JP2005173324A - Method of manufacturing color filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a color filter which prevents color mixture between adjacent pixels and forms pixels free from voids and unevenness of color within pixel areas surrounded with partitions when giving ink into the pixel areas. <P>SOLUTION: When curing ink is given to aperture parts of a black matrix 2 by an ink jet system and is hardened to form colored parts, the curing ink is given by the ink jet system after the surface of a transparent substrate 1 in the aperture parts of the black matrix and black matrix side walls are preliminarily made ink-philic. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a color filter for a display device such as an electrolytic emission display device, a fluorescent display device, a plasma display, and a liquid crystal display device, and more particularly to a method for manufacturing a color filter using an inkjet method.

  In recent years, a method for manufacturing a color filter using an ink jet method has been studied mainly for the purpose of cost reduction.

  As a method of manufacturing a color filter using an inkjet method, a method of forming a black matrix on a glass substrate and applying ink to the opening of the black matrix using an inkjet recording apparatus to form colored pixels has been proposed. Yes. Furthermore, in this method, as a constituent material of the black matrix, the ink is not easily wetted and repels the ink so that the ink is satisfactorily filled in the predetermined opening and the mixed color is not generated between the adjacent colored pixels. Easy things are being considered.

  For example, as a method for preventing color mixture between colored pixels, there is a method of forming a large ink-repellent silicone rubber pattern having the same size as the black matrix on the black matrix to prevent color mixture in the ink jet method or the printing method ( Patent Document 1).

  However, the above-described method multiplies the partition walls, and it is necessary to perform the photolithography process a plurality of times. Therefore, there is a problem that the process is complicated, the cost is increased, and the yield is lowered.

  As another method, there has been proposed a method in which a black matrix is formed using a material having a contact angle of 20 ° or more with respect to ink, and ink is applied to the opening (see Patent Document 2). Further, as a black matrix material, a material having a contact angle of 40 ° or more with respect to water has been proposed (see Patent Document 3).

  Furthermore, the critical surface tension of each material of the substrate, ink, and black matrix is substrate surface> ink> black matrix surface, black matrix surface <35 dyne / cm, substrate surface ≧ 35 dyne / cm, and ink is 5 dyne / cm or more from both It has been proposed to set so as to have a difference (see Patent Document 4). In these examples, as a material for the black matrix, any of the methods includes a water repellent such as a fluorine compound or a silicon compound in order to provide ink repellency.

However, if the black matrix contains a fluorine compound or silicon compound, which is a water repellent, as in the above method, the black matrix material is not treated during post-baking (main curing), which is the final step of the black matrix formation process. The water repellent agent evaporates and adheres thinly to the glass substrate surface exposed at the black matrix opening. Even when no water repellent is used, the low-molecular organic substance in the black matrix material evaporates and adheres to the glass substrate surface in the same manner. In either case, the glass substrate surface exhibits ink repellency, and when ink is applied to the openings of the black matrix, the adhesion between the glass substrate surface and the ink deteriorates, and the ink is uniformly distributed in the openings. There is a risk that white spots and color unevenness occur.
JP 4-123005 A JP 7-35917 A JP-A-7-35915 JP-A-6-347637

  The present invention prevents color mixing between adjacent pixels when applying ink to a pixel region surrounded by a partition wall in a method for manufacturing a color filter that is inexpensively manufactured by a simple process using an inkjet method. In addition, it is an object of the present invention to provide a method for manufacturing a color filter capable of forming pixels without white spots and color unevenness in a region.

  The present invention relates to a method for producing a color filter having at least a resin black matrix on a transparent substrate and colored pixels formed in the openings of the black matrix, wherein the curable ink is applied to the openings of the black matrix by an inkjet method. When the colored pixels are formed by curing the curable ink, a film is formed in advance on at least the opening of the black matrix, and the transparent substrate surface and the black matrix side wall of the opening are made ink-philic. Thereafter, a curable ink is applied by an ink jet method.

  The present invention also provides the method for producing a color filter according to the above invention, wherein the coating is made of a transparent resin.

  In the color filter manufacturing method according to the present invention, the coating liquid obtained by diluting the transparent resin with a solvent has good wettability with respect to the black matrix, and the solid content is the total weight of the coating liquid. The color filter manufacturing method is characterized by being 5% by weight or less with respect to 100%.

  The present invention is also the color filter manufacturing method according to the above invention, wherein the coating film is made of a coupling agent.

  The present invention is also the color filter manufacturing method according to the above invention, wherein the black matrix exhibits ink repellency.

  The present invention is also the color filter manufacturing method according to the invention, wherein the transparent resin or the coupling agent is applied to the black matrix opening by an ink jet method.

  According to the present invention, by covering the black matrix opening, that is, the glass substrate surface and the black matrix side wall with an ink-philic transparent resin thin film, wetting and spreading of the ink in the region is improved, and the ink film thickness is increased. A color filter having colored pixels that are uniform, have no white spots, and have an excellent density balance can be provided.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a process diagram illustrating a method for manufacturing a color filter according to the present invention. FIG. 1A shows a state in which a black matrix 2 is formed on a transparent substrate 1. First, the ink-philic film 3 covering the opening of the black matrix 2, that is, the transparent substrate surface and the black matrix side surface is formed (FIG. 1B). Next, red (R), green (G), and blue (B) colored inks 4 are ejected to the openings covered with this film by the ink jet method (FIG. 1 (c)), and the ink is dried and cured. After that, a color filter is obtained (FIG. 1 (d)).

  Although the glass substrate is generally used as the transparent substrate 1 used in the present invention, it should satisfy the characteristics required for the final use such as a liquid crystal display device, for example, transparency, mechanical strength, etc., and can withstand subsequent processes. For example, a plastic substrate such as PET, PES, and PEN can be used.

  The black matrix 2 in the present invention uses a black photosensitive resin composition mainly composed of a resin (including a photopolymerizable monomer and a photopolymerization initiator), a black light shielding material, a dispersant, a solvent, and the like, and is patterned by a photolithography method. To form. Further, the method for forming the black matrix 2 is not limited to the photolithography method, and for example, it can be formed by a thermal transfer method or the like.

  The black light shielding material of the black matrix 2 in the present invention includes black pigments, black dyes, inorganic materials, etc., which are used by mixing organic pigments, carbon black, aniline black, graphite, titanium oxide, iron black and the like. is there.

  In addition, as the dispersant for the black matrix 2 in the present invention, for nonionic surfactants, for example, polyoxyethylene alkyl ether and the like, and for ionic surfactants, for example, sodium alkylbenzenesulfonate, poly fatty acid salt In addition, fatty acid salt alkyl phosphates, tetraalkylammonium salts, and the like, organic pigment derivatives, polyesters, and the like. A dispersing agent may be used independently and may mix and use two or more types.

  In addition, the solvent for the black matrix 2 in the present invention is appropriately selected and used from the viewpoints of coating properties and dispersion stability of the black resin composition, and includes toluene, xylene, ethyl cellosolve, ethyl cellosolve acetate. , Diclime, cyclohexanone and the like.

  Further, it is desirable to add an ink repellent component to the black matrix 2 to enhance the ink repellency. Specific examples include organic silicones in the main chain or side chain, silicone resins and silicone rubbers containing a siloxane component, vinylidene fluoride, vinyl fluoride, ethylene trifluoride, etc. However, the present invention is not limited to these.

  By imparting ink repellency to the black matrix 2, it is possible to prevent the ink from overflowing beyond the black matrix serving as the partition wall, and to prevent color mixing between adjacent colored pixels.

  In general, when ink repellency is imparted to a black matrix, the ink does not diffuse sufficiently due to side wall ink repellency or contamination of the opening (white spots), and the film thickness after drying is not uniform in the region. Color unevenness may be caused. However, according to the present invention, all the openings of the black matrix are covered with the ink-philic film, so that the ink is sufficiently diffused, the ink film thickness in the region is uniform, and good pixels are obtained. is there.

  Furthermore, in order to completely prevent ink color mixing, it is effective not only to increase the ink repellency of the black matrix 2 itself that becomes the partition walls, but also to increase the thickness of the partition walls. Therefore, the thickness of the partition wall is desirably 1 μm or more.

  One of the ink-philic coating materials in the present invention is to use a transparent resin.

  FIG. 2A is a schematic cross-sectional view for explaining a first example in a state where the ink-philic film 3 is formed of a transparent resin in the black matrix opening. FIG. 2B is a schematic cross-sectional view illustrating the second example.

  FIG. 2A is a diagram showing a case where a transparent resin coating solution having poor wettability is used for the black matrix. When the wettability of both is not good, the dried transparent resin becomes a lens shape without covering the opening. On the other hand, when a transparent resin coating liquid having good wettability with respect to the transparent substrate surface and the black matrix side wall is used, the transparent resin forms a film covering the black matrix opening as shown in FIG. To do. Therefore, it is desirable that the transparent resin coating liquid has good wettability with respect to the black matrix.

  Furthermore, considering that the pixels are formed by applying ink to the black matrix opening covered with the thin film made of the transparent resin, the thin film should be thin. That is, the solid content is desirably 5% by weight or less. If it is 5% by weight or more, because of the thickness of the thin film, when ink is applied to the opening, the height of the pixel may exceed the height of the partition wall, and the overall flatness is deteriorated.

  As a coating method of the transparent resin coating liquid, an inkjet method, a printing method, a spin coating method, or the like can be used. In any coating method, the upper surface of the black matrix is ink repellant, so that the resin is satisfactorily filled into the predetermined opening. Further, since the upper surface of the black matrix is not covered with a transparent resin, the ink repellency of the upper surface is not impaired, and therefore, color mixture is prevented even when colored ink is ejected by the ink jet method.

  As the transparent resin in the present invention, casein, gelatin, polyvinyl alcohol, carboxymethyl acetal, polyimide resin, acrylic resin, epoxy resin, melanin resin and the like are used, and in particular, have a contact angle of 20 ° or less with respect to the colored ink. A transparent resin is preferred. These transparent resins are cured mainly by thermal energy.

  Examples of the solvent species for diluting the transparent resin in the present invention include, when the coating method is a printing method or a spin coating method, for example, toluene, xylene, ethyl cellosolve, ethyl cellosolve acetate, diclime, cyclohexanone, and the like. However, it is used by appropriately selecting from coating properties, dispersion stability, and the like.

  In addition, when the transparent resin coating liquid is applied by an ink jet method, a suitable surface tension range in ink jet printing is preferably 35 mN / m or less and a boiling point of 130 ° C. or more. When the surface tension is 35 mN / m or more, the dot shape stability at the time of ink jet discharge is significantly adversely affected. When the boiling point is 130 ° C. or less, the drying property in the vicinity of the nozzle is remarkably increased. This is not preferable because it causes clogging and other defects.

Specifically, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-methoxyethyl acetate, 2-ethoxyethyl ether, 2- (2-ethoxy Ethoxy) ethanol, 2- (2-butoxyethoxy) ethanol, 2- (2-ethoxyethoxy) ethyl acetate, 2- (2-butoxyethoxy) ethyl acetate, 2-phenoxyethanol, diethylene glycol dimethyl ether, etc. The solvent is not limited to these, and any solvent that satisfies the above requirements can be used. Moreover, you may mix and use 2 or more types of solvents as needed.

  In addition, the material for forming the ink-philic film in the present invention is not necessarily made of a transparent resin. For example, silane coupling agents such as vinyl silane coupling agents, epoxy silane coupling agents, methacrylic silane coupling agents, amino silane coupling agents, mercapto silane coupling agents, sulfide silane coupling agents, etc. You may form a film in an opening part using a titanate type, an aluminate type, and a chromium type coupling agent.

  For example, when a silane coupling agent is applied to the substrate, the wettability with the ink is increased because the lipophilic group is on the surface layer on the glass substrate surface. On the other hand, since the hydrophilic group is on the surface layer on the resin black matrix surface, the wettability with the ink is lowered. By this effect, the ink spreads uniformly at the black matrix opening, and a good pixel can be obtained.

  The material of the colored ink in the present invention is mainly composed of a pigment, a resin, and a solvent. As the pigment, a dye or a pigment is used. As the resin, casein, gelatin, polyvinyl alcohol, carboxymethyl acetal, polyimide resin, acrylic resin, epoxy resin, melanin resin and the like are used, and are appropriately selected in relation to the pigment. When heat resistance and light resistance are required, an acrylic resin is preferable.

  As the solvent species used for the colored ink, those having a surface tension range suitable for inkjet printing of 35 mN / m or less and a boiling point of 130 ° C. or more are preferable. When the surface tension is 35 mN / m or more, the dot shape stability at the time of ink jet discharge is significantly adversely affected. When the boiling point is 130 ° C. or less, the drying property in the vicinity of the nozzle is remarkably increased. This is not preferable because it causes clogging and other defects.

  Specifically, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-methoxyethyl acetate, 2-ethoxyethyl ether, 2- (2-ethoxy Ethoxy) ethanol, 2- (2-butoxyethoxy) ethanol, 2- (2-ethoxyethoxy) ethyl acetate, 2- (2-butoxyethoxy) ethyl acetate, 2-phenoxyethanol, diethylene glycol dimethyl ether, etc. The solvent is not limited to these, and any solvent that satisfies the above requirements can be used. Further, if necessary, two or more kinds of solvents may be mixed and used.

  In addition, a dispersant may be used to improve the dispersion of the dye in the resin. As the dispersant, for example, a nonionic surfactant, for example, polyoxyethylene alkyl ether, or an ionic surfactant, For example, sodium alkylbenzene sulfonate, polyfatty acid salt, fatty acid salt alkyl phosphate, tetraalkylammonium salt, and other organic pigment derivatives, polyester, and the like. A dispersing agent may be used independently and may mix and use two or more types. As the solvent, in addition to solubility, stability over time, drying property, and the like are required, and the solvent is appropriately selected in relation to the dye and the resin.

  In addition, the color filter formed according to the present invention can be cured by energy such as heat, light, or electron beam for the purpose of improving the durability after the pixels are formed.

Examples of the present invention will be specifically described below.
(Formation of black matrix)
Resist material containing carbon black on alkali-free glass (Corning “# 1737”) (negative resist ink for black matrix “V-259 BK739P” manufactured by Nippon Steel Chemical Co., Ltd.) and dimethylpolysilane as a photosensitive silicon compound Was added by spin coating so that the film thickness became 1.5 μm, and prebaked. Thereafter, exposure, development, and post-baking were performed to form a black matrix.
(Preparation and application of ink-repellent transparent resin solution)
20 parts of methacrylic acid, 10 parts of methyl methacrylate, 55 parts of butyl methacrylate and 15 parts of hydroxyethyl methacrylate are dissolved in 300 g of butyl lactate, and 0.75 part of azobisisobutylnitrile is added in a nitrogen atmosphere, and the reaction is carried out at 70 ° C. for 5 hours. As a result, an acrylic copolymer resin was obtained. The obtained acrylic copolymer resin was diluted with propylene glycol monomethyl ether acetate so that the resin concentration was 5% by weight, and a diluted solution of acrylic copolymer resin having a viscosity of 10 cps was obtained.

The acrylic copolymer resin diluent was applied to the opening of the black matrix by an ink jet printing apparatus equipped with a 12 pl, 180 dpi head. The film was dried at 200 ° C. for 30 minutes to obtain a thin film of an ink-philic transparent resin covering the black matrix opening and side surfaces.
(Preparation of colored ink)
20 parts of methacrylic acid, 10 parts of methyl methacrylate, 55 parts of butyl methacrylate and 15 parts of hydroxyethyl methacrylate are dissolved in 300 g of butyl lactate, and 0.75 part of azobisisobutylnitrile is added in a nitrogen atmosphere, and the reaction is carried out at 70 ° C. for 5 hours. As a result, an acrylic copolymer resin was obtained. The obtained acrylic copolymer resin was diluted with propylene glycol monomethyl ether acetate so that the resin concentration would be 10% to obtain a diluted solution of the acrylic copolymer resin. 19.9 g of pigment and 0.9 g of dispersant were added to 80.1 g of this diluted solution, and kneaded with three rolls to obtain red, green and blue colored varnishes. Each colored varnish was adjusted with propylene glycol monomethyl ether acetate so that the pigment concentration was 12 to 15% and the viscosity was 15 cps to obtain R, G and B colored inks.
(Production of color filter)
The above-described colored inks of R, G, and B are used for the black matrix opening in which the glass substrate surface of the opening and the black matrix side wall are covered with a transparent resin thin film having ink affinity, and a 12 pl, 180 dpi head is used. Red (R), green (G), and blue (B) colored pixels were formed by the mounted inkjet printing apparatus.

When the color filter thus prepared was observed, no color mixing was confirmed. In addition, each pixel has a good and highly reliable color filter in which the ink is uniformly spread in the region, the film thickness is uniform, and the color difference is ΔE _ab 3 or less.

In the step of applying the ink-philic transparent resin of Example 1, the transparent resin was applied by spin coating. All other operations were performed in the same manner as in Example 1. When the color filter thus prepared was observed, no color mixing was confirmed. In addition, each pixel has a good and highly reliable color filter in which the ink is uniformly spread in the region, the film thickness is uniform, and the color difference is ΔE _ab 3 or less.

  Without applying the ink-philic transparent resin of Example 1, the colored ink was directly applied to the black matrix opening by an ink jet printer.

When the color filter thus prepared was observed, no color mixture was confirmed, but there was a portion where the ink did not spread uniformly in the region. Further, since the ink film thickness was reduced at the boundary surface with the side surface of the black matrix, the color unevenness was large, and the color difference was ΔE _ab 10 or more.

It is explanatory drawing of one Embodiment of the manufacturing method of the color filter concerning this invention. It is explanatory drawing which showed the difference in the shape after drying by the wettability of the ink-philic film concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transparent substrate 2 ... Black matrix 3 ... Ink affinity film 4 ... Ink 5 ... Colored pixel

Claims (6)

  In a method for producing a color filter having at least a resin black matrix on a transparent substrate and colored pixels formed in the openings of the black matrix, a curable ink is applied to the openings of the black matrix by an inkjet method, When the colored ink is formed by curing the curable ink, an ink jet method is used after forming a film at least in the opening of the black matrix and making the surface of the transparent substrate and the side wall of the black matrix ink-philic. A method for producing a color filter, characterized in that a curable ink is applied.   The method for manufacturing a color filter according to claim 1, wherein the coating is made of a transparent resin.   The coating liquid obtained by diluting the transparent resin with a solvent has good wettability with respect to the black matrix, and the solid content is 5% by weight or less based on 100% of the total weight of the coating liquid. Item 3. A method for producing a color filter according to Item 2.   The method for producing a color filter according to claim 1, wherein the coating is made of a coupling agent.   The method for producing a color filter according to claim 1, 2, 3, or 4, wherein the black matrix exhibits ink repellency.   The method for producing a color filter according to claim 2, wherein the transparent resin or the coupling agent is applied to the black matrix opening by an inkjet method.

Images