JPH01283748A - Fluorescent character display tube - Google Patents

Abstract

PURPOSE:To increase the gas adsorption amount and to prevent the decrease of service life by spreading a B2O3 layer of a specific thickness on the surface of Ni powder so as to prevent the oxidization of the Ni powder which is inevitable in the manufacturing process. CONSTITUTION:A Ni powder to whose surface a B2O3 layer with the thickness 0.1-20mum is spread, and a Ba-Al alloy powder are mixed in a specific ratio, and a pressure is applied to form a getter substance. By spreading and forming the B2O3 layer on the surface of the Ni powder used for a getter substance, the oxidization of the Ni surface in the sealing process of a fluorescent character display tube is prevented and the decrease of Ba evaporation amount owing to the oxidization of the Ni is prevented. As a result, a getter layer of an excellent gas adsorption ability is obtained, and a long service life of fluorescent character display tube can be manufactured.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a fluorescent display tube.

[Conventional technology]

Fluorescent display tubes operate using thermionic radiation from the cathode, so the inside of the envelope is maintained in a vacuum state, and the quality of the vacuum greatly influences the length of its life. Therefore, in order to keep the inside of the display tube always in a high vacuum state, a metal film layer (getter layer) containing Ba as a main component as a gas adsorbing substance is formed in a part of the tube.

Conventionally, this metal film layer mainly composed of Ba was BaA6. A getter material made by mixing metal powder with the composition of Ni powder and press-molding the mixture is heated to Ba
Formed by selective evaporation of During this heating, the Ni powder reacts with An, and the reaction heat evaporates a certain amount of Ba.

[Problem to be solved by the invention]

However, in the manufacturing process of a fluorescent display tube, there is a step in which the getter material is heated to 300° C. or higher in the atmosphere before vacuum sealing. For this reason, the surface of the Ni powder is oxidized, and the reaction between Ni and An does not start in the above-mentioned heating evaporation process, the so-called getter flushing process, and as a result, Ba1t, which evaporates and becomes a gas adsorption layer (getter layer), decreases. .

Therefore, there was a drawback that the amount of gas adsorption decreased and the life span was shortened.

[Differences between the invention and the prior art]

The fluorescent display tube of the present invention uses Ni to prevent the aforementioned oxidation of the Ni powder, which is unavoidable in the manufacturing process of the fluorescent display tube.
B with a thickness of 0.1 to 20 μm on the surface of the powder in advance
The difference is that a tOs layer is deposited.

[Means to solve the problem]

The fluorescent display tube of the present invention consists of Ni powder and Ea powder with a B203 layer deposited on the powder surface having a thickness of 0.1 to 20 μm.
, A1 alloy powder is mixed in a predetermined amount and the mixture is press-molded to form a getter material.

[Example 1] Next, the present invention will be explained with reference to the drawings.

FIG. 1 shows the first embodiment of the present invention. A cross-sectional view of the second embodiment, FIG. 2 is a cross-sectional view of the getter of the present invention. In the first embodiment, an anode substrate is obtained by a conventional manufacturing method in which a conductive layer 3 and a phosphor layer 4 are repeatedly printed and fired as thick films on a glass substrate 5 made of leader lime glass. A so-called electrode part having a grid 2, a cathode 11 getter 10, and a lead terminal 9 on this anode substrate,
Cover glass 7, spacer glass 6 and frit glass 8
to form a vacuum container, then vacuum evacuation,
The interior of the vacuum container is maintained in a vacuum state through a sealing process. Here, the getter 10 includes a getter material 12 formed by pressure molding BaA474 alloy powder and Ni powder with a B2O3 layer of about 2.5 μm thick on the surface, and a ring-shaped getter container serving as a container for the getter material 12. It consists of 13. This getter material 12 is also used in the above-mentioned sealing process.
Since No. 3 covers the surface of the Ni powder, Ni is hardly oxidized. Therefore, even in the heat evaporation step of the getter material after the sealing step, a reaction between N1 and An occurs quickly, and the heat generated by the reaction sufficiently evaporates Ba of the getter material 12, resulting in sufficient gas adsorption capacity. A getter layer 11 is formed.

The fluorescent display tube of the first embodiment is obtained by the method described above. The weight composition ratio of the getter material in the first example is B a
A 424 is 50.8wt%, Ni is 48.9wt%
, B 20 s is 0.3 wt%.

Further, the Ni powder coated with B,03 is obtained by immersing the Ni powder in an alcohol solution in which B2O3 is dissolved and drying it at 150°C or lower.

[Example 2] The second example uses B20 having a thickness of about 20 μm, Ni powder with a layer formed on the surface, and B a A I! , 4
A getter material 12 made of alloy powder is placed in a getter container 13.
An electrode part having a grid 2, a cathode 1, and a lead terminal 9 is formed using the getter 10, which is pressure-molded, and an anode substrate obtained in the same manner as in the first embodiment and a cover glass 7 are sealed with a frit glass 8. After a vacuum evacuation and sealing process, a getter layer 11 can be formed inside the tube.

Figure 3 shows Example 1a under constant anode and cathode voltages.
, 2b, the vertical axis is the relative brightness of the phosphor layer, and the horizontal axis is the operating time, and shows the relationship between them. The brightness after 100OH operation is 81% of the initial value in Conventional Example C, 95% in Example 1a, and 89% in Example 2b;
Compared to the above, the reduction in brightness of the fluorescent display tube of this example is clearly smaller.

Next, in FIG. 4, the horizontal axis represents the thickness of the B201 layer deposited on the Ni powder, and the vertical axis represents the brightness after 91,000 hours.

In this example, the deposited B 2 Os layers each have a thickness of 2.5
Although the thickness of the B2O3 layer deposited on the Ni powder is effectively 0.5 μm or more and 20 μm or less as shown in FIG.

〔Effect of the invention〕

As explained above, the present invention utilizes N to be used as a getter material.
By depositing the B201 layer on the surface of the i powder, it prevents oxidation of the Ni surface during the fluorescent display tube sealing process, prevents a decrease in the amount of Ba evaporation due to Ni oxidation, obtains a getter layer with excellent gas adsorption ability, and finally It is possible to obtain a fluorescent display tube with a long life.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a getter according to an embodiment of the present invention. FIG. 3 is a characteristic diagram showing the relationship between operating time and brightness of the embodiment of the present invention, and FIG.
FIG. 3 is a diagram showing the relationship between the brightness after the 00H operation and the thickness of the deposited B 20 s layer. 1... cathode, 2... grid, 3...
... Conductive layer, 4... Phosphor layer, 5. Old...
Glass substrate, 6... Spacer glass, 7...
...Cover glass, 8. Old... Frit glass, 9.
...Lead terminal, 1o, old...getter, 11...
...Getter layer, 12...Group getter substance, 13...
...Getta container. Agent Patent Attorney Susumu Uchihara 2 Gu Ruud Figure 1 Kesotar Container - Figure 2 Figure 3 Figure 4 Procedural Amendment Export)

Claims (1)

[Claims] A cathode that emits thermionic electrons in an envelope kept in a vacuum,
In a fluorescent display tube having an anode on which a phosphor layer that emits light by bombardment of thermoelectrons is formed, and a getter material called a thermal evaporation type, the getter material is made of at least an alloy of Ba and Al and Ni, and the Ni 0.5-20 on the surface
A fluorescent display tube characterized in that it is coated with B_2O_3 having a thickness of μm.