JPH1012150A - Ac plasma display panel and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an AC PDP(plasma display panel) and its manufacturing process, in which a baking process is eliminated to simplify the process, energy is saved, cost is reduced, traditional technical problems and solved, and a practically sufficient memory margin is obtained. SOLUTION: In a PDP in which a back substrate 2 and a front substrate 1 are faced so that a gas discharge space is interposed between them, electrode 4a, 4b covered with a dielectric layer 5 are formed at least one substrate, and a protection layer 6 is formed on the dielectric layer 5, the dielectric layer 5 and the protection layer 6 are formed at the same time by the heat treatment of a covering film comprising a dielectric layer forming coating solution and a covering film comprising a protection film forming coating solution formed on the covering film for forming the dielectric layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC PDP and a method of manufacturing the same, and more particularly, to an AC PDP characterized by the structure of a dielectric layer and a protective layer of the AC PDP and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a so-called PDP that uses a light emission phenomenon caused by discharge for a display has an electrode (mainly an I-type).
The TO) structure is roughly classified into a DC type in which a metal electrode is exposed in a discharge space and an AC type in which a metal electrode is covered with a dielectric layer. In particular, when used for a thin and large-screen color television, an AC PDP having a memory function and capable of responding to an increase in size is preferable. This AC type PDP is
The electrode structure is classified into a surface discharge method and a counter electrode method. In either method, a protective layer (film) mainly made of magnesium oxide is formed on the surface of the dielectric layer.

In an AC type PDP, a dielectric layer and its protective layer are formed, for example, by (1) printing a glass paste on a chromium electrode formed on a glass substrate by a vacuum evaporation method, and drying and firing (580 ° C.). To form a dielectric layer (film)
Next, (2) a magnesium oxide-containing printing paste is applied on the dielectric layer, dried and fired (400 ° C.) to form a magnesium oxide layer (film).

[0004]

In the above method, a total of two firing steps are required to form the dielectric layer and its protective layer, which complicates the process and hinders continuous production. ing. Further, it is not preferable from the viewpoint of energy saving. Further, in this method, the adhesion between the protective layer and the dielectric layer may be insufficient, or the protective layer may be cracked in the course of firing.

Accordingly, an object of the present invention is to reduce the number of firing steps in the prior art, simplify the steps, contribute to energy saving and cost reduction, and provide an AC type PDP having a practically sufficient memory margin width and its manufacturing. Is to provide a way.

[0006]

The above object is achieved by the present invention described below. That is, according to the present invention, the back substrate and the front substrate are arranged to face each other with the gas discharge space interposed therebetween, and at least one of the substrates is provided with an electrode covered with a dielectric layer,
In an AC type PDP in which a protective layer is formed on a dielectric layer, the dielectric layer and the protective layer are formed of a coating composed of a dielectric layer forming coating solution and a protective layer forming coating formed thereon. An alternating current type PDP characterized by being formed by simultaneously heating a film made of a working liquid, and a method for producing the same.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in further detail with reference to the embodiments shown in the drawings. FIG. 1 is a diagram showing a schematic structure of a surface discharge type AC PDP according to a preferred embodiment of the present invention. In FIG. 1, an AC type PDP is composed of a front substrate 1 and a rear substrate 2 which are opposed to each other in parallel with a gas discharge space 3 interposed therebetween, and the substrates 1 and 2 are formed of glass plates having a predetermined thickness. .

On the surface of the front substrate 1 facing the rear substrate 2, an electrode pair 4 composed of an X electrode 4a and a Y electrode 4b is formed. The electrode pair 4 is covered with, for example, a dielectric layer 5 made of glass. Further, the dielectric layer 5 is covered with a protective layer 6 made of, for example, magnesium oxide. On the surface of the rear substrate 2 facing the front substrate 1, an address electrode 7, a barrier 8 and a phosphor layer 9 are formed. Further, a titanium dioxide film (high-refractive-index layer) 10 and a silicon dioxide film (low-refractive-index layer) 11, for example, are formed on the front substrate 1 as antireflection layers as required.

FIG. 2 is a diagram showing a schematic structure of an opposed-discharge type AC PDP according to a preferred embodiment of the present invention. In FIG. 2, an X electrode 4a is formed on the surface of the front substrate 1 facing the rear substrate 2, and the X electrode 4a is covered with, for example, a dielectric layer 5 made of glass. The layer is covered with a protective layer 6 made of, for example, magnesium oxide. On the surface of the back substrate 2 facing the front substrate 1, a Y electrode 4b, a dielectric layer 5 similar to the above,
The protective layer 6, the barrier 8, and the phosphor layer 9 are formed.
Further, a titanium dioxide film (high-refractive-index layer) 10 and a silicon dioxide film (low-refractive-index layer) 11, for example, are formed on the front substrate 1 as antireflection layers as required.

Next, the structure of the dielectric layer and the protective layer of the AC PDP of the present invention, which mainly characterizes the present invention, will be described. (1) Formation of Coating Film Made of Coating Solution for Forming Dielectric Layer First, a coating solution for forming a dielectric layer is formed on electrodes formed on at least one of the front substrate 1 and the rear substrate 2 shown in FIGS. To form a coating. The coating liquid for forming a dielectric layer is used as a paste by mixing dielectric particles such as low-melting glass, silicon dioxide, lead oxide, and silicon nitride with, for example, a binder and a solvent. Needless to say, the form may be other than paste. The preferred particle size of these dielectric particles is 0.01 to
1.0 μm, more preferably 0.05 to 0.5 μm
m.

[0011] For example, when the paste-like coating liquid is used, the coating comprising the dielectric layer forming coating liquid is formed by screen-printing and drying the coating liquid on the electrode. You. The thickness of the coating after drying is usually 5 to 5
It is about 0 μm. When the coating liquid is a liquid such as a dispersion, a normal coating method such as spray coating, dip coating, spin coating, roll coating, bar coating, meniscus coating, curtain flow coating, etc. Is used.

(2) Formation of a coating composed of a coating liquid for forming a protective layer Next, a coating is formed on the coating composed of the coating liquid for forming a dielectric layer by using the coating liquid for forming a protective layer. Form. The coating liquid for forming the protective layer may be one containing an alkaline earth metal compound alone, or may be made of particles of lead oxide, silicon dioxide, silicon nitride, or the like, or the surface of a low-melting glass particle forming a dielectric layer. It may contain inorganic composite particles coated with an alkaline earth metal compound. With respect to the form of the coating liquid, for example, it is used as a paste, a dispersion liquid (sol solution) or the like, but any form may be used.

When the coating liquid for forming a protective layer contains only an alkaline earth metal compound, the alkaline earth metal compound particles preferably have a particle size of 0.01 to 1.0 μm, more preferably 0 to 1.0 μm. 0.05 to 0.5 μm. When the particle size is less than 0.01 μm, the formed protective layer cannot exhibit a sufficient protective function.
If it exceeds μm, the transparency and visibility of the formed protective layer will be impaired. A preferred alkaline earth metal is magnesium, and preferred magnesium compounds include, for example, inorganic compounds such as magnesium oxide, magnesium hydroxide, and magnesium carbonate; And organic magnesium compounds having a group. When using an organic magnesium compound having a hydrolyzable group as a dispersion of water or an organic solvent, use additives such as alkanolamines such as diethanolamine, carboxylic acids, and glycols that promote dispersion stability. Is preferred.

When the coating liquid for forming a protective layer is the inorganic composite particles, the particle size of the alkaline earth metal compound covering the inorganic particles is preferably 0.001 to 0.5 μm. Preferably it is 0.01 to 0.1 μm. When the particle size is less than 0.001 μm, the super-particles of the alkaline earth metal compound form aggregates, so that the coating treatment with the alkaline earth metal compound at the time of forming the composite particles is extremely difficult, and uniform coating is performed. Can not be obtained. On the other hand, when the particle size exceeds 0.5 μm, the coating treatment of the inorganic particles with the alkaline earth metal compound cannot be performed efficiently.

The above-mentioned inorganic composite particles are prepared by a mechanical method using a powder mixer or the like; low-melting glass particles or the like are dispersed in a solution of an alkaline earth metal compound, and a derivative of the alkaline earth metal compound is dispersed on the surface of the particles. Precipitation method; + and-respectively
A method utilizing hetero-aggregation in which fine particles having a zeta potential of 1 are mixed in a medium to aggregate the other particles on the surface of one particle (for example, the zeta potential of low melting glass particles is -1
5.76V, the zeta potential of magnesium oxide is +30.
18V); a surface decoration method in which inorganic particles having mutually reactive groups and an alkaline earth metal compound (solution state) are reacted to form a coating of a derivative of an alkaline earth metal compound on the surface of the inorganic particles ( For example, an organic alkaline earth metal compound having a hydrolyzable group is dissolved and reacted in a dispersion of inorganic particles having an OH group on the surface).

A coating composed of the coating liquid for forming a protective layer is formed on the coating composed of the coating liquid for forming a dielectric layer formed in the above (1). The method of forming the coating film composed of the coating liquid for forming the protective layer is exactly the same as in the case of (1). The thickness of the coating after drying is usually about 0.01 to 10 μm. In particular, when a coating liquid containing the above composite particles is used, a single coating forms a laminated film having the functions of the dielectric layer and the protective layer, which is advantageous in cost. In the case where the outermost protective layer is to be formed, the protective layer must be a dense film made of ultrafine particles (having a particle size of 0.1 μm or less) in order to have a sufficient function as the protective layer. Although most preferred, it is difficult to obtain a uniform dispersion of ultrafine particles of an alkaline earth metal compound as described above because the ultrafine particles have a very strong cohesive force. On the other hand, if the surface of the inorganic particles for forming the dielectric layer having a relatively large particle diameter is coated with the ultrafine particles of the alkaline earth metal compound, the problem of aggregation of the ultrafine particles is caused. Does not occur, and a uniform coating liquid in which the alkaline earth metal compound is in the form of ultrafine particles is obtained, and the coating liquid can form a protective layer having a uniform and dense structure.

In the present invention, when a coating is formed by applying a coating liquid for forming a protective layer in a liquid state such as a dispersion liquid on a coating made of a coating liquid for forming a dielectric layer, a protective coating is formed. The coating liquid for forming a layer penetrates into the inside of the coating made of the coating liquid for forming a dielectric layer, and the coating liquid for forming a protective layer may be buried in the dielectric layer after firing, or may be buried in the dielectric layer. In some cases, the coating liquid for forming a protective layer aggregates on the coating made of the coating liquid for forming, so that a uniform coating cannot be obtained. In such a case, by forming a layer made of a polymer material and then forming a film made of a coating liquid for forming a protective layer on the film made of a coating liquid for forming a dielectric layer, It is possible to form a uniform coating of the protective layer forming coating solution without any problem. The polymer material is not particularly limited,
A material that is water-soluble and completely decomposed by firing and does not leave any organic matter in the film, for example, celluloses, acrylic resin,
Acetal resins are preferred materials. The polymer material is applied as a solution to the coating made of the coating liquid for forming a dielectric layer by the above-mentioned coating method, and dried. The thickness of the layer made of a polymer material is not particularly limited as long as the above problem is prevented, and is not particularly limited.
It is about.

(3) Formation of Dielectric Layer and Protective Layer Thereof The coating made of the coating liquid for forming a dielectric layer in the above (1) and (2), and the coating for forming a protective layer formed thereon. By heating (baking) the front and / or back substrate on which the liquid film is laminated, a dielectric layer having a predetermined thickness and a protective layer thereof are formed. The firing is performed at the temperature and time for forming a normal dielectric layer. For example, it is about 1 to 4 hours at 400 to 600 ° C. By heating in the above procedure, an intermediate layer in which the dielectric layer forming material and the protective layer forming material are mixed is partially formed. Therefore, sufficient adhesion between the dielectric layer and the protective layer becomes possible,
The film strength of the protective layer is sufficiently improved.

As described above, the AC-type PDP of the present invention is obtained by laminating the front substrate and the rear substrate each having the dielectric layer and the protective layer formed on at least one substrate and enclosing the penning gas in the space. Is manufactured.

[0020]

Next, the present invention will be described more specifically with reference to examples. The parts and percentages in the text are based on weight unless otherwise specified. Example 1 Preparation of Coating Solution for Protective Layer Formation Magnesium oxide (UBE Kosan, UBE
2000A) was dispersed to prepare a 2% concentration magnesium oxide dispersion.

The surface discharge AC PDP shown in FIG. 1 was produced as follows. A chromium electrode (X electrode 4a and Y electrode) having a thickness of 0.2 μm was formed on a glass substrate serving as a front substrate by a vacuum evaporation method.
An electrode 4b) is formed, and a paste obtained by dispersing a low-melting glass in an aqueous solution of hydroxypropylmethylcellulose as a coating liquid for forming a dielectric layer is coated thereon with a dry film thickness of 20 μm.
m.

Next, the above-mentioned coating liquid for forming a protective layer is coated on the coating formed of the coating liquid for forming a dielectric layer by dip coating such that the dry film thickness becomes approximately 0.2 μm. , And dried at 120 ° C. for 0.5 hour. Then 580 ° C
For 2 hours. The total thickness of the dielectric layer 5 and the protective layer 6 thus formed was 15 μm.

On the other hand, a 0.2 μm thick address electrode 7 is formed by patterning a chromium electrode formed on a glass substrate serving as a rear substrate by a vacuum evaporation method, and then a 150 μm thick screen electrode is formed on the address electrode 7 by screen printing. Barrier 8 is formed, and a fluorescent substance having a thickness of 10
The phosphor layer 9 was formed by coating to a thickness of μm.

The two substrates obtained above are bonded together with their processing surfaces facing each other, and He-Xe (1.1%)
The alternating current type PDP of the present invention was manufactured by enclosing Penning gas at 500 Torr. With respect to this PDP, a discharge starting voltage (Vf) and a minimum sustaining voltage (Vsm) were measured using a pulse having a driving waveform of a driving frequency of 15 KHz and a duty ratio of 23%.

The measurement results are as follows: Vf = 190 V, Vsm = 1
60V, Vf-Vsm (memory margin) = 30V. When these values are compared with a panel having the same structure using a vacuum deposited film instead of the magnesium oxide film, Vf was higher by about 30 V and Vsm was higher by about 55 V. However, practically, the memory margin has a sufficient width of 30 V, and it has been confirmed that the magnesium oxide film formed by the above method exhibits sufficient characteristics as a protective layer.

Example 2 A 1% aqueous solution of hydroxypropylmethylcellulose was applied by dip coating on a coating made of a coating solution for forming a dielectric layer, and dried at 120 ° C. for 30 minutes. An AC-type PDP of the present invention was produced in the same manner as in Example 1 except that a film made of a working solution was formed.
The discharge start voltage (Vf) and the minimum sustain voltage (Vsm) were measured, and the same results as in Example 1 were obtained.

Example 3 Preparation of Coating Liquid for Protective Layer Formation Magnesium acetate was added to 128.43 parts of a liquid (solid content: 1%) in which low-melting glass powder (particle diameter: 2 to 3 μm) was dispersed in special grade ethanol. 14.27 parts of tetrahydrate were dissolved. This solution was refluxed at 80 ° C. for 1 hour to precipitate a magnesium compound on the surface of the lead oxide. The powder was separated from this solution by filtration and dried at room temperature for 12 hours. One part of the obtained powder (inorganic composite particles) was dispersed in 49 parts of a 0.25% aqueous solution of hydroxypropylmethylcellulose to obtain a coating liquid for forming a protective layer.

The same procedure as in Example 1 was carried out except that the above coating liquid was used as the coating liquid for forming the protective layer.
DP was prepared. The discharge start voltage (Vf) and the minimum sustain voltage (Vsm) were measured, and the same results as in Example 1 were obtained.

[0029]

According to the present invention described above, the dielectric layer and its protective layer can be formed in one firing step.
It is possible to reduce the production cost of PDP and save energy. In addition, since a coating method can be used to form each layer, a large-screen PDP can be manufactured at low cost. Further, by forming a protective layer forming film on the dielectric layer forming film and performing heat treatment at the same time, an intermediate layer in which the dielectric layer forming material and the protective layer forming material are mixed is partially formed. Therefore, the adhesion between the dielectric layer and the protective layer is sufficient, and the film strength of the protective layer is sufficiently improved. Further, the AC type PDP of the present invention has a sufficient memory margin width, and thus is suitable as a large PDP for a color television.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a schematic structure of a surface discharge type AC PDP of the present invention.

FIG. 2 is a cross-sectional view showing a schematic structure of an AC-type PDP of the opposed discharge type according to the present invention.

[Explanation of symbols]

 1: Front substrate 2: Back substrate 3: Discharge space 4: Counter electrode 4a: X electrode 4b: Y electrode 5: Dielectric layer 6: Protective layer 7: Address electrode 8: Phosphor 9: Barrier 10: Titanium dioxide film ( High refractive index layer) 11: Silicon dioxide film (Low refractive index layer)

Claims (8)

[Claims] 1. A back substrate and a front substrate are opposed to each other with a gas discharge space interposed therebetween. At least one of the substrates has an electrode covered with a dielectric layer, and a protective layer is formed on the dielectric layer. In the AC type plasma display panel (hereinafter simply referred to as PDP), the dielectric layer and the protective layer are formed from a coating composed of a dielectric layer forming coating liquid and a protective layer forming coating liquid formed thereon. An AC-type PDP characterized by being formed by heat-treating a coating film simultaneously. 2. A layer comprising a polymer material between a coating comprising a coating liquid for forming a dielectric layer and a coating comprising a coating liquid for forming a protective layer. The AC PDP according to claim 1, wherein a layer and a protective layer are formed. 3. The alternating current type PD according to claim 1, wherein the coating liquid for forming a protective layer contains an alkaline earth metal compound.
P. 4. The coating solution for forming a protective layer contains inorganic composite particles coated with an alkaline earth metal compound.
Or the alternating-current PDP according to 2. 5. The alkaline earth metal compound is an alkaline earth metal oxide, hydroxide, carbonate or an organic alkaline earth metal compound having a hydrolyzable group.
Or the AC type PDP according to 4. 6. A back substrate and a front substrate are arranged opposite to each other with a gas discharge space interposed therebetween, and at least one substrate is provided with an electrode covered with a dielectric layer, and a protective layer is formed on the dielectric layer. In the production of the AC type PDP to be formed, a coating liquid is formed by applying a coating liquid for forming a dielectric layer on the electrode,
Further, an alternating current type PDP is characterized in that a coating liquid for forming a protective layer is applied on this film to form a film, and then both films are heat-treated simultaneously to form a dielectric layer and a protective layer.
Manufacturing method. 7. After forming a coating composed of a coating liquid for forming a dielectric layer, and before forming a coating composed of a coating liquid for forming a protective layer, on the coating formed of the coating liquid for forming a dielectric layer. 7. The AC type PD according to claim 6, wherein a layer made of a polymer material is formed.
Method for producing P. 8. The method for producing an AC type PDP according to claim 6, wherein the coating liquid for forming a protective layer is the coating liquid according to any one of claims 3 to 5.