JP2747119B2 - Fluorescent display tube - Google Patents

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, and more particularly, to a fluorescent display tube of a type in which a divided grid and a glass substrate are fixed with a conductive material.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 2, a power supply wiring layer 2 (here, a grid power supply wiring is shown) is formed of Ag or Al on a glass substrate 1 as shown in FIG. , An insulating layer 3, a through-hole layer 4, a graphite electrode layer 5, and a phosphor layer 6 are sequentially applied and formed, and the supporting portion of the grid 8 is fixed on the through-hole layer 4 with a paste made of a conductive material. Thus, the conductive layer 17 was formed by baking, and the grid 8 was fixedly disposed at a position facing the phosphor layer 6.

A conductive material used for this type of fluorescent display tube is a liquid obtained by dissolving at least Ag powder and Pb-Si-Zn-B-based glass powder in a resin such as ethyl cellulose in a solvent such as butyl carbitol. It was in the form of a mixed paste, and after coating and firing, the conductive layer 17 containing at least Ag and glass was obtained. Table 1 shows the composition of this conventional conductive paste.

[0004]

[0005]

In this conventional fluorescent display tube, the conductive layer contains Ag and glass and has a coefficient of thermal expansion of 70 to 90 × 10 ⁻⁷ / ° C., whereas the grid 8 to be fixed is For example, when a 42% Ni-6% Cr-remaining Fe alloy is used, the thermal expansion coefficient is 100 × 10 ⁻⁷ min / ° C.
t500 ° C. or higher and about 50
At the contact interface between the conductive layer 17 baked at 0 ° C. and the grid 8, a minute crack was generated.

[0006] Due to the minute cracks, the conduction resistance between the conductive layer 17 and the grid 8 increases (for example, sometimes becomes 10 Ω or more), and the fixing strength between the conductive layer 17 and the grid 8 decreases (for example, tensile strength). (Strength: 5 g or less), the grid 8 peels off even with a slight impact (one generated during transportation during the fluorescent display tube manufacturing process, etc.), and the loss with respect to the applied voltage is large. There has been a problem that problems such as not being applied occur.

An object of the present invention is to provide a fluorescent display tube which does not increase the conduction resistance between the conductive layer and the grid and does not decrease the fixing strength.

[0008]

According to the present invention, a power supply wiring layer for an electrode layer and a power supply wiring layer for a grid are provided on at least a glass substrate, and an insulating layer, a through-hole layer, an electrode layer, and a phosphor layer are formed by coating. Further, a support portion of a grid divided by a conductive material is fixed to a part of the through-hole layer and the insulating layer formed on the grid power supply wiring layer, and a gap is provided at a position facing the phosphor layer. In a fluorescent display tube of the type in which a grid is provided, the conductive material contains at least one of Ag, glass and graphite, carbon, and a mixture of graphite and carbon. In addition, one kind of a mixture of graphite, carbon, and graphite and carbon has an Ag ratio of 1
0 to 100% by weight.

[0009]

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 an embodiment of the present invention.

First, Ag powder and Pb-Si-Zn-B-based glass powder (coefficient of thermal expansion: 80 × 10 ⁻⁷ / ° C.) graphite powder were prepared, and a mixture having a ratio shown in Table 2 was prepared.

[0012]

Next, a solution prepared by dissolving ethyl cellulose in a mixed solution of butyl carbitol acetate and terpineol was prepared and kneaded with the mixture shown in Table 2 to obtain a conductive paste.

Using these pastes, as shown in FIG. 1, the through hole layer 4 of the glass substrate 1 of the fluorescent display tube and the grid 8 are fixed (here, the conductive paste is applied by screen printing). After firing, the conductive resistance between the conductive layer 7 and the grid 8 and the adhesion strength by a tensile test were measured.

As a result, the results shown in Table 3 were obtained.
The addition of 5 to 50% by weight of graphite powder drastically improved the conduction resistance and the fixing strength.

[0016]

This effect can be obtained by changing the addition ratio of the graphite powder to other metal materials (for example, SU).
S430: thermal expansion coefficient 113 × 10 ⁻⁷ / ° C at 500
C.) can be obtained even when the grid 8 is used. When the addition ratio is less than 10 wt%, the effect of suppressing cracks is poor, and when it is 100 wt% or more, the tensile strength is reduced due to the deterioration of the strength of the conductive layer 7 itself. Therefore, the addition ratio of the graphite powder is 10 to 100 wt% of the Ag powder ratio.
% Is desirable.

In this embodiment, the addition of only graphite powder has been described, but the same effect can be obtained with carbon powder or a mixture of graphite powder and carbon powder.

When the graphite powder and the carbon powder to be used are fired in an oxidizing atmosphere, it is needless to say that those having an oxidation start temperature higher than the firing temperature must be used.

[0020]

As described above, according to the present invention, a grid is fixed on a through-hole layer with a conductive paste containing at least graphite and / or carbon in a conductive material made of Ag and glass, and fired. ,
The minute cracks due to the difference in the coefficient of thermal expansion generated at the contact interface between the conductive layer and the grid are suppressed, and the conduction resistance is reduced to 1/10.
As described below, it is possible to provide a fluorescent display tube in which the fixing strength can be improved by 10 times or more, and the display state and the reliability are greatly improved.

The above effect is remarkably exhibited when the content of graphite and / or carbon is in the range of 10 to 100% by weight of Ag.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of an example of a conventional fluorescent display tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Power supply wiring layer 3 Insulating layer 4 Through hole layer 5 Graphite electrode layer 6 Phosphor layer 7, 17 Conductive layer 8 Grid 9 Filament 10 Cover glass

Claims (1)

(57) [Claims] 1. A power supply for an electrode layer on at least a glass substrate.
Provide a wiring layer and a power supply wiring layer for the grid, and
-Hole layer, electrode layer, phosphor layer
The through hole formed on the power supply wiring layer for the grid;
Grid divided into layers and a part of the insulating layer by a conductive material
Of the phosphor layer, and the support portion is fixed at a position facing the phosphor layer.
Fluorescent display tubes with grids spaced apart
Wherein the conductive material is at least Ag, glass, and a graph.
A mixture of graphite, carbon, graphite and carbon
The graphite, and carbon.
One of a mixture of graphite and carbon
The content of one kind is 10% by weight to 10% by weight of Ag.
A fluorescent display tube having a range of 0% by weight .