JP3674116B2 - Electrode for plasma display panel and plasma display panel - Google Patents

Description

【００６０】
【発明の効果】
ガラス基板との接着強度が強く、抵抗値が低い電極を有するプラズマディスプレイパネルを形成することができた。
【００６１】
また、該電極組成は、原料を感光性ペースト化することによって、高精度のパターン形成が実現でき、高精細プラズマディスプレイに対して有用である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma display panel (PDP) having electrodes with high definition and low resistance.
[0002]
[Prior art]
A plasma display panel (PDP) is capable of displaying at a higher speed than a liquid crystal panel and is easy to increase in size, and thus has penetrated into fields such as OA equipment and information display devices. In addition, progress in the field of high-definition television is highly expected.
[0003]
Along with the expansion of such applications, a color PDP having a fine PDP and a large number of display cells has attracted attention. The PDP generates a plasma discharge between electrodes opposed to each other in a discharge space provided between the front glass substrate and the rear glass substrate, and performs display by emitting light from a gas sealed in the discharge space. Is.
[0004]
In this case, the electrodes on the glass substrate are arranged such that a plurality of linear electrodes are arranged in parallel so that the electrodes face each other through a small gap and the linear electrodes cross each other. It is configured to overlap.
[0005]
The electrodes are usually formed by screen printing, printing silver paste on a glass substrate, and then firing.
[0006]
However, in the screen printing method, it is difficult to reduce the width of the electrode pattern to 100 μm or less even if the mask pattern accuracy, squeeze hardness, printing speed, dispersibility, etc. are optimized, and there is a limit to fine patterning. It was.
[0007]
In the screen printing method, the accuracy of the printing mask depends on the accuracy of the mask plate making. Therefore, when the printing mask becomes large, the dimensional error of the mask pattern increases. For this reason, in the case of a PDP having a large area of 20 inches or more, it is increasingly technically difficult to produce a high-definition PDP.
[0008]
As a method for improving these screen printing defects, as described in JP-A-1-206538, JP-A-1-296534 and JP-A-63-205255, an insulating paste is baked and then a conductive paste. Printed and fired to improve electrode shape, anode electrode formation using photolithography technology, and conductive paste using photolithography technology using photoresist have been proposed. In addition, it has not been sufficient as a technique for obtaining an electrode having good adhesion to a glass substrate, low resistance and suitable for enlargement.
[0009]
[Problems to be solved by the invention]
An object of the present invention is to provide an electrode for a plasma display panel that can form a fine pattern, has high adhesive strength with a glass substrate, has low resistance, and is suitable for upsizing. Is to provide.
[0010]
[Means for Solving the Problems]
The purpose of such invention, on a glass substrate, electrically and conductive metal from 96.7 to 99 wt%, the glass transition temperature to form as an essential component and a glass component from 1 to 3.3% by weight of 300 to 500 ° C. This is achieved by an electrode for a plasma display panel and a plasma display panel having the electrode.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The conductive metal used in the present invention is not particularly limited. For example, the conductive metal contains at least one of Ag, Au, Pd, Cu, Ni, Al, and Pt. Can be used as Examples of the mixed powder are Ag (80 to 98) -Pd (20-2), Ag (90-98) -Pd (10-2) -Pt (2-10), Ag (85-98)- A ternary or binary mixed noble metal powder such as Pt (15-2) (in the above () represents weight%) is used.
[0012]
Moreover, when using it for the front substrate of PDP, the contrast of a display can be improved by blackening an electrode. As a method for this purpose, blackening by a silver-nickel alloy or a combination of silver powder and nickel powder is effective. In this case, from the viewpoint of resistance value, the silver content is preferably 70% by weight or more.
[0013]
Moreover, in this invention, it is preferable to use the electroconductive metal which can be baked on the glass substrate at the temperature of 600 degrees C or less, and it is preferable that silver is contained in 70-100 weight%.
[0014]
It is essential for the electrode to contain a glass component in addition to the conductive metal. A glass component is used in order to ensure sufficient adhesive force of an electroconductive metal and a glass substrate. Moreover, working a conductive metal powder as a sintering agent in baked on a glass substrate, it is effective to reduce the resistance value.
[0015]
The glass transition temperature (Tg) and the glass softening temperature (Ts) of the glass component are preferably low, and are preferably 300 to 500 ° C. and 350 to 450 ° C., respectively. More preferably, Tg is 350 to 450 ° C. If Tg is too low, sintering is started before organic components such as a binder described later evaporate, which is not preferable. When Tg exceeds 500 ° C., adhesion with a glass substrate tends to be inferior when performed at a baking temperature of 600 ° C. or less, which is not preferable.
[0016]
Glass component, a glass powder (hereinafter glass frit) to allow mixing with ordinary conductive metal powder as a raw material. The glass frit preferably contains Bi ₂ O ₃ in the range of 10 to 80% by weight. When the content is less than 10% by weight, it is not sufficient to control the glass transition point and the softening point when baking the conductive paste on the glass substrate, and is less effective in increasing the adhesive strength to the substrate. Also, too low softening point of the glass frit becomes more than 80 wt% glass frit is melted before the binder in the paste evaporates, it becomes poor debinding of this for paste, sintering of the conductive film And the adhesive strength with the substrate tends to decrease.
[0017]
Furthermore, in the present invention, in oxide conversion notation,
Bi ₂ O ₃ 30-70% by weight
SiO ₂ 3-30% by weight
B ₂ O ₃ 2-25% by weight
ZnO 2-20% by weight
It is preferable to use a glass component having the above composition range because the electrode can be firmly baked on a glass substrate at 500 to 600 ° C.
[0018]
SiO ₂ is preferably blended in the range of 3 to 30% by weight, and if it is less than 3% by weight, the adhesive strength and the stability of the glass component are apt to decrease when baked on the substrate. On the other hand, if it exceeds 30% by weight, the heat-resistant temperature increases, and baking at 600 ° C. or less tends to be difficult.
[0019]
B ₂ O ₃ is preferably blended in the range of 2 to 25% by weight. B ₂ O ₃ is blended in order to control the baking temperature in the range of 500 to 600 ° C. so as not to impair the electrical, mechanical and thermal properties such as the electrical insulation, strength and thermal expansion coefficient of the electrode. If it is less than 2% by weight, the adhesion strength is lowered, and if it exceeds 25% by weight, the stability of the glass component tends to be lowered.
[0020]
ZnO is preferably blended in the range of 2 to 20% by weight. If it is less than 2% by weight, it is less effective for controlling the baking temperature when the electrode is baked on the glass substrate. If it exceeds 20% by weight, the heat resistance temperature of the glass component becomes too low, and baking onto the glass substrate tends to be difficult.
[0021]
It is preferable that the glass component does not contain an oxide metal such as Na ₂ O, Y ₂ O ₃ , or K ₂ O that deteriorates the discharge characteristics of plasma. Even when it is contained, it is 3% by weight or less.
[0022]
In addition, by containing Al ₂ O ₃ , BaO, CaO, TiO ₂ 2, ZrO ₂ , Li ₂ O, etc. in the glass component , the thermal expansion coefficient, glass softening point, glass transition point, insulation resistance can be controlled, The amount is preferably less than 15% by weight.
[0023]
It is important that the glass component content in the electrode is 1 to 3.3% by weight . In order to reduce the resistance of the electrode of the PDP, it is preferable that the amount of the glass component is low.
[0024]
Since the glass component is electrode insulating, if the content exceeds 5% by weight, the resistance of the electrode increases, which is not preferable. If it is 1% by weight or less, it is difficult to obtain a strong adhesive strength between the electrode film and the glass substrate.
[0025]
In recent years, in order to improve the fineness of the PDP, studies using a photosensitive paste composed of a photosensitive organic component and a conductive metal component have been actively conducted in order to form electrodes with high definition.
[0026]
The electrode of the present invention is also referred to as mask exposure, development, and baking after preparing a conductive conductive powder composed of conductive metal powder having the above composition and glass frit of the glass component having the above composition, and applying it on a glass substrate. It can be formed using a general photolithography process.
[0027]
In this case, the total content of metal oxides such as PbO, CaO, BaO, Fe ₂ O ₃ , K ₂ O, and Na ₂ O is 3% by weight or less with respect to the total of the conductive metal and the glass component. As a result, development with an aqueous developer is possible.
[0028]
When the content of these components is 3% by weight or more, when acidic groups such as carboxyl groups are present in the photosensitive organic component, these components and acidic groups cause an ionic crosslinking reaction, and the paste gels in a short time. Therefore, productivity is reduced.
[0029]
In order to form an electrode using a photosensitive paste capable of high definition, the content of these metal oxides is preferably 1% by weight or less.
[0030]
In the present invention, when a metal and / or metal oxide is added as a sintering aid in addition to the above-described conductive metal and glass component , abnormal particle growth of the conductive powder can be avoided during sintering, or sintering is delayed. It is preferable because of the effects such as. As a result, the adhesive strength between the conductor film and the glass substrate can be increased.
[0031]
As such a sintering aid, metals and / or metal oxides such as Cu, Cr, Mo, Al or Ni can be used.
Among these, the metal oxide acts as an electrical insulator, so the amount of the additive is preferably small, and is 3% by weight or less based on the total of the conductive metal and the glass component. If it exceeds 3% by weight, the electrical resistance of the electrode increases, which is not preferable. Further, it is also preferable to use a metal oxide and a metal in combination.
[0032]
When an electrode is formed using the conductive metal and glass component of the present invention, a high-definition pattern is possible. That is, when the thickness of the conductor film after sintering is 3 to 30 μm, the line width of the conductor is 5 to 100 μm, and the line interval between conductors is 10 to 500 μm.
[0033]
The glass substrate used for the PDP of the present invention is not particularly limited as long as it is a known one, but ordinary soda glass, borosilicate glass-based low alkali glass or non-alkali glass, high strain point float glass (trade name, Asahi Glass) PD-200) manufactured by the company can be used.
[0034]
Moreover, although an electrode is normally formed by baking the composition containing an electroconductive metal and a glass component on a glass substrate, baking is 500-600 degreeC, More preferably, it is 520-580 degreeC for 15 minutes-1 hour. It is preferable to bake and bake on a glass substrate. If it is less than 500 ° C., it is difficult to perform firing sufficiently, and if it exceeds 600 ° C., the glass substrate is likely to be deteriorated or thermally deformed.
[0035]
Using the glass substrate on which the electrode conductor film is formed by the above-described method, for example, a plasma display panel can be produced by the following procedure.
[0036]
The front substrate of the plasma display can be created by the following procedure.
(1) A dielectric glass paste is applied on a substrate by a screen printing method or the like and then baked to provide a dielectric layer.
(2) A magnesium oxide layer is formed on the surface of the dielectric layer by an electron beam evaporation method or the like.
[0037]
Moreover, the back substrate of a plasma display can be created by the following procedure.
[0038]
(1) A photosensitive glass paste is applied on a substrate by a doctor blade method or the like, and then a partition wall is formed by each process of drying-exposure-development-firing.
(2) A phosphor layer is formed in the partition wall by screen printing. For forming the phosphor layer, an ink jet method, a sand blast method, or the like can also be used.
[0039]
A plasma display panel can be created by combining a front substrate and a rear substrate and enclosing a rare gas therein.
[0040]
Further, the electrode of the present invention can be used for display devices having a discharge mechanism in general, and forms an electrode in a discharge portion of an AC type plasma display, a DC type plasma display, and a plasma addressed liquid crystal display combining plasma discharge and liquid crystal display. Etc. can be used.
[0041]
【Example】
The following examples illustrate the invention. In the examples, electrodes were formed and evaluated by the following materials A to K and a to e.
[0042]
In the following examples, all concentrations are expressed in weight percent unless otherwise specified.
[0043]
A. As the conductive powder, the following powder was used.
[0044]
(1) Ag powder: monodisperse granular, average particle size 3.7 μm, specific surface area 0.48 m ² / g
(2) 95% Ag-5% Pd powder; monodisperse granular, average particle size 3.3 μm, specific surface area 0.82 m ² / g
(3) 95% Ag-5% Ni powder; monodisperse granular, average particle size 3.8 μm, specific surface area 0.80 m ² / g
The particle size distribution was measured with a laser particle size distribution measuring device (HORIBALA-700).
[0045]
B. Acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in the side chain (hereinafter abbreviated as polymer)
Add 0.4 equivalents of glycidyl methacrylate (GMA) to MAA to a copolymer consisting of 40% methacrylic acid (MAA), 30% methyl methacrylate (MMA) and 30% styrene (St). Reacted polymer.
[0046]
C. Photosensitive monomer (hereinafter abbreviated as monomer)
Trimethylolpropane triacrylate The following five types of glass frit were used.
[0047]
Glass frit I (component weight%) bismuth oxide (45.1), silicon dioxide (27.5), boron oxide (12.5), zinc oxide (2.6), sodium oxide (4.7), oxidation Aluminum (2.8), Zirconium oxide (4.8)
Glass frit II (component weight%) bismuth oxide (50), silicon dioxide (7), boron oxide (15), zinc oxide (14), barium oxide (14)
Glass frit III; (component weight%) Bismuth oxide (66.9), silicon dioxide (10), boron oxide (11.8), zinc oxide (2.6), aluminum oxide (2.8), zirconium oxide ( 4.8)
F. Solvent γ-butyrolactone G. Photopolymerization initiators 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropanone-1 and 2,4-diethylthioxanthone were added in an amount of 20% based on the sum of the polymer and the monomer.
[0048]
H. The plasticizer dibutyl phthalate (DBP) was added 10% of the polymer.
[0049]
I. The sensitizer 2,4-diethylthioxanthone was added in an amount of 5% based on the sum of the polymer and the monomer.
[0050]
J. et al. Sensitization aid p-dimethylaminobenzoic acid ethyl ester (EPA) was added at 2% based on the sum of the polymer and the monomer.
[0051]
K. An SiO ₂ concentration of 15% dissolved in the thickener 2- (2-butoxyethoxy) ethyl acetate was added to the polymer at 4%.
[0052]
a. Production solvent of photosensitive conductive paste and polymer were mixed and heated to 80 ° C. with stirring to dissolve all the polymers homogeneously. Next, the solution was cooled to room temperature, and a photopolymerization initiator was added and dissolved. The solution was then filtered through a 400 mesh filter. Then, conductive powder, monomer, plasticizer, sensitizer, sensitizer, thickener, glass frit and solvent are added so as to have a predetermined composition, and the paste is mixed and dispersed with three rollers. Produced.
[0053]
b. Printing The above paste was printed on a glass substrate (430 mm square, 3 mm thick) on a 400 mm square using a 325 mesh screen, dried at 80 ° C. for 40 minutes. The thickness of the coating film after drying was 12 to 15 μm.
[0054]
c. Exposure and Development The coating film prepared above was exposed to ultraviolet rays with an ultrahigh pressure mercury lamp having an output of 500 mW / cm ² from the upper surface using a chromium mask on which an electrode for a plasma display panel having a fine pattern of 40 to 70 μm was formed. Next, it was developed by being immersed in a 0.5 wt% aqueous solution of monoethanolamine maintained at 25 ° C., and then the unexposed area was washed with water using a spray.
[0055]
d. The coating film printed on the baked glass substrate was baked in air at 580 ° C. for 15 minutes to produce an electrode conductor film, which was used as an electrode.
[0056]
e. About the electrode after evaluation baking, pattern shape, specific resistance, and adhesive strength were measured. The pattern shape was determined by observing the cross section with a scanning electron microscope (SEM). The adhesive strength was evaluated by sticking an adhesive tape to the electrode surface and the degree of peeling. The specific resistance was calculated from the film thickness by measuring the sheet resistance after forming a 10 μm thick electrode.
The evaluation results are shown in Table 1.
[0057]
Example 1
According to the above procedure, the electrode for plasma display was formed using (1) as the conductive powder, glass frit and I.
The characteristics of the obtained electrode are shown in Table 1.
[0058]
Examples 2-6
Table 1 shows the results of forming and evaluating electrodes in the same manner as in Example 1.
[0059]
[Table 1]

[0060]
【The invention's effect】
A plasma display panel having an electrode having high adhesion strength with a glass substrate and low resistance value could be formed.
[0061]
The electrode composition can be used for a high-definition plasma display because a highly accurate pattern can be formed by converting the raw material into a photosensitive paste.

Claims (7)

On a glass substrate, a plasma display panel that electrically and conductive metal from 96.7 to 99 wt%, that the glass transition temperature to form as an essential component and a glass component from 1 to 3.3% by weight of 300 to 500 ° C. wherein Electrode.   The electrode for plasma display according to claim 1, wherein the conductive metal contains 70 to 100% by weight of silver. Glass components constituting the electrodes, the plasma display panel electrode according to claim 1 or 2, characterized in that it contains the Bi ₂ O ₃ in the range of 10 to 80 wt%. The glass component constituting the electrode is expressed in terms of oxide,
Bi ₂ O ₃ 30-70% by weight
SiO ₂ 3-30% by weight
B ₂ O ₃ 2-25% by weight
ZnO 2-20% by weight
The electrode for a plasma display panel according to any one of claims 1 to 3, wherein the composition range is as follows. The plasma display panel according to any one of claims 1 to 4, wherein the total content of Na ₂ O, K ₂ O, and PbO in the glass component constituting the electrode is in the range of 3% by weight or less. Electrode. Electrode thickness is 3 to 30 .mu.m, the minimum line width 5 to 100 [mu] m, a plasma display electrode according to any one of claims 1-5, characterized in that it has a shape of a minimum line spacing 10~500μm between electrodes. A plasma display panel characterized by having the electrode according to any of claims 1-6.