JPH10333322A - Photosensitive electrically conductive paste and production of electrode for plasma display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a black electrode required to enhance contrast and colorimetric purity. SOLUTION: This photosensitive electrically conductive paste consists of electrically conductive fine metal particles and org. components including a photosensitive compd. The fine metal particles contain 0.5-5 wt.% at least one metal selected from among Ru, Cr, Fe, Co, Mn and Cu or oxide of the metal. When the paste is applied to a substrate in 5-30 μm thickness and fired, the irritation value Y of color is in the range of 1-30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the preparation of electrodes for a plasma display and a photosensitive paste used therefor.

[0002]

2. Description of the Related Art Plasma display panels (PDPs)
Since they can display at a higher speed than a liquid crystal panel and can be easily made larger, they have permeated OA equipment and public information display devices. Further, progress in the field of high-definition television is highly expected.

With the expansion of such applications, attention has been paid to color PDPs having delicate and many display cells. PDPs use a small gap formed between two glass substrates, a front panel and a rear panel, as a discharge space to generate a plasma discharge between an anode and a cathode electrode. The display is performed by causing the generated ultraviolet light to be emitted to a phosphor provided in the discharge space to emit light. In this case, the electrodes are arranged in stripes on the front plate and the back plate respectively, a plurality of electrodes are parallel, the electrodes on the front plate and the electrodes on the back plate oppose each other with a slight gap, and are perpendicular to each other. It is formed as follows. PD
Among the P, a surface discharge type PDP having a three-electrode structure suitable for color display using a phosphor includes a plurality of pairs of display electrodes adjacent to each other in parallel and a plurality of address electrodes orthogonal to each pair of electrodes. And However, the rear plate has barriers to prevent light crosstalk and secure discharge space.
It is formed in the space between the electrodes.

[0004] Among the above-mentioned electrodes, for the electrodes on the front plate, there is a demand for a technique for blackening to improve the contrast of the display screen. For example, JP-A-61-176035
In Japanese Patent Application Laid-Open No. Hei 4-272634, a method is proposed in which a blackened silver paste is patterned on a glass substrate by a printing method. In the printing method, a conductive paste such as a silver paste is printed on a glass substrate using a print mask corresponding to the electrode pattern, and then fired to complete the electrode pattern. However, in the screen printing method, even if the mask pattern accuracy, squeeze hardness, printing speed, and dispersibility are optimized, the width of the electrode pattern cannot be reduced to 60 μm or less, and there is a limit in forming a fine pattern. . Further, in the screen printing method, since the accuracy of the print mask depends on the accuracy of the mask plate making, the size error of the mask pattern increases when the size of the print mask increases. Therefore, in the case of a PDP having a large area of 30 inches or more, it is increasingly technically difficult to produce a high-definition PDP.

In order to blacken the silver paste, a method is used in which silver is mixed with a metal oxide such as iron, chromium, nickel, ruthenium or the like in an equal amount or more with silver. However, this method significantly increases the resistance of the electrodes,
It is necessary to increase the thickness of the electrode and to form a two-layer structure of a black electrode and a normal white electrode. When the thickness of the electrode is increased, the surface flatness of the dielectric layer printed on the electrode cannot be guaranteed, and the two-layer structure has a problem that the process becomes complicated.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to form a black electrode for a plasma display or a plasma addressed liquid crystal display having a low resistance value and a high blackness.

[0007]

An object of the present invention is to provide a photosensitive conductive paste comprising conductive metal fine particles and an organic component containing a photosensitive compound, wherein Ru, Cr, and the like are contained in the conductive metal fine particles. At least one metal selected from the group consisting of Fe, Co, Mn, and Cu or an oxide thereof at 0.5 to 5
% Of the paste and 5 to 30 μm of this paste on the substrate.
m, and the color stimulus value Y when fired is 1-3
This is achieved by a photosensitive conductive paste characterized by being in the range of 0.

Another object of the present invention is to provide Ru, Cr, F
e, a conductive paste containing a conductive metal containing 0.5 to 5% by weight of at least one metal selected from the group consisting of Co, Mn, and Cu or an oxide thereof is applied to the substrate and fired. And a thickness of 5 to 30 μm, and a color stimulus value Y of 1 to 30 is formed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The electrode of the present invention has a low resistance value,
In addition, it is important that the color stimulus value Y is 1 to 30 with a thickness of 5 to 30 μm so that the display screen is sufficiently blackened to improve the contrast of the display screen.

The tristimulus value XYZ of the light source color and the chromaticity coordinates x, y, z obtained therefrom are described in 6.2 of JIS (Japanese Industrial Standards) Z 8722 (additional item of measured value), J
8.2 of ISZ 8717 (Display of annex to measured values)
6.2 (Additions to the measured values), JIS Z8701
(Color display method-XYZ color system and XYZ color system).

The present invention relates to a method for producing Ag, A in a photosensitive conductive paste.
1, Ru, Cr, Fe, Co, Mn, and C in conductive fine metal particles (metal group A) such as 1, Ni, Au, Pd, and Pt.
By adding or coating a metal such as u (metal group B) or a metal oxide thereof, the metal fine particles are blackened, and a black electrode pattern can be formed.

The blackening metal used at this time is R
By including at least one, and preferably three or more of the metals of u, Cr, Fe, Co, Mn, Cu, and Ni or oxides thereof, blackening is possible. In particular, Ru
The black pattern can be formed by containing 0.5 to 5% by weight of each of the above oxides. In order to color black, the metal fine particles of the metal group A may be coated with a metal or a metal oxide of the metal group B.

After the metal or metal oxide of metal group B is chemically plated on the surface of the fine metal particles of metal group A, 400 to 5
By baking at 00 ° C. for 30 minutes to several hours, blackening of the fine particles becomes possible. Specifically, the fine particles of the metal group A are dispersed in an aqueous solution of a desired metal salt or metal complex, and a reducing agent is added to the dispersant to precipitate the metal dissolved in the aqueous solution, followed by firing. By doing so, the precipitated metal is oxidized to black.

When the amount of the metal oxide added is small by firing, the metal oxide powder adheres uniformly and to the surface of the fine particles of the metal group A. When the amount of addition is large, it is uniformly coated and a thin film is formed. At this time, the metal fine particles used preferably have an average particle size of 0.5 to 5 μm from the viewpoint of ease of coating.

The metal salt or metal complex to be used is a salt or complex of the above-mentioned metal group B, and is not particularly limited as long as it is water-soluble. For example, halide, cyanide, sulfate, nitrate, ammine complex, nitrosyl complex, carbonyl complex Complexes and aqua complexes are preferred. In particular, for example, in the case of Ru, 2RuCl ₂ (OH) .7NH ₃ .3H ₂ O, RuO ₂
(NH ₃ ) ₂ (OH) ₂ , Na ₂ RuO ₄ , K ₂ RuO ₄ , R
_{b 2 RuO 4, Cs 2 RuO} 4, (NH 4) 2 RuO 4, Mg 2
RuO ₄ , Ca ₂ RuO ₄ , Sr ₂ RuO ₄ , Ba ₂ Ru
O ₄ , Ag ₂ RuO ₄ , Ru (NO) Cl ₂ .H ₂ O, Ru
(NO) Br ₂ .H ₂ O and Ru (NO) I ₃ are preferred.

The metal or metal oxide of the metal group B to be coated is 0.5 to 5% by weight based on the amount of the fine particles of the metal group A, and the blackness, the pattern forming property, the resistance value and the sintering property are determined. This is important because it is excellent in terms of point. If it is less than 0.5% by weight, the color becomes closer to white and the Y value becomes 30 or more, so that there is no effect in improving the contrast. If it is greater than 5% by weight,
It is not preferable because the sinterability decreases and the resistance value increases.
Further, the blackness becomes too strong, so that the ultraviolet rays do not reach the lower portion, and the pattern formability decreases, which is not preferable.

It is preferable that the conductive metal fine particles of the metal group A have a small theoretical resistance value, such as Ag, Al, Ni, Au, Pd,
Pt or the like is used, but Ag, Al, N
It is preferable to use i.

The shape of the conductive metal fine particles used in the present invention is not particularly limited. However, it is preferable to form granular or spherical particles having a large tap density since a denser conductive film has a lower resistance. These tap densities are 2g / c
Desirably, it is at least m ³ . The average particle size of the metal fine particles is selected in consideration of the shape of the pattern to be produced, but those having a diameter of 0.1 to 5 μm maintain good pattern formability, and have a smooth electrode surface and straight line edges. It is preferably used for When the thickness is 0.1 μm or less, since the gap between the particles is intricate, the exposed light does not reach the glass substrate, and pattern formation becomes impossible. If the thickness is 5 μm or more, a pattern can be formed, but the particles are too coarse to maintain the flatness of the electrode film, and furthermore, the distance between the particles is so large that there is a problem of disconnection after firing. A more preferred particle size is 1.5 to 3 μm
It is.

The photosensitive conductive paste contains one or more glass fine particles (glass frit) in order to enhance the adhesion to the substrate.
It can be added in a range of 0% by weight or less. Even without the addition of glass particles, the electrode pattern is in close contact with the substrate, but has a weak adhesive force and is easily peeled off by vibration, impact, or the like.
In particular, a low-temperature fired substrate such as a glass substrate is fired at a temperature of 600 ° C. or lower, so that the metal fine particles do not sinter completely, resulting in insufficient adhesion. The glass fine particles have an effect as a sintering aid, and also have an effect of increasing the adhesive force at the interface between the electrode and the substrate. However, if the addition amount of the glass fine particles exceeds 10% by weight, the adhesive force is already sufficient and does not change, but only the resistance value increases, which is not preferable. At less than 10% by weight, the adhesive strength increases in proportion to the amount of the added glass particles,
The specific resistance value is also 5 times or less that when no glass fine particles are added, and can be practically used. More preferably 0.5 to 3% by weight
It is.

The thermal softening point of the glass particles must be lower than the firing temperature. In order to exhibit the above effects, it is optimal that the temperature is lower by 0 to 100 ° C. than the firing temperature. Since the firing temperature on the glass substrate is 540 to 620 ° C, the thermal softening point of the glass fine particles is preferably 470 to 600 ° C. When the heat softening point is 600 ° C. or higher, the glass fine particles do not melt, so that the effect of addition is not observed. When the temperature is 470 ° C. or lower, the glass fine particles soften quickly, so that the glass fine particles are separated at the interface of the substrate, and the effect as a sintering aid is lost. More preferably, it is 500 to 550 ° C.

The average particle diameter of the glass fine particles is preferably the same as or slightly smaller than that of the metal fine particles.
Is preferred. If the average particle size is larger than 5 μm, the fine particles larger than the metal fine particles undesirably hinder the conduction of the electrodes, increase the line resistance, and eventually cause the disconnection of the electrode lines. If it is smaller than 0.1 μm, it flows during firing and gathers at the interface of the substrate, which is not preferable. Preferably it is 0.5 to 1.5 μm.

The details regarding the organic component of the photosensitive paste of the present invention will be described below. When used for an electrode of a plasma display or a plasma addressed liquid crystal display, it is preferable that the organic component is 40% by weight or less of the paste. When the content is 40% by weight or more, the firing shrinkage rate becomes large, which causes disconnection of the electrode, which is not preferable.
In addition, since the gap between the metallic fine particles is increased, the resistance is increased, which is not preferable.

The glass fine particles are preferably a composition containing the following oxides. It is preferable that silicon oxide is blended in the glass in a range of 3 to 60% by weight. If the content is less than 3% by weight, the denseness, strength and stability of the glass layer are reduced, and the coefficient of thermal expansion deviates from desired values, so that a mismatch with the glass substrate is likely to occur. By setting the content to 60% by weight or less, the thermal softening point is lowered, and sufficient baking on a glass substrate becomes possible.

Boron oxide is 5 to 50% by weight in the glass.
The electrical, mechanical and thermal properties such as electrical insulation, strength, coefficient of thermal expansion, and denseness of the insulating layer can be improved by blending in the range. If it exceeds 50% by weight, the stability of the glass will decrease.

It can be obtained by using a glass powder containing 3 to 20% by weight of at least one of lithium oxide, sodium oxide and potassium oxide, but an oxide of an alkali metal such as lithium, sodium and potassium is added. The amount is 20% by weight or less, preferably 1% by weight.
By setting the content to 5% by weight or less, the stability of the paste can be improved. Further, since the glass transition point and the glass softening point can be lowered, low-temperature firing becomes possible.

By using a glass powder containing at least one of bismuth oxide, lead oxide and zinc oxide in a glass in an amount of 5 to 50% by weight, a photosensitive glass paste capable of forming partition walls on a glass substrate by low-temperature firing can be obtained. Obtainable. If it exceeds 50% by weight, the heat-resistant temperature of the glass becomes too low, and it is difficult to bake the glass on a glass substrate. In particular, using glass containing 5 to 50% by weight of bismuth oxide has advantages such as a long pot life of the paste.

It is preferable to contain 50% by weight or more containing the above composition.

In addition, a glass containing both a metal oxide such as lead oxide, bismuth oxide and zinc oxide and an alkali metal oxide such as lithium oxide, sodium oxide and potassium oxide enables a thermal treatment at a lower alkali content. Control of softening temperature and linear thermal expansion coefficient becomes easy.

The hardness and workability are improved by adding aluminum oxide, barium oxide, calcium oxide, magnesium oxide, zinc oxide, zirconium oxide, etc., particularly aluminum oxide, barium oxide and zinc oxide to the glass fine particles. However, from the viewpoint of controlling the thermal softening point and the coefficient of thermal expansion, the content is preferably 40% by weight or less, more preferably 25% by weight or less. The amount of the inorganic fine particles used in the photosensitive conductive paste,
It is preferably 60 to 95% by weight based on the sum of the inorganic fine particles and the organic component.

If it is less than 60% by weight, the shrinkage during firing becomes large, which causes disconnection and peeling of the partition walls.
Not preferred. In addition, many organic components are burned off during firing, so that voids are easily generated, which is not preferable. Further, the pattern is likely to be thickened and a residual film is likely to occur during development. If it is greater than 95% by weight, apply the paste to the substrate,
At the time of drying, voids are generated, and the pattern forming property cannot be obtained.

When used for an electrode of a plasma display, a pattern is formed on a glass substrate having a low glass transition point and a low thermal softening point.

The organic component contains a photosensitive component selected from at least one of a photosensitive monomer, a photosensitive oligomer, and a photosensitive polymer, and further includes a binder, a photopolymerization initiator, an ultraviolet absorber, if necessary. Additive components such as sensitizers, sensitization aids, polymerization inhibitors, plasticizers, thickeners, organic solvents, antioxidants, dispersants, defoamers, and organic or inorganic suspending agents may also be added. Done.

The photosensitive component includes a photo-insolubilizing type and a photo-solubilizing type. The photo-insolubilizing type includes: (A) a functional monomer having at least one unsaturated group or the like in the molecule. (B) those containing photosensitive compounds such as aromatic diazo compounds, aromatic azide compounds, and organic halogen compounds. (C) So-called diazo resins such as condensates of diazo amines and formaldehyde. And others.

Examples of the photo-soluble type include: (D) a complex of a diazo compound with an inorganic salt or an organic acid, and a compound containing a quinone diazo compound; and (E) a quinone diazo compound combined with an appropriate polymer binder. For example, phenol, naphthoquinone-1,2-diazide-5-sulfonic acid ester of a novolak resin, and the like.

As the photosensitive component used in the present invention, all of the above can be used. As the photosensitive component which can be easily used as a photosensitive paste by mixing with an inorganic powder, the photosensitive component (A) is preferable.

The photosensitive monomer is a compound containing a carbon-carbon unsaturated bond, and specific examples thereof include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, and sec-butyl. Acrylate, sec-
Butyl acrylate, iso-butyl acrylate, te
rt-butyl acrylate, n-pentyl acrylate, allyl acrylate, benzyl acrylate, butoxyethyl acrylate, butoxytriethylene glycol acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, 2-ethylhexyl acrylate, glycerol acrylate, glycidyl acrylate Heptadecafluorodecyl acrylate, 2-hydroxyethyl acrylate, isobonyl acrylate, 2-hydroxypropyl acrylate, isodexyl acrylate, isooctyl acrylate, lauryl acrylate, 2-
Methoxyethyl acrylate, methoxyethylene glycol acrylate, methoxydiethylene glycol acrylate, octafluoropentyl acrylate, phenoxyethyl acrylate, stearyl acrylate, trifluoroethyl acrylate, allylated cyclohexyl diacrylate, 1,4-butanediol diacrylate, 1,3-butylene Glycol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, ditrimethylolpropane tetraacrylate, glycerol diacrylate, methoxide Shi of cyclohexyl diacrylate, neopentyl glycol diacrylate, propylene glycol diacrylate, polypropylene glycol diacrylate, triglycerol diacrylate,
Trimethylolpropane triacrylate, acrylamide, aminoethyl acrylate, phenyl acrylate, phenoxyethyl acrylate, benzyl acrylate, 1-naphthyl acrylate, 2-naphthyl acrylate, bisphenol A diacrylate, diacrylate of bisphenol A-ethylene oxide adduct,
Diacrylates of bisphenol A-propylene oxide adducts, acrylates such as thiophenol acrylate and benzyl mercaptan acrylate, and monomers in which 1 to 5 hydrogen atoms of these aromatic rings have been substituted with chlorine or bromine atoms, or Styrene, p-
Methylstyrene, o-methylstyrene, m-methylstyrene, chlorinated styrene, brominated styrene, α-methylstyrene, chlorinated α-methylstyrene, brominated α-methylstyrene, chloromethylstyrene, hydroxymethylstyrene, carboxy Methyl styrene, vinyl naphthalene, vinyl anthracene, vinyl carbazole, and those obtained by changing some or all of the acrylate in the molecule of the above compound to methacrylate, γ-methacryloxypropyltrimethoxysilane, 1-vinyl-2-pyrrolidone, etc. Is mentioned. In the present invention, one or more of these can be used.

In addition to these, the developability after exposure can be improved by adding an unsaturated acid such as an unsaturated carboxylic acid. Specific examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetic acid, and acid anhydrides thereof.

The content of these monomers is preferably 5 to 30% by weight based on the sum of the glass powder and the photosensitive component.
Outside of this range, the pattern formability deteriorates and the hardness becomes insufficient after curing.

As the binder, polyvinyl alcohol, polyvinyl butyral, methacrylate polymer, acrylate polymer, acrylate ester
Examples include methacrylate copolymers, α-methylstyrene polymers, and butyl methacrylate resins.

An oligomer or polymer obtained by polymerizing at least one of the compounds having a carbon-carbon double bond described above can be used. During the polymerization, the copolymer may be copolymerized with another photosensitive monomer so that the content of the photoreactive monomer is 10% by weight or more, more preferably 35% by weight or more.

As a monomer to be copolymerized, the developability after exposure can be improved by copolymerizing an unsaturated acid such as an unsaturated carboxylic acid. Specific examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetic acid, and acid anhydrides thereof.

The acid value (AV) of the thus obtained polymer or oligomer having an acidic group such as a carboxyl group in the side chain is preferably 50 to 180, more preferably 70 to 140. When the acid value is less than 50, the allowable development width becomes narrow. On the other hand, if the acid value exceeds 180, the solubility of the unexposed portion in the developing solution decreases, so that if the developing solution concentration is increased, peeling occurs up to the exposed portion, making it difficult to obtain a high-definition pattern.

By adding a photoreactive group to the polymer or oligomer described above to a side chain or a molecular terminal, the polymer or oligomer can be used as a photosensitive polymer or photosensitive oligomer having photosensitivity. Preferred photoreactive groups are those having an ethylenically unsaturated group. Examples of the ethylenically unsaturated group include a vinyl group, an allyl group, an acryl group, and a methacryl group.

A method for adding such a side chain to an oligomer or a polymer is to use an ethylenically unsaturated compound having a glycidyl group or an isocyanate group, an acrylic acid, or a mercapto group, an amino group, a hydroxyl group or a carboxyl group in the polymer. There is a method in which chloride, methacrylic chloride or allyl chloride is added to make an addition reaction.

Examples of the ethylenically unsaturated compound having a glycidyl group include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, glycidyl ethyl acrylate, crotonyl glycidyl ether, glycidyl crotonate, and glycidyl ether isocrotonic acid. .

Examples of the ethylenically unsaturated compound having an isocyanate group include (meth) acryloyl isocyanate and (meth) acryloylethyl isocyanate.

The ethylenically unsaturated compound having a glycidyl group or an isocyanate group, acrylic acid chloride, methacrylic acid chloride or allyl chloride is used in an amount of 0.05 to 0.05 to the mercapto group, amino group, hydroxyl group and carboxyl group in the polymer. It is preferable to add one molar equivalent.

The amount of the polymer component comprising the photosensitive polymer, the photosensitive oligomer and the binder in the photosensitive glass paste is excellent in terms of pattern formability and shrinkage after baking. It is preferably 5 to 30% by weight based on the sum of the components. Outside this range, it is not preferable because pattern formation is impossible or sinterability of the formed pattern deteriorates.

As specific examples of the photopolymerization initiator,
Benzophenone, methyl o-benzoylbenzoate, 4,
4-bis (dimethylamine) benzophenone, 4,4-
Bis (diethylamino) benzophenone, 4,4-dichlorobenzophenone, 4-benzoyl-4-methyldiphenylketone, dibenzylketone, fluorenone, 2,
2-diethoxyacetophenone, 2,2-dimethoxy-
2-phenyl-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone, pt-butyldichloroacetophenone, thioxanthone, 2-methylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, diethylthioxanthone, benzyl, Benzyl dimethyl ketanol, benzyl methoxyethyl acetal, benzoin, benzoin methyl ether, benzoin butyl ether, anthraquinone,
2-t-butylanthraquinone, 2-amylanthraquinone, β-chloroanthraquinone, anthrone, benzanthrone, dibenzosuberone, methyleneanthrone,
4-azidobenzalacetophenone, 2,6-bis (p
-Azidobenzylidene) cyclohexanone, 2,6-bis (p-azidobenzylidene) -4-methylcyclohexanone, 2-phenyl-1,2-butadione-2- (o
-Methoxycarbonyl) oxime, 1-phenyl-propanedione-2- (o-ethoxycarbonyl) oxime, 1,3-diphenyl-propanetrione-2- (o
-Ethoxycarbonyl) oxime, 1-phenyl-3-
Ethoxy-propanetrione-2- (o-benzoyl)
Oxime, Michler's ketone, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propanone, naphthalenesulfonyl chloride, quinoline sulfonyl chloride, N-phenylthioacridone, 4,4
-Azobisisobutyronitrile, diphenyl disulfide, benzothiazole disulfide, triphenylphorphine, camphorquinone, carbon tetrabromide, tribromophenylsulfone, benzoin peroxide and eosin,
Examples include a combination of a photoreducing dye such as methylene blue and a reducing agent such as ascorbic acid and triethanolamine. In the present invention, one or more of these can be used.

The photopolymerization initiator is used in an amount of 0.
In the range of 0.5 to 30% by weight, more preferably
5 to 20% by weight. If the amount of the polymerization initiator is too small, the photosensitivity becomes poor, and if the amount of the photopolymerization initiator is too large, the residual ratio of the exposed portion may be too small.

It is also effective to add an ultraviolet absorber. By adding a compound having a high ultraviolet absorption effect, a high aspect ratio, high definition, and high resolution can be obtained. UV absorbers composed of organic dyes, especially 35
Organic dyes having a high UV absorption coefficient in the wavelength range of 0 to 450 nm are preferably used. Specifically, azo dyes, aminoketone dyes, xanthene dyes, quinoline dyes, aminoketone dyes, anthraquinones, benzophenones, diphenylcyanoacrylates, triazines, p-aminobenzoic acid dyes and the like can be used. . Even when the organic dye is added as a light absorbing agent, it is preferable because deterioration of the insulating film characteristics due to the light absorbing agent can be reduced without remaining in the insulating film after firing. Among these, azo dyes and benzophenone dyes are preferred.

The amount of the organic dye added is 0 to the metal fine particles.
~ 0.5 parts by weight is preferred. Although a pattern can be formed without adding a dye, it is preferable to add 0.01 to 0.05% by weight because curing of an unexposed portion proceeds due to light scattering. In particular, since the metal fine particles used in the present invention are black, the absorption of the fine particles themselves is large, and the amount of the dye to be added may be small. If it exceeds 0.5% by weight, the ultraviolet ray is absorbed too much, so that only the surface layer of the paste is cured, and the pattern cannot be formed.

As an example of the method of adding the ultraviolet light absorbing agent composed of an organic dye, a method in which a solution in which an organic dye is dissolved in an organic solvent in advance and a method of kneading the solution at the time of preparing the paste may be used. After mixing the fine particles, a method of drying the fine particles can be used. By this method, a so-called capsule-like powder in which the surface of each of the metal fine particles is coated with an organic film can be produced and used.

In the present invention, F contained in the inorganic powder
e, Mn, Co, Na and trace amounts of Pb, Cd, M
In some cases, a metal such as g and an oxide react with a photosensitive component contained in the paste to cause the paste to gel in a short time, making application impossible. In order to prevent such a reaction, it is preferable to add a stabilizer to prevent gelation. As the stabilizer used, a triazole compound is preferably used. As the triazole compound, a benzotriazole derivative is preferably used. Among them, benzotriazole works particularly effectively. As an example of the surface treatment of the glass frit with benzotriazole used in the present invention, a predetermined amount of benzotriazole with respect to the inorganic powder was dissolved in an organic solvent such as methyl acetate, ethyl acetate, ethyl alcohol and methyl alcohol. Thereafter, the powder is immersed in the solution for 1 to 24 hours so that it can be sufficiently immersed. After immersion, preferably, the powder is naturally dried at 20 to 30 ° C., and the solvent is evaporated to prepare a powder which has been subjected to a triazole treatment. The ratio of the stabilizer used (stabilizer / inorganic powder) is preferably 0.05 to 5% by weight.

A sensitizer is added to improve the sensitivity. Specific examples of the sensitizer include 2,4-diethylthioxanthone, isopropylthioxanthone, 2,3-bis (4-diethylaminobenzal) cyclopentanone,
2,6-bis (4-dimethylaminobenzal) cyclohexanone, 2,6-bis (4-dimethylaminobenzal) -4-methylcyclohexanone, Michler's ketone,
4,4-bis (diethylamino) -benzophenone,
4,4-bis (dimethylamino) chalcone, 4,4-bis (diethylamino) chalcone, p-dimethylaminocinnamylidene indanone, p-dimethylaminobenzylidene indanone, 2- (p-dimethylaminophenylvinylene)- Isonaphthothiazole, 1,3-bis (4-
Dimethylaminobenzal) acetone, 1,3-carbonyl-bis (4-diethylaminobenzal) acetone,
3,3-carbonyl-bis (7-diethylaminocoumarin), N-phenyl-N-ethylethanolamine, N
-Phenylethanolamine, N-tolyldiethanolamine, N-phenylethanolamine, isoamyl dimethylaminobenzoate, isoamyl diethylaminobenzoate, 3-phenyl-5-benzoylthiotetrazole, 1-phenyl-5-ethoxycarbonylthiotetrazole and the like. Can be

In the present invention, one or more of these can be used. Some sensitizers can also be used as photopolymerization initiators. When a sensitizer is added to the photosensitive paste of the present invention, the amount is usually 0.05 to 10% by weight, more preferably 0.1 to 10% by weight, based on the photosensitive component. If the amount of the sensitizer is too small, the effect of improving the photosensitivity is not exhibited, and if the amount of the sensitizer is too large, the residual ratio of the exposed portion may be too small.

The polymerization inhibitor is added to improve the heat stability during storage. Specific examples of the polymerization inhibitor include hydroquinone, monoesterified hydroquinone,
N-nitrosodiphenylamine, phenothiazine, p-
t-butylcatechol, N-phenylnaphthylamine,
2,6-di-t-butyl-p-methylphenol, chloranil, pyrogallol and the like. When adding a polymerization inhibitor, the amount added, in the photosensitive paste,
Usually, it is 0.001 to 1% by weight.

Specific examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, polyethylene glycol, glycerin and the like.

It is effective to add an alkylene glycol-based antifoaming agent such as polyethylene glycol (molecular weight: 400 to 800) to reduce pores in the partition walls. Air bubbles in the paste can be reduced, and pores in the partition pattern before firing can be reduced. Antioxidants,
It is added to prevent oxidation of the acrylic copolymer during storage. Specific examples of antioxidants include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-4-ethylphenol,
2,2-methylene-bis- (4-methyl-6-t-butylphenol), 2,2-methylene-bis- (4-ethyl-6-t-butylphenol), 4,4-bis- (3
-Methyl-6-t-butylphenol), 1,1,3-
Tris- (2-methyl-6-t-butylphenol),
1,1,3-tris- (2-methyl-4-hydroxy-
t-butylphenyl) butane, bis [3,3-bis-
(4-hydroxy-3-t-butylphenyl) butyric acid] glycol ester, dilauryl thiodipropionate, triphenyl phosphite and the like. When adding an antioxidant, the amount added is usually
The addition amount is usually 0.001 to 1% by weight in the paste.
It is.

To adjust the viscosity of the solution, an organic solvent may be added to the photosensitive paste of the present invention. The organic solvent used at this time includes methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl ethyl ketone, dioxane, acetone, cyclohexanone, cyclopentanone, isobutyl alcohol, isopropyl alcohol, tetrahydrofuran, dimethyl sulfoxide, γ-butyrolactone, bromobenzene, Chlorobenzene, dibromobenzene, dichlorobenzene, bromobenzoic acid, chlorobenzoic acid, and the like, and an organic solvent mixture containing at least one of these are used.

The photosensitive paste is usually prepared by mixing various components such as an inorganic powder, an ultraviolet absorber, a photosensitive polymer, a photosensitive monomer, a photopolymerization initiator, a glass frit and a solvent so as to have a predetermined composition. The mixture is uniformly mixed and dispersed with three rollers or a kneading machine.

The viscosity of the paste is appropriately adjusted by the addition ratio of an inorganic powder, a thickener, an organic solvent, a plasticizer, a suspending agent, etc., but the range is from 2000 to 200,000 cps.
(Centipoise). For example, when applying to a glass substrate by a spin coating method other than the screen printing method, 200 to 5000 cps is preferable. In order to obtain a film thickness of 10 to 20 μm by applying once by the screen printing method, 5
10,000 to 200,000 cps is preferable.

Next, an example of performing pattern processing using a photosensitive paste will be described, but the present invention is not limited to this.

A photosensitive paste is applied to the entire surface or a part of a glass substrate, a ceramic substrate, or a polymer film. As the application method,
Methods such as screen printing, a bar coater, a roll coater, a die coater, and a blade coater can be used. The coating thickness is determined by the number of coatings, screen mesh,
It can be adjusted by choosing the viscosity of the paste.

Here, when applying the paste on the substrate,
Surface treatment of the substrate can be performed to enhance the adhesion between the substrate and the coating film. Examples of the surface treatment liquid include silane coupling agents such as vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, and tris-silane.
(2-methoxyethoxy) vinylsilane, γ-glycidoxypropyltrimethoxysilane, γ- (methacryloxypropyl) trimethoxysilane, γ (2-aminoethyl) aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane and the like, or organic metals such as organic titanium, organic aluminum and organic zirconium. The silane coupling agent or the organic metal is dissolved in an organic solvent, for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol or the like.
Use the one diluted to a concentration of 1 to 5%. Next, after applying this surface treatment liquid uniformly on the substrate with a spinner or the like, 8
Surface treatment can be performed by drying at 0 to 140 ° C. for 10 to 60 minutes.When applied on a film, after drying on the film, performing the next exposure step,
There is a method in which an exposure step is performed after the film is pasted on a glass or ceramic substrate.

After application, exposure is performed using an exposure device. The exposure is generally performed by a mask exposure using a photomask, as is performed by ordinary photolithography. As the mask to be used, either a negative type or a positive type is selected depending on the type of the photosensitive organic component.

Further, a method of directly drawing with a red or blue laser beam without using a photomask may be used.

As an exposure device, a stepper exposure device, a proximity exposure device, or the like can be used. In the case of performing a large-area exposure, after applying a photosensitive paste on a substrate such as a glass substrate, and performing the exposure while transporting, it is possible to expose a large area with an exposure machine having a small exposure area. it can.

The active light source used at this time is, for example,
Visible light, near-ultraviolet light, ultraviolet light, electron beam, X-ray, laser light, etc. are preferable. Among them, ultraviolet light is preferable. Etc. can be used. Among these, an ultra-high pressure mercury lamp is preferred.
Exposure conditions vary depending on the coating thickness, but 1 to 100 mW
Exposure is performed for 0.5 to 30 minutes using an ultra-high pressure mercury lamp with an output of / cm ² .

By providing an oxygen shielding film on the surface of the applied photosensitive paste, the pattern shape can be improved. As an example of the oxygen shielding film, a film of polyvinyl alcohol (PVA) or cellulose, or a film of polyester or the like can be given.

The PVA film is formed by uniformly applying an aqueous solution having a concentration of 0.5 to 5% by weight on a substrate by a method such as a spinner, and then drying at 70 to 90 ° C. for 10 to 60 minutes to evaporate water. Let me do it. In addition, it is preferable to add a small amount of alcohol to the aqueous solution because the coatability with the insulating film is improved and the evaporation is facilitated. A more preferred solution concentration of PVA is 1 to 3% by weight. Within this range, the sensitivity is further improved. The reason why the sensitivity is improved by the PVA application is presumed as follows. That is, when the photosensitive component undergoes a photoreaction, the presence of oxygen in the air is considered to hinder the photocuring sensitivity, but the presence of a PVA film is considered to improve the sensitivity during exposure because excess oxygen can be blocked. .

When a transparent film of polyester, polypropylene, polyethylene, or the like is used, there is a method in which the film is attached to the photosensitive paste after application.

After the exposure, development is carried out utilizing the difference in solubility between the photosensitive portion and the non-photosensitive portion in the developing solution. In this case, the development is carried out by an immersion method, a shower method, a spray method, or a brush method.

As the developer to be used, an organic solvent in which the organic components in the photosensitive paste can be dissolved can be used. Water may be added to the organic solvent as long as the solvent does not lose its solubility. When a compound having an acidic group such as a carboxyl group is present in the photosensitive paste, development can be performed with an aqueous alkali solution. As the alkaline aqueous solution, a metallic alkaline aqueous solution such as sodium hydroxide, sodium carbonate, calcium hydroxide aqueous solution, etc. can be used, but it is preferable to use an organic alkaline aqueous solution since the alkaline component can be easily removed during firing.

As the organic alkali, an amine compound can be used. Specific examples include tetramethylammonium hydroxide, trimethylbenzylammonium hydroxide, monoethanolamine, diethanolamine and the like. The concentration of the alkaline aqueous solution is usually 0.01 to 10% by weight, more preferably 0.1 to 5% by weight. If the alkali concentration is too low, the soluble portion is not removed, and if the alkali concentration is too high, the pattern portion may be peeled off and the non-soluble portion may be corroded, which is not preferable. The development temperature during development is preferably from 20 to 50 ° C. from the viewpoint of process control.

Next, firing is performed in a firing furnace. The firing atmosphere and temperature vary depending on the type of the paste and the substrate, but firing is performed in an atmosphere of air, nitrogen, hydrogen, or the like. As the firing furnace, a batch-type firing furnace or a belt-type continuous firing furnace can be used.

For pattern processing on a glass substrate,
The calcination is carried out at a temperature of 540 to 620 ° C. for 10 to 60 minutes.

A heating step at 50 to 300 ° C. may be introduced for the purpose of drying and preliminary reaction during each of the coating, exposure, development and baking steps.

[0079]

The present invention will be specifically described below with reference to examples. However, the present invention is not limited to this. The concentrations (%) in Examples and Comparative Examples are% by weight unless otherwise specified.

Example 1 As the black conductive metal fine particles, Ru
Using silver uniformly coated with O ₂ to 3% by weight,
A photosensitive conductive paste comprising metal fine particles and a photosensitive organic component was prepared. The paste was prepared by mixing and dissolving all photosensitive organic components, adding fine metal particles, and kneading the mixture with a kneading machine such as a three-roller. In addition,
Table 1 shows the used metal fine particles, and Table 2 shows the paste composition.

Next, a paste was printed on a 25 cm × 35 cm square soda glass substrate using a screen printer. Printing was performed on a 400-mesh screen, and the coating thickness was 10 μm. After printing, the solvent was dried at 100 ° C. for 30 minutes.

The exposure was carried out using an ultra-high pressure mercury lamp having an output of 50 mW / cm ² for 20 seconds. The photomask used at the time of exposure is a negative type, and is a chrome mask through which light to be cured is transmitted. The electrode pattern has a pitch of 140
A striped high-definition pattern having a line width of 40 μm was used.

The development was carried out in a shower of a 0.1% aqueous solution of monoethanolamine at 30 ° C., and portions not irradiated with light were removed. Then, the developer was washed away with a shower of pure water, and dried at 80 ° C. for 20 minutes.

The firing was carried out by raising the temperature at 250 ° C./hour and maintaining the maximum temperature at 580 ° C. for 15 minutes. Under the same conditions, a sample for pattern resolution test, a sample for measuring the blackness of the electrode film, and a sample for measuring the specific resistance were prepared, and the pattern resolution was observed, and the blackness and the specific resistance of the electrode film were measured. Regarding the resolution, the whole, surface, and cross section were observed with an electron microscope (SEM) photograph of the electrode pattern. Regarding the blackness of the electrode film,
Color computer (SM-7) manufactured by Suga Test Instruments Co., Ltd.
-CH) was used to measure the stimulus value Y. The specific resistance was measured and calculated by preparing a dedicated pattern.

The pattern formability was good, and the cross section of the electrode line was rectangular. The Y value was 5.0, and the blackness was very high. Further, the specific resistance was 10 μΩ / cm ² , which was practically usable.

Example 2 As blackened conductive metal fine particles, Fe particles
Preparation and evaluation were performed in the same manner as in Example 1 except that silver coated uniformly with 1% by weight of ₂ O ₃ was used.

The pattern formability was good, and the cross section of the electrode line was rectangular. The Y value was 10.0 and the blackness was high. The specific resistance value is 18 μΩ / cm ² ,
It was practical.

Example 3 As the black conductive metal fine particles, Cu
Preparation and evaluation were performed in the same manner as in Example 1 except that silver coated uniformly with O to 1% by weight was used.

The pattern formability was good and the cross section of the electrode line was rectangular. The Y value was 8.0 and the blackness was high. Further, the specific resistance value was 18 μΩ / cm ² , which was practically usable.

Example 4 As the black conductive metal fine particles, Mo
Preparation and evaluation were performed in the same manner as in Example 1 except that silver coated uniformly with O ₂ to 1% by weight was used.

The pattern formability was good, and the cross section of the electrode line was rectangular. The Y value was 12.0, and the blackness was high. The specific resistance value is 20 μΩ / cm ² ,
It was practical.

Example 5 As blackened conductive metal fine particles, Ru was applied to the surface of the fine particles.
Preparation and evaluation were performed in the same manner as in Example 1 except that aluminum coated uniformly with O ₂ at 3% by weight was used.

The pattern formability was good, and the cross section of the electrode line was rectangular. The Y value was 20.0, and the blackness was high. The specific resistance value is 25 μΩ / cm ² ,
It was practical.

Example 6 As blackened conductive metal fine particles, Ru was applied to the surface of the fine particles.
Preparation and evaluation were performed in the same manner as in Example 1 except that nickel coated uniformly with O ₂ to 3% by weight was used.

The pattern formability was good, and the cross section of the electrode line was rectangular. The Y value was 5.0, and the blackness was very high. The specific resistance value was 25 μΩ / cm ² , which was practically usable.

Comparative Example 1 Ru black conductive metal fine particles
Production and evaluation were performed in the same manner as in Example 1 except that silver coated uniformly with O ₂ to 10% by weight was used.

The pattern formability was good, and the cross section of the electrode line was rectangular. Further, the Y value was 3.0, and the blackness was high. However, the resistance value is 50 μΩ / cm
² , which was not practical.

Comparative Example 2 As blackened conductive metal fine particles, Cu
Production and evaluation were performed in the same manner as in Example 1 except that silver coated uniformly with O to 10% by weight was used.

The pattern formability was good, and the cross section of the electrode line was rectangular. Further, the Y value was 3.0, and the blackness was high. However, the specific resistance value is 100 μΩ /
cm ² , which was not enough for practical use.

[0100]

[Table 1]

[Table 2] The abbreviations in the table are shown below.

X-4007: 40% methacrylic acid (MAA), 30% methyl methacrylate (MM
A) Photopolymer TPA having a weight average molecular weight of 43000 and an acid value of 95 obtained by subjecting a carboxyl group of a copolymer comprising A) and 30% styrene (St) to an addition reaction with 0.4 equivalent of glycidyl methacrylate (GMA). : Trimethylolpropane triacrylate MTPMP: 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1 DBP: dibutyl phthalate SiO ₂ : “Aerosil” Sudan: azo dye, C ₂₄ H ₂₀ N ₄ O γ-BL: γ-butyrolactone

[Table 3]

[0102]

By using the blackened photosensitive conductive paste of the present invention, a black electrode of a plasma display or a plasma addressed liquid crystal display having a low resistance value can be formed by a simple method.

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI H01J 9/02 H01J 9/02 F

Claims (11)

[Claims] 1. A photosensitive conductive paste comprising conductive metal fine particles and an organic component containing a photosensitive compound, wherein Ru, Cr, Fe, Co, Mn,
Stimulation of color when the paste contains 0.5 to 5% by weight of at least one metal selected from the group of Cu or an oxide thereof, and is applied to a substrate with a thickness of 5 to 30 μm and fired. A photosensitive conductive paste, wherein the value Y is in the range of 1 to 30. 2. The method according to claim 1, wherein at least one kind of metal or metal oxide selected from the group consisting of Ru, Cr, Fe, Co, Mn and Cu covers the surface of the conductive metal fine particles. 1. The photosensitive conductive paste of 1. 3. The conductive metal of Ag, Au, Pd, P
2. The paste according to claim 1, comprising at least one metal selected from the group consisting of t, Ni and Al. 4. The conductive metal fine particles have an average particle size of 0.1 to 0.1.
2. The photosensitive conductive paste according to claim 1, wherein the thickness is in a range of 5 [mu] m. 5. The photosensitive conductive paste according to claim 1, wherein the paste contains glass fine particles in a range of 10% by weight or less. 6. A glass powder having a glass transition point of 400 to 50.
2. The photosensitive conductive paste according to claim 1, wherein the glass has a softening point of 470 to 600 [deg.] C. 7. The photosensitive conductive paste according to claim 1, wherein the average particle size of the glass powder is in the range of 0.1 to 5 μm. 8. The photosensitive conductive paste according to claim 1, wherein the organic component contains 10 to 90% by weight of an oligomer or polymer having an unsaturated double bond and having a weight average molecular weight of 500 to 100,000. 9. The photosensitive conductive paste according to claim 1, which is used for a plasma display. 10. A conductive paste containing a conductive metal containing 0.5 to 5% by weight of at least one metal selected from the group consisting of Ru, Cr, Fe, Co, Mn and Cu or an oxide thereof. Coated on a substrate, baked, thickness 5-30μ
A method for manufacturing an electrode for a plasma display, wherein an electrode having a color stimulus value Y of 1 to 30 is formed. 11. The photosensitive conductive paste of claim 1 is applied on a substrate, patterned by photolithography, and then baked to have a thickness of 5 to 30 μm and a color stimulus value of 1 to 1.
A method for manufacturing an electrode for a plasma display, comprising forming 30 electrodes.