JPS62110229A - Fluorescent screen forming method for fluorescent character display tube - Google Patents

Abstract

PURPOSE:To make a phosphor formable on a positive electrode in high density and high accuracy, by putting a substrate, being set in an electrolyte containing the phosphor and forming fluorescent screen on a surface of the positive electrode by means of an electrophoretic process, into a high temperature oven, and removing a resist. CONSTITUTION:After a photo-resist agent 20 is applied onto a substrate 1 where a thick film insulating layer 6 is formed, a groove of opening width (h) corresponding to a sub-scanning direction size in which a phosphor 4 is to be formed is removed by means of a photo-etching process. The substrate 1 covered with the phot-resist agent 20 except the opening width (h) is put into an electrolyte containing the phosphor, while the specified electric filed is impressed on a positive electrode 2 and its counter electrode, and the phosphor 4 is stuck to an exposed anode part by means of a electrophoretic process. Next, when the substrate 1 is put into a high temperature oven and burned, the resist film 20 is removed by evaporation. With this constitution, the phosphor 4 is accurately formed in a dotlike form.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a method for forming a fluorescent surface of a fluorescent display tube, and more specifically, it is applicable to light sources for various recording devices such as optical printers, digital copying machines, facsimile machines, and word processors. The present invention relates to a method for forming a fluorescent surface of a vine fluorescent display tube.

(Prior art) A large number of minute strip-shaped anode electrodes are arranged along the longitudinal direction of the substrate at minute intervals on a long substrate, and a phosphor surface is formed on the surface of each anode electrode. In a method for forming a fluorescent surface of a fluorescent display tube, a thick film printing method has conventionally been adopted as a means for forming a fluorescent material on a positive 11 fft tl for displaying characters.

However, with this method, it is difficult to minutely control the size of the phosphor, and there is a problem that it is difficult to obtain the desired size with high precision.

Also, other than the character Fumiko, it can be used as a means for forming a phosphor on an anode electrode with even higher precision.

A so-called photoetching method is employed in which a photoresist is coated on a phosphor, and the phosphor is shaped by exposing and developing the photoresist. However, this first
When a phosphor surface is formed by an etching method, the photoresist and the phosphor material or the cursed image and the phosphor material are mixed.
There is a problem in that the luminescent properties of the phosphor deteriorate.

(Objective) Accordingly, one object of the present invention is to provide a method for forming a fluorescent surface of a fluorescent display tube, which allows the formation of phosphors in positive +l1 AW & extremely high density and with high precision without deteriorating the light emitting characteristics. The goal is to offer the following.

(Structure) In order to achieve the above object, the present invention provides a method for forming a fluorescent surface of a fluorescent display tube after forming an anode electrode on a substrate.
A thick insulating layer is formed on these, a resist film is made, and a region for attaching the phosphor 14 is secured on the surface of the negative and anode electrodes by photoetching, and then the substrate is placed in an electrolytic solution containing a phosphor. , a fluorescent surface is formed on the positive polar surface by electrophoresis.

This method is characterized in that the substrate is placed in a high-temperature furnace and the resist is removed.

Hereinafter, a detailed explanation will be given based on one embodiment of the present invention.

In FIG. 2, which shows a cross section of a fluorescent display tube according to the present invention, reference numeral 1 designates a substrate made of glass, for example, and is constructed as an elongated material in the direction passing through the page (main scanning direction).

A large number of anode electrodes 2 are arranged on this substrate 1 in the main scanning direction (horizontal direction in FIG. 3). Each anode electrode 2 is formed of a vacuum-deposited aluminum film, and lead terminals are alternately drawn out in opposite directions.

Reference numeral 4 indicates a phosphor formed on the anode electrode, the surface of which is a phosphorescent surface, and in this embodiment, ZnO or Zn is deposited on the anode by electrophoresis.

Reference numeral 6 indicates a thick film insulating layer, which is formed of glass material on the substrate l by thick film printing. A control electrode 7 is provided on the thick film insulating layer 6, in which only the upper part of the phosphor dot has a slit-like opening, and the rest has a mesh-like shape, for example, a hexagonal mesh as shown in FIG. Above the control electrode 7, a wire-shaped cathode filament 1 is stretched.

The above-mentioned parts are covered with a face glass 9, and the inside is kept in a vacuum state. Note that a transparent NESA electrode IO for antistatic purposes is formed on the back side of the upper surface of the face glass 9.

FIG. 3 shows a plan view of such a fluorescent display tube, and reference numeral II designates a fixing member for the 11 triode filament.

Reference numeral 12 indicates a spring plate for tensioning the Kageda filament.

In such a fluorescent display tube, the anode ff! The procedure for forming a fluorescent surface by the fluorescent material 4 on the pole 2 is as follows.

(1) Formation of anode electrode and thick insulating layer (see Figure 5)
.

First, aluminum was vacuum-deposited on the base +1i1 to form a -i aluminum film, and by photoetching,
<Create tooth-shaped positive +4i it pole 2. and,
A thick film insulating layer 6 is formed thereon using a glass plate by a thick film printing method. As shown in FIG. 5, this thick film insulating layer 6 is formed except for the groove-shaped opening 11 width portion including the phosphor formation region.

(2) Formation of phosphor formation area (see Figures 1 and 5)
.

After coating the photoresist agent 20 on the base @1 on which the thick film insulating layer 6 is formed, a groove with an opening width corresponding to the size in the sub-scanning direction in which the phosphor 4 is to be formed is removed by photoetching. do. At this time, it is assumed that each opening width satisfies the relationship H>h. For example, if H=200 μm, then h=50 μm. When using a fluorescent display tube in an optical printer, it is desirable for this size to be approximately the same size in both the main scanning direction (longitudinal direction) and the sub-scanning direction from the viewpoint of resolution, and dot density. 30
If it is 0 (dots/inch), the anode pitch in the main scanning direction is 87 μm, the anode electrode width is 5Q7+m, and the electrode spacing is 37
This comes from the fact that it is μm.

(3) Formation of phosphor (see Figures 4 and 5).

The substrate 1, which is thus covered with the photoresist agent 20 except for the opening width, is placed in an electrolytic solution containing a phosphor, and the anode? ! A predetermined electric field is applied to one electrode 2 and a counter electrode, and the phosphor 4 is electrophoresed.

It is attached to the exposed anode part (50 μm x 50 μm).

(4) Removal of resist agent Once the phosphor 4 has been attached, the first step is to remove the resist film 20 by placing the substrate 1 in a high-temperature oven (~50 mL).
0℃) and bake for about 1 hour.

Then, the resist v20 is evaporated and removed.

Through the above procedure, the phosphor 4 is formed into a dot shape, and each surface forms a phosphorescent surface.

In this example, in step (2), the resist film was etched into a slit shape with the width of the opening. Correspondingly positive + L [e.g. 5 on pole 2
Etching can also be performed with square openings of 0 μm x 50 μm. With this dimension, the exposed portion of the anode electrode corresponds to the size of the phosphor, so that the phosphor can be more easily attached by the electric method.

In any of the embodiments, unlike the prior art, the phosphor 4 is not directly exposed to resist agent, developer, etc.
Deterioration of the characteristics of the phosphor can be prevented.

In addition, since the size of the phosphor 4 is precisely controlled and formed by shaping the photoresist, there is little variation in the phosphor size (dot size), and therefore, when configured as a fluorescent display tube, there is no variation in the amount of light. You also get benefits with less. Furthermore, the formation of fluorophores of minute dot size is also possible, e.g.

Densities as high as 400 dots/inch can be achieved.

Once the resist agent is removed in this way, the thick film insulation N!
6 is provided with a control electrode 7 and a cathode filament 8, and a face glass 9 is fused and vacuum sealed to complete a fluorescent display tube.

(Effects) According to the present invention, the phosphor can be formed on the anode at high density and with high accuracy without deteriorating the light emission characteristics, which is advantageous.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a substrate in the process of forming a fluorescent surface according to the present invention, FIG. 2 is a sectional view of a fluorescent display tube, FIG. 3 is a plan view of the fluorescent display tube, and FIG. 4 is a diagram of a control electrode. The enlarged front view, FIG. 5, is a plan view corresponding to FIG. 1. ■...Substrate, 2...Anode electrode, 6...Thick film insulating layer, 20...Resist IvA. (1) "Luminescence" in line 300, line 3 of the specification was changed to "Luminescence procedure amendment document effective January 9, 1986.

Claims (1)

[Claims] A large number of minute strip-shaped anode electrodes are arranged at minute intervals on a long substrate along the longitudinal direction of the substrate, and a fluorescent surface is formed on the surface of each anode electrode. In the method for forming a fluorescent surface of a fluorescent display tube, an anode electrode is formed on a substrate, a thick insulating layer is formed on top of the anode electrode, a resist film is formed, and the surface of the anode electrode is formed by photo-etching. After securing the phosphor attachment area, the substrate on which the resist film is formed is placed in a phosphor-containing electrolytic solution, a phosphor surface is formed on the anode electrode surface by electrophoresis, and the substrate is placed in a high temperature furnace. 1. A method for forming a fluorescent surface of a fluorescent display tube, characterized in that the fluorescent display tube is manufactured through a step of placing the resist in the tube and removing the resist.