JPS6290838A - Base plate for fluorescent display tube - Google Patents

Abstract

PURPOSE:To prevent positional shift of through-holes so as to greatly increase the yield of a base plate for a fluorescent display tube by using a paste prepared by making a low melting point glass powder and a photosensitive liquid to form an insulating layer with a pattern conforming with a photomask. CONSTITUTION:After a wiring pattern 2 is formed on a glass base plate 1, a photosensitive insulation plate layer 3 composed of a mixture of frit glass used as the low melting point glass powder and a photosensitive liquid is applied to the entire surface of the base plate 1. Next, after the layer 3 is dried, it is exposed to light 4 from a light source through a photomask 5 with a given pattern to form through-holes 6. The layer 3 containing the frit glass and having the through holes 6 is then sintered, fused and solidifed to form an insulating layer 3a. After that, an anodic pad 7 and a phosphor layer 8 are formed over the layer 3a through the holes 6, thereby forming a base plate for a fluorescent display tube.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a substrate used for a fluorescent display tube, and in particular, the present invention relates to a substrate used for a fluorescent display tube. ) The present invention relates to a substrate for a fluorescent display tube in which an insulating layer is formed by an exposure method using a photosensitive insulating paste containing the following.

[Conventional technology]

Conventionally, when manufacturing a substrate for a fluorescent display tube, the schematic process is shown in FIG. 2, in which a wiring pattern 2 such as an At thin film is formed on a glass substrate 1 serving as an insulating substrate.
[L)) Then, using the screen printing method 10, an insulating paste 9 is applied to a predetermined position to form a paste layer 9 (FIGS. 6(b) and (C)). At this time, the paste layer 9 is covers almost the entire surface of the glass substrate 1 including the wiring pattern 2, and also covers a part 21 of the wiring pattern 2.
It is selectively formed, leaving a through hole 6 for connecting L and an anode pad (segment electrode) on which a phosphor screen to be described later is to be formed.

Next, the paste layer 9 formed in this way has 560
It is fired at a high temperature of approximately .degree. C., and is melted and fixed onto the glass substrate 1 to form an insulating layer 9a (FIG. 1(d)).

Next, an anode pad I is formed as a conductor layer on this insulating layer 9a through the through hole 6, and a phosphor layer 8 is deposited thereon to form a phosphor screen (2) as shown in FIG.
)), the substrate fabrication process is completed.

In addition, in FIG. 2, 11 is a screen mesh, and 12 is a sugeige.

[Problem that the invention seeks to solve]

However, with such a conventional method, there was no problem when the wiring pattern 2 was rough, but as the wiring pattern 2 becomes denser and more precise, it becomes difficult to print and form the insulating layer 9a at a predetermined position correctly as designed. It is becoming difficult to
If the through hole 6 cannot be printed in the correct position, the through hole 6 will overlap and come into contact with the adjacent wiring pattern. This is often caused by the fact that the screen mesh 11 used for screen printing gradually stretches during use, causing the through holes 6 to be misaligned.

As described above, in the conventional devices, a decrease in yield due to misalignment of the through holes was a major problem.

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

[Means for solving problems]

In the fluorescent display tube substrate of the present invention, a wiring pattern is formed on the surface of an insulating substrate, and then an insulating layer is formed on the wiring pattern by leaving a through hole for connecting the wiring pattern and a conductor layer. In the fluorescent display tube substrate in which the conductor layer is formed on the insulating layer through the through hole, the insulating layer is formed of a paste made of a mixture of low melting point glass powder and a photosensitive liquid. It is characterized by

[Effect]

In the present invention, by forming an insulating layer using a photosensitive insulating paste made by mixing a low melting point glass powder and a photosensitive liquid, this insulating layer can be patterned by exposure to light, so it can be used as a photomask. Accurate insulating layer pattern formation is possible.

〔Example〕

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

1(-) 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, in which the same reference numerals as in FIG. 2 indicate the same or corresponding parts. ing. First, a wiring pattern 2 is formed on a glass substrate 1, and then a photosensitive insulating paste 3 made by mixing frit glass as a low melting point glass powder and a photosensitive liquid is applied using a printing method or The coating is applied to the entire surface of the glass substrate 1 by another method (FIG. 2(b)). Next, after drying this paste layer 3, it is exposed to irradiation light 4 from a light source through a photomask 5 having a predetermined pattern ((C) in the same figure). The unexposed part becomes resistant to the developer, and the unexposed part dissolves in the developer, forming a through hole 6 as shown in Figure 1(d).
is formed. However, if the paste layer 3 is positive type photosensitive, the exposed part will dissolve in the developer, contrary to the negative type.
The unexposed portion will remain, and a through hole 6 can be formed in the same way (-).

Next, in step A, the insulating layer 3a is formed by firing, melting, and fixing the paste layer 3 containing the frit glass in which the through holes 6 are formed by the exposure method (FIG. 1(d)). By forming an anode pad T and a phosphor layer 8 thereon through the through hole 6, a substrate for a fluorescent display tube is manufactured.

In the fluorescent display tube substrate manufactured in this way, it is possible to form a pattern of the insulating layer 3 & that is faithful to the photomask 5, and there is no misalignment of the through holes as in the conventional case.

Next, embodiments of the present invention will be specifically described.

If an At thin film is formed to a thickness of 1.5 μm on a glass substrate by sputtering, this is patterned by photoetching to form a predetermined At wiring pattern.

The wiring pattern for this person has a line width of 30 μm and a pitch of 60 Am.
The area where the phosphor screen was to be formed had a pad shape of 200 x 2501 zm. Next, on this At wiring pattern,
A negative photosensitive insulating paste made by mixing an inorganic frit glass and a photosensitive liquid is printed on the entire surface of the substrate to a thickness of about 10 μm using the 6 screen printing method, and after drying, it is exposed to light using a predetermined photomask. The exposure amount of the ultra-high pressure mercury lamp during this exposure is about 30 to 50 mJ/house. Next 1-1
-1? When spray development is performed using dichloroethane at room temperature, the unexposed portions of the paste layer are dissolved and through holes are formed in those portions.

Next, when baking is performed 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 through holes is completed. Thereafter, an anode pad and a phosphor layer were formed, respectively, to produce a substrate for a fluorescent display tube.

Therefore, when manufacturing such a substrate, we measured the pattern shape after forming the insulating layer, and found that through holes were obtained that were almost faithful to the photomask dimensions, and were within ±10
It became possible to form a pattern of the insulating layer within a range of about /Am, which was good for practical use.

In addition, when an insulating layer is formed using a photosensitive insulating paste containing frit glass as in the above example, compared to one using a photosensitive insulating paste (hereinafter referred to as organic paste) that does not contain frit glass component Kanakura. Therefore, there is no problem such as the first-order problem, which is advantageous in manufacturing a fluorescent display tube. In other words, there are no organic pastes that can withstand the thermal process of fluorescent display tubes, and there are currently existing heat-resistant organic pastes.
For example, polyimide resin has a heat resistance of only about 450° C., making it unusable. Even if a highly heat-resistant organic paste were created, it would be difficult to use in fluorescent display tubes because it would require extremely expensive materials (polyimide-based). Further, in a fluorescent display tube, the insulating layer near the phosphor screen is easily bombarded by electrons (in short, it is slightly hit by electrons), and as a result, the bonds in the organic paste layer are easily broken and decomposed, which becomes a source of gas emissions. This is due to the fact that the organic paste layer has a weaker bonding force than the inorganic frit.

〔Effect of the invention〕

As explained above, according to the substrate for a fluorescent display tube according to the present invention, by forming an insulating film using a photosensitive insulating paste containing frit glass, it is possible to form an insulating layer pattern faithful to a photomask. , there is no misalignment of through holes as in the conventional method, and the yield can be significantly increased.

[Brief explanation of drawings]

1(-) to 1(-) are basic process cross-sectional views showing one embodiment of a substrate for a fluorescent display tube according to the present invention, and FIG. 2(a>
1 to (-) are process cross-sectional views showing an example of a conventional fluorescent display tube substrate. 1...Glass substrate, 2...Wiring pattern, 3...
・Ning・Photosensitive insulation paste containing frit glass, 3a
...Insulating layer, 4...Light, 56@-Photomask, 6...Through hole, γ...Anode pad,
8...phosphor layer.

Claims (1)

[Claims] A wiring pattern is formed on the surface of an insulating substrate, and then an insulating layer is formed by leaving a through hole on this wiring pattern to connect the wiring pattern and the conductor layer, and the through hole is formed on this insulating layer. 1. A substrate for a fluorescent display tube, wherein the conductor layer is formed through a substrate for a fluorescent display tube, characterized in that the insulating layer is formed from a paste made by mixing a low-melting point glass powder and a photosensitive liquid.