JPH01292729A - Gas discharge display device - Google Patents

Abstract

PURPOSE:To improve the workability and the productivity of a thin plate of inorganic insulating material used for the constitution of gas discharge spaces by forming micro discharge spaces in the said plate with mechanical processes. CONSTITUTION:A ceramic thin plate in a mechanically workable state is proceed mechanically in high speed and high dimensional accuracy to make holes for micro discharge spaces in the said plate. For making holes mechanically in high speed and high dimensional accuracy, punching process or ultrasonic process able to form multiple processing jigs are suitable. As for mechanically workable inorganic insulating material ceramics before sintering, ceramics in incompletely solidified pre-sintered state, of glass precipitated with special crystals are suitable. Thereby insulating ceramic plate of high dimensional accuracy holes, of arbitrary variable hole pitches, of large area and thickness can be manufactured in high speed and high productivity to improve the quality and to reduce the cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gas discharge display device, and particularly to a full-color gas discharge display device suitable for high resolution, high brightness, and a large screen.

[Conventional technology]

Gas discharge display devices ionize the filled gas in a discharge space and display information using the light emitted by the ionized gas itself or the fluorescence generated when a phosphor is irradiated with ultraviolet rays or electrons excited by the ionized gas. .

Therefore, in improving the performance of gas discharge display devices and manufacturing them using Indium, the technology for manufacturing the discharge space plays an important role.

FIG. 1 is a schematic cross-sectional view of a gas discharge display device that utilizes light emission from a phosphor. This device has a structure in which discharge cells 1 are arranged in a matrix with partition walls 2 interposed between them, and are sandwiched between a face plate 4 on which an anode 6 is formed and a substrate 5 on which a cathode 7 is formed. The inner surface of the discharge cell 1 is coated with a phosphor 3. The circumference of the discharge cell 1 is hermetically sealed, and Xs, Ne, or a mixture thereof is sealed as a discharge gas inside.

In this type of gas discharge display device, a voltage is applied between the anode 6 and the cathode +@7 to generate ultraviolet rays in the discharge gas, thereby displaying the fluorescence emitted from the phosphor as information.

There is also a gas discharge display device that does not coat the surface of the partition wall 2 with a phosphor and displays information simply by emitting light from discharge gas.

As is clear from the above description, in a gas discharge display device, the display brightness and resolution and image quality largely depend on the quality of the shape of the discharge cells. That is, in gas discharge display devices, the manufacturing technology of the discharge cells occupies an important position. Especially in high-definition full-color gas discharge televisions,
Since a large screen, high brightness, and high resolution are required, highly accurate discharge cell formation technology is required.

For example, assuming the structure of the discharge cell of a 40-inch full-color gas discharge television, the shape of the discharge cell with sufficient brightness for practical use is about 0.8 m square and 1.8 m deep.
5~2I11! ! It is a rectangular parallelepiped space, and the overall structure of the television is as follows: 480 discharge cells in the vertical direction;
800 cells are arranged horizontally.

In addition, this number of cells is for images in the current NTS C standard mode, but it is for IDT images that will be put into practical use in the future.
In V, EDTV, and HDTV, there is a strong demand for higher precision in response to miniaturization and an increase in the number of discharge cells. It holds the key to the practical application of television.

The discharge cells of conventional gas discharge display devices are formed by the following three methods.

The first method is to make a through hole in a discharge cell forming material such as an insulating glass plate by chemical etching and use this hole as a discharge cell. In this method, the cross-sectional shape of the hole is irregular because of the well-known side etch phenomenon. Alternatively, there have been problems such as low dimensional accuracy of the hole and a large difference in hole diameter between the hole entrance and the center.

In order to operate a gas discharge display device with a long life, a discharge cell with a deep hole is required, but it is almost impossible to form a deep hole in a thick plate by the above-mentioned method due to dimensional accuracy. Therefore, in order to obtain a thick plate with deep holes formed with good dimensional accuracy using the chemical etching method, it is necessary to first drill holes in a thin plate of about 0.2 to 0.3 nm and then stack and weld multiple sheets. This has been a major obstacle in manufacturing long-life discharge cells.

The second method is to melt a part of the flat plate material by irradiating it with a laser beam or the like, and then drill the hole while blowing away the melted material. In this method, a part of the material is heated above its melting point, so there are problems such as significant deterioration of the material around the hole and molten matter adhering to the area around the hole.

Also, as with the chemical etching method, due to processing, there is a large difference in hole diameter on the bottom surface, and this is almost proportional to the thickness of the material, so it was not possible to form holes with high accuracy in a flat plate of approximately 2+In. . Furthermore, this method requires a long machining time because it is difficult to simultaneously drill a large number of holes using multi-beams.
It is not suitable for forming discharge cells in a large-area gas discharge display device, such as a 0-inch television, which has approximately several hundred thousand discharge cells.

The third method is to form partition walls on a flat plate of material using a thick film printing method. This method is a method in which the same pattern as the discharge cells of a gas discharge display device is printed on a flat glass plate using a glass paste serving as a barrier rib material through a printing screen.

- The height of the printed film thickness that can be formed in one printing is 0.01~
Since the height is very low at around 0.02 m, there is a problem in that in order to obtain a partition wall with a large height, it is necessary to print an extremely large number of times.1 For example, in a discharge space with a partition wall 1.5 m high, In order to make.

The number of printings will be as many as 100 times. In the printing method,
There are fundamental problems in ensuring print pattern accuracy, such as printing paste bleeding, printing sag, and misalignment. This problem naturally becomes more serious as the number of times of printing increases, so it has been extremely difficult to form discharge cells with high precision by screen printing. Further, when the printed partition walls are fired and solidified in a post-process, the paste forming the partition walls shrinks, which also poses a problem in terms of dimensional accuracy.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not give sufficient consideration as a technology for forming discharge cells of a gas discharge display device such as a full-color television, and a large screen.

Machinability is essential for producing discharge cells with high dimensional accuracy for high brightness, long life, high resolution, and good image quality.

There were problems in terms of productivity.

An object of the present invention is to provide a gas discharge display device having a discharge cell that achieves high brightness, long life, and high resolution by solving the problems of the prior art described above. Another object is to improve the productivity of the gas discharge display device and provide it at a low price.

[Means to solve the problem]

The above object is achieved by mechanically drilling holes in a thin ceramic plate that is ready for machining at high speed and with high dimensional accuracy.

However, since ceramics are generally hard, it is almost impossible to drill holes using normal machining.

Ceramics before being completely densified, i.e. ceramic green sheets and calcined ceramic sheets, are
Normal machining is possible. Also.

7'/ mica glass or YxOa -Ca O-A (i
The zoa-8iOz-based crystallized glass is dense and machinable. Ceramic green sheets are made into a material for forming gas discharge spaces by being densified and sintered after drilling holes, and calcined ceramic sheets are used after drilling holes and coating or impregnating them with glass or the like.

On the other hand, punching and ultrasonic machining, which can form multiple processing jigs, are suitable for mechanically drilling holes at high speed and with high dimensional accuracy, and are used to drill holes in the ceramics.

[Effect]

As the inorganic insulating material that can be machined, suitable materials include ceramics before sintering, that is, ceramics that have not yet solidified in a pre-sintered state, or glass on which special crystals have been precipitated, as described above. These machinable ceramics can be processed using conventional machining tool materials such as die steel, high speed steel, or cemented carbide. Conventional ceramics that have been completely densified and sintered cannot be processed without expensive tools such as diamonds because they are extremely hard, and tools made of normal materials cause a lot of wear during processing. This is because it cannot be processed with high precision and at a practical level.

Since the hardness of the aforementioned machinable ceramics is lower than that of ordinary tool materials, there are almost no problems such as tool wear. In addition, when looking at the processing mechanism of machinable ceramics using punches and ultrasonic processing tools, processing progresses as fine particles of several micrometers or less that make up the ceramic are removed from the base material by processing energy. , the machining stress on both the workpiece and the tool is extremely small. Therefore, it is possible to use a drilling device with multiple processing tools,
Capable of drilling holes in large area ceramic sheets at high speed. Furthermore, since the processing accuracy is almost determined by the size of the fine particles that make up the ceramic, finishing accuracy on the order of several μm can be expected. This accuracy indicates extremely high accuracy when the diameter of the discharge space of the gas discharge cell is 1 m.

As described above, the present invention is characterized in that by utilizing the unique machinability of machinable ceramics, machining is performed using ordinary materials and multi-type machining tools at high speed.

〔Example〕

Examples of the present invention will be described in detail below.

[Example 1] Sio2. Fluorine-based mica glass containing AQzOs, MgO, KzO, F, etc. as a component is a crystallized glass in which fluorine-phlogopite and aluminosilicate glass are placed in approximately equal positions, and machining is difficult due to the presence of fluorine-phlogopite. It is known as a type of machinable ceramic.

FIG. 2 is an explanatory diagram of the present invention in which a large number of fine holes are simultaneously formed in this machinable ceramic plate by ultrasonic processing. In FIG. 2, 2000 thin ultrasonic horns 12 are attached to the tip of an ultrasonic tool 11. The material of this horn is high speed steel, 1m x 0.8
mm + length 15I Next, a back-up material 14 is laid on the vertically and horizontally movable stage 15, and the machinable ceramics 13 with a thickness of 2 m and 10100 x 100 is fixed on top of it, and from above, Pressing the ultrasonic horn 12 operated by the ultrasonic oscillator 16,
Ultrasonic machining is performed with a slurry of QzOa abrasive grains, and 2,000 1 m square holes are formed in the machinable ceramic plate 3 in a machining time of about 5 minutes. Next, the stage 15 is moved in the horizontal direction, and a similar hole is drilled at another location on the machinable ceramic. By performing ultrasonic machining four times in this manner, 8,000 holes are formed on the entire surface of the IQO square, 2 m thick machinable ceramic.

The dimensions of this hole and the accuracy of the hole pitch depend on the accuracy of the ultrasonic horn, but since this horn is made of metal, it is easy to perform high-precision machining. Naturally, the dimensional accuracy is also very good. Also,
Since the length of the horn can be changed freely, it is easier to drill holes in ceramics that are thicker than in this embodiment. Furthermore, since the number of horns can be changed arbitrarily, a large number of holes can be formed at the same time, making it possible to speed up hole formation.

When forming a hole in a large area of machinable ceramics, for example, it is possible to form a hole with a length equivalent to one side of the workpiece machinable ceramics without using the ultrasonic tool 11 with approximately the same vertical and horizontal dimensions as shown in FIG. By using horns arranged in several rows and sequentially moving the stage 14 on which the workpiece is placed, a hole can be formed in the material with an area corresponding to the moving distance.

As described above, according to the present invention, fine holes can be formed in large-area plates with high dimensional accuracy and at almost any depth.

Can be formed at high speed.

[Example 2] 92wt% fine AQzOs powder and sintering aid powder (AQx
Appropriate amounts of an organic binder such as polyvinyl butyral and a solvent such as trichlorethylene are added to a mixed powder having a composition of 8 wt% (Os, SiOz, MgO), and after thoroughly mixing these, the thickness is 2IIIm
Create a green sheet. This green sheet has high machinability because the inorganic ceramic powder is bonded with organic matter.

FIG. 3 is an explanatory diagram according to the present invention for forming a large number of fine holes in the green sheet at high speed by pump punching. In FIG. 3, the upper die 41 has a diameter of 1 mm.
500 +m tool steel punches 42 are attached, and corresponding punch holes 44 are formed in the lower die 43. A green sheet 45 as a workpiece is set between the upper and lower dies, and as the upper die 41 descends, a hole is made in the green sheet. By moving the green sheet in the horizontal direction, it is possible to drill holes in a large area of the green sheet at any desired pitch.

Heat the green sheet with holes to 1580℃.

When heated in air for 1 hour, the organic binder in the green sheet evaporates and the green sheet shrinks by about 15%, becoming a completely dense perforated sintered plate. The perforated plate of alumina ceramics is
Both the hole diameter and hole pitch are suitable as a discharge space for a gas discharge display device. Also, with multi-punch, 100 hits/
Since it can be processed at a speed of 1 minute, it is possible to perform high-speed hole processing on large-area plates.

[Example 3] The alumina green sheet used in Example 2 was
'C, a calcined ceramic plate is obtained by heating in air for 1 hour. Since this calcined body is not yet sufficiently densified, the bond between the inorganic powders constituting the calcined body is not very strong, so that machining is easy.

As in Example 1, this calcined ceramic sheet was set in the ultrasonic processing apparatus shown in Fig. 2, and the applied power was 1.2 KW.
Holes were drilled at a feed rate of 0.1 m/min. As a result, 1m
2000 holes were formed in a calcined ceramic plate with a diameter of 501 m. This calcined ceramic plate is not sufficiently densified and is therefore slightly porous, with approximately 35% pores in the calcined body.

Therefore, this perforated calcined ceramic plate was immersed in molten glass maintained at ttoo°C, and a treatment was performed to allow the glass to penetrate into the pores in the calcined ceramic plate.

Through this treatment, the calcined ceramic plate becomes airtight and functions as a discharge space for a gas discharge display device. In this embodiment, an example of an alumina calcined body is shown as the workpiece material, but it goes without saying that the same effect can be achieved by using porous machinable ceramics, glass, or the like.

〔Effect of the invention〕

As described above, according to the present invention, the dimensional accuracy of the holes is good, the hole pitch can be changed arbitrarily, and insulating ceramic plates with large areas and large thickness can be manufactured quickly and with high productivity. , the effects of improving the quality and reducing the cost of the discharge space for gas discharge display devices are significant.

The effects of the present invention are not limited only to the discharge space of the gas discharge display device, but also have a great effect on the formation of through holes in multilayer ceramic circuit boards. That is, the holes of the perforated machinable ceramic shown in Example 1 were filled with a conductive metal used for one circuit board,
Furthermore, by layering a plurality of these after wiring in a planar direction, a multilayer circuit board with three-dimensional wiring can be manufactured with high dimensional accuracy and a large area.

[Brief Description of the Drawings] Figure 1 is a schematic cross-sectional view of a gas discharge display device, Figure 2 is an explanatory diagram of an embodiment of discharge space formation according to the present invention, and Figure 3 is a schematic diagram of discharge space formation according to the present invention. It is a diagram. DESCRIPTION OF SYMBOLS 1... Discharge cell, 2... Partition wall, 3... Fluorescent material, 4
. . . Face plate, 5. Substrate, 6. anode, 7... cathode,
11... Ultrasonic tool, 12... Horn, 13...
Machinable ceramics, 14...backup material,
15... stage, 16... ultrasonic oscillator, 41...
... Upper die, 42... Punch, 43... Lower die, 44.
...Drilling hole, 45...Work material. 1st figure 1 Zokudenbeguru 4th level grade 5 base plate 6 Yogoku 7 wall ground figure 2 (illustration lL5.flF7 [7 e.

Claims (1)

[Scope of Claims] 1. Ionization of the filled gas in the discharge space and emission of light by the ionized gas itself, or by fluorescence generated when a fluorescent body is irradiated with ultraviolet rays or electrons generated by the ionized gas. A gas discharge display device for displaying information by using an inorganic insulating material for forming the gas discharge space, and having a fine discharge space formed by machining a thin plate of the material. Display device. 2. The gas discharge display device according to claim 1, wherein airtight machinable ceramics are used as the inorganic insulating material. 3. A discharge space formed by using porous machinable ceramics as the inorganic insulating material, machining it to form a fine discharge space, and impregnating or coating the surface with an inorganic insulating material. The gas discharge display device according to claim 1, characterized in that it has: 4. The gas discharge display device according to claim 1, further comprising a discharge space of the inorganic insulating material formed by ultrasonic machining. 5. The gas discharge display device according to claim 1, further comprising a discharge space of the inorganic insulating material formed by punching. 6. The gas discharge display device according to claim 2, wherein a sintered body containing fluorine phlogopite as a main component or crystallized glass is used as the airtight machinable ceramic. 7. The gas discharge display device according to claim 3, wherein a ceramic calcined body or porous glass is used as the porous machinable ceramic. 8. A claim characterized in that a ceramic green sheet is used as the inorganic insulating material, the fine discharge space is formed by machining the same, and the discharge space is formed by sintering the green sheet. Item 1. Gas discharge display device according to item 1.