JP2010044285A - Color filter, liquid crystal cell equipped with the same and liquid crystal display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease a difference to be generated between a coloring level when white is displayed and the coloring level when black is displayed arises. <P>SOLUTION: A color filter, in which a plurality of colored domains different from one another in hues are arrayed regularly, satisfies CY<CX<CZ (wherein CX, CY and CZ of the color filter are defined by the predetermined model expressions and calculated by using the tristimulus values X, Y and Z in the CIE color space which are obtained by irradiating the color filter, which is interposed between a pair of polarizing plates of a parallel Nicol state and a crossed Nicol state, with light). A liquid crystal cell has the color filter having the CX, CY and CZ equal to one another within 10% error. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a color filter useful for a liquid crystal display device for color display, a liquid crystal cell including the same, and a liquid crystal display device.

Conventionally, a color filter used in a liquid crystal display device for color display has a problem that light scattering occurs due to a coloring material (pigment) used for manufacturing the color filter, thereby reducing the white / black contrast of the liquid crystal display device. Further, since this light scattering has a wavelength dependency, there is also a problem that coloring occurs in black light leakage. For the purpose of reducing the tint at the time of black display of the liquid crystal display device due to such a color filter, color filters having various characteristics have been proposed (for example, Patent Documents 1 to 3).
Japanese Patent No. 4041814 JP 2005-316439 A JP 2006-331937 A

  However, as a result of various studies by the present inventor, it has been found that even if the characteristics of the color filter are adjusted as proposed in the above-mentioned patent document, there is a difference in color in white display / black display. As a result of further examination of this cause, the color filter proposed in the above-mentioned patent document shows that one of the reasons for the tint in white display / black display is a light leakage colored in blue due to the birefringence of the liquid crystal layer. It was found that this characteristic is caused by the fact that the blue light leakage due to the birefringence of the liquid crystal layer is not taken into consideration.

  Accordingly, the present invention provides a color filter that contributes to reducing the occurrence of a color difference in white display / black display when incorporated in a liquid crystal display device; and white display / black. It is an object of the present invention to provide a liquid crystal cell and a liquid crystal display device in which a difference in color in display is reduced.

Means for solving the above problems are as follows.
[1] A color filter in which a plurality of colored domains having different hues are regularly arranged, and contrasts CX and CY calculated from the tristimulus values X, Y, and Z in the CIE color space according to the following definitions: And CZ satisfy CY <CX <CZ.
(CX, CY, and CZ of the color filters are respectively prepared as a pair of polarizing plates, and tristimulus values Xp1, Yp1 obtained by irradiating light with the color filter sandwiched between the pair of polarizing plates in a parallel Nicol state. And Zp1; tristimulus values Xc1, Yc1 and Zc1 obtained by irradiating light with the color filter sandwiched between the pair of polarizing plates in the crossed Nicol state; the pair of polarizing plates without the color filter sandwiched in the parallel Nicol state Tristimulus values Xp2, Yp2, and Zp2 obtained by irradiating light and tristimulus values Xc2, Yc2 obtained by irradiating light with the pair of polarizing plates sandwiching no color filter in a crossed Nicol state Zc2; and the following formula 1 / CX = Xc1 / Xp1-Xc2 / Xp2
1 / CY = Yc1 / Yp1-Yc2 / Yp2
1 / CZ = Zc1 / Zp1-Zc2 / Zp2
Respectively. )
[2] The color filter according to [1], wherein 3 × CY <CZ is satisfied.
[3] The color filter according to [1] or [2], wherein the plurality of colored domains having different hues include a red (R) domain, a green (G) domain, and a blue (B) domain.
[4] From the stimulus value Y in the CIE color space of each of the G layer and the B layer formed by separately coating the colored compositions as the raw materials of the G domain and the B domain on the glass with the same thickness. The color filters according to any one of [1] to [3], wherein the calculated contrasts CYG and CYB satisfy CYG × 4 ≦ CYB.
[5] Each of the R domain, the G domain, and the B domain contains one or more pigments, and the average particle diameters dr, dg, and db of the main pigments in the R domain, the G domain, and the B domain, The color filter according to any one of [1] to [4], wherein db <dr <dg is satisfied, and dg> 1.5 × db is satisfied.
[6] Each of the R domain, the G domain, and the B domain contains one or more pigments, and the aggregation degrees fr, fg, and fb of the main pigments in the R domain, the G domain, and the B domain are The color filter according to any one of [1] to [5], wherein fb <fr <fg is satisfied and fg> 1.5 × fb is satisfied.
[7] G domain and B domain each contain one or more pigments, average particle diameters dg and db of main pigments in G domain and B domain, and main pigments in G domain and B domain, respectively The color filter according to any one of [1] to [6], wherein the aggregation degrees fg and fb satisfy dg × fg> 1.5 × db × fb.
[8] Any of [1] to [4], wherein the R domain and the G domain are each colored with one or more pigments, and the B domain is colored with one or more dyes Color filter.
[9] A liquid crystal cell having the color filter according to any one of [1] to [8], wherein the contrast CX is calculated according to the following definition from each of the stimulus values X, Y, and Z in the CIE color space: A liquid crystal cell, wherein CY and CZ are equal to each other within an error of 10%.
(CX, CY, and CZ of the liquid crystal cell are respectively prepared as a pair of polarizing plates, and tristimulus values Xp1, Yp1 obtained by irradiating light with the liquid crystal cell sandwiched between the pair of polarizing plates in a parallel Nicol state. And Zp1; and tristimulus values Xc1, Yc1, and Zc1 obtained by irradiating light with the liquid crystal cell sandwiched between the pair of polarizing plates in the crossed Nicol state, and the following formula 1 / CX = Xc1 / Xp1
1 / CY = Yc1 / Yp1
1 / CZ = Zc1 / Zp1
Respectively. )
[10] The liquid crystal cell according to [9], which is in a vertical alignment mode.
[11] The liquid crystal cell according to [9] or [10], wherein CY is 5000 or more.
[12] A liquid crystal display device having a pair of polarizers and the liquid crystal cell of any one of [9] to [11] disposed therebetween.

  According to the present invention, there is provided a color filter that contributes to reducing the occurrence of a color difference in white display / black display when incorporated in a liquid crystal display device; and white display / black. It is possible to provide a liquid crystal cell and a liquid crystal display device in which a difference in color in display is reduced.

Hereinafter, the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.
1. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a color filter in which a plurality of colored domains having different hues are regularly arranged, and a contrast calculated according to the following definition from each of tristimulus values X, Y, and Z in the CIE color space. The present invention relates to a color filter characterized in that CX, CY and CZ satisfy CY <CX <CZ. Here, the CIE color space is a standardized color space that expresses a visible light spectrum established by CIE in 1931. As a basic model of the CIE color space, there is a CIE XYZ color coordinate system. In the present invention, the contrasts CX, CY and CZ of the color filter are obtained from the tristimulus values X, Y and Z in the CIE color space according to the following definitions.

  In FIG. 1, the schematic model of the outline of the measuring method of tristimulus values X, Y, and Z is shown. As shown in FIG. 1, the sample 10 is disposed between a pair of polarizing plates 12a and 12b. Here, the sample 10 becomes a color filter. The light source 14 arranged at the lower part of the polarizing plate 12b is irradiated with light in a planar shape, and the luminance is measured by the luminance meter 16 arranged at the upper part of the polarizing plate 12a. From the measured values, the tristimulus values X, Y And Z are calculated. The respective contrasts of the tristimulus values XYZ are determined by setting the polarizing plates 12a and 12b in the parallel Nicol state (white state) with respect to the tristimulus values Xc, Yc and Zc measured with the polarizing plates 12a and 12b in the crossed Nicols state (black state). Can be defined as the ratio of the tristimulus values Xp, Yp and Zp measured as (ie, Xp / Xc, Yp / Yc and Zp / Zc), but the contributions of the polarizing plates 12a and 12b need to be corrected. Therefore, in the state of FIG. 1 where the sample 10 which is a color filter is arranged, the tristimulus values Xp1, Yp1 and Zp1 are measured with the pair of polarizing plates 12a and 12b in the parallel Nicol state, and the color filter is also arranged. In the state of 1, the tristimulus values Xc1, Yc1, and Zc1 are measured as a crossed Nicol state, and the pair of polarizing plates 12a and 12b are placed in a parallel Nicol state in the state of FIG. The tristimulus values Xp2, Yp2 and Zp2 are measured as follows, and the tristimulus values Xc2, Yc2 and Zc2 are measured as a crossed Nicol state in the state of FIG.

1 and 2, SR-3, BM-5A, etc. manufactured by Topcon Corporation can be used as the luminance meter 16, and the light source 14 includes a fluorescent lamp, a reflector, a diffuser, and a prism sheet. However, the present invention is not limited to this, and the brightness of the same performance as these products can be used. Either a meter or a light source could be used. The pair of polarizing plates 12a and 12b has an extinction ratio of 10 ³ or more at a wavelength of 530 nm, a transmittance in the parallel Nicol state of 5 to 40%, and a transmittance in the crossed Nicol state of 0.00001 to 0.04%. Can be used. An example is a pair of polarizing plates having an extinction ratio of 10 ⁴ or more at a wavelength of 530 nm and a transmittance of 35% in a parallel Nicol state and a transmittance of 0.0035% in a crossed Nicol state. The size of the pair of polarizing plates 12a and 12b is about 10 to 150 mm for the long side, about 10 to 150 mm for the short side, and about 0.1 to 5 mm for the thickness, and the size of the color filter sample is 30 for the long side. Although it is about ˜1500 mm, the short side is about 30 to 1000 mm, and the thickness is about 0.1 to 10 mm, it is not particularly limited to this size.

  Further, as shown in FIGS. 1 and 2, the sample 10 is brought into contact with the polarizing plate 12b arranged on the light source side, and is arranged at a distance of about 50 mm from the polarizing plate 12a arranged on the luminance meter side. Moreover, the broken line in a figure shows the range of a taking-in angle. Here, the capture angle refers to an angle at which the lens opening is viewed from the observation point. The take-in angle is preferably about 0.01 to 10.0 °.

  Here, the contrast C of the aggregate composed of n (n is a natural number) contrast lowering factors is defined by the following model expression using the contrast Ci (1 ≦ i ≦ n) of each factor.

The ratios of the tristimulus values of the parallel Nicol state and the crossed Nicol state obtained in the state of FIG. 1, Xp1 / Xc1, Yp1 / Yc1, and Zp1 / Zc1, respectively, are the contrast of the aggregate of the color filter and the polarizing plate, Further, since the ratios of the tristimulus values of the parallel Nicol state and the crossed Nicol state obtained in the state of FIG. 2, Xp2 / Xc2, Yp2 / Yc2, and Zp2 / Zc2 are respectively the contrast of the polarizing plate alone, the color filter alone The contrasts CX, CY, and CZ are respectively defined by the following equations.
1 / CX = Xc1 / Xp1-Xc2 / Xp2
1 / CY = Yc1 / Yp1-Yc2 / Yp2
1 / CZ = Zc1 / Zp1-Zc2 / Zp2

  In the color filter of the present invention, the contrasts CX, CY and CZ defined as described above calculated from the tristimulus values X, Y and Z satisfy CY <CX <CZ. As a result of intensive studies by the present inventors, VA (vertical alignment) mode, IPS (in-plane switching) mode, TN (twisted nematic) mode, STN (super twisted nematic) mode, ECB (electrically controlled birefringence) mode, and OCB It has been found that in any liquid crystal mode having different modes of operation such as (optically compensated bend) mode, blue light leakage may occur in the liquid crystal layer during black display. Therefore, it was found that the contrasts CX, CY and CZ of the liquid crystal layer alone are reduced by the blue leakage light generated during black display, and CZ <CX <CY. Further, with respect to a general polarizing plate, the contrast CX, CY and CZ of the polarizing plate alone satisfies CZ <CX <CY. By using the color filter of the present invention that satisfies the above characteristics, it is possible to compensate for the decrease in contrast CZ caused by the liquid crystal layer and the polarizing plate. As the liquid crystal cell and the liquid crystal display device as a whole, CX, CY and CZ Are approximately equal, that is, it is possible to reduce the coloring with black display.

  Among the color filters of the present invention, the aspect in which the contrasts CZ and CY satisfy 3 × CY <CZ is excellent in that the coloring produced in a high-contrast liquid crystal cell can be reduced. More preferably, 5 × CY ≦ CZ. Although the effects of the present invention can be obtained as long as the contrast CX, CY, and CZ of the color filter of the present invention satisfies CY <CX <CZ, from the viewpoint of contributing to high image quality, high contrast, etc. of the liquid crystal display device. Assuming that CY <CX <CZ is satisfied, CX is 2000 to 40000, CY is 1500 to 30000, and CZ is preferably 3000 to 200000, and CX is 5000 to 40000. , CY is 4000-30000, and CZ is more preferably 20000-200000.

Hereinafter, materials and methods used for manufacturing the color filter of the present invention will be described in detail.
An example of the color filter of the present invention is an RGB color filter including a red (R) domain, a green (G) domain, and a blue (B) domain, or an RGBW color filter including a white (W) domain together with the RGB domain. Hereinafter, a manufacturing method, materials used, and the like are mainly described as examples of color filters including an RGB domain, but the color filter of the present invention is not limited to this mode.
In the manufacture of the color filter of the present embodiment, each domain can be formed using a coloring composition of each color of RBG. A color filter satisfying CY <CX <CZ can be manufactured by adjusting the composition of the coloring composition that is the raw material of each of the R domain, the G domain, and the B domain. Specifically, each of the coloring compositions that are the raw materials of each of the R domain, G domain, and B domain is separately applied to glass with the same thickness to form an R layer, a G layer, and a B layer. When the contrasts CYR, CYG, and CYB of the stimulus value Y in each CIE color space are calculated, each coloring composition is prepared so as to satisfy CYG <CYR <CYB. In particular, when the contrast CYG and CYB of the G layer and the B layer satisfy CYG × 4 ≦ CYB, it is preferable in terms of reducing tinting that occurs in a high-contrast liquid crystal cell. More preferably, CYG × 10 ≦ CYB.

The coloring composition used to form each colored domain contains colorants such as dyes and pigments.
Pigment:
As a pigment used as a colorant such as RGB, both inorganic pigments and organic pigments can be used. As the average particle diameter of the pigment is smaller, the colored domain formed from the coloring composition containing the pigment tends to have higher contrast. Accordingly, in an embodiment in which a coloring composition containing one or more pigments is used to form each of the R domain, the G domain, and the B domain, each of the main pigments of the R domain, the G domain, and the B domain is used. Average particle diameter dr (average particle diameter of main pigment in R domain), dg (average particle diameter of main pigment in G domain) and db (average particle diameter of main pigment in B domain) satisfy db <dr <dg It is preferable to do. Here, the “main pigment” refers to a pigment contained in the highest ratio among all the pigments contained in the colored composition. The “average particle size” of the pigment is a value measured by drying the pigment dispersion on a filter paper, taking a scanning electron micrograph, and measuring 100 particles with a caliper. This average particle size is sometimes referred to as the primary particle size. Generally, the average particle diameter of the pigment used for forming the color filter is about 5 to 50 nm. As an example, on the condition that db <dr <dg is satisfied, the average particle size dr of the R domain main pigment is about 15 to 50 nm, the average particle size dg of the G domain main pigment is about 15 to 50 nm, and The average particle size db of the B domain main pigment is about 5 to 35 nm.

  Moreover, there is a tendency that the colored domain formed from the colored composition containing the pigment has a higher contrast as the aggregation degree of the pigment is smaller. Accordingly, in an embodiment in which a coloring composition containing one or more pigments is used to form each of the R domain, the G domain, and the B domain, each of the main pigments of the R domain, the G domain, and the B domain is used. Aggregation degree fr (aggregation degree of main pigment in R domain), dg (aggregation degree of main pigment in G domain) and db (aggregation degree of main pigment in B domain) preferably satisfy fb <fr <fg. . Here, the “aggregation degree” refers to the average number of pigment particles forming the aggregate. For example, the number average particle size of aggregated particles (when called the secondary particle size using Nanotrac UPA-EX150 manufactured by Nikkiso Co., Ltd.) And the degree of aggregation can be measured by dividing the measured value by the primary particle size obtained from an electron micrograph. Generally, the aggregation degree of the pigment used for forming the color filter is about 1.0 to 10.0. As an example, on the condition that fb <fr <fg is satisfied, the aggregation degree fr of the main pigment in the R domain is about 1.0 to 2.5, and the aggregation degree fg of the main pigment in the G domain is 1.0 to 2.5. About 3.5 and the aggregation degree fb of the main pigment of the B domain is about 1.0 to 2.0.

  In consideration of both characteristics, in an embodiment in which each of the G domain and the B domain contains one or more pigments, the average particle diameters dg and db of the main pigments in the G domain and the B domain, and the G domain And the cohesion degrees fg and fb of the main pigments in the B domain preferably satisfy dg × fg> 1.5 × db × fb.

  Methods for controlling the average particle diameter and the degree of aggregation of the pigment include a breakdown method in which the pigment is crushed into fine particles, and a build-up method in which the fine particles are formed when the pigment is synthesized from the molecular level. Regardless of which method is used, a pigment satisfying the above conditions can be prepared. The breakdown method is a method in which the pigment is pulverized by a pulverizer such as a bead mill or a roll mill to adjust the average particle size and the like, and the pigment is pulverized together with a dispersant and a solvent as desired. On the other hand, the build-up method is a method of preparing a dispersion liquid of an organic pigment by adding a poor solvent of the raw material to a solution in which the raw material of the organic pigment is dissolved. The build-up method has a more uniform and fine particle size than the breakdown method. There is a feature that an organic pigment is obtained. Details of the building and up method are described in various documents, such as JP 2007-197566, JP 2007-262378, and JP 2007-321110. Can be referred to. Examples of pigments that can be used in the present invention include pigment examples described in the above three publications, as well as JP 2008-134613 A, JP 2008-83089 A, and JP Examples of pigments described in JP-A-2008-88272 and the like are included.

dye:
A dye can be used as the colorant. Also in the embodiment using the dye, each of the colored compositions as the raw materials of the R domain, G domain, and B domain is separately coated on the glass with the same thickness, and the R layer, the G layer, and the B layer are formed. Each coloring composition is prepared so that the contrasts CYR, CYG and CYB of the stimulus value Y in each CIE color space satisfy CYG <CYR <CYB. In particular, it is preferable that the formula CYG × 4 ≦ CYB is satisfied, as in the case of using a pigment. In general, a colored composition colored with a dye tends to have a higher contrast than a colored composition colored with a pigment. Therefore, if the colored composition used for forming the B domain is a composition colored with a dye, it will be easy to prepare each colored composition satisfying the above formula. An example is an embodiment in which the R domain and the G domain are each composed of a colored composition colored with a pigment, and the B domain is composed of a colored composition colored with a dye.

  There is no particular limitation on the dye that can be used in the present invention. Examples of the dyes described in the patent publications and the like referred to in the description of the pigment can also be used for producing the color filter of the present invention.

  The content of the colorant in the coloring composition also affects the contrast of each colored domain. Generally, in the total solid content of the coloring composition, the content of the colorant is about 20 to 50% by mass, and when using a pigment, the content is 25 to 35% by mass. When the dye is used, its content is preferably 25 to 45% by mass, and is determined so as to satisfy the above conditions.

Photosensitive component:
The colored composition used for forming each colored domain of the color filter of the present invention is preferably photosensitive. When photosensitive, a plurality of regularly arranged colored domains can be formed by performing an exposure step through a photomask and a subsequent development step. The photosensitive coloring composition may be a positive type or a negative type. An example of the photosensitive coloring composition includes (1) an alkali-soluble resin, (2) a monomer or an oligomer, and (3) a photopolymerization initiator or a photopolymerization initiator system as a photosensitive component together with the colorant. including.

(1) Alkali-soluble resin The alkali-soluble resin (hereinafter sometimes simply referred to as “binder”) is preferably a polymer having a polar group such as a carboxylic acid group or a carboxylic acid group in the side chain. Examples thereof include JP-A-59-44615, JP-B-54-34327, JP-B-58-12577, JP-B-54-25957, JP-A-59-53836, and JP-A-57-36. A methacrylic acid copolymer, an acrylic acid copolymer, an itaconic acid copolymer, a crotonic acid copolymer, a maleic acid copolymer, a partially esterified maleic acid copolymer as described in JP-A-59-71048 Etc. Moreover, the cellulose derivative which has a carboxylic acid group in a side chain can also be mentioned, In addition to this, what added the cyclic acid anhydride to the polymer which has a hydroxyl group can also be used preferably. Further, as particularly preferred examples, copolymers of benzyl (meth) acrylate and (meth) acrylic acid described in US Pat. No. 4,139,391, benzyl (meth) acrylate, (meth) acrylic acid and other monomers And a multi-component copolymer. The binder polymer having these polar groups may be used alone, or may be used in the state of a composition used in combination with an ordinary film-forming polymer, and the content of the colored composition with respect to the total solid content is 20-50 mass% is common and about 25-45 mass% is preferable.

(2) Monomer or oligomer The monomer or oligomer is preferably a monomer or oligomer that has two or more ethylenically unsaturated double bonds and undergoes addition polymerization upon irradiation with light. Examples of such monomers and oligomers include compounds having at least one addition-polymerizable ethylenically unsaturated group in the molecule and having a boiling point of 100 ° C. or higher at normal pressure. Examples include monofunctional acrylates and monofunctional methacrylates such as polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate and phenoxyethyl (meth) acrylate; polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) ) Acrylate, trimethylolethane triacrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane diacrylate, neopentyl glycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, di Pentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, hexane All di (meth) acrylate, trimethylolpropane tri (acryloyloxypropyl) ether, tri (acryloyloxyethyl) isocyanurate, tri (acryloyloxyethyl) cyanurate, glycerin tri (meth) acrylate; multifunctional such as trimethylolpropane and glycerin Polyfunctional acrylates and polyfunctional methacrylates such as those obtained by adding ethylene oxide or propylene oxide to alcohol and then (meth) acrylated can be mentioned.
Further, urethane acrylates described in JP-B-48-41708, JP-B-50-6034 and JP-A-51-37193; JP-A-48-64183, JP-B-49-43191 And polyester acrylates described in Japanese Patent Publication No. 52-30490; polyfunctional acrylates and methacrylates such as epoxy acrylates which are reaction products of epoxy resin and (meth) acrylic acid. Among these, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and dipentaerythritol penta (meth) acrylate are preferable.
In addition, “polymerizable compound B” described in JP-A-11-133600 can also be mentioned as a preferable example.
These monomers or oligomers may be used alone or in admixture of two or more kinds, and the content of the colored composition with respect to the total solid content is generally 5 to 50% by mass, and about 10 to 40% by mass Is preferred.

(3) Photopolymerization initiator or photopolymerization initiator system Examples of the photopolymerization initiator or photopolymerization initiator system include vicinal polyketaldonyl compounds disclosed in US Pat. No. 2,367,660, US Pat. No. 2,448,828. The acyloin ether compounds described in U.S. Pat. No. 2,722,512 and the aromatic acyloin compounds substituted with α-hydrocarbons described in U.S. Pat. No. 2,722,512, U.S. Pat. Nos. 3,046,127 and 2,951,758. A polynuclear quinone compound described in US Pat. No. 3,549,367, a combination of a triarylimidazole dimer and a p-aminoketone, a benzothiazole compound described in Japanese Patent Publication No. 51-48516, and a trihalomethyl-s-triazine Compound, trihalomethy described in US Pat. No. 4,239,850 - it can be exemplified triazine compounds, U.S. Patent trihalomethyl oxadiazole compounds described in No. 4,212,976 specification or the like. In particular, trihalomethyl-s-triazine, trihalomethyloxadiazole, and triarylimidazole dimer are preferable.
These photopolymerization initiators or photopolymerization initiator systems may be used singly or as a mixture of two or more, but it is particularly preferable to use two or more. When at least two kinds of photopolymerization initiators are used, display characteristics, particularly display unevenness, can be reduced.
The content of the photopolymerization initiator or the photopolymerization initiator system with respect to the total solid content of the colored composition is generally 0.5 to 20% by mass, and preferably 1 to 15% by mass.

  In addition, other additives such as a sensitizer, a sympathizer, a dispersant, and a surfactant may be added to the photosensitive coloring composition. The photosensitive coloring composition can be prepared as a coating solution dispersed and / or dissolved in a solvent. As for these other additives and the solvent used for preparing the coating liquid, the description in the published publication referred to in the description of the pigment can be referred to.

  A method for producing a color filter using the photosensitive coloring composition is as follows. First, a coloring composition of any hue is applied to the surface of a substrate to form a coating film, and then light is irradiated imagewise through a photomask. In the light irradiation part, polymerization of the photosensitive component proceeds and is cured. On the other hand, polymerization of the photosensitive component does not proceed in the unexposed area. When developing with an alkaline developer in this state, the unexposed portion is dissolved and removed in the developer, while the exposed portion is cured by polymerization and remains imagewise on the substrate. As a result, an image of the first color domain is formed on the substrate. By repeating this operation three times to form the R, G, and B domains, a color filter having RGB domains can be formed on the substrate.

  The said method is an example and is not limited to the said method. For example, when the ink jet method is used, a developing step is not necessary, and a material added for providing developability is not necessary. In addition, it can also be manufactured by a transfer method using a transfer material.

  The thickness of each colored domain is preferably equal to each other in order to maintain surface smoothness. The thickness of each colored domain of the color filter is generally about 0.5 to 5.0 μm, and the thickness of each colored domain of the color filter of the present invention is also preferably in the above range.

  The color filter of the present invention preferably has a substrate that supports each colored domain. The substrate is, for example, a substrate made of alkali-free glass, soda glass, Pyrex (registered trademark) glass, quartz glass, or the like used for a liquid crystal display element; a substrate in which a transparent conductive film is laminated; a solid-state imaging device or the like Examples include a photoelectric conversion element substrate; a silicon substrate; and a plastic substrate. The plastic substrate preferably has a gas barrier layer and / or a solvent resistant layer on its surface. The substrate is preferably light transmissive in the visible light region, and preferably has a transmittance of 90% or more.

  Also, on these substrates, a black matrix that normally separates the domains is formed. The black matrix can be formed in the same manner as each colored domain. Specifically, pattern exposure and development are performed using a photosensitive black composition using a black pigment such as carbon black or titanium black as a pigment, and then post-baking is further promoted as necessary to promote film curing. Can be formed.

2. TECHNICAL FIELD The present invention also relates to a liquid crystal cell and a liquid crystal display device having the color filter of the present invention. An example of the liquid crystal cell of the present invention is a liquid crystal cell having a pair of substrates and a liquid crystal layer disposed between the substrates, and one of the pair of substrates is the color filter of the present invention. The color filter of the present invention used in the liquid crystal cell of this aspect preferably has a glass substrate or the like that serves as a cell substrate. The color filter of the present invention is preferably disposed on the display surface side with respect to the liquid crystal layer.

  The liquid crystal cell of the present invention may use any liquid crystal mode such as VA mode, IPS mode, TN mode, STN mode, ECB mode, and OCB mode. In the liquid crystal cell of the present invention, the blue contrast CZ is lower than the red and green contrasts CX and CY due to the blue light leakage from the liquid crystal layer when displaying black. This problem is solved by incorporating the color filter of the present invention in the liquid crystal cell. Therefore, the characteristics of CX, CY, and CZ are approximately equal for the entire liquid crystal cell. More specifically, the liquid crystal cell of the present invention is characterized in that the contrasts CX, CY and CZ calculated from the respective stimulus values X, Y and Z in the CIE color space are equal to each other within a range of 10% error. And Here, “equal within an error range of 10%” means that each of CX, CY, and CZ is CA ± 10% with respect to the average value CA.

As a method for measuring the contrast CX, CY, and CZ of the liquid crystal cell, first, as shown in FIG. 1, a liquid crystal cell having the color filter of the present invention is arranged as a sample 10 between a pair of polarizing plates 12a and 12b. To do. The light source 14 arranged at the lower part of the polarizing plate 12b is irradiated with light in a planar shape, and the luminance is measured by the luminance meter 16 arranged at the upper part of the polarizing plate 12a. From the measured values, the tristimulus values X, Y And Z are calculated. The respective contrasts of the tristimulus values XYZ are measured by setting the polarizing plates 12a and 12b in the crossed Nicols state (black state) and the polarizing plates 12a and 12b in the parallel Nicol state (white state) relative to the tristimulus values Xc1, Yc1 and Zc1 As the ratio of tristimulus values Xp1, Yp1 and Zp1 measured as (ie, Xp1 / Xc1, Yp1 / Yc1 and Zp1 / Zc1).
1 / CX = Xc1 / Xp1
1 / CY = Yc1 / Yp1
1 / CZ = Zc1 / Zp1

  From the viewpoint of high image quality and high contrast, the CY of the liquid crystal cell is preferably 5000 or more, and more preferably 8000 or more. Similarly, CZ and CX are also preferably in the above range.

The color of white display and black display of the liquid crystal cell can be expressed using the chromaticity value xy. As a measuring method of the chromaticity value xy, first, as shown in FIG. 1, a liquid crystal cell having the color filter of the present invention is placed between a pair of polarizing plates 12a and 12b as shown in FIG. Deploy. The light source 14 arranged at the lower part of the polarizing plate 12b is irradiated with light in a planar shape, and the luminance is measured by the luminance meter 16 arranged at the upper part of the polarizing plate 12a. From the measured values, the tristimulus values X, Y And Z are calculated. The chromaticity value xy can be defined by the following equation using the tristimulus values XYZ.
x = X / (X + Y + Z)
y = Y / (X + Y + Z)

  In the liquid crystal display device of the present invention, since the color filter of the present invention is arranged in the liquid crystal cell, the decrease in contrast of a predetermined hue caused by each of the liquid crystal layer, the polarizer, and the color filter cancels each other. Therefore, there is little tinting in both white display and black display, and the color shift between white display and black display is small. As an example, in the VA mode liquid crystal display device, the xy chromaticity values at the time of white display are x = 0.29 and y = 0.29, respectively, and the respective differences between the stimulus values x and y at the time of white display and black display Of 0.01 or less can be achieved.

The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. Unless otherwise specified, “part” means “part by mass”.
In the following examples, the contrasts CX, CY, and CZ of each member are the values calculated from the stimulation values X, Y, and Z obtained by the above-described method, that is, the measurements shown in FIGS. is there. As the light source 14 in FIGS. 1 and 2, a three-wavelength cold cathode tube light source (FWL18EX-N manufactured by Toshiba Lighting & Technology Co., Ltd.) and a BM-5A manufactured by Topcon Corporation as the luminance meter 16 are used. did. As the polarizing plates 12a and 12b, polarizing plates having an extinction ratio of 10 ⁴ , a parallel Nicol state transmittance of 35%, and a crossed Nicol state transmittance of 0.0035% were used.

(Preparation of photosensitive red compositions 1-12)
-Red composition A-Dispersion / pigment: Pigment Red 254 (average particle size, aggregation degree is listed in Table 1) 11 partsPigment: Pigment Red 177 (average particle diameter 18 nm, aggregation degree 1.1) 4 parts / dispersion Agent (trade name: Disperbyk-161, manufactured by Big Chemie; mixed solvent of methoxybutyl acetate and butyl acetate) 3 parts, alkali-soluble resin: benzyl methacrylate / methacrylic acid copolymer = 75/25 [mass ratio] copolymer , Weight average molecular weight Mw: 5000) propylene glycol monomethyl ether acetate solution (solid content: 50% by mass) 14 parts (B) Dispersing resin dissolving solvent: propylene glycol monomethyl ether acetate (SP value 9.2, boiling point 146 ° C. 73 parts

-Red composition B-Coating liquid-Red composition A dispersion 100 parts-Epoxy resin: (trade name EHPE3150, manufactured by Daicel Chemical) 2 parts-Polymerizable compound: Dipentaerythritol penta-hexaacrylate 8 parts-Polymerization initiator: 4 -(O-bromo-pN, N-di (ethoxycarbonylmethyl) amino-phenyl) -2,6-di (trichloromethyl) -s-triazine 1 part-polymerization initiator: 2-benzyl-2-dimethyl Amino-1- (4-morpholinophenyl) -butanone-1 1 part ・ Initiator: Diethylthioxanthone 0.5 part ・ Polymerization inhibitor: p-methoxyphenol 0.001 part ・ Fluorosurfactant: (Product Name: Megafac R30 manufactured by Dainippon Ink)
0.01 parts-Nonionic surfactant: (trade name: Tetronic R150, manufactured by ADEKA) 0.2 parts-(A) High boiling point solvent: 1,3 butylene glycol diacetate (boiling point 232 ° C) 50 parts-(B ) Dispersing resin dissolving solvent: propylene glycol monomethyl ether acetate (SP value 9.2, boiling point 146 ° C.) 80 parts The above red composition B was mixed and stirred to obtain a coating liquid of a curable coloring composition.
In addition, Table 1 shows the average particle diameter dr and the aggregation degree fr of R pigment: Pigment Red 254 (main pigment) used for the preparation of the prepared photosensitive red compositions 1-12.

(Preparation of photosensitive green compositions 1-12)
-Green Composition A-Dispersion / Pigment: Pigment Green 36 (average particle size, aggregation degree is listed in Table 2) 11 partsPigment: Pigment Yellow 150 (average particle diameter 22 nm, aggregation degree 1.1) 7 parts Dispersant (Product name: Disperbyk-161, 30% solution manufactured by Big Chemie) 3 parts of alkali-soluble resin: benzyl methacrylate / methacrylic acid copolymer = 75/25 [mass ratio] copolymer, weight average molecular weight Mw: 5000) Propylene glycol monomethyl ether acetate solution (solid content: 50% by mass) 14 parts · (B) Dispersing resin dissolving solvent: methyl 3-ethoxypropionate (SP value 9.3, boiling point 165 ° C) 70 parts

-Green composition B-Coating liquid-Green composition A dispersion 100 parts-Epoxy resin: (trade name EHPE3150, manufactured by Daicel Chemical) 2 parts-Polymerizable compound: Dipentaerythritol penta-hexaacrylate 8 parts-Polymerization initiator: 1 , 3-bistrihalomethyl-5-benzooxolantolyazine 2 parts, polymerization initiator: 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 1 part, polymerization initiator: diethyl Thioxanthone 0.5 parts, Polymerization inhibitor: p-methoxyphenol 0.001 part, Fluorosurfactant (trade name: Megafac R08, manufactured by Dainippon Ink) 0.02 parts, Nonionic surfactant (trade name: Emulgen A-60 Kao) 0.5 part ・ (A) High boiling point solvent: 1,3 Butylene glycol diacetate (boiling point 232 ° C.) 0 parts / (B) Dissolving resin dissolving solvent: methyl 3-ethoxypropionate (SP value 9.3, boiling point 165 ° C.) 100 parts The green composition B is mixed and stirred to obtain a coating liquid of the curable coloring composition. It was.
Table 2 below shows the average particle diameter dg and the aggregation degree fg of G pigment: Pigment Green 36 (main pigment) used for the preparation of the prepared photosensitive green compositions 1-12.

(Preparation of photosensitive blue compositions 1-11)
-Blue composition A-Dispersion / pigment: Pigment Blue 15: 6 (average particle size, aggregation degree is listed in Table 3) 14 partsPigment: Pigment Violet 23 (average particle size 23 nm in SEM observation, aggregation degree 1. 1) 1 part Dispersant: (Brand name: Disperbyk-161, 30% solution manufactured by Big Chemie)
3 parts, alkali-soluble resin: benzyl methacrylate / methacrylic acid copolymer = 75/25 [mass ratio] copolymer, weight average molecular weight Mw: 5000) propylene glycol monomethyl ether acetate solution (solid content: 50 mass%) 14 Parts / (B) Solvent for dissolving dispersed resin: propylene glycol monomethyl ether acetate (SP value 9.2, boiling point 146 ° C.) 73 parts

-Blue composition B-Coating solution-Blue component A dispersion 100 parts-Alkali-soluble resin: benzyl methacrylate / methacrylic acid copolymer = 75/25 [mass ratio] copolymer, weight average molecular weight Mw: 5000) propylene Glycol monomethyl ether acetate solution (solid content: 50% by mass) 6 parts, epoxy resin: (trade name EHPE3150, manufactured by Daicel Chemical) 2 parts, UV curable resin: (trade name, Cyclomer P ACA-250, manufactured by Daicel Chemical) side chain 4 parts propylene glycol monomethyl ether acetate solution of acrylic copolymer containing alicyclic ring, COOH group and acryloyl group (solid content: 50% by mass) Polymerizable compound: 12 parts dipentaerythritol pentahexaacrylate Polymerization start Agent: 1- (9-ethyl-6- (2-methylbenzoyl)- H-carbazol-3-yl) -1- (O-acetyloxime) ethanone 3 parts, polymerization inhibitor: p-methoxyphenol 0.001 part, fluorine-based surfactant: (trade name: Megafac R08, manufactured by Dainippon Ink ) 0.02 part ・ Nonionic surfactant: (Product name: Emulgen A-60 manufactured by Kao) 1.0 part ・ (A) High boiling point solvent: Propylene glycol n-butyl ether acetate (boiling point 211 ° C.) 20 parts ( B) Dispersing resin dissolving solvent: propylene glycol monomethyl ether acetate (SP value 9.2, boiling point 146 ° C.) 150 parts The blue composition B was mixed and stirred to obtain a coating solution of a curable coloring composition.
In addition, Table 3 shows the average particle diameter db and the aggregation degree fb of B pigment: Pigment Blue 15: 6 (main pigment) used for the preparation of the prepared photosensitive green compositions 1-12.

(Preparation of photosensitive blue composition 21)
-Blue composition C-Dispersion / dye: C.I. I. Acid Blue 86 14 parts Dispersant: (Product name: Disperbyk-161, 30% solution manufactured by Big Chemie)
3 parts, alkali-soluble resin: benzyl methacrylate / methacrylic acid copolymer = 75/25 [mass ratio] copolymer, weight average molecular weight Mw: 5000) propylene glycol monomethyl ether acetate solution (solid content: 50 mass%) 14 Parts / (B) Solvent for dissolving dispersed resin: propylene glycol monomethyl ether acetate (SP value 9.2, boiling point 146 ° C.) 73 parts

-Blue composition D-Dispersion solution of coating composition-Blue composition C 100 parts-Alkali-soluble resin: benzyl methacrylate / methacrylic acid copolymer = 75/25 [mass ratio] copolymer, weight average molecular weight Mw: 5000) propylene Glycol monomethyl ether acetate solution (solid content: 50% by mass) 6 parts, epoxy resin: (trade name EHPE3150, manufactured by Daicel Chemical) 2 parts, UV curable resin: (trade name, Cyclomer P ACA-250, manufactured by Daicel Chemical) side chain Acrylic copolymer containing alicyclic ring, COOH group, and acryloyl group Propylene glycol monomethyl ether acetate solution (solid content: 50% by mass) 4 parts Polymerizable compound: 12 parts dipentaerythritol pentahexaacrylate Polymerization initiator : 1- (9-ethyl-6- (2-methylbenzoyl) -9 -Carbazol-3-yl) -1- (O-acetyloxime) ethanone 3 parts ・ Polymerization inhibitor: p-methoxyphenol 0.001 part ・ Fluorosurfactant: (trade name: Megafac R08, manufactured by Dainippon Ink) 0.02 parts-Nonionic surfactant: (trade name: Emulgen A-60 manufactured by Kao) 1.0 parts-(A) High boiling point solvent: Propylene glycol n-butyl ether acetate (boiling point 211 ° C)
20 parts / (B) Dissolving solvent for disperse resin: propylene glycol monomethyl ether acetate (SP value 9.2, boiling point 146 ° C.) 150 parts The blue composition D was mixed and stirred to obtain a coating solution of a curable coloring composition. .

(Preparation of Example Color Filters 1 to 6 and Comparative Example Color Filters 11 to 19)
Any one of the prepared photosensitive red compositions 1 to 12, any one of the prepared photosensitive green compositions 1 to 12, and any of the prepared photosensitive blue compositions 1 to 11 and 21 A color filter was prepared using one of these. Specifically, a color filter was produced by combining the photosensitive coloring compositions shown in Table 4 below.
Prepare a glass substrate having a black matrix on the surface, apply a colored composition of any of the three colors to the surface, irradiate it with a photomask imagewise, and then develop it with an alkaline developer. Then, the non-light-irradiated portion was removed, and the colored domains regularly arranged on the substrate were formed. This operation was also performed for the other two photosensitive coloring compositions. In this manner, the RGB color filters for Examples 1 to 6 and the RGB color filters for comparative examples 11 to 19 were produced, respectively.

  The following table shows the values of CX, CY and CZ calculated by the above method for the produced color filter. Furthermore, the photosensitive red composition, the photosensitive green composition and the photosensitive blue composition used for the production of each color filter were each coated on a glass substrate and cured to obtain an R layer having a thickness of 2.0 μm. , G layer and B layer were formed respectively. Since CYR, CYG, and CYB were obtained by the method described above for each formed G layer and each R layer, the values are also shown in the following table.

  As shown in the above table, the color filters 1 to 6 for the examples all satisfy CY <CX <CZ, and the color filters for the comparative examples 11 to 19 are CX = CY = CZ, or CZ <CX <CY or a color filter of CX <CY <CZ.

(Production of VA mode liquid crystal cells 1 to 15)
Three types of VA modes having general configurations and different degrees of depolarization were prepared. A VA mode liquid crystal cell having a depolarization degree a1 is a liquid crystal cell 1, a VA mode liquid crystal cell having a depolarization degree a2 is a liquid crystal cell 2, and a VA mode liquid crystal cell having a depolarization degree a3 is a liquid crystal cell 3. For any one of these liquid crystal cells 1 to 3, a VA mode liquid crystal cell using one of the above color filters 1 to 6 and the above comparative example color filters 11 to 19 on one of the cell substrates. 1 to 15 were produced.
Contrasts CX, CY and CZ were determined for each of the manufactured liquid crystal cells by the method described above. The results are shown in the table below. In the following table, CX, CY and CZ of the color filter used are also shown.

(Examples 1-6 and Comparative Examples 1-6)
A pair of polarizing plates were placed in a crossed Nicol state, and the liquid crystal cells prepared above were placed between them to prepare VA mode liquid crystal display devices. These liquid crystal display devices were set to a white state and a black state, and stimulus values X, Y, and Z were measured, respectively. Also, the chromaticity value xy and the white / black contrast CY were obtained. The results are shown in the table below.

From the results shown in the above table, it can be understood that CX, CY and CZ are equal to each other in the liquid crystal cells 1 to 6 each including the color filters 1 to 6 of the embodiment of the present invention. As a result, it can be understood that all of the liquid crystal display devices of Examples 1 to 6 each having these have substantially the same chromaticity value xy when displaying white and displaying black.
On the other hand, the liquid crystal cells 7 to 12 using the color filter for comparative example that do not satisfy CY <CX <CZ have different chromaticity values xy during white display and black display, and have a color shift. Can understand.

  In the above, the effect of the embodiment was confirmed for the VA mode liquid crystal display device. However, in other modes, for example, the TN mode, the IPS mode, the OCB mode, and the ECB mode, blue light leakage occurs in the liquid crystal layer. If so, it is expected that the effects of the present invention can be achieved in any case.

It is the schematic diagram used in order to demonstrate the measuring method of the contrast of the color filter and liquid crystal cell of this invention. It is the schematic diagram used for demonstrating the measuring method of the contrast of the color filter of this invention.

Explanation of symbols

10 samples (color filter or liquid crystal cell)
12a, 12b Polarizing plate 14 Light source 16 Luminance meter

Claims (12)

A color filter in which a plurality of colored domains having different hues are regularly arranged, and contrasts CX, CY, and CZ calculated according to the following definitions from tristimulus values X, Y, and Z in the CIE color space are respectively , CY <CX <CZ.
(CX, CY, and CZ of the color filters are respectively prepared as a pair of polarizing plates, and tristimulus values Xp1, Yp1 obtained by irradiating light with the color filter sandwiched between the pair of polarizing plates in a parallel Nicol state. And Zp1; tristimulus values Xc1, Yc1 and Zc1 obtained by irradiating light with the color filter sandwiched between the pair of polarizing plates in the crossed Nicol state; the pair of polarizing plates without the color filter sandwiched in the parallel Nicol state Tristimulus values Xp2, Yp2, and Zp2 obtained by irradiating light and tristimulus values Xc2, Yc2 obtained by irradiating light with the pair of polarizing plates sandwiching no color filter in a crossed Nicol state Zc2; and the following formula 1 / CX = Xc1 / Xp1-Xc2 / Xp2
1 / CY = Yc1 / Yp1-Yc2 / Yp2
1 / CZ = Zc1 / Zp1-Zc2 / Zp2
Respectively. ) The color filter according to claim 1, wherein 3 × CY <CZ is satisfied. The color filter according to claim 1, wherein the plurality of colored domains having different hues include a red (R) domain, a green (G) domain, and a blue (B) domain. It is calculated from the stimulus value Y in the CIE color space of each of the G layer and the B layer formed by separately applying the colored composition, which is the raw material of each of the G domain and B domain, onto the glass with the same thickness. 4. The color filter according to claim 1, wherein the contrasts CYG and CYB satisfy CYG × 4 ≦ CYB. 5. Each of the R domain, the G domain, and the B domain contains one or more pigments, and the average particle diameters dr, dg, and db of each of the main pigments in the R domain, the G domain, and the B domain are db <dr 5. The color filter according to claim 1, wherein <dg is satisfied and dg> 1.5 × db is satisfied. Each of the R domain, the G domain, and the B domain contains one or more pigments, and the degree of aggregation fr, fg, and fb of each of the main pigments in the R domain, the G domain, and the B domain is fb <fr The color filter according to claim 1, wherein <fg is satisfied and fg> 1.5 × fb is satisfied. The G domain and the B domain each contain one or more pigments, the average particle diameters dg and db of the main pigments in the G domain and the B domain, respectively, and the aggregation degree of each of the main pigments in the G domain and the B domain The color filter according to claim 1, wherein fg and fb satisfy dg × fg> 1.5 × db × fb. The R domain and the G domain are each colored with one or more pigments, and the B domain is colored with one or two or more dyes. Color filter. A liquid crystal cell having the color filter according to any one of claims 1 to 8, wherein the contrasts CX and CY are calculated according to the following definitions from the respective stimulus values X, Y and Z in the CIE color space. And CZ are equal to each other within an error of 10%.
(CX, CY and CZ of the liquid crystal cell are respectively prepared as a pair of polarizing plates, and tristimulus values Xp1, Yp1 obtained by irradiating light in a state where the liquid crystal cell is sandwiched between the pair of polarizing plates in a parallel Nicol state. And Zp1; and the tristimulus values Xc1, Yc1, and Zc1 obtained by irradiating light with the liquid crystal cell sandwiched between the pair of polarizing plates in the crossed Nicols state, the following formula 1 / CX = Xc1 / Xp1
1 / CY = Yc1 / Yp1
1 / CZ = Zc1 / Zp1
Respectively. ) The liquid crystal cell according to claim 9, wherein the liquid crystal cell is in a vertical alignment mode. CY is 5000 or more, The liquid crystal cell of Claim 9 or 10 characterized by the above-mentioned. The liquid crystal display device which has a pair of polarizer and the liquid crystal cell of any one of Claims 9-11 arrange | positioned between them.

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