JPH10194778A - Electroconductive baked material and gas discharge indication panel using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroconductive baked material suitable for a method advantageous for forming an electrode for a gas discharge indication panel having a fine structure and resolvable for a problem of color tone by using silver powder as electroconductive powder, an electrode composed of the electroconductive baked material and a gas discharge indication panel using the electrode as a bath electrode or an anode. SOLUTION: This electroconductive baked material is obtained by using an electroconductive composition containing (A) 100 pts.wt. of silver powder, (B) 0.1-30 pts.wt. of glass powder and (C) 0.5-20 pts.wt. of black inorganic powder and having photosensitivity, forming a pattern by photolithography and baking. The alternating current-type gas discharge indication panel uses the electroconductive baked material as a bath electrode and the direct current-type gas discharge indication panel uses the electroconductive baked material as an anode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive fired body for a gas discharge display panel (plasma display panel, PDP), and more particularly to a fired body having a low electric resistance.
The present invention relates to a conductive fired body having good color contrast. The present invention also relates to an electrode made of the conductive fired body, an AC gas discharge display panel using the electrode as a bus electrode, and a DC gas discharge display panel also using the electrode as an anode.

[0002]

2. Description of the Related Art AC and DC gas discharge display panels are known. For example, a typical basic structure of an AC type gas discharge display panel is as shown in FIG. FIG. 1 is a perspective view showing the inside of the panel, in which the panel is cut away to show the main part of the basic structure.

According to this structure, the display surface side substrate 1 and the back side substrate 2 made of a translucent material such as glass are configured to face each other with a predetermined space. Has a structure in which a rare gas is sealed as a discharge gas.

[0004] The display surface side substrate 1 is provided with a large number of discharge sustaining electrode pairs comprising a pair of parallel sustaining electrodes extending in the horizontal direction and composed of a transparent electrode 3 and a bus electrode 4. Are covered with a transparent dielectric layer 5 and a transparent protective layer 6. Similarly, a large number of address electrodes 8 are provided on the rear substrate 2 covered with the dielectric layer 7 so as to be orthogonal to the discharge sustaining electrode pairs. A discharge cell is defined by a partition wall 9 at or near the intersection between the pair of discharge sustaining electrodes and the address electrode 8, and the discharge cells are selectively discharged to cause the phosphors 10 to emit light. Is performed.

As a method of forming a discharge sustaining electrode, a transparent electrode 3 is formed, for example, by applying an IT over the entire surface of a display surface side glass substrate 1.
By forming an O (indium-tin oxide) film or a nesa (tin oxide) film in advance by a method such as a CVD method or a sputtering method, and then performing an etching process by photolithography, a desired electrode pattern is formed. It is formed.

The bus electrode 5 is formed by applying a photoresist to the entire surface of the glass substrate on the display surface side after forming the transparent electrode,
A bus electrode having a desired pattern can be obtained by forming a metal thin film of, for example, gold over the entire surface by a method such as vacuum deposition, excluding the bus electrode forming portion by exposure and phenomenon, and then removing the photoresist. Or,
It is obtained by forming a pattern by screen printing a paste containing a conductive metal powder such as silver, gold, or aluminum, and then performing baking.

[0007] The use of such screen printing has the advantage that the process is simpler and the loss of material is smaller than in photolithography, but it is difficult to obtain a highly accurate pattern shape. Therefore, it is generally preferable to use photolithography for applications requiring a highly accurate pattern shape such as a high-definition gas discharge display panel.

[0008] As a transparent substrate, a glass substrate is most common. As a method of forming electrodes and wiring on a glass substrate, various methods as described above can be mentioned, but since electric resistance is low and pattern accuracy is high, a pattern is formed by photolithography using silver. The method is general.

However, when silver is used, the interface between the silver and the glass substrate becomes silver or ocher by baking after forming the pattern. The silver color is the color of the thick film itself obtained by sintering silver powder with a binder such as glass powder, and the ocher color is silver powder, glass powder as a binder, and a float method. This is the color produced by the reaction of tin existing on the bottom surface of a glass substrate when the substrate is manufactured.

When the glass substrate on which the sustain electrodes including the bus electrodes are formed as described above is used as a display surface side substrate of a gas discharge display panel, the display quality of colors is greatly affected. That is, when the bus electrode exhibits a silver color, it reflects external light, so that the contrast of the display decreases. When the bus electrode exhibits an ocher color, the color tone of the color display deviates from the original color tone, and the entire display screen is displayed. It looks yellowish.

As an example of the countermeasure, there has been proposed a method of interposing a black paste film at an interface between a thick silver film and a glass substrate (Japanese Patent Application Laid-Open No. 6-12987). However, in such a method, although the display contrast is enhanced, the steps are complicated and the manufacturing cost is increased.

On the other hand, when gold or silver-palladium is used as the conductive metal powder, not only the electrical resistance is higher than silver, but also the material cost is greatly increased. Further, the use of aluminum, nickel, or the like is not preferable because the resistance is significantly higher than that of silver.

Although the resistance is reduced when copper is used, in the case of a gas discharge display panel, a copper bus electrode formed by a method such as an electron beam evaporation method or a sputtering method forms the next inductive layer or partition. Since the process requires an oxidizing atmosphere, it is oxidized to copper oxide in the process. Therefore, in order to protect the copper electrode from oxidation, it is necessary to further form a barrier layer before proceeding to the next step. In addition, since the copper electrode has a copper color, the color tone of the display screen is shifted as in the case of using silver, and as a countermeasure, it is necessary to form a bus electrode by overlaying a black material such as chrome as a base. There is. As described above, when copper is used, a bus electrode composed of multiple layers is formed, so that the process becomes very complicated and the manufacturing cost increases.

Although the above is an example of the formation of the bus electrode in the AC type gas discharge display panel, the same can be said for the formation of the anode in the DC type gas discharge display panel.

Considering that the electric resistance is low and the pattern precision is high, the most desirable method for forming these electrodes is to form a pattern by photolithography using silver. In particular, since the screen size of a gas discharge display panel is further increased in the future, it is necessary to further reduce the resistance of electrodes and wiring. Furthermore, in order to replace conventional CRTs and projection TVs not only for industrial use but also for consumer use, low manufacturing costs are extremely important requirements.

[0016]

SUMMARY OF THE INVENTION It is an object of the present invention to use a silver powder as a conductive powder and to form a so-called high-definition gas discharge display panel electrode having a particularly fine structure among gas discharge panels. An object of the present invention is to provide a conductive fired body which is suitable for a method and which solves the above-mentioned color tone problem. Another object of the present invention is to provide an AC gas discharge display panel using such a conductive fired body as a bus electrode,
And a DC gas discharge display panel used as an anode.

[0017]

Means for Solving the Problems As a result of repeated studies to solve the above problems, the present inventor has found that in addition to silver powder and glass powder, a specific amount of inorganic fine powder exhibiting black color is used as an electrode. By using a conductive fired body obtained by forming a pattern by photolithography and then firing the composition obtained by blending, it has been found that the problem can be solved, and the present invention has been achieved. Was.

That is, the present invention comprises (A) 100 parts by weight of silver powder; (B) 0.1 to 30 parts by weight of glass powder; and (C) 0.5 to 20 parts by weight of a black inorganic powder. A conductive fired body obtained by forming a pattern by photolithography using a photosensitive composition and then firing the same; further, an electrode made of the conductive fired body; and a pair of electrodes facing each other across a discharge space. Substrate, provided on at least one inner surface of the substrate, a discharge sustaining electrode comprising a transparent electrode and a bus electrode, and an AC type gas discharge display comprising a dielectric layer and a protective layer sequentially provided inside the discharge sustaining electrode. Panel; or a direct current gas discharge display panel having a pair of substrates opposed to each other across a discharge space, an anode provided on the inner surface of one substrate, and a cathode provided on the inner surface of the other substrate. The present invention relates to a gas discharge display panel, wherein a bus electrode or an anode is an electrode made of the above-mentioned conductive fired body.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The silver powder of the component (A) used in the conductive fired body of the present invention imparts conductivity to the fired body and may be spherical or flaky. In the case where a pattern having a line width of about 50 μm is formed, a spherical one is preferable in consideration of the ease of development and the low resistance of the gas discharge display panel compatible with HDTV. The particle size is usually 0.05-5 μm,
0.2 to 3 μm is preferred. When the thickness is less than 0.05 μm, a conductor having a low electric resistance can be obtained, but light is difficult to pass through due to a large hiding power of the coating film, and development is difficult. On the other hand, 5μ
If m is exceeded, development is easy but sinterability deteriorates,
Electric resistance increases.

The glass powder of the component (B) is a binder for binding the components (A) to each other, and further enhances the adhesion of the conductive fired body to the substrate and softens during sintering. ,
There is an effect that the inorganic powder of the component (C) present in the composition is collected on the substrate side. As glass powder, lead borosilicate, bismuth borosilicate, zinc borosilicate, alkali metal borosilicate, alkaline earth metal borosilicate,
Lead borate-based, lead silicate-based glass frit is exemplified, and the dielectric is fired close to the electrode like a discharge display tube,
Since it is formed, it can be fired at a temperature that does not affect them and at a temperature at which the panel is not distorted.
Those having a temperature of 80 ° C. or lower are preferred. The shape is not particularly limited,
The particle size is usually 0.1 to 10 μm, and 0.2 to 5 μm
Is preferred.

The amount of component (B) in the composition to be calcined is 0.1 to 30 parts by weight, preferably 0.5 to 20 parts by weight, per 100 parts by weight of component (A). If the amount is less than 0.1 part by weight, the above effects cannot be sufficiently obtained, and
If the amount exceeds 0 parts by weight, the electric resistance of the obtained fired body increases.

The black inorganic powder of the component (C) is a characteristic component for solving the problem of color tone in the fired body electrode of the present invention. Inorganic powders exhibiting black color include metal composite oxides such as chromium-cobalt-manganese-iron, chromium-copper, chromium-copper-manganese, manganese-iron-copper, and chromium-cobalt-iron; (FeO) _x (Fe ₂ O ₃ ) Any iron oxide represented by _y , ruthenium oxide, carbon, etc., as long as it has heat resistance and is stable within the temperature range to which the glass substrate is exposed in the process of manufacturing the gas discharge display panel. It may be something. The shape is not particularly limited, and any shape such as a sphere, a scale, a needle, and an irregular shape can be used. The particle size is usually from 0.01 to 10 μm, preferably from 0.02 to 5 μm.

The compounding amount of the inorganic powder exhibiting the black component (C) can be arbitrarily set according to the design of the gas discharge display panel, but it satisfies both the electric resistance and the color tone of the interface between the electrode and the glass substrate. Therefore, the amount is 0.5 to 20 parts by weight, preferably 1 to 10 parts by weight based on 100 parts by weight of the component (A). If the amount is less than 0.5 parts by weight, the electrical resistance is sufficiently low and good, but the effect of distinguishing the interface color between the electrode and the glass substrate cannot be expected. On the other hand, if it exceeds 20 parts by weight, the color tone at the interface between the electrode and the glass substrate becomes sufficiently black and the discrimination is good, but the electric resistance increases.

The composition is prepared in the form of a paste by dispersing the silver powder, the glass powder and the black inorganic powder in a vehicle made of a photosensitive resin composition by a three-roll mill, a kneader or the like. .

As the photosensitive resin composition, those containing a photosensitive resin and / or a precursor thereof, a photopolymerization initiator, a solvent and the like are used.

As the photosensitive resin and / or its precursor, any of a negative type, a positive type and a negative-positive type may be used. However, since the handling is easy and the design is also easy,
Negative types are preferred. Such a negative photosensitive resin and / or a precursor thereof includes a linear or branched reactive polymer alone; and a photosensitive group such as an acryloyl group in a molecular structure. A monomer or oligomer that forms an insoluble polymer by polymerization and / or cross-linking upon exposure to light, such as an acrylic ester-based or epoxy-based (meth) acrylic acid derivative; or is compatible with the reactive polymer. Can be used in combination with the non-reactive polymer.

As the linear or branched reactive polymer, a polymer or copolymer of (meth) acrylic acid and / or an ester thereof, or a copolymer of such a monomer with a styrene compound and / or acrylonitrile can be used. Acrylics such as polymers modified to have (meth) acrylic groups in the side chains of the union; unsaturated polyesters, polyesters such as (meth) acrylates of polyester polyols; polyethylene glycol (meth) acrylate, polypropylene glycol (Meta)
Polyether (meth) acrylates such as acrylates; bisphenol-type epoxy resins, novolak-type epoxy resins or alicyclic epoxy resins obtained from the reaction of acrylic acid with acrylic acid; polyether polyol or polyester polyol with diisocyanate and hydroxy Examples include urethane (meth) acrylates obtained by reaction with group-containing (meth) acrylates; polymers such as polyimides such as copolymers of biphenyltetracarboxylic dianhydride and 2- (meth) acrylamide-diaminodiphenyl ether. Is done. Further, as the monomer or oligomer, in addition to the oligomer having a low degree of polymerization of the above polymer, diethylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol tri or Examples of the monomer include acrylic ester-based monomers such as tetraacrylate and dipentaerythritol hexaacrylate; and epoxy-based monomers such as bisphenol A-di (meth) acrylate.

The amount of the photosensitive resin and / or the precursor is adjusted so as to impart good photosensitivity to the conductive composition.
(A) Usually 5 to 20 parts by weight per 100 parts by weight of the component,
Preferably it is 10 to 15 parts by weight.

Examples of the photopolymerization initiator include radical photopolymerization initiators that generate free radicals when exposed to actinic rays such as ultraviolet rays, for example, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl- 1
Acetophenones such as -phenylpropan-1-one; benzophenones such as benzophenone and 3,3'-dimethyl-4-methoxybenzophenone; thioxanthones such as thioxanthone and diethylthioxanthone. These photopolymerization initiators can be used alone, in combination of two or more, or in combination with a photopolymerization accelerator such as amines.

An organic solvent can be used to dissolve the photosensitive resin composition or disperse the conductive composition to adjust the apparent viscosity. Organic solvents include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, amylbenzene, p-cymene, tetralin and petroleum aromatic hydrocarbon mixtures; menthol, terpineol, carpeol, borneol, menthandiol, etc. Terpene alcohols; 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, ether alcohols such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether; ketones such as methyl isobutyl ketone; and ethylene glycol monomethyl ether acetate And the like, and may be used alone or as a mixture of two or more.

Furthermore, a polymerization inhibitor such as hydroquinone monomethyl ether; a dispersant such as polyacrylate or a cellulose derivative; and a base material, for obtaining stability during storage in the conductive composition used in the present invention. Adhesives such as silane coupling agents to improve adhesiveness to the surface; antifoaming agents to improve coating performance; plasticizers to improve workability; thixotropic agents; UV absorption An ultraviolet absorber or the like for increasing efficiency can be added.

The concentration of the conductive composition may be an apparent viscosity suitable for a coating or printing method. For example, in the case of screen printing, a paste in a range of usually 20 to 500 Pa · s, preferably 100 to 300 Pa · s at 25 ° C. It can be arbitrarily determined as obtained.

The paste of the conductive composition thus obtained is printed or coated on the surface of the base material by a known method such as screen printing or a roll coater. After removing the organic solvent from the paste printed or applied on the base material surface by a conventional method such as air-drying, through a photomask, ultraviolet rays, far ultraviolet rays, an electron beam, an active ray such as an ion beam. Then, the pattern portion is exposed. Ultraviolet rays are preferred as the actinic ray because they can be easily irradiated with a relatively simple device. Next, development is performed with a developer, and the cleaning liquid is removed by a method such as drying to form a pattern.

The conductive composition having the pattern thus formed is baked at, for example, 500 to 580 ° C. for 10 to 20 minutes to form the conductive baked body of the present invention on the surface of the substrate.

By such a method, an electrode comprising the conductive fired body of the present invention can be obtained using the above-mentioned conductive composition. In particular, the AC or DC gas discharge display panel of the present invention can be obtained by forming the bus electrode of the AC gas discharge display panel having the above-described structure or the anode of the DC gas discharge display panel. Other components of the gas discharge display panel, such as the substrate, the transparent electrode, the dielectric layer, the protective layer, the phosphor, the address electrode, and the cathode, can be formed by using a conventionally known material and a forming method.

[0036]

According to the present invention, the conductive fired body has a low electric resistance and can make the color tone of the interface between silver and the glass substrate black. If this is used as a bus electrode or anode formed on the display surface side substrate of the gas discharge display panel, not only the electric resistance is low, but also a black stripe effect can be obtained. Problems in display quality such as a decrease in display contrast and a shift in displayed color tone that occur sometimes can be solved.

Further, by applying the fired body of the present invention to the wiring formed on the surface of the glass substrate by photolithography similarly to the electrode, the pattern accuracy is high, the electric resistance is low,
Wiring that can be easily identified by the naked eye can be formed.

[0038]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. In these examples, parts represent parts by weight. The present invention is not limited by these examples.

Examples 1-5 Silver powder (average particle size 0.7 μm, spherical particles), glass powder (lead borosilicate glass, softening temperature about 480 ° C., average particle size 3 μm, spherical particles) and manganese-iron-copper A composite oxide powder (average particle size: 0.1 μm, spherical particles) was prepared at a compounding ratio as shown in Table 1. This was converted to a resin component of a photosensitive resin composition which was a solution having a viscosity of about 20 Pa · s, in which a methacrylic acid-modified copolymer of acrylic acid and 2-hydroxyethyl acrylate was dissolved in diethylene glycol monobutyl ether. And kneaded with a kneader together with 14 parts to prepare a paste.

Next, these pastes were respectively printed on the top surface and the bottom surface (Sn adhesion) of the soda lime glass substrate by screen printing, and dried at 100 ° C. for 10 minutes. Contact, with a high pressure mercury lamp, line width and line spacing are each 50μm
Alternatively, the substrate was exposed to ultraviolet light having a main wavelength of 365 nm at 500 mJ / cm ² so as to form a pattern of 100 μm. After exposure,
The above pattern was developed by spraying a 1% by weight aqueous solution of sodium carbonate as a developing solution by spraying onto the surface of the coating film under pressure at room temperature. After development, the developer is washed away with pure water,
For 10 minutes. Then, the sample was fired at 550 ° C. for 10 minutes to prepare an evaluation sample.

The color tone, developability, and sheet resistance of the obtained sample were measured when observed from the back side (the side on which no printing was performed) of the glass substrate. Table 1 shows the results.

[0042]

[Table 1]

Examples 6 to 10 Silver powder (average particle size 1 μm, spherical particles), glass powder (lead borosilicate glass, softening temperature about 450 ° C., average particle size 4 μm)
m, spherical particles) and a chromium-copper composite oxide powder (average particle size: 0.8 μm, spherical particles) were prepared at the compounding ratio shown in Table 2. This was kneaded with a kneader together with 14 parts of the same photosensitive resin composition as used in Examples 1 to 5 to obtain a paste.

Next, these pastes were used in Examples 1 to 5
An evaluation sample was prepared by treating in the same manner as described above.

The color tone, developability and sheet resistance of the obtained sample were measured when observed from the back side (the side on which no printing was performed) of the glass substrate. Table 2 shows the results.

[0046]

[Table 2]

Examples 11 to 16 Silver powder (average particle size 0.5 μm, spherical particles), glass powder (bismuth borosilicate glass, softening temperature about 500 ° C., average particle size 2 μm, spherical particles) and ruthenium oxide powder (average particle size) (Spherical particles having a particle size of 0.05 μm) were prepared at a compounding ratio as shown in Table 3. Together with 14 parts of the same photosensitive resin composition as the resin used in Examples 1 to 10,
It was made into a paste by kneading using a kneader.

Next, these pastes were used in Examples 1 to 1
An evaluation sample was prepared by treating in the same manner as in Example 1.

The color tone, developability and sheet resistance of the obtained sample were measured when observed from the back side (non-printed side) of the glass substrate. Table 3 shows the results.

[0050]

[Table 3]

Comparative Examples 1-4 Using the silver powder and glass powder used in Examples 1-5,
Silver paste of Comparative Example 1 containing no black inorganic fine powder; Paste of Comparative Example 2 obtained by blending a small amount of manganese-iron-copper composite oxide with similar powder; used in Examples 6 to 10 Using silver powder and glass powder, a small amount of chromium
Paste of Comparative Example 3 obtained by blending a copper composite oxide; and Comparative Example 4 blending a large amount of ruthenium oxide powder using silver powder and glass powder used in Examples 11 to 16.
Was processed in the same manner as in each example to produce an evaluation sample. About the obtained sample, the color tone was observed and the sheet resistance was measured in the same manner as in the example. Table 4 shows the results.

[0052]

[Table 4]

The fired bodies of the present invention obtained in Examples 1 to 16 exhibited a dark color with sufficient display contrast, and exhibited excellent conductivity. On the other hand, Comparative Examples 1 to
The fired body obtained in Example 3 had insufficient display contrast, and the fired body obtained in Comparative Example 4 did not have satisfactory conductivity.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a basic structure of a typical gas discharge display panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Display side substrate 2 Back side substrate 3 Transparent electrode 4 Bus electrode 5 Dielectric layer 6 Protective layer 7 Dielectric layer 8 Address electrode 9 Partition 10 Fluorescent substance 11 Observer

Claims (4)

[Claims] 1. A photosensitive composition comprising: (A) 100 parts by weight of silver powder; (B) 0.1 to 30 parts by weight of glass powder; and (C) 0.5 to 20 parts by weight of a black inorganic powder. A conductive fired body obtained by forming a pattern by photolithography using a conductive composition and then firing. 2. An electrode comprising the conductive fired body according to claim 1. 3. A pair of substrates facing each other across a discharge space, provided on at least one of the substrates, a discharge sustaining electrode comprising a transparent electrode and a bus electrode, and sequentially provided inside the discharge sustaining electrode. An AC-type gas discharge display panel provided with a dielectric layer and a protective layer, wherein the bus electrode is the electrode according to claim 2. 4. A direct current type gas discharge display panel comprising a pair of substrates facing each other across a discharge space, an anode provided on an inner surface of one substrate, and a cathode provided on an inner surface of the other substrate. 3. A gas discharge display panel, wherein the anode is the electrode according to claim 2.