JPH10177845A - Ac type plasma display panel and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a beautiful and defect-free screen image owing to extremely stabilized gas electric discharge by using a glass thin plate on which a protective film is formed as dielectric having a protective film. SOLUTION: Address electrodes 12, ribs 13, phosphors 14 (red color 14R, blue color 14B, green color 14G) are formed respectively on a back surface glass substrate 10 of 3mm thickness. Then, on a glass thin plate 20 of 30μm thickness, a MgO protective film 21 is formed and the protective film 21 is formed on the glass this plate 20 by means of an electron beam vapor deposition method with an area for covering the total screen image area. Subsequently, on a front surface glass substrate 40 of 30mm thickness, a transparent conductive film 41 for the purpose of display and the bus electrode 42 are formed. The transparent dielectric film 41 for the purpose of display and the bus electrode 42 are assigned to a displaying electrode pair 70, subjected to AC electric discharge to force the phosphors 14 to illuminate. Meanwhile, in the case of screen image display, a plastic stripe 43 for the purpose of nicely displaying contrast is formed in the border of a display electrode part 70, namely in the border of a pixel. A screen surface becomes sharp in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an AC type plasma display panel which is an image display device utilizing gas discharge and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, large displays have become widespread as image display devices, but conventional CRT displays have become heavy with the increase in size of cathode ray tubes. On the other hand, a color plasma display has been announced and marketed as a thin and large-screen display by several electric manufacturers. (Den Shinoda, “A
C-type plasma display panel <Expectation for low cost and large size with simple structure>", Electronics Technology, Vol.
(1996) pp. 63-67) and the like. At present, two types of color plasma displays, a DC type color plasma display and an AC type color plasma display, have been put into practical use. However, the DC type color plasma display has a complicated structure of the discharge cell, and the yield of the panel at the time of production is poor, which is not linked to mass production. On the other hand, the AC-type plasma display has a simple structure of the discharge cells and can be mass-produced.

The AC type color plasma display is roughly divided into a counter discharge type panel in which display discharge is performed between electrodes of a rear glass substrate and a front glass substrate and a display electrode pair 70 of a front glass substrate 40 which performs display discharge. Do with 3
There are two types of structures: an electrode surface discharge type panel (a conceptual diagram of the panel structure is shown in FIG. 6). Applying the phosphor 14 which is indispensable for color display with a large area as much as possible in the discharge cell 51 leads to higher brightness and higher efficiency, and protects the phosphor from ion bombardment during AC display discharge and prevents deterioration. Prevention leads to a longer panel life. In the three-electrode surface-discharge type panel, the phosphor 14 is not formed on the front glass substrate 40 so as not to receive ion bombardment at the time of the AC display discharge, but the rib 13 and the rear glass substrate 10 (on the address electrode 12). The surface area of the phosphor 14 is larger than that of a counter-discharge type panel which cannot be applied on the electrode due to the deterioration of the phosphor, which is very advantageous in terms of luminous efficiency. (T. Shinodat.
al. , “Development of Techn.
logosin Large-Area Colo
rac Plasma Displays, "SID
1993 pp. 161-164 (1993). ).
Also, the phosphor 14 can be applied without color mixing by using the rib 13 as a deep bank to separately apply RGB. There is no need for a step of removing the phosphor of the electrode as in the case of the opposed type. Further, in the case of the opposed type, the phosphor residue degrades the stability of display discharge. For the above reasons, the AC three-electrode surface-discharge color plasma display currently boasts an overwhelming share among thin large-screen plasma displays.

Here, the structure and manufacturing method of the AC type three-electrode surface discharge type color plasma display will be described in more detail with reference to FIGS. 2, 3 and 6. FIG. FIG. 2 is a diagram showing a process for manufacturing a panel component of a conventional AC color plasma display, FIG. 3 is a diagram showing a process for assembling and manufacturing a conventional AC color plasma display, and FIG. It is a conceptual diagram for explaining.

In the three-electrode surface-discharge type panel, in order for a high-definition large-screen panel to clearly display an image over a long period of time, first, address discharge and display discharge must be stably generated in all cells for a long period of time. The most important point is the quality of the dielectric layer 44 formed on the front glass substrate 40 and the quality and uniformity of the MgO protective film 21 formed on the dielectric layer. Normally, first, the display electrode pair 7 is placed on the front glass substrate 40.
As 0, the transparent conductive film ITO41 is formed by a thin film technique or a thick film technique. Next, a Cr / Cu / Cr layer is formed as a bus electrode 42 for preventing a voltage drop by using a thin film technique or a thick film technique using an Ag paste. Further, a PbO-based glass layer having a low melting point is applied thereon as a transparent dielectric layer 44 by a thick film technique and fired.
An MgO protective film 21 is formed thereon by a thin film technique.

A necessary characteristic of the transparent dielectric layer 44 is that the transparent dielectric layer 44 is formed on the display surface side, so that the transmittance for visible light is 80%.
Above, the surface is smooth and there are no bubbles inside. There must be no pinholes or bubbles, and the thickness of about 30 μm must be uniform over the entire surface so that the withstand voltage is 1 KV or more. Another problem is that it does not react with other members in the heat treatment process until panel completion and does not cause cracking or deterioration. At present, when the transparent dielectric layer 44 is formed, a low-melting PbO-based glass paste is applied by screen printing and baked, but in order to eliminate bubbles and pinholes in the transparent dielectric layer 44, As shown in FIG. 2B, a method is known in which screen printing and firing at 530 ° C. are repeated three times to make the thickness of the transparent dielectric layer 44 30 μm (Kiho Kawazu, The 10th intern).
nationalmicroelectronics C
onference, Ohmiya (1996). ).

However, in the above method, firing at 530 ° C. is repeated three times in the step of forming the transparent dielectric layer 44.
0 thermal shrinkage problem, display transparent conductive film 41 and bus electrode 4
2 and the problems caused by the movement of atoms due to thermal diffusion between the members (front glass substrate 40, transparent conductive film 41 for display, bus electrode 42, transparent dielectric layer 44). In addition, it is extremely difficult to completely eliminate pinholes and bubbles over the entire screen of the transparent dielectric layer 44 and to keep the film thickness constant, which causes a problem in that a discharge phenomenon becomes uneven depending on the location when the panel is formed. There was also. Since the firing temperature characteristic of the PbO-based glass paste cannot be set to a very low temperature in accordance with the temperature (450 ° C.) at the time of glass sealing, when firing at 530 ° C., the viscosity is high and the surface of the transparent dielectric layer 44 However, there is also a problem that is not sufficiently smooth. There is also a problem that the visible light transmittance of the transparent dielectric layer 44 varies depending on the location due to unevenness in the firing temperature. Of course, the labor in the manufacturing process and the heat energy cost in firing are also serious problems.

The main role of the MgO protective film 21 is twofold.
One is to protect the transparent dielectric layer 44 from ion bombardment in order to eliminate the contamination of the inside of the panel due to the decomposition of PbO used for the low melting point glass of the transparent dielectric layer 44 due to ion bombardment occurring at the time of display discharge. Spatter resistance. The other is that the secondary electron emission efficiency for reducing the discharge starting voltage at the time of AC discharge is high, there is no deterioration after long-time lighting, and the margin between the discharge sustaining voltage and the discharge starting voltage can be appropriately set. And the stability with respect to discharge phenomena, such as the ability to properly retain wall charges. A necessary characteristic required for the MgO protective film 21 is how to form the film having the above role on the transparent dielectric layer 44 with a uniform and uniform film surface as a whole. As a method of forming the MgO protective film 21, a sol-gel method, a screen printing method, and the like have been studied, but an electron beam (EB) evaporation method has reached practical use. Also, M
The use of a thin film such as La ₂ O ₃ or CeO ₂ as a substitute for the gO protective film has been studied, but has not been put to practical use at present.

However, in the current EB evaporation method, MgO
No matter how much effort is made to form a protective film about 500 nm uniformly and uniformly over the entire screen, the transparent dielectric layer to be deposited on the entire screen is uniformly and uniformly stable. If not smooth, M formed on the surface of the transparent dielectric layer
The gO protective film itself has a problem that a pinhole or a crack is generated in the gO protective film, a part where spatter resistance is impaired is generated, and a panel is contaminated or a part where a discharge phenomenon is not stable occurs.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a high transmittance to visible light as a dielectric layer, a smooth surface, no pinholes, MgO with no bubbles inside and a uniform thickness over the entire surface so that the withstand voltage becomes 1 KV or more
It is an object of the present invention to provide a plasma display panel which does not cause a problem when forming a protective film and which eliminates a baking step so as to further reduce energy costs, in particular, an AC type plasma display panel and a method of manufacturing the same.

[0011]

Means for Solving the Problems A first invention of the present invention is:
In an AC type plasma display panel in which an address electrode, a rib, and a phosphor are provided on a rear glass substrate, and a display electrode pair is disposed opposite to the address electrode, a rib, and a phosphor having a protective film, An AC-type plasma display panel using a thin glass plate on which a protective film is formed.

According to a second aspect of the present invention, there is provided the AC type plasma display panel according to the first aspect, wherein a colored glass is used as the glass thin plate.

Further, a third invention is the AC type plasma display panel according to the first invention, wherein a plurality of glasses are used as the glass thin plate.

Further, in the AC type plasma display panel according to the first, second, or third aspect of the present invention, the dielectric glass thin plate on which the protective film is formed is formed by using an address electrode,
Rib, sandwiched between the rib on the back glass substrate on which the phosphor was formed, and the front glass substrate on which the display electrode pair was formed, sealed the whole with low melting point glass, filled with discharge gas, and formed a panel And a method of manufacturing an AC type plasma display panel.

Further, in the AC-type plasma display panel according to the first, second or third aspect of the present invention, the dielectric thin glass plate on which the protective film is formed is formed by using an address electrode,
After the ribs and the ribs on the rear glass substrate on which the phosphor is formed are in close contact with each other and sealed with a low-melting glass, and filled with a discharge gas, the glass thin plate and the front glass substrate on which the display electrode pair is formed are bonded with an adhesive. A method for manufacturing an AC type plasma display, characterized in that a panel is formed by bonding together.

As described above, according to the present invention, since a glass thin film on which a protective film is formed is used as a dielectric having a protective film, pinholes and bubbles are completely removed over the entire screen and the film thickness is kept constant. It becomes possible.

Further, a thin dielectric glass plate on which a protective film is formed is sandwiched between a rib on a rear glass substrate on which address electrodes, ribs and phosphors are formed, and a front glass substrate on which a display electrode pair is formed. Then, the whole is sealed with low-melting glass and filled with a discharge gas to form a panel, so that a heat treatment step in the step of forming a dielectric layer is not required.

Along with this, the problem of heat shrinkage of the front glass substrate, deterioration of various electrodes such as the transparent conductive film for display and bus electrode, and the problem of the front glass substrate, the transparent conductive film for display, The problem caused by the movement of atoms due to thermal diffusion between members such as an electrode and a transparent dielectric layer is eliminated. Further, the problem that the visible light transmittance of the dielectric layer changes depending on the place due to the unevenness of the firing temperature is eliminated.
The labor in the manufacturing process and the heat energy cost in firing are also unnecessary.

Further, no matter how much effort is made to form an MgO protective film uniformly and uniformly over the entire screen with a thickness of about 500 nm by the current EB vapor deposition method, the dielectric layer to be vapor-deposited is a glass substrate. The sputter resistance is spoiled without causing pinholes or cracks in the MgO protective film formed on the surface of the glass substrate, since the entire screen is uniform and uniformly stable and smooth. Since there are almost no places, the panel is not contaminated, and there are almost no places where the discharge phenomenon is unstable.

Further, the dielectric thin glass plate on which the protective film is formed is brought into close contact with the address electrode, the ribs, and the ribs on the rear glass substrate on which the fluorescent material is formed, sealed with a low melting point glass, and filled with a discharge gas. Because of the chip-off, confidentiality as a gas discharge panel is achieved at this stage.

Accordingly, in the subsequent steps, a panel can be manufactured using low-melting-point sealing glass or the like irrespective of airtightness for stabilizing the discharge gas. A sealing member comprising a component A in which an address electrode 12, a rib 13, and a phosphor 14 are respectively formed on a rear glass substrate 10, a component C in which an MgO protective film 21 is formed on a thin glass plate, and a display electrode pair The component D of the front glass substrate 40 on which the 70 is formed is bonded at normal temperature with an adhesive to form a panel. Therefore, for example, it is easy to form the transparent conductive film 71 for electromagnetic wave shielding and the antireflection film 72 on the component D of the front glass substrate 40 in advance. In addition, since the need for vacuum sealing is eliminated, the range of selection of materials for the display transparent conductive film 41 and the bus electrode 42 is expanded. Furthermore, it becomes possible to use a color filter of an organic pigment (see FIG. 8).

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments. In the AC type plasma display panel, the dielectric layer is not formed by printing and firing glass paste, but is made of a thin glass plate, and an MgO protective film of this thin plate is formed. This thin glass plate has good transmittance of visible light when formed into a panel, is smooth, has a constant thickness, and has a coefficient of expansion of the MgO protective film so as not to be damaged by a heat cycle in a later process. It is important to match

<Example 1> A dielectric thin glass plate having a protective film formed thereon was placed between a rib on a rear glass substrate on which address electrodes, ribs, and phosphors were formed, and a front glass substrate on which a display electrode pair was formed. Then, a 21-inch AC type three-electrode surface discharge type color plasma display panel was manufactured by a manufacturing method in which the whole was sealed with a low-melting glass and filled with a discharge gas to form a panel.

The schematic structure of this panel is as shown in FIG. First, according to the process shown in FIG. 1A, an address electrode 12, a rib 13, and a phosphor 14 (three-color red light-emitting phosphor 14R, blue light-emitting phosphor 14B, green light-emitting) are formed on a back glass substrate 10 having a thickness of 3 mm. Phosphor 14G)
Each was formed by the screen printing method (part A). FIG. 9 shows a part of the part A. The pitch between the address electrodes 12 and the ribs 13 is 0.22 mm, and the pitch between the phosphors 14R, 14B, and 14G is 0.66 mm.

Next, according to the process shown in FIG. 1C, an MgO protective film 21 was formed on a glass thin plate 20 having a thickness of 30 μm (referred to as part C). FIG. 10 shows a part of the part C. The MgO protective film 21 has an area covering the entire screen and is formed on the glass thin plate 20 by an electron beam evaporation method.

Next, according to the process shown in FIG. 1D, a pair of display electrodes was formed on a front glass substrate 40 having a thickness of 3 mm (part D). 41 indicates a transparent conductive film for display and a transparent conductive film ITO, 42 indicates a bus electrode,
3 shows a Cr / Cu / Cr layer. A part of this part D is shown in FIG.
Shown in Note that, in this step, a pattern formation method by etching using a vacuum evaporation method and a photolithography method was used. The display transparent conductive film 41 and the bus electrode 42 are Xn and Yn.
The pair of Xn and Yn are subjected to an AC discharge during display discharge, and the phosphor 14 emits light. The pitch of the display electrode pair 70 is 0.66 mm.
It is. In addition, a black stripe 43 for displaying an image with good contrast when displaying an image is formed by a display electrode pair 70.
, That is, at the boundary between pixels. This pitch is also 0.66 mm.

Finally, according to the process shown in FIG. 4, the components were aligned to form a panel. That is, the glass thin plate 20 on which the MgO protective film 21 is formed is
Back glass substrate 1 on which 2, rib 13 and phosphor 14 are formed
The low melting point glass 3 is sandwiched between the ribs 13 ′ on the front side and the front glass substrate 40 on which the display electrode pairs 70 are formed.
The panel is sealed with 2 and filled with the discharge gas 50 to form a panel. As can be seen from FIG. 13, since the positional accuracy between the parts A, C, and D is not required and the alignment in each sealing step is easy, the black stripe 43 is formed on the front glass substrate 40 and the rear glass substrate is formed. 10 black rib tops 1
3 'and a so-called black matrix could be formed, and the screen became sharp.

<Embodiment 2> A dielectric thin glass plate on which a protective film was formed was brought into close contact with ribs on a rear glass substrate on which address electrodes, ribs, and phosphors were formed and sealed with low-melting glass. Is satisfied, and the glass thin plate and the front glass substrate on which the display electrode pair is formed are bonded with an adhesive to form a panel, thereby forming a panel.
An inch AC three-electrode surface discharge type color plasma display panel was manufactured.

The schematic structure of this panel is as shown in FIG. First, in the same manner as in Example 1, according to the process shown in FIG. 1A, an address electrode 12, a rib 13, and a phosphor 14 (three-color # 14R,
4B, 14G) were formed by a screen printing method to obtain parts A. FIG. 9 shows a part of the part A. The pitch between the address electrodes 12 and the ribs 13 is 0.22 mm, and the pitch between the phosphors 14R, 14B, and 14G is 0.66 mm.

Next, an MgO protective film 21 was formed on a thin glass plate 20 having a thickness of 30 μm according to the process shown in FIG. FIG. 10 shows a part of the part C. The MgO protective film 21 has an area covering the entire screen and is formed on the glass thin plate 20 by an electron beam evaporation method.

Next, a display electrode pair was formed on a front glass substrate 40 having a thickness of 3 mm according to the process shown in FIG. This part D
Are shown in FIG. Note that, in this step, a pattern formation method by etching using a vacuum evaporation method and a photolithography method was used. The display transparent conductive film 41 and the bus electrode 4
Reference numeral 2 denotes a display electrode pair 70 of Xn and Yn. When a display discharge occurs, an AC discharge is applied to the pair of Xn and Yn, and the phosphor 14 emits light. The pitch of the display electrode pair 70 is 0.66 mm. In addition, a black stripe 43 for showing an image with good contrast at the time of image display was formed at the boundary between the display electrode pairs 70, that is, at the boundary between pixels. This pitch is also 0.66 mm.

Here, since the post-process is at room temperature, the transparent conductive film 71 for shielding electromagnetic waves is provided on the surface of the front glass substrate 40 on which the display transparent conductive film 41 and the bus electrode 42 are not formed.
The anti-reflection film 72 is formed in advance, and measures are taken for measures to suppress disturbance due to electromagnetic waves and measures for reflection of external light on the screen.

Finally, according to the process shown in FIG. 5, each component was aligned and formed into a panel. That is, the glass thin plate 20 on which the MgO protective film 21 is formed is
Back glass substrate 1 on which 2, rib 13 and phosphor 14 are formed
The chip was sealed with a low-melting glass 32 in close contact with the rib 13 'on the top of the chip 0, filled with a discharge gas 50, and chipped off. At this stage, airtightness as a gas discharge panel was achieved.

The sealed body of the parts A and C and the part D of the front glass substrate 40 on which the display electrode pair 70 is formed are bonded at room temperature using an adhesive to form a panel. As can be seen from FIG. 13, there is no need for positional accuracy between the parts A, C, and D, and the alignment in each sealing step is easy, so that
The black stripes 43 were formed on the front glass substrate 40 to form a so-called black matrix with the black rib tops 13 'of the rear glass substrate 10, and the screen became sharp.

The two types of color plasma display panels produced in this manner were turned on for image display by the lighting method of the conventional AC type three-electrode surface discharge type color plasma display panel, and the stability of the discharge phenomenon was evaluated.

<Evaluation Results of Example 1> When the panel thus manufactured was turned on, the image flicker disappeared over the entire 21-inch screen. On average, about 10 erroneous discharge displays were found on the commercially available panel, but this number was reduced to three on this panel.

<Evaluation Results of Example 2> When the panel thus manufactured was lit, the screen flicker disappeared over the entire 21-inch screen. On average, about 10 erroneous discharge displays were found on the commercially available panel, but this number was reduced to five on this panel. In addition, reflection of external light on the screen was reduced by the antireflection film.

[0038]

As described above, according to the present invention, the MgO protective film, which is the largest point on the front substrate side of the AC type color plasma display panel, can be formed uniformly over a large screen. When displaying an image, it is possible to obtain a clear and defect-free image due to extremely stable gas discharge.

[Brief description of the drawings]

FIG. 1 is a process diagram showing an example of a component manufacturing process of an AC type color plasma display of the present invention, wherein (a) is a process diagram of a rear glass substrate, (c) is a process diagram of a thin glass plate of the present invention, and (d). () Is a process drawing of the front glass substrate.

FIGS. 2A and 2B are process diagrams showing an example of a component manufacturing process of a conventional AC type color plasma display. FIG. 2A is a process diagram of a rear glass substrate, and FIG. 2B is a process diagram of a front glass substrate according to a conventional method.

FIG. 3 is a process diagram showing an example of a panel assembling and manufacturing process of a conventional AC type color plasma display.

FIG. 4 is a process diagram showing an example (Example 1) of a panel assembly manufacturing process of the AC type color plasma display of the present invention.

FIG. 5 is a process chart showing another example (Example 2) of the panel assembly manufacturing process of the AC type color plasma display of the present invention.

FIG. 6 is a conceptual diagram for explaining a panel structure of a conventional three-electrode surface discharge type AC color plasma display.
Only pixels are shown. (A) is sectional drawing of a panel,
(B) is a front view of the screen.

FIG. 7 is a conceptual diagram for explaining a panel structure (Example 1) of a three-electrode surface discharge type AC color plasma display of the present invention, showing only one pixel. (A) is sectional drawing of a panel, (b) is a front view of a screen.

FIG. 8 is a conceptual diagram for explaining a panel structure (Example 2) of another three-electrode surface discharge type AC color plasma display of the present invention, showing only one pixel. (A) is sectional drawing of a panel, (b) is a front view of a screen.

FIG. 9 is an explanatory view showing a part of a part A of the present invention, and (a).
Is a front view of the component A, and (b) is a cross-sectional view taken along line XX '.

FIG. 10 is an explanatory view showing a part of a part C of the present invention;
(A) is a front view of part C, (b) is a line segment XX '
FIG.

11A and 11B are explanatory views showing a part of a part D (Example 1) of the present invention, wherein FIG. 11A is a front view of the part D, and FIG. 11B is a cross-sectional view taken along a line XX ′. .

FIG. 12 is an explanatory view showing a part of another component D (Example 2) of the present invention, wherein (a) is a front view of another component D;
(B) is a sectional view taken along line XX '.

13A and 13B are explanatory views of a panel according to the present invention after completion of the panel, in which FIG. 13A is a front view, FIG. 13B shows a single cell of the panel, and FIG. 13C shows a unit pixel.

[Explanation of symbols]

 10 ‥‥ back glass substrate 12 ‥‥ address electrode 13 ‥‥ rib, rib top 13 '‥ rib, black rib top 14 ‥‥ phosphor 14R ‥ red light emitting phosphor 14B ‥ blue light emitting phosphor 14G ‥ green light emitting fluorescent Body 20 glass thin plate 21 protective film, MgO protective film 32 low melting glass 40 front glass substrate 41 transparent conductive film for display, transparent conductive film ITO 42 bus electrode, Cr / Cu / Cr layer 43 Black stripe 44 Transparent dielectric layer, low melting point PbO-based glass layer 50 Discharge gas 51 Discharge cell 70 Display electrode pair 71 Transparent conductive film for electromagnetic wave shielding 72防止 Anti-reflective coating

Claims (5)

[Claims] 1. An address electrode, a rib,
In an AC plasma display panel in which a phosphor is provided, and a display electrode pair is arranged via a dielectric having a protective film in opposition to the phosphor, a thin glass plate having a protective film formed thereon is used as the dielectric having the protective film. An AC type plasma display panel characterized by the above-mentioned. 2. The AC type plasma display panel according to claim 1, wherein a colored glass is used as the glass thin plate. 3. The AC type plasma display panel according to claim 1, wherein a plurality of glasses are used as said glass thin plate. 4. The AC plasma display panel according to claim 1, wherein the dielectric thin glass plate on which the protective film is formed is combined with the ribs on the rear glass substrate on which the address electrodes, the ribs, and the phosphors are formed. And a front glass substrate on which a pair of display electrodes are formed, sealing the whole with low-melting glass, and filling the panel with a discharge gas to form a panel. . 5. The AC plasma display panel according to claim 1, wherein the dielectric thin glass plate on which the protective film is formed is combined with the ribs on the rear glass substrate on which the address electrodes, the ribs, and the phosphors are formed. A panel is formed by adhering and sealing with a low-melting glass, filling with a discharge gas, and bonding the thin glass plate and a front glass substrate on which a display electrode pair is formed with an adhesive.
A method for manufacturing a C-type plasma display.