JPS5971239A - Production method of shadow mask - Google Patents

Abstract

PURPOSE:To produce a shadow mask perforated with fine and precise holes and having excellent quality by corroding a mask raw material having photosensitive films retained on both main faces except a small hole forming section and a large hole forming section in two corrosion tanks with different corrosion liquid shock forces. CONSTITUTION:A shadow mask raw material 11 with photosensitive films retained on both main faces except a small hole forming section with a hole width of d3 and a large hole forming section with a hole width of d4 respectively is allowed to pass through the first corrosion tank 21 in the advance direction of an arrow 20. A corrosion liquid with a large preset shock force is sprayed through a spray nozzle 21a for corrosion in this tank 21, but since the hood of photosensitive films 12, 13 generated at this time is small, the films, 12, 13 can sufficiently withstand. Next, it is allowed to pass through the second corrosion tank 22, and a corrosion liquid with a small preset shock force is injected through a nozzle so as not to collapse the hood of the photosensitive films 12, 13 which has grown larger. Next, it is sent to a water washing tank 23 to remove the photosensitive films 12, 13 and obtain a flat shadow mask.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a shadow mask, and in particular, uses a thick shadow mask material with a plate thickness of 0.20 to 0.40 mm, and removes chloride during the etching process. [Technical Background of the Invention] In recent years, television receivers have become increasingly popular with video cameras. The color cathode ray tubes built into television receivers are used as one of the components of television and audio equipment, and are required to be simple and functional in terms of design. The screen is changing to one that is flat, has no image breaks at the four corners, and is easier to see.On the other hand, as is well known, the most important characteristics of the shadow mask built into a color cathode ray tube are: The electron beam emitted from the electron gun passes through the electron beam passage hole of the shadow mask and accurately strikes the phosphor layer that emits light in each color forming the phosphor surface. However, as time passes after the shadow mask is turned on, the temperature of the shadow mask increases due to the impact of the electron beam, causing thermal expansion, and as a result, the position of the electron beam spot and the phosphor layer no longer match. , a so-called mislanding occurs and a color shift phenomenon occurs.

This color shift phenomenon is more severe in the case of a flat color cathode ray tube than in a spherical color cathode ray tube, and there is a problem in that even minute deformations of the shadow mask can cause the color shift phenomenon to occur significantly.

For example, conventional spherical shape, 19V1 mini neck type 90
The inner surface of the face plate of the ° deflection color cathode ray tube has a radius of approximately 800 mmH, whereas the inner surface of the face plate of the flat, 20v1 mini-neck type 90° deflection color cathode ray tube has a radius of approximately 1350 mmR.

Therefore, the curvature of the shadow mask is also determined according to the radius of the inner surface of the face plate, and in the former case, the radius is 11
760 mmR, and the latter approximately 1300 mmR.

According to the inventors' experiments, the thickness of the conventional shadow mask material is about 0.18 mmt to about 0.30±0.10 m.
It was confirmed that by significantly increasing the thickness to mt, it is possible to reduce the amount of deformation caused by thermal expansion of the shadow mask, and also to make it stronger against physical impact forces.

However, when corroding a thick shadow mask material, there are the following difficulties.

In other words, it takes approximately twice as long to corrode the shadow mask material (1) as shown in FIGS. The photoresist films (2) and (3) formed on the amphibious surfaces are each provided with exposed portions of diameter (di) (d2), and in the etching process, shallow holes (4□) (51) are formed.
A slightly deeper hole (42) (52), an even deeper hole (
43) When drilling (53) and drilling an electron beam passage hole (6) having an opening diameter of diameter (DI) (D2), side wall corrosion in the direction of arrow (7) due to corrosive liquid may occur. , the resulting photoresist film (2) of (Dl-dl) and (D2-d2)
21X31) is generated in the aperture of (3), and the impact force caused by the spray of corrosive liquid causes deformed parts (8) and defective parts (9) in the aperture 21) (31), and finally the electron beam passage hole There is a problem that the shape of (6) is deteriorated, resulting in a defective shadow mask.

[Purpose of the invention]

The present invention was made in view of the above-mentioned problems, and is suitable for use in flat color cathode ray tubes.
It is an object of the present invention to provide a method for manufacturing a shadow mask, which has a wall thickness of mmt and is capable of forming fine and precise electron beam passage holes of good quality.

[Summary of the invention]

That is, in the present invention, a shadow mask material in which a photoresist film remains on both surfaces except for the small hole forming part and the large hole forming part is sprayed with an etching solution at a predetermined impact force in an etching bath, In a method for manufacturing a shadow mask in which an electron beam passage hole is formed, the etching tank is divided into a first etching tank and a second etching tank from the direction of movement of the shadow mask material, and the etching tank is divided into a first etching tank and a second etching tank. In the tank, the predetermined impact force is large, and in the second corrosion tank, the predetermined impact force is small, and the thickness of the shadow mask material is 0.
, 20~0.40 mmt, photoresist film thickness 8~12μ
m, the predetermined impact force of the first corrosion tank is 5 to 10 l/lt/l
, the predetermined impact force of the second corrosion tank is 2.5 to 59/l, r
1 is considered as an embodiment.

[Embodiments of the invention]

Next, one embodiment of the present invention will be described with reference to FIGS. 5 to 11.

First, a long 0.3 mm thick mild steel plate was prepared as a shadow mask material, and after cleaning both surfaces, a photosensitive liquid containing milk casein as a main component was applied to the shadow mask material.
That is, ammonium dichromate is used as a photosensitizer, and approximately 1 liter is added by weight to casein to give a specific gravity of 1.040 (
A photosensitive solution adjusted to 1.028 (conventionally) is applied using a vertical dipping method and dried in an atmosphere of approximately 100°C for approximately 10 minutes to form a photoresist film approximately 10 μm thick (previously 5 μm). . Next, in the exposure process, the hole width (d3) shown in Fig. 5 is 0.060 mm (previously 0.115 mm) and the bridge width (bl) is 0.235 m.
m (conventionally 0.200 tnm) small hole side negative/mean (101), hole width (d4) shown in Figure 6 as the large hole part is 0.410 mm (conventionally 0.405 mm), bridge width (b2 ) is 0.150mm (previously 0.125mm
) are closely placed on the photoresist film, and exposed with a 5KW mercury lamp from a distance of about 1m.
Perform a minute exposure. Next, use warm pure water at about 40℃ at a pressure of 1~
Developing is carried out for 1 minute at a spray pressure of /d, dried for 2 minutes in an atmosphere of 150°C, and burned for 15 minutes in an atmosphere of 200°C. In this way, a shadow mask is formed in which the α step of the photoresist film a remains on both surfaces shown in FIG. 7, except for the small hole forming part with the hole width (d3) and the large hole forming part with the hole width (d4). Material (11) is completed.

Next, the corrosion process will be explained with reference to Figs.
From the advancing direction of the direction, the first corrosion tank Qη the second corrosion tank (a), the washing tank (c)), the first corrosion tank 0), the ninth
The holes are drilled from the shallow holes (141) (151) shown in the figure to the slightly deeper holes (142) (152) shown in FIG. Photoresist film 021 where side wall corrosion in direction 171) does not progress much.
(13) does not emit much 12z) (13t), so even if the impact force applied from the spray nozzle (21a) to the photoresist film 03) is 5 to 102/-, it is only about 10μ.
The photoresist film H (13) of m has sufficient durability. This 5-1
An impact force of 02/- was obtained using EX-430 manufactured by Danken Kogyo at a spray pressure of 1.5 to 2.5 Kg and a distance of 300 mm between the nozzle (21a) and the shadow mask material a]).

In this case, the temperature of the corrosive liquid was 67°C, and a ferric chloride solution with a specific gravity of 1.467 was used to drill for about 6 minutes (142 x 152) to the deeper holes (143) (153) in Figure 1. The electron beam passing hole QGI is obtained, but at this time the side wall corrosion in the direction of the arrow (172) progresses and the photoresist film (12)
) (13 diameters of 122 x 132) gradually come out, so the impact force that the etching liquid gives to the photosensitive film from the spray nozzle (22a) is reduced to 25 to 5 r, which is about half of that of the first etching tank.
/ctA, and a corrosive liquid having the same composition and temperature is sprayed for about 6 minutes to complete the corrosive process.

Electron beam passage hole (L6) drilled in this way
3) of the slot width on the electron gun side, that is, on the small hole side, is 0.200 m.
m (Same as before) Slot width on the fluorescent surface side, that is, on the large hole side (D
4) is 0.580 mm (previously 0.510 ?Fl
? ? 1) Bridge width is 0.120 mm (same as conventional), and side wall corrosion amount (Da d3) is 0.140
mm (conventionally 0.085 mm), (D4-d4) is 0.170 mm (conventionally 0.10.5 mm), which is much longer than the conventional one (122) (132), but the second In the corrosion tank (A), the photoresist film (12 (13)
Since the material is thick and the impact force is further reduced, it was possible to drill a high-quality electron beam passage hole (IQ) without any deformation or damage of 122) (132) until the end of the corrosion process. .

Next, the photosensitive film is removed by washing in a water washing tank (a) to obtain a flat mask.

Although the above embodiment has been described with respect to a rectangular electron beam passage hole, it goes without saying that the same applies to a circular electron beam passage hole.

〔Effect of the invention〕

As described above, according to the present invention, even when the thickness of the shadow mask material is increased, the thickness of the photosensitive film can be increased, and furthermore, the corrosion can be performed in two corrosion tanks with different impact force conditions. It is possible to form a high quality shadow mask suitable for color cathode ray tubes, and its industrial value is extremely large.

[Brief explanation of drawings]

1 to 4 are explanatory cross-sectional views showing a conventional method for manufacturing a shadow mask in the order of steps, and FIGS. 5 to 11 are diagrams showing an embodiment of the method for manufacturing a shadow mask according to the present invention. , FIG. 5 is an explanatory diagram of the negative pattern on the small hole side, FIG. 6 is an explanatory diagram of the negative pattern on the large hole side, and FIG. 7 is an explanatory sectional view showing the relationship between the shadow mask material and the photoresist film before the etching process.
FIG. 8 is a diagram of the corrosion apparatus, and FIGS. 9 to 11 are explanatory cross-sectional views showing the corrosion state in the corrosion process in the order of steps. 1.11...Shadow mask material 2.3.12.13...Photoresist film 21.31.121.131.122.132...Eave 41.51.141.151...Shallow hole 42 ．．
52.142. ．． 152...Slightly deep hole 43.53
．． 143.153...Deeper hole 6.16...Electron beam passing hole 21--First corrosion tank 22...Second corrosion tank 23...Water tank agent Patent attorney I Top - Male

Claims (2)

[Claims] (1) An etching solution is sprayed with a predetermined impact force in an etching tank using a spray method onto the shadow mask material, which has a photoresist film remaining on both sides except for the small and large hole forming areas, and the electron beam passes through the shadow mask material. In the method for manufacturing a shadow mask, the method comprises: dividing the etching tank into a first etching tank and a second etching tank from the direction of movement of the shadow mask material; A method for producing a shadow mask, characterized in that the predetermined impact force is increased in the bath, and the predetermined impact force is decreased in the second corrosion tank. (2) The thickness of the shadow mask material is 0.20~0.
40 mmt, the photoresist film is 8 to 12 μm, the first etching tank has a predetermined impact force of 5 to 10 t/cr/l, and the second etching tank has a predetermined impact force of 2.5 to 10 t/-. A method for manufacturing a shadow mask according to claim 1.