JP2746876B2 - Manufacturing method of shadow mask - Google Patents

Description

The present invention relates to a method for manufacturing a shadow mask used for a color picture tube. (Prior Art) In general, a shadow mask used for a color picture tube is arranged in close proximity to a phosphor screen composed of groups of different emission colors, and has a color-specific function through a large number of regularly arranged apertures. It is an important member to play. In particular, the diameter and cross-sectional shape of these apertures have a great effect on the above-described color-specific functions, and apertures having an aperture diameter smaller than the thickness of the shadow mask and having a uniform cross-sectional shape are required. You. Usually, when manufacturing such a shadow mask, a large number of holes are formed by etching from a strip-shaped thin metal plate. At this time, the opening area of the surface of the metal sheet on the phosphor screen side is larger than the diameter of the opening to be bored, particularly the cross-sectional shape thereof, in comparison with the diameter of the opening penetrating in the thickness direction. The hole area on the surface of the metal sheet on the electron gun side is substantially equal to the diameter of the hole penetrating in the thickness direction, and smaller than the hole area on the phosphor screen side (hereinafter, this is referred to as “hole”). Referred to as "pores"). When an opening having such a complicated cross-sectional shape is formed by etching, the accuracy and reproducibility decrease as the required opening diameter decreases, and an opening diameter smaller than the thickness of the shadow mask is obtained. It is difficult. By the way, as a method for obtaining a shadow mask having an opening diameter smaller than such a plate thickness, Japanese Patent Application Laid-Open No. 60-70185 discloses the following method for manufacturing a shadow mask. That is, as shown in FIG. 3 and FIG. 4, the metal surface which forms the small holes 3 of the metal sheet 2 covered with the resist layer 1 having an exposed metal surface and the other portions having etching resistance is defined as a lower surface, The metal surface forming the large hole 4 is the upper surface (FIG. 3 (a)), and a protective film 5 such as polyethylene, polypropylene, polyvinyl chloride or polyester is attached to the large hole 4 located on the upper surface. The etching solution 6 is sprayed only on the side of the small hole 3 located on the lower side surface, and etching is performed until the intended concave portion 7 is formed (FIG. 3 (b)) (FIG. 4 (a)), followed by washing with water. (FIG. 4 (b)). Next, while the protective film 5 is adhered to the large hole 4 side, the remaining resist layer 1 on the small hole 4 side is peeled off (fourth step).
(FIG. 4 (c)) and washing with water (FIG. 4 (d)). Next, the metal thin plate 2 is turned over so that the concave portion 7 formed by the preceding etching is used as an upper surface (FIG. 3 (c)), and an etching resistive material is applied to this surface by a roller coater or a knife coat (fourth). (FIG. 4E) and drying (FIG. 4F) to form an etching resistance layer 8 (FIG. 3D). Next, the protective film 5 on the side of the large hole 4 is peeled off, and etching is performed by spraying the etching solution 6a only on the side of the large hole 4 located on the lower surface of the metal thin plate 2 (FIG. 4 (g)). The large hole 4 side recess 9 reaches the resistive layer 8 to obtain a shadow mask opening 10 having a desired size. Thereafter, the resist layer 1 and the etching resistance layer 8 are removed, and the step of forming the openings 10 of the shadow mask is completed. (Problems to be Solved by the Invention) However, in such a method for manufacturing a shadow mask, when the etching resistance material is applied to the small hole side, the protective film attached to the large hole side is washed with water until then. In the case where the dirt that could not be removed remains, the dirt is mixed into the etching resistance material, and when the etching resistance material is circulated, the purity of the etching resistance material decreases, and Since the thickness of the protective film varies to change the thickness of the etching resistance layer, the etching resistance of the etching resistance layer is adversely affected, and the quality of the shadow mask is reduced. When an etching resistance layer is formed on the small hole side, the fifth
As shown in the figure, the thickness of the etching resistance layer is different between the upper portion a of the thin metal plate, the bottom portion b of the concave portion, and the boundary c between the upper portion a of the thin metal plate and the concave portion b. turn into. As a result, the boundary c is a portion that is greatly affected by the above-described variation in the thickness of the etching resistance layer. That is, in the state where the large hole side recess reaches the etching resistance layer due to the large hole etching, the film strength of the etching resistance layer is reduced due to the above-described variation in the thickness of the boundary c, and the etching solution This causes the permeation into the surface of the thin metal plate, which tends to cause a defect in the opening shape of the shadow mask. Furthermore, since the etching solution is sprayed only on the lower side of the thin metal plate when etching the large hole side, the thin metal plate vibrates up and down, causing the distance between the thin metal plate and the spray nozzle to fluctuate, and performing uniform etching. There was also a problem that it became impossible. The present invention has been made in order to solve the above-described problems, and provides a method for manufacturing a shadow mask capable of obtaining an opening having a smaller diameter and a uniform cross-sectional shape than the thickness of a thin metal plate. It is an object. [Constitution of the Invention] (Means for Solving the Problems) The present invention achieves the above object by etching one surface of a metal sheet through a resist layer having small holes formed therein. A first etching step of forming a large number of recesses on one surface of the metal sheet, and a resist layer removing step of removing a resist layer on one surface of the metal sheet etched by the first etching step A resistive layer forming step of applying a resistive material having etching resistance on the surface of the metal sheet from which the resist layer has been removed in the resist layer removing step and drying the resistive layer to form a resistive layer; and The formed resistance layer has a surface slightly depressed along the concave portion, and an adhesive layer or an adhesive layer is formed on the surface of the resistance layer in a form having a space between the depression and the resistance layer protective film. And a second etching step of etching the other surface of the thin metal plate through a resist layer having a large opening to penetrate to the concave portion. And a residue removing step of removing the remaining resistive layer protective film, resistive layer and resist layer. (Function) In the method for producing a shadow mask of the present invention, after forming a resistive layer, a resistive layer protective film is attached to the surface of the resistive layer via an adhesive layer or an adhesive layer.
A method of manufacturing a shadow mask capable of obtaining a hole having a diameter smaller than the thickness of a thin metal plate and having a uniform cross-sectional shape, because it is possible to prevent a decrease in the film strength of the resistance layer and prevent the penetration of an etching solution. Can be provided. (Example) Hereinafter, a method for manufacturing a shadow mask according to an example of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a metal sheet in each step according to an embodiment of the present invention, and FIG. 2 is a schematic view showing each step. First, as a metal thin plate 11 used as a material for the shadow mask, a smooth aluminum killed low carbon steel plate having a thickness of 0.13 mm is used, and a photosensitive solution comprising milk caseinate and ammonium dichromate is applied to both main surfaces and dried. To form a resist layer 12 of about 8 μm. Next, a negative plate having a circular image of about 80 μm was placed on one main surface of the metal sheet 11 and a negative plate having a circular image of about 150 μm was placed in close contact with the corresponding position of the other main surface, and 5 KW of mercury Exposure for 30 seconds from a distance of 1m using a lamp. Then, 1 kg / cm ³ with 40 ° C warm water
The unexposed and uncured portion of the resist layer 12 is dissolved and removed by the spray pressure described above to expose metal surfaces corresponding to the small hole 13 forming portion and the large hole 14 forming portion (FIG. 1 (a)). Thereafter, in order to improve the etching resistance of the remaining resist layer 12 and the adhesion strength to the metal sheet 11, the substrate is dried in an atmosphere at 150 ° C. for about 2 minutes and burned in an atmosphere at 200 ° C. or more for about 2 minutes.
Next, an organic synthetic protection film 15 such as polyethylene, polypropylene, polyvinyl chloride, or polyester is attached to the large hole 14 located on the upper surface of the metal thin plate 11 (first).
(FIG. 2 (b)), after the etching solution 16 is sprayed only on the side of the small hole 13 located below the thin metal plate 11, and etching is performed until the intended concave portion 17 is formed (FIG. 2 (a)). Then, it is washed with water (FIG. 2 (b)). The etching solution 16 used here is a ferric chloride solution having a specific gravity of 1.45 to 1.49 and a liquid temperature of 50 to 70 ° C., and is etched at a spray pressure of 1.5 to 2.5 kg / cm ³ . Next, while the protective film 15 is adhered to the large hole 14 side, a sodium hydroxide solution having a concentration of 15% and a solution temperature of 60 ° C. is sprayed from the small hole 13 side, and the remaining resist layer 12 on the small hole 13 side is peeled off. 2 (c)), and wash with water (FIG. 2 (d)). Next, the metal thin plate 11 is inverted (FIG. 1 (c)), the protective film 15 is peeled off, and the small holes 13 formed by the previous etching are removed.
The concave portion 17 on the side is set to the upper side, and an etching resistive material such as paraffin, petroleum pitch, lacquer, alkali milk caseinate, polyvinyl alcohol, epoxy dispersion resin or alkyd resin is applied to this surface with a knife coater (No. 2 (e), the etching resistance layer 18 is formed by applying an etching resistance material to the depression 17 on the side of the small hole 13 so as to leave a small depression 17a and drying it (FIG. 2 (f)). FIG. 1 (d)). Etching resistance layer 18
The coating film thickness is 5 to 5 on the surface of the metal sheet 11 other than the recess 17.
A range of 10 μm is appropriate. After the formation of the etching resistance layer 18, a resistance layer protection film 19 having an adhesive property on one side such as polyethylene, polypropylene, polyvinyl chloride, or polyester is attached on the surface of the etching resistance layer 18 (FIG. 1 (e) )). Next, the etching solution 16a made of ferric chloride is sprayed onto both main surfaces of the metal sheet 11 to perform etching (FIG. 2 (g)), so that the large hole 14 side recess 20 reaches the etching resistance layer 18. Thus, a shadow mask opening 20a having a desired size is obtained (FIG. 1 (f)). Next, the resistive layer protective film 19 which was adhered and protected to the etching resistive layer 18 was peeled off (FIG. 2 (h)), and then the etching resistive layer 18 and the resist layer were removed.
12 (FIG. 2 (i)) Opening 20 of the shadow mask
The formation process of a is completed. Thus, according to the above-described embodiment, before forming the etching resistance layer 18 in the concave portion 17 formed on the small hole 13 side, the large hole 14 is formed.
By removing the protective film 15 on the side, it is possible to eliminate contamination and the like in the subsequent process, so that a highly pure etching resistance material can be constantly used, and the thickness of the etching resistance layer 18 can be made uniform. Can be. Also, after forming the etching resistance layer 18 in the concave portion 17 formed on the side of the small hole 13, a resistance layer protection film 19 having an adhesive property on one surface is attached on the surface of the etching resistance layer 18 to protect the etching resistance layer 18. By doing so, it is possible to prevent a decrease in film strength due to a variation in the thickness of the etching resistance layer 18 and to prevent the penetration of the etching solution 16a into the etching resistance layer 18, so that the metal thin plate has a diameter smaller than the plate thickness and is uniform. It is possible to obtain a hole having a different shape. Further, since the concave portion 17 on the side of the small hole 13 between the etching resistance layer 18 and the resistance layer protective film 19 has a small space 17a, the etching solution is etched by the large hole 14 side.
Even when 16a penetrates to the etching resistance layer 18, the etching pressure and the air pressure remaining in the space and the pressure of the etching resistance layer are well balanced, and the cross-sectional shape of the etching resistance layer 18 can be maintained. Great hole 14
The etching on the side can be sprayed with the etching liquid 16a from above and below, so that the wave of the thin metal plate 11 can be prevented, so that a more stable opening 20a of the shadow mask can be obtained. [Effects of the Invention] As is clear from the above description, according to the shadow mask manufacturing method of the present invention, after forming the resistive layer, the resistive layer protective film is attached to the surface of the resistive layer, whereby the metal thin plate is formed. An opening having a diameter smaller than the thickness and a uniform cross-sectional shape can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view showing an opening shape in an opening forming process according to one embodiment of the present invention, FIG. 2 is a schematic process diagram showing the opening forming step, FIG. FIG. 4 is a schematic cross-sectional view showing a shape of an opening in a process of forming an opening in a conventional method of manufacturing a shadow mask. FIG. 4 is a schematic view showing a process of forming the opening. FIG. It is a cross section schematic diagram showing a cross section. 11 Metal sheet 12 Resist layer 13 Small hole 14 Large hole 15 Organic synthetic protective film 17 Concave part 18 Etching resistive layer 19 Resistive layer protective film 20a Open shadow mask Hole

Claims (1)

(57) [Claims] A first etching step in which one surface of the metal sheet is etched through a resist layer in which a small opening is formed to form a large number of recesses on one surface of the metal sheet; and etching is performed by the first etching step. A resist layer removing step of removing a resist layer on one surface of the metal sheet subjected to the above, and applying a resistive material having etching resistance on the surface of the metal sheet from which the resist layer has been removed in the resist layer removing step A resistance layer forming step of forming a resistance layer by drying and drying, and a surface of the resistance layer formed in the resistance layer formation step is slightly depressed along the recess, and the resistance layer is formed between the depression and the resistance layer protection film. A protective film covering step of covering the surface of the resistive layer in a form having a space with a resistive layer protective film in close contact with an adhesive layer or an adhesive layer, A second etching step of etching the other surface through the resist layer in which the large opening is formed and penetrating to the concave portion, and a residue removing step of removing the remaining resistive layer protective film, resistive layer and resist layer. A method for manufacturing a shadow mask, comprising: 2. 2. The method according to claim 1, wherein a protective film is attached to the other surface before the first etching step, and the protective film is removed before the step of forming the resistance layer.
The method for producing a shadow mask according to any one of the preceding claims. 3. 2. The method according to claim 1, wherein the resistance layer protection film is made of at least one of polyethylene, polypropylene, polyvinyl chloride, and polyester.
3. The method for manufacturing a shadow mask according to item 2 or 2. 4. The resistance layer is made of paraffin, oil pitch, lacquer,
3. The method for producing a shadow mask according to claim 1, wherein said method comprises at least one of alkali milk caseinate, polyvinyl alcohol, epoxy dispersion resin and alkyd resin.