JPH0562591A - Shadow mask forming metal mold for cathode-ray tube - Google Patents

Abstract

PURPOSE:To provide a shadow mask forming metal mold for a cathode-ray tube capable of forming precise surface irregularities in a short time as well as capable of performing good polishing. CONSTITUTION:A punch is nearly box-shaped, a convex-shaped principal plane is formed on its front surface, a rectangular-shaped recessed part is formed on the principal plane, an irregularity forming part 16 is arranged on the recessed part in such a manner that irregularities are formed on the principal plane of a flat mask. A honeycomb-like etching surface 17 is formed on the irregularity forming part 16 in a recessed shape by etching, a polishing surface 18 is formed in a frame shape around the etching surface 17. The etching surface 17 and the polishing surface 18 on the irregularity forming part 16 of the punch is pressurized onto the flat mask so as to form mosaic irregularities.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube shadow mask molding die for forming a mosaic shape on the main surface of a cathode ray tube shadow mask.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a cathode ray tube shadow mask molding die for forming a mosaic pattern on the main surface of a cathode ray tube shadow mask is provided with a punch 1 having a curved front end surface. Blank holder 2 on both sides
And a die 3 is provided so as to face the blank holder 2, and a knockout 4 that faces the punch 1 and can move back and forth as the punch 1 moves back and forth is formed between the dies 3.

Then, a flat plate-shaped flat mask, which serves as a shadow mask for a cathode ray tube, is set on the die 3, and after being held by the blank holder 2, the punch 1 is advanced and the flat mask is placed between the punch 1 and the knockout 4. Hold it and perform overhanging. After this overhanging process, a gap is created between the die 3 and the blank holder 2, the punch 1 is advanced, and the knockout 4 is retracted while holding the main surface portion with the punch 1 and the knockout 4 to perform the drawing process. After the processing is completed, the knockout 4 is advanced to push up the shadow mask from the die 3 and take it out.

The shadow mask has a radius of 1000 to 2
Since it is formed in a curved surface of about 000 mm and the material thickness is thin, the strength of the curved surface forming the main surface of the shadow mask is low.

When this shadow mask is assembled in a cathode ray tube and is vibrated, the shadow mask is shaken inside the cathode ray tube and the screen is affected.

On the other hand, as a measure against the insufficient strength of the main surface portion of the shadow mask, there is a method of forming a bead or a fold of the main surface portion in a mosaic shape.

[0007]

However, it is necessary to make the surface of the punch 1 uneven in order to perform beading or folding of the principal surface portion in a mosaic shape. When the punch 1 is drawn, it is necessary to hold down the main surface of the flat mask, which becomes the shadow mask, together with the knockout 4, and to polish the surface from the viewpoint of material processing flow. is there.

On the other hand, when the unevenness is machined,
In order to prevent the generation of metal scraps and the generation of electric discharge in the pipe, a polishing process is required in the post-process of the unevenness, and the processing time becomes enormous. In addition, there is a problem that it is difficult to maintain accuracy because polishing is performed on a complicated shape with unevenness.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a shadow mask molding die for a cathode ray tube, which can form irregularities with high precision in a short time and can perform good polishing. To aim.

[0010]

According to the present invention, in a shadow mask molding die for a cathode ray tube for forming a mosaic shape on the main surface portion of a shadow mask for a cathode ray tube, the etching for forming the surface for forming the mosaic shape is performed. It is a face.

[0011]

According to the present invention, the surface for forming the mosaic shape is an etching surface formed by etching, so that unevenness is accurately generated, and the main surface portion of the shadow mask of the cathode ray tube is mosaic-shaped with this shadow mask molding die. By carrying out the molding, the main surface portion of the shadow mask is formed with high precision and good unevenness.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a shadow mask molding die for a cathode ray tube according to the present invention will be described below with reference to the drawings.

As shown in FIGS. 2 and 3, the punch 1 has a substantially box-shaped front surface on which a convex curved surface 11 serving as the main surface of the shadow mask is formed, and a rectangular concave portion 12 is formed on the curved surface 11. A frame-shaped contact surface 13 with the molding die is formed on the peripheral surface of the recess 12.

A communication hole 14 communicating with the back side is formed in the recess 12, and a spacer 15 is inserted from the communication hole 14. The communication hole 14 is normally closed by a cap (not shown) or the like.

Further, in the concave portion 12, a concave-convex forming portion 16 having substantially the same shape as the concave portion 12 and for forming concave-convex on a curved surface of a flat mask which is a shadow mask of a cathode ray tube, is formed by a spacer.
It is arranged on the surface side of 15. And this unevenness forming part
A mosaic-shaped etching surface 17 such as a honeycomb is formed in a concave shape on the 16 by etching, and a frame-shaped surface brushing surface 18 around the etching surface 17 is formed. Further, by inserting and removing the spacer 15 from the communication hole 14, the heights of the front surface of the unevenness forming portion 16 and the contact surface 13 are adjusted.

Then, as shown in FIG. 4, the punch 1 is arranged between the blank holders 2 and 2. A die 3 is provided so as to face the blank holder 2, and a knockout 4 that faces the punch 1 and that can move back and forth as the punch 1 moves back and forth is formed between the dies 3.

Next, the operation of the above embodiment will be described.

First, a flat plate-shaped flat mask, which is a shadow mask for a cathode ray tube, is set on the die 3 and is held by the blank holder 2, and then the punch 1 is advanced to make the punch 1
And a flat mask between the knockout 4 and
Perform overhang processing. After the overhanging process is completed, a gap is formed between the die 3 and the blank holder 2, the punch 1 is moved forward, and the knockout 4 is retracted while pressing the main surface portion with the punch 1 and the knockout 4, thereby performing the drawing process and punching. The etching surface 17 and the polishing surface 18 of the first unevenness forming portion 16 are pressed against a flat mask to form a mosaic unevenness. After the processing is completed, the knockout 4 is advanced to push up the shadow mask from the die 3 and take it out.

By pressing the shadow mask against the concave-convex forming portion 16 of the punch 1 in this way, the concave-convex shape of the honeycomb can be transferred to the front surface of the shadow mask, and the strength of the shadow mask of a particularly large CRT can be increased by the concave-convex shape. improves.

[0020]

According to the shadow mask molding die for a cathode ray tube of the present invention, unevenness is accurately generated by forming the mosaic surface as an etching surface formed by etching, and this shadow mask molding die is formed. By forming a mosaic shape on the main surface portion of the shadow mask of the cathode ray tube, it is possible to form the unevenness on the main surface portion of the shadow mask with good precision and good polishing.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an enlarged vicinity of a surface of an embodiment of a shadow mask molding die for a cathode ray tube according to the present invention.

FIG. 2 is a perspective view showing the same punch.

FIG. 3 is a sectional view of the same.

FIG. 4 is a cross-sectional view showing the entire shadow mask molding die of the same cathode ray tube.

[Explanation of symbols]

 17 Etched surface

Claims (1)

[Claims] 1. A shadow mask molding die for a cathode ray tube for forming a mosaic shape on a main surface of a shadow mask for a cathode ray tube, wherein the surface for forming the mosaic shape is an etching surface formed by etching. Mold for shadow mask of cathode ray tube.