JP3063530B2 - Manufacturing method of shadow mask - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a shadow mask by a photoetching method, and more particularly to a method of manufacturing a high-definition shadow mask having a small number of openings and a large number of openings.

[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,
For example, a low carbon steel sheet having a thickness of 0.13 mm is used as the shadow mask material 1, and both sides are degreased, leveled, and cleaned, and then coated with a water-soluble photosensitive solution composed of casein, polyvinyl alcohol, and ammonium bichromate on both sides. After drying, a photoresist film 2 is formed. Next, one side of the shadow mask material 1 is exposed to the negative pattern of the small hole image, and the other side is exposed to the negative pattern of the large hole image. Then, with warm water,
If a developing process for dissolving the unexposed and uncured photoresist film is performed, as shown in FIG.
Mask material 1 which has a resist film 2b on both sides
Is obtained.

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

Next, as shown in FIG. 3C, an etching prevention layer 4 that completely fills the small-hole-side recess 3b formed by the preceding etching is applied and formed. Subsequently, FIG.
As shown in (d), a second etching step of etching the shadow mask material 1 only from the large hole side is performed, and an opening 5 penetrating from the large hole side to the small hole is formed. Finally, the etching prevention layer 4 and the resist film 2 are peeled off, washed with water and dried to obtain a flat type 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 photo etching method is suppressed on the small hole side. That is, the concave portion on the small hole side is filled with the etching prevention layer, and the small hole is not side-etched in the second etching step, so that a precise small hole pattern in the first etching step can be maintained. Therefore, for example, it is possible to form a hole having a hole diameter smaller than the thickness of the material metal plate.

However, this conventional method is not without its problems. According to the conventional method, the formation of the etching prevention layer is performed by a spray coating method, but this method has the following disadvantages. Since a large number of spray nozzles are arranged, the coater becomes large. Maintenance and management of the coating device is troublesome due to contamination due to spray droplets and retention of the coating liquid. Bubbles are easily taken in and left in the etching prevention layer. In particular, the second disadvantage is that the remaining air bubbles may promote the side etching phenomenon of the small holes in the second etching step, and as a result, the shape of the opening may not be enlarged or a predetermined circular shape may not be obtained. Caused the hole shape to be poor.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and in a method of manufacturing a shadow mask, a method of forming an etching prevention layer in which air bubbles are not captured and remains does not exist. It is an object of the present invention to provide a method of manufacturing a shadow mask in which an opening of a defective shape does not occur in the obtained shadow mask.

[0008]

That is, according to the present invention, at least one surface of a plate-shaped shadow mask metal material on which a resist film partially exposing a metal surface is formed in accordance with a predetermined pattern on both surfaces. A first etching step of forming a recess in at least one of the metal exposed portions of the surface, and applying an etching prevention layer to one surface having the recess formed in the first etching step, A step of filling the inside with an etching prevention layer, and etching a surface opposite to the surface provided with the etching prevention layer to form a concave hole from the opposite surface to the concave portion formed on the one surface. A method of manufacturing a shadow mask, the method comprising at least a second etching step for removing the etching prevention layer and a resist film. As the coating means ring preventing layer,
A shadow mask manufacturing method characterized by using a two-stage coating method of a former coat of a roll coater and a later coat of a gravure coater.

However, there may be various modifications in the embodiment of the shadow mask manufacturing method of the present invention. One of them is to use a gravure coater for the former coat instead of the former coat for the roll coater. In this case, two gravure coaters are arranged.

[0010] A second modification is that the gravure coater is a reverse gravure coater. "reverse"
Means that the rotation direction of the gravure roll in contact with the coating object is
It refers to the direction in which the direction of movement of the object is reversed. Hereinafter, unless otherwise specified, simply referred to as `` gravure coater '' means a natural gravure coater in which the direction of rotation of the gravure roll is the same as the traveling direction of the object to be coated, and is distinguished from a reverse gravure coater. I do.

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

As a method of 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 including a step of dividing the etching into two stages and filling a concave portion etched halfway on one side with an etching prevention layer. The concave portion 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]

According to the present invention, in the manufacturing process of the shadow mask, as a means for applying the etching preventing layer, a former coat of a roll coater and a latter coat of a gravure coater are combined. A roll coater is good at supplying a sufficient amount of ink to the surface to be coated and pushing ink into etched recesses, while a gravure coater is capable of pushing ink into etched recesses and has no pinholes. It is good at obtaining a coating film having a large thickness. The roll coater can be replaced with a gravure coater, but in any case, the present invention can fill the etched recess with an etching prevention layer without embracing bubbles.

[0014]

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

Next, if the shadow mask material 1 is passed through the first etching chamber 7 of FIG. 1, the front and back surfaces of the shadow mask material 1 are etched halfway by an etching solution blown out from spray nozzles 8 provided above and below. Concave portions 3a and 3b are formed as shown in FIG.

The shadow mask material 1 that has passed through the first etching chamber 7 is transported upward, and is turned upside down such that the side of the small hole filled with the etching prevention layer faces downward. This is because, in the application by the cylinder roll, it is suitable that the application surface is on the lower side. The two-stage coating method of the former coat of the roll coater 9 and the latter coat of the gravure coater 10 is performed on the shadow mask material 1 with the small hole surface facing downward. 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 is applied to a coating roll.
The application liquid of the ink pan 15 is supplied to the surface of the application roll 13 by the supply roll 14, so that the application liquid is developed 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 properties of the roll coater, there are some inadequacies in pushing the ink into the etched concave portions and in obtaining a coating film having a uniform film thickness by leveling the coating liquid.

Next, a second coat is performed by the gravure coater 10. As before, the gravure roll 17 and impression cylinder 22
In the illustrated embodiment, the rotation direction of the gravure roll 17 is reversed. In the case of the reverse gravure roll 17, since the relative speed to the shadow mask material 1 is high and the contact is made in the opposite direction, the function of pushing the coating liquid into the concave portion on the contact surface is strong. In addition, since the gravure coater 10 is suitable for uniformly spreading the coating liquid, it does not cause coating defects such as pinholes.

The coating solution of the gravure coater 10 is supplied in a circulation system. The tip portion 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
The ink 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 are several possible variations on the embodiment shown in FIG. For example, the roll coater of the former coat is a roll coater of two or more rows. In this case, the supply of the coating liquid can be made sufficient.
Alternatively, instead of the former coat of the roll coater, the former coat can also be a gravure coater. In this case, the thickness of the coating film can be made more uniform.

The shadow mask material 1 on which the application of the etching prevention layer has been completed passes through the second etching chamber 11 through the drying / curing area 24 on the upper side. The spray nozzle sprays the etching liquid from the large hole side, that is, from below. In this way, a through hole is opened from the large hole side to the small hole, and the state shown in FIG. 3D is obtained. Finally, the etching prevention layer and the resist film 2 are removed in the stripping chamber 12 to obtain the state shown in FIG.
A flat type shadow mask shown in (e) was obtained.

[0022]

As described above, according to the method of manufacturing a shadow mask of the present invention, a roll coat method is employed as a method of applying an etching prevention layer, so that a roll coater applies a sufficient amount of ink to a surface to be coated. The gravure coater is good at supplying ink and pushing ink into etched recesses, and is good at pushing ink into etched recesses and obtaining a coating film with a uniform thickness without pinholes. I have.

Therefore, bubbles are not taken into the etching prevention layer as compared with the spray method. 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 opening increases,
Poor hole shape, such as not being a predetermined circle, can be suppressed. . Since the coating method is a roll coater method, the coating apparatus is smaller than a spray method. There is no contamination due to spray droplets or stagnation of the coating liquid, and maintenance of the coating apparatus is easy. That is an effect that is excellent in practical use.

[0024]

[Brief description of the drawings]

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

FIG. 2 is an explanatory view showing a main part of one embodiment of a method of 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]

 REFERENCE SIGNS LIST 1 shadow mask material 2 resist film 3 concave portion 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)

(57) [Claims] At least one surface of a plate-shaped shadow mask metal material on which a resist film partially exposing a metal surface is formed in accordance with a predetermined pattern on both surfaces is etched, and at least one surface of the metal is removed. A first etching step of forming a concave portion in an exposed portion, and a step of applying an etching preventing layer to one surface having the concave portion formed in the first etching step, and filling the inside of the concave portion with the etching preventing layer; A second etching step of etching a surface opposite to the surface provided with the etching prevention layer, and forming a recess from the opposite surface to a recess formed in the one surface; and A method of manufacturing a shadow mask having at least a film removing step of removing a layer and a resist film, wherein a roll is used as a means for applying the etching prevention layer. A method for producing a shadow mask, comprising using a two-step coating method including a coat at a former stage of a coater and a coat at a latter stage of a gravure coater. 2. The method according to claim 1, wherein the first coat is a gravure coater instead of the first coat of the roll coater. 3. The method of manufacturing a shadow mask according to claim 1, wherein the roll coater of the first coat comprises a plurality of rows of roll coaters of two or more. 4. The method according to claim 1, wherein the gravure coater is a reverse gravure coater. 5. The method of manufacturing a shadow mask according to claim 1, wherein the gravure coater has a coating liquid supply system of a coating liquid circulation system.