WO2012017632A1

WO2012017632A1 - Electrode paste for plasma display panel, and method for producing plasma display panel

Info

Publication number: WO2012017632A1
Application number: PCT/JP2011/004310
Authority: WO
Inventors: 筒井　靖貴; 覚河瀬
Original assignee: パナソニック株式会社
Priority date: 2010-08-04
Filing date: 2011-07-29
Publication date: 2012-02-09

Abstract

A method for producing a plasma display panel provides 15 vol. % to 25 vol. % conductive particles, 10 vol. % to 25 vol. % organic resin, and 10 vol. % to 20 vol. % monomers. By applying an electrode paste containing acrylic polymers and cellulose polymers to the front glass substrate, the organic resin forms an electrode paste layer. Next, by shaping the electrode paste layer, an electrode pattern is formed in which at least the organic resin remains. Next, by applying a dielectric paste to the front glass substrate, a dielectric paste film that covers the electrode pattern is formed. Next, by simultaneously firing the electrode pattern and the dielectric paste, a display electrode and a dielectric layer are formed.

Description

Electrode paste for plasma display panel and method for manufacturing plasma display panel

The technology disclosed herein relates to an electrode paste for a plasma display panel used for a display device or the like and a method for manufacturing the plasma display panel.

Silver electrodes for ensuring conductivity are used for bus electrodes constituting display electrodes of a plasma display panel (hereinafter referred to as PDP). Low-melting glass is used for the dielectric layer covering the bus electrode.

For example, Patent Document 1 discloses a technique for reducing voids in a dielectric layer by using a screen printing method and a die coating method in combination. For example, Patent Document 2 discloses a technique for forming a dielectric layer by a dry film method.

JP 2002-25433 A Japanese Patent Laid-Open No. 2004-63420

The electrode paste for PDP comprises 15% by volume to 25% by volume conductive particles, 10% by volume to 25% by volume organic resin, and 10% by volume to 20% by volume monomer. The organic resin includes an acrylic polymer and a cellulose polymer.

In the PDP manufacturing method, the electrode paste layer is formed by applying the electrode paste for PDP to the substrate. Next, the electrode paste layer is shaped to form an electrode pattern in which at least the organic resin remains. Next, a dielectric paste layer for covering the electrode pattern is formed by applying a dielectric paste to the substrate. Next, the electrode pattern and the dielectric paste layer are simultaneously fired to form the electrode and the dielectric layer.

FIG. 1 is a perspective view showing the structure of the PDP according to the embodiment. FIG. 2 is a schematic view showing a cross section of the front plate according to the embodiment. FIG. 3A is a schematic view illustrating a manufacturing process of the front plate according to the embodiment. FIG. 3B is a schematic view illustrating a manufacturing process of the front plate according to the embodiment. FIG. 3C is a schematic diagram illustrating a manufacturing process of the front plate according to the embodiment. FIG. 3D is a schematic view illustrating a manufacturing process of the front plate according to the embodiment. FIG. 3E is a schematic diagram illustrating a manufacturing process of the front plate according to the embodiment. FIG. 4A is a diagram illustrating a chemical formula of a solvent of the dielectric paste according to the embodiment. FIG. 4B is a diagram illustrating a chemical formula of a solvent of the dielectric paste according to the embodiment. FIG. 4C is a diagram illustrating a chemical formula of a solvent of the dielectric paste according to the exemplary embodiment. FIG. 4D is a diagram illustrating a chemical formula of a solvent of the dielectric paste according to the embodiment.

[1. Configuration of PDP1]
The PDP 1 of the present embodiment is an AC surface discharge type PDP. As shown in FIG. 1, in the PDP 1, a front plate 2 made of a front glass substrate 3 and the like and a back plate 10 made of a back glass substrate 11 and the like are arranged to face each other. The outer peripheral portions of the front plate 2 and the back plate 10 are hermetically sealed with a sealing material made of glass frit or the like. A discharge gas containing xenon (Xe) is sealed in the discharge space 16 inside the sealed PDP 1 at a pressure of 55 kPa to 80 kPa.

On the front glass substrate 3, a pair of strip-shaped display electrodes 6 each composed of the scanning electrodes 4 and the sustaining electrodes 5 and a plurality of light shielding layers 7 are arranged in parallel to each other. The scanning electrode 4 is composed of a black electrode 4a and a white electrode 4b stacked on the black electrode 4a. The sustain electrode 5 includes a black electrode 5a and a white electrode 5b laminated on the black electrode 5a. Furthermore, a dielectric layer 8 that covers the display electrode 6 and the light shielding layer 7 is formed on the front glass substrate 3. The dielectric layer 8 functions as a capacitor. Further, a protective layer 9 made of magnesium oxide (MgO) or the like is formed on the surface of the dielectric layer 8.

On the rear glass substrate 11, a plurality of strip-like address electrodes 12 are arranged in parallel to each other in a direction orthogonal to the display electrodes 6. Further, a base dielectric layer 13 that covers the address electrodes 12 is formed. Further, on the base dielectric layer 13 formed between the address electrodes 12, barrier ribs 14 having a predetermined height are formed to divide the discharge space 16. Between the barrier ribs 14, a phosphor layer 15 that emits red light by ultraviolet rays, a phosphor layer 15 that emits blue light, and a phosphor layer 15 that emits green light are sequentially formed.

A discharge cell is formed at a position where the display electrode 6 and the address electrode 12 intersect. A discharge cell having a phosphor layer 15 that emits red light, a discharge cell that has a phosphor layer 15 that emits blue light, and a discharge cell that has a phosphor layer 15 that emits green light form a pixel for color display. The

[2. Manufacturing method of PDP1]
[2-1. Manufacturing method of front plate 2]
As shown in FIG. 2, scan electrode 4 and sustain electrode 5 are formed on front glass substrate 3. The display electrode 6 has a scan electrode 4 and a sustain electrode 5. Scan electrode 4 and sustain electrode 5 contain silver (Ag) for ensuring conductivity.

By the way, many production facilities are required in the conventional method of forming a dielectric material multiple times. Furthermore, the increase in energy consumption during production leads to an increase in cost, making it difficult to provide an inexpensive and high-performance PDP. In addition, the dry film method requires a base film for forming a dry film, which not only leads to an increase in cost, but is also undesirable in terms of environmental problems because the base film becomes waste after lamination. Further, in the dry film method, it is difficult to form without a gap because the fluidity at the display electrode interval is poor at the time of formation.

In the conventional method of manufacturing a front panel of a PDP, a display electrode is formed in a stripe shape by a printing method and a photolithography method, and after a firing process, a dielectric layer is formed. However, performing each baking step to form the display electrode and the dielectric layer leads to an increase in energy consumption and an increase in cost. Therefore, reduction of the firing process is desired.

The dielectric layer 8 according to the present embodiment is composed of the first glass material 20 and the second glass material 21. The dielectric layer is formed so as to cover the display electrode 6 and the light shielding layer 7. The method for forming the display electrode 6 and the method for forming the dielectric layer 8 will be described in detail later.

Next, a protective layer 9 made of magnesium oxide (MgO) or the like is formed on the dielectric layer 8 by a vacuum deposition method or the like. As described above, the front plate 2 is formed.

[2-2. Manufacturing method of back plate 10]
As shown in FIG. 1, an address electrode 12, a base dielectric layer 13, a partition wall 14, and a phosphor layer 15 are formed on a back glass substrate 11.

First, address electrodes 12 are formed on the back glass substrate 11 by photolithography. As the material of the address electrode 12, an address electrode paste containing silver (Ag) for ensuring conductivity, a glass frit for binding silver, a photosensitive resin, a solvent, and the like is used. First, the address electrode paste is applied on the rear glass substrate 11 with a predetermined thickness by screen printing or the like. Next, the solvent in the address electrode paste is removed by a drying furnace. Next, the address electrode paste is exposed through a photomask having a predetermined pattern. Next, the address electrode paste is developed to form an address electrode pattern. Finally, the address electrode pattern is fired at a predetermined temperature in a firing furnace. That is, the photosensitive resin in the address electrode pattern is removed. Further, the glass frit in the address electrode pattern is melted. The molten glass frit is vitrified again after firing. The address electrode 12 is formed by the above process. Here, besides the method of screen printing the address electrode paste, a sputtering method, a vapor deposition method, or the like can be used.

Next, the base dielectric layer 13 is formed. As a material for the base dielectric layer 13, a base dielectric paste containing a dielectric glass frit, a resin, a solvent, and the like is used. First, a base dielectric paste is applied by a screen printing method or the like so as to cover the address electrodes 12 on the rear glass substrate 11 on which the address electrodes 12 are formed with a predetermined thickness. Next, the solvent in the base dielectric paste is removed by a drying furnace. Finally, the base dielectric paste is fired at a predetermined temperature in a firing furnace. That is, the resin in the base dielectric paste is removed. Further, the dielectric glass frit is melted. The molten dielectric glass frit is vitrified again after firing. Through the above steps, the base dielectric layer 13 is formed. Here, other than the method of screen printing the base dielectric paste, a die coating method, a spin coating method, or the like can be used. Further, a film that becomes the base dielectric layer 13 can be formed by CVD (Chemical Vapor Deposition) method or the like without using the base dielectric paste.

Next, the barrier ribs 14 are formed by photolithography. As a material for the partition wall 14, a partition paste containing a filler, a glass frit for binding the filler, a photosensitive resin, a solvent, and the like is used. First, the barrier rib paste is applied on the underlying dielectric layer 13 with a predetermined thickness by a die coating method or the like. Next, the solvent in the partition wall paste is removed by a drying furnace. Next, the barrier rib paste is exposed through a photomask having a predetermined pattern. Next, the barrier rib paste is developed to form a barrier rib pattern. Finally, the partition pattern is fired at a predetermined temperature in a firing furnace. That is, the photosensitive resin in the partition pattern is removed. Further, the glass frit in the partition wall pattern is melted. The molten glass frit is vitrified again after firing. The partition wall 14 is formed by the above process. Here, in addition to the photolithography method, a sandblast method or the like can be used.

Next, the phosphor layer 15 is formed. As the material of the phosphor layer 15, a phosphor paste containing phosphor particles, a binder, a solvent, and the like is used. First, the phosphor paste is applied with a predetermined thickness on the base dielectric layer 13 between the adjacent barrier ribs 14 and the side surfaces of the barrier ribs 14 by a dispensing method or the like. Next, the solvent in the phosphor paste is removed by a drying furnace. Finally, the phosphor paste is fired at a predetermined temperature in a firing furnace. That is, the resin in the phosphor paste is removed. The phosphor layer 15 is formed by the above steps. Here, in addition to the dispensing method, a screen printing method or the like can be used.

Through the above steps, the back plate 10 is formed.

[2-3. Assembly method of front plate 2 and rear plate 10]
First, a sealing material (not shown) is formed around the back plate 10 by the dispensing method. As a material for the sealing material (not shown), a sealing paste containing glass frit, a binder, a solvent, and the like is used. Next, the solvent in the sealing paste is removed by a drying furnace. Next, the front plate 2 and the back plate 10 are arranged to face each other so that the display electrodes 6 and the address electrodes 12 are orthogonal to each other. Next, the periphery of the front plate 2 and the back plate 10 is sealed with glass frit. Finally, a discharge gas containing 15 vol% or more and 30 vol% or less of Xe is sealed in the discharge space 16. As described above, the PDP 1 is formed.

[3. Details of Display Electrode 6]
[3-1. Composition of electrode paste for PDP]
When the display electrode 6 is formed using a material containing a binder component such as an organic resin or a solvent, baking is performed to remove the binder component. Further, when the dielectric layer 8 is formed using a material containing a binder component such as an organic resin or a solvent, firing is performed to remove the binder component. In the present embodiment, the firing for forming the display electrode 6 and the light shielding layer 7 which are electrodes and the firing for forming the dielectric layer 8 are performed in the same process (hereinafter, simply referred to as simultaneous firing). To do).

However, in the prior art, if the firing process of the display electrode is simply omitted and simultaneous firing is performed, there is a gap between the display electrode and the dielectric layer due to the difference in shrinkage between the display electrode and the dielectric paste. Will be formed. As a result, the capacity of the discharge cell changes and the discharge becomes unstable. Furthermore, the dielectric strength characteristics of the dielectric layer will be significantly degraded.

Therefore, in the present embodiment, by developing a PDP electrode paste (hereinafter referred to as an electrode paste) different from the conventional one, the above-described problems can be suppressed even if simultaneous firing is performed.

The electrode paste in the present embodiment includes 15% by volume to 25% by volume of conductive particles, 10% by volume to 25% by volume of an organic resin, and 10% by volume to 20% by volume of a monomer. . The organic resin includes an acrylic polymer and a cellulose polymer. Cellulose polymers have a higher viscosity per unit volume than acrylic polymers. Therefore, an electrode paste having a smaller amount of resin can be obtained even with the same viscosity as compared with an electrode paste that has been conventionally composed of only an acrylic polymer. In other words, in the present embodiment, the thickness of the display electrode pattern before firing, which is an electrode pattern, can be made smaller than before. Therefore, even if the display electrode pattern is fired simultaneously with the dielectric paste layer, the shrinkage of the display electrode pattern is suppressed. Therefore, it is possible to suppress the formation of a gap between the display electrode 6 and the dielectric layer 8.

The organic resin preferably contains 5% by volume to 15% by volume of acrylic polymer and 2% by volume to 10% by volume of cellulose polymer. Furthermore, as an organic resin, it is more preferable that 5 to 15 volume% acrylic polymer and 2 to 6 volume% cellulose polymer are included.

The cellulosic polymer can contain at least one selected from ethyl cellulose, hydroxy cellulose, and hydroxypropyl cellulose.

Furthermore, the electrode paste contains 1% by volume to 3% by volume of a binder glass that binds the conductive particles to each other, and contains 40% by volume to 60% by volume of a solvent. Moreover, the electrode paste may contain a trace amount photoinitiator.

As the conductive particles, highly conductive silver (Ag) particles, copper (Cu) particles, or the like can be used.

It is more preferable that the organic resin contains 5% by volume to 15% by volume of an acrylic polymer and 2% by volume to 6% by volume of a cellulose polymer. The acrylic polymer can include at least one selected from polybutyl acrylate, polymethacrylate, and the like. The cellulosic polymer can include at least one selected from ethyl cellulose, hydroxy cellulose, and hydroxypropyl cellulose.

As the monomer, acrylonitrile, vinyl acetate, acrylamide, or the like can be used.

The photopolymerization initiator is, for example, one that generates a free radical when exposed to light of a predetermined wavelength at a temperature of 185 ° C. or less, although it is thermally inactive. The photopolymerization initiator includes a substituted or unsubstituted polynuclear quinone which is a compound having two intramolecular rings in a conjugated carbocycle. Examples include 9,10-anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, octamethylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthrenequinone, benzo [a] Anthracene-7,12-dione, 2,3-naphthacene-5,12-dione, 2-methyl-1,4-naphthoquinone, 1,4-dimethylanthraquinone, 2,3-dimethylanthraquinone, 2-phenylanthraquinone, 2 , 3-diphenylanthraquinone, retenquinone, 7,8,9,10-tetrahydronaphthacene-5,12-dione, and 1,2,3,4-tetrahydrobenzo [a] anthracene-7,12-dione .

As the binder glass, at least dibismuth trioxide (Bi ₂ O ₃ ) as a content in the binder glass is 20 to 50% by weight, diboron trioxide (B ₂ O ₃ ) is 5 to 35% by weight, oxidized. It contains 10-20% by weight of zinc (ZnO) and 5-20% by weight of barium oxide (BaO). Further, the binder glass may contain molybdenum trioxide (MoO ₃ ), tungsten trioxide (WO ₃ ), or the like.

Bi ₂ O ₃ is preferably 20 to 50% by weight from the viewpoint that if the content is too large, the thermal expansion coefficient increases and the softening point decreases. Further, it is more preferably 30 to 45% by weight. The content of B ₂ O ₃ forming the glass skeleton is preferably 5 to 35% by weight from the viewpoint that if the content is too large, the coefficient of thermal expansion decreases and the softening point increases. Further, it is more preferably 5 to 30% by weight.

ZnO is preferably 10 to 20% by weight from the viewpoint that if the content is too large, the coefficient of thermal expansion increases and the transparency is impaired.

BaO is preferably 5 to 20% by weight from the viewpoint that if the content is too large, the softening point becomes high.

The average particle size of the glass powder is preferably 4.0 μm or less because it improves the binding property between the electrode and the glass substrate. Further, it is more preferably 1 to 3 μm. Further, the maximum particle size of the glass powder is preferably 10 μm or less because the binding force and the linearity of the electrode end are compatible. Further, it is more preferably 5 to 8 μm.

Examples of the solvent include terpenes such as α-, β-, and γ-terpineol, ethylene glycol monoalkyl ethers, ethylene glycol dialkyl ethers, diethylene glycol monoalkyl ethers, diethylene glycol dialkyl ethers, ethylene glycol monoalkyl ether acetate. , Ethylene glycol dialkyl ether acetates, diethylene glycol monoalkyl ether acetates, diethylene glycol dialkyl ether acetates, propylene glycol monoalkyl ethers, propylene glycol dialkyl ethers, propylene glycol monoalkyl ether acetates, propylene glycol dialkyl ether acetates, Methanol, ethanol, iso Propanol, 1-butanol include such alcohols such as may be used by mixing them each alone or two or more types.

Furthermore, additives such as a dispersant, a plasticizer, a viscosity modifier, an oligomer, a polymer, an ultraviolet absorber, and a sensitizer can be added to the electrode paste.

An electrode paste is produced by mixing and dispersing these materials using a dispersing machine such as a three roll, ball mill or sand mill.

[3-2. Method of forming display electrode pattern]
First, as shown in FIG. 3A, an electrode paste is applied on the front glass substrate 3 by a screen printing method or the like. The electrode paste applied on the front glass substrate 3 forms an electrode paste layer 32. The film thickness of the electrode paste layer 32 is appropriately set in the range of about 10 to 15 μm. Next, the electrode paste layer 32 is dried in a temperature range of 100 ° C. to 200 ° C. Specifically, the solvent, moisture, etc. in the electrode paste layer 32 are removed. As shown in FIG. 3B, the film thickness of the electrode paste layer 32 decreases to about 6 to 9 μm by drying. As a drying means, an infrared drying furnace, an electric furnace or the like is used. The atmosphere for drying may be air or an inert gas.

Next, the electrode paste layer 32 is patterned. First, the electrode paste layer 32 is irradiated with light through a photomask in which a mask pattern of the display electrode 6 is formed of chromium or the like on a glass plate. The wavelength of light is a wavelength at which the photopolymerization initiator contained in the electrode paste layer 32 reacts. Generally, it is about 250 nm to 450 nm. The region irradiated with light in the electrode paste layer 32 is cured by polymerization of the monomer.

Next, the electrode paste layer 32 is developed. As the developer, an alkali developer corresponding to the electrode paste layer 32 is used. Specifically, a sodium carbonate solution, a potassium hydroxide solution, TMAH (tetramethyl anhydride hydroxide), or the like is used. As shown in FIG. 3C, the developer is sprayed onto the electrode paste layer 32, so that the region irradiated with light remains and the region not irradiated with light is removed. That is, the display electrode pattern 34 before firing (unfired) is formed. Finally, water cleaning is performed to remove dirt and the like attached to the front glass substrate 3. Here, binder components such as organic resin remain in the display electrode pattern 34. For convenience of explanation, the thickness of the electrode paste layer 32 in FIGS. 3A, 3B, and 3C is different from the actual product.

[4. Details of Dielectric Layer 8]
In the present embodiment, as described above, the display electrode pattern 34 and the dielectric paste layer 40 are fired simultaneously. However, in the prior art, when the firing process of the display electrode pattern 34 is simply omitted and simultaneous firing is performed, the unfired display electrode pattern 34 is covered with the dielectric paste layer 40. Many binder components such as organic resin remain in the unfired display electrode pattern 34. When the dielectric paste is applied on the display electrode pattern 34, the solvent component contained in the dielectric paste dissolves the binder component remaining in the display electrode pattern 34. Therefore, the Ag component contained in the display electrode pattern is mixed into the dielectric paste layer 40. As a result, after firing, the appearance shape of the display electrode 6 changes greatly, and the sharpness of the image display contour is lost. Furthermore, the dielectric strength characteristics of the dielectric layer 8 are significantly deteriorated.

Therefore, in the present embodiment, by developing a dielectric paste different from the conventional one, the above-mentioned problems are prevented from occurring even if simultaneous firing is performed.

The dielectric layer of the PDP in the present embodiment includes a first glass material and a second glass material for the purpose of effectively reducing the dielectric constant of the dielectric layer, and the dielectric constant is 5 or less. The first glass material includes a plurality of components and has a softening point higher than a firing temperature T (° C.) for forming the dielectric layer. Further, the second glass material has a temperature higher than the T (° C.). Has a low softening point. Here, the first glass material is silicon dioxide (SiO ₂ ), diboron trioxide (B ₂ O ₃ ), alkali metal (potassium oxide (K ₂ O), lithium oxide (Li ₂ O), sodium oxide ( It is desirable to include at least one of Na ₂ O).

Also, the abundance ratio of the first glass material in the dielectric layer 8 is desirably 5% by volume to 30% by volume. When the first glass material in the dielectric layer is lower than 5% by volume, the effect of lowering the dielectric constant of the entire dielectric layer 8 is reduced, and it becomes difficult to achieve a dielectric constant of 5 or less. On the other hand, when the amount of the first glass material is 30% by volume or more, a region where the first glass material is present in the dielectric layer 8 is increased, resulting in a problem that the bonding force as the dielectric layer is weakened.

As shown in FIG. 2, the dielectric layer 8 includes a first glass material 20 and a second glass material 21 to be a glass layer. As will be described later, since the softening point of the first glass material is higher than the firing temperature at which the dielectric layer 8 is formed, the first glass material and the second glass material are not in a completely solid solution form. Further, for convenience of explanation, the size and number of the first glass material 20 shown in FIG. 2 are different from actual products.

In addition, conventionally, the dielectric glass contained 20% by weight or more of lead oxide in order to lower the softening point. However, in this embodiment, the dielectric glass does not contain lead oxide for environmental consideration. That is, the dielectric layer 8 does not contain lead oxide.

[4-1. Production of dielectric paste]
The dielectric paste for forming the dielectric layer includes a first glass material powder, a second glass material powder, and binder components such as a vehicle and a solvent.

[4-1-1. First glass material powder]
In the present embodiment, the powder of the first glass material is a glass material whose softening point is higher than the firing temperature T (° C.) of the dielectric layer 8 described later, and the glass material having a plurality of components is pulverized. The glass material powder.

Here, the reason for using the powder glass material obtained by pulverizing the powder of the first glass material will be described. As a method for producing a glass powder material, there are a melt pulverization method for pulverizing molten glass, and a chemical synthesis method such as a precipitation method and a gel method. The chemical synthesis method is very effective for preparing the above-described SiO ₂ filler particles (silica particles) as a powder. However, in the chemical synthesis method, it is very difficult to prepare by adjusting the desired composition and concentration.

For example, a powder containing diboron trioxide (B ₂ O ₃ ) can be prepared by a chemical synthesis method, but it is difficult to adjust the concentration appropriately. As for the alkali metal (R 2 _O), it is very difficult itself to create the added silica particles.

On the other hand, the melt pulverization method can be prepared by adjusting various compositions and concentrations as desired.

Therefore, in the present embodiment, the powder of the first glass material, which is a glass material having a high softening point and containing a plurality of components, is prepared by the melt pulverization method as described above.

The first glass material is silicon dioxide (SiO ₂ ), diboron trioxide (B ₂ O ₃ ), and alkali metals such as potassium oxide (K ₂ O), lithium oxide (Li ₂ O), and sodium oxide (Na ₂ O) is included.

Besides these, zinc oxide (ZnO), magnesium oxide (MgO), calcium oxide (CaO), and the like may also be included. The component ratio of the first glass material is adjusted so that the softening point is higher than the firing temperature T (° C.) of the dielectric layer 8. In the present embodiment, the softening point of the first glass material is 700 ° C. or higher.

Next, the dielectric glass material having the exemplified composition components is pulverized by a wet jet mill, a ball mill, or the like so that the average particle size becomes 0.5 μm to 3.0 μm. As described above, the powder of the first glass material is produced.

[4-1-2. Second glass material powder]
Examples of the powder of the second glass material include diboron trioxide (B ₂ O ₃ ), silicon dioxide (SiO ₂ ), potassium oxide (K ₂ O) which is an oxide of an alkali metal, and lithium oxide (Li ₂ O). ) And sodium oxide (Na ₂ O).

Also, as described above, the dielectric glass fine particles may contain zinc oxide (ZnO), magnesium oxide (MgO), calcium oxide (CaO), etc. in addition to the main component. The component ratio of the second glass material is adjusted so that the softening point is lower than the firing temperature T (° C.) of the dielectric layer 8. In the present embodiment, the softening point of the second glass material is 600 ° C. or less.

Next, the dielectric glass material having the exemplified composition components is pulverized by a wet jet mill, a ball mill, or the like so that the average particle size becomes 0.5 μm to 3.0 μm. As described above, the powder of the second glass material is produced.

[4-1-3. Dielectric paste]
A dielectric paste is produced by kneading the dielectric glass material and the binder component. A three roll or the like is used for kneading. The dielectric paste is used for a die coating method or a printing method. The dielectric glass material includes a first glass material and a second glass material.

The binder component contains terpineol or butyl carbitol acetate containing 1% to 20% by weight of ethyl cellulose or acrylic resin, and a solvent. To the dielectric paste, dioctyl phthalate, dibutyl phthalate, triphenyl phosphate, tributyl phosphate and the like may be added as a plasticizer. To the dielectric paste, glycerol monooleate, sorbitan sesquioleate, homogenol (product name of Kao Corporation), phosphate ester of alkylallyl group, or the like may be added as a dispersant. This is because the printability of the dielectric paste is improved. The binder component may be combined with a solvent used for pulverizing the first glass material or the second glass material.

The solvent for the dielectric paste according to this embodiment will be described. The solvent includes a first solvent and a second solvent. The first solvent is a solvent containing neither a double bond nor an OH group. The second solvent is a terpene solvent. For example, it is desirable that the solvent containing neither a double bond nor an OH group is dihydroterpinyl acetate. The terpene solvent is preferably terpineol, terpinyl acetate, or dihydroterpineol. These chemical formulas are shown in FIGS. 4A, 4B, 4C, and 4D.

The reason why these solvents are selected will be explained. First, the reason why a double bond is not included will be explained. The unsintered display electrode pattern includes a binder component. For this reason, when a solvent or the like containing a double bond touches the display electrode pattern, the solvent dissolves the binder component.

The binder component dissolved in the dielectric paste may form void defects after simultaneous firing. Further, the Ag component contained in the display electrode 6 may be mixed into the dielectric layer 8 in some cases. Therefore, it becomes a factor that significantly reduces the dielectric strength characteristics of the dielectric layer 8.

For this reason, the solvent of the dielectric paste according to the present embodiment has dihydroterpinyl acetate that does not contain a double bond. Therefore, dissolution of the binder component contained in the display electrode pattern is suppressed.

Next, the reason why the OH group is not included will be explained. When the display electrode pattern as described above is formed, water cleaning is performed.

The display electrode pattern absorbs moisture by washing with water. Conventionally, a baking process has been performed after the development process and before the application of the dielectric paste. Therefore, the moisture absorbed in the display electrode pattern has evaporated. That is, no moisture remained when applying the dielectric paste. However, in this embodiment, the dielectric paste is applied before firing the display electrode pattern. The inventors have found that when the solvent contained in the dielectric paste contains a lot of OH groups, the moisture absorbed in the display electrode pattern 34 oozes out to the dielectric paste side covering the display electrode pattern 34. I found. The exuded moisture causes cracks and dents in the dielectric layer 8 after firing the dielectric paste, and causes a decrease in the dielectric strength characteristics of the dielectric layer 8.

In contrast, in the present embodiment, the solvent of the dielectric paste has dihydroterpinyl acetate that does not contain OH groups. For this reason, the above exudation is suppressed.

For the above two reasons, in this embodiment, the solvent of the dielectric paste contains dihydroterpinyl acetate at 40% by weight or more based on the total amount of the solvent of the dielectric paste. More desirably, it is 50% by weight or more. Thereby, the effect which suppresses melt | dissolution of the binder component contained in a display electrode pattern is acquired.

The reason why terpene solvents are used is explained. Examples of terpene solvents include α-pinene (boiling point: 156 ° C), β-pinene (boiling point: 161 ° C), limonene (boiling point: 177 ° C), terpineol (boiling point: 209 ° C), and terpinyl acetate. (Boiling point: 220 ° C.), dihydroterpineol (boiling point: 207 ° C.), dihydroterpinyl acetate (boiling point: 220 ° C.), and the like.

As described above, it is very effective to contain dihydroterpinyl acetate in order to suppress the dissolution of the binder component of the display electrode pattern 34 and the phenomenon of moisture exudation. On the other hand, dihydroterpinyl acetate is poorly soluble in components such as ethyl cellulose or acrylic resin contained in the dielectric paste. That is, the dielectric paste containing dihydroterpinyl acetate has a disadvantage that the dispersibility is poor.

When the dispersibility of the dielectric paste is inferior, especially when the unfired display electrode pattern 34 and the dielectric paste layer 40 are fired simultaneously, the display electrode pattern 34 shrinks during firing. That is, the dielectric paste layer 40 cannot follow the behavior of the display electrode pattern 34. As a result, cracks and the like occur in the dielectric layer 8 after firing. Cracks also cause a significant decrease in the dielectric strength characteristics of the dielectric layer 8.

Therefore, in order to make up for such drawbacks, in the present embodiment, a terpene solvent having an OH group is contained in the dielectric paste solvent in an amount of 1% by weight to 5% by weight with respect to the total amount of the dielectric paste. ing. When the content is lower than 1% by weight, the effect of preventing the cracking phenomenon of the dielectric layer cannot be obtained. When the content is more than 5% by weight, the effect of suppressing the seepage of moisture from the display electrode pattern 34 is insufficient due to the influence of OH groups.

[4-2. Method for Forming Dielectric Layer 8]
As a method for forming the dielectric layer 8, a screen printing method, a die coating method, or the like is used. First, as shown in FIG. 3D, a dielectric paste is applied on the front glass substrate 3 on which the display electrode pattern 34 is formed so as to cover the display electrode pattern 34. The applied dielectric paste forms a dielectric paste layer 40. The film thickness of the dielectric paste layer 40 is appropriately set in consideration of the rate of shrinkage due to firing.

Next, the dielectric paste layer 40 is dried in a temperature range of 100 ° C. to 200 ° C. As shown in FIG. 3E, the film thickness of the dielectric paste layer 40 is reduced by drying. As a drying means, an infrared drying furnace, an electric furnace or the like is used. Air or an inert gas is used as an atmosphere for drying.

Next, the display electrode pattern 34 and the dielectric paste layer 40 are fired simultaneously. The firing temperature is in the temperature range of 450 ° C to 650 ° C. More preferably, the temperature range is 550 ° C to 600 ° C. Here, in the present embodiment, the firing temperature is set lower than the softening point of the first glass material and higher than the softening point of the second glass material. Thereby, the display electrode 6, the light shielding layer 7, and the dielectric layer 8 made of the first glass material 20 and the second glass material 21 are formed.

Note that the luminance of the PDP 1 is improved as the thickness of the dielectric layer 8 is reduced. Further, the discharge voltage of the PDP 1 decreases as the thickness of the dielectric layer 8 decreases. Therefore, it is preferable that the thickness of the dielectric layer 8 is as small as possible within a range where the withstand voltage does not decrease. In the present embodiment, as an example, the film thickness of the dielectric layer 8 is not less than 10 μm and not more than 30 μm from both the viewpoint of dielectric strength and the viewpoint of visible light transmittance.

[5. Example]
The PDP according to the embodiment was produced. The discharge cell is sized to fit a 42-inch class high-definition television. The height of the partition walls is 0.15 mm, the distance between the partition walls (cell pitch) is 0.15 mm, and the distance between the display electrodes is 0.06 mm. A Ne—Xe-based mixed gas having a Xe content of 15% by volume was sealed at 60 kPa. The thickness of the front glass substrate and the back glass substrate is 1.8 mm. The film thickness of the dielectric layer is 20 μm.

In the examples, electrode pastes having the compositions shown in Table 1 were produced.

As shown in Table 1, Sample A includes 21% by volume of silver particles, 10% by volume to 25% by volume of an organic resin, and 10% by volume to 20% by volume of a monomer. The organic resin has an acrylic polymer and a cellulose polymer. The polybutyl acrylate which is an acrylic polymer is 5 volume% or more and 15 volume% or less. Ethyl cellulose, which is a cellulose polymer, is 2% by volume or more and 10% by volume or less. Furthermore, the sample A contains the above-mentioned solvent, monomer, and binder glass. Furthermore, the sample A contains a trace amount photoinitiator.

Sample B includes 20% by volume of silver particles, 19% by volume or less of an organic resin, and 24% by volume or less of a monomer. The organic resin has only an acrylic polymer. Polybutyl acrylate was used as the acrylic polymer. Further, the sample B includes the same solvent, monomer, and binder glass as the sample A. Furthermore, the sample B contains a trace amount photoinitiator.

In the examples, a dielectric paste having the composition shown in Table 2 was produced.

The amount of solvent described in Table 2 is a weight fraction with respect to the total amount of solvent. Diethylene glycol monobutyl ether acetate was used as the other solvent in Table 2.

A PDP was produced using these electrode pastes and dielectric paste, and simultaneously firing the electrodes and dielectric layers. The parameters of the electrode paste are two levels, sample A and sample B. The parameters of the dielectric paste are 8 levels from Sample 1 to Sample 8. PDPs were produced with all combinations of electrode paste and dielectric paste. That is, 16 types of PDPs were produced.

The coating thickness of the electrode paste was adjusted to 12 μm. The film thickness of the display electrode pattern after drying was 6 μm when formed from Sample A. On the other hand, the film thickness of the display electrode pattern after drying was 7 μm when formed from Sample B.

In all PDPs using Sample B as the electrode paste, voids were observed between the display electrode and the dielectric layer. That is, a non-defective product was not obtained with the PDP using the sample B. This is because the film thickness of the display electrode pattern formed from Sample B is relatively thick and contracts from the dielectric paste layer during simultaneous firing.

On the other hand, all the PDPs using Sample A as the electrode paste had no gap between the display electrode and the dielectric layer. The film thickness of the display electrode pattern formed from the sample A is thinner than the film thickness of the display electrode pattern formed from the sample B. In other words, this is because the shrinkage of the display electrode pattern is suppressed more than the shrinkage of the display electrode pattern formed from the sample B.

In order to compare the characteristics of PDPs using Sample A as the electrode paste and Samples 1 to 8 as the dielectric paste, the dielectric strength characteristics of the dielectric layers were evaluated. In order to evaluate the dielectric strength characteristics, a voltage of 500 V was applied between the address electrode and the sustain electrode, and the number of dielectric breakdowns at that time was measured. The results are shown in Table 2. The dispersibility of the dielectric paste, the presence or absence of the bleeding phenomenon, and the presence or absence of dissolution of binder components such as display electrodes were also evaluated.

As shown in Table 2, the number of dielectric breakdowns is reduced by containing dihydroterpinyl acetate having no double bond or OH group and terpene solvent such as terpineol, terpinyl acetate, or dihydroterpineol. I understand that.

Particularly, dihydroterpinel acetate having no double bond or OH group is 50% by weight or more based on the total solvent, and terpeneol, terpinyl acetate, or dihydroterpineol, which is a terpene solvent, is 1% by weight or more. In Sample 1 and Sample 2 of 5% by weight or less, the bleeding phenomenon and the dissolution phenomenon of the binder component such as the display electrode were sufficiently suppressed, and the dispersibility of the dielectric paste was also good.

As described above, the present embodiment realizes a PDP electrode paste and a PDP manufacturing method capable of significantly reducing production costs while maintaining high quality and high reliability of the PDP.

As described above, the technology disclosed in the present embodiment realizes a low power consumption PDP and is useful for a large screen display device.

1 PDP
2 Front plate 3 Front glass substrate 4

Scan electrode

4a,

5a Black electrode

4b, 5b White electrode 5 Maintenance electrode 6 Display electrode 7 Black stripe (light shielding layer)
DESCRIPTION OF SYMBOLS 8 Dielectric layer 9 Protective layer 10 Back plate 11 Back glass substrate 12 Address electrode 13 Base dielectric layer 14 Partition 15 Phosphor layer 16 Discharge space 20 First glass material 21 Second glass material 32 Electrode paste layer 34 Display electrode pattern 40 Dielectric paste layer

Claims

15% by volume or more and 25% by volume or less of conductive particles;
10% to 25% by volume of organic resin;
10 volume% or more and 20 volume% or less of monomer,
The organic resin includes an acrylic polymer and a cellulose polymer,
Electrode paste for plasma display panels.
2. The electrode paste for a plasma display panel according to claim 1, wherein the organic resin contains 5% by volume to 15% by volume of an acrylic polymer and 2% by volume to 10% by volume of a cellulose polymer.
2. The electrode paste for a plasma display panel according to claim 1, wherein the organic resin includes 5% by volume to 15% by volume of an acrylic polymer and 2% by volume to 6% by volume of a cellulose polymer.
The cellulosic polymer includes at least one selected from ethyl cellulose, hydroxy cellulose, and hydroxypropyl cellulose.
The electrode paste for plasma display panels of Claim 1.
An electrode paste layer is formed by applying the electrode paste for a plasma display panel according to claim 1 to a substrate,
Next, by shaping the electrode paste layer, an electrode pattern in which at least the organic resin remains is formed,
Next, a dielectric paste layer that covers the electrode pattern is formed by applying a dielectric paste to the substrate,
Next, the electrode pattern and the dielectric paste layer are simultaneously fired to form an electrode and a dielectric layer.
A method for manufacturing a plasma display panel.
The dielectric paste comprises a dielectric glass and a solvent,
The solvent includes a first solvent and a second solvent,
The first solvent has neither a double bond nor a hydroxyl group,
The second solvent includes a terpene solvent.
The manufacturing method of the plasma display panel of Claim 5.
The first solvent has a content of 40 wt% or more and 99 wt% or less with respect to the total amount of the solvent of the dielectric paste,
The second solvent has a content of 1 wt% or more and 5 wt% or less with respect to the total amount of the solvent of the dielectric paste.
The manufacturing method of the plasma display panel of Claim 6.
The first solvent is dihydroterpinyl acetate;
The second solvent includes at least one selected from terpineol, terpinyl acetate, and dihydroterpineol.
The manufacturing method of the plasma display panel of Claim 7.