JPH0892551A - Fluorescent display tube - Google Patents

Abstract

PURPOSE: To obtain a fluorescent display tube capable of improving luminescent characteristics of a fluorescent substance layer and providing luminescence having uniform and high luminance, by mixing a fluorescent substance layer consisting essentially of a ZnCdS-based or a ZnS-based fluorescent substance with a specific amount of boron oxide. CONSTITUTION: This fluorescent display tube is obtained by providing an anode (e.g. a carbon layer, an aluminum layer or a transparent electrically-conductive layer not containing low-melting glass) 4' of an anode substrate 6 with a fluorescent substance layer 5' containing 0.001-10 pts.wt. of boron oxide based on a ZnCdS-based fluorescent substance (e.g. Zn0.30 Cd0.70 S:Ag+In2 O3 ) or ZnS (e.g. ZnS:Cu, Al+In2 O3 )-based fluorescent substance and irradiating the fluorescent substance layer 5' with low-velocity electrons to excite and emit light rays. The fluorescent substance layer 5', for example, is formed by making a mixture of the ZnCdS-based or ZnS-based fluorescent substance and a prescribed amount of boron oxide into a paste, printing it on the anode 4' and baking the mixture at about 500 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent display tube for displaying by utilizing light emission of a phosphor excited by a slow electron beam, and more particularly to a phosphor layer containing ZnCdS or ZnS phosphor as a main component. The present invention relates to a fluorescent display tube having improved light emitting characteristics.

[0002]

2. Description of the Related Art Conventional fluorescent display tubes of this type have a structure in which the light emitted from a phosphor layer 5 is observed through a transparent face glass 9 as shown in FIG. As shown, there is a structure in which the transparent anode substrate 6 is observed through.

In the structure shown in FIG. 3, a wiring layer 2 made of Ag having a predetermined pattern and an insulating layer 3 made of low melting point glass are formed on a glass substrate 1 made of, for example, soda lime glass by a screen printing method. An anode 4 having a predetermined pattern is formed on the surface of the insulating layer 3 through the through hole 3a so as to be electrically connected to the wiring layer 2 by screen printing of carbon paste and firing, and then ZnO: Zn (emission color) is formed on the anode 4. : Blue-green) and ZnC
A low-speed electron beam phosphor layer 5 such as dS: Ag + In ₂ O ₃ (emission color: various colors from blue to red can be obtained by changing the ratio of Zn and Cd) is deposited.

On the anode substrate 6 thus formed, the grid 7 and the cathode (W thin wires (Ba, Sr, C
a) O-coated filamentary oxide cathode) 8 is provided, and a vacuum container is formed by sealing with a transparent face glass 9 by a low melting point glass (not shown). Further, in this structured bulb, the inner surface of the face glass 9 is covered with a transparent conductive film 10 for the purpose of blocking an external electric field.

In the structure shown in FIG. 4, the wiring layer 2 and the transparent anode 4 are formed on the glass substrate 1 made of, for example, soda lime glass by photo-etching of Al or a transparent conductive film.
And the insulating layer 3 is formed by screen printing.
And the phosphor layer 5 are sequentially formed. After the grid 7 and the cathode 8 are provided, the face glass 9 is sealed and a vacuum container is formed. Further, in the tube having this structure, in order to prevent light emitted from the phosphor layer 5 from being reflected on the inner surface of the face glass 9, a rear electrode 11 made of a carbon layer having a low reflectance is provided instead of the transparent conductive film. Has been.

[0006]

However, in the fluorescent display tube having such a structure, for example, a ZnCdS-based phosphor (for example, ZnCdS: Ag + In) is used as the phosphor layer 5.
₂ O ₃ ) or ZnS-based phosphor (eg ZnS: Cu, A
When 1 + In ₂ O ₃ ) is used, its surface is oxidized and decomposed by the heat treatment in the manufacturing process of the fluorescent display tube, resulting in low brightness. In particular, this inconvenience is likely to occur when the anode 4 is formed of a carbon paste (for example, an aqueous carbon paste) that does not contain low melting point glass, Al or a transparent conductive film.

The reason why the carbon paste containing no low melting point glass is used for the anode 4 is that the use of the carbon paste containing low melting point glass causes a problem that the emission capability of the cathode is significantly lowered. In many carbon pastes that do not contain low-melting glass, water glass is used instead of low-melting glass to provide the adhesive force.

Therefore, the present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to provide a fluorescent display tube having excellent light emitting characteristics.

[0009]

In order to achieve such an object, the fluorescent display tube according to the present invention has a phosphor layer containing boron oxide.

[0010]

In the present invention, the phosphor layer containing boron oxide improves the emission characteristics of the phosphor layer.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. (Embodiment 1) FIG. 1 is a cross-sectional view of an essential part showing the structure of an embodiment of a fluorescent display tube according to the present invention, and the same parts as those in FIG. 3 described above are designated by the same reference numerals. In FIG. 1, a wiring layer 2 made of Ag paste and an insulating layer 3 having a low melting point glass as a main component are sequentially formed on a glass substrate 1 by a screen printing method, and then carbon (graphite) and a carbon having a vehicle as a main component are formed. The paste was used to form the anode 4 '. Next, Zn _0.30 Cd _0.70 S:
A paste obtained by adding boron oxide to Ag + In ₂ O ₃ (emission color: orange) was made into a paste, printed, and baked at about 500 ° C. to form a phosphor layer 5 ′.

In this case, the addition ratio of boron oxide was changed within the range of 0 to 20 parts by weight with respect to the phosphor. After that, the grid 7 and the cathode 8 were provided, and the face glass 9 was sealed and then exhausted. The results of examining the luminance of the phosphor layer 5'after aging are shown in Table 1 below.

[0013]

[Table 1]

As can be seen from Table 1, boron oxide is 0.001
In the range of 10 to 10 parts by weight, the brightness was improved and the improvement effect was recognized as compared with the conventional product (boron oxide: 0%).

(Embodiment 2) FIG. 2 is a cross-sectional view of an essential part showing the structure of a fluorescent display tube according to another embodiment of the present invention.
The same parts as those in FIG. 4 described above are designated by the same reference numerals. In FIG. 2, as in the case of FIG.
The wiring layer 2 and the translucent anode 4 were sequentially formed by a photoetching method for a thin film, and then the insulating layer 3 was formed by a screen printing method. Next, on this anode 4, ZnS: Cu,
A paste obtained by adding boron oxide to Al + In ₂ O ₃ (light emission color: green) was formed into a paste, printed, and baked at about 500 ° C. to form a phosphor layer 5 ″.

In this case, the addition ratio of boron oxide was changed within the range of 0 to 20 parts by weight with respect to the phosphor. After that, the grid 7 and the cathode 8 were provided, and the face glass 9 was sealed and then exhausted. The results of examining the emission luminance of the phosphor layer 5 ″ after aging are shown in Table 2 below.

[0017]

[Table 2]

As can be seen from Table 2, the content of boron oxide is 0.001.
In the range of 10 to 10 parts by weight, the brightness was improved and the improvement effect was recognized as compared with the conventional product (boron oxide: 0%).

The phosphor layer 5'in such a structure,
It is speculated that the 5 ″ brightness improvement may be due to the fact that the surface of the phosphor particles is coated with boron oxide, which has the effect of preventing the phosphor surface from being oxidized or decomposed in the heat step.

In the above embodiment, the anode 4'is made of carbon (graphite) as the anode material and the carbon paste containing the vehicle as the main component, or A
Although the case where the anode 4 is formed of a thin film has been described, the present invention is not limited to this, and similar effects can be obtained when water-based carbon or a transparent conductive thin film is used.

[0021]

As described above, according to the present invention,
By including boron oxide in the phosphor layer containing a ZnCdS-based or ZnS-based phosphor as a main component, the luminescent characteristics of the phosphor layer are improved, and an extremely excellent effect that uniform and high-luminance light emission is obtained is obtained. It is obtained and the practical effect is extremely large.

Further, by using a carbon layer, an aluminum layer or a transparent conductive film which does not contain low melting point glass as the anode, there is an extremely excellent effect that a cathode having excellent emission ability can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts showing a configuration according to an embodiment of a fluorescent display tube according to the present invention.

FIG. 2 is a sectional view of an essential part showing the configuration of another embodiment of the fluorescent display tube according to the present invention.

FIG. 3 is a cross-sectional view of an essential part showing the configuration of a conventional fluorescent display tube.

FIG. 4 is a cross-sectional view of an essential part showing the structure of a conventional fluorescent display tube.

[Explanation of symbols]

1 ... Glass substrate, 2 ... Wiring layer, 3 ... Insulating layer, 4, 4 '...
Anode, 5, 5 ', 5 "... Phosphor layer, 6 ... Anode substrate, 7 ...
Grid, 8 ... Cathode, 9 ... Face glass, 10 ...
Transparent conductive thin film, 11 ... Back electrode.

Claims (2)

[Claims] 1. ZnCd formed on an anode of an anode substrate
In a fluorescent display tube that irradiates a phosphor layer containing an S-based or ZnS-based phosphor as a main component with a low-speed electron beam to excite and emit light, the phosphor layer contains 0.001 to 1 of boron oxide with respect to the phosphor.
A fluorescent display tube characterized by containing 10 parts by weight. 2. The fluorescent display tube according to claim 1, wherein the anode comprises a carbon layer, an aluminum layer or a transparent conductive film which does not contain low melting point glass.