JPH0246638A - Fluorescent character display tube - Google Patents

Abstract

PURPOSE:To prevent the diffusion of alkaline component from the transparent insulating substrate to the phosphor and the drop of the effective anode potential of the phosphor so as to improve the luminance characteristics by providing phosphor on two layer consisting of transparent electro-conductive oxide film and conductive metalic film. CONSTITUTION:A fluorescent character display tube is constructed with a transparent substrate 1 and electrode layer provided on which consisting of the 1st layer of transparent electro-conductive oxide film 7 of 1000-10000Angstrom in thickness and the 2nd layer of conductive metalic film 2 of 200-1000Angstrom in thickness and phosphor layer 4 provided on the electrode layer. Thereby the diffusion of alkaline component from the transparent substrate 1 to the phosphor can be prevented, and as the phosphor 4 is contacted to the conductive metallic layer 2 the drop of the effective anode voltage is small, so that the luminance characteristics can be improved in contrast with a conventional tube.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fluorescent display tube, and more particularly to an electrode structure of a flat-emitting fluorescent display tube in which a display is observed from the opposite side of an electrode-forming substrate.

[Conventional technology]

Conventionally, an example of this type of flat-emitting type fluorescent display tube, as shown in FIG. Thereafter, metal electrodes 2a and 2b are formed using a technique such as photolithography so as to obtain a desired pattern.

In this case, the metal electrodes 2blC of the display section are usually formed in a honeycomb structure or stripe structure so that the light emitting display can be efficiently extracted from the observation surface (lower surface) side pressure.

Thereafter, in order to make the display clearer, an insulating layer 3 is formed on the metal electrode 2a using a technique such as printing.

Next, the phosphor 4 is formed on the metal electrode 2b of the display section using a similar method.

The grid 5 and the filament 6 are constructed as shown in FIG. 2, and the entire structure is vacuum-sealed to complete the fluorescent display tube.

In the fluorescent display tube manufactured by heating in this manner, when the filament 6 is heated to about 600°C to 650°C, the carbon dioxide is taken out, which is accelerated by the grid 5.
By colliding with the phosphor 4, a luminescent display was obtained.

[Problem to be solved by the invention]

Since the conventional fluorescent display tube described above has a structure in which the phosphor 4 is in contact with the light-transmitting insulating substrate 1, it has the following drawbacks.

That is, the light-transmitting insulating substrate 1 is usually made of a low-priced plate glass from a cost perspective, and the phosphor 4 that is in direct contact with alkaline components such as sodium and potassium contained in the plate glass is used as the light-transmitting insulating substrate 1.
There is a drawback that the phosphor 4 deteriorates due to interaction with the phosphor.

In addition, in the manufacturing process of a fluorescent display tube, the metal electrode 2a and the insulating layer 3 interact with each other especially at high temperatures of 500°C to 600°C, so the thickness of the metal electrode 2a must be The required value is 1/Jm or more. For this reason,
In a flat-emitting type fluorescent display tube in which the display is observed from the opposite side of the transparent insulating substrate 1 from which the electrodes are formed, there is a drawback that the display quality is poor due to reflection from the metal electrode 2a.

In order to eliminate the above-mentioned drawbacks, a fluorescent display tube using a translucent oxide conductive electrode 7 is also used, as shown on the other side of the conventional one in FIG. There are drawbacks. That is, in this fluorescent display tube, the transparent oxide conductive electrode 7, which is a semiconductor, and the phosphor 4 are in contact with each other, and compared to the structure shown in FIG. The drawback is that the anode voltage is lowered and the brightness is lowered. This tendency is particularly noticeable in KZnOiZn-based phosphors, and compared to the structure in Fig. 2, the structure in Fig. 3 has a luminance of 3
0% to 50% lower.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fluorescent display tube in which the above-mentioned drawbacks are solved and the display quality is not degraded and the brightness is not degraded.

[Means to solve the problem]

The structure of the present invention is to form a display pattern by coating a phosphor on an electrode on a translucent substrate constituting an airtight container, and to make the phosphor emit light by bombarding the phosphor with electrons emitted from a filament. In a fluorescent display tube in which the display is observed from the surface opposite to the surface on which the electrodes are formed on a transparent substrate, the first layer of the electrode is a transparent oxide conductive film, and the second layer above this is a transparent conductive oxide film. It is characterized in that it is formed of a metal conductive film, and the phosphor is formed on the metal conductive film.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a sectional view showing the substrate, grid, and filament portions of a fluorescent display tube according to a first embodiment of the present invention. In the figure, the fluorescent display tube of this embodiment has a light-transmitting insulating substrate 1 made of plate glass, a light-transmitting oxide conductive film of ITO film of 200 OA on its main surface, and a metal conductive film. The A1 film was formed using a 500A vapor deposition method.

Next, in order to obtain a desired pattern or display, a photolithography technique ζ consisting of steps of photoresist application, exposure and etching was used (thereby, a transparent oxide electrode 7 and a metal electrode 2 were formed).

Next, the insulating layer 3 is applied to the area other than the display area using a printing method.
It was formed by a thermal process at .degree. C., and the phosphor 4 was also formed by the same method. Grid 6, filament 7 sequentially,
It was formed to maintain a predetermined distance from the phosphor screen, and the whole was sealed in vacuum to produce a phosphor display tube.

Next, a fluorescent display tube according to a second embodiment of the present invention will be described.

The second example is similar to the first example, except that a 5n02 film with a thickness of 4000A is used as the transparent oxide conductive film, and the second example is similar to the first example. A fluorescent display tube was produced in the same manner as in the example.

Next, a fluorescent display tube according to a third embodiment of the present invention will be described. The third embodiment differs from the first embodiment in that an 8000A thick ITO film is used as the transparent oxide conductive film, and an 800A thick Au film is used as the metal conductive film. A fluorescent display tube was fabricated in the same manner as described above.

These f41. Second. When we investigated the brightness characteristics of the fluorescent display tube manufactured in the third example, we found that compared to conventional fluorescent display tubes, the brightness of the ZnO:Zn-based phosphor was 10 to 20%
, °Cd) A 20-30% increase in brightness was confirmed for all SiAg-based phosphors.

In the fluorescent display tubes of these embodiments, the electrode on the transparent substrate 1 has a first layer of 100OA to 10,000 to 100
Since it has a structure in which it is formed with a 0A metal conductive film and then a phosphor is formed, it is possible to prevent the alkali component from diffusing from the light-transmitting substrate to the phosphor, and it is also possible to prevent the diffusion of alkaline components from the light-transmitting substrate into the phosphor. Since they are in contact with each other, there is little drop in the effective anode potential.
Therefore, compared to conventional fluorescent display tubes, brightness characteristics can be improved.

Furthermore, since the fluorescent display tube of this example has a two-layer structure consisting of a light-transmitting oxide conductive film and a metal conductive film as described above, the metal conductive film is Even if the insulating film and the insulating film interact, electrical continuity can be ensured by the underlying transparent oxide conductive film.

Therefore, the thickness of the metal conductive film can be made as thin as 20 OA to 1000 Å, and reflection by the metal conductive film can be eliminated, making it possible to provide a fluorescent display tube with excellent display quality.

Note that the thickness of the transparent oxide conductive film is 100OA to 1
A range of 0000A is most preferred for practical purposes; if the thickness is thinner than this range, it will be difficult to ensure electrical continuity, and if it is thicker than this range, the efficiency of emitting the light emitting display to the viewing surface will be poor. becomes worse and is not practical.

Similarly, the thickness of the metal conductive film is 200A to 100A.
A range of 0A is practical and preferred.

〔Effect of the invention〕

As explained above, the present invention provides a transparent oxide conductive film,
By forming the phosphor on the two-layer structure of the metal conductive film, it is possible to prevent the diffusion of alkaline components from the light-transmitting insulating substrate (plate glass) into the phosphor and to change the effective anode potential of the phosphor. This has the effect of preventing the decrease in brightness and improving the brightness characteristics.

Further, in the present invention, since the thickness of the metal conductive film can be made as thin as 200A to 1000A, there is no reflection due to the metal conduction film, and the display quality is excellent.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an anode substrate grid and filament of a fluorescent display tube according to a first embodiment of the present invention, and FIGS. 2 and 3 are cross-sectional views of a conventional fluorescent display tube. 1... Translucent insulating substrate, 2, 2a...
Metal electrode, 2b...Metal electrode of display section, 3. Old... Insulating layer, 4... Phosphor, 5... Grid, 6... Filament, 7...
Transparent oxide electrode. Agent: Patent Attorney Uchihara Shinshu

Claims (1)

[Claims] A display pattern is formed by coating a phosphor on an electrode on a translucent substrate constituting an airtight container, and electrons emitted from a filament are applied to the phosphor to cause it to emit light. In a fluorescent display tube in which the display is observed from the surface opposite to the surface on which the electrode is formed, the first layer of the electrode is formed of a transparent oxide conductive film, and the second layer thereon is formed of a metal conductive film. ,
A fluorescent display tube, characterized in that the phosphor is formed on a pre-metallic conductive film.