KR19980051545A - Shadow mask of flat CRT - Google Patents

Abstract

The present invention relates to a shadow mask structure of a flat brown tube, and in particular, to increase the deformation force applied during stretching of the mask to distribute the stress concentration in a specific area, which is a problem that follows, so that the force for deformation to the front is evenly distributed and finally stress The purpose is to provide a savings mask.

In order to realize this, the present invention, the through hole is formed in the effective surface, which is the center portion of the mask so that the electron beam can be landing, the rail is fixed at a predetermined interval around the effective surface, the outer surface of the rail fixing portion In the shadow mask structure which consists of an invalid surface which is not influenced by an electron beam, it is comprised by half-etching the said invalid surface.

Description

Shadow mask of flat CRT

The present invention relates to a planar color brown tube, and more particularly, to a shadow mask structure for reducing stress concentrated in a mask during stretching of a shadow mask mounted inside the CRT.

Looking at the structure of a conventional shadow mask for a flat brown tube, as shown in FIG. 1, an effective surface portion 10 having a passage hole 7 formed therein for landing an electron beam, and an invalid surface portion 11 and 12 which are not affected by the electron beam. And 13 indicates the position where the rail is attached.

The shadow mask having such a structure is attached to the rail and then the ineffective surface 12 is cut to complete the mounting of the CRT.

When the CRT is activated, the electron beam emitted from the electron gun passes through the electron beam passing hole (7) of the shadow mask. At this time, the electron beam passing through is only about 20% of the total electron beam and the rest collides with the shadow mask to convert into heat. This heat causes a dominant phenomenon in which the shadow mask thermally expands.

This doming phenomenon changes the position of the electron beam landing on the fluorescent film, which lowers the color purity. To solve this problem, conventionally, an INVAR mask having a low thermal expansion or a bimetal is applied to a spring that fixes the shadow mask to the panel. Although it uses a method of suppressing ming, it raises the manufacturing cost of a product and reduces workability.

Therefore, recently, a flat foil tension mask (hereinafter referred to as a tension mask) is used to improve sharpness, which is caused by the collision of electron masks because the tension mask is forcibly tensioned to apply a tensile force to the mask. Since the thermal expansion of the mask is coped with the mechanical tension applied forcibly, the position of the hole formed in the mask does not change even at a high temperature.

Since the tension mask was a dot in the form of electron beam through-holes, the elastic modulus in the horizontal and vertical directions was similar, so that the effective surface could be uniformly applied and a lot of tension was applied. To this end, it is changed to a slot mask form, which is a trend these days, and the Young's modulus in the horizontal direction and the vertical direction is severely different, so that the effective surface cannot be applied uniformly and a lot of tension. In addition, if a small amount of deformation force is applied, mis-landing of electrons may occur due to the increase of the mask, and if a large amount of deformation force is applied, stress may be concentrated on a specific part of the mask, resulting in plastic deformation or breakage. Occurred.

In order to solve this problem, a method of forming a hole in the outer circumference of the mask effective surface was adopted. As shown in FIG. 2, the elastic force acted in both directions by forming the hole 30 in the A portion of the ineffective surface, When a large amount of deformation force is applied, a lot of stress is concentrated in the hole 30, thereby deforming the shape of the hole.

The present invention is formed by half-etching the tension mask non-effective surface to solve this problem, by increasing the tensile force applied to the mask to distribute the stress concentration of the specific area which is a problem that is followed by evenly distributed force for stretching to the front Finally, the aim is to provide a stress reduction mask.

1 is a structural diagram of a typical shadow mask.

Figure 2 is an embodiment of a conventional shadow mask.

3 is a structural diagram of a shadow mask of the present invention.

4 is an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

100, 200: effective surface portion 101: electron beam through hole

102: effective surface extension 103, 203: rail fixing

104, 204: half etching part

The present invention will be described in detail below with reference to the accompanying drawings.

Referring to the structure of the tension mask, as shown in FIG. 3, a through hole 101 is formed in the effective surface 100, which is the center portion of the mask, so that an electron beam can be landed, and a predetermined interval is formed in the peripheral portion of the effective surface 100. In the shadow mask structure in which the rail 103 is fixed and the outer surface of the rail fixing part 103 is formed of an invalid surface 104 which is not affected by the electron beam, the invalid surface 104 is placed on the half. Called to form.

And the effective surface extension 102 between the rail fixing part 103 and the effective surface 100 was also configured by half etching.

An important part of the process in the manufacture of CRT using the flat foil tension mask as a component is to force the mask by stretching and forcing it to a rail (frame). To do this, we first bit the edge of the mask with a gripper and stretch the mask to the plane using the power of the motor.

In this case, the shadow mask of the present invention forms an ineffective surface 104 half-etched on the outer circumference of the mask except the corner portion B of the mask, and the effective surface extension 102 also performs half etching. By doing so, the uniformity of elastic modulus can be improved and deformation can be stably executed. In other words, by improving the uniformity of the stress, it is possible to remove the stress concentration on the passage hole side 101 and to apply many deformations.

In another embodiment, the stress concentration of the corner portion can be eliminated by forming the ineffective surface half etching portion as shown in FIG. 4.

As described above, the present invention increases the strain applied to the flat foil tension mask, thereby dispersing the stress concentration at a specific portion so that the force for deformation is uniformly distributed to the front surface, thereby finally eliminating the mislanding of the electron beam. The savings mask can be provided.

Claims (3)

A through hole is formed in the effective surface, which is the central portion of the mask, so that the electron beam can be landed, and the rail is fixed at a predetermined distance to the periphery of the effective surface, and the outer surface of the rail fixing portion is ineffective without being affected by the electron beam. A shadow mask structure for a flat brown tube, characterized by comprising half-etching the ineffective surface in a shadow mask structure consisting of a face. 2. The shadow mask for a flat brown tube according to claim 1, wherein the shadow mask is formed by half-etching a portion of the ineffective surface except for the mask corner portion. 2. The shadow mask for flat brown tube according to claim 1, wherein the shadow mask is formed by half etching between the effective surface and the rail fixing part.