JP2007102243A - Color filter and method for producing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for industrially advantageously producing a color filter having such high reliability and high quality as not to cause deterioration in display quality due to faulty alignment of a liquid crystal, malfunction of TFT and inadequate voltage control. <P>SOLUTION: The color filter is obtained by forming light shielding pixels and pixels of three primary colors on a transparent substrate, wherein the pixels of three primary colors have a thickness difference in the pixels of ≤0.6 μm. In the method for producing the color filter obtained by forming light shielding pixels and pixels of three primary colors on a transparent substrate, the light shielding pixels are formed through (1) a step of forming a pigment-containing resin film by applying and drying a pigment-containing photosensitive resin composition on the transparent substrate, (2) a step of exposing the pigment-containing resin film through a mask and (3) a step of developing the pigment-containing resin film with a liquid which dissolves the unexposed portion of the pigment-containing resin film, and then the pixels of three primary colors are formed, wherein the photosensitive resin composition is applied so that the thickness of the pigment-containing resin film after drying is set to ≤1.5 μm, and the pixels of three primary colors are formed so that the thickness difference in the pixels is reduced to ≤0.6 μm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a color filter that can be suitably used for color display of liquid crystal display elements such as STN, MIM, and TFT, and a method for manufacturing the same.

  The color filter is a regular arrangement of light-shielding pixels called red, green, blue, and black matrices of the three primary colors on a transparent substrate such as glass or plastic by methods such as printing, electrodeposition, dyeing, and pigment dispersion. Formed. Regarding manufacturing methods, heat resistance, light resistance, flatness, pattern accuracy, productivity, production cost, display contrast, etc. are current and different, and the manufacturing method is properly used depending on the application. The law is excellent.

  Taking a pigment dispersion method, which is a typical production method of a color filter, as an example, a photosensitive resin composition usually called a color resist, in which a color pigment is blended on a transparent substrate on which a light-shielding pixel called a black matrix is usually formed. Is applied to the entire substrate, exposed and developed to form a colored image. In order to form the three primary colors red, green and blue, the steps from coating to development are repeated for the number of times of color.

  In order to form the black matrix, first, a metal thin film such as chromium is formed on the entire surface of the transparent substrate by a method such as vacuum deposition. Next, a photoresist is applied thereon, and the photoresist is exposed and developed with ultraviolet light through a mask to form the same resist pattern as the mask. By performing chromium etching using the resist pattern as a protective film, a chromium portion not covered with the resist can be etched. Thereafter, the photoresist is removed by plasma treatment or a resist stripping solution to form a chromium black matrix.

  Thus, the conventional color filter manufacturing method is expensive because of the long process. In particular, the process of forming the black matrix is long and the productivity is poor, which is a main cause of cost increase. In addition, since chromium is used for the black matrix, there is a problem in terms of environmental safety such as waste liquid treatment. Furthermore, since metallic chrome has a high reflectance, the color display quality of the liquid crystal is also adversely affected.

  As described above, there is a strong demand for a method to change to the chrome black matrix because there are problems in the quality and productivity of the color filter in the black matrix formation process, and the resin black matrix has the potential. Therefore, it has been studied energetically. The resin black matrix is patterned with a resist in which a light-shielding pigment is mixed with a photosensitive resin. Coating and patterning can be performed significantly more easily than a chrome black matrix, and there is no harmfulness. To compensate for the weaknesses of

  However, the conventional color filter may cause poor display quality due to poor alignment of the liquid crystal, TFT malfunction, insufficient voltage control, especially such a color filter using a resin black matrix, Not yet commercialized.

  That is, an object of the present invention is to provide a reliable and high-quality color filter that does not cause deterioration in display quality due to poor alignment of liquid crystals, defective TFT operation, or insufficient voltage control. Another object of the present invention is to produce such a high-quality color filter industrially advantageously by a method of forming a black matrix by a pigment dispersion method with sufficiently high productivity and low cost as compared with a conventional chromium black matrix. That is true.

  As a result of intensive studies to solve the problems of the conventional color filter, the present inventors paid attention to the fact that there is a film thickness difference in the three primary color pixels formed on the transparent substrate. It was found that by setting the thickness to 6 μm or less, a high-quality color filter in which the above-described problems were solved could be obtained, and the present color filter was reached. In addition, when forming a black matrix by the pigment dispersion method, the photosensitive resin composition is applied on a transparent substrate so that the thickness of the pigment-containing resin film for forming the black matrix after drying is 1.5 μm or less. It has been found that by forming the three primary color pixels so that the film thickness difference within the pixel is 0.6 μm or less, such a high-quality color filter can be produced industrially advantageously, and the present invention has been achieved. did.

  That is, the gist of the present invention is a color filter in which a light-shielding pixel and three primary color pixels are formed on a transparent substrate, and the film thickness difference in the three primary color pixels is 0.6 μm or less. In a color filter having a feature and a method for producing a color filter in which a light-shielding pixel and three primary color pixels are formed on a transparent substrate, the light-shielding pixel is 1) a photosensitive resin composition containing a pigment. A step of coating on and drying to form a pigment-containing resin film, 2) a step of exposing the pigment-containing resin film through a mask, and 3) a step of developing with a liquid that dissolves an unexposed portion of the pigment-containing resin film After forming the three primary color pixels, the photosensitive resin composition is applied so that the thickness of the pigment-containing resin film after drying is 1.5 μm or less. , In pixel The color filter manufacturing method is characterized in that the film thickness difference is 0.6 μm or less.

  The color filter of the present invention has high reliability and high quality such that there is no deterioration in display quality due to poor alignment of liquid crystals, defective TFT operation, and insufficient voltage control. According to the method of the present invention, such a high-quality, high-reliability color filter can be provided industrially advantageously.

  Hereinafter, the present invention will be described in detail. As the transparent substrate used in the color filter of the present invention, plastics such as polycarbonate and PMMA, glass, and the like can be used, but it is preferable to use glass from the viewpoint of the coefficient of thermal expansion and chemical resistance. The glass is preferably selected from alkali glass, non-alkali glass and the like according to the type of liquid crystal display element such as TFT, MIM, STN and the like.

  In order to form a resin black matrix on this transparent substrate, a composition containing a black pigment and a resin may be applied, and the composition is not particularly limited. However, black is a photosensitive resin composition containing a black pigment. It is advantageous to apply a resist. Various types of black resists such as polymerization type, light dimerization type, chemical amplification type, and light dissolution type can be used, but photopolymerization type from the viewpoint of sensitivity, pigment dispersibility, heat resistance, chemical resistance, etc. It is preferable to use a black resist.

The polymerizable black resist contains at least a polymerization initiator, a monomer that cures by the action of the polymerization initiator, and a black pigment, and may further contain a binder resin, a solvent, and the like as necessary. A preferable selection method for each component will be described below. The binder resin can be used if it has a coating film forming function, for example,
1) Polyolefin polymer polyethylene, polypropylene, polyisobutylene, etc. 2) Diene polymer polybutadiene, polyisoprene, etc. 3) Polymer polyacetylene polymer having conjugated polyene structure, polyphenylene polymer, etc. 4) Vinyl polymer Polyvinyl chloride, polystyrene, vinyl acetate , Polyvinyl alcohol, polyacrylic acid, polyacrylic acid ester, polyacrylamide, polyacrylonitrile, polyvinylphenol, etc. 5) Polyether polyphenylene ether, polyoxirane, polyoxetane, polytetrahydrofuran, polyether ketone, polyether ether ketone, polyacetal, etc. 6 ) Phenol resin novolak resin, resole resin, etc. 7) Polyester polyethylene terephthalate, polyphenol Phthalein terephthalate, polycarbonate, alkyd resin, unsaturated polyester resin, etc. 8) Polyamide nylon-6, nylon 66, water-soluble nylon, polyphenyleneamide, etc. 9) Polypeptide gelatin, casein, etc. 10) Epoxy resin and its modified novolak epoxy resin 11) Other polyurethane, polyimide, melamine resin, urea resin, polyimidazole, polyoxazole, polypyrrole, polyaniline, polysulfide, polysulfone, celluloses and the like.

  Among these resins, alkali-soluble resins are preferable from the viewpoint of pollution prevention, and examples of such resins include those having a carboxyl group or a phenolic hydroxyl group in the resin side chain or main chain. In particular, a resin having a carboxyl group, for example, an acrylic acid (co) polymer, a styrene / maleic anhydride resin, an acid anhydride-modified resin of novolak epoxy acrylate, and the like are preferable because of high alkali developability.

  Furthermore, an acrylic resin is preferable because it is excellent in developability, and a copolymer thereof is more preferable from the viewpoint of performance and production control because various monomers can be selected and polymerized. More specifically, the acrylic resin containing a carboxyl group is, for example, a monomer having a carboxyl group such as (meth) acrylic acid, (anhydrous) maleic acid, crotonic acid, itaconic acid, fumaric acid, styrene, α-methyl, etc. Styrene, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, vinyl acetate, acrylonitrile, (meth) acrylamide, glycidyl (meth) ) Acrylate, allyl glycidyl ether, glycidyl ethyl acrylate, glycidyl crotonic acid ether, (meth) acrylic acid chloride, benzyl (meth) acrylate, hydroxyethyl (meth) acrylate, N-methylol acrylamide, N, N dimethylacrylamid , N- methacryloyl morpholine, N, N- dimethylaminoethyl (meth) acrylate, N, N- dimethylaminoethyl acrylamide, polymers obtained by copolymerizing comonomers such. Among them, an acrylic resin containing at least (meth) acrylic acid or (meth) acrylic acid alkyl ether as a constituent monomer is preferable, and an acrylic resin containing (meth) acrylic acid and styrene is more preferable.

  Moreover, these resins can also add an ethylenic double bond to the resin side chain. Since the photocurability is increased by imparting a double bond to the resin side chain, the resolution and adhesion can be further improved, which is preferable. Examples of the synthesis means for introducing an ethylenic double bond include the methods described in JP-B-50-34443, JP-B-50-34444, and the like. Specific examples include a method of reacting a compound having both a glycidyl group, an epoxycyclohexyl group and a (meth) acryloyl group with a carboxyl group or a hydroxyl group, or acrylic acid chloride. For example, glycidyl (meth) acrylate, allyl glycidyl ether, glycidyl α-ethyl acrylate, crotonyl glycidyl ether, (iso) crotonic acid glycidyl ether, (3,4-epoxycyclohexyl) methyl (meth) acrylate, (meth) By using a compound such as acrylic acid chloride or (meth) allyl chloride and reacting with a resin having a carboxyl group or a hydroxyl group, a resin having a polymer group in the side chain can be obtained. In particular, a resin obtained by reacting (3,4-epoxycyclohexyl) methyl (meth) acrylate is preferable.

  In this specification, “(meth) acryl-”, “(meth) acrylate” and the like mean “acryl- or methacryl-”, “acrylate or methacrylate”, and the like, for example, “(meth) acryl” "Acid" shall mean "acrylic acid or methacrylic acid". When the preferable range of the weight average molecular weight measured by GPC of these acrylic resins exceeds 1000 to 100,000, the developability tends to decrease. Moreover, the range of preferable content of a carboxyl group is 5-200 in an acid value. When the acid value is 5 or less, it becomes insoluble in an alkaline developer, and when it exceeds 200, the sensitivity may be lowered.

  As the monomer that is cured by the action of the polymerization initiator, any known monomer can be used, but a monomer that undergoes radical polymerization by the action of a radical generated by the photopolymerization initiator is preferred. Typical examples include monomers having an ethylenic double bond, and more specifically, isobutyl acrylate, t-butyl acrylate, lauryl acrylate, cetyl acrylate, stearyl acrylate, cyclohexyl acrylate, isobornyl acrylate, benzyl acrylate. 2-methoxyethyl acrylate, 3-methoxybutyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, tetrahydrofuryl acrylate, phenoxy polyethylene glycol acrylate, methoxypropylene glycol acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2- Acryloyloxyethyl hydrogen phthalate, 2-acryloyloxypropyl Idrogen phthalate, 2-acryloyloxypropyl hydrogen phthalate, 2-acryloyloxypropyl tetrahydrohydrogen phthalate, morpholinoethyl methacrylate, trifluoroethyl acrylate, trifluoroethyl methacrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) Acrylate, octafluoropentyl (meth) acrylate, heptadecafluorododecyl acrylate, trimethylsiloxyethyl methacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl Glycol diacrylate, tetraethylene glycol diacrylate, tripropylene glycol Diacrylate, propylene glycol diacrylate, glycerin methacrylate acrylate, bisphenol A, ethylene oxide adduct diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, trimethylolpropane ethylene oxide addition triacrylate, glycerin propylene Oxide-added triacrylate, trisacryloyloxyethyl phosphate, dipentaerythritol hexaacrylate, modified novolak epoxy with acrylic acid, modified novolac epoxy with acrylic acid and anhydride, N-vinylpyrrolidone, N-vinylcaprolactam, acrylic Isocyanurate, dipentaerythritol mono Examples thereof include hydroxypentaacrylate, urethane acrylate, and unsaturated polyester acrylate.

  Among these monomers, an acrylic monomer, particularly an acrylic monomer having 3 or more double bonds, is preferable from the viewpoints of sensitivity, film strength, chemical resistance, and the like. These monomers are used alone or in combination. Examples of the polymerization initiator include those that generate an active compound that polymerizes an unsaturated compound by light irradiation. Specifically, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′- Tetraphenylbiimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (p-carboethoxy) phenylbiimidazole, 2,2′-bis (o-chlorophenyl)- 4,4 ′, 5,5′-tetra (p-bromophenyl) biimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (o, p-dichlorophenyl) Biimidazole, 2,2′-bis (o-bromophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o, p-dichlorophenyl) -4,4 ′, 5,5'-teto Phenylbiimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (m-methoxydiphenyl) biimidazole, 2,2′-bis (o-nitrophenyl) -4 , 4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-methylphenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, and other biimidazole derivatives, (4 -Methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2-((4-ethoxynaphthyl) ) -4,6-bis (trichloromethyl) -s-triazine, 2-ethoxycarbonyl-4- (4-ethoxynaphthyl) -4,6-bis (trichloromethyl) -s- Halomethylated triazine derivatives such as lyazine, halomethylated oxadiazole derivatives, benzoin such as benzoin methyl ether, benzoin phenyl ether, benzoin isobutyl ether, benzoin isopropyl ether, benzoin alkyl ethers, 2-methylanthraquinone, 2-ethylanthraquinone, Anthraquinone derivatives such as 2-t-butylanthraquinone, 1-chloroanthraquinone, benzanthrone derivatives, benzophenone, 4,4′-bis (dimethylamino) benzophenone (“Michler's ketone”), 4,4′-bis (diethylamino) benzophenone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone Benzophenone derivatives such as 2-carboxybenzophenone, 2,2, -dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, α-hydroxy-2-methylphenylpropanone, 1-hydroxy -1-methylethyl- (p-isopropylphenyl) ketone, 1-hydroxy-1- (p-dodecylphenyl) ketone, 2-methyl- (4 ′-(methylthio) phenyl) -2-morpholino-1-propanone, Acetophenone derivatives such as 1,1,1, -trichloromethyl- (p-butylphenyl) ketone, thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4- Diechi Thioxanthone derivatives such as thioxanthone 2,4-diisopropyl oxanthone, benzoic acid ester derivatives such as ethyl p-dimethylaminobenzoate and ethyl p-diethylaminobenzoate, 9-phenylacridine, 9- (p-methoxyphenyl) acridine and the like Acridine derivatives, phenazine derivatives such as 9,10-dimethylbenzphenazine, di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti- Bis-2,3,4,5,6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclo Pentadienyl-Ti-bis-2,4,6-trifluorophen-1-yl Di-cyclopentadienyl-Ti-2,6-di-fluorophen-1-yl, di-cyclopentadienyl-Ti-2,4-di-fluorophen-1-yl, di-methylcyclopenta Dienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, And titanocene derivatives such as di-cyclopentadienyl-Ti-2,6-di-fluoro-3- (pyr-1-yl) -phen-1-yl.

  Among these polymerization initiators, biimidazole derivatives, triazine derivatives, oxadiazole derivatives, and titanocene derivatives are preferable because of their high sensitivity and high resolution. These polymerization initiators can be used alone or in combination. In particular, in the case of a biimidazole derivative or a titanocene derivative, it is preferable to use a plurality of polymerization initiators together. Preferred examples of the combination are, for example, JP-B 53-12802, JP-A-1-279903, JP-A-2-48664, and JP-A-2-48664. 4-164902, JP-A-6-75373, and the like.

As a black pigment, there is a method of mixing a plurality of organic pigments, for example, red, green, blue, etc. to make it black, but it is necessary to add a large amount of pigment in order to achieve high light shielding properties. On the other hand, carbon black is preferable to a mixed color of organic pigments because it has sufficient light shielding properties when used alone. Examples of the carbon black include carbon black # 2400, # 2350, # 2300, # 2200, # 1000, # 980, # 970, # 960, # 950, # 900, # 850, MCF88 manufactured by Mitsubishi Chemical Corporation. # 650, MA600, MA7, MA8, MA11, MA100, MA220, IL30B, IL31B, IL7B, IL11B, IL52B, # 4000, # 4010, # 55, # 52, # 50, # 47, # 45, # 44, # 40, # 33, # 32, # 30, # 20, # 10, # 5, CF9, # 3050, # 3150, # 3250, # 3750, # 3950, Diamond Black A, Diamond Black N220M, Diamond Black N234, Diamond Black I, Diamond Black LI, Diamond Black II, Diamond Black N 39, Diablack SH, Diablack SHA, Diablack LH, Diablack H, Diablack HA, Diablack SF, Diablack N550M, Diablack E, Diablack G, Diablack R, Diablack N760M, Diablack LR. Carbon black thermax N990, N991, N907, N908, N990, N991, N908 made by Cancarb. Carbon black Asahi # 80, Asahi # 70, Asahi # 70L, Asahi F-200, Asahi # 66, Asahi # 66HN, Asahi # 60H, Asahi # 60U, Asahi # 60, Asahi # 55, Asahi # 50H, Asahi # 51, Asahi # 50U, Asahi # 50, Asahi # 35, Asahi # 15, Asahi Thermal, Degussa Carbon Black ColorBlack
Fw200, ColorBlackFw2, ColorBlack Fw2V, ColorBlack Fw1, ColorBlack Fw18, ColorBlack S170, ColorBlack
S160, Special Black 6, Special Black 5, Special Black 4, Special Black 4A, Printex U, Printex V, Printex 140U, Printex 140V, and the like. Among these carbon blacks, those having a specific surface area of 100 m <2> / g or less and a physical property value of PH of 2 to 9 are particularly preferable because of good dispersion stability and high light shielding properties.

From the viewpoint of dispersibility, it is advantageous to contain a dispersant in the composition. Examples of the dispersant include a polymer dispersant, and more specifically, a polyester or polyether having a basic functional group. The basic functional group is preferably an amine in the range of 1 to 100 mgKOH / g from the viewpoints of dispersion stability, developability and resolution. The functional group is preferably present at the resin terminal. The molecular weight is preferably in the range of 1000 to 100,000 in terms of polystyrene equivalent weight average in terms of dispersion stability, developability and resolution. Specific examples of the polymer dispersant satisfying such conditions include Disperbyk160, Disperbyk161, Disperbyk162, Disperbyk163, Disperbyk164, Disperbyk166 manufactured by BYK Chemie;
Commercial products such as SOLSPERSE 20000, SOL SPERSE 24000, SOL SPERSE 27000, SOL SPERSE 28000, etc. (all are trade names) manufactured by Zeneca. The dispersant is about 2 to 50% by weight based on the pigment. In using the dispersant, there is a method of dispersing the pigment in advance and blending it into the composition. Further, the composition may contain an additive such as a surfactant for the purpose of improving coatability.

In the method of the present invention, diisopropyl ether, mineral spirit, n-pentane, amyl ether, ethyl caprylate, n-hexane, diethyl ether, isoprene, ethyl isobutyl ether, butyl stearate are used as solvents for improving dispersibility and coating properties. , N-octane, Barsol # 2, Apco # 18 solvent, diisobutylene, amyl acetate, butyl butyrate, apcocinner, butyl ether, diisobutyl ketone, methylcyclohexene, methyl nonyl ketone, propyl ether, dodecane, Socal
solvent NO1 and No2, amyl formate, dihexyl ether, diisopropyl ketone, Solvesso # 150, (n, sec, t) -butyl acetate, hexene, shell TS28 solvent, butyl chloride, ethyl amyl ketone, ethyl benzoate, amyl chloride, Ethylene glycol diethyl ether, ethyl orthoformate, methoxymethylpentanone, methyl butyl ketone, methyl hexyl ketone, methyl isobutyrate, benzonitrile, ethyl propionate, methyl cellosolve acetate, methyl isoamyl ketone, methyl isobutyl ketone, propyl Acetate, amyl acetate, amyl formate, bicyclohexyl, diethylene glycol monoethyl ether acetate, dipentene, methoxy Methylpentanol, methyl amyl ketone, methyl isopropyl ketone, propyl propionate, propylene glycol-t-butyl ether, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, ethyl cellosolve acetate, carbitol, cyclohexanone, ethyl acetate, propylene glycol, propylene glycol monomethyl Ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, dipropylene glycol monoethyl ether, dipropylene glycol monomethyl ether, propylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, 3 -Methoxypro Pionic acid, 3-ethoxypropionic acid, methyl ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate , Diglyme, dipropylene glycol monomethyl ether, ethylene glycol acetate, ethyl carbitol, butyl carbitol, ethylene glycol monobutyl ether, propylene glycol-t-butyl ether, 3-methyl-3-methoxybutanol, tripropylene glycol methyl ether, 3- An organic solvent such as methyl-3-methoxybutyl acetate can be used. Two or more of these solvents can be used in combination. Further, it is preferable to select a solvent having a boiling point in the range of 100 ° C to 200 ° C. More preferably, it has a boiling point of 120 ° C to 170 ° C.

  The preferred blending ratio of the above binder resin, unsaturated compound, polymerization initiator and black pigment is 10 to 50 wt% for the binder resin, 5 to 35 wt% for the unsaturated compound, 0.1 to 10 wt% for the polymerization initiator, and black pigment. Is in the range of 35 to 70 wt%. Among these solid components, the black pigment content is preferably 40 to 70 wt%, more preferably 45 to 65 wt% from the viewpoint of the optical density of the light-shielding pixel. And it is preferable to mix | blend a solvent so that these solid content components may exist in the range of 10-35 wt%.

  As the black resist coating method described above, known means such as a roll coater, curtain coater, spray coating, dip, and spin coater can be suitably used. However, a spin coater is preferred because the coating film has high uniformity. Among these, a spin coater called a cup rotation type can be applied without being affected by airflow, and is more preferable because of high uniformity of film thickness.

  The preferable conditions when coating with a cup-rotating spin coater are such that the rotation speed is 200 to 3000 rpm and the rotation time is 5 seconds to 120 seconds. Thus, after apply | coating a black resist to a transparent substrate, the prebaking process is performed in order to remove and dry the residual organic solvent in a resist film. A convection oven, a hot plate, or the like can be suitably used for pre-baking. A hot plate is more preferable because prebaking can be performed in a shorter time than a convection oven. The preferable conditions for the treatment with a hot plate are a pre-baking temperature of 50 ° C. to 150 ° C. and a pre-baking time of 15 seconds to 3 minutes. When pre-baking with a hot plate, it is possible to set a lower pre-bake temperature and pre-bake time when the glass substrate and the hot plate are in direct contact, but there is a risk that the resist exposed from the substrate will contaminate the hot plate. Therefore, proxy baking which is a processing method of pre-baking with a slight gap is more preferable.

  The black matrix is required to have a sufficient thickness for the purpose of preventing backlight leakage between the three primary color pixels. However, in the method of the present invention, the thinner the black matrix is within the range that achieves this purpose. Preferably, the resist is applied so that the film thickness of the black resist after pre-baking is 1.5 μm or less, more preferably 1.2 μm or less, and still more preferably 1.0 μm or less. Further, the film thickness variation of the black resist in the entire glass substrate is suppressed to ± 0.3 μm or less of the average film thickness, more preferably ± 0.2 μm or less, and further preferably ± 0.1 μm or less.

  Next, as for exposure, a light source that emits ultraviolet light such as a high pressure mercury lamp, an ultra high pressure mercury lamp, a xenon lamp, or a carbon arc lamp can be used, and the resist is exposed through a mask. The resin black matrix pattern drawn on the mask usually has a minimum line width of 10 to 70 μm, a longitudinal pitch of 100 to 700 μm, and a short side pitch of 50 to 300 μm.

  There are two types of exposure methods: contact exposure in which the mask and the resist film are in contact and proxy exposure in which the mask and the resist film are exposed with a slight gap. Although contact exposure provides higher resolution, proxy exposure is preferred because damage is likely to occur when the resist comes into contact with the mask and problems such as defects and dust are likely to occur. In proxy exposure, the gap width between the resist film and the mask is preferably set to 500 μm or less so that the resolution is not lowered as much as possible. Further, when the thickness of the resist film is suppressed to 1.5 μm or less, high resolution can be obtained.

  Development is performed by processing a developer that dissolves the unexposed area by a method such as dipping, spraying, or paddle. As the developer, organic solvents such as methyl ethyl ketone, acetone, and cyclohexanone can be used. However, it is not preferable from the viewpoint of environmental safety, toxicity to human body, fire risk, and the like, and an aqueous alkaline solution is preferably used as the developer. For example, organic solutions such as sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium carbonate aqueous solution, potassium carbonate, aqueous ammonia, etc., inorganic alkali aqueous solution, tetramethylammonium hydroxide aqueous solution, diethanolamine aqueous solution, triethanolamine aqueous solution, choline aqueous solution, etc. Alkaline aqueous solution etc. are mentioned.

  The alkali concentration is preferably in the range of 0.0001 wt% to 1 wt%. If the alkali concentration is out of this range, resolution is deteriorated, fringes are generated, soiling, resist damage, etc. are likely to occur. Further, when an anionic, cationic, nonionic or amphoteric surfactant is added to the alkaline developer, it is preferable to add and use it because it has the effect of improving background stains and resolution. In particular, anionic and nonionic surfactants are more preferable because of their high effects. A preferable range of addition of the surfactant is 0.0001 wt% to 2 wt%. If the amount added is small, the effect is lost, and if it is too large, it is not preferable because it becomes difficult to treat the waste liquid.

  The development temperature is preferably in the range of 15 ° C. to 30 ° C. from the viewpoint of resolution, ground stain, resist damage, and resist adhesion. Rinsing with water or the like is preferred immediately after development. If the developer is dried while remaining in the resist film, uneven color, pinholes, defects and the like are likely to occur. Drying can be performed with an air knife or an IR oven.

  Since the resin black matrix after development is not yet sufficiently cured, it is in a state where mechanical strength, chemical resistance and adhesion are insufficient, and it is preferable to perform heat curing or photocuring. Since the black matrix has poor light transmittance, it is quite difficult to uniformly cure the entire resist film by photocuring. Photocuring can be performed more rapidly than thermal curing, but it is preferable to use thermal curing from the viewpoint of uniform curing. Moreover, in the thermosetting, the same convection oven or hot plate as the pre-baking can be used, and there is an advantage in terms of manufacturing equipment.

  The temperature required for thermosetting is 150 ° C. or higher, and particularly preferably in the range of 170 ° C. to 300 ° C. If the temperature is not lower than 150 ° C., sufficient curing of the resist film cannot be expected, and further curing does not proceed even if a temperature treatment of 300 ° C. or higher is performed. The film thickness of the resin black matrix after the thermosetting is required to be 1.2 μm or less and the optical density is 2.8 or more. More preferably, the film thickness is 1.1 μm or less and the optical density is 3.0 or more. The optical density can be measured with a Macbeth densitometer.

  The pattern cross-sectional shape of the resin black matrix is preferably a vertical or forward tapered shape. If the pattern shape is inversely tapered, the film thickness becomes uneven when the three primary color resists are applied, and the film thickness difference in the three primary color pixels tends to increase. Control of the pattern shape can be achieved by optimizing the resist composition, pre-baking temperature, exposure conditions, development conditions, and thermosetting conditions.

  Next, three primary color patterns of red, green, and blue are formed based on the same method. As the color resist for forming the three primary color patterns, the same polymerizable composition as that of the black resist can be preferably used. That is, a color resist in which a pigment portion is changed to an anthraquinone pigment, a phthalocyanine pigment, an azo pigment, an isoindolinone pigment or the like in a composition comprising a binder resin, an unsaturated compound, a polymerization initiator, a pigment, and a solvent can be used.

  Suitable blending ratios are 15 to 60 wt% for the binder resin, 5 to 35 wt% for the unsaturated compound, 0.1 to 10 wt% for the polymerization initiator, and 15 to 50 wt% for the pigment. Since the color resist is applied on the unevenness of the resin black matrix, leveling performance higher than that of the black resist is required. For this reason, the blending ratio is preferably such that the ratio of the binder resin is higher than the composition ratio of the black resist and the ratio of the pigment is reduced. Furthermore, it is preferable to add a fluorine-based or silicon-based leveling agent of about 0.001 to 500 ppm because the leveling property is further improved.

  As a coating method, a cup rotating spin coater can be used, and the color resist film is dried with a hot plate or the like. The dry film thickness (film thickness of the three primary color pixels) based on the transparent substrate of the color resist film is preferably in the range of 0.5 to 2.5 μm. More preferably, it is in the range of 0.6 to 2.4 μm. If the thickness deviates from this range, the variation in the film thickness within the pixel increases due to the influence of the unevenness of the resin black matrix. In particular, at the stepped portion of the black matrix, the color resist film tends to be thicker than the surroundings, or a part where the color resist is not applied is easily formed.

  For exposure and development, exactly the same conditions as for the resin black matrix can be used. The color pattern obtained after the development is preferably formed so as to overlap the resin black matrix, and the overlapping width is 2 μm or more, more preferably 3 μm or more. If the color pattern is formed without overlapping the resin black matrix, the adhesion and chemical resistance of the resin black matrix and the color pattern are not sufficiently ensured, and the reliability tends to be lowered. The cross-sectional shape of the color pattern is preferably a forward taper. When the cross-sectional shape is vertical or inversely tapered, disconnection is likely to occur at the stepped portion when wiring such as ITO is applied on the color filter. In particular, disconnection occurs remarkably in the cross-sectional shape of the reverse taper. A method similar to that for the resin black matrix can also be used for controlling the pattern shape. The color pattern is also preferably subjected to treatment such as photocuring or heat curing after development. In the case of a color resist, since light transmittance is higher than that of the resin black matrix, photocuring can be preferably used.

  The difference between the maximum film thickness and the minimum film thickness in the pixels of the three primary colors formed by the above method is 0.6 μm or less, preferably 0.5 μm or less, and more preferably 0.4 μm or less. The film thickness difference within a pixel is the difference between the maximum value and the minimum value of the film thickness within one pixel in any of the three primary colors. In the present invention, the film thickness within such a pixel is the same. The thickness difference is substantially 0.6 μm or less for all the pixels of each color. The film thickness difference can be measured by a stylus type film thickness meter or a light interference type film thickness meter. Since the pixels formed by the pigment dispersion method are very well aligned, it is practical to confirm that the difference in film thickness is 0.6 μm or less for several pixels using these measuring devices. In other words, it was confirmed that the film thickness difference of all the pixels was 0.6 μm or less.

  As described above, the three primary color pixels are formed so as to overlap the black matrix. In many cases, the overlapping portion has the maximum film thickness and the central portion has the minimum film thickness. In the case of a color filter in which a resin black matrix is formed, the maximum film thickness of the three primary color pixels tends to be large because the black matrix is thick, but by suppressing the thickness of the black matrix by the above-described method of the present invention, the three primary color pixels The film thickness difference can be 0.6 or less.

  In this color filter, a protective film may be further formed to protect the resin black matrix and the three primary color patterns. A known resin such as an epoxy resin, an acrylic resin, or a polyimide resin can be used for the protective film. EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example, this invention is not limited to these Examples.

Synthetic acid number 200 of binder resin, molecular weight 5000 styrene / acrylic acid resin 20g, p-methoxyphenol 0.2g, dodecyltrimethylammonium chloride 0.2g, propylene glycol monomethyl ether acetate 40g were charged into a flask (3,4 epoxy cyclohexyl). ) 7.6 g of methyl acrylate was added dropwise and reacted at a temperature of 100 ° C. for 30 hours. The reaction solution was reprecipitated in water and dried to obtain a resin. When neutralization titration with KOH was performed, the acid value of the resin was 80.
Dispersion of pigment ink Black ink MA-220 (50 g) manufactured by Mitsubishi Chemical Co., Ltd. and BYK-161, 10 g of polymer dispersant BYK-Chemie Corporation are mixed with 60 g of the solvent propylene glycol monomethyl ether acetate (PGMEA) and stirred to make a mill base. It was. This mill base was dispersed by a paint shaker. The beads were made of zirconia having a particle size of 0.5 mm and dispersed at room temperature for 4 hours to obtain black ink.
2. Color ink

A mill base was prepared at the ratio shown in Table 1 and dispersed in the same manner as in 1 to obtain a color ink.
Preparation of Black Resist and Color Resist Black resist and red, green, and blue color resists were prepared using the synthesized binder resin and dispersed black and color inks in the proportions shown in Table-2.
(Example 1) 360 mm × 460 mm square, 1.1 mm plate thickness (7059 manufactured by Corning Co., Ltd.) The black resist 1 of Table-2 was applied with a cup-rotating spin coater at a rotation speed of 600 rpm and a coating time of 30 seconds. It apply | coated on the conditions of.

  This coated substrate was pre-baked with a hot plate at 80 ° C. for 60 seconds with a gap of 2 mm. It was 1.0 micrometer when the resist film thickness after drying was measured by the alpha step (made by Tencor Corporation). Next, it was exposed to 2000 mj / cm @ 2 with an exposure apparatus having a high-pressure mercury lamp through a mask. The mask used was a grid-like pattern with a black matrix line width of 30 μm, a longitudinal pitch of 350 μm, and a lateral pitch of 120 μm, on which four color filter sizes of 10.4 inches were formed.

  Development was carried out with an alkaline developing aqueous solution containing potassium hydroxide 0.01 wt%, Emulgen A-60, 0.01 wt% (non-ionic surfactant manufactured by Kao Corporation). Development was performed by spraying at a developer temperature of 23 ° C. for 30 seconds. Immediately after development, the substrate was rinsed with pure water and dried with an air knife. Thermal curing was performed in a convection oven at 250 ° C. for 30 minutes. The resist film thickness after thermosetting was 0.97 μm. Further, when the optical density was measured with a Macbeth densitometer, the OD was 3.5. Further, when the cross-sectional shape of the resist was measured by SEM, it was almost vertical.

  Next, a red resist was applied on a glass substrate on which a resin black matrix was formed with a cup rotation type spin coater under a coating rotation speed of 400 rpm and a coating time of 30 seconds. This coated substrate was pre-baked with a hot plate at 80 ° C. for 60 seconds with a gap of 2 mm. When the resist film thickness after drying was measured by α-step (manufactured by Tencor), it was 1.5 μm. Thereafter, exposure was performed at 200 mj / cm @ 2 with an exposure apparatus having a high-pressure mercury lamp through a mask. The mask used was a stripe-shaped mask with the red resist pattern edges covering the black matrix every 10 μm.

  Development was carried out with an aqueous alkaline developer solution containing 0.05 wt% potassium hydroxide, Emulgen A-60, 0.01 wt% (Kao Corporation nonionic surfactant). Development was performed by spraying at a developer temperature of 23 ° C. for 30 seconds. Immediately after development, the substrate was rinsed with pure water and dried with an air knife. Thermal curing was performed in a convection oven at 250 ° C. for 30 minutes. The maximum resist film thickness in the red pixel after thermosetting was 1.8 μm at the portion covering the resin black matrix, the minimum film thickness was 1.40 μm, and the film thickness difference was 0.4 μm. Moreover, when the cross-sectional shape of the red resist pattern was measured by SEM, it was a forward taper.

  A green resist pattern and a blue resist pattern were sequentially formed under the same conditions. The maximum resist film thickness in the green and blue pixels after thermosetting was 1.8 μm at the portion covered with the resin black matrix, the minimum film thickness was 1.40 μm, and the film thickness difference was 0.4 μm. Moreover, when the cross-sectional shape of the resist pattern was measured by SEM, both the green and blue patterns were forward tapered.

When a TFT liquid crystal display element was produced using this color filter, voltage control was easy and display quality was good.
Example 2 A resin black matrix was formed in the same manner as in Example 1 except that the coating thickness (after drying) of the black resist was 0.8 μm. The film thickness after thermosetting was 0.78 μm, and the optical density was 2.8 in OD.

The three primary color patterns were also formed in the same manner as in Example 1. As a result, the maximum resist film thickness was 1.75 μm at the portion covered with the resin black matrix, the minimum film thickness was 1.40 μm, and the film thickness difference was 0.3. It was 35 μm. Moreover, the cross-sectional shape of the resist pattern was measured by SEM.
Comparative Example 1 A resin black matrix was formed in the same manner as in Example 1 except that the black resist 2 shown in Table 2 was used and the resist film thickness was 1.7 μm.

  The resist film thickness after thermosetting was 1.65 μm, and the optical density was 3.5 in OD. Further, the cross-sectional shape of the resist pattern was vertical. Next, three primary color patterns were formed in the same manner as in Example 1. The maximum resist film thicknesses of red, green, and blue were all 2.2 μm at the portion covering the resin black matrix, the minimum film thickness was 1.40 μm, and the film thickness difference was 0.8 μm. White spots occurred in a part of the three primary color patterns near the resin black matrix. When a liquid crystal display element is produced using this color filter, voltage control is difficult, and light leakage is caused in part, resulting in poor display quality.

Claims (15)

  A color filter comprising a light-shielding pixel and three primary color pixels formed on a transparent substrate, wherein the three primary color pixels have a film thickness difference of 0.6 μm or less within the pixel.   2. The color filter according to claim 1, wherein the film thickness of the three primary color pixels is in the range of 0.5 to 2.5 [mu] m.   The color filter according to claim 1 or 2, wherein the light-shielding pixel is made of a resin containing a black pigment.   The color filter according to claim 3, wherein the black pigment of the light-shielding pixel is carbon black.   The color filter according to claim 3 or 4, wherein the light-shielding pixel is formed by a pigment dispersion method.   The color filter according to claim 1, wherein the light-shielding pixel has a film thickness of 1.2 μm or less and an optical density of 2.8 or more.   The color filter according to any one of claims 1 to 6, wherein the pixels of the three primary colors are partially overlapped with the light-shielding pixels, and the overlapping width of the light-shielding pixels and the pixels of the three primary colors is at least 2 µm or more.   In a method for producing a color filter in which a light-shielding pixel and three primary color pixels are formed on a transparent substrate, the light-shielding pixel is coated with 1) a photosensitive resin composition containing a pigment on the transparent substrate and dried. Forming a pigment-containing resin film, 2) exposing the pigment-containing resin film through a mask, and 3) developing with a liquid that dissolves an unexposed portion of the pigment-containing resin film. A method of forming a pixel, wherein a photosensitive resin composition is applied so that the thickness of the pigment-containing resin film after drying is 1.5 μm or less, and the three primary color pixels are subjected to a film thickness difference within the pixel. A method for producing a color filter, wherein the thickness is 0.6 μm or less.   The method for producing a color filter according to claim 8, wherein a photosensitive resin composition containing carbon black is applied on a transparent substrate and dried to form a light-shielding pixel.   The method for producing a color filter according to claim 8 or 9, wherein the three primary color pixels are formed on the light-shielding pixels so that the overlapping width is 2 μm or more.   The method for producing a color filter according to any one of claims 8 to 10, wherein the developer is an alkaline aqueous solution containing an anionic or nonionic surfactant.   The method for producing a color filter according to claim 8, wherein the alkali concentration of the developer is in the range of 0.0001 wt% to 1 wt% and the surfactant concentration is in the range of 0.0001 wt% to 2 wt%.   The method for producing a color filter according to any one of claims 8 to 12, wherein a treatment for curing the pigment-containing resin film by ultraviolet light or heat is performed after development.   The color filter according to claim 13, wherein the curing treatment of the pigment-containing resin film is performed by heat treatment, and the curing temperature thereof is in the range of 150 to 300 ° C.   The method for producing a color filter according to claim 8 to 14, wherein the ratio of the pigment in the solid component of the photosensitive resin composition is 40 to 70 wt%.