JPH11111182A - Plasma display and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure the provision of highly accurate, large and clear images by setting the thickness of electrode formed on a substrate and the line width thereof in each specified range, setting the short-circuit fault not to be occurring at positions other than specified positions, preventing each substrate from being subjected to a fault of short-circuit over a specified number of its electrodes, and making the total number of short-circuit fault not to be more than those at the specified positions. SOLUTION: The thickness of an electrode formed on a substrate is made 1-10 μm and the line width thereof is made 20-200 μm, and also the positions of short-circuit fault is made not more than 5 positions. It is made that, per one sheet of substrate, there is no short-circuit fault over three or more electrodes and the total number of short-circuit fault over two or more electrodes is not more than 2 positions. The length per one electrode is made 200-2000 mm and the number of electrodes per one sheet of substrate is made 1200-10000. Photosensitive conductive paste is applied on the substrate and patternwise formed by the photolithograph method, and then baked to thereby form the electrode. Accordingly, it is possible to have a clear and high quality image without pin holes, voids and line breakage faults and a picture element faultls.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plasma display and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for miniaturization, high density, high definition, and high reliability in circuit materials and displays. As a result, the line width of electrodes and the pitch have become narrower. ing. Various repair (repair) methods have been proposed for electrode defects caused by the inclusion of foreign matter, dust, and the like, but an electrode having no defect is desired from the beginning in the manufacturing process.

[0003] Plasma display panel (PDP)
Since they can display at a higher speed and can be easily made larger in size than liquid crystal panels, they have permeated OA equipment and 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 a large number of fine display cells.
The PDP generates a plasma discharge between opposing anode and cathode electrodes in a discharge space provided between a front glass substrate and a rear glass substrate, and emits light from a gas sealed in the discharge space. The display is performed. In this case, the anode and cathode electrodes on the glass substrate are arranged in parallel with a plurality of linear electrodes, and the electrodes oppose each other via a small gap and cross each other. It is configured to be superimposed so as to face. Among the PDPs, 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

In the various electrode patterns described above, each electrode should originally be formed in an independent form. However, when a conductive substance such as an electrode material is attached to two or more adjacent electrodes, a short circuit occurs. It becomes a defect. When such a short-circuit defect occurs, the circuit material malfunctions,
Problems such as failure of the device due to abnormal current and ignition due to abnormal heat generation occur, and the display loses pixels and the like, and clear images cannot be obtained.

The address electrode is usually formed by printing a silver paste or the like on a glass substrate by using a printing mask having a mask pattern corresponding to the address electrode by a screen printing method, and then firing the silver paste. However, in screen printing, mask pattern accuracy, squeeze hardness,
Even if the printing speed, dispersibility, and the like are optimized, the width of the electrode pattern cannot be reduced to 100 μm or less, the electrode cross-section becomes a semi-cylindrical shape, and there is a limit in forming a fine pattern. In the screen printing method,
Since the precision of the print mask depends on the precision of the mask plate making, the larger the print mask, the larger the dimensional error of the mask pattern. For this reason, in the case of PDPs having a large area of 25 inches or more, it is increasingly technically difficult to produce high-definition PDPs.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-definition and large-sized plasma display panel capable of obtaining a clear image without a clear defect.

[0008]

An object of the present invention is to provide a plasma display having an electrode formed on a substrate, wherein the electrode has a thickness of 1 to 10 μm, a line width of 20 to 200 μm, and a short-circuit defect. This is achieved by a plasma display characterized by having no more than five locations.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The thickness of an electrode in the present invention is 1 to
It is necessary to be 10 μm, and the range of 2 to 5 μm is more preferable. When the thickness is less than 1 μm, pinholes and white spots are liable to occur, resulting in disconnection defects. When the thickness exceeds 10 μm, when a dielectric is formed on the electrode, stress concentrates on the interface between the electrode and the dielectric and cracks occur.

Further, the line width of the electrode needs to be 20 to 200 μm. More preferably, it is 20 to 80 μm. When the line width is reduced to less than 20 μm, the line resistance is extremely reduced and power consumption is increased. The line width is 20
If the width exceeds 0 μm, the end is turned up due to shrinkage during firing, and when a dielectric is formed on the electrode, stress concentrates on the end and a crack occurs in the dielectric.

The length of one electrode in the present invention is preferably 200 to 2000 mm. 200m
When the length is shorter than m, the size becomes too small and the function as a display cannot be sufficiently exhibited. Also, 200
If the length is longer than 0 mm, the line resistance increases and a voltage drop occurs between the end of the electrode and the end on the opposite side, resulting in an operation failure. The number of electrodes per substrate is 1200 to 1
Preferably, the number is 0000. If the number is reduced to less than 1200, when used as a display, the screen becomes too rough to exhibit a sufficient function. 10,000
When the number exceeds the number of books, the gap between the electrodes becomes narrow, and processing becomes difficult.

In the present invention, it is necessary that the number of short-circuit defects of the electrode is 5 or less. If the number of short defects exceeds five, when used as a display, the number of missing pixels increases, and a clear image cannot be obtained. In particular, in the case of a short-circuit defect extending over three or more adjacent electrodes,
This is not preferable because the device is likely to malfunction due to malfunction or abnormal current. If the number of short-circuit defects is five or less, the number of missing pixels is small, and it is possible to eliminate defects of the electrodes by repair. It is preferable that there is no short defect over three or more electrodes per substrate and that the total number of short defects over two or less electrodes is two or less.

The conductive powder used in the present invention is A
g, Au, Pd, Ni and Pt are preferable and include at least one selected from the group consisting of
A low-resistance conductor powder that can be baked at a temperature of 0 ° C. or less is used. These can be used alone or as a mixed powder. For example, Ag (80-98) -Pd (20-
2), Ag (90-98) -Pd (10-2) -Pt
(2-10), Ag (85-98) -Pt (15-2)
A mixed noble metal powder of a ternary system or a binary system (the above (in parentheses represents weight%)) is used.

The average particle size of these conductive powders is 1.0
４4.0 μm, more preferably 1.2-2.0 μm. When the average particle size is smaller than 1.0 μm, light does not smoothly pass through the printed film during exposure to ultraviolet light,
It becomes difficult to form a fine pattern having a line width of the electrode conductor of 60 μm or less. On the other hand, if the particle diameter is larger than 4.0 μm, the surface of the electrode pattern after printing becomes rough, and the pattern accuracy, thickness and dimensional accuracy of the thin film conductor of 10 μm or less decrease.

The specific surface area of the conductive powder is 0.3 to 2.5.
m ² / g, preferably 0.8
More preferably, the range is 1.5 m ² / g. If the specific surface area is less than 0.3 m ² / g, the accuracy of the electrode pattern is reduced. On the other hand, if it exceeds 2.5 m ² / g, the surface area of the powder becomes too large and the ultraviolet rays are scattered, and the exposure hardening is not sufficiently performed to the lower part, so that peeling occurs during development and the pattern accuracy is reduced.

The tap density of the conductive powder is 3 to 5 g.
/ Cm ³ . More preferably, 3.5 to
It is in the range of 5 g / cm ³ . When the tap density is in this range, the ultraviolet ray transmittance is good, and the electrode pattern accuracy is improved.
Further, a dense film having good leveling property can be obtained in the coating film after printing the paste.

The conductive powder may be in the form of particles (particles), polyhedrons, or spheres, but is preferably monodisperse particles that do not aggregate and are spherical. In this case, the spherical shape preferably has a sphericity of 90% by number or more. For the measurement of the sphericity, the powder was photographed with an optical microscope at a magnification of 300 times, and countable particles were counted, and the ratio of spherical particles was represented. When the shape is spherical, the scattering of ultraviolet light during exposure is very small, a highly accurate pattern can be obtained, and the irradiation energy can be reduced.

In the electrode of the present invention, the number of disconnection defects is one or less per 10 m of electrode length,
It is preferable that the number of disconnection defects per sheet is one or less from the display characteristics of the plasma display panel.

The photosensitive organic component used in the electrode of the present invention is an organic component containing a photosensitive compound in the photosensitive conductive paste.

With respect to the photosensitive conductive paste used for the electrode of the present invention, the content of the photosensitive compound is preferably at least 10% by weight of the photosensitive organic component from the viewpoint of sensitivity to light. More preferably, it is at least 30% by weight.

The photosensitive compound includes a photo-insolubilized type and a photo-solubilized type.
(1) those containing a functional monomer, oligomer or polymer having at least one unsaturated group in the molecule;
(2) those containing photosensitive compounds such as aromatic diazo compounds, aromatic azide compounds, and organic halogen compounds;
(3) So-called diazo resins, such as condensates of diazo-based amines and formaldehyde, and the like.

The photo-soluble type includes (4) a complex of a diazo compound with an inorganic salt or an organic acid, a compound containing quinone diazos, and (5) a quinone diazo compound combined with an appropriate polymer binder. For example, phenol, naphthoquinone 1,2-diazide of novolak resin
5-sulfonic acid ester, and the like.

In the present invention, all of the above can be used, but the above (1) is preferred in terms of ease of handling and quality design.

Specific examples of the photosensitive monomer having a functional group in the molecule include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, sec-butyl acrylate, -Butyl acrylate, tert-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 Acrylate, dipen Erythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, ditrimethylolpropane tetraacrylate, glycerol diacrylate, methoxylated cyclohexyl diacrylate, neopentyl glycol diacrylate, propylene glycol diacrylate, polypropylene glycol diacrylate, triglycerol diacrylate, triglycol Methylolpropane triacrylate, acrylamide, aminoethyl acrylate 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, and the like. .

Also, phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, 1-naphthyl (meth) acrylate, 2-naphthyl (meth) acrylate, bisphenol A di (meth) acrylate, bisphenol A -Di (meth) acrylate of ethylene oxide adduct, di (meth) acrylate of bisphenol A-propylene oxide adduct, 1-naphthyl (meth) acrylate, 2-naphthyl (meth) acrylate, thiophenol (meth) acrylate, benzyl Mercaptan (meth) acrylate-like acrylates, styrene, p
-Methylstyrene, o-methylstyrene, m-methylstyrene, α-methylstyrene, chloromethylstyrene,
Styrenes such as hydroxymethylstyrene, and some or all of the hydrogen atoms in these aromatic rings are chlorine,
Those substituted with bromine atoms, iodine or fluorine,
Further, methacrylate in which part or all of the acrylate in the molecule of the above compound is used can be used.

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.

On the other hand, as an example of an oligomer or polymer having a functional group in the molecule, a functional group may be added to a side chain or a molecular terminal of an oligomer or polymer obtained by polymerizing at least one of the above-mentioned monomers. Can be used. Including at least alkyl acrylate or alkyl methacrylate, more preferably,
By containing at least methyl methacrylate, a polymer having good thermal decomposability can be obtained.

Preferred functional 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.

The method of adding such a functional group to an oligomer or a polymer is based on 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 ether crotonic acid, glycidyl ether isocrotonic acid, and the like. .

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 from 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.

Further, by copolymerizing an unsaturated acid such as an unsaturated carboxylic acid, the developability after exposure can be improved. 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 polymer or oligomer having an acidic group such as a carboxyl group in the side chain thus obtained has an acid value (AV) of 50 to 150, preferably 50 to 120. 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.

Further, as a binder, non-photosensitive to polyvinyl alcohol, polyvinyl butyral, methacrylate polymer, acrylate polymer, acrylate-methacrylate copolymer, α-methylstyrene polymer, butyl methacrylate resin, etc. A hydrophilic polymer may be added.

It is preferable to use the photosensitive monomer in an amount of 0.05 to 10 times the amount of the oligomer or the polymer. More preferably, the amount is 0.1 to 3 times. If the amount exceeds 10 times, the viscosity of the paste becomes small, and the dispersibility in the paste may be reduced. If the amount is less than 0.05 times, the solubility of the unexposed portion in the developer tends to be poor.

In the present invention, a glass frit can be contained in the electrode. This is because glass frit has an effect of baking conductive powder on a glass substrate, a sintering aid for sintering the conductive powder, and an effect of reducing conductor resistance. Glass transition temperature of glass frit (Tg)
And the glass softening point (Ts) is 400 to 50, respectively.
The temperature is preferably 0 ° C and 450 to 550 ° C. Preferably, Tg and Ts are 440 to 500 ° C. and 46, respectively.
0-530 ° C. Tg and Ts are each 400 ° C.
If the temperature is lower than 450 ° C., the sintering of the glass starts before the photosensitive organic compound such as a polymer or a monomer evaporates, the binder removal of the organic compound does not work well, and carbon remains after firing, which causes the electrode to peel off, and is dense and dense. It is not preferable because a conductor film having low resistance cannot be obtained. If Tg and Ts exceed 500 ° C. and 550 ° C., respectively, the glass frit cannot obtain a sufficient adhesive strength or a dense film between the conductive film and the glass substrate when baked at a temperature of 600 ° C. or less.

The powder particle size of the glass frit is such that the average particle size (D50) is 0.5 to 1.4 μm and the 10% particle size (D50)
10) is preferably 0.3 to 0.6, the 90% particle diameter (D90) is 0.7 to 2 μm, and the maximum size is 4.5 μm or less. More preferably, D50 is 0.5 to
1, D10 is 0.3-0.5, D90 is 0.7-1.
5. The top size is 2 μm or less. D50, D1
0, D90% particle size is 0.5, 0.3, 0.7 respectively
If it is less than μm, the particle size of the glass frit becomes too small, and the ultraviolet light is scattered to the unexposed portion, photocuring occurs at the edge and end of the electrode, and the electrode cannot be completely developed.
Therefore, the cut / resolution of the electrode pattern is reduced.
If the D50, D10, and D90% particle diameters and the top size exceed 1.4, 0.6, and 2,4.5 μm, respectively, short defects will occur if coarse glass frit remains between the electrodes.

The coefficient of thermal expansion α ₅₀ to _{400 at 50} to ₄₀₀ ° C. of the glass frit is preferably 75 to 90 × 10 ⁻⁷ / ° K. If α is not in this range, the conductor film baked on the glass substrate will be peeled off during cooling due to the difference in α between the substrate and the glass frit.

In the present invention, the composition of the glass frit is preferably such that Bi ₂ O ₃ is contained in the range of 30 to 95% by weight. When the amount is less than 30% by weight, when the conductive paste is baked on a glass substrate, the glass transition point and the softening point are not sufficiently controlled, and the effect of increasing the adhesive strength of the conductive film to the substrate is small. If it exceeds 95% by weight, the softening point of the glass frit becomes too low, and the glass frit is melted before the binder in the paste evaporates. For this reason, the binder removal property of the paste is deteriorated, the sinterability of the conductor film is reduced, and the adhesive strength with the substrate is reduced.

Further, the glass frit has a composition range of 30 to 95 parts by weight of Bi ₂ O _3, 5 to 30 parts by weight of SiO _2, 6 to 20 parts by weight of B ₂ O _{3 and 2 to} 20 parts by weight of ZnO in terms of oxide. It is preferable that the content is 80% by weight or more. Within this range, a glass frit that can firmly bake a conductive film on a glass substrate at 550 to 600 ° C. is obtained.

In particular, when the glass frit composition of the present invention is used, PbO which is liable to cause a gelling reaction of a photosensitive organic component is obtained.
It is possible to obtain a preferable glass frit without using any of the above methods, to avoid a problem that a paste viscosity is increased due to a gelling reaction and a problem that a pattern cannot be formed, and to obtain a stable conductive paste.

The content of SiO ₂ is preferably in the range of 5 to 30% by weight, and if it is less than 5% by weight, the adhesive strength when baked on the substrate and the stability of the glass frit are reduced. On the other hand, if it exceeds 30% by weight, the heat-resistant temperature increases, and it becomes difficult to bake on a glass substrate at 600 ° C or lower.

It is preferable that B ₂ O ₃ is blended in the range of 6 to 20% by weight. B ₂ O ₃ has a baking temperature of 550 to 550 so as not to impair the electrical, mechanical and thermal properties of the conductive paste, such as electrical insulation, adhesive strength, and thermal expansion coefficient.
It is blended to control in the range of 600 ° C. 6% by weight
If the amount is less than the above, the adhesion strength is reduced, and if it exceeds 20% by weight, the stability of the glass frit is reduced.

It is preferable that ZnO is blended in the range of 2 to 20% by weight. When the amount is less than 2% by weight, the effect of controlling the baking temperature when baking the conductive paste on the glass substrate is small. If it exceeds 20% by weight, the heat-resistant temperature of the glass will be too low, and it will be difficult to bake it on a glass substrate.

The glass frit powder includes Na ₂ O, Li ₂ O, K ₂ O, BaO, and CaO, which react with silver powder to cause yellowing of the glass substrate and deteriorate plasma discharge characteristics.
It is preferred that they do not substantially contain an alkali metal or alkaline earth metal oxide. Substantially not included
It is at most 0.5% by weight, preferably at most 0.1% by weight.

Further, Al ₂ O ₃ , B
The thermal expansion coefficient, glass transition point, and glass softening point can be controlled by adding aO, TiO ₂ , ZrO _2, etc., but the amount is preferably less than 10% by weight.

The content of glass frit in the photosensitive conductive paste is preferably 1 to 4% by weight. More preferably, it is 1 to 3.5% by weight. It is preferable that the amount of the glass frit is low in order to reduce the resistance and the thickness of the electrodes of the front panel and the rear panel of the PDP. Since the glass frit is electrically insulating, if the content exceeds 4% by weight, the resistance of the electrode increases, which is not preferable. Further, when the glass frit increases, in a thin film conductor of 10 μm or less, film peeling occurs due to a difference in thermal expansion coefficient between the conductive powder and the glass frit. If it is less than 1% by weight, it is difficult to obtain a strong adhesive strength between the electrode film and the glass substrate.

In the photosensitive conductive paste used for the electrode used in the present invention, if necessary, a photopolymerization initiator, a sensitizer, a sensitization aid, a polymerization inhibitor, a plasticizer, a thickener, Additive components such as organic solvents, antioxidants, dispersants, and organic or inorganic suspending agents can be added.

Specific examples of the photopolymerization initiator used in the present invention include benzophenone, methyl o-benzoylbenzoate, 4,4-bis (dimethylamine) benzophenone, 4,4-bis (diethylamino) benzophenone, α-amino acetophenone, 4,4-dichlorobenzophenone, 4-benzoyl-4-methyldiphenylketone, dibenzylketone, fluorenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenyl-2-phenyl Acetophenone, 2-hydroxy-2-methylpropiophenone, pt-butyldichloroacetophenone, thioxanthone, 2-methylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, diethylthioxanthone, benzyl, benzyldimethyl Ketanoru, benzyl - methoxyethyl acetal, benzoin, benzoin methyl ether, benzoin butyl ether, anthraquinone, 2
-T-butylanthraquinone, 2-amylanthraquinone, β-chloranthraquinone, 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,
Combinations of photoreducing dyes such as benzothiazole disulfide, triphenylphosphine, camphorquinone, carbon tetrabromide, tribromophenylsulfone, benzoin peroxide and eosin, and methylene blue with reducing agents such as ascorbic acid and triethanolamine. No. In the present invention, one or more of these can be used.

Further, the photopolymerization initiator is usually used in an amount of 0.1 to 30% by weight, more preferably, to the photosensitive organic component.
Use 2 to 20% by weight. If the amount of the photopolymerization 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.

In the present invention, it is preferable to add an ultraviolet light absorber composed of an organic dye for forming an electrode pattern. By adding a light absorbing agent having a high ultraviolet absorbing effect, a line width of 10 at an electrode thickness of 5 to 15 μm after baking is obtained.
A high-resolution pattern with a thickness of ４０40 μm and a line spacing of 10-40 μm between electrodes can be formed. Further, the electrode cross section becomes rectangular, the pattern end is excellently cut, and an electrode pattern free from bleeding and edge curl can be obtained.

That is, usually, when the conductive powder alone is used, ultraviolet rays are scattered by the conductive powder having a size of 1 μm or less or the agglomerated conductive powder having a non-uniform shape, and are light-cured to an excessive part.
The pattern as the exposure mask cannot be obtained. For this reason, the portion other than the mask cannot be developed. The present inventors have conducted intensive studies on the cause, and as a result, it has been found that the scattered ultraviolet light is absorbed or weakened and reaches the light-shielded portion by the exposure mask. Therefore, the ratio of the straight light increases by adding the ultraviolet light absorber, the wraparound of the scattered light is almost avoided, the hardening of the photosensitive resin of the mask portion is prevented,
A pattern corresponding to the exposure mask is formed.

Further, the photosensitive conductive paste used for the electrode of the present invention has a paste composition design having a high total light transmittance in the g-line (wavelength: 436 nm) region.
It is preferable that the ultraviolet absorber absorbs light only in the g-line region by cutting light on the longer wavelength side and lower wavelength side than the g-ray, so that the function can be provided.

As the ultraviolet absorbent, those composed of organic dyes are used. Among them, organic dyes having a high UV absorption coefficient in the wavelength range of 350 to 450 nm are preferably used. Azo dyes, amino ketone dyes as organic dyes,
Xanthene dyes, quinoline dyes, aminoketone dyes, anthraquinone dyes, benzophenone dyes, diphenylcyanoacrylate dyes, triazine dyes, 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 conductor film characteristics due to the light absorbing agent can be reduced without remaining in the electrode conductor film after firing. Among them, azo dyes and benzophenone dyes are preferable because they have a function as a filter capable of cutting light having a wavelength longer than the g-line.

As representative azo dyes,
Sudan Blue _{(Sudan Blue, C 22 H 18} N 2 O
₂ = 342.4), Sudan R (C ₁₇ H ₁₄ N ₂ O ₂ = 27
8.31), Sudan _{II (C 18 H 14 N 2} O = 276.3
4), Sudan _{III (C 22 H 16 N 4} 0 = 352.4), Sudan _{IV (C 24 H 20 N 4} 0 = 380.45), Oil Orange _{SS (Oil Orange SS, CH 3} C 6 H
_{4 N: NC 10 H 6 OH} = 262.31) Oil Violet _{(Oil Violet, C 24 H 21} N 5 = 379.
46), Oil Yellow OB (Oil Yellow)
_{OB, CH 3 C 4 H 4} N: NC 10 H 4 NH 2 = 261.
33).

As benzophenone dyes, Ubinal D-50 (C ₁₃ H ₁₀ O ₅ = 246.22, 2,2 ′,
4,4-tetrahydro-oxy benzophenone), Uvinul _{MS40 (C 14 H 12 O 6} S = 308,2- hydroxy-4-methoxybenzophenone 5-sulfonic acid), Uvinul _{DS49 (C 15 H 12 O 11} S 2 Na 2 =
478,2,2-dihydroxy-4,4'-dimethoxybenzophenone 5,5'-sodium disulfonate)
However, a dye capable of absorbing light at 250 to 520 nm can be used.

The amount of the organic dye added is from 0.01 to 0.5
% By weight is preferred. More preferably 0.01 to 0.1
% By weight. If the amount is less than 0.01% by weight, the effect of addition is low, and the effect of eliminating cuts or bleeding of the pattern and curling of the edge portion is small. If it exceeds 0.5% by weight, the effect of absorbing ultraviolet light becomes too large, and photocuring is performed until light reaches the lower portion of the conductive film, so that the film is easily peeled off during development, or a high-definition pattern cannot be formed.

A preferred example of the method of adding the ultraviolet light absorber is as follows. A solution is prepared by dissolving an ultraviolet absorber in an organic solvent in advance. Next, after mixing the conductive powder in the organic solvent, the mixture is dried. By this method, a so-called capsule-like powder in which the surface of each of the conductor powders is uniformly coated with an organic dye film can be produced.

In the present invention, there is a preferable range of integrated value of absorbance (wavelength measurement range; 350 to 450 nm).
The integrated value of the absorbance is measured in a powder state, and is measured for a powder coated with an organic dye.

In the present invention, the absorbance is defined as follows. That is, light is applied to the measurement sample in an integrating sphere using a commercially available spectrophotometer, and the light reflected there is collected and detected. In addition, all the light except for the light detected by the integrating sphere is regarded as absorption light and can be obtained from the following equation.

Before measuring the absorbance of the sample, Ir was used to measure the light intensity of the control light by measuring the light intensity by reflection by attaching BaSO ₃ of the same material as the material coated on the inner surface of the integrating sphere to the sample table before measuring the absorbance of the sample. Data), the light intensity of the light incident on the sample is I, and the light intensity of the absorption after irradiating the sample is Io, and the light intensity of the reflection from the sample is represented by (I-Io). Is defined as in the following equation (1). In the above, the unit of the light intensity is represented by W / cm ² .

Absorbance = −log ((I−Io) / Ir) (1) The absorbance is measured as follows.

First, the powder to which the light absorbing agent has been added is molded into a size of 20 mm in diameter and 4 mm in thickness by a press. Next, using a spectrophotometer, a powder molded body was attached to the mounting hole of the reflecting sample of the integrating sphere, and the absorbance due to the reflected light was measured in a wavelength range of 20 nm.
When measured at 0 to 650 nm, a graph as shown in FIG. 1 is obtained. The vertical axis indicates the absorbance of equation (1), and the horizontal axis indicates the measurement wavelength. Next, the area of a section having a wavelength of 350 to 450 nm was determined in FIG. 1, and the area S was defined as an integrated value of absorbance at a wavelength of 350 to 450 nm.

In the present invention, the preferable range of the integrated value of the absorbance is 30 to 60, more preferably 35 to 60.
~ 50. If the absorbance is less than 30, light is scattered by the conductive powder before sufficiently transmitting to the lower part of the conductive film during ultraviolet exposure, and the unexposed portion is hardened, so that a high-resolution pattern cannot be formed. If the absorbance exceeds 60, the light is absorbed by the conductive powder before reaching the lower portion of the conductive film, and the light cannot be cured because the light does not transmit to the lower conductive film. As a result, they come off during development, making it difficult to form electrodes.

In the present invention, when a metal and / or metal oxide serving as a sintering aid is added in addition to the glass frit, the conductive powder can avoid abnormal grain growth during sintering, or can delay sintering. It is preferable because it works effectively as a so-called sintering aid. As a result, the adhesive strength between the conductor film and the glass substrate is increased, which is preferable. As such an oxide powder, a metal such as Cu, Cr, Mo, Al or Ni and / or a metal oxide can be used. Of these, metal oxides function electrically as insulators, so the amount of the additive is preferably small, and is preferably 3% by weight or less. If it exceeds 3% by weight, the electric resistance of the conductor film increases, which is not good. It is also preferable to use a metal oxide and a metal together.

A sensitizer is added to improve the sensitivity. Specific examples of the sensitizer include 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, dimethylamino Isoamyl benzoate, isoamyl diethylaminobenzoate, 3-phenyl-5-benzoylthio-tetrazole, 1-phenyl-5-ethoxycarbonylthio-tetrazole and the like can be mentioned. 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 conductive paste of the present invention, the amount of the sensitizer to be added is usually 0.1 to 10% based on the amount of the reactive component.
It is 10% by weight, more preferably 0.2 to 5% by weight.
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.

In order to improve the thermal stability during storage in the conductive paste of the electrode of the present invention, it is preferable to add a thermal polymerization inhibitor. Specific examples of the thermal polymerization inhibitor include hydroquinone, N-nitrosodiphenylamine, phenothiazine, pt-butylcatechol, N-phenylnaphthylamine, 2,6-di-t-butyl-p-methylphenol, chloranil, Pyrogallol and the like.
When a thermal polymerization inhibitor is added, the amount thereof is usually 0.1 to 5% by weight, more preferably 0.2 to 3% by weight, in the photosensitive conductive paste. If the amount of the thermal polymerization inhibitor is too small, the effect of improving the thermal stability during storage is not exhibited, and if the amount of the thermal polymerization inhibitor is too large, the residual ratio of the exposed portion may be too small. is there.

As the plasticizer, for example, dibutyl phthalate (DBP), dioctyl phthalate (DOP), polyethylene glycol, glycerin and the like are used.

Further, an antioxidant can be added to the conductive paste of the electrode of the present invention in order 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, and 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 an antioxidant is added, its amount is usually 0.01 to 5% by weight, more preferably 0.1 to 1% by weight, in the photosensitive conductive paste. If the amount of the antioxidant is small, the effect of preventing oxidation of the acrylic copolymer during storage cannot be obtained, and if the amount of the antioxidant is too large, the residual ratio of the exposed portion may be too small.

When the viscosity of the solution is to be adjusted, an organic solvent may be added to the photosensitive conductive paste used for the electrode of the present invention. As the organic solvent used at this time, methyl cellosolve, ethyl cellosolve, butyl cellosolve,
Methyl ethyl ketone, dioxane, acetone, cyclohexanone, cyclopentanone, isobutyl alcohol,
Isopropyl alcohol, tetrahydrofuran, dimethyl sulfoxide, γ-butyrolactone and the like. These organic solvents are used alone or in combination of two or more.

The preferred composition of the photosensitive conductive paste is preferably selected in the following range.

(A) conductive powder; (a)
(B) 84 to 94% by weight based on the sum of (c) (b) a photosensitive polymer and a photosensitive monomer;
15 to 5% by weight based on the sum of (b) and (c) (c) Glass frit; 1 to 4% by weight based on the sum of (a), (b) and (c) (d) Photopolymerization initiation 5% to 20% by weight with respect to (b) (e) UV absorber; 0.01 to 10% with respect to (a)
0.5% by weight In the above, more preferably, (a), (b), (c)
Are 86 to 92% by weight, 11 to 7% by weight, and 1 to 3% by weight, respectively. Within this range, ultraviolet rays are well transmitted at the time of exposure, the photocuring function is sufficiently exhibited, the film strength of the exposed portion at the time of development is increased, and an electrode pattern having a fine resolution can be formed. The fired conductor film is preferable because it has low resistance and high adhesive strength.

If necessary, a sensitizer, a photopolymerization accelerator, a plasticizer, a dispersant, a stabilizer, a thixotropic agent, and an organic or inorganic suspending agent are added to form a mixture slurry. The slurry adjusted to have a predetermined composition is uniformly mixed with a stirrer such as a homogenizer, and then uniformly dispersed with a three-roller or kneader to produce a paste.

The viscosity of the paste is determined by using a conductive powder, an organic solvent,
It is appropriately adjusted depending on the composition and type of the glass frit, the addition ratio of the plasticizer, the thixotropic agent, the suspending agent, the organic leveling agent, and the like. The range is 10,000 to 150,000 cps (centipoise) at 3 rpm. is there.
For example, 50,000 to 100,000 cps is preferable for obtaining a film thickness of 10 to 20 μm by coating the glass substrate with a screen printing method, a bar coater, a roller coater, or an applicator once or twice to obtain a film thickness of 10 to 20 μm.

The method of forming the electrode of the present invention includes screen printing, vacuum evaporation, sputtering and the like. In this case, the PD is formed by photolithography using a photosensitive conductive paste.
A method for forming a P electrode pattern and the like will be described.

That is, the PD used for the electrode of the present invention
The photosensitive conductive paste for P is usually applied on a glass substrate by a screen printing method. Print thickness is 250 to 32 for screen material (polyester or stainless steel)
It can be arbitrarily controlled by adjusting a 5-mesh screen, screen tension, and paste viscosity.
１５15 μm. A more preferable thickness range is 3 to
10 μm. When the thickness is less than 3 μm, it becomes difficult to obtain a uniform thickness by the printing method. On the other hand, if it exceeds 15 μm, the accuracy of the electrode pattern decreases, the cross-sectional shape becomes an inverted trapezoid, and a high-definition pattern with a minimum line width / minimum width interval of 30 μm / 30 μm or less and edge cut off deteriorate.

When the photosensitive conductive paste is applied on a glass substrate, it is preferable to perform a surface treatment on the substrate in order to enhance the adhesion between the substrate and the coating film. As the surface treatment liquid, a silane coupling agent such as vinyltrichlorosilane,
Vinyltrimethoxysilane, vinyltriethoxysilane, tris- (2-methoxyethoxy) vinylsilane,
γ-glycidoxypropyltrimethoxysilane, γ-
(Methacryloxypropyl) trimethoxysilane, γ
(2-aminoethyl) aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, or the like, or an organic metal such as organic titanium, organic aluminum, or organic zirconium. is there. A silane coupling agent or an organic metal diluted with an organic solvent such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl alcohol, ethyl alcohol, propyl alcohol, and butyl alcohol to a concentration of 0.1 to 5% is used.
Next, the surface treatment liquid is uniformly applied on a substrate by a spinner or the like, and then dried at 80 to 140 ° C. for 10 to 60 minutes to perform surface treatment.

Next, the film obtained by applying such a photosensitive conductive paste on a substrate is dried by heating at 70 to 120 ° C. for 20 to 60 minutes to evaporate the solvent, and then the electrode pattern is formed by photolithography. The photosensitive paste is photocured by irradiating it with ultraviolet light using a film or a mask such as a chrome mask. Examples of the active light source used in this case include ultraviolet rays, electron beams, and X-rays. Among them, ultraviolet rays are preferable, and examples of the light source include low-pressure mercury lamps, high-pressure mercury lamps, halogen lamps, and germicidal lamps. it can. Among these, an ultra-high pressure mercury lamp is preferred. Exposure conditions vary depending on the thickness of the conductive film, but it is preferable to perform exposure for 1 to 30 minutes using an ultrahigh pressure mercury lamp having an output of 5 to 100 mW / cm ² .

Next, a part which is not cured by the exposure is removed by using a developing solution to form an electrode pattern (a so-called negative type). The development is performed by an immersion method or a spray method. As the developer, an organic solvent in which the mixture of the photosensitive organic components 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 reactive component having a carboxyl group is present, development can be performed with an aqueous alkali solution. As the alkali aqueous solution, a metal alkali aqueous solution such as sodium hydroxide, sodium carbonate, calcium hydroxide aqueous solution or the like can be used. However, it is preferable to use an organic alkali aqueous solution since the alkali component can be easily removed at the time of firing. Specific examples of the organic alkali include tetramethylammonium hydroxide, trimethylbenzylammonium hydroxide, monoethanolamine, diethanolamine and the like. The concentration of the aqueous alkali solution is usually 0.05 to 0.5% by weight, more preferably 0.1 to 0.5% by weight. If the concentration of the aqueous alkali solution is less than 0.05% by weight, the dissolving power is reduced, unexposed portions are not removed, and if it exceeds 0.5% by weight, the exposed portions may be corroded.

Next, the coating film after exposure and development is fired in air. Reactive components and binders such as photosensitive polymers and photosensitive monomers that are photosensitive organic components, photopolymerization initiators, ultraviolet light absorbers, sensitizers, sensitization aids, plasticizers, thickeners, organic solvents, and dispersion Additives such as agents or organic substances such as solvents are completely oxidized and evaporated. 560-610 ° C
For 15 minutes to 1 hour, and baking on a glass substrate. If the temperature is lower than 560 ° C., the sintering is insufficient, so that the denseness of the conductor film is reduced, the specific resistance is increased, and the bonding strength with the substrate is undesirably reduced. 610 ° C
Exceeding the limit causes the glass substrate to be thermally deformed and the flatness of the pattern to be reduced.

The preparation, printing, exposure and development steps of the photosensitive conductive paste for PDP used in the electrode of the present invention need to be performed in a place where ultraviolet rays can be blocked. Otherwise, the paste or coating film will be photo-cured by ultraviolet rays, and a conductor film that can exhibit the effects of the present invention cannot be obtained.

When the electrode pattern is formed using the photosensitive conductive paste used for the electrode of the present invention, for example, when the thickness of the conductor film after firing is 4 to 15 μm, the minimum line width of the conductor is 20 μm, and the maximum distance between the conductors is 20 μm. A narrow interval of 20 μm is obtained.

[0085]

The present invention will be described in detail with reference to the following examples. Electrodes were formed and evaluated according to the following materials A to H and a to f in the following order. In the following examples, all concentrations are expressed by weight% unless otherwise specified.

Examples 1 to 14 The particle size distribution (average particle size, specific surface area, etc.) of the conductive powder and the glass frit was measured using a Microtrac particle size analyzer (9320-HRA) manufactured by Leed & Northrup.

A. Conductive powder (1) Ag powder; monodisperse granular, average particle diameter 3.0 μm, specific surface area 0.48 m ² / g, tap density 4.74 g / cm ³ (2) 98% Ag-2% Pd powder; B. Dispersed granular, average particle size 3.3 μm, specific surface area 0.82 m ² / g Photosensitive polymer (hereinafter abbreviated as polymer) A copolymer composed of 40 mol% of methacrylic acid (MAA), 30 mol% of methyl methacrylate (MMA) and 30 mol% of styrene (St) has a content of 0.1% based on MAA. Polymer obtained by addition reaction of 4 equivalents of glycidyl methacrylate (GMA) D. Photosensitive monomer (hereinafter abbreviated as monomer) Trimethylolpropane triacrylate Glass frit component (% by weight) bismuth oxide (46.2), silicon dioxide (27.1), boron oxide (11.8), zinc oxide (2.
6), sodium oxide (4.7), aluminum oxide (2.8), zirconium oxide (4.8), glass transition point: 461 ° C, glass softening point: 513 ° C, 50 to 400
C. Thermal expansion coefficient (α) 50 to 400; 82 × 10 ⁻⁷ / ΔKE Solvent γ-butyrolactone F. Photopolymerization initiator 2-methyl-1- [4- (methylthio) phenyl] -2
Morpholino-1-propanone and 2,4-diethylthioxanthone are added to the sum of
0% was added.

G. Plasticizer Dibutyl phthalate (DBP) was added at 10% of the polymer.

H. SiO ₂ dissolved in the thickener 2- (2-butoxyethoxy) ethyl acetate (concentration 15%) was added 4% relative to the polymer.

A. Preparation of Organic Vehicle The solvent and the polymer were mixed and heated to 60 ° C. with stirring to dissolve all the polymers homogeneously. Then the solution is cooled to room temperature.

B. Paste preparation The conductive powder, glass frit, monomer, photopolymerization initiator, plasticizer, thickener and solvent are added to the above organic vehicle so as to have a predetermined composition, and mixed and dispersed with three rollers to paste. Was prepared. Table 1 and Table 2 show the composition of the paste.
Shown in

C. Printing The above paste was put on a glass substrate (120 mm square, 1.2 mm thick) using a 325 mesh screen.
It was printed solid on a square mm and dried at 80 ° C. for 40 minutes. The coating thickness after drying varies depending on the structure, but was 12 to 15 μm.

D. Exposure and development Using a chromium mask on which a plasma display panel electrode having a fine pattern of 40 to 70 μm was formed, the coating film prepared above was exposed to ultraviolet light from an upper surface for 60 seconds with an ultra-high pressure mercury lamp having an output of 15 mW / cm ² . . Then 2
The film was immersed in a 0.1% by weight aqueous solution of monoethanolamine kept at 5 ° C. for development, and then unexposed portions were washed with water using a spray.

E. Firing The coating film printed on the glass substrate is heated in air at a heating rate of 250
Heating was performed at a temperature of 600 ° C./hour, and calcination was performed at a temperature of 600 ° C. for 15 minutes, thereby producing an electrode conductor film.

F. Evaluation The number of short defects was counted for the fired electrode. In addition, a plasma display was manufactured using this electrode substrate, and the image display characteristics were evaluated. The resulting image was clear and excellent display without defects was achieved.

Comparative Examples 1-3 Pastes were prepared under the same conditions as in the above Examples except that Ag powder (1) was used in the above Examples and that the glass frit had a different particle size distribution as shown in Table 3. Was prepared.

The number of short defects was counted for the fired electrode in the same manner as in the example. An attempt was made to repair (repair) these electrode defects, but the number was large and the defects could not be eliminated. In addition, when a plasma display was manufactured using the manufactured electrode substrate, and the image display characteristics were evaluated, the obtained image had many missing pixels and became very hard to see. Further, when the light was continuously turned on, the defect portion tended to spread and expand, and the discharge voltage gradually increased.

[0098]

[Table 1]

[Table 2]

[Table 3]

[0099]

According to the present invention, a clear and high-quality image can be obtained by using a high-definition electrode panel having a fine pattern without a short-circuit defect in a plasma display.

Claims (7)

[Claims] 1. A plasma display having electrodes formed on a substrate, wherein the electrodes have a thickness of 1 to 10 μm, a line width of 20 to 200 μm, and have five or less short defects. Plasma display. 2. The plasma display according to claim 1, wherein there are no short defects over three or more electrodes per substrate, and the total number of short defects over two or less electrodes is two or less. 3. The length per electrode is 200 mm to 20 mm.
00 mm and the number of electrodes per substrate is 1200 to 1
3. The plasma display according to claim 1, wherein the number is 0000. 4. The plasma display according to claim 1, wherein the electrodes are formed by applying a photosensitive conductive paste on a substrate, forming a pattern by photolithography, and then firing. 5. A method according to claim 1, wherein a photosensitive conductive paste containing a conductive powder, glass frit, and a photosensitive organic component is applied onto a substrate, patterned by photolithography, and fired. The manufacturing method of the plasma display according to the above. 6. The glass frit having an average particle size of 0.5 to 0.5.
The method for manufacturing a plasma display according to claim 5, wherein the particle size is 1.4 µm, the 90% particle size is 1 to 2 µm, and the top size is 4.5 µm or less. 7. The method according to claim 5, wherein the conductive powder contains at least one selected from the group consisting of Ag, Au, Pd, Ni and Pt.