JPH11213900A - Plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the crackings or distortion in a protecting layer and the coloring by the use of an AG bus electrode by setting the DTA transition temperature of a dielectric layer higher than the sealing temperature for sealing a front plate to a back plate with a sealing material. SOLUTION: An AC-type PDP front plate is manufactured by providing a transparent electrode 4, a metal electrode 5, a dielectric layer 2, a sealing layer, and a protective layer 3 on a substrate in this order. The front plate and a back plate obtained in different processes are stuck together and sealed in a sealing process. Namely, both the plates are positioned, heated in a baking furnace to have the material of the seal layer fuse, and fixed. At this time, the material of the dielectric layer 2 is regulated so that the DTA transition temperature is higher than the sealing temperature of the sealing process. More specifically, as the material of the dielectric layer 2, various low melting point glasses having DTA transition temperature of 375-417 deg.C are selected, and when a low-melting point glass with a DTA transition temperature of 417 deg.C is used, for example, sealing is made at a sealing temperature of about 410 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention belongs to the technical field of a plasma display panel. In particular, with respect to a dielectric layer formed on a front plate of an AC surface discharge type plasma display panel, to avoid a problem caused by distortion of the dielectric layer when the front plate and the back plate are sealed with a sealing material. The present invention relates to a plasma display panel that can be used.

[0002]

2. Description of the Related Art An AC surface discharge type plasma display panel for performing color display (hereinafter referred to simply as "AC type PD").
P) is used, a plurality of partitions are formed in parallel on the back plate. A fluorescent screen is provided on the address electrode between the partitions. The phosphor screen between each partition is R
One of the phosphor materials that emits light of each of the RGB colors is filled, and the back plate has a structure in which a large number of sets of three striped phosphor screens of each of the RGB colors are arranged. Figure 4 shows an AC type PDP
In this figure, a front plate and a back plate are separated from each other, and two glass substrates 101 and 102 are arranged in parallel and opposed to each other. Are held at regular intervals by partition walls 103 provided in parallel on a glass substrate 102 to be formed. A pair of transparent electrodes (display electrodes) 104a and 104b are provided on the back plate side of the glass substrate 101 serving as the front plate as discharge sustaining electrodes.
And a pair of metal electrodes 105a and 105b as bus electrodes
Are formed in parallel with each other, a dielectric layer 106 is formed over the composite electrode, and a protective layer (MgO layer) 107 is further formed thereon.

On the front plate side of the glass substrate 102 serving as a back plate, address electrodes 108 are formed between the partition walls 103 so as to be orthogonal to the composite electrodes and formed in parallel with each other. A fluorescent screen 109 is provided so as to cover the wall surface and the cell bottom. Further, as shown in FIG. 5, after forming a base layer 110 (may be omitted) made of a dielectric on a glass substrate 102 serving as a back plate, an address electrode 108 is provided, and a dielectric layer 111 is further laminated thereon. After that, a structure in which a partition wall 103 and a fluorescent screen 109 are provided. A rare gas containing mainly neon and containing xenon is sealed between the front plate and the back plate. This AC type PDP
Generates an electric charge in a discharge space by performing an address discharge based on display data by one of an address electrode and a sustain electrode to generate an electric field in the discharge space by applying an AC voltage to the composite electrode on the front panel. In this way, a discharge is maintained (memory discharge). In this case, since the alternating current is applied, the direction of the electric field changes according to the cycle.

[0004]

SUMMARY OF THE INVENTION Such an AC type PD
In the manufacturing process of P, the front plate and the rear plate separately manufactured are bonded together and hermetically sealed (sealing process). That is, a sealing agent is applied to both or both of the front plate and the back plate. Next, the front plate and the rear plate are aligned and physically temporarily fixed. Then, it is placed in a firing furnace and heated to melt the low-melting glass of the sealant and bond the front plate and the back plate. At this time, cracks and distortions may occur in the protective layer (MgO layer) formed on the surface of the dielectric layer due to thermal expansion of the dielectric layer of the front plate. Further, coloring may occur due to the use of an Ag bus electrode.

Therefore, an object of the present invention is to prevent the protective layer (MgO layer) from being cracked or distorted in a sealing step in which the front plate and the rear plate are bonded and hermetically sealed, and an Ag bus electrode is provided. An object of the present invention is to provide a plasma display panel which does not cause coloring due to use.

[0006]

The above objects are achieved by the present invention described below. That is, the present invention provides an AC surface discharge type plasma display panel having a dielectric layer covering a discharge sustain electrode formed on a front panel with respect to a discharge space, wherein the DTA transition temperature of the dielectric layer is A plasma display panel having a temperature equal to or higher than a sealing temperature when the front plate and the rear plate are sealed with a sealing material.
According to the present invention, the dielectric layer covering the discharge sustaining electrodes formed on the front plate with respect to the discharge space has a DTA of not less than the sealing temperature when the front plate and the back plate are sealed with the sealing material.
It has a transition temperature (see FIG. 2). DTA stands for "differenti
al thermal analysis ", which stands for" differential thermal analysis ". Above this DTA transition temperature, the change in physical properties (thermodynamic properties) such as the coefficient of thermal expansion of the dielectric layer is remarkable, and below the DTA transition temperature, the change is slight. That is, when the DTA transition temperature of the dielectric layer is equal to or higher than the sealing temperature, it is possible to prevent cracks and distortion caused by differences in thermal expansion coefficient and the like. Therefore, in the sealing step in which the front plate and the back plate are bonded together and hermetically sealed, no crack or distortion occurs in the protective layer (MgO layer), and no coloring due to the use of the Ag bus electrode occurs. Is provided.

[0007]

Next, the present invention will be described with reference to embodiments. FIG. 1 is a diagram showing a configuration of a front plate in an AC type PDP of the present invention. 1A is a perspective view, and FIG. 1B is a cross-sectional view. In FIG. 1, 1 is a substrate, 2
Is a dielectric layer, 3 is a protective layer made of MgO (magnesium oxide), 4 is a transparent electrode made of a thin film of SnO ₂ (tin oxide), ITO (alloy of indium and tin), 5
Is a metal electrode (bus electrode). Although not shown, the seal layer is formed near the outer peripheral portion of the front plate.

A front plate of an AC type PDP is usually manufactured by providing a transparent electrode 4, a metal electrode 5, a dielectric layer 2, a seal layer, and a protective layer in this order on a substrate 1. The substrate 1 is a substrate made of soda lime glass or the like and having a thickness of about 3 mm. The transparent electrode 4 is made of a thin film such as ITO (an alloy oxide of indium and tin) and SnO ₂ (suzu oxide). IT
The manufacturing method differs between the O film and the SnO ₂ film. The ITO film is first applied to the entire surface of the glass substrate 1 by sputtering. After that, an electrode pattern is formed by photolithography. That is, a pattern of a photoresist is formed as a protective film, and the ITO film in a portion without the protective film is removed by etching using plasma or a corrosive solution. Further, the transparent electrode 4 of the ITO film is obtained by removing the protective film.

On the other hand, the SnO ₂ film is formed by a lift-off method because etching is difficult. That is, first, a photoresist pattern is formed on the glass substrate 1. The pattern in this case is a pattern in which the photoresist at the portion where the electrode is to be formed is removed. Next, the glass substrate 1
An SnO ₂ film is formed on the entire surface by CVD (chemical vapor deposition). Finally, the transparent electrode 4 of the SnO ₂ film is obtained by removing the photoresist.

A metal electrode 5 (bus electrode 5) is formed on the transparent electrode 4. The metal electrode 5 has a role of reducing the electric resistance of the transparent electrode 4 and allowing a large current to flow.
The method of manufacturing the metal electrode 5 is not limited to one. For example, three layers of Cr—Cu—Cr (chromium / copper / chromium) are formed on the substrate 1 on which the transparent electrode 4 is obtained by vapor deposition or sputtering. Then, a pattern of the metal electrode 5 is formed by photolithography.
Also, as another method, silver fine particles, resin, photosensitive resin,
A photosensitive silver tape containing glass, metal oxide, or the like as a component is stuck on the substrate 1, dried, and the electrode pattern is exposed through a photomask. After washing with a sodium carbonate solution, only the electrode pattern remains. This is fired to obtain the metal electrode 5. In this method, a metal electrode 5 mainly composed of silver is formed. According to the present invention, in the AC type PDP provided with the metal electrode 5 mainly composed of silver, the surface of the transparent panel is not colored.

A transparent dielectric layer 2 is formed so as to cover the transparent electrode 4 and the metal electrode 5. The dielectric layer 2 is formed by applying or printing paste-like low-melting glass and heating and melting the paste in a firing furnace. As will be described in detail later, the present invention is characterized by the thermodynamic properties of the dielectric layer 2. Further, a seal layer (not shown) serving as an adhesive is formed on the dielectric layer 2 by a screen printing method or a non-contact dispenser method. The seal layer is formed around the back plate. As the material of the seal layer, a material mainly composed of low-melting glass is used.

Finally, a protective layer 3 is formed. The protective layer is an insulating film that covers and protects the sustain electrode. Protective layer 3
Is the EB (electron beam) of MgO (magnesium oxide)
It is formed by vapor deposition. Further, another method for forming the protective layer 3 is obtained by applying a sol solution containing fine particles of magnesium hydroxide to the front plate, drying the sol solution, and then firing the coated sol solution.

The front plate obtained as described above and the rear plate obtained in a separate step are bonded and sealed in a subsequent sealing step. That is, by performing positioning and heating in a firing furnace, the above-described material of the seal layer is melted and welded and fixed. At this time, in the present invention, the DTA transition temperature of the dielectric layer 2 is set to be equal to or higher than the sealing temperature when the front plate and the rear plate are sealed with the material of the seal layer. The material of is specified.

FIG. 2 shows a differential thermal analyzer (differential scanning calorimeter).
FIG. 6 is a diagram of a measurement chart of the dielectric layer 2 according to FIG. The measurement chart shown in FIG. 2 is obtained by measuring low melting point glass alone in the material of the dielectric layer 2 using alumina (aluminum oxide) as a control substance. When measuring the DTA transition temperature of the dielectric layer 2, the measurement is performed on the low melting point glass alone material among the materials of the dielectric layer 2.

In the example of the material of the dielectric layer 2 shown in FIG.
The TA transition temperature is about 430 ° C. In the temperature range lower than the DTA transition temperature, as shown in FIG. 2, the change in absorbed heat energy is not large. On the other hand, in a temperature range higher than the DTA transition temperature, a change in absorbed heat energy is large. In FIG.
Above about 530 ° C., the absorbed heat energy changes abruptly because the low melting point glass softens.

FIG. 3 is a table showing characteristics of various low melting point glasses used for the dielectric layer 2. The low melting point glass shown in FIG. 3 is manufactured and provided by Asahi Glass Co., Ltd. As shown in FIG. 3, there are various low melting point glasses having a DTA transition temperature (DTA transition point) of 375 ° C. to 417 ° C. In the present invention, a low-melting glass having a DTA transition temperature equal to or higher than the sealing temperature at the time of sealing with the material of the seal layer is selected from among these various low-melting glasses. Although the dielectric layer 2 is shown as a single layer in FIG. 1, it may have two or more layers to obtain an optically flat surface. In this case, at least the DTA transition temperature of the low-melting glass used for the upper layer is set to be equal to or higher than the sealing temperature at the time of sealing with the material of the sealing layer. Usually, as the low-melting glass for the upper layer, a glass having a lower DTA softening temperature (DTA softening point) and a lower DTA transition temperature than the lower layer is used.

[0017]

[Example] DTA transition temperature of 417 ° C (part number YPT in FIG. 3)
090), a front plate and a back plate provided with a dielectric layer were sealed at a sealing temperature of 410 ° C. The protective layer of the AC type PDP thus obtained (M
No cracks or strains were observed in the (gO layer), and the Ag bus electrode was used, but there was no coloring due to it.

[0018]

[Comparative Example] DTA transition temperature of 375 ° C (part number YPT in FIG. 3)
A front plate and a back plate having exactly the same configuration as in the example except that a dielectric layer was provided using a material made of low-melting glass of (100) were sealed at a sealing temperature of 410 ° C. The protective layer (MgO layer) of the AC-type PDP thus obtained showed occurrence of cracks and distortion, and coloring due to the use of an Ag bus electrode.

[0019]

As described above, according to the present invention, in the sealing step of bonding the front plate and the back plate together and sealingly sealing them,
It is possible to provide a plasma display panel in which cracks and distortions do not occur in the protective layer (MgO layer) and do not cause coloring due to use of an Ag bus electrode.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a front plate in an AC type PDP of the present invention.

FIG. 2 is a diagram of a measurement chart by a differential thermal analyzer (differential scanning calorimeter) showing a DTA transition temperature of a dielectric layer.

FIG. 3 is a table showing characteristics of various low melting point glasses used for a dielectric layer.

FIG. 4 is an explanatory diagram of an AC type plasma display panel.

FIG. 5 is an explanatory diagram of another example of the AC type plasma display panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Dielectric layer 3 Protective layer 4 Transparent electrode 5 Metal electrode 101 Front plate 102 Back plate 103 Cell barrier 104a, 104b Sustain electrode 105a, 105b Bus electrode 106, 111 Dielectric layer 107 MgO layer 108 Address electrode 109 Fluorescent surface 110 Underlayer

Claims (1)

[Claims] 1. An AC surface discharge type plasma display panel having a dielectric layer covering a discharge sustaining electrode formed on a front panel with respect to a discharge space, wherein a DTA transition temperature of the dielectric layer is lower than that of the previous one. A plasma display panel having a temperature equal to or higher than a sealing temperature at which a face plate and a back plate are sealed with a sealing material.