JPH04163835A - Fluorescent character display tube - Google Patents

Abstract

PURPOSE:To prevent the drop of the brightness including that at the initial period and preclude dispersion in the brightness by adding Au powder to a self-activating Zn oxide fluorescent substance, and thereby forming a fluorescent substance layer. CONSTITUTION:0.01-10wt.% Au powder is added to a self-activating Zn oxide fluorescent substance, and the result is kneaded with a binder for printing. The resultant is applied to an anode conductor 4 to provide a fluorescent substance layer 3, which is subjected to a baking process in the air at a specified temp. to accomplish an anode base board 7. Thus addition of Au powder to self-activating Zn oxide fluorescent substance prevents drop of the brightness including that in the initial period, and also precludes dispersion in the brightness. The Au powder to be added shall preferably have the max. particle size no more than 4.0mum and have a mean particle size of 1.5mum or less.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a fluorescent display tube, and in particular uses a self-activated zinc oxide phosphor as a phosphor, and reduces the brightness of the self-activated zinc oxide phosphor and reduces the brightness. This invention relates to a fluorescent display tube that prevents variations.

[Conventional technology]

Conventionally, self-activated zinc oxide (ZnO:
Phosphors (denoted as Zn) are widely used.

In particular, fluorescent display tubes for automobiles that require high-brightness display have recently become widespread, and ZnO:Zn phosphors have become indispensable for these.

[Problem to be solved by the invention]

However, the above-mentioned ZnO:Zn phosphor
O, Co2. Strong gas adsorption to Co, H2, etc.
In the manufacturing process of the phosphor itself and the manufacturing process of the fluorescent display tube, the extreme surface tends to change in quality due to the heat treatment process (calcination, exhaust, etc.) in which the various residues mentioned above are adsorbed. there were.

By the way, in the light emission phenomenon caused by low-speed electron beam excitation of 200V or less, such as in a fluorescent display tube, the penetration depth of electrons into the phosphor is shallower than in high-speed electron beam excitation such as in a CRT. Sensitive to changes in state. That is, Z
The initial brightness of nO:Zn phosphors tends to fluctuate due to the above-mentioned surface deterioration, and the emission brightness lifetime characteristics are also affected.

In order to prevent this problem, attempts have been made to form a trace amount (~0.1 wt%) of a 5i02 layer on the surface of the ZnO:Zn phosphor or to add 0.1 to 50 wt% of WOh. However, the addition of these additives has the disadvantage that the initial brightness is reduced by 10% or more compared to a fluorescent display tube without additives.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fluorescent display tube that is free from deterioration and variation in initial brightness and has good emission brightness lifetime characteristics.

[Means to solve the problem]

The present invention provides a fluorescent display tube having an anode on which a phosphor layer is formed and a cathode that emits electrons, in which the phosphor layer includes a self-activated zinc oxide phosphor containing Au powder in an amount of 0801 to 10 wt.
% added.

The maximum particle size of the Au powder is 40 μm or less, and the average particle size is 1.5 μm or less.

Mouth Example] Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a main part of a first embodiment of the invention, and FIG. 2 is a partial sectional view of a phosphor layer of the first embodiment of the invention.

As shown in FIG. 2, the phosphor layer of the first embodiment is made of ZnO with an average particle diameter of 4 μm: Zn phosphor 1 with an average particle diameter of 1 μm.
, 0 μm Au powder 2 was mixed with 0.2 wt%, this was kneaded with a printing binder containing ethyl cellulose as a resin component, and this was applied onto the anode conductor 4 shown in FIG. 1 by screen printing method, An anode substrate 7 is obtained through a baking process in the air at about 500°C. By passing this through a normal fluorescent display tube manufacturing process, a fluorescent display tube of the first example was obtained.

Initial brightness and 100°C of fluorescent display tube according to the first embodiment
Table 1 shows a comparison of the operating characteristics with conventional fluorescent display tubes.

Table 1 As shown in Table 1, the fluorescent display tube of the first embodiment had no decrease in initial brightness, and had the effect of significantly improving both the initial brightness variation and the rate of decrease compared to the conventional fluorescent display tube. Ta.

FIG. 3 is a partial cross-sectional view of a phosphor layer according to a second embodiment of the present invention.

As shown in FIG. 3, the phosphor layer of the second embodiment includes ZnO with an average particle size of 4 μm: Zn phosphor 1 with an average particle size of 1.0 μm.
0.2 wt% of 5 μm flaky Au powder 21 was mixed and kneaded with a printing binder containing ethyl cellulose as a resin component, and this was screen printed as in the first embodiment to form the anode shown in FIG. Apply on conductor 4 and apply about 50
An anode substrate 7 is obtained through a baking process in the air at 0°C. By passing this through a normal fluorescent display tube manufacturing process, a fluorescent display tube of the second example was obtained.

The initial brightness, initial brightness variation, and 100° C. operating characteristics of the thus obtained fluorescent display tube were similar to those of the first example.

There are Au powders with various particle size distributions,
The maximum particle size is 4.0 μm or less, and the average particle size is 1.
If the thickness was 5 μm or less, the above-mentioned effect could be obtained.

In addition, ZnO: The method of mixing Zn phosphor and Au powder is
nO: Any method may be used as long as it does not damage the Zn phosphor particles and can uniformly disperse them, and is not particularly limited.

Furthermore, since the same effect can be obtained in a flat-emitting type fluorescent display tube in which the display is observed through a transparent electrode on a transparent anode substrate, the present invention is limited to the fluorescent display tube having the structure shown in this example. It's not a thing.

〔Effect of the invention〕

This has the effect of preventing a decrease in the included brightness and preventing variations in brightness.

[Brief explanation of drawings]

FIG. 1 is a sectional view of essential parts of a first embodiment of the invention, FIG. 2 is a partial sectional view of a phosphor layer of the first embodiment of the invention, and FIG. 3 is a sectional view of a second embodiment of the invention. FIG. 3 is a partial cross-sectional view of an example phosphor layer. 1...ZnO: Zn phosphor, 2,21...
... Au powder, 3 ... Phosphor layer, 4 ... Anode conductor, 5 ... Power supply wiring layer, 6 ... Insulating layer, 7 ... - Anode substrate, 8... Grid, 9... Filament, 10... Cover glass. Agent Patent Attorney Otosen Uchihara Figure 1, Figure 2, Appendix 3

Claims (2)

[Claims] 1. In a fluorescent display tube having an anode on which a phosphor layer is formed and a cathode that emits electrons, the phosphor layer is a self-activated zinc oxide phosphor with 0.01 to 10 wt% of Au powder added. Features a fluorescent display tube. 2. 2. The fluorescent display tube according to claim 1, wherein the Au powder has a maximum particle size of 4.0 μm or less and an average particle size of 1.5 μm or less.