JPH06318437A - Fluorescent display tube - Google Patents

Abstract

PURPOSE:To prevent shortcircuit caused by bleeding of conductive components in application and formation of a phosphor layer and a segment electrode by graphite, and improve production yield. CONSTITUTION:A third-layer insulation layer 43 having its height higher than the surface of a segment electrode (Gr) 5 by 10mum or less is additionally formed in a range which conventionally is a gap to the segment electrode (Gr) 5 formed by adjacent graphite through a conductive layer 7 on the segment electrode (Al or Ag) 3 of al or Ag. Electric shortcircuit caused by bleeding generated at the time of application and formation of a phosphor layer 6 and the segment electrode (Gr) can thus be prevented.

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 having a small gap between segments.

[0002]

2. Description of the Related Art A conventional fluorescent display tube is shown in FIG.
As shown in (b), a power supply wiring (Al or Ag) 2 and a segment electrode (Al or Ag) 2 made of an Al sputtered film or Ag are formed on the insulating substrate 1 made of a glass substrate by a photolithography method (in the case of Al. ) Or a thick film printing method (in the case of Ag). Next, a first insulating layer 41 and a second insulating layer 42 having an opening having the same area as or smaller than the segment electrode (Al or Ag) 3 are sequentially formed by coating.

Next, the conductive layer 7 is filled in the openings of the first and second insulating layers 41 and 42, and the segment electrode (Al or Ag) is formed on the second insulating layer 42 via the conductive layer 7. 3 segment electrode (G
r) Form 5. Furthermore, this segment electrode (Gr)
The anode substrate obtained by coating and forming the phosphor layer 6 on 5 was used.

In this conventional anode substrate, the area of the gap between the adjacent segment electrodes (Gr) 5 is the segment electrode (Gr).
Since the groove has a thickness of 20 μm or more corresponding to the thickness of r), the conductive component exuded at the time of applying the graphite or the fluorescent material is accumulated and the structure is likely to cause a short circuit.

[0005]

In this conventional fluorescent display tube, as shown in FIGS. 2A and 2B, the phosphor layer 6 is formed by coating on the segment electrode (Gr) 5.
When the segment electrodes (Gr) 5 are applied (generally screen printing), bleeding of a conductive component occurs between the adjacent segment electrodes (Gr) 5 and accumulates in the grooves to present an electrical short state, or a phosphor layer. There is a problem in that the same inconvenience occurs when applying 6 (generally screen printing).

This disadvantage is caused by the segment electrode (Gr) 5
The smaller the gap between them is, the higher the probability of occurrence is, and the limit of printing without short-circuiting in the conventional structure is that the gap between the segment electrodes (Gr) 5 is 0.22 mm and the phosphor interlayer gap is 0.34 mm. .

The object of the present invention is to segment electrode (Gr).
Another object of the present invention is to provide a fluorescent display tube having a high yield without causing a short circuit defect due to the occurrence of bleeding when the phosphor layer is applied.

[0008]

SUMMARY OF THE INVENTION The present invention comprises an insulating substrate,
A segment electrode and a power supply wiring made of Al or Ag formed on the insulating substrate, a first insulation layer and a second insulation layer which cover the power supply wiring and have an opening on the segment electrode, and a second insulation layer. In a fluorescent display tube having a segment electrode made of graphite connected to the segment electrode through a conductive layer formed on a layer and filled in the opening, and a phosphor layer formed on the segment electrode,
A third insulating layer is provided in a region serving as a gap between the segments made of adjacent graphite, and the height of the surface of the third insulating layer is suppressed within 10 μm from the height of the graphite made to the surface of the segment electrode. It has a raised structure.

[0009]

Embodiments of the present invention will now be described with reference to the drawings.

FIGS. 1 (a) and 1 (b) are a fragmentary sectional view of an embodiment of the present invention and a partially enlarged plan view of a segment electrode thereof. As shown in FIGS. 1A and 1B, first, on an insulating substrate 1 made of a glass substrate, a sputtered film of Al or a power supply wiring (Al or Ag) 2 made of Ag and a segment electrode (Al or Ag) 3 are formed. Are formed by a photolithography method or a thick film printing method. Next, a first insulating layer 41 and a second insulating layer 42 having an opening of the same area as or smaller than the segment electrode (Al or Ag) 3 are sequentially formed on the segment electrode (Al or Ag) 3 by coating. Then, the opening is filled with a conductive layer. Next, adjacent segment electrodes (Gr)
After forming the third insulating layer 43 in the area to be the gap of 5,
A segment electrode (G) that is coated with graphite to reduce the height of the surface of the third insulating layer 43 to within 10 μm
r) 5 is formed, and a phosphor is applied thereon by screen printing to form a phosphor layer 6 to obtain an anode substrate. By suppressing the height difference of the third insulating layer 43 within 10 μm, bleeding of the phosphor during screen printing can be prevented, and the phosphor layer 6 having a clear contour can be obtained.

Next, a filament for emitting thermoelectrons, a grid for accelerating and controlling thermoelectrons, etc. are arranged on the anode substrate, sealed with a cover glass, and then subjected to a predetermined manufacturing process such as exhaust gas exhaustion. Obtain a fluorescent display tube.

[0012]

As described above, according to the present invention, the adjacent segment electrodes (G
By providing a third insulating layer, which is kept within 10 μm and is higher than the surface of the segment electrode (Gr), in the region which becomes the gap of r), the bleeding generated during the coating formation of the segment electrode (Gr) and the phosphor layer is prevented. Therefore, there is an effect that it is possible to prevent shot defects and increase the manufacturing yield of the fluorescent display tube.

Due to this effect, for example, the cap between the phosphor layers is 0.25 (mm), and the gap between the segment electrodes (Gr) made of graphite is 0.22 (mm).
The fluorescent display tube can be manufactured without any problem in terms of yield.

[Brief description of drawings]

1A and 1B are a fragmentary cross-sectional view of an embodiment of the present invention and a partially enlarged plan view of a segment electrode thereof.

2A and 2B are a fragmentary cross-sectional view of an example of a conventional fluorescent display tube and a partially enlarged plan view of a segment electrode thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Power supply wiring (Al or Ag) 3 Segment electrode (Al or Ag) 5 Segment electrode (Gr) 6 Phosphor layer 7 Conductive layer 41 1st insulating layer 42 2nd insulating layer 43 3rd insulating layer

Claims (1)

[Claims] 1. An insulating substrate, a segment electrode made of Al or Ag formed on the insulating substrate and a power supply wiring, and a first layer insulation and a second layer which cover the power supply wiring and have an opening on the segment electrode. An insulating layer, a segment electrode made of graphite which is formed on the second insulating layer and is connected to the segment electrode through a conductive layer filled in the opening, and a phosphor layer formed on the segment electrode. In the fluorescent display tube having the third insulating layer, a third insulating layer is provided in a region which is a gap between the adjacent segments of graphite, and the height of the surface of the third insulating layer is higher than that of the segment electrode of graphite. Than 10μ
A fluorescent display tube having a structure in which the height is suppressed within m.