JPS6196085A - Manufacture of shadow mask - Google Patents

Abstract

PURPOSE:To form a resistive film having uniform thickness and no pinholes, by coating a metal sheet for material with resistive agent in divided 2 times and drying it while carrying said sheet whose width direction is held vertically, at forming resistive film in manufacturing process of shadow mask for color picture tube. CONSTITUTION:In process for forming resistive film to Al killed steel strip sheet for shadow mask for color picture tube, said sheet is carried while holding the width direction vertically. At first, said sheet is degreased (B) with alkaline liquid, washed with pure water, etc. to wash away (C) degreasing liquid. Next, aqueous soln. of resistive agent is flow coated (D) by forked nozzle from upper end part of said steel sheet, and upper part from center part in sheet width of masking material is dried (E). Thence, the second time resistive agent is coated (F) by flow coating from the upper end part similarly, then whole surface is dried (G), and resistive film having uniform thickness in sheet width direction, with no pinholes and bubbles is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method of manufacturing a shadow mask for a color picture tube, and particularly relates to a resist film forming step.

[Technical background and problems of the invention]

Shadow masks for color picture tubes are generally made by a method called photoetching (two steps). This method can be roughly divided into: (1) forming a strip-shaped metal plate screen (a process of forming a resist film with the desired thickness for two purposes); (2) forming a mask on the resist film; Pattern baking involves selectively irradiating light such as ultraviolet rays through a negative original plate to selectively create a pattern latent image. Burning process to increase etching resistance,■
The process is divided into four steps: drilling holes in the mask using etching solution.

A shadow mask has a large number of fine holes drilled in regular (two arrays), and the shape and size of each mask hole and overall unevenness determine the quality of the mask, and there are various factors that affect these. The resist film forming process will be explained below, but the required characteristics are resist film C: no defects such as bubbles or pinholes, and a uniform resist film thickness over the entire surface of the mask material (in the form of a band). The method for forming a resist film is as follows: ① Pour the mask material perpendicular to the floor (two sides) and flow-coat the resist agent from the top of the mask material, then dry to form a resist film. Method: - Pull the mask material upward from the horizontal position on the floor, and when pulling it up, apply the resist agent by dipping it in the resist agent or using a squeeze coater or rubber wiper, and then dry it to form a resist film. There are ways to do this.

However, in the former case, the resist film thickness is inevitably thinner at the upper part of the mask material than at the lower part due to flow coating due to gravity. As a result, in the thin resist film portion, the resist film eaves formed in the side niches are likely to be destroyed by the mechanical impact of the etching solution during subsequent etching, resulting in hole defects. In order to avoid this, it is possible to avoid using the thin upper part of the resist film when printing the mask pattern, but this greatly reduces the efficiency of using the mask material and leads to an increase in cost. Also, depending on the thickness of the resist film, the pattern dimensions printed on the resist film may differ from the original pattern dimensions.
In other words, the thicker the resist film is, the smaller the required pattern size tends to be due to the scattering of light passing through the pattern master in the resist film. The quality of the final mask unevenness deteriorates due to poor cutting of the edges of the remaining resist film. For these reasons, it is necessary to uniformly form a resist film having an optimum thickness over the entire surface of the mask material. In the latter case, since the resist agent is applied while pulling up, the difference in film thickness in the width direction of the mask material plate is extremely small compared to the former. However, after applying the resist agent until it dries,
The resist agent flows downward, and the condition of this flowing down changes due to slight differences in the flatness of the mask material, which tends to cause unevenness in the resist film thickness. Also, the resist agent flows down due to the presence of minute bubbles in the resist solution or the mask material. Occurred due to shaking during lifting.

When the foam is applied, unlike the former case, the resist agent does not flow away from the mask material, so it is trapped somewhere in the resist film that is formed, and this part becomes a defect in the mask hole.Furthermore, the resist film is pulled up. The drying oven is vertical (two wheels).This results in a chimney effect.
Hot air is blown up to the top of the drying oven, making it difficult to control the temperature in each part of the oven, resulting in film peeling due to insufficient drying, heat fogging due to overdrying, film unevenness due to resist agent dripping, and pinholes. It is easy to cause drawbacks such as:

[Purpose of the invention]

The present invention has been made in view of the above points (--), and an object of the present invention is to form a resist film having a uniform resist film thickness in the length and width directions of a metal plate and without pinholes or bubbles.

[Summary of the invention]

In the present invention, a resist agent is flow-coated from the upper end of a metal plate that is conveyed vertically in the width direction of the strip metal plate with respect to a horizontal floor surface, and after this, only the upper part of the metal plate is dried, and then a resist agent is applied again to the upper end of the metal plate. Then, the entire metal plate is dried to form a resist film having the desired thickness.

[Embodiments of the invention]

Figure 1 (2) Shows a process diagram of an embodiment of the present invention. Figure 1 (-
) shows a side view, and FIG. 1(b) shows a plan view.

A strip-shaped aluminum-killed steel thin plate is used as the mask material, and it is conveyed continuously in the horizontal direction with the width direction of the strip perpendicular to the horizontal floor (2).The mask material unwound from the unwinder 5 to remove rolling oil and rust prevention oil
Spray alkaline degreasing liquid at a temperature of 90 to 95 C at a concentration of 6% (LO3), then spray with industrial water and pure water to wash away the degreasing liquid (C). A second resist agent is applied to the cleaned mask material 6 (b), and the resist agent used is an aqueous solution consisting of milk casein alkaline deuterium chloride and ammonium. The resist agent is applied by flow coating using the difference in gravity using two forked nozzles from the upper end of the mask material, but it is desirable to provide nozzles at 2 to 8 locations to enable uniform application. After this, the first drying step (g)) (two people are required.As shown in Figure 2, the structure of the drying oven is such that the heater (2) ), for example, a sheathed heater or an infrastein heater is arranged, and a heat shield plate (3) is provided to prevent the lower part of the mask material (1) from drying out due to convection or radiation. ) is the position of the mask material (1) board +
It is preferable to use one that can be moved up and down.In this way, only the center to upper part of the width of the Nimask material board is dried, but this avoids the occurrence of uneven coating when applying the second resist agent. Therefore, it is desirable to control it to a half-dry state, and the ambient temperature is 50 to 60 C.
is good. Furthermore, in order to prevent a difference in the drying state of the resist film between the central part and the upper part, heaters (1) are arranged in blocks in the length direction and height direction of the drying oven, and the temperature can be adjusted for each block. Thereafter, the second resist agent application C) is started, which is carried out in the same manner as the second resist agent application C).

With this, the upper part from the center of the width of the mask material board is dry or half-dry (= there is, so the resist agent applied again will adhere again and the film thickness will increase, while the lower part is not dry and will be re-applied. As a result of the resist agent flowing down due to the force of gravity, a resist film with a uniform thickness is formed.In this state, the second drying (G) begins, and this second drying dries the entire surface of the mask material and achieves the desired purpose. A resist film with a thickness of YoC: A heater (
2) is arranged and the temperature can be controlled (2). After the second drying, the mask material is rewound again at the winding part (6). The length and temperature conditions of the first and second drying ovens are set according to the mask material. The flow rate and resist composition used (both vary and should be selected experimentally).

〔Effect of the invention〕

As described above (2) According to the present invention (2), a simple resist agent coating method C using gravity difference; It is possible to easily form a resist film that is free from defects such as irregular film thickness, bubbles, and pinholes.

[Brief explanation of the drawing]

Fig. 1(,) and Fig. 1(b) are side views and plan views showing the steps of the embodiment of the present invention, and Fig. 2 and Fig. 3 are the first and second drying ovens in Fig. 1. FIG. (1)...Mask material (2)...Heater (
3)...Heat shield plate representative, patent attorney Kensuke Norichika (and 1 other person) Figure 1 (Qn Figure 2 Figure 3 @

Claims (1)

[Claims] a step of forming a resist film on both sides of a strip-shaped metal plate; a step of selectively exposing the resist film through a predetermined negative master; and a step of developing the selectively exposed resist film.
In the method for manufacturing a shadow mask, the method includes at least a step of etching the metal plate, wherein the resist film forming step transports the band-shaped metal plate in a width direction substantially perpendicular to a horizontal floor surface; After flow-coating a resist agent from the upper end of the band-shaped metal plate, drying a portion of the resist film deposited on the metal plate corresponding to the upper part of the metal plate;
A method for producing a shadow mask, comprising the steps of: then flow-coating a resist agent again from the upper end of the metal strip, and drying the entire surface of the resist film adhered to the metal plate.