JP2624346B2 - Cathode structure of gas discharge type color display panel - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cathode electrode structure of a gas discharge type color display panel.

(Prior Art) Conventionally, gas discharge type color display panels of various structures have been proposed and being put to practical use. As is well known, color display panels are classified into direct current (DC) type and alternating current (AC) type. The direct current type is improved because of its simple structure and easy gradation display. Is being promoted.

FIG. 2 shows a conventional DC type display panel (DC type PD).
FIG. 3 is a schematic diagram for explaining the basic structure of P), in which attention is focused on one pixel (dot), and only main components are shown in an enlarged sectional view along the extending direction of the cathode.

This direct-current display panel has a structure in which a back plate 10 and a front plate 12 each formed of a transparent material such as a glass substrate are opposed to each other with a discharge space 14 interposed therebetween. The back plate 10 is provided with a display anode 16 and a phosphor layer 18 as main components in an appropriate shape, size and arrangement. The front plate 12 is provided with a cathode 20, a filter and the like (not shown) as main components in an appropriate shape, size and arrangement. For example, the display anode 16 and the cathode 20 are each provided in a stripe shape so as to extend in a direction orthogonal to each other, but the present invention is not limited thereto. And, between the back plate 10 and the front plate 12,
A wall 22 is provided to serve as a spacer and to prevent false lighting and / or substantially define the discharge space 14 of one pixel. Illustration and description of other components are omitted.

In the DC color display panel having such a structure, electrodes such as the display anode 16 and the cathode 20 for generating a discharge are exposed to the discharge space 14. For this reason, the operating characteristics of the display panel are greatly affected by the material forming the electrodes and the surface condition of the electrodes. In particular, the cathode 20
During operation of the display panel, the display panel is sputtered by ions derived from the discharge gas sealed in the discharge space 14. For this reason, sputtered particles accumulate in the window region of the pixel, and the display quality of the display panel becomes fixed. Therefore, the material for forming the cathode 20 is required to be a material having excellent sputter resistance. .

(Problems to be Solved by the Invention) However, there are lanthanum hexaboride (LaB ₆ ) and the like as a conventional cathode material having excellent spatter resistance, but the cathode formed of these materials is opaque, so that the cathode portion is opaque. Reduces the aperture ratio of the window area of the pixel, and therefore, the display quality on the display panel deteriorates.

In addition, indium tin oxide (ITO: Indi
There are also transparent materials such as um Tin Oxide) or tin oxide (SnO). However, since these materials have poor sputter resistance, when they are used, the cathode is sputtered during driving of the display panel, so that the number of cathodes decreases in a short time,
The display panel has a shorter life.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cathode structure which does not cause a deterioration in quality display and has a long life, in view of the above-mentioned conventional problems.

According to the present invention, a cathode is provided on the front plate, a display anode and a phosphor layer are provided on the back plate, and the front plate and the back plate are provided. In a cathode structure of a gas discharge type color display panel formed by arranging face plates to face each other across a discharge space, a cathode has a laminated structure of an indium tin oxide film and a transparent conductive film having sputter resistance. This indium tin oxide film is used as a base provided on the front plate,
The conductive film is used as a surface film on the discharge space side.

In carrying out the present invention, preferably, the conductive film as the surface film is a zinc oxide (ZnO) film, or a film obtained by doping zinc oxide with aluminum oxide (Al ₂ O ₃ ). .

(Operation) According to the structure of the present invention, the cathode has a two-layer structure of a transparent indium tin oxide film and a transparent conductive film having sputter resistance. The indium tin oxide film is provided as a base on the side of the front plate opposite to the back plate, and the transparent conductive film having excellent sputter resistance is formed on the base as a surface film facing the discharge space. It is provided.

Therefore, since this cathode does not block light,
The aperture ratio of the window area of the pixel is not reduced.

Further, the surface on the side facing the discharge space is covered with a material having excellent sputter resistance, so that it is difficult for the display panel to be sputtered during driving. Accordingly, the conventional film reduction of the cathode does not occur as in the prior art, and even if sputtered particles adhere to the window area, the transparency of the light is not reduced because the particles are transparent. Both long life can be achieved.

Zinc oxide (ZnO) as a conductive film as this surface film
When a film is used, it is particularly excellent in spatter resistance. Although the sheet resistance of this film is somewhat high, the sheet resistance of the underlying ITO film is low, so that the wiring resistance of the entire cathode has no effect on the operation characteristics of the display panel. A material obtained by doping a ZnO film with aluminum oxide (Al ₂ O ₃ ) lowers the sheet resistance of the conductive film and further lowers the wiring resistance of the cathode.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a view for explaining an example of a cathode structure of a gas discharge type color display panel according to the present invention. FIG. 1 is an enlarged sectional view taken along an extending direction of a cathode, focusing on one pixel portion. It is. It should be noted that the figures only schematically show the shapes, sizes and arrangements of the main components so that the present invention can be understood. Except for the cathode, the same components as those shown in FIG. 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the present invention, the cathode 30 has a two-layer structure of a transparent indium tin oxide (ITO) film 32 and a transparent conductive film 34 having sputter resistance. The indium tin oxide film 32 is provided as a base on the back plate side of the front plate 12.
A transparent conductive film 34 having sputter resistance is preferably provided as a surface film on the underlayer 32 so as to cover it. Therefore, this surface film 34 is
It has a structure facing the discharge space 14 between the rear plate 10 and the rear plate 10. In this case, the thickness of the ITO film 32 can be set to an arbitrary thickness according to the design, but if it is set to an appropriate value in the range of about 0.2 to 1.0 μm, there is no problem in structure and operation characteristics.
In this case, the sheet resistance of the ITO film 32 is 2 to 10Ω / □.
It is low enough.

The thickness of the conductive film 34 can be set to any suitable thickness according to the design, similarly to the ITO film.
There is no problem in terms of structure and operation characteristics if an appropriate value is set within a range of about 1.5 μm. This conductive film 34 is preferably a zinc oxide (ZnO) film. Although the ZnO film 34 has a high sheet resistance of about 0.7 to 1 KΩ / □ at this film thickness,
Since the sheet resistance of the underlying ITO film 34 is small, the wiring resistance of the cathode 30 can be kept sufficiently low.

Instead of using the ZnO film 34, a film in which zinc oxide (ZnO) is doped with aluminum oxide (Al ₂ O ₃ ) can be used. Aluminum oxide (Al ₂ O ₃ ) is obtained by doping the ZnO film 32 for the purpose of reducing sheet resistance. If this film is used for the cathode, the wiring resistance of the cathode 30 can be reduced.

Next, an example of the main process steps of the manufacturing process of the gas discharge type color display panel having the cathode structure of the present invention will be briefly described.

First, the display anode 16 is formed in a required shape on the glass back plate 10. The anode only needs to have conductivity, and may be a thick film or a thin film. Here, for example, a thick film of nickel (Ni) is used. This is a print paste
For example, Electro-Science Laboratories (Elec
tro-Science Laboratories, Inc., product number # 2554, which was thick-film printed in the form of a display anode, dried at 150 ° C. for 1 hour, and then baked at 580 ° C. (peak value retention time 10 minutes) ). Next, a phosphor film 18 is formed on a portion corresponding to the pixel region of the back plate. Green,
As the red and blue phosphor pastes, for example, phosphor powders manufactured by Kasei Optonics (product number # P1G1: green, # KX504)
A: red and # KX501A: blue) were used, respectively. Vehicle (Electro-Science)
The mixture is made into a paste by mixing and mixing the respective phosphor pastes in an arbitrary color arrangement and dried at a drying temperature of 150 ° C. for 1 hour. Firing was performed at 530 ° C. (peak retention time: 10 minutes). On the other hand, an ITO film 32 is formed in a desired pattern on a transparent front plate 12 such as a glass substrate by sputtering or vapor deposition. Next, on the upper side of the ITO film as a lower value, a ZnO film 34, which is a transparent conductive film having excellent sputter resistance, is formed by sputtering or vapor deposition in the same pattern as the pattern of the ITO film 32. . In this case, the ITO film is not exposed to the discharge space, that is,
The conductive film 34 may be formed so as to completely cover the film 34. The ITO film 32 and the ZnO film 34 constitute the cathode 309.

Next, the wall 22 serves as a spacer for maintaining a gap between the anode 32 and the cathode, and in some cases prevents false lighting and / or partially defines a pixel.
Is formed on the back plate 10 by thick film printing. As a material of the wall 22, a glass paste (product number # 9741 manufactured by Dupont) is used, printed in a predetermined pattern in a predetermined pattern, dried at 150 ° C. for 1 hour, and then dried at 530 ° C. ° C
At a firing temperature of 10 minutes (peak retention time 10 minutes). The height of the wall 22 is arbitrarily determined.
200um.

Next, the anode 16, the phosphor film 18 and the wall 22 are thus
And the front plate 12 on which the cathode 30 is formed is sealed in combination so that the anode 16 and the cathode 30 face each other at right angles, and a He-Xe mixed gas To complete the panel.

(Effects of the Invention) As is clear from the above description, according to the cathode structure of the gas discharge type color display panel of the present invention, the cathode provided on the front plate is transparent, has good conductivity, and has a surface resistant. Since the color display panel is covered with a material having excellent sputtering characteristics, it is possible to prevent a decrease in the aperture ratio of the color display panel, and to achieve both maintenance of display quality and extension of life.

Even with the cathode structure of the present invention, the wiring resistance can be kept low, so that the size of the display panel can be increased.

[Brief description of the drawings]

FIG. 1 is a view for explaining an example of a cathode structure of a gas discharge type color display panel of the present invention, and FIG. 2 is a view for explaining a basic structure of a conventional DC type display panel (DC type PDP). FIG. 10 ... Back plate, 12 ... Front plate 14 ... Discharge space, 16 ... Display anode 18 ... Phosphor film, 22 ... Wall 30 ... Cathode 32 ... Indium tin oxide (ITO) film 34 ... Transparent conductive film with sputter resistance

Continuation of the front page (72) Inventor Masao Ikehata 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (56) References JP-A-62-154435 (JP, A) JP-A-1- 194240 (JP, A)

Claims (2)

(57) [Claims] 1. A gas discharge comprising a cathode provided on a front plate side, a display anode and a phosphor layer provided on a back plate side, and a front plate and a back plate which are arranged to face each other with a discharge space therebetween. In the cathode structure of a color display panel, the cathode has a laminated structure of an indium tin oxide film and a transparent conductive film having sputter resistance, and the indium tin oxide film is used as a base provided on a front plate, The cathode structure of a gas discharge type color display panel, wherein the conductive film is used as a surface film on the discharge space side. 2. The gas discharge type color display panel according to claim 1, wherein said conductive film is made of zinc oxide (Zn oxide).
O) A cathode structure of a gas discharge type color display panel, wherein the film is a film or a film in which the zinc oxide is doped with aluminum oxide (Al ₂ O ₃ ).