JPH0640472B2 - Method for manufacturing substrate for fluorescent display tube - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of manufacturing a substrate used for a fluorescent display tube, and more particularly to a method of manufacturing a fluorescent display tube in which an insulating layer is formed by an exposure method. .

[Conventional technology]

Conventionally, when manufacturing a substrate for a fluorescent display tube, a wiring pattern 2 such as an A thin film is formed on a glass substrate 1 serving as an insulating substrate (see the same figure), as shown in the schematic process thereof.
(a)) Next, the screen printing method 10 is used to apply an insulating paste 9 to predetermined positions to form a paste layer 9 (FIGS. 2B and 2C). At this time, the paste layer 9 covers substantially the entire surface of the glass substrate 1 including the wiring pattern 2, and a part 2a of the wiring pattern 2 and an anode pad (segment electrode) on which a fluorescent screen described later is to be formed. Are selectively formed, leaving a through hole 6 for connecting.

Next, the paste layer 9 thus formed is 560
It is fired at a high temperature of about 0 ° C., melted and fixed on the glass substrate 1 to form the insulating layer 9a (FIG. 2 (d)). Then, the anode pad 7 is formed on the insulating layer 9a through the through hole 6.
Is formed as a conductor layer, and the phosphor layer 8 is deposited on the conductor layer to form a phosphor screen ((e) in the same figure), whereby the substrate manufacturing process is completed. In FIG. 2, 11 is a screen mesh and 12 is a squeegee.

[Problems to be solved by the invention]

However, in such a conventional method, when the wiring pattern 2 is rough, there is no problem, but as the wiring pattern 2 becomes higher in density and higher in accuracy, the insulating layer 9a is properly printed and formed at a predetermined position as designed. If it is difficult to print at the correct position, the through hole 6
On the adjacent wiring pattern, resulting in contact. This is often because the screen mesh 11 used for screen printing gradually expands during use, and the position of the through hole 6 is displaced. Therefore, in the past, the screen mesh 11 was frequently replaced to take measures against the elongation of the screen mesh.
In this case, positioning work is required every time the screen mesh is replaced, which greatly deteriorates workability. Similar problems may occur due to variations in the pattern accuracy of the screen mesh.

As described above, the conventional method has a big problem that the yield is lowered due to the displacement of the through holes.

The present invention has been made in view of the above points, and provides a method of manufacturing a substrate for a fluorescent display tube that solves the above-mentioned conventional problems by using a photosensitive insulating paste that can be patterned in a photolithographic process. Is.

[Means for solving problems]

The method for manufacturing a substrate for a fluorescent display of the present invention comprises a step of forming a wiring pattern on the surface of an insulating substrate by a photo-etching method, and a paste layer formed by mixing a low melting point glass powder and a photosensitive liquid on the surface of the substrate. A process of forming by thick film printing, a process of exposing and developing the paste layer through a photomask on which a through hole pattern is formed, and a process of baking a substrate to thermally decompose the photosensitive liquid substance of the paste layer and to reduce it. It is characterized by comprising a step of melting and fixing the melting point glass powder and a step of forming an anode pad and a phosphor layer.

[Action]

In the present invention, since an insulating layer is formed by using a photosensitive insulating paste formed by mixing a low-melting glass powder and a photosensitive liquid, the insulating layer can be patterned by exposure, so that an insulating film faithful to the photomask can be obtained. Layers can be patterned.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to FIG.

1 (a) to 1 (e) are basic process sectional views showing an embodiment of a fluorescent display tube substrate according to the present invention, in which the same reference numerals as those in FIG. 2 designate the same or corresponding parts. ing.
First, the wiring pattern 2 is formed on the glass substrate 1 (see FIG.
(a)) Next, a photosensitive insulating paste 3 obtained by mixing a fritted glass as a low melting point glass powder and a photosensitive liquid material.
Is applied to the entire surface of the glass substrate 1 by a printing method or another method ((b) of the same figure). Then this paste layer 3
After drying, the exposure light 4 from the light source is exposed through a photomask 5 having a predetermined pattern (see FIG.
(c)) When the paste layer 3 is negative-type photosensitive, the exposed portion becomes insoluble in the developing solution, and the unexposed portion dissolves in the developing solution, forming a through hole 6 as shown in FIG. 1 (d). To be done. When the paste layer 3 is positive-type photosensitive, the exposed part is dissolved in the developer and the unexposed part remains, contrary to the negative type, and the through hole 6 can be similarly formed.

Next, after the paste layer 3 containing the fritted glass in which the through holes 6 have been formed by the exposure method as described above is baked and melted and fixed to form the insulating layer 3a (FIG. 2 (d)), the insulating layer 3a is formed on the insulating layer 3a. By forming the anode pad 7 and the phosphor layer 8 through the through holes 6, the fluorescent display tube substrate is manufactured.

In the substrate for a fluorescent display tube manufactured in this manner, the insulating layer 3a can be formed in a pattern that is faithful to the photomask 5, and the conventional displacement of the through hole is completely eliminated.

Next, embodiments of the present invention will be specifically described. First, deposit a thin film of 1.5 μm on the glass substrate by the sputtering method.
A thick film is formed, and this is patterned by a photo etching method to form a predetermined A wiring pattern. The A wiring pattern has a line width of 30 μm and a pitch of 60 μm, and the portion where the phosphor screen is to be formed has a pad shape of 200 × 250 μm. Next, a negative photosensitive insulating paste, which is a mixture of inorganic fritted glass and a photosensitive liquid material, is formed on the A wiring pattern by screen printing on the entire surface of the substrate by 10 μm.
It is formed by printing to a thickness, dried, and exposed using a predetermined photomask. The exposure amount of the ultra-high pressure mercury lamp during this exposure is 30
It is about 50 mJ / cm ² . Then, a spray phenomenon is performed at room temperature using 1-1-trichloroethane, and the unexposed portion of the paste layer is dissolved and a through hole is formed in that portion. Then, by firing in air at 560 ° C. for 30 minutes, the paste layer forming portion is melted and fixed, and the formation of the insulating layer having a through hole is completed. After that,
An anode pad and a phosphor layer were respectively formed to prepare a substrate for a fluorescent display tube.

Therefore, in manufacturing such a substrate, when the pattern shape was measured after the insulating layer was formed, a through hole almost faithful to the photomask dimension was obtained, and
Insulation layer pattern can be formed in the range of about μm,
Practically good. Further, when the insulating layer is formed by using the photosensitive insulating paste containing the fritted glass as in the above-mentioned example, compared with the one using the photosensitive insulating paste containing no fritted glass component (hereinafter referred to as an organic paste), The following problems do not occur, which is advantageous in manufacturing a fluorescent display tube. That is, none of the organic pastes can endure the heat process of the fluorescent display tube in reality, and the heat resistance of an actual heat-resistant organic paste, for example, a polyimide resin, does not reach about 450 ° C. and cannot be used. Even if a high heat resistant organic paste is produced, it is very expensive and a material (polyimide type) is used, which makes it difficult to use for a fluorescent display tube. Further, in the fluorescent display tube, the insulating layer near the fluorescent screen is easily impacted by electrons (in short, electrons are slightly hit), so that the bond of the organic paste layer is easily broken and decomposed, which serves as a gas emission source. This is because the organic paste layer has a weaker binding force than the inorganic frit.

〔The invention's effect〕

As described above, according to the method for manufacturing a fluorescent display tube substrate of the present invention, since the insulating film is formed using the photosensitive insulating paste containing the fritted glass, the predetermined film thickness required to obtain a high withstand voltage. Easy-to-form thick-film printing can be used to form the insulating layer, and its positional accuracy and pattern shape can be formed faithfully to the photomask, eliminating the conventional through-hole displacement and significantly increasing yield. There is an effect that can be improved.

[Brief description of drawings]

1 (a) to 1 (e) are basic process cross-sectional views showing one embodiment of a substrate for a fluorescent display tube according to the present invention, and FIGS. 2 (a) to (e) are conventional substrate for a fluorescent display tube. It is process sectional drawing which shows an example. 1 ... glass substrate, 2 ... wiring pattern, 3 ... photosensitive insulating paste containing fritted glass, 3a ... insulating layer,
4 ... light, 5 ... photo mask, 6 ... through hole,
7 ... Anode pad, 8 ... Phosphor layer.

Claims (1)

[Claims] 1. A step of forming a wiring pattern on the surface of an insulating substrate by a photoetching method, and a paste layer formed by mixing a low melting point glass powder and a photosensitive liquid material on the surface of the substrate by thick film printing. A step of exposing and developing the paste layer through a photomask having a through-hole pattern formed therein, baking the substrate to thermally decompose the photosensitive liquid substance in the paste layer, and melt and fix the low melting point glass powder. A method of manufacturing a substrate for a fluorescent display tube, which comprises the steps of: forming an anode pad and a phosphor layer.