JPH0765729A - Plasma display panel and manufacture thereof - Google Patents

Abstract

(57) [Summary] [Object] With respect to an AC PDP and its manufacturing method, it is an object to suppress the generation of bubbles in a dielectric layer which causes a decrease in breakdown voltage, and to improve reliability. A discharge portion of the display electrodes X and Y is covered with a dielectric layer 17 made of non-foaming low melting point glass,
The portion of Y outside the sealing region ES is manufactured by coating with a low melting point glass layer 50 capable of chemical etching.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC type plasma display panel (PDP) and its manufacturing method.

[0002] PDPs are self-luminous display devices that are advantageous in terms of display brightness, and because they are capable of large screens and high-speed display, they have attracted attention as display devices that replace CRTs.

[0003]

2. Description of the Related Art Here, the configuration of a conventional PDP will be described with reference to FIGS. 1 and 2 showing an embodiment of the present invention.

In the PDP, the glass substrate 11 on the display surface H side and the glass substrate 21 on the back side are arranged so as to face each other, and the peripheral portions of the facing regions of the pair of glass substrates 11 and 21 are sealed, whereby the inside of the PDP is internally sealed. The display device has a discharge space 30 formed of a gap of about 70 to 150 μm.

In the matrix display type PDP, a large number of electrodes are arranged in a grid pattern, and a unit light emitting region defined at the intersection of each electrode is selectively made to emit light, thereby displaying arbitrary figures and characters. Be seen. A region within the display surface H where the unit light emitting region is defined becomes a display region EH.

The electrodes X, Y and A provided on the glass substrates 11 and 21 (the electrode A on the glass substrate 21 is shown in FIG. 2) are connected to the glass substrates 11 and 21 from the discharge space 30.
Is led out to the end portion thereof and connected to an external drive circuit by a flexible printed wiring board (not shown) or the like. In order to facilitate the electrical connection with the drive circuit, the glass substrates 11 and 21 are so arranged that the size and the position of the facing arrangement are such that both end edges of each of the glass substrates 11 and 21 extend beyond the end edges of the other glass substrate. It has been selected.

Now, an AC type P that alternately applies a predetermined voltage to a pair of electrodes X and Y that define a main discharge cell.
In the DP, as shown in FIG. 1, the electrodes X and Y are covered with a dielectric layer 17 made of low melting point glass.

In AC driving in which discharge is maintained by wall charges, the discharge portions of the electrodes X and Y, that is, the display area EH.
The dielectric layer 17 may be provided only on the portion corresponding to. However, in actuality, in order to prevent the electrodes X and Y from being oxidized by various heat treatments performed after the electrodes are formed in manufacturing the PDP, the sealing glass 31 is formed from the stage before the firing of the dielectric layer 17.
It is necessary to avoid exposing the electrodes X and Y until the stage of completing the sealing by.

Therefore, conventionally, in manufacturing the glass substrate 11, the low-melting-point glass is applied to almost the entire surface of the glass substrate 11 on which the electrodes X and Y are provided, and the glass substrate 11 is baked. The dielectric layer 17 is provided so as to cover the entire X and Y, and an etching process is performed to remove a part of the dielectric layer 17 to expose the ends (external connection parts) of the electrodes X and Y after sealing. It was being appreciated. That is, a single low melting point glass layer (dielectric layer 1
By 7), the entire electrodes X and Y including the external connection portion were protected. As the material of the dielectric layer 17, a low-melting-point glass paste of a defoaming type and having a composition easy to etch was used.

[0010]

The defoaming type low melting point glass paste is suitable for firing at a high temperature (a temperature sufficiently higher than the softening point) at which the gas generated in the layer being fired can be released to the outside. A good paste, according to which
It is possible to obtain the dielectric layer 17 having excellent transparency as compared with the non-defoaming type that is fired at a temperature near the softening point.

However, when the defoaming type paste is used, the gas adheres to the surfaces of the electrodes X and Y made of metal at the time of firing, and is relatively large above the electrodes X and Y in the dielectric layer. There is a problem that bubbles are easily generated.

When such bubbles are generated, the breakdown voltage is lowered particularly between the electrodes X and Y which are responsible for surface discharge and the address electrode A for selective light emission of the unit light emitting region in the surface discharge PDP. Unnecessary discharge may occur, which may disturb display and damage the address electrode A and the drive circuit.

In view of the above problems, it is an object of the present invention to suppress the generation of bubbles in the dielectric layer, which causes a decrease in breakdown voltage, and improve reliability.

[0014]

[Means for Solving the Problems] P according to the invention of claim 1
In order to solve the above problems, the DP is an AC type plasma display panel 1 in which the discharge portions of the display electrodes X and Y are covered with a dielectric layer 17, as shown in FIG.
The dielectric layer 17 is made of non-defoaming low melting point glass.

According to a second aspect of the present invention, there is provided a method of forming the display electrodes X and Y on the substrate 11, and the substrate 11
Of the electrode formation surface of the display area EH and the sealing area E
The dielectric layer 17 made of non-defoaming low-melting glass is provided on a portion other than the outside of S, and the low-melting glass layer 50 capable of chemical etching is provided on the other portion.
And the low melting glass layer 50 allows the display electrodes X,
The step of covering the entire Y and the substrate 2 different from the substrate 11.
1 and 2 are opposed to each other and the periphery of these substrates 11 and 21 is sealed with a sealing glass 31, and a portion of the low melting point glass layer 50 outside the sealing glass 31 is removed by chemical etching. And a step of exposing the end portions of the display electrodes X and Y.

In the method according to the third aspect of the present invention, the dielectric layer 17 and the low melting point glass layer 50 are arranged such that a layer having a lower softening point of these two layers is located above a layer having a higher softening point. It is provided so as to partially overlap.

[0017]

The non-defoaming low-melting-point glass is completely fired at a stage where the firing temperature is near the softening point and the gas generated during firing is in a sufficiently small bubble state before the gas is expanded. Therefore, the dielectric layer 17 covering the discharge portions of the display electrodes X and Y is substantially homogeneous, and a higher breakdown voltage can be obtained as compared with the case where the film quality is nonuniform with large bubbles.

When manufacturing the PDP 1, display electrodes X and Y are used.
The low melting point glass layer 50, which is covered with the dielectric layer 17 at the discharge portion and chemically etchable at the end portion, is formed after the formation thereof and before the sealing is completed.
It is covered with and protected.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view showing the structure of the main part of a PDP 1 according to the present invention, and FIG. 2 is a perspective view showing the external shape of the PDP 1.
FIG. 3 is an exploded perspective view showing a basic structure of a portion of the PDP 1 corresponding to one pixel EG.

In these figures, the PDP 1 has a three-electrode structure in which a pair of display electrodes X and Y and an address electrode A correspond to a unit light emitting region EU of matrix display, and is classified according to the arrangement form of the phosphors. It is a surface discharge type PDP called as a reflection type.

The display electrodes X and Y for surface discharge are provided on the glass substrate 11 on the display surface H side, and the inner portion of the sealing area ES including the discharge portion corresponding to the display area EH is A.
The discharge space 30 is covered with a C drive dielectric layer 17. The thickness of the dielectric layer 17 is about several tens of μm. On the surface of the dielectric layer 17, a MgO film 18 having a thickness of about several thousand Å is provided as a protective film.

Since the display electrodes X and Y are arranged on the display surface H side with respect to the discharge space 30, a wide band-shaped transparent conductive film 41 for widening the surface discharge and its conductivity. The bus metal film 42 having a narrow width is stacked on the outer end side in order to supplement the property. The transparent conductive film 41 is composed of a Nesa film (tin oxide film) having a thickness of several thousand Å to 1 μm, and the bus metal film 42 is composed of, for example, a thin film having a three-layer structure of chromium-copper-chrome.

On the other hand, the address electrode A for selectively emitting light in the unit light emitting region EU is provided with the glass substrate 21 on the back side.
The display electrodes X and Y are arranged on the display electrode at a pitch of, for example, about 200 μm
It is arranged so that it is orthogonal to. The address electrode A is a thick film electrode obtained by firing a conductive paste, and even if it is exposed, it is hardly altered by various heat treatments.

A discharge space 30 is provided between each address electrode A.
Striped barrier ribs 29 having a width of about 50 μm that define the gap size of the discharge space 3 are provided.
0 is divided for each unit light emitting area EU in the line direction (extension direction of the display electrodes X and Y). In addition, the glass substrate 21
Covers the upper surface of the address electrode A and the inner surface of the rear surface including the side surface of the partition 29 so that R (red), G
Phosphors 28 of three primary colors of (green) and B (blue) are provided. The alphabets R, G, and B in FIG. 3 indicate the emission colors of the phosphors 28. The phosphor 28 is excited by the ultraviolet rays emitted by the discharge gas in the discharge space 30 during surface discharge to emit light.

Each pixel (dot) EG constituting the display screen
Are associated with three unit light emitting regions EU having the same area and arranged in the line direction. In each unit light emitting region EU, a surface discharge cell (main discharge cell for display) is defined by the display electrodes X and Y, and the display electrode Y and the address electrode A are defined.
And define address discharge cells for selecting display or non-display. As a result, among the phosphors 28 that are continuous in the extension direction of the address electrode A, each unit light emitting area EU
The portion corresponding to can be selectively made to emit light, and R,
Full-color display is possible by combining G and B.

Now, in the PDP 1, the dielectric layer 17
Is a non-defoaming low-melting-point glass containing PbO as a main component and SiO ₂ , Al ₂ O ₃ , B ₂ O _{3 and the} like. In the case of non-defoaming low-melting-point glass, the firing temperature is set near the softening point (about 500 to 600 ° C.), and firing is performed at a stage where the gas generated during firing is in a sufficiently small bubble state before expansion. Complete. Therefore, the dielectric layer 17
Is a uniform layer without large bubbles, and a predetermined breakdown voltage is secured between the display electrodes X and Y and the address electrode A.

However, the low melting point glass containing SiO ₂ has excellent chemical resistance and is difficult to etch. So PD
In P1, before the completion of sealing, as shown by the dashed line in FIG. 1, the external connection parts of the display electrodes X and Y are covered with a low-melting-point glass layer 50 which can be easily etched. The layer 50 and the dielectric layer 17 prevent the display electrodes X and Y from being oxidized.

Next, a method of manufacturing the PDP 1 having the above structure will be described with reference to FIG. The PDP 1 is provided with predetermined constituent elements separately for each glass substrate 11 and 21,
After that, the glass substrates 11 and 21 are overlapped and sealed, and a series of steps of exhausting the inside and filling the discharge gas is manufactured.

In manufacturing the glass substrate 11 side, first, the glass substrate 11 is formed by film formation by vapor deposition or sputtering, and patterning by photolithography.
A transparent conductive film 41 and a bus metal film 42 are sequentially formed on the display electrodes X and Y.

Next, among the electrode forming surfaces of the glass substrate 11,
The non-defoaming first low-melting-point glass paste is applied to a portion including the entire display area EH and excluding the outside of the sealing area ES, and a second low-melting composition having a composition capable of chemical etching is applied to other portions. A melting point glass paste is applied, and the display electrodes X and Y are entirely covered with the first and second low melting point glass pastes. At this time, in order to complete the coating,
The two paste layers are applied so as to overlap each other with a width of, for example, about 1 mm. Then, in the overlapping portion (overlap portion), the low-melting-point glass paste having a high softening point is placed first so that the layer having a lower softening point of the two paste layers is located above the layer having a higher softening point. Apply. In the example of FIG. 1, the first low melting point glass paste corresponding to the dielectric layer 17 is first applied and the second low melting point glass layer 50 corresponding to the second low melting point glass layer 50 is applied.
The low melting point glass paste of is applied later.

Subsequently, the first and second low melting glass pastes are fired at a temperature near the softening point of the first low melting glass paste to protect the dielectric layer 17 and the electrode end portions. And 50. In the temperature decreasing step after firing, since the stacking order of the overlapping portions of the two layers is determined according to the height of the softening point as described above, the lower layer is always cured first. As a result, the gas generated in the lower layer during firing diffuses to the outside through the upper layer, and the upper layer does not confine the gas. When the stacking order is reversed and the gas is confined in the lower layer, the gas itself oxidizes or the gas bubbles explode and oxidizes by the outside air through the pinholes. The electrodes X and Y may be broken.

In this way, the dielectric layer 17 and the low melting point glass layer 50 are provided, and the display electrodes X and Y are protected,
The MgO film 18 is provided by electron beam evaporation or the like. Then, one glass substrate is coated with a glass paste for sealing in a ring shape having a width of about 5 mm, and the glass substrates 11 and 21 are formed.
Are opposed to each other and heat treatment is performed. By this heat treatment, the glass paste is fired to become the sealing glass 31, and the discharge space 30 is sealed.

After the sealing, the low melting point glass layer 50 covering the end portions of the display electrodes X and Y, that is, the sealing inside the low melting point glass layer 50 in order to enable electrical connection to the outside. The portion outside the glass 31 is removed. The low melting point glass layer 50 is removed by wet etching (chemical etching) in which the integrated glass substrates 11 and 21 are immersed in a nitric acid solution.

According to the above-mentioned embodiment, since the display electrodes X and Y are protected by the two kinds of low melting glass,
The material of the dielectric layer 17 can be optimized without considering the possibility of etching.

According to the above-described embodiment, since the dielectric layer 17 and the low melting point glass layer 50 are provided so as to overlap each other, it is possible to avoid the exposure of the display electrodes X and Y at the boundary between the two layers. . Further, since the stacking order of the two layers is specified by the softening point, it is possible to prevent disconnection of the display electrodes X and Y due to gas entrapment in the lower layer.

In the above-described embodiment, the example in which the boundary position between the dielectric layer 17 and the low melting point glass 50 is set within the sealing area ES where the sealing glass 31 is provided is described, but the boundary position is in the display area EH. It should be outside.

[0037]

According to the present invention, it is possible to suppress the generation of bubbles in the dielectric layer, which causes a decrease in breakdown voltage, prevent damage to the electrode due to unnecessary discharge, and improve reliability.

According to the second aspect of the present invention, the material of the dielectric layer can be optimized without considering the possibility of etching. According to the invention of claim 3, the display electrode can be protected more reliably.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a main part of a PDP according to the present invention.

FIG. 2 is a perspective view showing an external shape of a PDP.

FIG. 3 is an exploded perspective view showing a basic structure of a portion corresponding to one pixel of a PDP.

[Explanation of Codes] 1 PDP (Plasma Display Panel) 11, 21 Glass Substrate (Substrate) 17 Dielectric Layer 31 Sealing Glass 50 Low Melting Glass Layer EH Display Area ES Sealing Area X, Y Display Electrodes

Claims (3)

[Claims] 1. An AC type plasma display panel (1) in which a discharge part of a display electrode (X) (Y) is covered with a dielectric layer (17), wherein the dielectric layer (17) is non-conductive. A plasma display panel comprising a low-melting glass having a defoaming property. 2. A method of manufacturing a plasma display panel (1) according to claim 1, comprising the steps of forming the display electrodes (X) (Y) on a substrate (11); Display area (EH) of the electrode formation surface
The dielectric layer (17) made of non-defoaming low-melting glass is provided in a portion including the outside of the sealing region (ES), and the low-melting glass layer capable of chemical etching is provided in other portions ( 50) and covering the whole of the display electrodes (X) (Y) with the dielectric layer (17) and the low melting point glass layer (50); and a substrate (21) different from the substrate (11). ) And face each other,
Around the periphery of these substrates (11) and (21) is sealed glass (3
1) The step of encapsulating, and the portion of the low melting point glass layer (50) outside the encapsulating glass (31) is removed by chemical etching to expose the end portions of the display electrodes (X) (Y). A method of manufacturing a plasma display panel, comprising: 3. The method of manufacturing a plasma display panel according to claim 2, wherein the dielectric layer (17) and the low melting point glass layer (50).
Is partially overlapped so that the layer having a lower softening point of these two layers is on the upper side of the layer having a higher softening point, and the method is provided.