JPH0845422A - Manufacture of shadow mask - Google Patents

Abstract

PURPOSE:To manufacture a highly accurate shadow mask by forming a pre- stage coat layer on etched metal surface with a roll coater, and a post-stage coat layer on it with a photogravure coater to form an etching prevention layer. CONSTITUTION:A plate type shadow mask metallic material 1 with the prescribed pattern of a resist film formed on both sides, us passed through the first etching chamber 7, and subjected to an intermediate etching process. Then, an etching prevention layer formed out of a pre-stage coat applied with a roll coater 9 and a post-stage coat applied with a photogravure coater for filling a recess at a metal exposure section on one side, is formed on the metallic material 1. Thereafter, the material 1 is passed through the second etching chamber 11 via a drying and curing area 24. In this case, a recess at a metal exposure section on the other side is further etched, thereby forming a recess hole communicated to the recess on one side. Then, the etching prevention layer and the resist film are removed in a film separation chamber 12.

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 by a photoetching method, and more particularly to a method for producing a high-definition shadow mask having a small diameter of apertures and a large number of apertures.

[0002]

2. Description of the Related Art Conventionally, a shadow mask used for a color picture tube is manufactured by a process as shown in FIG. That is,
As the shadow mask material 1, for example, a low carbon steel plate having a thickness of 0.13 mm is used, and after degreasing, surface conditioning and cleaning treatment on both sides, casein or polyvinyl alcohol and ammonium dichromate are applied to the water-soluble photosensitive solution on both sides. After drying, the photoresist film 2 is formed. Next, one surface of the shadow mask material 1 is exposed with a negative pattern of a small hole image and the other surface is exposed with a negative pattern of a large hole image. After that, with warm water,
When the developing process for dissolving the unexposed uncured photoresist film is performed, as shown in FIG. 3A, the small hole resist film 2a is formed.
Shadow mask material 1 having a large hole resist film 2b on both sides
Is obtained.

After that, the resist film 2 is subjected to a hardening treatment and a burning treatment, and first-stage etching is performed from both front and back surfaces. The etching solution is a ferric chloride having a Baume concentration of 35 to 50, and spray etching is generally performed at a spray pressure of 1.5 to 3.5 kg / cm ² . In this first etching step, as shown in FIG. 3B, it is important to stop the etching progress on the way. Further, in this first etching step, there is also a method in which a protective film is attached to the surface of the shadow mask material 1 having the large hole resist film 2b and the shadow mask material 1 is etched halfway only from the small hole side.

Next, as shown in FIG. 3C, an etching prevention layer 4 is formed by coating so as to completely fill the recess 3b on the small hole side formed by the preceding etching. Then, FIG.
As shown in (d), the second etching step of etching the shadow mask material 1 only from the large hole side is performed to form the opening 5 penetrating from the large hole side to the small hole. Finally, the etching prevention layer 4 and the resist film 2 are peeled off, washed with water and dried to obtain a flat shadow mask 6 shown in FIG.

In this conventional method, it can be said that the side etching phenomenon, which cannot be avoided by the photoetching method, is suppressed on the small hole side. That is, by filling the recesses on the small hole side with the etching prevention layer and not side-etching the small holes in the second etching step, the accurate small hole pattern in the first etching step can be maintained. Therefore, for example, it is possible to open a hole having a hole diameter smaller than the thickness of the material metal plate.

However, this conventional method is not without problems. According to the conventional method, the etching prevention layer is formed by a spray coating method, but this method has the following drawbacks. Since a large number of spray nozzles are arranged, the coater becomes large. Maintenance of the coater is troublesome due to contamination by spray droplets and accumulation of coat liquid. Bubbles are easily trapped and remain in the etching prevention layer. In particular, the second drawback is that the remaining bubbles may promote the side etching phenomenon of the small holes in the second etching process, resulting in the enlargement of the shape of the openings or the failure of a predetermined circular shape. It was the cause of poor hole shape.

[0007]

In view of the above-mentioned circumstances, the present invention proposes a method for forming an etching preventive layer in which a bubble is not taken in and remains in a method for manufacturing a shadow mask. The present invention has been accomplished, and an object of the present invention is to provide a method for manufacturing a shadow mask in which the resulting shadow mask does not have defective openings.

[0008]

That is, according to the present invention, at least one surface of a plate-shaped shadow mask metal material having a resist film on which a metal surface is partially exposed according to a predetermined pattern is formed on both surfaces. Then, a first etching step of forming a concave portion on at least this one surface of the metal exposed portion, and an etching prevention layer is applied to one surface having the concave portion formed in the first etching step, and the concave portion is formed. Filling the inside with an etching prevention layer, and etching the surface opposite to the surface on which the etching prevention layer is provided, and forming a concave hole leading from this opposite surface to the concave portion formed on the one surface. In the method for producing a shadow mask, which comprises at least a second etching step and a film removing step for removing the etching prevention layer and the resist film, As the coating means ring preventing layer,
A method for producing a shadow mask, characterized by using a two-step coating method comprising a front coat of a roll coater and a rear coat of a gravure coater.

However, various modifications can be made to the embodiment of the method for manufacturing a shadow mask of the present invention. One of them is to replace the front coat of the roll coater with a gravure coater. In this case, two gravure coaters are lined up.

The next modification is that the gravure coater is a reverse gravure coater. "reverse"
Is the direction of rotation of the gravure roll in contact with the object to be coated,
It is a turning direction that is opposite to the traveling direction of the object to be coated. Hereinafter, unless otherwise specified, when simply referred to as “gravure coater”, it means a natural gravure coater in which the rotation direction of the gravure roll is the same as the traveling direction of the coated object, and is distinguished from the reverse gravure coater. To do.

The ink supply system of the gravure coater is preferably the ink circulation system regardless of whether it is reverse or natural. This is because the ink can always be supplied to the plate in a clean state by attaching a filter to the ink circulation path.

As a method for manufacturing a shadow mask to which the present invention can be applied, it goes without saying that the conventional technique described with reference to FIG. 3 can be applied. More generally speaking, the present invention can be applied to any method of manufacturing a shadow mask, which includes a step of dividing etching into two stages and filling an etching prevention layer into a recessed portion on one side of which halfway is etched. The recess for filling the etching prevention layer may be on the small hole side or the large hole side, but in many cases,
It is a small hole side.

[0013]

The present invention is a combination of a roll coater pre-coating and a gravure coater post-coating as means for applying the etching preventive layer in the shadow mask manufacturing process. The roll coater is good at supplying a sufficient amount of ink to the surface to be coated and pushing the ink into the etched recesses, and the gravure coater is able to push the ink into the etched recesses and evenly without pinholes. It is good to obtain a coating film of various thickness. The roll coater may be replaced with a gravure coater, but in any case, the present invention can fill the etching recess with the etching prevention layer without enclosing air bubbles.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to FIGS. In FIG. 1, a shadow mask material 1
Is a long metal plate supplied from a winding roll, for example, a low carbon steel having a plate thickness of 0.13 mm or a low expansion amber material is used. By performing the steps already described in the section (Prior Art), a shadow mask material 1 having a small hole resist film 2a and a large hole resist film 2b on the front and back sides as shown in FIG. 3A is obtained. .

Next, when the shadow mask material 1 is passed through the first etching chamber 7 shown in FIG. 1, the front and back of the shadow mask material 1 are partly etched by the etching liquid ejected from the spray nozzles 8 provided above and below, Recesses 3a and 3b are formed as shown in FIG. 3 (b).

The shadow mask material 1 which has passed through the first etching chamber 7 is conveyed upward and inverted so that the small hole side filled with the etching prevention layer is the lower surface. This is because in the case of coating with a cylinder roll, it is suitable that the coating surface is on the lower side. The shadow mask material 1 which has been turned over so that the small hole surface is on the lower side is subjected to a two-step coating method of a front coat of the roll coater 9 and a rear coat of the gravure coater 10. This is one of the features of the present invention.

This point will be described with reference to FIG. 2. The shadow mask material 1 conveyed from the right side is applied to the coating roll.
It is sandwiched between 13 and the pressure roll 16, and the supply liquid 14 supplies the coating liquid of the ink pan 15 to the surface of the coating roll 13 to spread the coating liquid on the small hole side of the lower surface of the shadow mask material 1. The role of the coating roll 13 is to supply a sufficient amount of ink to the surface to be coated and to push the ink into the etched recess. However, as a property of the roll coater, there is some insufficiency in pushing the ink into the etched concave portion and leveling the coating liquid to obtain a coating film having a uniform film thickness.

Next, a post-stage coating by the gravure coater 10 is performed. As with the previous stage, gravure roll 17 and impression cylinder 22
Although the shadow mask material 1 is passed between the two, the rotation direction of the gravure roll 17 is reverse in the illustrated embodiment. In the case of the reverse gravure roll 17, since the relative speed with the shadow mask material 1 is high and the contact is in the opposite direction, the action of pushing the coating liquid into the concave portion at the contact surface is strong. Moreover, since the gravure coater 10 is suitable for uniformly spreading the coating liquid, it does not cause coating defects such as pinholes.

The coating liquid of the gravure coater 10 is supplied in a circulating system. The tip 23 of the coating liquid supply device 18 slides on the surface of the reverse gravure roll 17 to scrape off excess coating liquid other than the coating liquid filled in the ink cells engraved on the surface of the gravure roll. Excess coating liquid
It is circulated from the ink receiver 19 through the pump 20 and the filter 21. The advantage of this method is that the coating solution is always clean through the filter.

There may be several variations on the embodiment shown in FIG. For example, the roll coater of the first coat is a roll coater of two or more rows and a plurality of rows. This makes it possible to sufficiently supply the coating liquid.
Alternatively, instead of the front coat of the roll coater, the front coat may also be a gravure coater. In this case, the thickness of the coating film can be made even more uniform.

The shadow mask material 1 on which the etching prevention layer has been applied is passed through the second drying / curing area 24 and then passed through the second etching chamber 11. The spray nozzle sprays the etching solution from the large hole side, that is, from below. In this way, a through hole communicating from the large hole side to the small hole is opened to obtain the state shown in FIG. 3D, and finally, the etching prevention layer and the resist film 2 are removed in the film peeling chamber 12,
The flat type shadow mask shown in (e) was obtained.

[0022]

As described above, according to the method for producing the shadow mask of the present invention, the roll coater is used as the method for applying the etching prevention layer, so that the roll coater applies a sufficient amount of ink to the surface to be coated. It is good at supplying and pushing the ink into the etched recess, and the gravure coater is good at pushing the ink into the etched recess and obtaining a coating film with a uniform film thickness without pinholes. There is.

Therefore, as compared with the spray method, bubbles are not taken into the etching prevention layer. Therefore, the remaining bubbles do not promote the side etching phenomenon of the small holes in the second-stage etching, and as a result, the shape of the openings is enlarged,
Poor shape defects such as not having a predetermined circular shape can be suppressed. . Since the coating method is the roll coater method, the coater is smaller than the spray method. Maintenance of the coater is easy because there is no contamination due to spray droplets and no coating liquid retention. That is, it has an excellent effect in practical use.

[0024]

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a shadow mask manufacturing method of the present invention.

FIG. 2 is an explanatory view showing a main part of an embodiment of a method for manufacturing a shadow mask of the present invention.

FIG. 3 is an explanatory view showing an example of a method of manufacturing a shadow mask in the order of steps.

[Explanation of symbols]

 1 Shadow Mask Material 2 Resist Film 3 Recess 4 Etching Prevention Layer 5 Opening 6 Shadow Mask 7 First Etching Chamber 8 Nozzle 9 Roll Heater 10 Gravure Coater 11 Second Etching Chamber 12 Stripping Chamber 13 Coating Roll 14 Supply Roll 15 Ink Pan 16 Pressure roll 17 Gravure roll 18 Coating liquid supply device 19 Ink receiver 20 Pump 21 Filter 22 Impression cylinder 23 Tip 24 Drying / curing area

Claims (5)

[Claims] 1. A metal on at least one of the surfaces of a plate-shaped shadow mask metal material having a resist film on which a metal surface is partially exposed according to a predetermined pattern is etched on at least one surface. A first etching step of forming a concave portion in the exposed portion; a step of applying an etching prevention layer on one surface having the concave portion formed in the first etching step and filling the inside of the concave portion with the etching prevention layer; A second etching step of etching a surface opposite to the surface on which the etching prevention layer is provided to form a concave hole communicating from the opposite surface to a concave portion formed on the one surface; In the method for producing a shadow mask, which comprises at least a layer and a stripping step of removing the resist film, a roll is used as the means for applying the etching prevention layer. A method for producing a shadow mask, which comprises using a two-step coating method comprising a coater pre-coating and a gravure coater post-coating. 2. The method for producing a shadow mask according to claim 1, wherein instead of the front coat of the roll coater, the front coat is also a gravure coater. 3. The method for producing a shadow mask according to claim 1, wherein the roll coater of the pre-coat comprises a plurality of rows of roll coaters of two or more lines. 4. The method of manufacturing a shadow mask according to claim 1, wherein the gravure coater is a reverse gravure coater. 5. The method for producing a shadow mask according to claim 1, 2, 3 or 4, wherein the coating solution supply system of the gravure coater is a coating solution circulation system.