JP4445053B2 - Color filter and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color filter and a manufacturing method thereof, and more particularly, to a color filter for a liquid crystal display device excellent in display quality and a manufacturing method thereof.
[0002]
[Prior art]
In recent years, color liquid crystal display devices have attracted attention as flat displays. In general, a color liquid crystal display device includes a color filter including a black matrix and a colored layer composed of a plurality of colors (usually three primary colors of red (R), green (G), and blue (B)), and a thin film transistor (TFT element). And a TFT array substrate having a predetermined gap, and a liquid crystal material is injected into the gap. Therefore, this gap is the thickness of the liquid crystal layer itself. If the thickness of the liquid crystal layer is uneven, uneven brightness and color unevenness occur in the color liquid crystal display device, and the display quality is significantly impaired. It is desirable that the thickness of the is as uniform as possible.
[0003]
On the other hand, even if the liquid crystal layer is uniform, there is a fact that the transmittance of visible light varies depending on the color (R, G, B) of the pixel of the color filter. Therefore, in order to obtain a uniform and optimal visible light transmittance, it is necessary to optimize the thickness of the liquid crystal layer for each color (R, G, B).
[0004]
Therefore, a so-called multi-gap color filter has been developed in which the thickness of the colored layer is changed for each color of R, G, and B, and the liquid crystal layer is set to a predetermined thickness for each color.
[0005]
[Problems to be solved by the invention]
However, for example, when forming a colored layer having a different thickness for each color of R, G, and B as described above by a conventionally known pigment dispersion method, coloring of the photosensitive paint used in forming the smallest colored layer There was a problem that the material content was increased, and background stains, color unevenness, poor adhesion to the substrate, and the like occurred.
[0006]
Further, a colored layer having a uniform thickness is formed, a coating film is formed on the colored layer using a photosensitive resin composition for a protective layer, and the coating film is subjected to gradation exposure so that a transparent film having a desired thickness is obtained. There is a method of forming a protective layer to form a multi-gap color filter. However, when performing gradation exposure of a coating film by using a photomask for gradation exposure, there is a problem that it is difficult to produce a photomask, and when performing gradation exposure of a coating film by step exposure There is a problem that the time required for the exposure process becomes long.
[0007]
The present invention has been made in view of the above circumstances, and a color filter that enables a liquid crystal display device having an optimum liquid crystal layer thickness for each color of the colored layer and having excellent display quality, and the like. An object of the present invention is to provide a production method capable of easily producing a simple color filter.
[0008]
[Means for Solving the Problems]
  In order to achieve such an object, the color filter of the present invention includes a transparent substrate, a colored layer composed of three colors of red, green and blue formed on one surface of the transparent substrate, and at least the colored layer. A transparent protective layer formed thereon, and the size of the ultraviolet transmittance of the colored layer (average value of transmittance for ultraviolet rays in a wavelength range of 360 to 380 nm measured with an ultraviolet-visible spectrophotometer) is colored blue The largest in the layer, the smallest in the red colored layer, the transparent protective layerWas formed by forming a coating film of a photosensitive resin composition so as to cover the colored layer, irradiating ultraviolet rays from the back surface of the transparent substrate, exposing, developing and curing the coated film through the colored layer. The thickness of which depends on the amount of ultraviolet light exposure depending on the size of the ultraviolet transmittance of the colored layer,The more transparent protective layer on the colored layer, the larger the UV transmittance.Thickness isThe configuration is large.
[0009]
  Further, the color filter of the present invention includes a transparent substrate, a colored layer formed of one of the three colors red, green and blue formed on one surface of the transparent substrate, and a transparent protective layer formed on at least the colored layer. The size of the ultraviolet ray transmittance of the colored layer (the average value of the transmittance for ultraviolet rays in the wavelength range of 360 to 380 nm measured with an ultraviolet-visible spectrophotometer) is the smallest in the blue colored layer, and the red colored layer In the largest, the transparent protective layerWas formed by forming a coating film of a photosensitive resin composition so as to cover the colored layer, irradiating ultraviolet rays from the back surface of the transparent substrate, exposing, developing and curing the coated film through the colored layer. The thickness of which depends on the amount of ultraviolet light exposure depending on the size of the ultraviolet transmittance of the colored layer,The more transparent protective layer on the colored layer, the smaller the UV transmittance.Thickness isThe configuration is large.
[0010]
  Color filter of the present inventionManufacturing methodIsA colored layer composed of three colors of red, green, and blue on a transparent substrate, the size of the ultraviolet transmittance (average value of transmittance for ultraviolet rays in a wavelength range of 360 to 380 nm measured with an ultraviolet-visible spectrophotometer) A first step of forming the coating layer so as to cover the colored layer using the negative photosensitive resin composition for the transparent protective layer, the first step of forming the largest in the blue colored layer and the smallest in the red colored layer The thickness of the coating film is formed by exposing and developing the coating film through the colored layer by irradiating ultraviolet rays from the back surface of the transparent substrate, and by exposing the developed film to ultraviolet rays according to the ultraviolet transmittance of the colored layer. And a second step of forming a transparent protective layer by curing the coating film after the size of the colored layer having a larger ultraviolet transmittance is increased.The configuration is as follows.
[0011]
  The method for producing a color filter of the present invention is provided on a transparent substrate., Red, green and blueA colored layer consisting ofThe ultraviolet transmittance (average value of transmittance for ultraviolet rays in the wavelength range of 360 to 380 nm measured with an ultraviolet-visible spectrophotometer) is the smallest in the blue colored layer and the largest in the red colored layer.First step to form, for transparent protective layerPositive typeA coating film is formed so as to cover the colored layer using a photosensitive resin composition, and the coating film is exposed and developed through the colored layer by irradiating ultraviolet rays from the back surface of the transparent substrate, and ultraviolet rays of the colored layer are formed. Large transmittanceSoonDepending on the amount of ultraviolet light exposure,The thickness of the coating film is increased on the colored layer where the UV transmittance is small.Then, it was set as the structure which has the 2nd process of hardening the said coating film and forming a transparent protective layer.
[0012]
In the present invention, the coating film of the photosensitive resin composition for the transparent protective layer formed on the colored layer is exposed by irradiating ultraviolet rays from the back surface of the transparent substrate and passing through the colored layer. A difference occurs in the exposure amount of the coating film for each color according to the average value of the ultraviolet transmittance in the 360 to 380 nm region of the layer, and a transparent protective layer having a desired thickness for each color by development and curing It is formed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the drawings.
Color filter of the present invention
FIG. 1 is a longitudinal sectional view showing an example of a liquid crystal display device using a color filter according to an embodiment of the present invention. In FIG. 1, a liquid crystal display device 1 has a structure in which a color filter 11 of the present invention and a TFT array substrate 21 are opposed to each other through a liquid crystal layer 31.
[0014]
The color filter 11 of the present invention is formed on a transparent substrate 12, a black matrix (light shielding layer) 13 formed in a predetermined pattern on one surface of the transparent substrate 12, a colored layer 14 composed of a plurality of colors, and the colored layer 14. The transparent protective layer 16 and the transparent conductive film 17 are provided. The colored layer 14 is composed of a red colored layer 14R, a green colored layer 14G, and a blue colored layer 14B. Is different). That is, the magnitude of the ultraviolet transmittance of each color of the colored layer 14 is set to satisfy (1) 14R <14G <14B or (2) 14R> 14G> 14B.
[0015]
The transparent protective layer 16 provided on the colored layer 14 has a thickness corresponding to the magnitude of the ultraviolet transmittance of the colored layers 14R, 14G, and 14B of each color of the colored layer 14. In the illustrated example, the transparent protective layer 16 has the largest thickness of the transparent protective layer 16B on the blue colored layer 14B, and hereinafter, the transparent protective layer 16G on the green colored layer 14G and the transparent protective layer on the red colored layer 14R. The thickness becomes smaller in the order of 16R.
[0016]
On the other hand, the TFT array substrate 21 includes a display electrode 23 connected to a thin film transistor (not shown) on the substrate 22, and the colored layers 14 R, 14 G, and 14 B of the color filter 11 and the corresponding TFT array substrate 21. The display electrodes 23 are aligned so as to face each other.
[0017]
In such a liquid crystal display device 1, the thickness of the liquid crystal layer 31 is not uniform, and is an optimum thickness on each of the colored layers 14R, 14G, and 14B. In the illustrated example, the thickness of the liquid crystal layer 31 is TR, TG, TB corresponding to the thickness of the transparent protective layers 16R, 16G, 16B on the colored layers 14R, 14G, 14B, respectively. The thickness has been optimized. Therefore, the visible light transmittance in the colored layers 14R, 14G, and 14B of each color constituting the pixels of the color filter 11 is uniform and optimal, and the liquid crystal display device 1 having excellent display quality is possible.
[0018]
The transparent substrate 12 constituting the color filter 11 of the present invention has inflexible rigid materials such as quartz glass, pyrex glass and synthetic quartz plate, or has flexibility such as a transparent resin film and an optical resin plate. A flexible material can be used. Among them, Corning 7059 glass is a material having a small coefficient of thermal expansion, excellent dimensional stability and workability in high-temperature heat treatment, and is an alkali-free glass containing no alkali component in the active matrix. This is suitable for a color liquid crystal display device for LCDs based on this method.
[0019]
Further, the black matrix 13 formed on the transparent substrate 12 is formed by forming a metal thin film such as chromium having a thickness of about 1000 to 4000 mm by sputtering method, vacuum deposition method or the like, and patterning this thin film, carbon fine particles Forming a resin layer such as polyimide resin, acrylic resin, polyvinyl alcohol derivative resin, gelatin resin, etc. containing light shielding particles such as, and patterning this resin layer, light shielding properties such as carbon fine particles It may be any one formed by forming a photosensitive resin layer containing particles and patterning the photosensitive resin layer.
[0020]
In the colored layer 14 constituting the color filter 11 of the present invention, the red colored layer 14R, the green colored layer 14G, and the blue colored layer 14B are arranged in a desired pattern such as a mosaic type, a triangle type, a stripe type, or a four-pixel arrangement type. It is a thing. The thickness of the colored layer 14 can be set uniformly for each color in the range of about 0.5 to 3.0 μm. Further, considering the settings of the thicknesses TR, TG, and TB of the liquid crystal layer 31, a difference may be provided in advance in the thicknesses of the colored layers 14R, 14G, and 14B as shown in FIG. In this case, it is necessary to set the thickness of the colored layer within a range in which the content of the coloring material of the photosensitive resin composition to be used is high, and background stains, color unevenness, poor adhesion to the substrate, and the like do not occur.
[0021]
The transparent protective layer 16 constituting the color filter 11 of the present invention is formed using a known negative photosensitive resin or positive photosensitive resin. That is, as described later, when the ultraviolet ray transmittance of each color of the colored layer 14 is (1) 14R <14G <14B, it can be formed using a known negative type transparent photosensitive resin, Further, in the case where the ultraviolet ray transmittance of each color of the colored layer 14 is (2) 14R> 14G> 14B, it can be formed using a known positive type transparent photosensitive resin. The thickness of the transparent protective layer 16 on the colored layer 14 can be set in consideration of the liquid crystal material used, for example, the thickness of the transparent protective layer 16R on the red colored layer 14R is about 0 to 2.0 μm, The thickness of the transparent protective layer 16G on the green colored layer 14G is about 0.2 to 2.5 μm, the thickness of the transparent protective layer 16B on the blue colored layer 14B is about 1.5 to 4.0 μm, and the transparent protective layer 16R The difference in thickness of 16G can be set to about 0.2 to 1.0 μm, and the difference in thickness between the transparent protective layers 16G and 16B can be set to about 0.5 to 1.5 μm.
[0022]
The transparent conductive film 17 is formed of indium tin oxide (ITO), zinc oxide (ZnO), tin oxide (SnO), or an alloy thereof. The thickness of the transparent conductive film 17 is preferably about 200 to 2000 mm.
[0023]
Manufacturing method of color filter of the present invention
Next, the color filter manufacturing method of the present invention will be described using the above-described color filter 11 as an example.
[0024]
FIG. 3 is a process diagram showing an embodiment of a method for producing a color filter of the present invention. In the method for producing a color filter of the present invention, first, as a first step, a red colored layer 14R having a different ultraviolet transmittance for each color, green coloring, on a transparent substrate 12 having a black matrix 13 in a predetermined pattern shape. A colored layer 14 in which the layer 14G and the blue colored layer 14B are arranged is formed (FIG. 3A). The colored layer 14 can be formed, for example, by a pigment dispersion method using a photosensitive resin composition containing a coloring material in a known negative or positive photosensitive resist. The ultraviolet transmittance of each color can be set by adjusting the content of the ultraviolet absorber in the photosensitive resin composition of each color to be used. Examples of the ultraviolet absorber used include benzotriazole-based, benzophenone-based, benzoate-based, salicylic acid ester-based compounds, and cyanoacrylate-based compounds.
[0025]
The magnitude of the ultraviolet transmittance in the colored layer 14 is set so that (1) 14R <14G <14B or (2) 14R> 14G> 14B.
[0026]
In the present invention, since the optimization of the liquid crystal layer thickness is controlled by the thickness of the transparent protective layer, the thickness of the colored layer 14 can be uniformly formed in the range of about 0.5 to 3.0 μm. By providing a slight difference in the thicknesses of the layers 14R, 14G, and 14B, and further controlling the thickness of the transparent protective layer, it is possible to further expand the adaptive range of the liquid crystal layer thickness optimization.
[0027]
Next, as a second step, first, a coating film 15 is formed using a photosensitive resin composition for a transparent protective layer so as to cover the colored layer 14 (FIG. 3B). The photosensitive resin to be used is a negative photosensitive resin when the magnitude of the ultraviolet transmittance of the colored layers 14R, 14G, and 14B is (1) 14R <14G <14B, and the colored layers 14R, 14G, When the ultraviolet transmittance of 14B is (2) 14R> 14G> 14B, it is a positive photosensitive resin. Specifically, the negative photosensitive resin composition includes photopolymerizable and crosslinkable acrylic resins, polyimide resins, polyamide resins, epoxy resins, polyester resins, polyamic acid resins, and the like. One or more light transmissive negative photosensitive resins are used, and antioxidants, surfactants, antifoaming agents, fluorescent whitening agents, ultraviolet absorbers, dispersants, viscosity modifiers and the like are added thereto. The added one can be used. In addition, the positive photosensitive resin composition includes a novolac resin, a polyamic acid resin, a maleimide-styrene copolymer, a mixture of a polyvinylphenol derivative and a photoacid generator, a light transmission of a polyamic acid derivative, etc. 1 type or 2 types or more of a positive active photosensitive resin was added, and an antioxidant, a surfactant, an antifoaming agent, a fluorescent brightening agent, an ultraviolet absorber, a dispersant, a viscosity modifier, etc. were added thereto. Things can be used.
[0028]
The thickness of the coating film 15 is uniform, and the thickness of the coating film 15 can be set in consideration of the final shape of the transparent protective layer 16 having a desired thickness for each of the colored layers 14R, 14G, and 14B of each color. For example, it can set in the range of about 1.0-7.0 micrometers.
[0029]
Next, ultraviolet rays are irradiated from the back surface of the transparent substrate 12, and the coating film 15 is exposed through the colored layer 14 (FIG. 3C). Thereby, the coating film 15 is exposed with the exposure amount according to the magnitude | size of the ultraviolet-ray transmittance of colored layer 14R, 14G, 14B. That is, when the ultraviolet ray transmittance of the colored layers 14R, 14G, and 14B is {circle around (1)} 14R <14G <14B, the negative photosensitive coating film 15 has the maximum exposure on the blue colored layer 14B. The exposure amount is minimized on the red colored layer 14R. Further, when the ultraviolet ray transmittance of the colored layers 14R, 14G, 14B is (2) 14R> 14G> 14B, the exposure amount of the positive photosensitive coating film 15 is minimized on the blue colored layer 14B, The exposure amount is maximized on the red colored layer 14R. Therefore, the thickness of the transparent protective layer 16 formed by the development and curing treatment after exposure is the largest in the thickness of the transparent protective layer 16B on the blue colored layer 14B, and hereinafter, the transparent protective layer 16G on the green colored layer 14G. The thickness becomes smaller in the order of the transparent protective layer 16R on the red colored layer 14R (FIG. 3D). The thicknesses of the transparent protective layers 16R, 16G, and 16B on the colored layers 14R, 14G, and 14B of the respective colors are, for example, in the range of 0 to 1.5 μm for the transparent protective layer 16R and 0.5 to 2.0 μm for the transparent protective layer 16G. The transparent protective layer 16B can be set in the range of 1.0 to 2.5 μm.
[0030]
Then, using the indium tin oxide (ITO), zinc oxide (ZnO), tin oxide (SnO), etc., and their alloys on the transparent protective layer 16, well-known methods such as vapor deposition, sputtering, CVD, etc. The transparent conductive film 17 is formed in a predetermined pattern by the method (FIG. 3E). Thereby, the color filter 11 is obtained.
[0031]
【Example】
Next, an Example is shown and this invention is demonstrated further in detail.
[0032]
(Example 1) First, a chromium thin film (thickness 1000 mm) was formed on a glass substrate (Corning Corp. 7059 glass 0.7 mm thick) by a vacuum deposition method, and photosensitive by a spin coating method on this chromium thin film. A resist (OFPR800 manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied and dried. Next, the photosensitive resist layer was exposed and developed through a black matrix photomask to form a resist pattern. Using this resist pattern as a mask, the chromium thin film was etched, and the resist pattern was peeled and removed to form a black matrix. . The etching solution used was an aqueous solution in which ceric ammonium nitrate and perchloric acid were mixed.
[0033]
On the other hand, photosensitive resin compositions R1, G1, and B1 for colored layers having the following compositions were prepared using a base photosensitive resin having the following composition. These photosensitive resin compositions R1, G1, and B1 have an ultraviolet transmittance magnitude (average value of ultraviolet transmittance in a region of 360 to 380 nm) of R1 <by adjusting the addition amount of the ultraviolet absorber. G1 <B1 was set.
[0034]
Composition of base photosensitive resin
・ O-cresol novolac epoxy acrylate ... 9.5 parts by weight
(50% of hydroxyl groups reacted with phthalic anhydride)
・ Dipentaerythritol hexaacrylate: 9.5 parts by weight
(DPHA manufactured by Nippon Kayaku Co., Ltd.)
・ Irgacure 907 (Ciba Geigy) 1 part by weight
・ Irgacure 369 (Ciba Geigy)… 2 parts by weight
・ Ethyl cellosolve acetate: 80 parts by weight
・ Benzophenone: 1 part by weight
Red photosensitive resin composition R1
・ Base photosensitive resin: 50 parts by weight
・ Ethyl cellosolve acetate: 85 parts by weight
・ Chromophthaled BRN (Ciba Geigy)… 10 parts by weight
・ UV absorber: 5 parts by weight
2-Ethylhexyl-2cyano-3,3'-diphenyl acrylate
Green photosensitive resin composition G1
・ Base photosensitive resin: 50 parts by weight
・ Ethyl cellosolve acetate: 50 parts by weight
・ Giglime: 35 parts by weight
・ Lionol Green 2Y-301: 8 parts by weight
(Toyo Ink Manufacturing Co., Ltd.)
・ UV absorber: 2.5 parts by weight
2-Ethylhexyl-2cyano-3,3'-diphenyl acrylate
Blue photosensitive resin composition B1
・ Base photosensitive resin: 50 parts by weight
・ Ethyl cellosolve acetate: 50 parts by weight
・ Giglime: 35 parts by weight
・ Chromophthal blue A3R (Ciba Geigy)… 12 parts by weight
[0035]
Next, the photosensitive resin composition B1 is applied onto the glass substrate by a spin coating method (rotation speed: 600 rpm), dried, exposed through a photomask for a blue colored layer, developed, and colored blue. A layer (thickness 1.5 μm) was formed. Similarly, a green colored layer and a red colored layer were formed using the photosensitive resin composition G1 and the photosensitive resin composition R1 (corresponding to FIG. 3A). In addition, the photosensitive area | region of the initiator contained in the photosensitive resin composition of each said color is about 405 nm.
[0036]
The blue colored layer B, the green colored layer G, and the red colored layer R thus formed were measured with an ultraviolet-visible spectrophotometer for the average transmittance of ultraviolet light in the wavelength range of 360 to 380 nm. = 5.0 to 5.5%, green colored layer G = 2.5 to 3.0%, red colored layer R = 1.0% or less.
[0037]
Next, a negative photosensitive composition for a transparent protective layer having the following composition was prepared, applied on a glass substrate on which a colored layer had been formed by spin coating (rotation speed: 500 rpm), and dried at 100 ° C. for 5 minutes. Thus, a coating film was formed (corresponding to FIG. 3B).
[0038]
Photosensitive composition for protective layer
・ Dipentaerythritol hexaacrylate: 40 parts by weight
(DPHA manufactured by Nippon Kayaku Co., Ltd.)
・ Methyl methacrylate / methacrylic acid
/ Benzyl methacrylate copolymer: 40 parts by weight
・ Irgacure 907 (Ciba Geigy) ... 20 parts by weight
・ 2,2'-bis (2-chlorophenyl) -4,4 ', 5,5'
-Tetraphenylbisimidazole ... 10 parts by weight
・ Propylene glycol monomethyl ether acetate: 250 parts by weight
[0039]
Next, using a super high pressure mercury lamp from the back surface of the glass substrate, ultraviolet light of 365 nm is 300 mJ / cm.² Irradiated, and the coating film was exposed through the colored layer (corresponding to FIG. 3C). Thereafter, development is carried out by immersing in a developer prepared by adding a surfactant to a 0.1 wt% aqueous solution of sodium carbonate for 1 minute to remove the uncured portion of the coating film, and then heat treatment at 200 ° C. for 60 minutes To form a transparent protective layer (corresponding to FIG. 3D). The thickness of the transparent protective layer was 2.0 μm on the blue colored layer, 1.0 μm on the green colored layer, and 0.3 μm on the red colored layer. Next, a transparent conductive layer made of ITO (thickness 1000 mm) was formed on the transparent protective layer by a sputtering method to obtain a color filter (corresponding to FIG. 3E).
[0040]
This color filter was a good one without background stains, color unevenness, poor adhesion between the glass substrate and the colored layer, and the like.
[0041]
Further, using the above color filter, the liquid crystal layer has a thickness of 3.7 μm on the blue colored layer, 4.7 μm on the green colored layer, and 5.4 μm on the red colored layer, as shown in FIG. A display device was produced. The display quality of this liquid crystal display device was excellent.
[0042]
(Example 2) In the same manner as in Example 1, a black matrix was formed on a glass substrate (Corning Corporation 7059 glass thickness 0.7 mm).
In addition, using the same base photosensitive resin as in Example 1, photosensitive resin compositions R2, G2, and B2 for the colored layers having the following compositions were prepared. These photosensitive resin compositions R2, G2, and B2 have an ultraviolet transmittance magnitude (average value of ultraviolet transmittance in a region of 360 to 380 nm) of R2> by adjusting the addition amount of the ultraviolet absorber. G2> B2 was set.
[0043]
Red photosensitive resin composition R2
・ Base photosensitive resin: 50 parts by weight
・ Ethyl cellosolve acetate: 85 parts by weight
・ Chromophthaled BRN (Ciba Geigy)… 10 parts by weight
Green photosensitive resin composition G2
・ Base photosensitive resin: 50 parts by weight
・ Ethyl cellosolve acetate: 50 parts by weight
・ Giglime: 35 parts by weight
・ Lionol Green 2Y-301: 8 parts by weight
(Toyo Ink Manufacturing Co., Ltd.)
・ UV absorber: 2.5 parts by weight
2-Ethylhexyl-2cyano-3,3'-diphenyl acrylate
Blue photosensitive resin composition B2
・ Base photosensitive resin: 50 parts by weight
・ Ethyl cellosolve acetate: 50 parts by weight
・ Giglime: 35 parts by weight
・ Chromophthal blue A3R (Ciba Geigy) 15 parts by weight
・ UV absorber: 10 parts by weight
2-Ethylhexyl-2cyano-3,3'-diphenyl acrylate
[0044]
Next, the photosensitive resin composition B2 is applied onto the glass substrate by a spin coating method (rotation speed: 600 rpm), dried, exposed through a photomask for a blue colored layer, developed, and colored blue. A layer (thickness 1.5 μm) was formed. Similarly, a green colored layer and a red colored layer were formed using the photosensitive resin composition G2 and the photosensitive resin composition R2 (corresponding to FIG. 3A).
[0045]
About the blue colored layer B, the green colored layer G, and the red colored layer R thus formed, the average transmittance for ultraviolet rays in the wavelength range of 360 to 380 nm was measured in the same manner as in Example 1. As a result, the blue colored layer B = It was 0.5% or less, the green colored layer G = 10 to 11%, and the red colored layer R = 22 to 23%.
[0046]
Next, a positive photosensitive composition for a transparent protective layer having the following composition was prepared, applied on a glass substrate on which a colored layer had been formed by spin coating (rotation speed: 500 rpm), and dried at 120 ° C. for 4 minutes. Thus, a coating film was formed (corresponding to FIG. 3B).
[0047]
Photosensitive coating liquid for protective layer
・ Protected with t-butoxycarbonyl group (t-BOC)
Polyvinylphenol resin: 10 parts by weight
・ Hexamethoxymethylolated melamine: 10 parts by weight
・ Ethyl lactate: 50 parts by weight
Photoacid generator (TAZ-104 manufactured by Midori Chemical Co., Ltd.) 10 parts by weight
・ Propylene glycol monomethyl ether acetate: 150 parts by weight
[0048]
Next, ultraviolet rays of 365 nm are applied from the back surface of the glass substrate to 500 mJ / cm using an ultrahigh pressure mercury lamp.² Irradiated, and the coating film was exposed through the colored layer (corresponding to FIG. 3C). Thereafter, development is carried out by immersing in a developer prepared by adding a surfactant to 1.0% by weight of a potassium hydroxide aqueous solution for 1.5 minutes, and further, ultraviolet irradiation (300 mJ / cm2) is performed on the entire surface using a low-pressure mercury lamp.² After that, a transparent protective layer was formed by performing a heat treatment at 200 ° C. for 60 minutes (corresponding to FIG. 3D). The thickness of the transparent protective layer was 1.7 μm on the blue colored layer, 0.7 μm on the green colored layer, and 0.05 μm on the red colored layer. Next, an ITO transparent conductive film (thickness 1000 mm) was formed on the transparent protective layer by a sputtering method to obtain a color filter (corresponding to FIG. 3E).
[0049]
This color filter was a good one without background stains, color unevenness, poor adhesion between the glass substrate and the colored layer, and the like.
[0050]
Further, using the above color filter, the liquid crystal layer has a thickness of 3.7 μm on the blue colored layer, 4.7 μm on the green colored layer, and 5.4 μm on the red colored layer, as shown in FIG. A display device was produced. The display quality of this liquid crystal display device was excellent.
[0051]
(Comparative example)
First, using the same base photosensitive resin as in Example 1, photosensitive resin compositions R ′, G ′, and B ′ for colored layers having the following compositions were prepared.
[0052]
Red photosensitive resin composition R ′
・ Base photosensitive resin: 50 parts by weight
・ Ethyl cellosolve acetate: 85 parts by weight
・ Chromophthaled BRN (Ciba Geigy)… 10 parts by weight
Green photosensitive resin composition G ′
・ Base photosensitive resin: 75 parts by weight
・ Ethyl cellosolve acetate: 50 parts by weight
・ Giglime: 35 parts by weight
・ Lionol Green 2Y-301: 8 parts by weight
(Toyo Ink Manufacturing Co., Ltd.)
Blue photosensitive resin composition B ′
・ Base photosensitive resin: 100 parts by weight
・ Ethyl cellosolve acetate: 50 parts by weight
・ Giglime: 35 parts by weight
・ Chromophthal blue A3R (Ciba Geigy)… 12 parts by weight
[0053]
Next, the photosensitive resin composition B ′ is applied on a glass substrate (Corning Co., Ltd. 7059 glass, thickness 0.7 mm) by spin coating (rotation speed: 400 rpm) and dried to give a photo for blue coloring. It was exposed through a mask and developed to form a blue colored layer (thickness 3.2 μm). Similarly, a green colored layer (thickness: 2.2 μm) and a blue colored layer (thickness: 1.5 μm) are formed using the photosensitive resin composition G ′ and the photosensitive resin composition R ′, and the thickness is determined for each color. A colored layer having a different structure was formed.
[0054]
Next, a protective layer coating solution having the following composition is applied by a spin coating method (rotation speed: 700 rpm) and dried. Next, using an ultrahigh pressure mercury lamp through a photomask, a colored layer forming region and its 100mJ / cm of ultraviolet rays only at the periphery² Irradiated.
[0055]
Coating liquid for protective layer
・ Dipentaerythritol hexaacrylate: 40 parts by weight
(DPHA manufactured by Nippon Kayaku Co., Ltd.)
・ Methyl methacrylate / methacrylic acid
/ Benzyl methacrylate copolymer: 40 parts by weight
・ Irgacure 907 (Ciba Geigy) ... 20 parts by weight
・ 2,2'-bis (2-chlorophenyl) -4,4 ', 5,5'
-Tetraphenylbisimidazole ... 10 parts by weight
・ Propylene glycol monomethyl ether acetate: 400 parts by weight
[0056]
Thereafter, development was performed by immersing in a developer prepared by adding a surfactant to a 0.1% by weight aqueous solution of sodium carbonate for 1.5 minutes, followed by heat treatment at 200 ° C. for 60 minutes to form a transparent protective layer. . An ITO transparent conductive film (thickness 1000 mm) was formed on the transparent protective layer by sputtering to obtain a color filter for comparison.
[0057]
This color filter is not suitable for use as a color filter for a liquid crystal display device, particularly due to the thickening of the blue colored layer, resulting in color unevenness due to deterioration of the film thickness distribution and poor adhesion to the glass substrate. It was a thing.
[0058]
【The invention's effect】
As described above in detail, according to the present invention, the color filter comprises a colored layer having a plurality of colors having different ultraviolet transmittances for each color on one surface of the transparent substrate, and at least a transparent protection formed on the colored layer. And the thickness of the transparent protective layer differs depending on the color of the colored layer corresponding to the magnitude of the ultraviolet transmittance of the colored layer, and a liquid crystal display device manufactured using such a color filter Then, the optimal thickness of the liquid crystal layer can be set for each color of the colored layer, and a liquid crystal display device having excellent display quality is possible. In the color filter of the present invention, a colored layer composed of a plurality of colors having different ultraviolet transmittances for each color is formed on the transparent substrate in the first step, and a photosensitive resin composition for the transparent protective layer in the second step. A coating film is formed so as to cover the colored layer using an object, ultraviolet rays are irradiated from the back surface of the transparent substrate, the coating film is exposed and developed through the colored layer, and according to the magnitude of the ultraviolet transmittance of the colored layer The coating film is made to have a desired thickness for each color, and then the coating film is cured to form a transparent protective layer. In addition, a photomask for gradation exposure and a complicated exposure process are unnecessary, and a color filter can be easily manufactured.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an example of a liquid crystal display device using a color filter according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view showing another embodiment of the color filter of the present invention.
FIG. 3 is a process diagram showing an embodiment of a method for producing a color filter of the present invention.
[Explanation of symbols]
1. Liquid crystal display device
11. Color filter
12 ... Transparent substrate
13. Black matrix
14 (14R, 14G, 14B) ... colored layer
15 ... Coating film for transparent protective layer
16 ... Transparent protective layer
17 ... Transparent conductive film
31 ... Liquid crystal layer

Claims (4)

A transparent substrate, a colored layer composed of three colors of red, green and blue formed on one surface of the transparent substrate, and at least a transparent protective layer formed on the colored layer,
The magnitude of the ultraviolet transmittance of the colored layer (the average value of the transmittance with respect to ultraviolet rays in a wavelength range of 360 to 380 nm measured with an ultraviolet-visible spectrophotometer) is the largest in the blue colored layer and the smallest in the red colored layer,
The transparent protective layer forms a coating film of a photosensitive resin composition so as to cover the colored layer, and the coating film is exposed, developed, and cured through the colored layer by irradiating ultraviolet rays from the back surface of the transparent substrate. be those formed Te, the thickness and the thickness thereof depending on the exposure of ultraviolet light depends on the size of the ultraviolet transmittance of the colored layer, the more transparent protective layer is large colored layer size of UV transmittance Color filter characterized by being large. A transparent substrate, a colored layer composed of three colors of red, green and blue formed on one surface of the transparent substrate, and at least a transparent protective layer formed on the colored layer,
The magnitude of the ultraviolet transmittance of the colored layer (the average value of the transmittance for ultraviolet rays in the wavelength range of 360 to 380 nm measured with an ultraviolet-visible spectrophotometer) is the smallest in the blue colored layer and the largest in the red colored layer,
The transparent protective layer forms a coating film of a photosensitive resin composition so as to cover the colored layer, and the coating film is exposed, developed, and cured through the colored layer by irradiating ultraviolet rays from the back surface of the transparent substrate. be those formed Te, the thickness and the thickness thereof depending on the exposure of ultraviolet light depends on the size of the ultraviolet transmittance of the colored layer, the more transparent protective layer on the colored layer small size of the UV transmittance Color filter characterized by being large. A colored layer composed of three colors of red, green, and blue on a transparent substrate, the size of the ultraviolet transmittance (average value of transmittance for ultraviolet rays in a wavelength range of 360 to 380 nm measured with an ultraviolet-visible spectrophotometer) A first step of forming the largest in the blue colored layer and the smallest in the red colored layer,
A coating film is formed so as to cover the colored layer using a negative photosensitive resin composition for a transparent protective layer, and the coating film is exposed through the colored layer by irradiating ultraviolet rays from the back surface of the transparent substrate. Develop and cure the coating film after increasing the thickness of the coating film on the colored layer having a large ultraviolet transmittance by the exposure amount of the ultraviolet light according to the ultraviolet transmittance of the colored layer. And a second step of forming a transparent protective layer. A method for producing a color filter, comprising: A colored layer composed of three colors of red, green, and blue on a transparent substrate, the size of the ultraviolet transmittance (average value of transmittance for ultraviolet rays in a wavelength range of 360 to 380 nm measured with an ultraviolet-visible spectrophotometer) A first step of forming the smallest in the blue colored layer and the largest in the red colored layer,
Forming a coating film so as to cover the colored layer using a positive photosensitive resin composition for a transparent protective layer, exposing the coating film through the colored layer by irradiating ultraviolet rays from the back surface of the transparent substrate, Develop and cure the coating film after increasing the thickness of the coating film on the colored layer having a smaller ultraviolet transmittance by the amount of ultraviolet light exposure corresponding to the ultraviolet transmittance of the colored layer. And a second step of forming a transparent protective layer. A method for producing a color filter, comprising:

Images