JP2005092054A - Color filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color filter for obtaining a highly reliable liquid crystal display device which is excellent in surface smoothness and which can reduce residual charges and with which an image persistence is not generated on a screen of the liquid crystal display even when the device performs a long-term displaying on the screen. <P>SOLUTION: This color filter is equipped with a transparent substrate and a colored layer provided on the transparent substrate but not equipped with an electrode. The color filter is characterized in that the colored layer is coated with a conductive overcoat layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a color filter used in a color liquid crystal display device, and more particularly to a color filter that reduces residual charges.

  In a liquid crystal display device, a display side substrate such as a color filter and a liquid crystal driving side substrate are opposed to each other, and a liquid crystal compound is sealed between them to form a thin liquid crystal layer. The liquid crystal driving side substrate forms a liquid crystal array in the liquid crystal layer. The display is performed by electrically changing the amount of light transmitted or reflected by the display-side substrate.

  There are various driving methods such as a static driving method, a simple matrix method, and an active matrix method, but in recent years, one method for improving the narrowness of the viewing angle is disclosed in Japanese Patent Application Laid-Open No. 7-159786. In-plane switching (IPS), in which the liquid crystal sandwiched between the TFT array substrate and the color filter is driven by a parallel electric field between the pixel electrode and the common electrode provided on the array substrate. A mode has been proposed. In the IPS color liquid crystal display device, since the liquid crystal is horizontally aligned, the birefringence of the liquid crystal is not involved in the display characteristics, and a wide viewing angle can be achieved.

  FIG. 1 conceptually shows a difference in liquid crystal driving between the TN system using a vertical electric field and the IPS system using a parallel electric field. In the conventional TFT liquid crystal display device using the TN method 50, the liquid crystal 52 is driven by the vertical electric field 51. Therefore, a transparent electrode such as an ITO vapor deposition film is used as the common electrode 55 on the color filter 54 which is the opposite substrate of the pixel electrode 53. Is formed. On the other hand, in the IPS system 56, the liquid crystal 52 is driven by the lateral electric field 57, so the common electrode 55 is formed on the same substrate 58 as the pixel electrode 53. The color filter 59 must be an insulator. That is, the IPS color filter 59 does not include a transparent electrode. The black matrix layer for shielding light is not a metal film for high electrical resistance, but a so-called resin black matrix in which a light shielding agent is dispersed in a resin. Furthermore, in the IPS method, since protection of pixels and particularly strict surface smoothness of the color filter and barrier properties for preventing impurities contained in the color filter layer from eluting into the liquid crystal are required, An overcoat layer 60 is provided on the colored layer. The overcoat layer is required to have a wide range of properties such as transparency, surface smoothness, adhesion to upper and lower adjacent layers, light resistance, heat resistance, chemical resistance, etc. Resistance light or thermosetting acrylic resins, urethane resins, polyglycidyl methacrylate resins, epoxy resins, and the like are used.

  However, since both the black matrix layer and the conventional overcoat layer have high electrical resistance, charges are generated and accumulated on the color filter during driving, and the screen is burned due to the influence of residual charges generated by long-term screen display. There was a problem of lighting (afterimage occurred).

Patent Document 1 proposes a method of using an inorganic material such as SiO ₂ that does not induce polarization in the protective film itself for the purpose of preventing afterimages. However, the inorganic protective film has problems of low adhesion to the black matrix layer and the colored layer and inferior surface smoothness of the color filter.

  Patent Document 2 discloses a liquid crystal display device in which a burn-in afterimage of a display image due to an internal residual voltage hardly occurs. However, there is no disclosure or suggestion about the afterimage of the IPS color filter.

JP-A-10-319382 JP 2000-19565 A

  An object of the present invention is to provide a color filter for obtaining a highly reliable liquid crystal display device which is excellent in surface smoothness, can reduce residual charge, and does not burn the screen even if the screen is displayed for a long time.

  The color filter provided in the present invention is a color filter that includes a transparent substrate and a colored layer provided on the transparent substrate and does not include an electrode, and the colored layer is covered with a conductive overcoat layer. It is characterized by.

From the viewpoint of preventing screen burn-in and crosstalk of the IPS liquid crystal display device, the conductive overcoat layer preferably has a volume resistivity of 1.0 × 10 ^{8 to} 1.0 × 10 ¹¹ Ω · cm.

  Moreover, it is preferable that the said conductive overcoat layer contains electroconductive particle from the point of the ease of control of electroconductivity, and heat resistance.

  In the color filter of the present invention, since the overcoat layer has conductivity, residual charges generated and accumulated on the color filter during driving can be effectively removed without staying. Therefore, it can be used as a color filter for obtaining a highly reliable liquid crystal display device in which the screen does not burn even when the screen is displayed for a long time.

  The color filter provided in the present invention is a color filter that includes a transparent substrate and a colored layer provided on the transparent substrate and does not include an electrode, and the colored layer is covered with a conductive overcoat layer. It is a color filter characterized by.

  In the color filter of the present invention, since the overcoat layer has conductivity, residual charges generated and accumulated on the color filter during driving can be effectively removed without staying. Therefore, it can be used as a color filter for obtaining a highly reliable liquid crystal display device in which the screen does not burn even when the screen is displayed for a long time.

Hereinafter, embodiments of the color filter of the present invention will be described.
FIG. 2 is a configuration example of an IPS liquid crystal panel. The liquid crystal panel 101 is provided with a gap portion 3 of about 1 to 10 μm so that the color filter 1 which is a display side substrate and the TFT substrate 2 face each other, the liquid crystal L is filled in the gap portion 3, and the periphery thereof is a sealing material 4 is sealed. The color filter 1 includes a black matrix layer 6 formed in a predetermined pattern on the transparent substrate 5 to shield the boundary between pixels, and a plurality of colors (usually red (R), green (G), A pixel 7 in which blue (B) (primary three colors)) are arranged in a predetermined order or a pixel using a hologram recently and an overcoat layer 8 are stacked in this order from the side close to the transparent substrate. The color filter 1 may be provided with a retardation layer (optical compensation layer) (not shown) between the transparent substrate 5 and the overcoat layer 8 in order to improve display characteristics. Specifically, for example, the retardation layer can be provided between the transparent substrate 5 and the black matrix layer 6 and the pixel 7 or between the black matrix layer 6 and the pixel 7 and the overcoat layer 8.

  On the other hand, the TFT substrate 2 has a structure in which a common electrode 9 and a pixel electrode 10 are provided on a transparent substrate. An alignment film 11 is provided on the inner surface side of the color filter 1 and the TFT substrate 2 facing the color filter 1. Further, in the gap portion 3, in order to maintain a constant and uniform cell gap between the color filter 1 and the TFT substrate 2, spherical or rod-shaped particles (not shown) made of glass, alumina, plastic or the like as spacers. ) Is distributed. Here, the spacer is not limited to the above-described particles, and may be a spacer composed of columnar convex portions formed on any substrate side, for example. In addition, deflecting plates (not shown) are disposed outside the color filter 1 and the TFT substrate 2, respectively.

  In the IPS system, an electric field is formed substantially parallel to the interface of the color filter 1 or the TFT substrate 2 by applying a voltage between the common electrode 9 formed on the TFT substrate 2 and the pixel electrode, and the gap in the gap 3 The liquid crystal molecules are deflected and rotated in a plane parallel to the color filter 1 and the TFT substrate 2, and the deflection axis of light from the light source is rotated, so that the pixel is turned on. In this way, a color image can be obtained by controlling the light transmittance of each pixel colored in each color or the liquid crystal layer behind the color filter.

  FIG. 3 is a plan view showing an example of the color filter (color filter 102) according to the present invention that can be used as the color filter 1 of FIG. 2, and FIG. FIG.

  The color filter 102 covers a black matrix 6 formed in a predetermined pattern on the transparent substrate 5, pixels 7 (7R, 7G, 7B) formed in a predetermined pattern on the black matrix, and covers the pixels. The formed overcoat layer 8 is provided. An alignment film 11 is formed on the innermost surface of the color filter 102, in this case on the overcoat layer.

  The columnar spacer 12 is a shape of a convex spacer, and is formed at a plurality of predetermined locations (five locations in FIG. 3) on the overcoat layer 8 in accordance with the region (non-display region) where the black matrix layer 6 is formed. Has been. The columnar spacer 12 is formed on the overcoat layer 8. When the color filter does not include a black matrix layer, columnar spacers can be formed in regions where pixels are not formed.

  The transparent substrate 5 of the color filter 102 is a transparent rigid material such as quartz glass, Pyrex (registered trademark) glass or synthetic quartz plate, or a flexible resin such as a transparent resin film or an optical resin plate. The transparent flexible material which has can be used. Among these, Corning 1737 glass is a material having a small coefficient of thermal expansion, excellent in dimensional stability and workability in high-temperature heat treatment, and is an alkali-free glass containing no alkali component in the glass. Suitable for color filters for matrix liquid crystal display devices.

  The black matrix layer 6 is provided so as to surround the pixels 7R, 7G, and 7B and the outside of the pixel formation region in order to improve the contrast of the display image. In the case of the IPS system, the black matrix layer 6 cannot be made of metal chromium or the like due to the problem of the resistance value, and is formed using a high resistance resin composition.

  For example, first, a curable resin composition containing light-shielding particles such as titanium oxide as a colorant is applied onto the transparent substrate 5 and dried as necessary to form a photosensitive coating film. The black matrix layer 6 can be formed by exposing and developing through a photomask for black matrix and subjecting to heat treatment as necessary. The thickness of the black matrix layer is about 0.5 to 2.5 μm.

  The pixel 7 is formed by arranging a red pattern, a green pattern, and a blue pattern in a desired form such as a mosaic type, a stripe type, a triangle type, or a four-pixel arrangement type, thereby forming a display region. The pixel can be formed by a known method such as a pigment dispersion method, a dyeing method, a printing method, or an electrodeposition method. Among them, a pigment dispersion method using a curable resin composition containing a colorant such as a pigment. It is preferable to form by.

  In the case of the pigment dispersion method, first, colorants such as pigments are dispersed in the curable resin composition to prepare photocurable colored resin compositions for red, green, and blue, respectively. Next, on the transparent substrate 5, a certain color, for example, a photocurable red resin composition is applied by a known method such as spin coating so as to cover the black matrix layer 6 to form a photocurable red resin layer. Then, exposure is performed through a photomask for red pattern, and after alkali development, the red pixel 7R is formed by heat curing in a clean oven or the like. Thereafter, green and blue photocurable colored resin compositions are sequentially used to pattern each color in the same manner to form green pixels 7G and blue pixels 7B. As the colorant, a known colorant can be appropriately selected and used.

  The thickness of the pixel is usually about 0.5 to 2.5 μm. Alternatively, the thickness of each color pixel may be changed so that the red pixel 7R is the thinnest, and the green pixel 7G and the blue pixel 7B become thicker in this order, and the optimal liquid crystal layer thickness may be set for each color.

  In the IPS system, the surface smoothness of the color filter is particularly required, and the overcoat layer 8 flattens the surface of the color filter and prevents the components contained in the pixels 7 from eluting into the liquid crystal layer. , Provided on the pixel. The term “on the pixel” may be directly formed on the pixel as shown in FIG. 4, but may be provided on another layer formed in advance on the pixel. The overcoat layer 8 is required to have transparency that does not affect the color display by the pixels.

The volume resistance value of the overcoat layer 8 is preferably 1.0 × 10 ^{8 to} 1.0 × 10 ¹¹ Ω · cm, more preferably 1.0 × 10 ^{9 to} 1.0 × 10 ¹⁰ Ω · cm. is there. When the volume resistance value of the overcoat layer exceeds 1.0 × 10 ¹¹ Ω · cm, it becomes difficult to remove the charges generated and accumulated in the liquid crystal alignment film in the liquid crystal display device. On the other hand, when the volume resistance value of the protective film is smaller than 1.0 × 10 ⁸ Ω · cm, the electrical insulation becomes insufficient, for example, conduction between the color filter and the counter substrate, and an electric field is generated in the vertical direction. Display defects are likely to occur due to disorder of the alignment of the liquid crystal. By setting the volume resistance value of the overcoat layer in the above range, it has an insulation property that does not conduct between the color filter substrate and the TFT substrate, and is generated and accumulated between the layers during manufacturing and driving. Can be effectively removed without stagnation. As a result, the conductive overcoat layer improves the display afterimage of the liquid crystal display device.

  The overcoat layer 8 includes at least a binder component and a conductive material, and is formed from an overcoat material having a transparency that does not affect the pixels.

  The overcoat material preferably has a light transmittance of 90% or more at a thickness of 1 μm and a thickness of 400 nm, and a color difference (C light source, ΔEab) before and after a heat test at 250 ° C. for 1 hour is 2 or less.

  As the binder component, a known negative photocurable transparent resin composition and / or thermosetting transparent resin composition can be used. Specifically, as the negative photocurable transparent resin composition, Monomer having at least one unsaturated bond group, and performing ion polymerization or radical polymerization by ions or radicals generated by irradiating the photopolymerization initiator with curing energy rays to increase molecular weight or form a crosslinked structure Or a combination of a simple substance or a mixture of oligomer and a polymer and a photopolymerization initiator.

  Examples of such monomers and oligomers include acrylic types such as epoxy acrylate, urethane acrylate, polyester acrylate, polyether acrylate, and silicon acrylate, and non-acrylic types such as unsaturated polyester / styrene and polyene / styrene. Of these, acrylic monomers and oligomers are preferred because of their wide range of curing speed and physical property selection. Typical examples of such acrylic monomers and oligomers are shown below. In addition, (meth) acryl means that it is either an acryl group or a methacryl group, and (meth) acrylate means that it is either an acrylate group or a methacrylate group.

  First, as a monofunctional group, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid, 2-ethylhexyl (meth) acrylate, 2-ethylhexyl ethylene oxide (hereinafter referred to as EO) adduct (meth) Acrylate, ethoxydiethylene glycol (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, caprolactone adduct of 2-hydroxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, phenoxy Diethylene glycol (meth) acrylate, nonylphenol EO adduct (meth) acrylate, (meth) acrylate added with caprolactone to nonylphenol EO adduct, 2-hydroxy-3-phenoxypropyl (meth) acrylate, tetrahydride Rofurfuryl (meth) acrylate, furfuryl (meth) alcohol caprolactone adduct (meth) acrylate, acryloylmorpholine, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, Isobornyl (meth) acrylate, (meth) acrylate of caprolactone adduct of 4,4-dimethyl-1,3-dioxolane, (meth) of caprolactone adduct of 3-methyl-5,5-dimethyl-1,3-dioxolane An acrylate etc. can be mentioned.

  In addition, as the polyfunctional group, hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, hydroxypivalate neopentyl glycol Ester di (meth) acrylate, caprolactone adduct of hydroxypivalic acid neopentyl glycol ester di (meth) acrylate, (meth) acrylic acid adduct of 1,6-hexanediol diglycidyl ether, hydroxypivalaldehyde and trimethylol Di (meth) acrylate of propane acetal compound, 2,2-bis [4-((meth) acryloyloxydiethoxy) phenyl] propane, 2,2-bis [4-((meth) acryloyloxydiethoxy) ) Phenyl] methane Di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane propylene oxide addition of hydrogenated bisphenol ethylene oxide adduct Tri (meth) acrylate, glycerin propylene oxide adduct tri (meth) acrylate, dipentaerythritol hexaacrylate penta (meth) acrylate mixture, dipentaerythritol caprolactone adduct (meth) acrylate, tris ((meth) acryloyloxy And ethyl) isocyanurate, 2- (meth) acryloyloxyethyl maleate and the like.

  As the polymer, a polymer or copolymer of the above-mentioned monofunctional monomer can be used. Further, a carboxyl group is introduced into the side chain, and an alkali developability is imparted to the polymer or side chain. It is also possible to use a polymer of a type to which radical reactivity has been imparted by introducing a group.

  As the photopolymerization initiator, a radical polymerizable initiator can be used. Radical polymerizable initiators are compounds that generate free radicals by the energy of ultraviolet rays, for example, and are derivatives such as benzophenone derivatives such as benzoin and benzophenone or their esters; xanthones and thioxanthone derivatives; chlorosulfonyl, chloromethyl polynuclear aromatics Halogen-containing compounds such as compounds, chloromethyl heterocyclic compounds and chloromethylbenzophenones; triazines; fluorenones; haloalkanes; redox couples of photoreductive dyes and reducing agents; organic sulfur compounds; is there. Preferably, Irgacure 184, Irgacure 369, Irgacure 651, Irgacure 907 (all manufactured by Ciba Specialty Chemicals), Darocur (Merck), Adeka 1717 (Asahi Denka Kogyo Co., Ltd.), 2 , 2′-bis (o-chlorophenyl) -4,5,4′-tetraphenyl-1,2′-biimidazole (manufactured by Kurokin Kasei Co., Ltd.) it can.

  Moreover, as a thermosetting transparent resin composition, the low molecular compound simple substance which has a reactive group hardened | cured by the addition reaction or condensation reaction by a thermal energy, or a mixture with a polymer is used. Representative examples include celoxide 2021, 2021A, 2021F, 2081, 2000, 3000 (manufactured by Daicel Chemical Industries) as an alicyclic epoxy resin, Eporide GT301, 401 (manufactured by Daicel Chemical Industries), and Epicoat 1001 as a bisphenol A type epoxy resin. 1002, 1003, 1004, 1007, 1009, 1010 (Japan Epoxy Resin), etc., Bisphenol F type epoxy resin, Epicoat 807 (Japan Epoxy Resin), etc., phenol novolac type epoxy resin, EPPN 201, 202 (Nippon Kayaku) EOCN102, 103S, 104S, 1020, 1025, 1027 (Japan) as cresol novolak type epoxy resins such as Epicoat 154 (manufactured by Japan Epoxy Resin) Of manufactured drug), it can be exemplified such as Epikote 180S (manufactured by Japan Epoxy Resins). Furthermore, aliphatic polyglycidyl ether can also be illustrated.

Examples of the conductive material include a conductive filler and a conductive polymer. Among the conductive fillers, conductive fine particles are preferable, and the conductive fine particles are not limited as long as they are conductive fine particles. Specifically, zinc oxide, tin oxide, indium oxide, antimony oxide, carbon nanotubes, And tin oxide doped with Sb, F, P and the like, and indium oxide doped with Sn, F and the like. Further, the conductive fine particles may be composite oxide fine particles such as TiO ₂ —SnO ₂ . These may be used alone or in combination. The particle diameter of the conductive fine particles is preferably 0.01 to 0.1 μm from the viewpoint of the transparency of the coating film and the dispersion stability of the overcoat material. On the other hand, the conductive polymer is not limited as long as it is a polymer compound exhibiting conductivity, and specific examples include polythiophene, polyacetylene, polypyrrole, and polyphenylene vinylene.

  As the conductive material, conductive fine particles are preferable from the viewpoint of easy adjustment of conductivity, and among them, indium oxide doped with Sn, so-called ITO is particularly preferable from the viewpoint of transparency.

  The conductive material is preferably contained in the overcoat material in an amount of 30 to 60% by mass with respect to the total solid content. In addition, solid content means all the components except a solvent, and liquid components other than a solvent are also contained.

  When conductive fine particles are used as the conductive material, a dispersant may be blended in order to improve the dispersibility of the conductive fine particles.

  As the dispersant, the following polymer dispersants, that is, (meth) acrylic acid-based (co) polymer polyflow No. 75, No. 90, No. 95 (manufactured by Kyoeisha Yushi Chemical Co., Ltd.), Megafac F171 , F172, F173 (Dainippon Ink and Chemicals), Florard Fc430, Fc431 (Sumitomo 3M), Solsperse 13240, 20000, 24000, 26000, 28000, etc. 162, 163, 164, 182, 2000, 2001 (manufactured by Big Chemie), Addisper PB711, PB411, PB111, PB821, PB822 (manufactured by Ajinomoto Fine Techno) and the like can be used.

  The overcoat layer 8 is coated with a coating solution of an overcoat material so as to cover the black matrix layer 6 and the pixels 7 by a method such as spin coater, roll coater, spray, printing, etc. Then, it can form by making it harden | cure by light, such as an ultraviolet-ray, and / or about 150-250 degreeC.

  The thickness of the overcoat layer is set in consideration of the light transmittance of the composition, the surface state of the color filter, and the like, and is, for example, about 0.1 to 2.0 μm. When using a spin coater, the number of revolutions is usually set within a range of 500 to 1500 revolutions / minute.

  A plurality of convex spacers are provided in a non-display area on the substrate in order to maintain a cell gap when the color filter 102 is bonded to a counter substrate (liquid crystal driving side substrate) such as a TFT array substrate. The shape and size of the convex spacer are not particularly limited as long as it can be selectively provided in a non-display region on the substrate and can maintain a predetermined cell gap over the entire substrate. When the columnar spacer 12 as shown in the figure is formed as the convex spacer, it has a certain height in the range of about 2 to 10 μm, and the protruding height (pattern thickness) is required for the liquid crystal layer. It can set suitably from thickness etc. Moreover, the thickness of the columnar spacer 12 can be appropriately set within a range of about 5 to 20 μm. In addition, the number of column spacers 12 (concentration) can be appropriately set in consideration of the thickness unevenness of the liquid crystal layer, the aperture ratio, the shape of the column spacers, the material, etc. For example, each of red, green and blue Necessary and sufficient spacer functions are expressed at a ratio of one pixel to one set of pixels. The shape of such a columnar spacer may be a columnar shape, and may be, for example, a columnar shape, a prismatic shape, a truncated cone shape, or the like.

  In order to form the convex spacer, first, the coating liquid of the curable resin composition is directly applied on the transparent substrate by a method such as spin coater, roll coater, spray, printing, or another layer such as an overcoat. And is dried to form a photocurable resin layer. The rotational speed of the spin coater may be set within the range of 500 to 1500 revolutions / minute, as in the case of forming the overcoat layer. Next, this resin layer is exposed through a photomask for convex spacers, and developed with a developer such as an alkaline solution to form a predetermined convex pattern. A convex spacer is formed by heat treatment (post-bake) or the like.

  The alignment film 11 is provided on the inner surface side of the color filter so as to cover the display unit including the pixels 7 and the non-display unit including the black matrix layer 6 and the columnar spacers 12. The alignment film can be formed by applying a coating solution containing a resin such as a polyimide resin by a known method such as spin coating, drying, curing with heat or light as necessary, and then rubbing.

  The color filter according to the present invention thus obtained is a color filter that can reduce a residual charge and can provide a highly reliable liquid crystal display device in which the screen does not burn even when the screen is displayed for a long time.

  When the obtained color filter 102 (display side substrate) and the opposite substrate substrate (liquid crystal driving side substrate) such as a TFT array are opposed to each other and the inner peripheral side edge portions of both substrates are bonded with a sealant, the both substrates have a predetermined distance. Bonding is performed with the cell gap maintained. An active matrix color liquid crystal display device, which is an example of a liquid crystal display device, can be obtained by filling the liquid crystal in the gap between the substrates and sealing the liquid crystal. The liquid crystal display device thus obtained is excellent in display quality because the screen does not burn even when the screen is displayed for a long time.

(Example 1: Production of color filter)
(1) Preparation of Overcoat Material Synthesis of Polymer 1 15.6 parts by weight of benzyl methacrylate, 37.0 parts by weight of styrene, 30.5 parts by weight of acrylic acid, and 2-hydroxyethyl methacrylate in a polymerization tank 16.9 parts by weight, 200 parts by weight of diethylene glycol dimethyl ether (DMDG) were charged, stirred and dissolved, then 0.8 part by weight of 2,2′-azobis (isobutyronitrile) was added and dissolved uniformly. I let you. Then, it stirred at 85 degreeC under nitrogen stream for 2 hours, and also was made to react at 100 degreeC for 1 hour. Further, 16.9 parts by weight of 2-methacryloyloxyethyl isocyanate, 0.5 part by weight of triethylamine and 0.1 part by weight of hydroquinone were added to the obtained solution, and the mixture was stirred at 100 ° C. for 5 hours. Polymer 1 (solid content 37.2%) was obtained.

  An overcoat material was prepared by mixing and stirring with the composition shown in Table 1.

(2) Formation of black matrix The resin composition for black matrix shown in Table 2 was applied to a 1.1 mm thick glass substrate (AL material manufactured by Asahi Glass Co., Ltd.) with a spin coater, and dried at 100 ° C for 3 minutes. A light shielding layer having a thickness of about 1 μm was formed. The light-shielding layer is exposed to a light-shielding pattern with an ultra-high pressure mercury lamp, developed with a 0.05% aqueous potassium hydroxide solution, and then subjected to heat treatment by leaving the substrate in an atmosphere at 180 ° C. for 30 minutes. A black matrix was formed in a region where a light shielding portion should be formed.

(3) Formation of colored layer On the substrate on which the black matrix was formed as described above, the red pattern resin composition shown in Table 3 was applied by spin coating (application thickness: 1.5 μm), and then 70 ° C. In the oven for 30 minutes.

  Next, a photomask is placed at a distance of 100 μm from the coating film of the resin composition for red pattern, and ultraviolet rays are applied only to the region corresponding to the colored layer formation region using a 2.0 kW ultrahigh pressure mercury lamp by a proximity aligner. Irradiated for 10 seconds. Subsequently, it was immersed in 0.05 wt% potassium hydroxide aqueous solution (liquid temperature 23 degreeC) for 1 minute, and alkali development was carried out, and only the uncured part of the coating film of the resin composition for red patterns was removed. Thereafter, the substrate was left in an atmosphere of 180 ° C. for 30 minutes to perform heat treatment, thereby forming a red relief pattern in a region where a red pixel was to be formed.

  Next, using the green pattern resin composition shown in Table 4, a green relief pattern was formed in a region where a green pixel was to be formed, in the same process as the red relief pattern formation.

  Further, using the blue curable resin composition of Table 5, a blue relief pattern is formed in a region where a blue pixel is to be formed in the same process as the formation of the red relief pattern, and red (R), green ( A colored layer composed of three colors of G) and blue (B) was formed.

(4) Formation of overcoat layer The overcoat material synthesized in (1) was applied by a spin coating method on a glass substrate on which a colored layer was formed, and dried to form a coating film having a dry film thickness of 1.0 μm.

  A photomask was placed at a distance of 100 μm from the coating film of the overcoat material, and ultraviolet rays were irradiated for 10 seconds only to the region corresponding to the colored layer formation region using a 2.0 kW ultrahigh pressure mercury lamp by a proximity aligner. Subsequently, it was immersed in 0.05 wt% potassium hydroxide aqueous solution (liquid temperature 23 degreeC) for 1 minute, and alkali image development was carried out, and only the uncured part of the coating film of an overcoat material was removed. Thereafter, the substrate was left to stand in an atmosphere at 200 ° C. for 30 minutes to perform a heat treatment to form an overcoat layer.

(5) Formation of Spacer On the glass substrate on which the colored layer was formed, the columnar spacer resin composition shown in Table 6 was applied and dried by a spin coating method to form a coating film having a dry film thickness of 5 μm.

  Place a photomask at a distance of 100 μm from the coating film of the resin composition for columnar spacers and use a 2.0 kW ultrahigh pressure mercury lamp with a proximity aligner to apply ultraviolet light only to the spacer formation area on the black matrix for 10 seconds. Irradiated. Subsequently, it was immersed in 0.05 wt% potassium hydroxide aqueous solution (liquid temperature 23 degreeC) for 1 minute, and alkali image development was carried out, and only the uncured part of the coating film of the resin composition for columnar spacers was removed. Thereafter, the substrate was left to stand in an atmosphere of 200 ° C. for 30 minutes to perform a heat treatment to form a fixed spacer. Further, an alignment film made of a material containing at least one of polyimide, polyamide, polyurethane, and polyurea organic compounds was formed on the surface including the fixed spacer to obtain the color filter of the present invention.

(Example 2, comparative example 1: color filter)
A color filter was produced in the same manner except that the overcoat material having the composition shown in Table 1 was used as the overcoat material.
<Evaluation>
(1) Production of liquid crystal panel The color filter obtained in Example 1 and the glass substrate on which the TFT was formed were bonded using epoxy resin as a sealing material at 150 ° C. and a pressure of 0.3 kg / cm ^2. Then, the cells were assembled, and liquid crystal (ZLI4792, manufactured by Merck & Co., Inc.) was sealed to produce a liquid crystal display device.

(2) Evaluation of transmittance The transmittance of light (wavelength: 400 nm) of a conductive overcoat produced on a glass substrate to a thickness of 1 μm is used as a reference by using a glass substrate as a reference (UV-3100PC: manufactured by Shimadzu Corporation) ).

(3) Evaluation of heat resistance (color difference) Spectral transmission curves before and after a heat test at 250 ° C. for 1 hour of a conductive overcoat made on a glass substrate with a thickness of 1 μm were measured with a microspectrophotometer (Olympus OSP-SP100). The maximum and minimum changes in transmittance were measured, and the color difference (C light source, ΔEab) before and after the heat resistance test was determined.

(4) Evaluation of volume resistivity The volume resistivity of a 3 μm-thick conductive overcoat produced on a 1 mm, 10 cm × 10 cm chrome substrate is a high resistivity meter manufactured by Mitsubishi Chemical Corporation in accordance with JISK6911. Measurement was performed using a Hiresta UP (MCP-HT450) in an environment with a relative humidity of 65% at 23 ° C.

(5) Evaluation of residual charge Using RDC-1 (manufactured by Toyo Technica Co., Ltd.), by applying a capacitor dielectric absorption method, DC10V was applied at 25 ° C. for 30 minutes and then shorted for 1 second, and the voltage value after 10 minutes was measured ( Measurement temperature; 25 ° C.).

(6) Evaluation of Burning Afterimage After applying a fixed pattern on the display area for 48 hours at 60 ° C., the pattern application was stopped and the display afterimage (baking afterimage) was observed and evaluated. However, the evaluation criteria are as follows.
○: A slight afterimage level at which the burn-in afterimage disappears within 1 second. X: An afterimage level at which the burn-in afterimage does not disappear even after 30 seconds.

<Evaluation results>
Table 7 shows the evaluation results of the liquid crystal display devices using the color filters of Examples 1 and 2 and Comparative Example 1 using the overcoat materials of Production Examples 1 and 2 and Comparative Production Example 1. In the liquid crystal display device using the color filter according to the present invention, the residual charge was greatly reduced, and the screen did not burn even when the screen was displayed for a long time.

It is a figure which shows notionally the difference in the liquid crystal drive of a TN system and an IPS system. It is a typical sectional view about an example of 1 composition of a liquid crystal panel of an IPS system. It is a top view which shows an example of the color filter which concerns on this invention. It is a longitudinal cross-sectional view in the AA line of the color filter which concerns on this invention of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Color filter 101 ... Liquid crystal panel 102 ... Color filter 2 ... Electrode board 3 ... Gap part 4 ... Sealing material 5 ... Transparent substrate 6 ... Black matrix layer 7 (7R, 7G, 7B) ... Pixel 8 ... Overcoat layer 9 ... Common electrode 10 ... Pixel electrode 11 ... Alignment film 12 ... Columnar spacer 50 ... TN system 51 ... Vertical electric field 52 ... Liquid crystal 53 ... Pixel electrode 54 ... Color filter 55 ... Common electrode 56 ... IPS system 57 ... Horizontal electric field 58 ... Substrate 59 ... Color filter 60 ... Overcoat layer

Claims (5)

  A color filter comprising a transparent substrate and a colored layer provided on the transparent substrate and not having an electrode, wherein the colored layer is coated with a conductive overcoat layer. The color filter according to claim 1, wherein the conductive overcoat layer has a volume resistivity of 1.0 × 10 ^{8 to} 1.0 × 10 ¹¹ Ω · cm.   The color filter according to claim 1, wherein the conductive overcoat layer contains conductive fine particles.   The color filter according to claim 3, wherein the conductive fine particles are ITO. The color filter according to any one of claims 1 to 4, which is an IPS color filter.

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