Radiation imagery chemistry: process – composition – or product th – Radiation modifying product or process of making – Screen other than for cathode-ray tube
Reexamination Certificate
2001-07-10
2003-11-04
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
Reexamination Certificate
active
06641960
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a photosensitive solution for forming a picture cell used in a color liquid crystal display apparatus, image pick-up tube and the like, and to a color filter formed by using the photosensitive solution. More particularly, it relates to a photosensitive solution capable of forming a picture cell excellent in transmittance and contrast, and to a color filter formed by using the photosensitive solution.
A color filter in a color liquid crystal display apparatus, image pick-up tube and the like is usually produced by forming picture cells of each of three primary colors, red, green and blue, on a substrate, such as glass plate, film plate, silicon wafer, or the like. Usually, a black matrix (a shielding layer) is formed in order to shield a light among the colored picture cells. A colored picture cell of each color can be formed according to the following method. A photosensitive solution dispersing a pigment of the color is applied uniformly by a spin coater on a substrate on which a shielding layer pattern was formed, then, the applied film is heated for drying (pre-bake) to obtain a dried film. Thereafter, the dried film is subjected to a patterning exposure, followed by developing and heating (post-bake) to obtain a colored picture cell. By repeating the above procedure for each color required in a color filter, a color filter having the required colors can be obtained. For forming a black matrix, a photosensitive solution containing a black pigment can be used.
In recent years, a saving liquid coater, such as those of slit and spin system and extrusion coaters, has been used as a coater used in a production of color filter. Such a saving liquid coater requires a smaller amount of photosensitive solution for coating it than a conventional spin coater. Therefore, it is economically advantageous. However, when such a saving liquid coater is used, a dried matter of the photosensitive solution-tends to adhere to the color filter, and yield of the color filter tends to lower. For preventing this problem, the dried colored matter adhered at the slit part is removed by washing the slit part with a solvent in prescribed times. However, the problem cannot be prevented sufficiently even when the washing is conducted very often, and more effective method is desired for improving the productivity.
The present inventors has conducted intensive studies on a solvent used in a photosensitive solution for forming a colored picture cell. As a result, they have found that by using a specific solvent, for the washing, which can dissolve, by immersing, a dried film formed from a photosensitive solution in a specific time, formation of the dried colored matter adhered to a color filter can be suppressed, frequency of the washing can be reduced, and the productivity can be improved. The present invention was completed based on this finding.
SUMMARY OF THE INVENTION
The present invention provide a practically excellent photosensitive solution comprising a colorant, a binder, a photoactive compound and a solvent, wherein the solvent can dissolve a dried film formed from a photosensitive solution in 5 minutes or shorter when the dried film is immersed in the solvent, the amount of the solvent being 10 times by weight based on the amount of the dried film.
EMBODIMENT OF THE INVENTION
The colorant used in the photosensitive solution of the present invention can be at least one selected from pigments and dyes. The pigments and dyes can be organic colorants or inorganic colorants usually used in this field.
As such inorganic colorants, metal compounds such as metal oxides and metal complex salts can be exemplified. Specific examples thereof include a metal oxide and a complex metal oxide of iron, cobalt, aluminum, cadmium, lead, copper, titan, magnesium, chromium, zinc, antimony or the like. As such organic colorants, compounds classified in pigments in Colour index (The Society of Dyers and Clolurists) are preferably used. Specific examples of the organic colorants include compounds of the following colour index (C.I.) number, although organic colorants usable in the present invention are not limited to the compounds:
C.I. Acid red 73;
C.I. Direct red 1, 23, 89;
C.I. Pigment yellow 20, 24, 31, 53, 83, 86, 93, 94, 109, 110, 117, 125, 137, 138, 139, 147, 148, 150, 153, 154, 166 and 173;
C.I. Pigment orange 13, 31, 36, 38, 40, 42, 43, 51, 55, 59, 61, 64 65, and 71;
C.I. Pigment red 9, 97, 105, 122, 123, 144, 149, 166, 168, 176, 177, 180, 192, 215, 216. 224, 242, and 254
C.I. Pigment violet 14, 19, 23, 29, 32, 33, 36, 37 and 38;
C.I. Pigment blue 15 (15:3, 15:4, 15:6
), 21, 22, 28, 60 and 64:
C.I. Pigment green 7, 10, 15, 25, 36 and 47;
C.I. Pigment brown 28; and
C.I. Pigment black 1 and 7.
When the colorant is a pigment, the pigment can be, if necessary, subjected to a rosin treatment, a surface treatment using a pigment derivative having an acidic group or a basic group, or the like, a fine particle treatment such as the one by kneader fine particle method, a washing for removing impurities with an organic solvent, water or the like.
Such a colorant is used in an amount of preferably 5-60% by weight, more preferably 10-50% by weight base on the total solid contents of the photosensitive solution. If a colorant used for modifying color is used together, the above amount is the total of both colorants.
The binder polymer makes the unexposed part of the coated film alkali soluble and acts as a dispersing medium for a pigment. The binder polymer can be selected from various polymers used in this field. This binder polymer is preferably a copolymer having a carboxyl group. As the copolymer having a carboxyl group, particularly, copolymers obtained from a carboxyl group-containing monomer and other monomer copolymerizable therewith are preferably used.
The carboxyl group-containing monomer can be, for example, an unsaturated carboxylic acid having at least one carboxyl group in the molecule, such as an unsaturated monocarboxylic acid and unsaturated dicarboxylic acid. Specific examples thereof include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid and fumaric acid. These carboxyl group-containing monomers can be used each alone or In combination of two or more. The monomer copolymerizable with such carboxyl group-containing monomers is a compound having a polymerizable carbon-carbon unsaturated bond. Specific examples thereof include aromatic vinyl compounds such as &agr;-methylstyrene, vinyltoluene and the like, unsaturated carboxylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-hydroxylethyl (meth)acrylate, benzyl (meth)acrylate and the like, unsaturated aminoalkyl carboxylates such as aminoethyl acrylate and the like, unsaturated glycidyl carboxylates such as glycidyl (meth)acrylate and the like, vinyl carboxylates such as vinyl acetate and vinyl propionate and the like, vinyl cyanide compounds such as (meth)acrylonitrile and &agr;-chloroacrylonitrile, and the like. These monomers can also be used each alone or in combination of two or more. In this copolymer, the carboxyl group-containing monomer is used in an amount of preferably from 10 to 50% by weight, more preferably from 15 to 40% by weight based on the total amount of monomers.
Preferable specific examples of such copolymer having a carboxyl group include benzyl methacrylate/methacrylic acid copolymer, benzyl methacrylate/methacrylic acid/styrene copolymer, methyl methacrylate/methacrylic acid copolymer, methyl methacrylate/methacrylic acid/styrene copolymer and the like. These copolymer shaving a carboxyl group preferably have weight-average molecular weight measured by gel permeation chromatography converted to polystyrene of from 5000 to 400000, more preferably from 10000 to 300000. The binder resin is used in an amount of usually from 5 to 90% by weight, preferably from 20 to 70% by weight based on the total amount of all solid components (that is, amount of photosensitive solution excepting amount of solvent) in the photosens
McPherson John A.
Sumitomo Chemical Company Limited
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