KR100258914B1 - Shadow mask assembly having rollers for crt - Google Patents

Abstract

PURPOSE: A shadow mask assembly body for cathode ray tube equipped with roller is provided to prevent doming phenomenon of shadow mask by adopting frame equipped with roller to be able to absorb lateral expansion of shadow mask. CONSTITUTION: An electron beam pass hole(31a) is formed at shadow mask(31). Rollers(32)(33) is fixed at the edge of both end of above shadow mask(31). Frame supports rollers(32)(33) to be able to rotate. Expansion is absorbed by rotation of rollers when shadow mask(31) is made a thermal expansion in a lateral direction. The edge of both end of shadow mask(31) is welded at above rollers(32)(33). Rotation protrusion(32a)(33a) is formed at both end of rollers, combination hole that rotation protrusion is combined with is formed at frame.

Description

Shadow mask assembly for cathode ray tube with roller

The present invention relates to a cathode ray tube, and more particularly to a shadow mask assembly for a cathode ray tube comprising a shadow mask and a frame supporting the same.

Conventional color cathode ray tubes (CRTs) include shadow masks that selectively pass electron beams to produce color images.

Referring to FIG. 1, which illustrates a structure of a conventional cathode ray, a shadow mask assembly 20 is installed at a predetermined interval from a panel 11 coated with red (R), green (G), and blue (B) phosphors. It is. The shadow mask assembly 20 includes a shadow mask 21 having a plurality of electron beam through holes (not shown). The edge of the shadow mask 21 is welded to the frame 13 to be supported.

In the operation of a conventional cathode ray tube, an electron beam emitted from an electron gun (not shown) of a triode structure is deflected by a deflection yoke (not shown) according to an image signal and then passed through an electron beam passing hole of the shadow mask 21. It then collides with the phosphor and excites it to emit light.

Therefore, the distance between the shadow mask 21 and the panel 11 is adjusted so that the electron beam passing through the electron beam passing hole is accurately landed on the fluorescent film 11a.

However, part of the electron beam emitted from the electron gun collides with the shadow mask 21 to cause thermal expansion of the shadow mask 21. This thermal expansion, which occurs early in the operation of the cathode ray tube, causes the shadow mask 21 to be stressed in the transverse direction as shown by the arrow shown in FIG. 1. However, since the heat transfer to the frame 13 welded to and supporting the shadow mask 21 is relatively late, thermal expansion of the shadow mask is not quickly compensated. As a result, the shadow mask 21 in which the stress is concentrated in the transverse direction is bent as shown in the dotted line to generate a dominant phenomenon.

This dominant phenomenon eventually causes a change in the distance between the shadow mask 21 and the panel 11, which changes the position of the electron beam through hole, and naturally prevents the electron beam from landing on the desired phosphor accurately.

Although buffer grooves 24 are formed at the edges of the shadow mask 21 as shown in order to alleviate the dominant phenomenon of the shadow mask 21, this is a limitation in completely compensating for thermal expansion of the shadow mask. .

The domming phenomenon of the shadow mask is continued until the thermal expansion of the shadow mask is alleviated by the expansion of the frame 13 under heat transfer. Therefore, the prevention of the shadowing of the shadow mask during the initial operation of the cathode ray tube is a key factor in the design of the shadow mask assembly.

The present invention has been made to solve the above problems, by adopting a frame having a roller capable of absorbing the lateral expansion of the shadow mask shadow mask assembly for cathode ray tubes that can prevent the dominant phenomenon of the shadow mask. The purpose is to provide.

1 is a schematic cross-sectional view showing a conventional shadow mask assembly.

Figure 2 is an exploded perspective view showing a shadow mask assembly according to the present invention.

3 is a cross-sectional view taken along line III-III of FIG. 2;

<Description of Main Parts of Drawing>

11 Panel 11a fluorescent film

13 ... frame 20 ... shadow mask assembly

21,31 ... shadow mask 24 ... buffer

31a ... electron beam through hole 32, 33 ... roller

32a, 33a ... Spinner 41 ... Frame

41a ... Joint

In order to achieve the above object, a shadow mask assembly for a cathode ray tube according to the present invention includes a shadow mask having an electron beam through hole formed therein; Rollers fixed to both edges of the shadow mask; And a frame on which the rollers are rotatably supported, wherein the rollers rotate to absorb expansion when the shadow mask thermally expands in the lateral direction.

Here, both edges of the shadow mask are welded to the rollers.

In addition, both ends of the roller is formed with a rotating projection, the frame is formed with a coupling hole, the rotation projection is inserted into the coupling hole, the roller is supported by the frame.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Reference is made to FIGS. 2 and 3 showing a shadow mask assembly for a cathode ray tube according to a preferred embodiment of the present invention. As shown in the figure, the shadow mask assembly of the present invention comprises a shadow mask 31 and a frame 41 supporting the same. As described above, the shadow mask assembly is installed to be spaced apart from the panel 11 to which the fluorescent film 11a (see FIG. 1) is applied.

The shadow mask 31 has an electron beam passing hole 31a through which an electron beam emitted from an electron gun (not shown) passes.

According to a feature of the invention, the edges of both ends of the shadow mask 31 are attached and fixed to the rollers 32 and 33, for example by welding or the like. In addition, the rollers 32 and 33 are rotatably coupled to the frame 41. That is, the rotation protrusions 32a and 33a are formed at both ends of the rollers 32 and 33, and the rotation protrusions 32a and 33a are rotatably coupled to the coupling holes 41a formed in the frame 41. .

The rollers 32 and 33 are rotatably coupled to the frame 41 so that the shadow mask 31 is indirectly supported through the rollers 32 and 33, rather than being directly fixed to the frame 41.

Through the operation of the cathode ray tube employing the shadow mask assembly having the structure as described above looks at the function of the shadow mask assembly.

The cathode ray tube is initially driven to emit an electron beam from an electron gun (not shown). The emitted electron beam passes through the shadow mask 31 of the shadow mask assembly after being deflected by a deflection yoke (not shown). At this time, most of the electron beam passes through the electron beam through hole 31a of the shadow mask 31 and a part thereof collides with the shadow mask 31.

The shadow mask 31 collided with the electron beam is gradually heated to expand, and the stress received by the shadow mask 31 is transverse as shown by the arrow D of FIG. 3. In this case, since both ends of the shadow mask 31 are not fixed to the frame 41, the shadow mask 31 is expandable in the lateral direction.

As the shadow mask 31 expands in the lateral direction, the rollers 32 and 33 fixed to both ends are gradually rotated in the directions of the arrows R1 and R2, respectively. Therefore, the stretching due to the lateral expansion of the shadow mask 31 can be compensated for by the rotation of the rollers 32 and 33.

Therefore, as described above, the bending due to the lateral expansion of the shadow mask, that is, the doming phenomenon is prevented.

The shadow mask assembly for a cathode ray tube according to the present invention absorbs thermal expansion of the shadow mask in response to the collision of the electron beam by a rotating roller, thereby preventing the shadow mask from bending, and further allowing the electron beam to be landed on a desired phosphor relatively accurately. Distortion and brightness deterioration can be prevented.

Claims (3)

A shadow mask in which an electron beam passage hole is formed; Rollers fixed to both edges of the shadow mask; And A frame on which the rollers are rotatably supported, And the rollers rotate to absorb expansion when the shadow mask thermally expands in the transverse direction. The shadow mask assembly of claim 1, wherein both edges of the shadow mask are welded to the rollers. The shadow mask assembly for a cathode ray tube according to claim 1, wherein both ends of the roller are provided with rotation protrusions, and the frame has a coupling hole to which the rotation protrusions are coupled.