JPH06103888A - Manufacture of shadow mask for color cathode-ray tube - Google Patents

Abstract

PURPOSE:To provide with a high yield shadow mask having through-holes of predetermined shapes by eliminating the defects of etching resistant layers. CONSTITUTION:Resist films 16a, 16b each having exposed portions which correspond to a number of through holes in a shadow mask are formed on both sides of a plate-shaped shadow mask material 13. One side of the shadow mask material is etched to form a recess 9 and an etching resistor 23 is applied to the side of the shadow mask material in which the recess is formed, and is then heated and dried to form an etching resistant layer 30. Thereafter the other side is etched to form a recess 10. At this time, the etching resistor applied to one side of the shadow mask material is indirectly heated and dried from the other side of the shadow mask material to form an etching resistant layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a shadow mask for a color cathode ray tube, and more particularly to a method for producing a shadow mask for a color cathode ray tube in which both sides of a shadow mask material are separately etched in two stages.

[0002]

2. Description of the Related Art A color cathode-ray tube has, as shown in FIG. 3, an envelope composed of a panel 1 and a funnel 2 integrally joined to the panel 1, and blue and green formed on the inner surface of the panel 1. A shadow mask 4 is attached to the inside of the phosphor screen 3 which faces the phosphor screen 3 composed of a three-color phosphor layer which emits red light.

This shadow mask 4 selects three electron beams 7B, 7G, 7R emitted from an electron gun 6 arranged in a neck 5 of a funnel 2 and selects 3 of the phosphor screens 3.
This is for correctly landing on the color phosphor layer, and a large number of through holes are formed on the plate surface facing the phosphor screen 3 corresponding to the three-color phosphor layer. Usually, this through hole is, as shown in FIG. 4, the small concave hole 9 formed on one surface of the plate-shaped shadow mask material, that is, the surface on the electron gun side, and the other surface, that is, the phosphor screen. It is composed of a large concave hole 10 formed on the opposing surface, and is formed in a shape having a minimum diameter portion 11 (diameter d) for regulating the diameter of the through hole at a position close to one surface thereof.

By the way, color cathode ray tubes currently in practical use include color cathode ray tubes for monitors and displays in addition to general color cathode ray tubes for receiving television images. In particular, in this color cathode ray tube for monitors and displays, in order to display fine images and characters, a shadow mask with more precise and fine through holes is used than the shadow mask of a general color television tube for receiving television. Required.

As a method for manufacturing the above shadow mask, there is a conventional method called a simultaneous etching method shown in FIG. According to this method, as shown in (a), a photosensitive agent is applied to both surfaces of a plate-shaped shadow mask material 13 whose both surfaces are cleaned, and dried to form a photosensitive film 14. Next, as shown in (b), a pair of negative master plates 15a, 15b having different patterns of different sizes corresponding to the respective concave holes of the through holes of the shadow mask are formed on the photosensitive film 14 on both sides thereof. Exposure is performed in close contact with each other, and the patterns of the negative master plates 15a and 15b are printed. Next, as shown in (c), the exposed photosensitive film 14 having the above pattern is developed to remove the unexposed portion, and the portion where the through holes of the shadow mask are formed is the exposed portion of the shadow mask material 13. Resist films 16a and 16b are formed. Next, as shown in (d), the shadow mask material 13 on which the resist films 16a and 16b are formed is simultaneously etched from both sides, and a small recess 9 is formed in the exposed portion of the shadow mask material 13.
And a through hole 17 composed of the large recessed hole 10 is formed. After that, the resist films 16a and 16b on both surfaces of the shadow mask material 13 in which the through holes 17 are formed are removed to form a flat mask 18 having a flat plate shape as shown in FIG.

However, when a shadow mask is manufactured by this method, the shape and dimensional accuracy of the through hole 17 deteriorates as the diameter of the through hole becomes smaller, so that the shadow mask used in a color display tube or the like for displaying a fine image becomes like a shadow mask. It is difficult to manufacture a high-definition shadow mask whose through hole diameter is smaller than the plate thickness of the shadow mask material.

Therefore, a method called a two-step etching method shown in FIG. 6 has been developed as a method of manufacturing a shadow mask having a through hole diameter smaller than the plate thickness of the shadow mask material.

This two-step etching method is similar to the above-mentioned simultaneous etching method (see FIGS. 5A to 5C), in which a photosensitive agent is applied to both surfaces of a plate-shaped shadow mask material 13 whose both surfaces are cleaned. Then, the photosensitive film 14 is formed by drying, and a pair of negative master plates 15a having different sizes of large and small patterns corresponding to the concave holes of the through holes of the shadow mask are formed on the photosensitive films 14 on both sides thereof.
, 15b are closely contacted and exposed, and the patterns of the negative masters 15a, 15b are baked, and then developed to remove the unexposed areas, and the exposed areas of the shadow mask material 13 are the areas where the through holes of the shadow mask are formed. Resist films 16a and 16b are formed.
Next, as shown in FIG. 6A, a corrosion masking film 20a is adhered on the resist film 16b (resist film for forming large recesses) on the other surface for forming the large recesses, and a shadow mask is formed. The other surface of the material 13 is covered and one surface of the shadow mask material 13 on which the resist 16a (resist for forming a small recess) is formed is etched to expose the shadow mask material 13 on this one surface. Form small recesses 9 (pre-stage etching). Next, as shown in (b), the resist for forming small recesses on one surface is peeled off. Next, as shown in (c), one side of the small-hole forming resist that has been peeled off is coated with an etching resistance agent made of, for example, an epoxy resin so as to be embedded in the small concave hole 9, and this coating is applied. The etching resistance agent is dried to form the etching resistance layer 21. Then, the anticorrosion film 20a covering the other surface of the shadow mask material 13 is removed, and the anticorrosion film 20b is formed on the one surface where the etching resistance layer 21 is formed.
As shown in (d), the other surface of the corrosion-preventing film that has been peeled off is etched, and the exposed surface of the shadow mask material 13 on the other surface is passed through the small recess. A large concave hole 10 is formed (post-stage etching). Thereafter, as shown in (e), the corrosion prevention film covering the one surface is removed, and the etching resistance layer formed on the one surface is removed. Thereafter, as shown in (f), the large concave hole forming resist is removed to form a flat mask 18 in the form of a flat plate having a through hole 17 composed of the small concave hole 9 and the large concave hole 10.

However, in the above conventional two-step etching method,
As shown in FIG. 7, the etching resistance agent applied so as to be embedded in the small concave hole 9 on one surface side of the shadow mask material 13.
The drying of 23 is performed by directly facing one surface coated with the etching resistance agent 23 to a heat source 24 such as Infrastein (trade name), sheath heater, and quartz heater installed in the drying furnace. . Therefore, the etching resistance agent 23 applied to one surface side of the shadow mask material 13
As shown in FIG. 7 (a), in the initial stage of drying, bubbles 25 are generated in the small recess 9 and the like. Then, it is dried without being defoamed, and as shown in FIG. 7B, a defect portion such as the etching resistance layer 21 is thin or not formed.
26. As a result, in the subsequent etching, the shape of the through hole changes at the defective portion 26 of the etching resistance layer 21,
There is a problem of being defective.

[0010]

As described above, as a method of manufacturing a shadow mask having a through hole diameter smaller than the plate thickness of the shadow mask material, there is a two-step etching method in which etching is performed in two steps. In this manufacturing method,
A small concave hole forming resist and a large concave hole forming resist are formed on both surfaces of the shadow mask material, and one surface on which the small hole forming resist is formed is etched to form a small concave hole as the previous etching. Then, on one surface where this small recess is formed, apply an etching resistance agent so as to be embedded in the small recess and dry it to form an etching resistance layer, then form a large recess as the latter etching. The other surface on which the resist for use is formed is etched to form a large concave hole communicating with the small concave hole to form a through hole.

However, in the conventional two-step etching method, the etching resist applied on one side of the shadow mask material so as to be embedded in the small recessed hole is dried by placing one side of the shadow mask material in a drying furnace. Infrastein, sheathed heater,
It is performed by directly facing a heat source such as a quartz heater. Therefore, the etching resistance agent applied to one surface side of the shadow mask material, in the initial stage of drying,
Bubbles are generated in the small recesses and the like, and they are dried without being defoamed, resulting in defects such as thin or not formed etching resistant layer. As a result, in the subsequent etching, the shape of the through hole changes at the defective portion of the etching resistance layer, which causes a problem.

The present invention has been made in order to solve the above-mentioned problems, and in a method of manufacturing a shadow mask by a two-step etching method, a small concave hole is formed on one surface by etching in the previous step, and then coating is performed. The etching resist agent is completely filled in the small concave hole to form a defect-free etching resistance layer, and to eliminate the defect of the through hole shape caused by the defect of the etching resistance layer.

[0013]

A resist film having exposed portions corresponding to a large number of through holes of a shadow mask is formed on both sides of a plate-shaped shadow mask material, and one of the shadow mask materials on which the resist film is formed is formed. Surface is etched to form a concave hole in the exposed portion of this one surface, and an etching resistance agent is applied to one surface of the shadow mask material in which the concave hole is formed, and then it is heated and dried to form an etching resistance layer. Of the shadow mask material for a color cathode-ray tube, in which the other surface of the shadow mask material on which the etching resistance layer is formed is etched to form a concave hole communicating with the concave hole of the one surface on the exposed portion of the other surface. In the manufacturing method, the etching resistance agent applied to one surface of the shadow mask material is indirectly heated and dried from the other surface side of the shadow mask material to etch resistance. It was to form a.

[0014]

As described above, after forming a concave hole on one surface of the shadow mask material, the etching resistance agent applied to this one surface is indirectly heated and dried from the other surface side of the shadow mask material. When the etching resistance layer is formed by using the above method, it becomes easy to control the drying rate of the etching resistance agent applied to one surface of the etching resistance layer, and bubbles are generated in the concave holes in the initial stage of conventional drying, and the layer is dried without being defoamed. Therefore, it is possible to eliminate the defects of the etching resistance layer that are caused.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the drawings.

FIG. 1 shows steps for explaining a method of manufacturing a shadow mask which is one of the embodiments. Figure 1
As shown in (a), a long plate-shaped shadow mask material 13
Is washed, a photosensitive agent is applied to both surfaces of the cleaned shadow mask material 13 and dried to form a photosensitive film 14. Next, as shown in (b), a pair of negative master plates 15a, 15b having different patterns of different sizes corresponding to the concave holes of the through holes of the shadow mask are adhered to the photosensitive film 14 on both sides thereof. Exposure, and print the pattern of the negative master plates 15a and 15b. Next, as shown in (c), a resist having the exposed portion of the shadow mask material as the exposed portion of the shadow mask material is developed by removing the unexposed portion by developing the photosensitive film 14 having the above pattern baked. The films 16a and 16b are formed. The resist film 16a is a resist film for forming small recesses, and the exposed portion of one surface of the shadow mask material 13 is small corresponding to the pattern of the negative original plate 15a. In addition, the resist film 16
b is a resist film for forming large concave holes, and the exposed portion of the other surface of the shadow mask material 13 is formed to be large corresponding to the pattern of the negative original plate 15b. Then the same (d)
As shown in FIG. 3, a corrosion prevention film 20a is attached on the resist film 16b formed on the other surface of the shadow mask material 13 to cover the other surface of the shadow mask material 13 and form the small hole forming resist 16a. Formed shadow mask material 13
One of the surfaces faces downward, and the etching liquid is sprayed on the one surface facing downward to form a small recessed hole 9 in the exposed portion of the shadow mask material on the one surface side (pre-stage etching).

Next, as shown in FIG.
The shadow mask material 13 on which 9 is formed is washed with water, and an alkaline solution is further sprayed on one surface of the material to remove the small hole forming resist on the one surface side. The anticorrosion film covering the other side is then removed.

Next, as shown in (f), an etching resisting agent 23 made of, for example, an epoxy resin is applied to the small concave hole on one surface of the shadow mask material 13 from which the small concave hole forming resist is peeled off. Apply so that it is embedded. Then, as shown in (g), it is heated and dried to form an etching resistance layer.
Forming 30. Drying of the etching resistance agent 23 applied to one surface of the shadow mask material 13 is performed in a heating and drying furnace, and as shown in FIG. 2, a plurality of infrasteins installed in parallel in the drying furnace. The heat source 24 is used to indirectly heat the back surface, that is, the other surface side of the shadow mask material 13.

The shadow mask material 13 on which the etching resistance layer 30 is formed as described above is then coated with the corrosion prevention film 20b on one surface thereof as shown in FIG. The other surface of the stripped surface is directed downward, and the etching solution is sprayed on the other surface facing downward, and the exposed portion of the shadow mask material 13 on the other surface side is passed through the small concave hole 9 on the one surface side. A large concave hole 10 is formed (post-stage etching).

Thereafter, it is washed with water, and as shown in (i), the corrosion prevention film on the one surface is removed. Then, as shown in (j), an alkaline solution is sprayed to swell the etching resistance layer formed on one surface,
Further, hot water is sprayed to remove the etching resistance layer floating from one surface by swelling. After that, the large concave hole forming resist 16b on the other surface is sprayed and removed with an alkaline solution, washed with water and dried, and as shown in FIG. A flat mask 18 having holes 17 is formed.

By the way, when the etching resistance layer 30 is formed on one surface of the shadow mask material 13 in which the small recesses 9 are formed by the preceding etching as described above, it is applied so as to be embedded in the small recesses 9. When the etching resistance agent 23 is indirectly heated and dried from the back side, it becomes easy to control the drying rate of the etching resistance agent 23 applied to one side, and the etching resistance agent 23 directly applied from one side where the conventional etching resistance agent is applied. As a result of the heating, the defects in the etching resistance agent caused by the air bubbles generated in the small concave holes in the initial stage of drying and caused by the drying without defoaming can be eliminated. It is possible to prevent the change in the shape of the through hole caused in the above step, and it is possible to manufacture a shadow mask having a through hole of a predetermined shape with a good yield.

[0022]

EFFECTS OF THE INVENTION An etching resistance agent is applied to one surface of a shadow mask material in which a concave hole is formed by the preceding etching, and the etching resistance agent applied to this one surface is applied to the other surface side of the shadow mask material. When the etching resistance layer is formed by heating and drying indirectly from, it becomes easy to control the drying rate of the etching resistance agent applied to one surface of the etching resistance layer. , Bubbles are generated in the concave holes in the initial stage of drying, and it is possible to eliminate the defects of the etching resistance agent caused by drying without being degassed, and a shadow mask consisting of through holes of a predetermined shape can be produced with good yield. It can be manufactured.

[Brief description of drawings]

1A to 1K are process drawings for explaining a method for manufacturing a shadow mask according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a method of heating and drying the etching resistance agent applied to one surface of the shadow mask material.

FIG. 3 is a diagram showing a configuration of a color CRT.

FIG. 4 is a diagram showing a through hole shape of the shadow mask.

5A to 5E are process diagrams for explaining a conventional shadow mask manufacturing method by a simultaneous etching method.

6A to 6F are process diagrams for explaining a conventional method of manufacturing a shadow mask by a two-step etching method.

FIG. 7 is a diagram for explaining a method of heating and drying an etching resistance agent applied to one surface of a shadow mask material in a conventional method of manufacturing a shadow mask by a two-step etching method.

FIGS. 8A and 8B are diagrams for explaining the generation of defects in the etching resistance layer in the conventional method of heating and drying the etching resistance agent.

[Explanation of reference numerals] 9 ... Small concave hole 10 ... Large concave hole 13 ... Shadow mask material 14 ... Photosensitive film 15a. 15b ... Negative original 16a. 16b ... Resist film 17 ... Through hole 23 ... Etching resistance agent 24 ... Heat source 30 ... Etching resistance layer

Claims (1)

[Claims] 1. A step of forming a resist film having exposed portions corresponding to a large number of through holes of a shadow mask on both surfaces of a plate-shaped shadow mask material, and one surface of the shadow mask material on which the resist film is formed. Etching step to form a concave hole in the exposed portion of this one surface, and after applying an etching resistance agent to one surface of the shadow mask material in which the concave hole is formed, the shadow mask material The step of indirectly heating and drying from the other surface side to form the etching resistance layer, and the other surface of the shadow mask material on which the etching resistance layer is formed is etched to form an exposed portion of the other surface. A method of manufacturing a shadow mask for a color cathode ray tube, comprising: a post-etching step of forming a concave hole communicating with a concave hole on one surface.