JP2004325617A - Color filter base plate and color filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reliable optical device with good yield by solving a peculiar problem such as color mixture, void and irregular color in inexpensively manufacturing a color filter in simple process utilizing an ink jet system. <P>SOLUTION: The color filter which has at least a black matrix 2 on a light transmissive base plate 1, and where colored parts 4 and 5 are formed on the aperture part of a black matrix by an ink jet method has a partition 3 whose width is smaller than the black matrix on the black matrix. It is desirable that relation between the line width (x) of the black matrix and the width (y) of the partition on the black matrix satisfies 0.2x≤y≤0.8x and the partition is made ink repellent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a color filter substrate and a color filter for a display device such as a field emission display device, a fluorescent display device, a plasma display (PDP) and a liquid crystal display device, and more particularly to a color used in a manufacturing method using an ink jet method. It relates to a filter substrate.
[0002]
[Prior art]
In recent years, a color filter manufacturing method using an ink jet method has been studied mainly for the purpose of cost reduction. However, when a color filter is created by the ink jet system, there are problems specific to the ink jet system, such as “mixed colors”, “white spots”, and “color unevenness”.
[0003]
In a method of manufacturing a color filter in which a black matrix is used as a partition and a colored portion is formed by applying ink to an opening of the black matrix, the volume of the black matrix is several times to several tens times the volume of the opening of the black matrix. Need to be applied. If the solid content concentration of the coloring agent and the curing component contained in the ink is high, that is, if the volume of the ink to be applied is relatively small, the black matrix sufficiently functions as a partition, and the inside of the opening of the black matrix Can hold ink. Therefore, the applied ink does not cross the black matrix and reach the adjacent colored portions of different colors.
[0004]
However, in order to discharge the ink more stably from the ink jet head nozzle, it is necessary to lower the viscosity, that is, it is necessary to lower the solid content concentration in the ink. In this case, it is necessary to apply a large amount of ink to form pixels. At this time, since the ink overflows beyond the black matrix serving as a partition, "color mixing" occurs between adjacent colored portions.
[0005]
Therefore, as a method of preventing color mixture between color filters, there is a method of forming a silicone rubber pattern having a large ink repellency having substantially the same size as the black matrix on the black matrix to prevent color mixture in the ink jet method or the printing method. (For example, see Patent Document 1).
[0006]
However, as a method of forming a silicone rubber pattern, the silicone rubber layer is formed on the photosensitive resin layer, and then the silicone rubber layer or the silicone rubber layer and the photosensitive resin layer are removed by photolithography. A process is required, and the number of manufacturing processes increases.
[0007]
Therefore, as a method for obtaining a black matrix having an ink-repellent (water-repellent or oil-repellent in some cases) surface by a simpler method, a light-transmitting photosensitive material containing silicone fine particles is formed on a black matrix forming member. There is a method of forming a resin layer, patterning the photosensitive resin layer by a photolithography process, and then processing a black matrix forming member using the patterned photosensitive resin layer as a mask (for example, see Patent Document 2).
[0008]
However, in this proposal, since silicone is contained in the photosensitive resin in the form of fine particles, the fine particles of silicone are left undeveloped, and this is transferred to the black matrix forming member, and the amount of the fine silicone particles that generate defects in the black matrix is reduced. If the content is increased, the resolution is reduced, and the amount of the silicone fine particles that are not suitable for forming a fine pattern is limited. Therefore, it is difficult to obtain high ink repellency.
[0009]
In recent years, in color filters for TFT-type liquid crystal elements, the opening shape of the black matrix has become complicated for the purpose of protecting the TFT from external light or for obtaining a bright display by increasing the aperture ratio. ing. Therefore, a plurality of corners are provided, and there is a problem that the ink is not sufficiently diffused into the corners. In forming a black matrix, a photolithography process using a resist is generally used. Contaminants may adhere to the surface of the transparent substrate due to various components contained in the resist, and may hinder the diffusion of the ink.
[0010]
This is a problem called “white spots”. The white spots cause display defects such as color unevenness and reduced contrast.
[0011]
Also, if the ink repellency of the side of the black matrix is extremely high compared to the surface of the transparent substrate, the ink is repelled on the side of the black matrix, and the ink is not sufficiently diffused in the area. In some cases, a problem occurs in that the color becomes lighter at a portion where the ink and the black matrix are in contact with each other.
[0012]
[Patent Document 1]
JP-A-4-123005 [Patent Document 2]
JP-A-7-35916
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems and to provide a highly reliable optical element with a high yield when a color filter is manufactured at low cost by a simple process using an ink jet method. Specifically, when applying ink to the area surrounded by the partition walls, it is necessary to prevent color mixture between adjacent pixels, and to form pixels in the area without white spots and color unevenness. is there.
[0014]
[Means for Solving the Problems]
The invention according to claim 1 is a color filter substrate having a black matrix on at least a light-transmitting substrate, wherein the color filter substrate has a partition wall narrower than the black matrix on the black matrix. .
According to a second aspect of the present invention, the relationship between the line width x of the black matrix and the width y of the partition on the black matrix satisfies 0.2x ≦ y ≦ 0.8x. Color filter substrate.
The invention according to claim 3 is the color filter substrate according to any one of claims 1 to 2, wherein the partition walls have ink repellency.
According to a fourth aspect of the present invention, there is provided a color filter having a color portion formed by an ink jet method in an opening of a black matrix of a color filter substrate according to the first to third aspects.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of a color filter substrate and a color filter according to the present invention.
[0016]
As shown in FIG. 1, in the color filter substrate, a black matrix (a matrix-shaped light-shielding layer) is formed on a light-transmitting substrate, and a partition wall narrower than the width of the black matrix is formed on the black matrix. Red (R), green (G), and blue (B) patterned coloring layers are formed in openings between the black matrix and the partition walls. The planar shape of the black matrix is not particularly limited, such as a stripe type and a delta type.
[0017]
A glass substrate is generally used as the light-transmitting substrate (1 in FIG. 1) used in the present invention. The substrate is not limited to a glass substrate as long as it can withstand a post-process, and a plastic substrate such as PET, PES, or PEN can be used.
[0018]
Further, the partition (3 in FIG. 1) located above the black matrix (2 in FIG. 1) according to the present invention is characterized by being formed with a width smaller than the width of the black matrix. In the pixels formed in the portion surrounded by the partition walls by the ink jet method, the surface of the ink rises in a semi-cylindrical shape, and as a result, there is a problem of unevenness in the density. However, by forming the partition walls narrower than the width of the black matrix, when light is transmitted, the light that would have passed through the end of the ink surface (5 in FIG. 1) is blocked by the black matrix. Thus, a color filter is obtained in which light is transmitted only to a portion where ink is flat (4 in FIG. 1) and there is almost no variation in density. At this time, it is particularly desirable that the width y of the partition wall satisfies 0.2x ≦ y ≦ 0.8x with respect to the width x of the black matrix. If the value of y is other than this value, problems such as color mixing with adjacent pixels and color unevenness may occur.
[0019]
The material of the black matrix (2 in FIG. 1) in the present invention is a black resin composition mainly composed of a resin, a light shielding material, a dispersant, a solvent and the like. It is preferable to use carbon black as a light shielding material as a material constituting the black resin composition. By using carbon black, it is possible to obtain a black matrix having very good light-shielding properties.
[0020]
The black resin composition in the present invention can contain a photopolymerizable monomer, a photopolymerization initiator, and the like. This makes it possible to impart photosensitivity to the black resin composition and eliminates the need for a resist for patterning when forming a black matrix.
[0021]
Further, as a material of the black matrix (2 in FIG. 1) in the present invention, for example, a metal such as Cr, Mo, and Ta can be used.
[0022]
The material of the partition walls (3 in FIG. 1) in the present invention is preferably a photosensitive resin composition containing a photopolymerizable monomer, a photopolymerization initiator, and the like.
[0023]
Further, it is preferable to add a photosensitive silicon compound or the like to the partition wall material to enhance the ink repellency.
[0024]
Further, in order to completely prevent color mixing of ink, it is effective to increase not only the ink repellency of the partition walls themselves but also the thickness of the partition walls. Therefore, it is preferable that the thickness of the partition wall be 1 μm or more.
[0025]
The material of the colored ink in the present invention is a material containing a pigment, a resin and a solvent as main components. Dyes and pigments are used as the pigment. 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, acrylic resin is preferred.
[0026]
In order to improve the dispersion of the dye in the resin, a dispersant may be used, and as the dispersant, as a nonionic surfactant, for example, polyoxyethylene alkyl ether, etc., or as an ionic surfactant Examples thereof include sodium alkylbenzene sulfonate, polyfatty acid salts, fatty acid salt alkyl phosphates, tetraalkylammonium salts, and the like, as well as organic pigment derivatives, polyesters, and the like. One type of dispersant may be used alone, or two or more types may be used in combination. The solvent is required to have stability over time and dryness in addition to solubility, and is appropriately selected in relation to the dye and the resin.
[0027]
FIG. 2 shows a process for manufacturing a color filter substrate and a color filter according to the present invention.
[0028]
FIG. 2A shows a diagram in which a black matrix 2 serving as a light shielding portion is formed on a light transmitting substrate 1. First, a photosensitive resin to which an ink repellent is added is applied on the substrate 1 on which the black matrix 2 is formed, and prebaked to form a photosensitive resin layer 6 (FIG. 2B). Next, exposure is performed through a photomask 7 having a width smaller than the width of the black matrix 2 (FIG. 2C), and a developing process is performed to form a partition pattern showing ink repellency on the black matrix (FIG. 2). (D)). Next, using the ink jet head 8, R, G, and B colored portions 9 are formed (FIG. 2E), and ink drying is performed as necessary.
[0029]
【Example】
(Formation of black matrix)
A black resist containing carbon black (“V-259BK resist” manufactured by Nippon Steel Chemical Co., Ltd.) is coated on a glass substrate (product number 7059, manufactured by Corning Incorporated) using a spin coater to form a coating film of about 1.0 μm. Formed. By performing predetermined exposure, development, and baking treatment, a black matrix pattern having a square opening having a line width of 20 μm (= x) and 100 μm × 100 μm was prepared.
[0030]
(Formation of partition)
Next, on a glass substrate on which a black matrix pattern was formed, a photosensitive resin containing acrylic resin as a main component and a silicon-based additive added to give ink repellency to a coating film of about 1.0 μm by a spin coater. Formed. A substrate on which a narrower partition is formed on a black matrix by performing pattern exposure, development, and baking through a photomask having a line width of 10 μm (= y) narrower than the black matrix. Got.
[0031]
(Preparation of colored ink)
For the red ink, an acrylic resin (20 parts by weight of methacrylic acid, 15 parts by weight of hydroxyethyl methacrylate, 10 parts by weight of methyl methacrylate, 55 parts by weight of butyl methacrylate) is dissolved in 300 parts by weight of ethyl cellosolve, and the azobis 0.75 parts by weight of nitrile was added, and an acrylic resin obtained by reacting at 70 ° C. for 5 hours was diluted with ethyl cellosolve to a resin concentration of 20% by weight. 90.1 g of this diluted resin, 6.95 g of red pigment Chromophthal Red A2B (C, I, Pig Red 177 65300: manufactured by Ciba-Gaiky), and yellow pigment Paliotor Yellow L1820 (C, I, Pig Yellow 139: manufactured by BASF) 2.05 g and 0.9 g of a dispersant were added, and dispersed for 3 hours while cooling with a bead mill disperser. Ethyl cellosolve was used as a solvent, diluted to a viscosity of 5 cp or less, and stirred well to prepare a red ink.
[0032]
For the green ink, an acrylic resin (20 parts by weight of methacrylic acid, 15 parts by weight of hydroxyethyl methacrylate, 10 parts by weight of methyl methacrylate, and 55 parts by weight of butyl methacrylate) is dissolved in 300 parts by weight of ethyl cellosolve, and the azobis 0.75 parts by weight of nitrile was added, and an acrylic resin obtained by reacting at 70 ° C. for 5 hours was diluted with ethyl cellosolve to a resin concentration of 20% by weight. 90.1 g of this diluted resin, 7.55 g of green pigment Lionol Green 2YS (C, I, Pig Green 36: manufactured by Toyo Ink Mfg. Co., Ltd.), and yellow pigment Paliotor Yellow L1820 (C, I, Pig Yellow 139: BASF) 1.45 g and 0.9 g of a dispersant were added and dispersed for 3 hours while cooling with a bead mill disperser. The mixture was diluted with ethyl cellosolve as a solvent so that the viscosity became 5 cp or less, and stirred well to prepare a green ink.
[0033]
For blue ink, an acrylic resin (20 parts by weight of methacrylic acid, 15 parts by weight of hydroxyethyl methacrylate, 10 parts by weight of methyl methacrylate, 55 parts by weight of butyl methacrylate) is dissolved in 300 parts by weight of ethyl cellosolve, and azobis 0.75 parts by weight of nitrile was added, and an acrylic resin obtained by reacting at 70 ° C. for 5 hours was diluted with ethyl cellosolve to a resin concentration of 20% by weight. 91 g of this diluted resin, 0.8 g of blue pigment Heliogen Blue L6700F (manufactured by BASF), 0.1 g of violet pigment Rionogen Violet RL (manufactured by Toyo Ink Mfg.), And 0.9 g of dispersant were added, and a bead mill was added. The mixture was dispersed for 3 hours while cooling with a disperser. The mixture was diluted with ethyl cellosolve as a solvent so that the viscosity became 5 cp or less, and stirred well to prepare a blue ink.
[0034]
Next, using an ink jet recording apparatus equipped with a piezo-type head having a nozzle resolution of 180 dpi, R, G, and B pigment-dispersed inks prepared by the method described above were applied to the openings of the matrix-shaped partition walls on the glass substrate. . Next, a heat treatment was performed at 230 ° C. for 1 hour to cure the ink, thereby forming a color filter including R, G, and B colored portions.
[0035]
When the color filter thus produced was observed with an optical microscope, no color mixture was observed. In addition, each pixel was flat in the effective area, the color difference was good at 3 or less, and a highly reliable color filter could be manufactured.
[0036]
(Comparative example)
A black matrix resist was applied on a glass substrate in the same manner as in the example. Subsequently, a photosensitive resin to which an ink repellent additive was added was applied from above, exposed through a photomask, and then developed and baked to form a partition having the same width as the black matrix on the black matrix. A substrate was prepared. Next, the same ink as in Example 1 was applied to the opening to form a colored portion, thereby producing a color filter.
[0037]
When the color filter thus prepared was observed with an optical microscope, no color mixture was observed in each pixel. However, each pixel was not flat, a density variation was conspicuous, and a color difference was 10 or more.
[0038]
【The invention's effect】
As described above, according to the color filter substrate and the color filter according to the present invention, by providing a colored portion by a simple process using an ink jet method, there is no color mixing or color omission between pixels, and the effective pixel area Thus, a color filter free from density unevenness can be provided with good yield.
[0039]
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of one embodiment of the present invention.
FIG. 2 is an explanatory diagram of one embodiment of a color filter substrate and a method of manufacturing a color filter according to the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 light-transmitting substrate 2 black matrix 3 partition 4 colored portion 5 transmitting light 5 colored portion not transmitting light by black matrix 6 photosensitive resin layer 7 photomask 8 ink jet head 9 colored portion x width of black matrix y width of partition width

Claims (4)

What is claimed is: 1. A color filter substrate having a black matrix on at least a light-transmitting substrate, wherein the color filter substrate has a partition wall narrower than the black matrix on the black matrix. 2. The color filter substrate according to claim 1, wherein the relationship between the line width x of the black matrix and the width y of the partition on the black matrix satisfies 0.2x≤y≤0.8x. The color filter substrate according to claim 1, wherein the partition has ink repellency. 4. A color filter comprising a color portion formed by an ink jet method at an opening of a black matrix of the color filter substrate according to claim 1.

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