JPH10260525A - Black photosensitive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a black matrix which is free from display unevenness, has good optical characteristics and excellent display grade and embodies flat color filters free from light leakage at a low cost by forming this black matrix of two kinds of photoacid generating agents having specific absorption wavelengths. SOLUTION: This compsn. contains 20 to 45 wt.% resin material, 5 to 20 wt.% crosslinking agent, 2 to 15 wt.% photoacid generating agents and 20 to 60 wt.% black pigments. The photoacid generating agent consist of the photoacid generating agent having the absorption wavelength at <=340 nm and the photoacid generating agent having the absorption wavelength at 5340 to 380 nm. The photoacid generating agent which do not have the absorption wavelength at about >=400 nm are preferable as such photoacid generating agents. The photoacid generating agents having the absorption wavelength at <=340 nm contribute mainly to the improvement in sensitivity. The photoacid generating agents having the absorption wavelength at $340 to 380 nm are sensitized by light of a wavelength region which is not completely shielded by pixels and, therefore, these agents are sensitized on the slopes of the pixels as well and acids may be generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a material for manufacturing a color filter used for a liquid crystal display or the like.
In particular, the present invention relates to a black photosensitive resin composition used for forming a black matrix.

[0002]

2. Description of the Related Art Hitherto, color filters have been widely used in many fields such as liquid crystal display devices. Normally, a color filter is formed by arranging pixels of a plurality of colors such as red, green, and blue on a transparent substrate. In a color filter, a black matrix is formed between pixels in order to obtain a good contrast image. This black matrix is TF
It also has an effect of preventing a malfunction of a transistor used for a T drive type liquid crystal display.

[0003] Usually, a black matrix is formed of a metal thin film having a fine pattern on a glass substrate. For example, first, a thin film made of a metal or a metal compound such as chromium, nickel, or aluminum is formed by a vacuum film forming method such as an evaporation method or a sputtering method. After that, a photolithography method, for example, applying a photoresist on the thin film,
In general, a method of forming a resist pattern by drying, irradiating ultraviolet rays through a photomask, and developing to form a fine pattern black matrix through an etching step and a resist peeling step. However, the manufacturing cost of the black matrix manufactured in the above process is very high due to the complexity of the process, and as a result, the cost of the color filter using the black matrix is also high.

Further, a metal generally used as a metal thin film has a high reflectance on its surface. Therefore, when a color filter using the metal thin film is mounted on a transmission type liquid crystal display, strong external light is required. When light is incident on a color filter, for example, in the case of a chromium thin film, there is a problem that display quality is remarkably deteriorated due to strong reflected light. Therefore, in order to improve the problem of the black matrix using such a metal thin film, various methods are being studied.For example, a black pigment and an organic pigment are dispersed in the photosensitive resin composition as needed, A method of forming a black matrix by using this has been proposed. The method using this black photosensitive resin composition has the advantages that the manufacturing process can be simplified, the cost can be reduced, and the display quality does not deteriorate due to reflection.

[0005]

However, in order to obtain a sufficient light-shielding property using only the black pigment, a film thickness of about 1 μm or more is required. As a result, a so-called one-sided projection is formed at a portion overlapping with a plurality of color pixels, which is a margin for positioning, which causes display unevenness.

Japanese Patent Application Laid-Open No. 6-59119 discloses a method in which a black photosensitive resin layer is provided on the gaps between pixels of a plurality of colors arranged at predetermined positions and on the upper portion thereof, and then the plurality of color pixels are used as a mask on the back side of the substrate. A method of selectively providing a black matrix only in a gap between a plurality of color pixels by exposing the entire surface to a material from the same and a material therefor have been proposed. This so-called,
When the back exposure method is used, there is an advantage that no ridge-like projection is generated. However, in order to ensure a sufficient thickness of the black black matrix and to prevent the black layer from remaining on the multi-color pixels, the light-shielding property of the multi-color pixels in the photosensitive wavelength region of the black photosensitive resin composition is required. Must be high enough. Therefore, an additive such as an ultraviolet absorber such as titanium oxide, zinc oxide, a benzotriazole-based compound, or a coumarin-based compound, or an optical brightener must be added to the multi-color pixels serving as a mask. However, the addition of these ultraviolet absorbers and the like to the multi-color pixels has a problem that the optical properties of the color filter, that is, the transparency and the contrast ratio are significantly impaired. Further, in the case of the photopolymerizable photosensitive resin, the photosensitive characteristic curve is comparatively gentle and the γ value is small. Therefore, in order to obtain a sufficient film thickness, a sufficiently large exposure dose (150 to 200 mJ / cm ² ) is required.
Is required. However, in order to perform a sufficient exposure process, a higher light-shielding property is required for a plurality of color pixels.

[0007] Further, the black pigment has a property of capturing radicals generated by a photopolymerization initiator used in a photopolymerizable photosensitive resin at the time of ultraviolet irradiation. Therefore, the black pigment inhibits photopolymerization and makes it difficult to form a sufficient pixel at an economical exposure amount, and has a problem that the pattern is peeled off during development. Also, the shape at the end of each multi-color pixel may be not vertical but inclined, but in such a case, as shown in FIG. 3, the multi-color pixels 12, 12,. When a black matrix is formed using a back exposure method as a mask, the black resin layer 16
Are located on the inclined surfaces 14, 14,... At the end of each pixel 12, and are shielded from light by the pixels 12 forming the inclined surfaces 14, 14,. Not done.
As a result, when developed, as shown in FIG.
.. Cannot be formed on the inclined surfaces 14, 14,...
In particular, the blue pixels of the transmission type color filter have high light absorption near 365 nm which is the photosensitive wavelength region of the black photosensitive resin composition, and therefore, the inclined surfaces 14, 1 at the pixel end portions 12, 12,.
It is even more difficult to form a black matrix on 4,.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is a color which is low in cost, has no display unevenness, has good optical characteristics, is excellent in display quality, is flat, and has no light leakage. It is an object of the present invention to provide a black photosensitive resin composition capable of forming a black matrix for realizing a filter.

[0009]

The black photosensitive resin composition of the present invention comprises 20 to 45% by weight of a resinous material and 5 to 2% of a crosslinking agent.
0% by weight, 2 to 15% by weight of photoacid generator, 20 to black pigment
60% by weight, and the photoacid generator has an absorption wavelength of 34.
0 nm or less photoacid generator and absorption wavelength of 340-380
and a photo-acid generator at nm. Further, as such a photoacid generator, those having an absorption wavelength of not less than about 400 nm as much as possible are preferable.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The black photosensitive resin composition of the present invention to be a black matrix contains at least a resin material, a crosslinking agent, a photoacid generator, and a black pigment.

As the resin-based material, a polymer compound containing an OH group which can be a crosslinking point and soluble in an aqueous alkaline solution is applied. Examples of such a resin-based material include phenols such as phenol novolak and p-hydroxystyrene, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, acrylic acid, methacrylic acid, maleic acid, and fumaric acid. Etc. O
Examples include a homopolymer or copolymer of a monomer containing an H group. Other monomers that can be used for copolymerization include styrene, phenylmaleimide, methyl acrylate, ethyl acrylate, butyl acrylate, benzyl acrylate, methyl methacrylate, ethyl methacrylate,
Examples thereof include butyl methacrylate and benzyl methacrylate. These resin materials are used in the range of 20 to 45% by weight, preferably 25 to 35% by weight. If the amount is too small, problems such as deterioration of the photosensitive function, deterioration of the pattern shape due to aggregation of carbon, and insufficient film strength and adhesion may occur.

Examples of the crosslinking agent include methylolated urea, urea resin, methylolated melamine, butyrolated melamine,
It is possible to use methylolated guanamine or an alkyl ether of these compounds. Alkyl ethers are more preferred because of their excellent thermal stability.
The alkyl group of the alkyl ether has 1 to 1 carbon atoms.
5 alkyl groups are preferred. In particular, as this alkyl ether compound, an alkyl ether compound of hexamethylolmelamine, which is excellent in sensitivity, is more preferable. Further, a compound having two or more epoxy groups can also be used. These crosslinking agents are used in the range of 5 to 20% by weight. If the amount is too small, the photosensitive characteristics are hindered. If the amount is too large, the light-shielding property is insufficient.

In the present invention, a photoacid generator having an absorption wavelength of 340 nm or less and 340 to 38 are used as the photoacid generator.
Used in combination with a photoacid generator at 0 nm. As a photoacid generator having an absorption wavelength of 340 nm or less, an absorption wavelength of 2
More preferably, it is 90 to 340 nm. As the photoacid generator, a trihalomethyl group-containing triazine derivative or an onium salt that has an absorption in a wavelength range included in light emission of a light source and generates an acid by light absorption is preferable.

As such photoacid generators having an absorption wavelength of 340 nm or less, for example, trihalomethyl group-containing triazine derivatives include 2,4,6-tris (trichloromethyl) -s-triazine and 2-phenyl- 4,6-bis (trichloromethyl) -s-triazine, 2- (p-
Methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-chlorophenyl)-
4,6 bis (trichloromethyl) -s-triazine and the like can be mentioned. Also, as onium salts,
Diphenyliodonium tetrafluoroborate, diphenyliodonium hexafluorophosphonate, diphenyliodonium hexafluoroarsenate, diphenyliodonium trifluoromethanesulfonate,
Diphenyliodonium trifluoroacetate, diphenyliodonium-p-toluenesulfonate,
Methoxyphenylphenyliodonium tetrafluoroborate, 4-methoxyphenylphenyliodonium hexafluorophosphonate, 4-methoxyphenylphenyliodonium hexafluoroarsenate,
Methoxyphenylphenyliodonium trifluoromethanesulfonate, 4-methoxyphenylphenyliodonium trifluoroacetate, 4-methoxyphenyliodonium-p-toluenesulfonate, bis (4
-Tert-butylphenyl) iodonium tetrafluoroborate, bis (4-tert-butylphenyl) iodonium hexafluorophosphonate, bis (4-tert-butylphenyl) iodonium hexafluoroarsenate, bis (4-tert-butylphenyl) iodonium Diaryliodonium salts such as trifluoromethanesulfonate, bis (4-tert-butylphenyl) iodonium trifluoroacetate, bis (4-tert-butylphenyl) iodonium-p-toluenesulfonate, triphenylsulfonium tetrafluoroborate, triphenyl Sulfonium hexafluorophosphonate, triphenylsulfonium hexafluoroarsenate,
Triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium trifluoroacetate, triphenylsulfonium-p-toluenesulfonate, 4-methoxyphenyldiphenylsulfonium tetrafluoroborate, 4-methoxyphenyldiphenylsulfonium hexafluorophosphonate, 4-methoxyphenyldiphenyl Sulfonium hexafluoroarsenate, 4-methoxyphenyldiphenylsulfonium trifluoromethanesulfonate, 4-methoxyphenyldiphenylsulfonium trifluoroacetate, 4-methoxyphenyldiphenylsulfonium-p
-Trienesulfonate, 4-phenylthiophenyldiphenyltetrafluoroborate, 4-phenylthiophenyldiphenylhexafluorophosphonate, 4-phenylthiophenyldiphenylhexafluoroarsenate, 4-phenylthiophenyldiphenyltrifluoromethanesulfonate, 4-phenyl Trial sulfonium salts such as thiophenyldiphenyltrifluoroacetate and 4-phenylthiophenyldiphenyl-p-toluenesulfonate are exemplified.

Further, as a photoacid generator having an absorption wavelength of 340 to 380 nm, for example, a trihalomethyl group-containing triazine derivative is 2- (p-methoxystyryl)
-4,6-bis (trichloromethyl) -s-triazine, 2-piperonyl-4,6-bis (trichloromethyl) -s-triazine, 2- (4'-methoxy-1'-
Naphthyl) -4,6-bis (trichloromethyl) -s-
Triazine, 2- (p-methylthiophenyl) -4,6
-Bis (trichloromethyl) -s-triazine and the like. Also, as onium salts,
And trial sulfonium salts such as hydroxynaphthyl sulfonium trifluoromethane sulfonate.

Above all, 4-phenylthiophenyldiphenylhexafluorophosphonate having an absorption wavelength range of 340 nm or less, or 2- (p-methoxyphenyl)-
Any of 4,6-bis (trichloromethyl) -s-triazine, 2-piperonyl-4,6-bis (trichloromethyl) -s-triazine having an absorption wavelength of 340 to 380 nm, or 2- (p-methylthio) Phenyl)-
It is preferable to use in combination with any of 4,6-bis (trichloromethyl) -s-triazine. Also, since the blue pixel hardly absorbs and transmits light having a wavelength of about 400 nm or more, if the photoacid generator has an absorption wavelength of 400 nm or more, the black photosensitive resin composition on the pixel is exposed and remains. Therefore, it is preferable that the photoacid generator obtained by combining the above two types of photoacid generators does not have an absorption wavelength region in a region of 400 nm or more. In such a case, a visible light cut filter is not required.

A photoacid generator having an absorption wavelength range of 340 nm or less mainly contributes to improvement of sensitivity. 34 absorption wavelength
Since the photoacid generator at 0 to 380 nm is sensitive to light in a wavelength range that is not completely blocked by the pixel, it can also be exposed on the inclined surface of the pixel and generate acid on the inclined surface. it can. However, this absorption wavelength is 340
Among photoacid generators having a wavelength of 380 nm to 380 nm, a photoacid generator having a high sensitivity has a sensitivity of 400 nm or more, so that the above-described problem is likely to occur, and a photosensitizer having a high sensitivity is not so desirable. Therefore, the present invention comprises at least two types of specific photoacid generators in order to have both the function of increasing the sensitivity and the ability to form a black matrix on the inclined surface of the pixel.

In the combination ratio of the photoacid generator, the photoacid generator having an absorption wavelength range of 340 nm or less is compared with a photoacid generator having a wavelength of 340 nm or less.
50-150% by weight of a photoacid generator at 0-380 nm,
More preferably, it is used in the range of 75 to 125% by weight. If the photoacid generator of 340 to 380 nm is too small, a black matrix cannot be formed on the inclined shape of the end portion of the multi-color pixel, and if it is too large, the sensitivity becomes low,
This is because the required exposure amount increases, and the black photosensitive resin remains on the multi-color pixels. The photoacid generator obtained by combining these is used in the range of 2 to 15% by weight based on the whole. If it is added in excess of 15% by weight, the amount of acid generated is too large and the acid diffuses into unexposed areas due to heating after pattern exposure, causing a cross-linking reaction and causing a reduction in resolution. On the other hand, when the amount is less than 2% by weight, the amount of generated acid is insufficient, the crosslinking reaction does not proceed sufficiently, and a pattern cannot be formed.

As the black pigment, a mixture of carbon black, titanium oxide, iron black, aniline black and an organic pigment can be used. If necessary, an acrylic resin, a dispersion medium for improving the dispersibility of the pigment, It is also possible to add an epoxy resin or the like. Further, a polymer dispersant, a derivative of an organic dye, or the like may be added as a dispersant. Further, a polymer-grafted carbon black grafted with a polymer compound may be used. These black pigments are used in the range of 20 to 60% by weight, preferably 40 to 50% by weight. If the amount is too small, sufficient light-shielding properties cannot be obtained, and if the amount is too large, the function as a photosensitive resin cannot be maintained.

The black photosensitive resin composition of the present invention can be easily obtained by kneading these materials using a dispersing machine such as a two-roll mill, a three-roll mill, a sand mill, a paint conditioner and the like. As a diluting solvent to further improve the workability at the time of dispersion, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, butyl cellosolve acetate, ethyl carbitol, ethyl carbitol acetate, diethylene glycol, cyclohexanone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, Organic solvents such as lactic acid esters may be used.

Hereinafter, an example of the steps of the method for manufacturing a color filter of the present invention will be described with reference to the drawings. First, as shown in FIG. 3, blue, red or green multi-color pixels 12, 12,... Are provided at predetermined positions on a substrate 10, and above and above the multi-color pixels 12, 12,. Each multi-color pixel 12, 1
The black photosensitive resin composition of the present invention is uniformly applied to the gaps of 2,... Using a spinner method, a bar coating method, a roll coating method, a curtain coating method, or the like to form a black resin layer 16. As the method of forming the multi-color pixels, any of the currently practiced methods such as a dyeing method, a pigment dispersion method, a printing method, and an electrodeposition method, which are conventional techniques, may be used. When the substrate is brought into close contact, 70 ° C to 100 ° C
Heat of about ° C may be applied.

Next, ultraviolet light is irradiated from the back surface of the transparent substrate 10 to perform exposure, and the gap portions 18 and 1 of the multi-color pixels 12 are exposed.
An acid is generated only in portions of the black resin layer 16 located at 8,. As a light source used for exposure, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, or the like is used. When the photosensitive wavelength range of the black photosensitive resin composition is 400 nm or more, the multi-color pixel 1
The light passing through 2 is absorbed by the black resin layer 16 and the black resin layer 16 is formed as a residue on the multi-color pixels 12. Therefore, it is preferable that the light is exposed through a visible light cut filter. Next, a heating temperature of 90 ° C. to 150 ° C. for 15 hours
In seconds to 5 minutes, utilizing the catalytic reaction of acid, the black resin layer 16
The cross-linking reaction is caused only in the gap portion 18 of the multi-color pixel 12. Next, using the developing solution, the multi-color pixels 12,
12,..., The black resin in the uncrosslinked portion is removed to obtain a color filter as shown in FIG. The black resin layer 16
If is larger than the multi-color pixel 12, grinding may be performed. Developers include inorganic alkali solutions such as sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate, alkylamines such as triethylamine, alcoholamines such as triethanolamine, and quaternary such as tetramethylammonium hydroxide. Ammonium salts and the like can be used.

In the present invention, by using a specific photoacid generator, an effect of efficiently absorbing light having a wavelength of 300 to 400 nm and generating an acid with high sensitivity is exhibited. In addition, it is possible to form a black matrix by crosslinking and curing also on the inclined surface formed at the end of each of the multi-color pixels, and the surface of the multi-color pixel and the surface of the black matrix become flat. Also, even when using the exposure method from the back side of the transparent substrate, it is not necessary to cure the inside of the black resin layer with a large amount of ultraviolet rays as in the conventional case, absorption of the ultraviolet region of the multi-color pixels, optical density of the black resin layer. Irrespective of this, it is possible to form a color filter having no light-shielding film overlapping on a plurality of color pixels by exposure with a small amount of ultraviolet light from the back side of the transparent substrate.

[0024]

As shown in FIG. 3, on a transparent glass substrate (Corning Co., Ltd .: "7059") 10, red,
A colored pattern of green, blue pixels 14, 14,... Was formed. Each color pixel has a color mosaic CRY
7000 "," Color Mosaic CGY7000 "and" Color Mosaic CBV7000 "manufactured by Fuji Hunt. The film thickness of these multi-color pixels was 1.5 μm.
The black photosensitive resin composition was prepared by putting each component shown in Table 1 and 100 g of glass beads in a glass bottle and dispersing them for 2 hours using a paint shaker.

[0025]

[Table 1]

As shown in FIG. 1, "TAZ-104" has an absorption peak at 331 nm, and "TAZ-107" has a photo-acid generator of 35%.
It has an absorption peak at 7 nm.

A plurality of color pixels 14, 14,... Of a red, green, and blue coloring pattern formed with the black photosensitive resin dispersion liquid.
・ Apply at 760 rpm for 5 seconds with a spinner,
After drying, a black resin layer 16 as shown in FIG. 3 was formed.
3kW ultra-high pressure mercury lamp (emission wavelength range: 300-450nm)
The whole surface was exposed from below the transparent substrate 10 at an exposure amount of 60 mJ / cm ^{2 using} the multicolor pixels as a mask.
Thereafter, heating was performed at 90 ° C. for 1 minute using a hot plate. Using a 1.25% aqueous solution of sodium hydroxide, developing is performed for 30 seconds using a method of spraying a shower while rotating the substrate, and the unexposed portions on the red, green, and blue colored patterns that are a plurality of color pixels are developed. The black resin layer was removed. Finally, it was heated at 230 ° C. for 1 hour in a clean oven to obtain a color filter. The obtained color filter is shown in FIG.
As shown in FIG.
14, a black resin layer 16 was also formed on the substrate, and the substrate was excellent in flatness. Further, there was no light leakage, and the contrast was good.

[Comparative Example] The above-mentioned “TAZ” was used as a photoacid generator.
A black matrix was prepared in the same manner as in the example except that only -104 "was used. As a result, a black matrix could not be formed on the inclined surface of the multi-color pixel, particularly at the end of the blue pixel. For this reason,
Light leaked from pixels other than the multi-color pixels, and good contrast could not be obtained. Further, since a black matrix cannot be formed on the inclined shape at the end of the multi-color pixel, a color filter having good flatness cannot be obtained.

[0029]

Since the black photosensitive resin composition of the present invention is a highly sensitive resist itself and has a high γ value, it can be sufficiently crosslinked and cured with a small exposure. Therefore, even when a color filter is prepared using the back exposure method, the amount of exposure is reduced, and even if an additive such as an ultraviolet absorber is not added to the multi-color pixels of each color used as a mask, the multi-color pixels can be formed. An appropriate development process can be performed without causing fog. Therefore, a color filter having excellent optical characteristics such as transparency and contrast ratio can be obtained. Also, since the black photosensitive resin composition located on the inclined surface formed on the pixel can be sufficiently cross-linked and cured, the gap between each of the plurality of color pixels can be completely filled with the black matrix, and the flatness can be achieved. Thus, a color filter without light leakage can be obtained. In addition, since the back exposure method can be used without any inconvenience in this way, it is possible to prevent the generation of a ridge-like projection due to the overlap of each of the plurality of color pixels and the black matrix, and this is useful in a liquid crystal display using a color filter. Display unevenness can be prevented. Therefore, it is possible to obtain a color filter having a thick black matrix formed of a black resin having a low reflectance.

[Brief description of the drawings]

FIG. 1 is a graph showing the absorption wavelength of a photoacid generator used in Examples.

FIG. 2 is a side sectional view showing an example of a color filter.

FIG. 3 is a side sectional view showing a process of manufacturing a color filter.

FIG. 4 is a side sectional view showing a conventional color filter.

[Description of Signs] 10 Substrate 12 Multi-color pixels 16 Black resin layer

Claims (2)

[Claims] 1. A resinous material of 20 to 45% by weight, a crosslinking agent 5
-20% by weight, photoacid generator 2-15% by weight, black pigment 2
0 to 60% by weight, and the photoacid generator has an absorption wavelength of 340 nm or less and a photoacid generator having an absorption wavelength of 340 nm or less.
A black photosensitive resin composition comprising a photoacid generator having a wavelength of from 380 nm to 380 nm. 2. The photo-acid generator having an absorption wavelength of 40
2. The black photosensitive resin composition according to claim 1, wherein the thickness is not more than 0 nm.