Radiation imagery chemistry: process – composition – or product th – Radiation modifying product or process of making – Screen other than for cathode-ray tube
Reexamination Certificate
1999-07-23
2001-01-09
McPherson, John A. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Radiation modifying product or process of making
Screen other than for cathode-ray tube
C430S270100, C430S321000
Reexamination Certificate
active
06171733
ABSTRACT:
FTELD OF THE INVENTTON
The present invention relates to a material for forming a black matrix for a color liquid crystal display and a method for forming a black matrix for a color liquid crystal display using the same.
BACKGROUND OF THE TNVENTTON
The color filter for a color liquid crystal display influences the displaying grade of the color liquid crystal display. Above all, it is essential that a black matrix for a color filter not only have sufficient light-shielding ability but also be formed with high resolution for achieving a high opening factor and high contrast.
Chromium-deposited films have so far been used in black matrices for a color filter. However, although black matrices comprising a chromium-deposited film are excellent in light-shielding ability, they have several problems that ghost image is caused as they have a high reflection coefficient leading to the deterioration of visibility, the color filter manufacturing process in which chromium is used in a black matrix is complicated and expensive, and the disposal of chromium waste solutions is problematic.
As has been the circumstances, black matrices comprising a photosensitive resin film having dispersed therein a black pigment and patterned upon a design have been developed. These black matrices have a low reflection coefficient and can be manufactured inexpensively. A radical polymerization type photosensitive resin is used as this photosensitive resin having dispersed therein a black pigment, but a radical polymerization type photosensitive resin is barely hardened in the range where a light reaches, therefore, hardening becomes insufficient in the vicinity of the interface between the film and the substrate. As a result, the development latitude becomes narrow.
Further, in conventional black pigments, even if a photosensitive resin composition is compounded by combining a black pigment with a quinonediazide compound, an alkali-insoluble substance is formed by merely blending, coating and drying the components, as a result, the image contrast is lowered or, in some cases, the composition comes to be substantially insoluble in a developing solution and patterning becomes impossible.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a black matrix-forming material for a color liquid crystal display in which a hardening reaction proceeds sufficiently to the interface with the substrate even with a high concentration of a black pigment and which can provide wide development latitude.
A further object of the present invention is to provide a black matrix-forming material for a color liquid crystal display in which a hardening reaction does not proceed by merely blending, coating and drying the components constituting the black matrix-forming material, the solubility contrast of the exposed area and the unexposed area to the developing solution is sufficiently large, and from which a highly accurate black matrix can be produced.
Another object of the present invention is to provide a method for forming a black matrix for a color liquid crystal display of high concentration and high accuracy.
The above objects of the present invention have been attained by a black matrix-forming material for a color liquid crystal display and a method for forming a black matrix for a color liquid crystal display using the same as described in the following items (1) and (2).
(1) A material for forming a black matrix for a color liquid crystal display comprising:
(A) an alkali-soluble resin obtained by the condensation reaction of phenols containing at least cresol with aldehydes;
(B) an acid-crosslinkable methylolated melamine compound;
(C) a compound which absorbs a light and then generates an acid;
(D) a dispersant represented by formula (I):
wherein R
1
represents a straight chain or branched alkyl group having from 1 to 24 carbon atoms, and this alkyl group may have a substituent; R
2
and R
3
each represents a hydrogen atom or a methyl group; R
4
represents a hydrogen atom, a straight chain or branched alkyl group having from 1 to 24 carbon atoms, —COR
5
or —CONR
6
, and this alkyl group may have a substituent; R
5
and R
6
each represents an alkyl group having from 1 to 12 carbon atoms, an aryl group having from 6 to 12 carbon atoms, or an alkenyl group having from 6 to 32 carbon atoms; m represents 0, 1 or 2; n represents 1, 2 or 3, provided that m+n is 3; and a and b each represents a number of from 0 to 200, provided that a+b is from 2 to 200; and
(E) a black pigment.
(2) A method for forming a black matrix for a color liquid crystal display which comprises coating the above black matrix-forming material for a color liquid crystal display on a transparent substrate, subjecting the film formed to exposure of the prescribed patterning, heat treating the film to effect crosslinking of the exposed area and distributing the acid generated by the exposure to the substrate, and then removing the unexposed area by alkali development.
DETAILED DESCRIPTION OF THE INVENTION
When the above-described black matrix-forming material having specific composition is coated on a substrate and the film formed is pattern-wise exposed, the component (C) present on the exposed area is thereby decomposed to generate an acid. By the succeeding heat treatment, the above generated acid crosslinks an acid-crosslinkable methylolated melamine compound, component (B), and makes it insoluble to an alkali developing solution, at the same time, the acid generated by the exposure diffuses to the substrate and also crosslinks and insolubilizes component (B) present near the substrate.
Thus in the present invention, even if a light is intercepted by a black pigment and does not reach the interface between the substrate and the film, component (B) is crosslinked far to the interface between the film and the substrate only by the exposure of the film surface and can be insolubilized to a developing solution. As a result, a black matrix containing a black pigment in high concentration can be formed.
Further, in black pigments so far been used, there have been such problems as an alkali-insoluble substance is formed by merely blending, coating and drying a black pigment with components (A), (B) and (C), and the composition becomes substantially developing solution-insoluble and patterning cannot be effected. However, the black matrix-forming material containing components (A), (B), (C), (D) and (E) in the present invention does not cause such problems.
In the first place, an alkali-soluble resin obtained by the condensation reaction of phenols containing at least cresol with aldehydes, which is component (A) of the black matrix-forming material for the color liquid crystal display according to the present invention, is described below.
In the present invention, as the above resin, resol resins or novolak resins obtained by the condensation reaction of phenols containing at least cresol with aldehydes are preferably used.
As alkali-soluble resins obtained by the condensation reaction of phenols containing at least cresol with aldehydes, resins obtained by the reaction of phenols containing 50 mol% or more of o-, m- or p-cresol with aldehydes are preferably used.
Examples of phenols which may be contained other than cresol include o-methoxyphenol, m-methoxyphenol, o-ethylphenol, m-ethylphenol, p-ethylphenol, 3,5-dimethoxyphenol, 2-methoxy-4-methylphenol, o-propoxyphenol, o-butoxyphenol, 3,4,5-trimethylphenol, o-vinylphenol, and m-phenylphenol.
Examples of aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, phenylaldehyde, &agr;-phenylpropylaldehyde, &bgr;-phenylpropylaldehyde, and o-hydroxybenzaldehyde. Among these, formaldehyde is preferred.
Resins obtained by the reaction of o-, m- or p-cresol or mixtures of them with formaldehyde are preferably used in the present invention.
These resins preferably have weight average molecular weight of from 500 to 20,000, and more preferably from 1,000 to 15,000.
The content of alkali-soluble resin component (A) in the black matrix-forming ma
Dan Shigeyuki
Mouri Taizo
Suzuki Nobuo
Fujifilm Olin Co., Ltd.
McPherson John A.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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