JPS58214252A - Production method of shadow mask - Google Patents

Abstract

PURPOSE:To form a thin photosensitive film uniform in thickness and with no coating unevenness by adding 0.001%-3% of a boundary surface active agent to a photosensitive liquid in a shadow mask used for a color CRT with high resolution. CONSTITUTION:A long belt-like pure ion soft steel plate prepared as a raw material for a shadow mask is cleaned then continuously coated with a photosensitive liquid composed of 1kg of refined casein, 10gr of ammonium dichromate, a boundary surface active agent, e.g., 2cc of ''Disform CD-432'' and 0.8 (1) of water at a coating speed of 3.0m/min. As to the added quantity of the boundary surface active agent, an excellent result is obtained at 0.001%-3.0%, but the wet characteristic of the photosensitive liquid is not improved and a photosensitive film with no coating unevenness can not be obtained at 0.001% or less, and the photosensitive film is destroyed during the etching process performed for 5min as an after-process at 3% or more.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for manufacturing a shadow mask, and particularly to a method for manufacturing a shadow mask used in a color cathode ray tube (hereinafter simply referred to as a high-resolution tube) having high resolution. .

[Technical background of the invention and its problems]

With the recent spread of computers, the demand for high-resolution tubes as information display devices for text and graphics is increasing.

In this high-resolution tube, the pitch of the electron passing holes drilled in the shadow mask button (hereinafter referred to as "hole pitch") and the hole diameter of the electron beam passing holes are both similar to that of a color picture tube commonly used for home use. It is extremely fine compared to the previous model and requires strict dimensional accuracy. That is, the hole pitch is 0.2 to Q, 3m, and the hole diameter is 0.08 to 0.
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As a condition for strictly controlling such dimensional accuracy, first of all, how to faithfully reproduce the dimensions of the original negative pattern on the shadow mask material, such as pure iron mild steel plate or amber plate, on which the photoresist film is applied. I'm suffering from a crab. The key to this faithful reproduction is the process up to the etching process in the shadow mask manufacturing process.

The main point is that when a photoresist is applied to the shadow mask material and a photoresist film is deposited through a dry film formation process, firstly, the photoresist film is formed to the extent that it can withstand the subsequent etching process. The second reason is that the photoresist film has a uniform thickness over the entire surface of the shadow mask material, and there is no uneven coating.

The reason for this first condition is that when the photoresist film is thick, when a thick plate negative pattern is exposed in close contact with the photoresist film, light beams wrap around within the photoresist film. Since the phenomenon is small υ, accurate exposure, that is, accurate etched areas can be obtained. Second, the manufacturing process of a shadow mask is after the photoresist film has been deposited, the exposure, development, draining, and drying steps are completed.
A burning process is performed to improve the etching resistance of the photocured photoresist film, but in each of these steps, the phenomenon in which casein, etc. in the photoresist film seeps into the etched area can be reduced by making the photoresist film thinner. .

However, in order to improve the adhesion of the photosensitive film, the surface roughness of the shadow mask material is R2: 0.5 to 2.0 μ.
Rmax" is within 401', and in order to obtain a photosensitive film without uneven coating by applying a photosensitive liquid to a shadow mask material with such surface roughness, a film thickness of approximately 5 to 8 microns is required. be.

This film thickness is not a problem for manufacturing general shadow masks.
Although a shadow mask of good quality can be obtained, shadow masks used in high-resolution tubes having the above-mentioned aperture pitch and diameter have the problem of poor cine performance due to the above-mentioned reasons.

[Purpose of the invention]

The present invention was devised in view of the above-mentioned problems, and it is possible to form a thin photoresist film with a uniform thickness and no uneven coating.As a result, a shadow mask of extremely high quality can be obtained. The purpose of the present invention is to provide a method for manufacturing a shadow mask that allows for the production of shadow masks.

[Summary of the invention]

That is, the present invention provides a method for manufacturing a shadow mask, which includes a step of applying a photosensitive liquid to a long strip of shadow mask material, and then continuously forming a photosensitive film of a predetermined thickness through a dry film forming process. It is characterized by adding o, ooi, to tertiary surfactants to the liquid.

[Embodiments of the invention]

Next, an embodiment of the shadow mask manufacturing method of the present invention will be described.

As a shadow mask material, the surface roughness of 0.131m thick and 460n width is R2: 0.5~2.0μ, Rmax:
Prepare a long belt-shaped pure iron mild steel plate of 4.0 or less, and after cleaning the pure iron mild steel plate, add purified casein 1xP, ammonium dichromate 1 (1), and as a surfactant, for example, Disform CD- 432 (manufactured by Nippon Oil & Fats, product name) 2 c
c, a photosensitive liquid consisting of 0.8 ml of water at a coating speed of 3.0 Vm.
When the photoresist film was applied continuously under the same conditions as before, and a photoresist film was formed through a dry film formation process, the film thickness was 3°5±0.
A 5 μm photoresist film could be coated evenly.

According to experiments, good results were obtained when the amount of surfactant added was between 0% and 0%, and when it was less than 0001%, the wetting characteristics of the photosensitive liquid were not improved and a photosensitive film without uneven coating was obtained. If it exceeds 3%, it will be carried out in the subsequent process.
Specific gravity 1. carried out after the 0'C 1 minute baking process.
460±0.010 ferric chloride solution at a liquid temperature of 65±1°C and a spray pressure of 1.0 to 2. The photoresist film was destroyed during the etching process carried out for 3 to 5 minutes in OKp.

In the above examples, Disform CD-
432 is used, but it is not limited to this, and it goes without saying that an amber plate may be used as the shadow mask material.

〔Effect of the invention〕

As described above, according to the method for manufacturing a shadow mask of the present invention, it is possible to form a photoresist film having a thin and uniform thickness that can withstand the etching process, and to form an etched portion having the same shape as the negative pattern on the original plate. Therefore, it is suitable not only for high-resolution tubes but also for producing shadow masks for commonly used color picture tubes, and its industrial value is extremely high.

Agent Patent Attorney Inoue - Male

Claims (1)

[Claims] A method for producing a shadow mask, which includes a step of applying a photosensitive liquid to a long strip-shaped shadow mask material and continuously forming a photosensitive film of a predetermined thickness through a dry film forming process, wherein the photosensitive liquid is coated with o. , oois to 3 surfactants are added thereto.