JP2006163233A - Color filter substrate and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color filter substrate which has an excellent color characteristic without color mixture with respect to the color filter substrate with a colored layer 3 formed by filling a color ink into an opening part of a black matrix 2 having ink repellent property, and to provide a manufacturing method of the color filter substrate. <P>SOLUTION: The black matrix 2 is formed by using a black ink consisting essentially of a black pigment, a photo-setting resin, a photoinitiator, an ink repellent agent and fine particles, wherein particle diameter of the fine particles is ≤500 nm. The content of the fine particles is ≥10 wt.% and ≤60 wt.% per the total solid content of the black ink 100 wt.%. The ink repellent agent is a fluorine-containing compound. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a color filter substrate used for a color display device and the like, and a manufacturing method thereof.

  In recent years, with the widespread use of color liquid crystal displays, there has been an increasing demand for cost reduction of color filters. At present, in the photolithography method which is the mainstream of color filter manufacturing, not only the black matrix but also a large amount of materials such as pigments are discarded in the development process of the colored layer. Furthermore, there are limits to cost reduction due to the large number of processes required for manufacturing. On the other hand, the R, G, and B colored layers can be formed at one time by the ink jet method, and there is little waste of materials such as pigments, and a significant cost reduction can be expected.

As a method for manufacturing a color filter substrate using an ink jet method, for example, methods described in Patent Documents 1, 2, 3, and the like have been proposed.
In Patent Document 1, in order to prevent the ink from spreading outside the desired colored layer region on the glass substrate, a pattern is formed by previously containing a hydrofluoric acid-based water / oil repellent in the black matrix, It describes that ink is fixed only in the colored layer region.
Patent Document 2 and Patent Document 3 describe that a black resin layer containing a fluorine-containing compound and / or a silicon-containing compound is used as a partition wall for bleeding in ink in forming a colored layer and preventing color mixing. Has been.

However, in these methods, if the amount of the water / oil repellent added is reduced, ink overflow may occur, resulting in color mixing. Conversely, when the addition amount is increased, color loss (white loss) and color unevenness in the vicinity of the black matrix may occur. For this reason, it has the fault that control of the optimal addition amount is very difficult. Further, in order to prevent ink overflow, the thickness of the black matrix needs to be considerably increased, which causes a problem in terms of cost.
JP-A-6-347637 JP-A-7-35915 JP 7-35917 A

  As described above, the prior art has drawbacks in manufacturing and cost. The present invention has been made to solve these problems, and is a color filter in which a black matrix having ink repellency is formed, and a color layer is formed by filling a color ink in an opening of the black matrix. In particular, it is an object of the present invention to provide a color filter substrate having excellent color characteristics with no color mixture. It is another object of the present invention to provide a method for manufacturing the color filter substrate.

The present invention is a color filter substrate in which a black matrix having ink repellency is formed on a transparent substrate, and a colored layer in which color ink is filled in an opening of the black matrix, the black matrix being a black pigment, A color filter substrate comprising a black matrix formed using a photocurable resin, a photoinitiator, an ink repellent agent, and a black ink mainly composed of fine particles, wherein the fine particles have a particle diameter of 500 nm or less. It is.

  The present invention also provides the color filter substrate according to the invention, wherein the content of the fine particles is 10% by weight to 60% by weight with respect to 100% by weight of the total solid content of the black ink. It is.

  The present invention also provides the color filter substrate according to the invention, wherein the ink repellent agent is a fluorine-containing compound.

  Further, according to the present invention, in the color filter substrate according to the above invention, the ink repellency of the surface layer portion of the black matrix having ink repellency is better than the ink repellency of the lower layer portion, and the contact between the surface layer portion and the color ink. A color filter substrate having an angle of 30 ° or more.

  The present invention is the color filter substrate manufacturing method according to any one of claims 1 to 4, wherein the color ink is filled by an ink jet method.

  The present invention relates to a color filter substrate in which a black matrix having ink repellency is formed on a transparent substrate, and a colored layer in which color ink is filled in an opening of the black matrix. The black matrix includes a black pigment, a photocurable resin, a light This is a black matrix formed using an initiator, an ink repellent agent, and black ink mainly composed of fine particles. Since the particle diameter of the fine particles is 500 nm or less, fine pores are formed in the black matrix, and the color A part of the solvent of the color ink can be absorbed when the ink is filled. Accordingly, there is an effect of absorbing the color ink solvent into the black matrix in addition to the ink repellent effect, and a color filter substrate with less color mixing and good patterning accuracy can be obtained.

Further, in the present invention, since the content of the fine particles is 10% by weight or more and 60% by weight or less with respect to 100% by weight of the total solid content of the black ink, the color ink solvent can be sufficiently absorbed and the film surface is brittle. Don't be.
In addition, since the ink repellent agent is a fluorine-containing compound, whitening of the color layer due to the outflow of the ink repellent agent to the opening due to bleeding out does not occur.
Further, the ink repellency of the surface layer portion of the black matrix is better than the ink repellency of the lower layer portion, and the contact angle between the surface layer portion and the color ink is 30 ° or more, so the pixel flatness of the colored layer is improved.

  Further, according to the present invention, since the color ink is filled by an ink jet method, a color filter substrate manufacturing method capable of providing a color filter substrate with high patterning accuracy and excellent color characteristics at a low cost is provided.

Hereinafter, the present invention will be described based on embodiments.
FIG. 1 is a cross-sectional view of an embodiment of a color filter substrate according to the present invention. The color filter substrate shown in FIG. 1 forms a black matrix 2 on a transparent substrate 1 and then colors the openings of the black matrix 2 with red (R), green (G), and blue (B) color inks. The layer 3 is formed, and the protective layer 4 in the present invention is further provided. At this time, the colored layer can be formed easily and inexpensively by forming R, G, and B by an inkjet method. Moreover, by providing the protective layer 4, a color filter substrate excellent in smoothness and various resistances can be obtained.

  As the transparent substrate 1 in the present invention, a glass substrate, a quartz substrate, a plastic substrate or the like can be used. In particular, when a glass substrate is used, a color filter substrate having not only excellent transparency but also excellent strength, heat resistance, and weather resistance can be obtained.

  The black matrix 2 in the present invention is preferably formed by applying a black ink composed of a black pigment, a photocurable resin, a photoinitiator, an ink repellent agent, fine particles, a solvent, etc. on a transparent substrate and photolithography. Thereby, a color filter substrate having excellent light shielding properties can be obtained. Further, the addition of the ink repellent agent can prevent the color ink from flowing out to adjacent pixels of different colors, thereby preventing color mixing. Further, by adding fine particles, pores are formed in the black matrix, and the solvent can be absorbed. For this reason, color mixing can be prevented even when a large amount of color ink is filled.

  The photocurable resin in the present invention is not particularly limited, but a resin that is easily cured by a photolithography method is selected depending on the combination with the photoinitiator. For example, aliphatic acrylate, alicyclic acrylate, aromatic acrylate, functional group-containing acrylate containing OH group, allyl group, glycidyl group, carboxyl group, chromo group, bromo group, etc., phosphorus acrylate, metal acrylate, etc. Resin monomers or oligomers can be used. Alternatively, a methacrylate having the same skeleton as the acrylate can also be used. Furthermore, monomers or oligomers such as pyrrolidone and vinyl acetate can be used.

The photoinitiator is not particularly limited, and a common photoinitiator such as azoisobutyronitrile can be used.
As the black pigment, a general pigment such as an organic black pigment or an inorganic black pigment can be used.

  The ink repellent agent in the present invention is added in order to prevent intrusion into adjacent pixels with the black matrix as a boundary when filling with color ink. As the ink repellent agent, a silicone type or a fluorine type is typically used. Specific examples of the ink repellent agent include silicone resins and silicone rubbers containing a siloxane component, and also fluorine resins such as vinylidene fluoride, vinyl fluoride, ethylene trifluoride, and copolymers thereof. However, it is not limited to these.

  By using an ink repellent agent, bleeding may occur during heating in the production process. Due to the bleed-out of the ink repellent agent, the ink repellent agent adheres to the transparent substrate in the opening, and color loss or the like occurs when the color ink is filled. In order to prevent bleeding out, it is particularly preferable to use a fluorine-containing compound as the ink repellent agent. For example, a fluorine resin having a fluoroalkyl group in the main chain or side chain. Furthermore, it can prevent more effectively by using an oligomer type thing rather than a low molecular weight thing.

As the fine particles in the present invention, both inorganic fine particles, organic fine particles, and organic-inorganic composite fine particles can be used. The particle diameter is 500 nm or less. Here, the particle diameter is a primary or secondary particle diameter.
When the particle diameter exceeds 500 nm, the size of the pores between the fine particles increases, and when a pigment is used as a color ink pigment, the color ink pigment penetrates into the black matrix, resulting in a larger amount of color ink. Must be filled.

The lower limit of the particle diameter is 5 nm or more, more preferably 10 nm or more. When the particle diameter is less than or equal to the lower limit value, the pores between the fine particles become small and the solvent of the color ink is difficult to absorb.

  When the content of the fine particles is less than 10% by weight with respect to 100% by weight of the total solid content of the black ink, pores are not formed in the black matrix, so that the color ink solvent cannot be sufficiently absorbed. On the other hand, if it exceeds 60% by weight, the film surface becomes brittle, which is not preferable. The total solid content is preferably 10% by weight or more and 60% by weight or less. The optimum content varies depending on the type and particle size of the fine particles, but is more preferably 40% by weight or more and 50% by weight or less.

Further, when color ink is injected between the black matrices, in order to reduce the color mixture between adjacent color patterns, the contact angle of the color ink is set to 30 ° or more with respect to the surface portion of the black matrix. It is preferable to do. A contact angle of 35 ° or more is preferable because the flatness of the colored layer is improved. More preferably, it is 40 ° or more. When the angle is 40 ° or more, even when the color ink is filled at a high speed at a time, the occurrence of color mixture in adjacent pixels is very small.
When the contact angle is lower than 30 °, color mixture with adjacent color patterns is likely to occur, which causes a decrease in yield (see FIG. 2).

The method for making the ink repellency of the black matrix surface layer better than the ink repellency of the lower part is not particularly limited. For example, a good solvent and a poor solvent having different solubility of the ink repellent agent are prepared, and at that time, a solvent having a boiling point higher than that of the good solvent is selected. These two solvents are mixed to form a solvent for the black matrix composition.
When forming a black matrix using this black matrix composition, if the coating film is dried under certain conditions, it evaporates from a good solvent with a low boiling point, so that the ink repellent agent is unevenly distributed on the surface or top surface with evaporation. Will do.

  As described above, the ink repellency of the surface portion of the black matrix can be made better than the ink repellency of the lower portion. It can be realized by mixing the good solvent and the poor solvent so that the contact angle of the color ink with respect to the black matrix surface layer portion is 30 ° or more.

  The material of the color ink used for the colored layer 3 includes a colorant, a resin, a dispersant, a solvent, and the like. Although both pigments and dyes can be used as the colorant, it is preferable to use a pigment from the viewpoint of excellent weather resistance. Here, specific examples of the pigment used as the colorant include PigmentRed 9, 19, 38, 43, 97, 122, 123, 144, 149, 166, 168, 177, 179, 180, 192, 215, 216, 208. 216, 217, 220, 223, 224, 226, 227, 228, 240, PigmentBlue 15, 15: 6, 16, 22, 29, 60, 64, PigmentGreen 7, 36, PigmentRed 20, 24, 86, 81, 83, 93 , 108, 109, 110, 117, 125, 137, 138, 139, 147, 148, 153, 154, 166, 168, 185, Pigment Orange 36, Pigment Violet 23, etc., but is not limited thereto.

  Furthermore, these may be used in combination of two or more in order to obtain the desired hue. Examples of the resin include casein, gelatin, polyvinyl alcohol, carboxymethyl acetal, polyimide resin, acrylic resin, epoxy resin, melanin resin, and the like, which are appropriately selected in relation to the colorant. An acrylic resin is preferred when heat resistance and light resistance are required.

In order to improve the dispersion of the colorant in the resin, a dispersant may be used. As the dispersant, as the nonionic surfactant, for example, polyoxyethylene alkyl ether and the like, and ionic surfactant Examples thereof include sodium alkylbenzene sulfonate, poly fatty acid salt, fatty acid salt alkyl phosphate, tetraalkyl ammonium salt, and other organic pigment derivatives and polyesters. One type of dispersant may be used alone, or two or more types of dispersants may be mixed and used.

  An ink jet method is optimal for forming the colored layer 3 in the present invention. As the ink jet device to be used, there are a piezo conversion method and a heat conversion method depending on the ink discharge method, and the piezo conversion method is particularly preferable. A device in which the ink particleization frequency is about 5 to 100 kHz, the nozzle diameter is about 5 to 80 μm, three heads are arranged, and 60 to 500 nozzles are incorporated in one head is suitable. Moreover, drying and UV hardening can also be performed as needed.

  The color ink for forming the colored layer 3 by the ink jet method is preferably adjusted to have an appropriate surface tension range of 35 mN / m or less and a boiling point of 130 ° C. or higher in the ink jet method. 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.

  The surface tension and boiling point can be adjusted with a solvent. Specific examples of the solvent used include 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2-ethoxyethyl acetate, and 2-butoxyethyl. Acetate, 2-methoxyethyl acetate, 2-ethoxyethyl ether, 2- (2-ethoxyethoxy) ethanol, 2- (2-butoxyethoxy) ethanol, 2- (2-ethoxyethoxy) ethyl acetate, 2- (2- Examples include butoxyethoxy) ethyl acetate, 2-phenoxyethanol, diethylene glycol dimethyl ether, and the like, but are not limited thereto. Further, two or more kinds of solvents may be mixed and used as necessary, but are appropriately selected in consideration of solubility.

  The color filter substrate of the present invention can be provided with a protective layer 4 as the uppermost layer as necessary. The protective layer is preferably formed of a transparent resin film. This improves surface smoothness and weather resistance.

Examples of the present invention will be specifically described below.
(Create black matrix)
10 parts by weight of a polyimide precursor (Toray Industries, Inc .: Semicofine SP-510), 7.5 parts by weight of carbon black, 130 parts by weight of NMP, 5 parts by weight of a dispersant (copper phthalocyanine derivative), 5 parts by weight of an initiator triazine, 0.1 part by weight of perfluoroalkyl group-containing oligomer was dispersed for 3 hours while cooling with a bead mill disperser.

  Separately, dry silica (manufactured by Nippon Aerosil Co., Ltd .: secondary particle size: 300 nm) is dispersed as a fine particle in a solvent so that the silica solid content is 20% by weight with respect to 100% by weight of the solid content of the dispersion. In addition, a black matrix composition was prepared by dispersing for a second time with a bead mill disperser. This black matrix composition was formed on a non-alkali glass substrate (product number 1713, manufactured by Corning) using a spin coater to form a coating film of about 1.5 μm. A black matrix was formed by heat curing at 100 ° C. for 20 minutes.

(Preparation of color 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. 19.0 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 color inks.

(Production of color filter substrate)
A red (R), green color is produced by an inkjet printing apparatus using a color ink of each color of R, G, B, and a 12 pl, 180 dpi head (manufactured by Seiko Instruments Inc.) at the opening of the black matrix on the glass substrate. (G) and blue (B) Each of the patterned colored layers 3 was formed.

  The color filter substrate thus obtained was a color filter substrate having no color mixing, excellent density balance, a clear pixel shape, and a sharp pixel edge.

(Create black matrix)
It was prepared in the same manner as in Example 1 except that colloidal silica (manufactured by Nissan Chemical Co., Ltd .: particle diameter 40 nm) was used as the fine particles.
(Preparation of color ink)
Preparation was carried out in the same manner as in Example 1.
(Production of color filter substrate)
A red (R), green color is produced by an inkjet printing apparatus using a color ink of each color of R, G, B, and a 12 pl, 180 dpi head (manufactured by Seiko Instruments Inc.) at the opening of the black matrix on the glass substrate. (G) and blue (B) Each of the patterned colored layers 3 was formed.
The color filter substrate thus obtained was a color filter substrate having no color mixing, excellent density balance, a clear pixel shape of the color filter substrate, and a sharp pixel edge.

<Comparative Example 1>
(Create black matrix)
10 parts by weight of a polyimide precursor (manufactured by Toray Industries, Inc .: “Semicofine SP-510”), 7.5 parts by weight of carbon black, 130 parts by weight of NMP, 5 parts by weight of a dispersant (copper phthalocyanine derivative), 5 parts by weight of triazine initiator The portion was dispersed for 3 hours while cooling with a bead mill disperser to prepare a black matrix composition. The black matrix composition was formed on a non-alkali glass substrate (manufactured by Corning: product number 1737) with a spin coater to a coating thickness of about 1.5 μm. A black matrix was formed by heat curing at 100 ° C. for 20 minutes.

(Preparation of color ink)
Preparation was carried out in the same manner as in Example 1.
(Production of color filter substrate)
A red (R), green color is produced by an inkjet printing apparatus using a color ink of each color of R, G, B, and a 12 pl, 180 dpi head (manufactured by Seiko Instruments Inc.) at the opening of the black matrix on the glass substrate. (G) and blue (B) Each of the patterned colored layers 3 was formed.
In the color filter substrate thus obtained, a partial color mixture was observed.

  As an application example of the color filter substrate obtained in the present invention, it can be used as a color filter substrate for liquid crystal display, electronic paper, or white EL. The production of the color filter substrate according to the present invention can be performed inexpensively and easily, and the color filter substrate can be used for a small lot.

It is sectional drawing of one Example of the color filter board | substrate of this invention. It is explanatory drawing of the contact angle of color ink.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transparent substrate 2 ... Black matrix 3 ... Colored layer 4 ... Protective layer

Claims (5)

  A color filter substrate in which a black matrix having ink repellency is formed on a transparent substrate, and a colored layer in which color ink is filled in an opening of the black matrix is sequentially formed. The black matrix includes a black pigment and a photocurable resin. A color filter substrate comprising: a black matrix formed using a photoinitiator, an ink repellent agent, and a black ink containing fine particles as a main component, and the particle diameter of the fine particles is 500 nm or less.   The color filter substrate according to claim 1, wherein the content of the fine particles is 10 wt% or more and 60 wt% or less with respect to 100 wt% of the total solid content of the black ink.   The color filter substrate according to claim 1, wherein the ink repellent agent is a fluorine-containing compound.   The ink repellency of the surface layer portion of the black matrix having ink repellency is better than the ink repellency of the lower layer portion, and the contact angle between the surface layer portion and the color ink is 30 ° or more. The color filter substrate according to claim 1, claim 2, or claim 3.   The color filter substrate according to any one of claims 1 to 4, wherein the color ink is filled by an ink jet method.

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