JPH0430133B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a method for manufacturing a shadow mask used in a color cathode ray tube.

[Technical background of the invention and its problems]

Color cathode ray tubes are used for general home use, monitors,
They are used for a wide variety of purposes, such as displays loaded on aircraft, and apart from those for general home use, monitors and displays require extremely fine image quality, so they are installed on these color cathode ray tubes. The electron beam passage hole of the shadow mask is required to be highly precise and minute.

To explain the shape of the electron beam passage hole of such a shadow mask, as shown in FIG. 1, a rectangular electron beam passage hole 3 is continuous in the longitudinal direction of the shadow mask material 1 with a bridge 2 interposed therebetween. Each of the rectangular electron beam passing holes 3 is formed in such a shape that the surface on which the electron beam 4 enters is a small hole 3 ₁ and the surface facing the phosphor screen is a large hole 3 ₂ . In order to prevent the reflection of the electron beam 4 on the inner surface of the hole 31, the small hole ₃₁ is formed into a substantially knife-edge shape with a depth t very small relative to the material plate thickness T. As another example, as shown in FIG. 2, a circular electron beam passage hole 13 provided at each vertex of a triangle is formed in a shadow mask material 11, and the surface on which the electron beam 14 is incident is a small hole 13 ₁ and a phosphor screen. The side surface is formed in a shape with a large hole 13 ₂ , and in order to prevent reflection of the electron beam 14 on the inner surface of the circular electron beam passage hole 13 , the small side hole 13 is formed with respect to the material plate thickness T. It is formed almost in the shape of a knife edge with a _very small depth t. Such an electron beam passage hole is formed by etching, but the molded flat mask needs to have appropriate mechanical strength when it is pressed into a shadow mask or when it is attached to a color cathode ray tube.

As mentioned above, it is advantageous when the thickness of the shadow mask material, such as iron, is thin in order to create minute and highly accurate electron beam passage holes by etching, but thin plates have problems in terms of mechanical strength. Inferior. Therefore, the plate thickness must be increased so that a certain degree of mechanical strength is satisfied. However, when attempting to drill fine and highly accurate holes in a thick shadow mask material, the etching time becomes long, and as a result, the dimensions and shape are likely to be distorted due to etching, resulting in a lack of etching stability.

That is, an etching method in which etching is performed from both principal surfaces may result in excessive etching or irregular etching. Further, as the shadow mask material is etched vertically, etching progresses in the lateral direction, so it is difficult to form fine electron beam passage holes by etching from both main surfaces. Furthermore, when this method of etching from both principal surfaces is continuously applied to a band-shaped shadow mask material, it becomes even more difficult to form fine electron beam passage holes.

As a method to solve the problems of the method of etching from both main surfaces, it is called the single-side etching method, and the etching is divided into two stages. Afterwards, you can temporarily cover the etched surface with varnish or a microwave, and in the latter half of the etching process, etch it from the back side to form the electron beam passage hole, or you can use Mylar base or polyprofil. There are methods such as etching while partially shielding, but all of these methods have the problem that they are complicated and time-consuming, and are not suitable for mass production.

As a method for improving this single-sided etching, the present inventors previously proposed the following method for manufacturing a shadow mask.

First, a photoresist film is applied and formed on both main surfaces of a long shadow mask material, and patterns corresponding to the predetermined micropores shown in FIGS. 1 and 2 are placed at regular intervals to correspond to one shadow mask. That is, a small hole forming part and a large hole forming part are formed by a light exposure method so that the opening sizes on both main surfaces are different when etching is completed. Next, one side of the shadow mask, for example, the small side hole 3 ₁ on the electron gun side in FIG.
Press the organic film onto the corresponding surface using adhesive. Acrylic resin is used as the adhesive,
A 0.1 mm polyethylene film is used as the organic film.

As shown in FIG. 3, this organic film is bonded by applying an adhesive to an organic film 15 having a width corresponding to the shadow mask material 21 to be applied, covering it with a release paper 16, and placing it on a rolled drum. Supplied from. The organic film 15 is attached to the roller 17
The release paper 16 is simultaneously separated by the roller 18 while applying tension. Next, the organic film 15 is pressed and pressed by rollers 19 and 20 so that the adhesive-applied surface is in contact with the shadow mask material 21. The pressing force at this time is approximately 2
Kg/ ^cm2 , the adhesive strength of organic film 15 is 200-400
(g/25mm width) is preferred.

However, with such adhesive strength, organic film 15
By pressing the adhesive onto the shadow mask material 21, it is possible to prevent the corrosive liquid from penetrating between the organic film 15 and the shadow mask material 21. It was found that this adhesive tends to remain in the hole formation area, and this adhesive interferes with the formation of the hole during the corrosion process, ultimately causing clogging or poor hole diameter in the electron beam passage hole. .

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a method for manufacturing a shadow mask that can form high-definition electron beam passage holes in a shadow mask material using a single-sided etching method.

[Summary of the invention]

That is, the present invention involves a step of leaving a photoresist film on both main surfaces of a long shadow mask material, excluding the large hole and small hole formation portions, and a step of leaving a photoresist film on both main surfaces of a long shadow mask material, and removing a photoresist film near both ends in the width direction of one of the main surfaces of the shadow mask material. A process of crimping an etching liquid-resistant film that covers this one main surface with an adhesive outside the surface, and etching through the large hole or small hole forming part of the other main surface of the shadow mask material. A first etching step of forming a first hole, a step of filling a shielding agent of an etching solution into the first hole, a step of peeling off the film, and a step of forming a large hole or a large hole from one main surface of the shadow mask material. A second etching step in which the shielding agent is exposed through the small hole forming portion and a second hole is formed until an electron beam passing hole with a desired diameter is formed; and a step in which the shielding agent and the photoresist film are removed. A method for manufacturing a shadow mask, comprising:

[Embodiments of the invention]

Next, one embodiment of the present invention will be described with reference to FIGS. 4 to 9.

First, before etching, both main surfaces of the long shadow mask material, such as a metal plate mainly composed of iron or an amber plate, are cleaned, and then a photosensitive liquid mainly composed of milk casein,
That is, about 1% by weight of ammonium dichromate is added as a brightening agent to milk casein, and the specific gravity is
A photosensitive solution adjusted to 1.028 was applied by vertical pulling method using the dip method.
Dry for a minute to form a photoresist film on both main surfaces.

Next, in an exposure step, a negative original plate consisting of a negative pattern for small holes and a negative pattern for large holes is placed on the photoresist film on both main surfaces in close contact with each other and exposed to light using a mercury lamp. Next, develop with warm pure water at about 40℃ and then at 150℃.
By _drying in _an atmosphere of A shadow mask member 31 in which the photoresist films 32 and 33 remain is formed.

Next, as shown in FIGS. 8 and 9, a shadow mask member 3 in which, for example, a small hole forming part 34 is formed.
An adhesive 36 made of acrylic resin or the like is used at both ends of the shadow mask member 31 in the width direction to cover one main surface of the shadow mask member 31 on which the small hole forming part 34 is formed. A film 37 having the following properties is crimped.

This pressure bonding method is the same as that shown in FIG. 3, so it is not particularly shown, but the film 37 is supplied from a drum in which an adhesive 36 is applied in advance to a film having a width corresponding to the shadow mask material, the film is covered with a release paper, and is wound into a roll. At the same time, while applying tension with a roller, the release paper is separated using another roller, and then the film 37 is pressed and bonded with pressure using a roller so that the surface coated with the adhesive 36 is in contact with one main surface of the shadow mask member 31. do. The pressure at this time is approximately 2Kg/cm ² and the adhesive strength of the film 37 is 200 to 400.
(g/25cm width) is preferable. in this case,
Care must be taken to ensure that the adhesive 36 does not enter the effective surface area that will form the flat mask indicated by the dashed line 38.

Next, as shown in FIG. 5, a large hole 39 is formed to a predetermined depth as a predetermined first hole portion by spray etching from the large hole forming portion 35 side.

After washing with water and drying with hot air,
As shown in FIG. 6, at least the large hole 39 is filled with a shielding agent 40 of an etching solution such as paraffin.

Next, the film 37 is peeled off, and the shielding agent 40 is exposed by spray etching from the small hole forming part 34 side, and small holes 41 as second holes are formed until an electron beam passing hole with a desired diameter is formed. do.

Next, as shown in FIG. 7, the shielding agent 40 is removed,
Electron beam passage hole 4 consisting of a small hole 41 having an opening with a diameter D ₁ and a large hole 39 having an opening with a diameter D ₂
Get 2.

Next, the photoresist films 32 and 33 are removed to complete the flat mask.

In the embodiment described above, the film was provided on the side of the shadow mask member where the small hole forming portion is located, but it may be provided on the side of the shadow mask member where the large hole forming portion is located.
It goes without saying that the small hole and large hole forming portions may be rectangular instead of circular.

〔Effect of the invention〕

As described above, according to the present invention, etching of one main surface is prevented by a film in the single-sided etching method, and the film is crimped to the shadow mask member using an adhesive outside the effective area that will become the flat mask. When the film is peeled off, the film does not remain in the flat mask formation area, especially in the small hole and large hole formation areas, and it is possible to obtain a shadow mask of extremely high quality, which is of great industrial value.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a state in which a rectangular hole is bored in the shadow mask material. Fig. 3 is a diagram showing a state in which a shaped hole is drilled, Fig. a is a plan view, Fig. b is a sectional view taken along line B-B' in Fig. a, and Fig. 3 is a film crimping used in one step of the earlier application. Schematic diagrams showing the device, Figures 4 to 9
4 is a cross-sectional view showing a state in which the photoresist film remains on both main surfaces of the shadow mask material except for the small hole and large hole forming portions; FIG. The figure is a cross-sectional view showing a state in which a film is provided on the side where the small hole is formed in the shadow mask member, and the first hole is drilled from the side where the large hole is formed. A cross-sectional view showing a state in which the shielding agent is filled, the film is removed, and a second hole is drilled from the small hole forming part side, FIG. 7 is a cross-sectional view showing a state in which the shielding agent is removed, and FIG. FIG. 9 is an enlarged view of section A in FIG. 8, which is a perspective view showing a state in which the film is pressed onto the small hole forming portion side of the shadow mask member through an adhesive. 1, 11, 31...Shadow mask material, 3,
13, 42...electron beam passage hole, 15, 37
...Film, 32, 33...Photosensitive film, 34...
Small hole forming part, 35... Large hole forming part, 36... Adhesive, 39... First hole part, 40... Shielding agent, 41
...Second hole.

Claims (1)

[Claims] 1. A step of leaving a photoresist film on both main surfaces of a long shadow mask material, excluding the large hole and small hole forming portions, respectively, and a step of leaving a photoresist film on both main surfaces of a long shadow mask material, and leaving a photoresist film outside the effective surface near both ends in the width direction of one of the main surfaces of the shadow mask material. A step of press-bonding an etching liquid-resistant film covering one main surface of the shadow mask material with an adhesive, and etching the first film through the large hole or small hole forming portion of the other main surface of the shadow mask material. a first etching step of forming a hole, a step of filling the first hole with a shielding agent of an etching solution, a step of peeling off the film, and a step of etching the large hole from one main surface of the shadow mask material. or a second etching step in which the shielding agent is exposed through the small hole forming part and a second hole is formed until an electron beam passing hole having a desired diameter is formed; and the shielding agent and the photoresist film are removed. A method for producing a shadow mask, comprising the step of removing.