carbon atoms exceeds 10, the steric hindrance effect of the alkyl group increases, and the adsorption / orientation of the benzene ring to the pigment also tends to be hindered, so the stability of the photosensitive coloring composition decreases. To do. This tendency becomes more prominent as the carbon chain length of the alkyl group of R ²³ becomes longer. When the carbon number exceeds 20, the adsorption / orientation of the benzene ring extremely decreases. Examples of the alkyl group containing a benzene ring represented by R ²³ include a benzyl group and a 2-phenyl (iso) propyl group.

  Examples of the compound represented by the general formula (XII) include phenol ethylene oxide (EO) modified (meth) acrylate, paracumylphenol EO or propylene oxide (PO) modified (meth) acrylate, and nonylphenol EO modified (meta). ) Acrylate, nonylphenol PO-modified (meth) acrylate, and the like. Of these compounds, EO or PO-modified (meth) acrylate of paracumylphenol not only has the effect of the π electron of the benzene ring, but also its steric effect, and forms a good adsorption / orientation plane to the thickness direction. Since the phase difference value Rth can be expressed, the effect is higher.

  In addition, since the acrylic resin contains 70 to 90 mol% of aromatic-containing monomer, when a photosensitive resin composition is prepared by blending this acrylic resin, charge transfer between aromatics is facilitated and electrical characteristics. Will improve.

  Examples of the photosensitive resin include (meth) acrylic compounds having a reactive substituent such as an isocyanate group, an aldehyde group, and an epoxy group on a linear polymer having a reactive substituent such as a hydroxyl group, a carboxyl group, or an amino group, A resin obtained by reacting an acid and introducing a photocrosslinkable group such as a (meth) acryloyl group or a styryl group into the linear polymer is used. In addition, linear polymers containing acid anhydrides such as styrene-maleic anhydride copolymer and α-olefin-maleic anhydride copolymer can be obtained from (meth) acrylic compounds having hydroxyl groups such as hydroxyalkyl (meth) acrylate. Half-esterified products are also used.

  Other suitable resins used in the present embodiment include, for example, polyester resin, polystyrene, styrene-maleic acid copolymer, polyimide resin, epoxy resin, benzoguanamine resin, melamine resin, urea resin, novolak resin, and polyvinylphenol resin. One or more selected from the above can be selected. Moreover, what modified | denatured these etc. are mentioned. Among these, a photopolymerizable unsaturated group-containing resin obtained by further reacting a reaction product of an epoxy resin and an unsaturated group-containing carboxylic acid or its anhydride with a polybasic carboxylic acid or its anhydride, or a novolak A resin, a resin having a phenolic hydroxyl group such as a polyvinylphenol resin, or a modified resin thereof is particularly preferable from the viewpoint of developability, patterning characteristics, cost, and the like.

  Examples of the thermoplastic resin include butyral resin, styrene-maleic acid copolymer, chlorinated polyethylene, chlorinated polypropylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyurethane resin, and polyester resin. , Acrylic resins, alkyd resins, polystyrene, polyamide resins, rubber resins, cyclized rubber resins, celluloses, polyethylene, polybutadiene, polyimide resins, and the like. Examples of the thermosetting resin include epoxy resins, benzoguanamine resins, rosin-modified maleic acid resins, rosin-modified fumaric acid resins, melamine resins, urea resins, and phenol resins.

  Surfactants include polyoxyethylene alkyl ether sulfate, sodium dodecylbenzenesulfonate, alkali salt of styrene-acrylic acid copolymer, sodium alkylnaphthalenesulfonate, sodium alkyldiphenyletherdisulfonate, lauryl sulfate monoethanolamine, lauryl Anionic surfactants such as triethanolamine sulfate, ammonium lauryl sulfate, monoethanolamine stearate, sodium stearate, sodium lauryl sulfate, monoethanolamine of styrene-acrylic acid copolymer, polyoxyethylene alkyl ether phosphate; Polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene Nonionic surfactants such as alkyl ether phosphates, polyoxyethylene sorbitan monostearate, and polyethylene glycol monolaurate; chaotic surfactants such as alkyl quaternary ammonium salts and their ethylene oxide adducts; alkyldimethylamino Examples include amphoteric surfactants such as alkylbetaines such as betaine acetate and alkylimidazolines, and these can be used alone or in admixture of two or more.

  Polymerizable monomers and oligomers that can be used include methyl (meth) acrylate, ethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, cyclohexyl (meth) acrylate, β- Carboxyethyl (meth) acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, triethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) ) Acrylate, polyethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, 1,6-hexanediol diglycidyl ether di (meth) acrylate, Sphenol A diglycidyl ether di (meth) acrylate, neopentyl glycol diglycidyl ether di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tricyclodecanyl (meth) acrylate, ester acrylate, melamine (meth) acrylate Acrylic acid esters and methacrylic acid esters, (meth) acrylic acid esters of methylolated melamine, epoxy (meth) acrylates, urethane acrylates and other acrylic acid esters and methacrylic acid esters, (meth) acrylic acid, styrene, acetic acid Vinyl, hydroxyethyl vinyl ether, ethylene glycol divinyl ether, pentaerythritol trivinyl ether, (meth) acrylamide, N-hydroxymethyl ( And (meth) acrylamide, N-vinylformamide, acrylonitrile and the like.

  Moreover, it is preferable to use the polyfunctional urethane acrylate which has the (meth) acryloyl group obtained by making polyfunctional isocyanate react with the (meth) acrylate which has a hydroxyl group. The combination of the (meth) acrylate having a hydroxyl group and the polyfunctional isocyanate is arbitrary and is not particularly limited. Moreover, one type of polyfunctional urethane acrylate may be used alone, or two or more types may be used in combination. These can be used alone or in admixture of two or more.

  When the composition is cured by ultraviolet irradiation, a photopolymerization initiator or the like is added to the colored resin composition.

  As photopolymerization initiators, 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- Acetophenone compounds such as hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl Benzoin compounds such as dimethyl ketal, benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, , 3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, benzophenone compounds, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, 2,4 Thioxanthone compounds such as 2-diethylthioxanthone, 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4 6-bis (trichloromethyl) -s-triazine, 2- (p-tolyl) -4,6-bis (trichloromethyl) -s-triazine, 2-piphenyl-4,6-bis (trichloromethyl) -s- Triazine, 2-piperonyl-4,6-bis (trichloromethyl) -s-triazine, 2,4-bis (trichloromethyl)- 6-styryl-s-triazine, 2- (naphth-1-yl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxy-naphth-1-yl) -4,6- Triazine compounds such as bis (trichloromethyl) -s-triazine, 2,4-trichloromethyl- (piperonyl) -6-triazine, 2,4-trichloromethyl (4′-methoxystyryl) -6-triazine, 2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], O- (acetyl) -N- (1-phenyl-2-oxo-2- (4′-methoxy-) Oxime ester compounds such as naphthyl) ethylidene) hydroxylamine, phosphine compounds such as bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide , 9,10-phenanthrenequinone, camphor quinone, quinone-based compounds such as ethyl anthraquinone, borate compounds, carbazole compounds, imidazole compounds, titanocene compounds and the like.

  These photopolymerization initiators can be used alone or in combination. The amount of the photopolymerization initiator used is preferably 0.5 to 50% by weight, more preferably 3 to 30% by weight, based on the total solid content of the colored composition.

  Furthermore, as a sensitizer, α-acyloxy ester, acylphosphine oxide, methylphenylglyoxylate, benzyl, 9,10-phenanthrenequinone, camphorquinone, ethylanthraquinone, 4,4′-diethylisophthalo Compounds such as phenone, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, triethanolamine, methyldiethanolamine, triisopropanolamine, methyl 4-dimethylaminobenzoate, 4-dimethylaminobenzoate Ethyl 4-methylaminobenzoate, 2-dimethylaminoethyl benzoate, 2-dimethylhexyl 4-dimethylaminobenzoate, N, N-dimethylparatoluidine, 4,4′-bis (dimethylamino) benzophenone, 4 , 4'-bis (diechi Amino) benzophenone, can be used in combination of 4,4'-bis (ethylmethylamino) amine compounds such as benzophenone.

  These sensitizers can be used alone or in combination. The amount of the sensitizer used is preferably 0.5 to 60% by weight, more preferably 3 to 40% by weight based on the total amount of the photopolymerization initiator and the sensitizer. Moreover, it is preferable to use together a polymerization initiator and a photosensitizer. As a sensitizer, can also be used in combination.

  The colored resin composition can contain a polyfunctional thiol that functions as a chain transfer agent.

  The polyfunctional thiol may be a compound having two or more thiol groups. For example, hexanedithiol, decanedithiol, 1,4-butanediol bisthiopropionate, 1,4-butanediol bisthioglycolate, ethylene Glycol bisthioglycolate, ethylene glycol bisthiopropionate, trimethylolpropane tristhioglycolate, trimethylolpropane tristhiopropionate, trimethylolpropane tris (3-mercaptobutyrate), pentaerythritol tetrakisthioglycolate, Pentaerythritol tetrakisthiopropionate, tris (2-hydroxyethyl) isocyanurate trimercaptopropionate, 1,4-dimethylmercaptobenzene, 2,4,6-trimercapto-s-to Azine, 2- (N, N- dibutylamino) -4,6-dimercapto -s- triazine.

  These polyfunctional thiols can be used alone or in combination. The amount of the polyfunctional thiol used is preferably 0.1 to 30% by weight, more preferably 1 to 20% by weight, based on the total solid content of the colored composition. If it is less than 0.1% by mass, the effect of adding a polyfunctional thiol is insufficient, and if it exceeds 30% by mass, the sensitivity is too high and the resolution is lowered.

  The colored resin composition can contain a storage stabilizer in order to stabilize the viscosity with time of the composition. Examples of the storage stabilizer include quaternary ammonium chlorides such as benzyltrimethyl chloride and diethylhydroxyamine, organic acids such as lactic acid and oxalic acid, and organic acids such as methyl ether, t-butylpyrocatechol, triethylphosphine, and triphenylphosphine. Examples thereof include phosphine and phosphite. The storage stabilizer can be contained in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the pigment in the coloring composition.

  The colored resin composition can also contain an adhesion improver such as a silane coupling agent in order to enhance the adhesion to the substrate. Examples of the silane coupling agent include vinyl silanes such as vinyltris (β-methoxyethoxy) silane, vinylethoxysilane, and vinyltrimethoxysilane, (meth) acrylsilanes such as γ-methacryloxypropyltrimethoxysilane, β- (3 , 4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) methyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, β- (3,4-epoxycyclohexyl) ) Epoxysilanes such as methyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β ( Aminoethyl) γ-aminopro Lutriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N Examples include aminosilanes such as -phenyl-γ-aminopropyltriethoxysilane, thiosilanes such as γ-mercaptopropyltrimethoxysilane, and γ-mercaptopropyltriethoxysilane. The silane coupling agent can be contained in an amount of 0.01 to 100 parts by weight with respect to 100 parts by weight of the pigment in the coloring composition.

  The colored resin composition can contain an organic solvent as necessary. Examples of organic solvents include cyclohexanone, ethyl cellosolve acetate, butyl cellosolve acetate, 1-methoxy-2-propyl acetate, diethylene glycol dimethyl ether, ethylbenzene, ethylene glycol diethyl ether, xylene, ethyl cellosolve, methyl-n amyl ketone, propylene glycol monomethyl ether, toluene , Methyl ethyl ketone, ethyl acetate, methanol, ethanol, isopropyl alcohol, butanol, isobutyl ketone, petroleum solvent, and the like. These may be used alone or in combination. The solvent can be used in an amount of 800 to 4000 parts by weight, preferably 1000 to 2500 parts by weight with respect to 100 parts by weight of the pigment in the coloring composition.

  The coloring composition can be prepared in the form of gravure offset printing ink, waterless offset printing ink, inkjet ink, silk screen printing ink, solvent development type or alkali development type color resist. The colored resist is obtained by dispersing a dye in a composition containing a thermoplastic resin, a thermosetting resin or a photosensitive resin, a monomer, a photopolymerization initiator, and an organic solvent.

  The pigment is preferably contained in a proportion of 5 to 70% by weight based on the total solid content of the colored composition (100% by weight). More preferably, it is contained in a proportion of 20 to 50% by weight, and the remainder consists essentially of a resinous binder provided by a pigment carrier.

  The colored composition is removed by means of centrifugal separation, sintering filter, membrane filter, etc. to remove coarse particles of 5 μm or more, preferably coarse particles of 1 μm or more, more preferably 0.5 μm or more and coarse particles It is preferable to carry out.

  The red pixel, the green pixel, and the blue pixel in the colored layer of the COA substrate are formed on the transparent substrate by using the above-described colored compositions by a printing method or a photolithography method.

  As the transparent substrate, glass plates such as soda lime glass, low alkali borosilicate glass and non-alkali alumino borosilicate glass, and resin plates such as polycarbonate, polymethyl methacrylate, and polyethylene terephthalate are used. In addition, a transparent electrode made of a combination of metal oxides such as indium oxide, tin oxide, zinc oxide and antimony oxide is formed on the surface of the glass plate or resin plate for driving the liquid crystal after the liquid crystal panel is formed. Also good.

  The formation of each color filter segment by the printing method can be patterned simply by repeating the printing and drying of the colored composition prepared as the above-mentioned various printing inks. Excellent in properties. Furthermore, it is possible to print a fine pattern having high dimensional accuracy and smoothness by the development of printing technology. In order to perform printing, it is preferable that the ink does not dry and solidify on the printing plate or on the blanket. Control of ink fluidity on a printing press is also important, and ink viscosity can be adjusted with a dispersant or extender pigment.

  The ink jet method is a method in which an ink jet apparatus in which a plurality of fine discharge ports (ink jet heads) are arranged for each color is directly printed on a transparent substrate or a substrate on which an active element such as a TFT is formed.

  When forming each color pixel by photolithography, a coating composition such as spray coating, spin coating, slit coating, roll coating, or the like is applied to the transparent composition on the transparent composition prepared as the solvent development type or alkali development type coloring resist. To apply a dry film thickness of 0.2 to 10 μm.

  When drying the coating film, a vacuum dryer, a convection oven, an IR oven, a hot plate, or the like may be used. If necessary, the dried film is exposed to ultraviolet light through a mask having a predetermined pattern provided in contact with or non-contact with the film.

  Then, after immersing in a solvent or an alkaline developer or spraying the developer by spraying or the like to remove the uncured portion to form a desired pattern, the same operation is repeated for other colors to repeat the coloring layer of the COA substrate Can be manufactured.

  Furthermore, in order to accelerate the polymerization of the colored resist, heating can be performed as necessary.

According to the photolithography method, a colored layer of the COA substrate can be manufactured with higher accuracy than the printing method.

  In development, an aqueous solution such as sodium carbonate or sodium hydroxide is used as an alkali developer, and an organic alkali such as dimethylbenzylamine or triethanolamine can also be used. Moreover, an antifoamer and surfactant can also be added to a developing solution. As a development processing method, a shower development method, a spray development method, a dip (immersion) development method, a paddle (liquid accumulation) development method, or the like can be applied.

  In order to increase the UV exposure sensitivity, after coating and drying the colored resist, a water-soluble or alkaline water-soluble resin such as polyvinyl alcohol or a water-soluble acrylic resin is applied and dried to form a film that prevents polymerization inhibition by oxygen. Thereafter, ultraviolet exposure can also be performed.

  The colored layer of the COA substrate suitably used for the liquid crystal display device according to the present embodiment can be produced by an electrodeposition method, a transfer method, an ink jet method or the like in addition to the above method.

  The electrodeposition method is a method of manufacturing a color filter by electrodepositing each color filter segment on a transparent conductive film by electrophoresis of colloidal particles using a transparent conductive film formed on a transparent substrate. The transfer method is a method in which a colored layer of a COA substrate is formed in advance on the surface of a peelable transfer base sheet, and this colored layer is transferred to a desired transparent substrate.

  Subsequently, development is performed. An alkaline aqueous solution can be used as the developer. As an example of the alkaline aqueous solution, a tetramethylammonium hydroxide aqueous solution or a potassium hydroxide aqueous solution is preferably used, but a sodium carbonate aqueous solution, a sodium hydrogen carbonate aqueous solution, a mixed aqueous solution thereof, or a surfactant suitable for them. You may use what added. After development, the pixel of any one color can be obtained by washing with water and drying.

  By repeating the above-described series of steps by changing the photosensitive coloring composition and pattern and by the required number of colors, it is possible to obtain a colored pattern in which necessary colors are combined, that is, a plurality of pixels.

  Next, a method for manufacturing the liquid crystal display device according to this embodiment will be described.

  FIG. 3 is a flowchart showing a process for manufacturing the liquid crystal display device according to the present embodiment.

  As shown in FIG. 3, in manufacturing a liquid crystal display device, it is necessary to perform an alignment process on the COA substrate and the counter substrate. In the alignment treatment, an alignment film is formed on the side of the liquid crystal display substrate in contact with the liquid crystal, and if necessary, the liquid crystal direction at the liquid crystal interface of the liquid crystal display substrate is uniformly aligned. .

  Since the alignment film has the property of aligning the liquid crystal in a predetermined direction, it is necessary to select the alignment film in accordance with a predetermined liquid crystal mode. As the material for the alignment film, photosensitive or non-photosensitive materials such as polyimide resins, polyamide resins, and polyvinyl alcohol resins are preferably used, but are not limited thereto. However, a polyimide resin is preferable from the viewpoint of heat resistance and reliability of the alignment film.

An alignment film using a polyimide resin is obtained by forming a soluble polyimide solution or a polyamic acid solution on a substrate for a liquid crystal display device, and then drying, firing, or light irradiation as necessary. The alignment film material is formed on the substrate for a liquid crystal display device by flexographic printing, spin coating, roll coating, slit die coating, silk printing, ink jet printing, or the like. The polyimide resin preferably used as the alignment film is not particularly limited, but a polyamic acid obtained by imidation with heating or an appropriate catalyst is preferably used.
In order to manufacture the liquid crystal display device according to the present embodiment, a commercially available alignment film may be used. For example, AL1000, AL1068, AL1072, AL1077, AL1F00, AL3000, AL4000, AL5000, AL6000, AL7000, AL8000, AL1H659, AL60101, AL60601, JALS-146, JALS-212, JALS-246, manufactured by JSR JALS-445, JALS-469, JALS-550, JALS-552, JALS-553, JALS-555, JALS-556, JALS-566, JALS-725, JALS-1082, JALS-1085, JALS-1216, Chisso PIA-5140, PIA-5150, PIA-5310, PIA-X322, PIA-2024, PIA-2700, PIA-2800, P A-2900, SE-130, SE-150, SE-2110, SE-410, SE-610, SE-1180, SE-2170, SE-1211, SE-1410, SE-3140, SE manufactured by Nissan Chemical Co., Ltd. -3210, SE-3310, SE-3510, SE-5291, SE-5300, SE-6210, SE-7492, SE-7992, SE-7511L, SE-8192L, RN-1322, RN-1332, RN-1349 , RN-1358, RN-1386, RN-1417, RN-1436, RN-1450, RN-1477, RN-1486, etc. may be used alone, or two or more of these may be used in combination. In addition, other polymer components may be added as appropriate, and resin components contained in these products may be selected as appropriate. It may be used.

  Solvents used for the alignment film solution include water, ethanol, methanol, isobutanol, alcohols such as 3-methyl-3-methoxybutanol, ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, diethyl ether, isopropyl Ethers such as ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, ethyl acetate, n-butyl acetate, 3-methoxy-3-methylbutyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol mono Ethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate Esters, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, esters such as γ-butyrolactone, amides such as N, N-dimethylformamide, N, N-dimethylacetamide, 2- Pyrrolidones such as pyrrolidone and N-methylpyrrolidone, butyl cellosolve and the like can be used.

  The process of uniformly aligning the direction of the liquid crystal at the liquid crystal interface is used in a liquid crystal display mode such as TN or IPS in which the liquid crystal director needs to be aligned near the horizontal of the liquid crystal display device substrate. For example, a rubbing process in which the alignment film is rubbed with a cloth such as cotton or a photo alignment process in which light with controlled polarization is irradiated is used.

  The thickness of the liquid crystal layer of the liquid crystal display device is maintained at a predetermined value using a columnar spacer or a colored pixel laminated photo spacer. The columnar spacer can be formed by using a photosensitive resin on the color filter substrate by a photolithography method or the like. The colored pixel laminated photo spacer is configured by laminating at least one of other colored dot patterns on the colored layer. These colored dot patterns can be formed simultaneously with the formation of the colored pixels of the three colors by using the same material as that of the colored layer used for forming the green pixel, the red pixel, and the blue pixel. Lamination is performed with one or two other colored patterns on the colored layer, and the number of laminations may be appropriately selected according to the specifications of the photospacer.

  After the pixel electrode is provided on the entire surface of the glass substrate on which the colored pixel laminated photo spacer is formed, a slit is formed by photoetching, but the electrode on the colored pixel laminated photo spacer is electrically shorted with the counter substrate. In order to prevent this, it is necessary to remove it by photoetching simultaneously with the formation of the slit.

  For measuring the height of column spacers or colored pixel laminated photo spacers, it is possible to use a contact-type film thickness meter such as a stylus-type film thickness meter, or a non-contact film thickness measuring device such as an optical interferometer or laser microscope. However, it is desirable to use a non-contact film thickness meter in consideration of contamination on the substrate and measurement accuracy.

  In the manufacture of a liquid crystal display device, a sealant that fixes liquid crystal between a pair of substrates for a liquid crystal display device can be a photo-curing resin such as an acrylic resin or a thermosetting resin such as an epoxy resin, Alternatively, a resin mixture of both a light curable resin and a thermosetting resin can be used.

  The liquid crystal material used in the liquid crystal display device can be appropriately selected according to the display mode and the driving method, and is not particularly limited. As the nematic liquid crystal used in the liquid crystal display device according to the present embodiment, for example, a material having a positive dielectric anisotropy Δε or a material having a negative dielectric anisotropy can be used as appropriate.

  In order to manufacture the liquid crystal display device according to the present embodiment, a commercially available liquid crystal may be used. For example, MLC-6601, MLC-6614, MLC-6686, MLC-6669, MLC-6608, MLC-6609, MLC-6610, MLC-6222, MLC-6252, MLC-6256, MLC-6625, MLC manufactured by Merck -6628 or the like can be used.

  A plunger pump type dispenser is used for dropping the liquid crystal material onto the liquid crystal display device substrate. The dispenser for dropping a liquid crystal material introduces a liquid crystal material into a cylindrical casing, and drops a liquid crystal from a nozzle by moving an elongated rod-shaped plunger in a vertical direction. The drop amount of the liquid crystal material is adjusted by the amount of movement of the plunger using the pump controller.

  The pressure reduction performed when the pair of color filter substrates and the array substrate are bonded is preferably performed at 1 Pa or less. When bonding is performed at a pressure exceeding 1 Pa, the liquid crystal material does not spread sufficiently, or volatile gas is generated from the color filter material, liquid crystal material, etc. after bonding and bubbles are generated in the liquid crystal cell. There are things to do.

  Ultraviolet (UV) irradiation is used to cure the sealant. When performing UV irradiation, it is necessary to prevent light from being applied to the display pixel portion. After UV irradiation is performed on the sealant, heat treatment is usually performed at 100 to 150 ° C. for 30 to 90 minutes. By this heat treatment, the sealant is thermally cured, and by applying heat higher than the phase transition temperature of the liquid crystal material, realignment of the liquid crystal material can be promoted. After cutting the liquid crystal display substrate thus obtained, an IC, a polarizing plate, and a backlight unit are attached to complete the liquid crystal display device.

  The liquid crystal display device according to the present embodiment can include a retardation film as an optical compensation layer in order to expand the viewing angle. As a retardation film, a stretched birefringent polymer film has been conventionally used. However, an optical film formed of a low-molecular or high-molecular liquid crystalline compound on a transparent support instead of an optical compensation sheet made of a stretched birefringent film. Use an optical compensation layer having an anisotropic layer, or use an optical compensation layer having an optical anisotropic layer made of a low-molecular or high-molecular liquid crystalline compound in addition to the optical compensation layer made of a stretched birefringent film. May be. Further, this optical compensation layer may be formed inside the liquid crystal cell.

  The optical properties of the retardation film are determined according to the optical properties of the liquid crystal cell, specifically the display mode difference as described above. For example, the retardation film for IPS mode depends on the viewing angle of the polarizing plate. To reduce the brightness of black display in all directions and improve the viewing angle characteristic of contrast. In addition, by designing the optical properties of the retardation film to an optimum value for each wavelength of light, it is possible to provide a liquid crystal display device having a wide visual field characteristic with little color change. In particular, it is effective when combined with multi-gap or multi-domain. Further, the viewing angle can be narrowed so that the display can be observed only from a specific direction, instead of enlarging the viewing angle.

  As a retardation film that can be used in the present embodiment, a rod-like film is formed on a support made of a polymer film obtained by stretching a cyclic olefin resin such as cycloolefin polymer (hereinafter referred to as COP) or a cellulose resin such as TAC. The film which formed the optically anisotropic layer which consists of a composition containing a liquid crystalline molecule | numerator and a discotic liquid crystalline compound is mentioned.

  Examples of rod-like liquid crystalline molecules include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines. , Phenyldioxanes, tolanes, and alkenylcyclohexylbenzonitriles (Chemical Review, Vol. 22, Chemistry of Liquid Crystals (1994), Chapters 4, 7 and 11 of the Chemical Society of Japan, and liquid crystal devices) (Refer to Chapter 3 of the 142th Committee of the Japan Society for the Promotion of Science).

  The discotic liquid crystalline compound is C.I. Destrade et al. Mol. Crysr. Liq. Cryst. , Vol. 71, page 111 (1981); edited by the Chemical Society of Japan, quarterly chemistry review, No. 22, Liquid Crystal Chemistry, Chapter 5, Chapter 10, Section 2 (17) (1994); Kohne et al. , Angew. Chem. Soc. Chem. Comm. , Page 1794 (1985); Zhang et al. , J .; Am. Chem. Soc. , Vol. 116, page 2655 (1994)) or the like can be used.

  As the retardation film, a non-liquid crystalline polymer is suitably used since it is excellent in heat resistance, chemical resistance, transparency, and has high rigidity.

  Examples of the polymer include polymers such as polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide, and polyimide is particularly preferable from the viewpoint of high orientation and high transparency.

  A commercially available retardation film can also be used. For example, manufactured by Nippon Zeon Co., Ltd. (trade name “Zeonor”), manufactured by JSR Corporation (trade name “Arton”), N-TAC series manufactured by Konica Minolta Co., Ltd., Fuji Photo Film Co., Ltd. Examples include the Fujitac series.

Thus, according to this embodiment, in order to obtain a color filter with higher contrast, the thickness of the green pixel layer constituting the color filter can be determined by specifying the pigment type to be used or by miniaturizing the pigment. Even if there is a possibility that the directional phase difference value may be negative, select a pigment that can be a positive thickness direction phase difference, perform a refinement process that makes it positive, and also a positive thickness direction phase difference It is possible to provide a coloring composition for a color filter that can be adjusted to an optimum value so that the thickness direction retardation value is a positive value and satisfies formula (2) by adding fine particles that can be adjusted to It becomes.

  Furthermore, according to another embodiment of the present invention, a liquid crystal display device was manufactured using the above-described color filter so as to be suitable for the optical characteristics of the optical compensation layer and other components, particularly the wavelength dispersion characteristics of retardation. In this case, since the polarization state of the light passing through the display area of each colored pixel does not vary, a liquid crystal display device excellent in viewing angle display from an oblique direction can be obtained.

  Furthermore, since the display is black with the viewing angle compensated from the oblique direction, the color shift can be reduced and neutral black can be reproduced when viewed from the oblique direction, and the display characteristics are very good. it can.

  Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited thereto without departing from the spirit of the present invention. In addition, since materials used in this embodiment are extremely sensitive to light, it is necessary to prevent exposure to unnecessary light such as natural light, and it goes without saying that all operations are performed under a yellow or red light. Yes. In the examples and comparative examples, “parts” means “parts by weight”.

  The symbol of the pigment indicates a color index number. For example, “PR254” represents “CI Pigment Red 254” and “PY150” represents “CI Pigment Yellow 150”.

The dye derivatives used in the following examples are shown in Table 1 below.

a) Production of refined pigments The refined pigments used in Examples and Comparative Examples were produced by the following method. And the average primary particle diameter of the obtained pigment was measured by the general method which measures the magnitude | size of a primary particle directly from an electron micrograph.

  Specifically, the particles in the field of view are photographed with a transmission electron microscope JEM-2010 (manufactured by JEOL Ltd.), and the minor axis diameters of the primary particles of the individual pigments constituting the aggregate on the two-dimensional image The major axis diameter was measured, and the average was taken as the particle diameter of the pigment particles.

  Next, for 100 or more pigment particles, the volume (weight) of each particle was obtained by approximating the obtained particle size to a rectangular parallelepiped, and the volume average particle size was defined as the average primary particle size. At this time, the colored composition as a sample is ultrasonically dispersed in a solvent, and then the particles are photographed with the microscope. The same result can be obtained by using either a transmission type (TEM) or a scanning type (SEM). The primary particle diameter referred to here represents a particle diameter (equivalent circle diameter) corresponding to 50% of the total amount in the cumulative curve of the number particle size distribution.

[Production Example 1]
A sulfonation flask was charged with 170 parts of tert-amyl alcohol under a nitrogen atmosphere. Then 11.04 parts of sodium were added and the mixture was heated to 92-102 ° C. The molten sodium was then held overnight at 100-107 ° C. with vigorous stirring.

  A solution prepared by dissolving 44.2 parts of 4-chlorobenzonitrile and 37.2 parts of diisopropyl succinate in 50 parts of tert-amyl alcohol at 80 to 98 ° C. was dissolved in the obtained solution. Introduced over 2 hours. After the introduction, the reaction mixture was stirred at 80 ° C. for a further 3 hours and at the same time 4.88 parts of diisopropyl succinate were added dropwise.

  The reaction mixture was cooled to room temperature and added to a 20 ° C. mixture of 270 parts of methanol, 200 parts of water, and 48.1 parts of concentrated sulfuric acid and stirring was continued at 20 ° C. for 6 hours. The red mixture was filtered, and the residue was washed with methanol and water and then dried at 80 ° C. to obtain 46.7 parts of a red pigment (R-1) of diketopyrrolopyrrole.

[Production Example 2]
100 parts of diketopyrrolopyrrole red pigment PR254 ("Irgafoa Red B-CF" manufactured by Ciba Specialty Chemicals; R-1), 18 parts of dye derivative (D-1), 1000 parts of crushed salt, and 120 parts of diethylene glycol Was charged into a stainless steel 1 gallon kneader (manufactured by Inoue Seisakusho) and kneaded at 60 ° C. for 10 hours.

  The mixture was added to 2000 parts of warm water, heated to about 80 ° C. and stirred with a high speed mixer for about 1 hour to form a slurry, filtered and washed repeatedly to remove salt and solvent, and then at 80 ° C. for 24 hours. Dried to obtain 115 parts of a salt milled pigment (R-2). The primary particle diameter of the obtained pigment is shown in Table 2 below.

[Production Example 3]
100 parts of anthraquinone red pigment PR177 (“Chromophthal Red A2B” manufactured by Ciba Specialty Chemicals), 8 parts of a dye derivative (D-2), 700 parts of crushed salt, and 180 parts of diethylene glycol are made of 1 gallon kneader made of stainless steel (Inoue Seisakusho) And kneaded at 70 ° C. for 4 hours.

  The mixture was put into 4000 parts of warm water, heated to about 80 ° C., stirred with a high speed mixer for about 1 hour to form a slurry, filtered and washed with water to remove salt and solvent, and then at 80 ° C. for 24 hours. Drying gave 102 parts of salt milled pigment (R-3). The primary particle diameter of the obtained pigment is shown in Table 2 below.

[Production Example 4]
120 parts of halogenated copper phthalocyanine-based green pigment PG36 (“Rionol Green 6YK” manufactured by Toyo Ink Manufacturing Co., Ltd.), 1600 parts of crushed sodium chloride, and 270 parts of diethylene glycol were charged into a 1 gallon kneader (manufactured by Inoue Seisakusho) at 70 ° C. And kneaded for 12 hours.

  The mixture was poured into 5000 parts of warm water, stirred at a high speed mixer for about 1 hour while being heated to about 70 ° C. to form a slurry, filtered and washed repeatedly to remove salt and solvent, and then at 80 ° C. for 24 hours. It dried and obtained 117 parts of salt milling pigment (G-1).

The primary particle diameter of the obtained pigment is shown in Table 2 below.

[Production Example 5]
In a molten salt of 200 ° C. of 356 parts of aluminum chloride and 6 parts of sodium chloride, 46 parts of zinc phthalocyanine was dissolved, cooled to 130 ° C., and stirred for 1 hour. The reaction temperature was raised to 180 ° C., and bromine was added dropwise at 10 parts per hour for 10 hours. Thereafter, chlorine was introduced at 0.8 parts per hour for 5 hours.

  The reaction solution was gradually poured into 3200 parts of water, then filtered and washed with water to obtain 107.8 parts of a crude zinc halide phthalocyanine pigment. The average number of bromine contained in one molecule of the crude zinc halide phthalocyanine pigment was 14.1 and the average number of chlorine was 1.9.

  120 parts of the obtained crude zinc halide phthalocyanine pigment, 1600 parts of crushed salt and 270 parts of diethylene glycol were charged into a stainless steel 1 gallon kneader (manufactured by Inoue Seisakusho) and kneaded at 70 ° C. for 12 hours.

  The mixture was poured into 5000 parts of warm water, stirred at a high speed mixer for about 1 hour while being heated to about 70 ° C. to form a slurry, filtered and washed repeatedly to remove salt and solvent, and then at 80 ° C. for 24 hours. It dried and obtained 117 parts of salt milling process pigments (G-2). The primary particle diameter of the obtained pigment is shown in Table 2 below.

[Production Example 6]
A separable flask was charged with 150 parts of water, and further stirred with 63 parts of 35% hydrochloric acid to prepare a hydrochloric acid solution. While paying attention to foaming, 38.7 parts of benzenesulfonyl hydrazide was charged, and ice was added until the liquid temperature became 0 ° C. or lower. After cooling, 19 parts of sodium nitrite was charged over 30 minutes, stirred for 30 minutes at 0 to 15 ° C., and then sulfamic acid was charged until no coloration was observed on the potassium iodide starch paper.

  Next, after adding 25.6 parts of barbituric acid, it heated up to 55 degreeC and stirred as it was for 2 hours. Next, 25.6 parts of barbituric acid was added, the temperature was raised to 80 ° C., and then sodium hydroxide was added until the pH reached 5. After further stirring for 3 hours at 80 ° C., the temperature was lowered to 70 ° C., followed by filtration and washing with warm water.

  The obtained press cake was reslurried in 1200 parts of warm water, and then stirred at 80 ° C. for 2 hours. Thereafter, filtration was performed at the same temperature, and washing with 2000 parts of water at 80 ° C. was performed with warm water, and it was confirmed that benzenephonamide was transferred to the filtrate side. The obtained press cake was dried at 80 ° C. to obtain 61.0 parts of disodium azobarbituric acid.

  Next, 200 parts of water was charged into a separable flask, and 8.1 parts of the obtained disodium azobarbituric acid powder was added and dispersed while stirring. After uniformly dispersing, the solution was heated to 95 ° C., and 5.7 parts of melamine and 1.0 part of diallylaminomelamine were added.

  Further, a green solution obtained by dissolving 6.3 parts of cobalt (II) chloride hexahydrate in 30 parts of water was added dropwise over 30 minutes. After completion of the dropwise addition, complexation was performed at 90 ° C. for 1.5 hours.

  Thereafter, the pH was adjusted to 5.5, and 2 parts of xylene, 0.4 part of sodium oleate, and 16 parts of water were pre-stirred to add 20.4 parts of the emulsion, and further heated for 4 hours. Stir. After cooling to 70 ° C., it was quickly filtered, and washing with warm water at 70 ° C. was repeated until the inorganic salt could be washed.

  Thereafter, 14 parts of an azo yellow pigment (Y-2) was obtained through drying and pulverization steps. The primary particle diameter of the obtained pigment is shown in Table 2 below.

[Production Example 7]
160 parts of yellow pigment (CI Pigment Yellow 138, “PALIOTOL YELLOW K0961HD” manufactured by BASF), 1600 parts of sodium chloride, and 270 parts of diethylene glycol (manufactured by Tokyo Chemical Industry Co., Ltd.) are charged into a 1 gallon kneader (manufactured by Inoue Seisakusho) made of stainless steel. It knead | mixed for 15 hours at 60 degreeC. Next, this mixture is poured into about 5 liters of warm water, heated to about 70 ° C. and stirred with a high speed mixer for about 1 hour to form a slurry, then filtered and washed to remove sodium chloride and diethylene glycol, It was dried at 80 ° C. for 24 hours to obtain 157 parts of salt milled pigment (Y-3).

[Production Example 8]
100 parts of copper phthalocyanine blue pigment PB15: 6 (“Rionol Blue ES” manufactured by Toyo Ink Manufacturing Co., Ltd.), 800 parts of crushed salt, and 100 parts of diethylene glycol were charged into a stainless steel 1 gallon kneader (manufactured by Inoue Seisakusho) at 70 ° C. And kneaded for 12 hours.

The mixture was poured into 3000 parts of warm water, stirred at a high speed mixer for about 1 hour while being heated to about 70 ° C. to form a slurry, filtered and washed repeatedly to remove salt and solvent, and then at 80 ° C. for 24 hours. It dried and obtained 98 parts of salt milling pigment (B-1). The primary particle diameter of the obtained pigment is shown in Table 2 below.

  “FANCHON FAST YELLOW Y-5688” (C.I. Pigment Yellow 150) manufactured by BAYER is used as yellow pigment 1.

b) Preparation of Retardation Adjuster (Resin Solution) A melamine compound (trade name “MX-750”) manufactured by Nippon Carbite Industries, Ltd. was used as the retardation adjuster. Other resins were prepared as shown below.

[Synthesis of Resin Solution (A-1)]
The reaction vessel was charged with 800 parts of cyclohexanone, heated while injecting nitrogen gas into the vessel, and a mixture of the following monomer and thermal polymerization initiator was added dropwise to carry out a polymerization reaction.

Styrene 60 parts Methacrylic acid 60 parts Methyl methacrylate 65 parts Butyl methacrylate 65 parts Thermal polymerization initiator 10 parts Chain transfer agent 3 parts After dripping and heated sufficiently, 2.0 parts of thermal polymerization initiator was dissolved in 50 parts of cyclohexanone. Then, the reaction was continued and an acrylic resin solution was obtained.

  An acrylic resin solution was prepared by adding cyclohexanone to the resin solution so that the non-volatile content was 20% by weight, and it was designated as resin solution (A-1). The weight average molecular weight of the acrylic resin was about 10,000.

[Synthesis of Resin Solution (A-2)]
In 392 parts of propylene glycol monomethyl ether acetate, 430 parts of cresol novolac type epoxy resin (Dainippon Ink "N-680") and 144 parts of acrylic acid were dissolved and reacted under reflux to obtain a cresol novolak type epoxy acrylate. . Next, 154 parts of hexahydrophthalic anhydride was added to this epoxy acrylate, and propylene glycol monomethyl ether acetate was added so as to have a solid content of 30% by weight to prepare an epoxy acrylate resin solution to obtain a resin solution (A-2). .

  The weight average molecular weight of the epoxy acrylate resin was about 8,000.

[Synthesis of Resin Solution (A-3)]
13 g of azobisisobutyronitrile is dissolved in 432 g of propylene glycol monomethyl ether acetate, heated to 80 ° C. while blowing nitrogen gas, 86.3 g of styrene, 11.8 g of acrylic acid, and EO modification of paracumylphenol (meta ) A mixture of 10.0 g of acrylate was added dropwise over 2 hours. Thirty minutes after the completion of dropping, 6.5 g of azoisobutyronitrile was added, and the mixture was further heated for 5 hours to prepare a styrene-acrylic acid copolymer to obtain a resin solution (A-3). The weight average molecular weight of the obtained styrene-acrylic acid copolymer was 3000.

c) Preparation of Pigment Dispersion Mixtures with the composition (weight ratio) shown in Table 3 below were uniformly stirred and mixed, then dispersed with a zirconia bead having a diameter of 1 mm for 5 hours with a sand mill, and then filtered with a 5 μm filter. Thus, each color pigment dispersion was obtained.

d) Preparation of colored composition (hereinafter referred to as resist) A mixture having the composition (weight ratio) shown in Table 4 below was uniformly stirred and mixed, and then filtered through a 1 μm filter to obtain each color resist.

e) Preparation of each color coating film Each color resist shown in the above Table 4 was applied to a glass substrate by spin coating, and then pre-baked at 70 ° C. for 20 minutes in a clean oven. Next, the substrate was cooled to room temperature and then exposed to ultraviolet rays using an ultrahigh pressure mercury lamp.

  Next, this substrate was spray-developed using an aqueous sodium carbonate solution at 23 ° C., then washed with ion-exchanged water and air-dried. Thereafter, post-baking was performed at 230 ° C. for 30 minutes in a clean oven to obtain each color coating film. The film thickness of the dried coating film was 3.0 μm in all cases.

f) Measurement of chromaticity, spectral transmittance, thickness direction retardation value, and contrast of each color coating film
[Chromaticity, spectral transmittance]
The chromaticity in the XYZ color system chromaticity diagram was measured using a spectrophotometer ("OSP-200" manufactured by Olympus).

[Thickness direction retardation value Rth]
The thickness direction retardation value can be obtained as follows. Using a transmission spectroscopic ellipsometer (“M-220” manufactured by JASCO Corporation), measurement is performed at a wavelength of every 5 nm in the range of 400 nm to 700 nm from the direction inclined 45 ° from the normal direction of the substrate on which the coating film is formed. Then, the ellipso parameter δ was obtained.

  The retardation value Δ (λ) at each wavelength can be obtained from Δ = δ / 360 × λ, and the three-dimensional refractive index is calculated using this value, and the thickness direction retardation value (Rth) is calculated from the following equation 4. Asked.

  Although Rth of each wavelength can be obtained from the above measurement, in this evaluation, the red pixel was calculated as 610 nm, the green pixel as 545 nm, and the blue pixel as 450 nm.

Rth = {(Nx + Ny) / 2−Nz} × d (4)
In the formula, Nx is a refractive index in the x direction in the plane of the colored pixel layer, Ny is a refractive index in the y direction in the plane of the colored pixel layer, and Nz is a refractive index in the thickness direction of the colored pixel layer. , Nx is a slow axis where Nx ≧ Ny. d is the thickness (nm) of the colored pixel layer.

[contrast]
A polarizing plate was placed on both sides of the substrate on which the coating film was formed, and the ratio of luminance (Lp) when the polarizing plate was parallel and luminance (Lc) when it was orthogonal, Lp / Lc was calculated as contrast (C).

  Further, contrast of only the substrate without colored pixels = Lp / Lc is CS, CR is a red pixel, CG is a green pixel, and CB is a blue pixel. Table 5 below shows the contrast and thickness direction retardation value Rth of each color coating film prepared from each color resist shown in Table 4 above.

  The luminance was measured using a color luminance meter (“BM-5A” manufactured by Topcon Corporation) under the condition of a 2 ° visual field, and “NPF-SEG1224DU” manufactured by Nitto Denko Corporation was used as the polarizing plate.

g) Preparation of COA substrate
[Example 1]
First, a TFT array is formed on the surface of the glass substrate, and a red resist (RR-2) is applied to the glass substrate by a spin coating method so as to have a final film thickness of 3 μm, and then in a clean oven at 70 ° C. Pre-baked for 20 minutes. Next, the substrate was cooled to room temperature, and then exposed to ultraviolet rays through a photomask using an ultrahigh pressure mercury lamp.

  Thereafter, the substrate was developed with an alkali developer at 23 ° C. for 90 seconds, washed with ion-exchanged water, and air-dried. Further, post-baking was performed at 230 ° C. for 30 minutes in a clean oven to form red pixels, which are striped colored layers, on a transparent substrate. The alkaline developer has the following composition. In the following examples and comparative examples, development is performed using this alkaline developer.

Sodium carbonate 1.5% by weight
Sodium bicarbonate 0.5% by weight
Anionic surfactant 8.0% by weight
("Peralex NBL" manufactured by Kao Corporation)
90% by weight of water
Next, using green resist (GR-3), green pixels were formed in the same manner, and further using blue resist (BR-2), blue pixels were formed in the same manner to obtain a COA substrate. . The formed film thickness of each color pixel was 3.0 μm.

h) Production of Liquid Crystal Display Device A pixel electrode was formed on the obtained COA substrate, and a polyimide alignment layer was formed thereon using Optomer AL60101 manufactured by JSR Corporation. A polarizing plate was formed on the other surface of this glass substrate. On the other hand, a polyimide alignment layer was formed on one surface of another (second) glass substrate using Optomer AL60101 manufactured by JSR Corporation. A polarizing plate was formed on the other surface of this substrate.

  The two glass substrates thus prepared face each other so that the electrode layers face each other, and are aligned using spacer beads while keeping the distance between both substrates constant, and the periphery is left so as to leave an opening for injecting the liquid crystal composition. Sealed with a sealant. A liquid crystal composition for VA (MLC-6610 manufactured by Merck & Co., Inc.) was injected from the opening, and the opening was sealed.

  In addition, as a polarizing plate, the polarizing plate with a phase difference plate (A) extract | collected with the glass from the AQUAS series (brand name LC42-RX1W) which is a commercially available liquid crystal television was used.

At this time, the optical parameters of the collected retardation films were as follows. (Unit: nm)
Polarizing plate with retardation plate (A) (collected from “AQUAS LC42-RX1W)”
(CF side)
Re 450 nm: 55.2, 545 nm: 54.7, 610 nm: 54.5
Rth 450 nm: 108.6, 545 nm: 109.4, 610 nm: 109.8
(TFT side)
Re 450 nm: 54.5, 545 nm: 55.0, 610 nm: 55.2
Rth 450 nm: 98.0, 545 nm: 105.7, 610 nm: 109.4
A VA display mode liquid crystal panel was obtained by combining the liquid crystal display device thus produced with a backlight unit collected from the commercially available liquid crystal television.

[Example 2]
The red resist is changed from (RR-2) to (RR-5), the green resist is changed from (GR-3) to (GR-5), and the blue resist is changed from (BR-2) to (BR-5). In the same manner as in Example 1, a liquid crystal display device was obtained.

[Example 3]
The red resist is changed from (RR-2) to (RR-7), the green resist is changed from (GR-3) to (GR-5), and the blue resist is changed from (BR-2) to (BR-5). In the same manner as in Example 1, a liquid crystal display device was obtained.

[Example 4]
The red resist is changed from (RR-2) to (RR-4), the green resist is changed from (GR-3) to (GR-4), and the polarizing plate with retardation plate (A) is the following polarizing plate with retardation plate (B) A liquid crystal display device was obtained in the same manner as in Example 1 except that the above was changed.

Polarizing plate with retardation plate (B): Samsung A series Product name LN
[Example 5]
Retardation plate for red resist from (RR-2) to (RR-8), green resist from (GR-3) to (GR-5), blue resist from (BR-2) to (BR-4) A liquid crystal display device was obtained in the same manner as in Example 1 except that the polarizing plate with the retardation plate (A) was replaced with the polarizing plate with the retardation plate (B).

[Example 6]
A red resist is changed from (RR-2) to (RR-8), a green resist is changed from (GR-3) to (GR-2), a blue resist is changed from (BR-2) to (BR-5), and a phase difference plate A liquid crystal display device was obtained in the same manner as in Example 1 except that the polarizing plate with the retardation plate (A) was replaced with the polarizing plate with the retardation plate (B).

[Comparative Example 1]
The green resist is changed from (GR-3) to (GR-1) and the blue resist is changed from (BR-2) to (BR-1) except that the green resist is changed from (GR-2) to (GR-1). A liquid crystal display device was obtained in the same manner as in Example 1.

[Comparative Example 2]
Except for changing the red resist from (RR-1) to (RR-4), the green resist is changed from (GR-3) to (GR-6), and the blue resist is changed from (BR-2) to (BR-1). A liquid crystal display device was obtained in the same manner as in Example 1.

[Comparative Example 3]
Retardation plate for red resist from (RR-2) to (RR-6), green resist from (GR-3) to (GR-7), blue resist from (BR-2) to (BR-5) A liquid crystal display device was obtained in the same manner as in Example 1 except that the polarizing plate with the retardation plate (A) was replaced with the polarizing plate with the retardation plate (B).

[Comparative Example 4]
Retardation plate with red resist from (RR-2) to (RR-6), green resist from (GR-3) to (GR-6), blue resist from (BR-2) to (BR-5) A liquid crystal display device was obtained in the same manner as in Example 1 except that the polarizing plate with the retardation plate (A) was replaced with the polarizing plate with the retardation plate (B).

j) Visibility evaluation at the time of black display of the liquid crystal display device The produced liquid crystal display device is displayed in black and leaks from the normal direction (substantially vertical direction) of the liquid crystal panel and from the direction (oblique) inclined 45 ° from the normal direction. The amount of light (orthogonal transmitted light; leakage light) was visually observed. Also, the chromaticity (u (、), v (⊥)) when viewed from a substantially vertical direction when displaying black and the chromaticity when viewed from an orientation inclined up to 60 ° from the normal direction of the display surface ( u (45), v (45)) were measured with Topcon BM-5A, the color difference Δu′v ′ was calculated, and the maximum value of Δu′v ′ at 0 ≦ θ ≦ 60 ° was determined. The evaluation rank is as follows, and the results are shown in Table 5 below.

k) Evaluation of burn-in and alignment failure of liquid crystal display device As a burn-in evaluation method, a so-called checker flag display in which a white display square and a black display square are in contact with each other for 200 hours and then a gray display is performed. The evaluation was made with ○ indicating that no afterimage was left and × indicating remaining.

  As a poor alignment evaluation method, when a 15 μm ITO slit is formed on a pixel electrode on a colored pixel and a white display is performed, the ITO slit portion that becomes a black display has a line width of 10 μm or more, and less than 10 μm Was marked with x.

Table 5 below shows the measurement results of dielectric loss tangent and relative permittivity and the evaluation results of display characteristics.

  From Table 5 above, the thickness direction retardation values of the red pixel, the green pixel, and the blue pixel layer of the COA substrate according to Examples 1 to 6 are formed so as to satisfy the above formulas (1) and (2). Therefore, by using the obtained COA substrate for the liquid crystal display device, the chromaticity difference between the normal direction and the oblique direction of the display surface is 0.02 or less, and the liquid crystal display having good visibility in the oblique direction. Could get the device.

  Moreover, in the liquid crystal display device provided with the COA substrate according to Examples 1 to 6, since high contrast was achieved in the front, a liquid crystal display device having good visibility also in the front direction was obtained.

  Furthermore, in the liquid crystal display device including the COA substrate according to the first to seventh embodiments, the relative permittivity of the red pixel, the green pixel, and the blue pixel of the COA substrate is 4.2 or less. Good display quality was obtained without causing a threshold deviation.

  In contrast, in the liquid crystal display devices including the COA substrates according to Comparative Examples 1 to 4, the thickness direction retardation values of the red pixel, the green pixel, and the blue pixel layer are expressed by the above formulas (1) and (2). Since it is not formed so as to satisfy both, the balance of the phase difference in the thickness direction of the red pixel, the green pixel, and the blue pixel is not good, and color misregistration occurs in an oblique direction, resulting in poor visibility.

  Further, in the liquid crystal display device including the COA substrate according to Comparative Examples 1 to 4, since the relative permittivity of any one of the red pixel, the green pixel, and the blue pixel of the COA substrate exceeds 4.2, A liquid crystal orientation defect, a burn-in phenomenon due to a drive voltage threshold shift and an orientation defect occurred, and good display characteristics could not be obtained.

  DESCRIPTION OF SYMBOLS 1 ... Counter substrate, 2 ... Element substrate (COA substrate), 3 ... Thin film transistor layer, 4 ... Liquid crystal layer, 11 ... Glass substrate, 12 ... Polarizing plate, 13 ... Common electrode (transparent conductive film), 14 ... Slit, 15 ... Alignment film, 21 ... glass substrate, 22 ... polarizing plate, 23 ... colored layer, 24 ... pixel electrode (transparent conductive film), 25 ... projection, 26 ... slit (opening of pixel electrode), 27 ... alignment film, 28 ... Colored pixel laminated spacer, 29 ... insulating dot pattern, 31 ... gate electrode, 32 ... gate insulating film, 33 ... protective layer, 34 ... semiconductor layer, 35 ... ohmic contact layer, 36 ... gate line.

Claims (9)

In a liquid crystal display device comprising a transparent substrate and an array substrate including an active element for driving liquid crystal, a pixel electrode, and a color filter, and the liquid crystal is sandwiched between the transparent substrate and the array substrate, the color filter includes: It has at least a red pixel, a green pixel, and a blue pixel, the relative dielectric constant of the colored layer constituting these pixels is in the range of 3.0 to 4.2, and the thickness direction retardation value Rth of the red pixel (R), the thickness direction retardation value Rth (G) of the green pixel, and the thickness direction retardation value Rth (B) of the blue pixel satisfy both the following formulas (1) and (2). Liquid crystal display device.
Rth (G) ≧ 0 (1)
Rth (B) <Rth (G)> Rth (R) (2)
(Where Rth (R) is a thickness direction retardation value for light having a wavelength of 610 nm passing through a red pixel, Rth (G) is a thickness direction retardation value for light having a wavelength of 545 nm passing through a green pixel, and Rth (B). Represents the thickness direction retardation value for light having a wavelength of 450 nm that passes through the blue pixel, and Rth (R), Rth (G), and Rth (B) are refractive in the thickness direction from the average in-plane refractive index of each pixel. (This is a value obtained by multiplying the value by the ratio and the pixel thickness (nm).)   2. The liquid crystal display device according to claim 1, wherein a thickness direction retardation value Rth (G) of the green pixel is in a range of 0 nm to 100 nm.   3. The liquid crystal display device according to claim 1, wherein the colored layer constituting the green pixel is formed by dispersing a green pigment containing a halogenated zinc phthalocyanine pigment.   The liquid crystal display device according to claim 1, wherein the pixel electrode is provided directly on the colored layer, and the colored layer is exposed from an opening of the pixel electrode.   The liquid crystal display device according to claim 1, wherein at least one color of the colored layer includes a retardation adjusting agent.   6. The liquid crystal display device according to claim 5, wherein the retardation adjusting agent is a compound having at least one planar structure group having at least one crosslinkable group.   7. The liquid crystal display device according to claim 1, wherein a dielectric loss tangent of the colored layer is 0.03 or less in a range of a liquid crystal driving frequency of 10 Hz to 500 Hz. The transparent substrate is a transparent substrate having an opening on the surface in contact with the liquid crystal and provided with a transparent conductive film for regulating the alignment of the liquid crystal, and the liquid crystal is homeotropic aligned in the absence of an electric field. The liquid crystal display device according to claim 1 , wherein the liquid crystal display device is a liquid crystal. The liquid crystal display device according to claim 1 , wherein the liquid crystal is homogeneously aligned liquid crystal in the absence of an electric field.

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