JPS6084747A - Fluorescent character display tube - Google Patents

Abstract

PURPOSE:To maintain the internal atmosphere of the airtight case at a high level vacuum so as to prevent any deterioration of the luminance of a fluorescent character display tube by absorbing the residual gas existing in the case by active alumina placed in at least a part of the case. CONSTITUTION:In a fluorescent character display tube, electrons discharged from a cathode 29 reach an anode 25 after passing through a mesh-like control electrode 28 and a part of the electrons stimulate a phosphor 26 to cause it to emit light. When making such a fluorescent character display tube, an anode feeder 22 is printed on a base plate 21 by silver wiring before a black insulating layer 24 is formed on the anode feeder 22. Next, an anode 25 is formed on the back insulating layer 24. At the same time, a mixture solution composed of 10wt% of active alumina and 90wt% of 3% dilute acetic acid is applied to the surface of the insulating layer 24 by spraying to form an active alumina layer 27. As a result, it is possible to maintain a high level vacuum by absorbing the residual gas existing in a vacuum case by active alumina. Accordingly, it is possible to extend the life of the display tube by preventing any deterioration of its luminance.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention allows electrons emitted from a cathode to collide with an anode having a phosphor layer on a four-body layer in a vacuum-tight container, thereby displaying desired characters, numbers, symbols, etc. This invention relates to a fluorescent display tube for displaying.

Conventionally, the basic structure of a fluorescent display tube is known, for example, the structure shown in FIG. Some are placed on the same plane as the anode)vi-
A part of the electrons passing through the anode 13 stimulates the phosphor 14t to emit light.

However, since the graphite material used to form the conductor layer such as the anode 13 has a significantly large amount of adsorbed gas, it is difficult to perform sufficient degassing during the product manufacturing process. It had a negative effect on the characteristics.

The object of the present invention is to provide a highly reliable fluorescent display tube that overcomes all of the above-mentioned disadvantages.

That is, by arranging activated alumina in at least a part of the airtight container of the fluorescent display tube, the 0. This activated alumina adsorbs residual gas inside the fluorescent display tube.

The present invention not only provides a fluorescent display tube that exhibits absorbing behavior and has a high degree of vacuum, but also maintains a high density.As a result, the luminance Deterioration has been greatly improved, and lifespan has also been greatly extended.

Hereinafter, embodiments of a fluorescent display tube according to the invention will be described.

Figure 1 shows the anode part of the substrate according to the present invention. On the anode substrate 21, an anode power supply line 22 is printed with silver wiring, and then baked, a black insulating layer 24 is printed through the through hole part 23, and then baked. After.

The activated alumina layer 27 is formed by spraying a mixed bath fL of 10 ωt % of activated alumina and 90 ωt % of 3% dilute acetic acid onto the surface of the insulating layer 240 and firing. Thereafter, a graphite paste is printed and dried to form a four-layer anode 25, and a phosphor 26 is printed thereon and fired to form an anode. After a predetermined mesh-like control grid electrode 28 and cathode 29 are arranged on this anode substrate, the entire combination of cover glasses is sealed with low melting point glass that has been printed around the cover glass and the substrate in advance.

After that, while exhausting the air inside this image light display tube and the gas released from the valley member, the entire original display tube was
By heating to 0.degree. C., sufficient degassing is performed and the activity of the activated alumina layer 27 on the insulating surface on the anode substrate is raised to the same level, followed by sealing. Thereafter, a portion of the cover glass inside the fluorescent display tube is sputtered with Ba getter to form a fluorescent display tube. Conventionally, fluorescent display tubes with an activated alumina layer formed on the insulating surface layer had a brightness deterioration of about 20% after 500 hours, but the prototype bulb produced using this manufacturing method showed a much lower brightness deterioration than before. The condition has been improved to a degree of chi, and the lifespan has been greatly extended.

In the case of Misu Ja, the activated alumina layer was formed on the insulating surface layer of the anode substrate, but if it can be formed on the surface layer of the valley member inside the tube, the same effect can be obtained even on a part of the cover glass. In addition, in the four cases in which the activated alumina layer was formed by dissolving activated alumina in a solution, applying it, and firing it, the same result could be obtained even if activated alumina solids were placed inside the whole pipe. It goes without saying that the effects may vary and be included in the scope of non-claims.

[Brief explanation of drawings]

FIG. 1 is a sectional view illustrating a conventional fluorescent display tube structure, and FIG. 2 is a sectional view illustrating the structure of an anode portion of a fluorescent display tube according to embodiments 1c and 1 of the invention. 11.29...Cathode, 12.28...
Control grid electrode, 13.25...Anode% 14.
26... Fluorescent material, 15.24... Insulating layer, 16.22... Power supply wiring, 17.21...
... Anode substrate, 23 ... Insulating layer through hole part, 2.7 ... Active alumina layer. . Figure 2

Claims (1)

[Claims] In a fluorescent display tube, electrons emitted from a cathode are caused to collide with an anode having a phosphor layer formed on a substrate in an airtight container to display a desired character, letter A, symbol, etc. A fluorescent display tube characterized in that activated alumina is disposed in at least a portion of the container.