JPS5866236A - Forming method of phosphor screen - Google Patents

Abstract

PURPOSE:To form a fine phosphor screen by impregnating a positive type resist in the phosphor formed on an anode electrode and by employing a photolithography method exposing from the rear of a substrate using the anode electrode as a photo mask so as to remove the phosphor protruded from the anode electrode and to arrange the shape of the phosphor screen. CONSTITUTION:A positive type resist is spread on a substrate electrodeposited with a phosphor layer 3 by means of a spinner method, and pre-baking is performed for a predetermined time. As a result, the resist impregnates into the phosphor layer so that the phosphor layer 3 is stuck to the substrate by the resist. Next, exposure is performed from the rear of the substrate, and subsequently development, rinsing, and drying are performed, thereby the phosphor layer protruded from the periphery of the Al thin film 2 is dissolved and removed together with the resist, and only the phosphor 3 with the same shape as that of the Al thin film 2 is left behind. Furthermore, sintering is performed at 580 deg.C for some 30min to remove the unnecessary resist, thus an excellent phosphor screen with no protrusion of the phosphor can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a fluorescent surface in a fluorescent display tube, and particularly to a method for removing phosphor protruding from an anode electrode.

Conventionally, methods such as electrodeposition and printing have been used to form a fluorescent surface on the anode electrode in fluorescent display tubes, but as wiring patterns and pitch dimensions become finer, When a phosphor is deposited by a certain method, the extrusion 1 from the anode electrode has become non-negligible.

FIG. 1 shows this type of fluorescent surface. Figure (1) is a plan view, and Figure (1) is a cross-sectional view. In FIG. 1, the glass group [1
The phosphor 3 deposited on the At thin film 2 as an anode electrode formed on the surface of the phosphor 3 protrudes irregularly into the periphery of the At thin film 2. Now, for example, 50 μm pitch, 308
When a phosphor is electrodeposited on an m-wide At thin film pattern, the protrusion of the phosphor from the anode electrode is more than 20# on one side, and the width of the phosphor surface is 70J! 1, and the button comes into complete contact with the adjacent fluorescent surface.

The present invention was devised in view of the above-mentioned circumstances, and its purpose is to remove the phosphor protruding from the anode electrode, shape the phosphor surface, and form a fine phosphor surface. The purpose of the present invention is to provide a method for forming a fluorescent surface that enables the following.

In order to achieve such an object, the present invention uses a photophosphorography technique in which a phosphor formed on an anode electrode is impregnated with a positive resist, and the anode electrode is used as a photomask to emit light from the back surface of the substrate. Then, the fluorescent material protruding from the positive electrode is removed to obtain a fluorescent surface having the same shape as the positive electrode. Therefore, in this case, it is assumed that the fluorescent surface portion of the anode electrode is non-transparent and that the substrate is transparent. The present invention will be described in detail using Examples below.

FIG. 2 shows a fluorescent surface formed in accordance with one embodiment of the present invention. In the figure, (a) is a plan view, and (b) is a sectional view.

When forming such a fluorescent surface, first, the glass substrate 1 is
1 to 2 μm thick on the surface of
An At thin film 2 having a thickness of, for example, 20 to 50 μm in line width and 30 to 100 μm in pitch is formed into an anode pattern by photoetching. Next, 20 to 4
A 0 μm thick phosphor layer is deposited. At this time, the phosphor layer protrudes in an irregular shape by 20 to 40 μms from the periphery of the A28M2 underneath.

Next, a positive resist is applied to the substrate on which the phosphor layer has been electrodeposited using a spinner method, and pre-heated for a predetermined period of time.
Let's do a song. As a result, the print impregnates the phosphor layer, and the phosphor layer becomes affixed to the substrate by the resist.

Next, exposure is performed from the back side of the substrate, followed by development and
When dried after rinsing, the phosphor layer protruding from the periphery of the At thin film 2 is removed by co-dissolution with the resist, leaving only the phosphor 3 in the shape of the Aj thin film 2. . In this case, the resist deposited on the phosphor layer is
Although it is not exposed to light and therefore does not dissolve in the present solution, the boundary portion with the glass substrate 1 is exposed to light and dissolves in the present solution.
It peels off and is removed together with the resist in this area. Note that if exposure from the back side alone does not provide a sufficient amount of exposure to remove the resist in the upper layer, exposure from the front side of the substrate may also be performed to compensate for the lack of exposure. For exposure from the front side, a photomask having through holes corresponding to the At thin film 2 is used.

Next, baking is performed at 580° C. for about 30 minutes to remove unnecessary resist, thereby forming a good phosphor surface without oozing out the phosphor.

When forming a dot-shaped fluorescent surface, the dot portion of the anode electrode is formed of an opaque thin film made of At, for example, and
Other parts, for example, I. By forming the transparent thin film made of 203 or the like, it is possible to easily form a fluorescent surface having the same shape as the dot portion made of the upper opaque thin belly.

Next, the case of forming a fluorescent surface of a fluorescent display tube used as a light emitting element array for an optical printer capable of printing on plain paper will be described in more detail.

(Specific Example 1) As shown in Fig. 3, a transparent thin film with a thickness of 0.2 μm was formed on the entire surface of the glass substrate 1 by a vapor deposition method, after cutting it into a predetermined size and cleaning it. 2048 anode patterns each consisting of transparent thin film 4 having a line width of 50 μm and a pitch of 100 μm were formed by patterning.

Next, the part where the phosphor is to be formed, that is, the tip of each rectangular transparent screen J[4] is etched using a normal photoetching method to form a 1.5 μm thick At thin H2 film with dimensions of 50 #m x 50 μm.
was formed. Next, a phosphor layer was formed on this substrate by electrodeposition. The electrodeposition conditions were DC 15°V and application for 3 minutes, and as a result, zno:zn firefly particles could be formed with two parts thickly. Next, AZ1350 positive resist diluted by adding 1 part of thinner to 5 parts of the stock solution was applied at a rotational speed of 1.
, 200 rpm for 10 minutes, and then pre-baked at 70C for 10 minutes.

Next, from the back side of the substrate, an exposure intensity of 1.1ootaW/3 was applied.
! After 2 minutes of exposure with a mercury lamp, a special working solution (l
: 1 diluted solution) for 1 minute, rinsed with running water and dried. After drying, the substrate was placed in an electric furnace and heated at 580"C.
, the resist was removed by baking for 35 minutes, and the formation of the fluorescent surface was completed.

As a result of stabilizing the three phosphors formed in this manner using a microscope, their dimensions were on average 51/jm x 5011 m, and their shape was almost the same as that of the thin film 2, and was Irregular protrusion around 'x could not be observed at all.

Note that the line width was 15 μm using the same method as described above.

A fluorescent surface was also formed on an anode pattern with a pinch of 30 μm, but it was not possible to form a good fluorescent surface with high precision as described above.

(Specific Example 2) On a glass substrate cut to predetermined dimensions and cleaned, A of 1.5 mm thickness was formed by planar magnetron sputtering.
It was formed on the entire surface of t1FJIIk and then patterned to form 2048 rectangular anode patterns with a line width of 50 μm and a pitch of 100 μm. Next, a phosphor paste mixed with a binder is printed in a 100 μm wide band with a thickness of 25 μm so as to connect the tips of the strip-shaped anode patterns, and after drying, baking is performed at 560° C. for 35 minutes to bind the binder. was removed. Next, AZ1350 resist was coated on the substrate with the phosphor adhered to it in the same manner as described in Example 1, and exposed, exposed, rinsed, and
After drying, the unnecessary resist was baked to complete the formation of the fluorescent surface.

The average size of the phosphor thus formed was 52 μm.
X118 μm, and no irregular protrusion to the periphery of the anode pattern was observed.

As explained above, the original F! According to iJk, it is possible to completely eliminate the phosphor from the fine anode pattern and form a clear phosphor pattern. In order to use the anode pattern as a photomask, there is no need for a special photomask for forming a fluorescent surface, and
It also eliminates the need for a mask matching process, simplifies the process, and has various excellent effects such as higher economic efficiency.

[Brief explanation of the drawing]

FIGS. 1(a) and (b) are a plan view and a sectional view showing a fluorescent surface formed by a conventional method, and FIGS. 2(1) and (b) are a surface formed by an embodiment of the present invention. Plan view and cross-sectional view showing the optical surface, Figure 3 (1) and Cb)
FIG. 7 is a plan view and a cross-sectional view showing a fluorescent surface formed according to another embodiment of the present invention. 1 m*@@glass substrate, 2--e-azlJ[,3・
...fluorescent material, 4...transparent thin film.

Claims (1)

[Claims] A step of forming an electrode pattern on a transparent glass substrate in which a portion where a phosphor is to be formed is opaque, a step of depositing and forming a phosphor layer on this electrode pattern, and a step of forming a phosphor layer on the electrode pattern. After impregnating a positive type photoresist on the photoresist layer, a step of exposing the glass substrate from the back side, and a process of exposing the exposed area to positive! l! 7. A method for forming a phosphor surface, comprising the step of peeling off and removing the OtoV cyst and the phosphor layer.