Radiation imagery chemistry: process – composition – or product th – Diazo reproduction – process – composition – or product – Composition or product which contains radiation sensitive...
Reexamination Certificate
1999-05-14
2004-04-27
Chu, John S. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Diazo reproduction, process, composition, or product
Composition or product which contains radiation sensitive...
C430S025000, C430S028000, C430S196000, C430S197000
Reexamination Certificate
active
06727034
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a photosensitive composition having exceptionally high sensitivity and high resolution and to technologies for fabrication of a black matrix and phosphor screen for a color picture tube using the same.
BACKGROUND ART
Black matrices for a color picture tube are generally fabricated in accordance with the following procedure:
(1) coating a glass panel all over with a water-soluble photosensitive composition,
(2) exposing the coated panel to ultraviolet light through a photomask to insolubilize the exposed areas against water,
(3) removing the unexposed areas by water spray to form a resist pattern,
(4) applying a dispersion of a black substance such as graphite,
(5) decomposing the resist pattern with an oxidizing agent, and
(6) removing the decomposition product by water spray.
Since this process involves many steps and time-consuming, a shortening of the process, particularly of the UV exposure step which is rate-determining, has been required.
As photosensitive compositions for use in the process to resolve the problem,
(1) a photosensitive composition comprising a polyvinylpyrrolidone and a water-soluble azide compound (Japanese Kokai Publication Sho-48-79970),
(2) a photosensitive composition comprising an acrylamide-diacetoneacrylamide copolymer and a water-soluble azide compound (Japanese Kokai Publication Sho-50-33764), and
(3) a photosensitive composition comprising an acrylamide-diacetoneacrylamide-acryloylmorpholine copolymer and a water-soluble azide compound (Japanese Kokai Publication Hei-6-51509), among others, have heretofore been proposed.
Meanwhile, phosphor screens for a color picture tube are manufactured by subjecting a glass panel having a black matrix formed thereon to the following sequence of steps:
(1) coating the whole surface of the glass panel with three kinds of photosensitive compositions each comprising a suspension of one of three phosphors corresponding to the primaries of red, green and blue,
(2) exposing the coated surface to ultraviolet light through a photomask to insolubilize the exposed areas against water, and
(3) removing the unexposed areas by water spray, the above series of steps being carried out for each of the three primary phosphors, finally followed by heating the coated panel within the air to oxidatively decompose and remove the organic component.
However, because photosensitive compositions containing a noxious chromium compound are used, this conventional process has disadvantages that the operation and equipments for removing chromium from the waste liquor are required for protection of the environment and that because of the poor aging resistance of the photosensitive components, the so-called dark reaction proceeds gradually, for example during storage, even when the phosphor screen is not directly exposed to ultraviolet light. An additional problem is that chromium tends to remain in the phosphor pattern after said decomposition and removal of organic matter and cause coloration of the phosphor screen or interfere with emissions from the phosphors to reduce the luminance of the color picture tube. In view of those disadvantages, development of chromium-free photosensitive compositions has been needed.
As phosphor-containing photosensitive compositions for use in the process with a view to overcoming the above disadvantages, the followings have heretofore been proposed:
(4) a phosphor-containing photosensitive composition comprising a water-soluble polymer, such as polyacrylamide or polyvinylpyrrolidone, and a water-soluble azide compound (Japanese Kokai Publication Sho-49-43569),
(5) a phosphor-containing photosensitive composition comprising a water-soluble polymer, such as polyvinyl alcohol or polyvinylpyrrolidone, and a water-soluble diazo compound (Japanese Kokai Publication Sho-49-100955), and
(6) a phosphor-containing photosensitive composition comprising an aqueous solution of a water-soluble styrylpyridinium compound (Japanese Kokai Publication Sho-60-71682), among others.
However, all the above-mentioned photosensitive compositions (1) to (6) are not so sufficiently sensitive to low-illuminance levels of exposure light that if the illuminance drops in the course of manufacture of large-sized cathode-ray tubes or high-definition tubes, the exposure time will be considerably protracted to result in decrease in productivity. Moreover, an additional number of exposure units must be installed but this leads to disadvantages in respect of machine space, equipment maintenance, and cost of equipments.
Furthermore, in the case of the above-mentioned photosensitive compositions (4) to (6) for use in the fabrication of phosphor screens, the light-sensitive components are of poor aging resistance, which inavoidably results in degradation due to the dark reaction and moreover may cause troubles and loss of yield, during continuous use in a picture tube production line.
SUMMARY OF THE INVENTION
The inventors have made a thorough analysis of the above drawbacks and study for resolving these problems of known photosensitive compositions for a black matrix and phosphor screen of a color picture tube and have reached the present invention discovering that a photosensitive composition comprising a vinyl polymer comprising a recurring unit derived from a monomer containing a functional group having a frontier electron density of not less than 0.067 and an azide compound and/or diazo compound (B) provides for exceptionally high sensitivity leading to a drastic reduction in exposure time as well as high aging resistance. This, according to this invention, is provided a photosensitive composition comprising 70 to 99 weight % of a vinyl polymer (A) comprising recurring units derived from a monomer (a) of the following general formula (1) wherein the functional group represented by Q has a frontier electron density of not less than 0.067 as computed in accordance with the following equation and 1 to 30 weight % of at least one photosensitive compound (B) selected from the group consisting of azide compounds and diazo compounds.
H
2
C═CH—X—Q (1)
[wherein X is selected from the group consisting of a direct bond, a 1,4-phenylene group, a sulfonyl group, a methylene group, and an alkylene group of 2 to 5 carbon atoms (said methylene and alkylene groups may respectively have one ether, carbonyl, carboxyl, amide or urea group). Q represents a functional group selected from the group consisting of —NH—R, —COCH
2
COCH
3
, and —SO
2
NH
2
. R represents a residue selected from the group consisting of —CHO, —H (hydrogen), alkyl of 1 to 6 carbon atoms (said alkyl may have one hydroxyl, ether, amino, nitro, cyano, carbonyl, carboxyl, amide, or urea group), —NH
2
, —COOH, —CH
2
CH
2
OH, —CH
2
CH
2
NH
2
, —CONH
2
and —CONHCH
3
.]
Frontier electron density=2×(Atomic orbital coefficient in lowest unoccupied molecular orbital (LUMO))
2
In another aspect of the invention, is provided a photosensitive composition comprising 70 to 99 weight % of a vinyl polymer (A1) comprising recurring units derived from a monomer (a1) containing a functional group having a frontier electron density of not less than 0.067 and a solubility parameter of 8.6 to 11.0 and 1 to 30 weight % of at least one photosensitive compound (B) selected from the group consisting of azide compounds and diazo compounds.
The present invention further provides a photosensitive composition comprising 30 to 98 weight % of a photosensitive composition and 2 to 70 weight % of at least one water-soluble polymer (C), having a weight average molecular weight of not less than 1000, and being selected from the group consisting of vinylpyrrolidone polymers, (meth)acrylamide-diacetone(meth)acrylamide polymers, N,N-dimethylaminoethyl (meth)acrylate polymers, 3-sulfopropyl (meth)acrylate polymers inclusive of their salts, N,N-dimethylaminopropyl(meth)-acrylamide polymers, 2-(meth)acrylamide-2-methylpropanesulfonic acid polymers inclusive of their salts, and styrenesulfonic acid polymers inclusive of their salts.
In a fu
Ogiso Naohito
Watanabe Tetsuya
Yamada Tetsuya
Chu John S.
Connolly Bove & Lodge & Hutz LLP
Sanyo Chemical Industries Ltd.
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