KR100261453B1 - Mask frame for cathode ray tube - Google Patents

Abstract

PURPOSE: A mask frame for cathode ray tube is provided to correct the doming effect of a shadow mask and enhance the strength of a mask frame by forming a twofold mask frame. CONSTITUTION: A mask frame for cathode ray tube is formed with a double mask frame(20). The double mask frame(20) comprises an inner frame member(44) and an outer frame member(46). The inner frame member(44) and the outer frame member(46) are formed with different materials, respectively. The inner frame member(44) is formed with the material having a thermal expansion coefficient bigger than the outer frame member(46).

Description

Mask frame for cathode ray tube

The present invention relates to a mask frame for a cathode ray tube, and more particularly, to a mask frame capable of improving the strength and early correction of the shadowing phenomenon of a shadow mask while using a smaller amount of material.

Generally, the cathode ray tube forms a fluorescent screen including patterned green, blue and red phosphors on the inner surface of the panel, which is the front body, and mounts the electron gun to the neck of the funnel, which is the rear body. The electron gun emits three stem electron beams which are controlled by respective green, blue, and red screen signals, and the electron beams pass through respective beam passing holes formed by the shadow mask before reaching the fluorescent screen. Landing separated allows accurate color realization. As such, the shadow mask, which is responsible for the color discrimination function, is supported by the mask frame and mounted on the inner surface of the panel.

9 is a combined perspective view of a mask assembly according to the prior art, and as shown, the shadow mask 1 forms the same curvature as the screen portion of the panel and has a curved portion 5 having a plurality of beam passing holes 3. And a skirt portion 9 which is bent from the curved portion 5 toward the mask frame 7. The mask frame 7 includes a base plate 13 forming an opening 11 through which an electron beam passes, and a flange 15 bent toward the shadow mask 1 along an edge of the base plate 13. Is done. The shadow mask 1 may be mounted on the mask frame 7 by bringing the skirt portion 9 of the shadow mask 1 into contact with the flange portion 15 of the mask frame 7 and then performing a welding operation. . The mask frame 7 is made of a relatively thick steel sheet material, the thickness is about 0.8 ~ 1.4mm.

At this time, the shadow mask (1) is a very thin steel sheet material compared to the mask frame (7), a doming phenomenon in which the curved portion (5) is convexly expanded toward the panel due to the rise of thermal energy due to electron beam scanning This happens. Therefore, the mask frame 7 should be designed to support the shadow mask 1 as well as to cope with thermal deformation of the shadow mask 1.

However, recently, since the cathode ray tube tends to be enlarged in size, the shadow mask is also enlarged in size, and as the size increases, the shadowing phenomenon easily occurs, and in most cases, the shadow mask is prevented by applying a tensile force to the shadow mask. Therefore, the mask frame is also enlarged and its thickness is increased for the purpose of improving the strength for supporting the tensile force.

However, as the thickness of the mask frame increases, the weight increases, which affects the weight of the cathode ray tube, and the secondary thermal deformation of the mask frame for correcting shadowing of the shadow mask after primary shadowing of the shadow mask by electron beam scanning. This takes a considerable amount of time, so that the shadowing of the shadow mask cannot be corrected early.

Therefore, the present invention was devised to solve the above problems, and an object of the present invention is to provide a cathode ray tube mask frame capable of improving the strength while prematurely correcting the shadowing phenomenon of a shadow mask while using a smaller amount of material. To provide.

1 is a schematic cross-sectional view of a cathode ray tube equipped with a mask frame according to the present invention.

2 is a perspective view of a mask frame according to a first embodiment of the present invention.

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

4 is a perspective view of a mask frame according to a second embodiment of the present invention.

5 is a cross-sectional view of a mask assembly mounted with a shadow mask on the mask frame of FIG.

FIG. 6 is a cross-sectional view of the mask assembly illustrating a state in which thermal deformation occurs in FIG. 5. FIG.

7 is a cross-sectional view of a mask assembly including a mask frame according to a third embodiment of the present invention.

FIG. 8 is a cross-sectional view of the mask assembly illustrating a state in which thermal deformation occurs in FIG. 7. FIG.

9 is a perspective view of the combination of the mask assembly according to the prior art.

In order to achieve the above object, the present invention provides a cathode ray tube mask frame comprising a base plate having an opening having a predetermined size for passing an electron beam, and a flange portion bent from an edge of the base plate to be welded to a shadow mask. The mask frame includes a combination of an inner frame member and an outer frame member disposed with a predetermined space therebetween to provide a mask frame for a cathode ray tube, characterized in that to form a two-ply mask frame.

The inner frame member and the outer frame member may be made of the same material, and the inner frame member may be made of a material having a thermal expansion coefficient greater than that of the outer frame member.

In order to achieve the above object, the present invention is a mask frame for a cathode ray tube comprising a base plate having an opening of a predetermined size for passing the electron beam, and a flange portion bent from the edge of the base plate to be welded to the shadow mask In the mask frame is provided by the combination of the inner frame member and the outer frame member is formed in close contact provides a mask frame for cathode ray tube, characterized in that to form an integrated two-layer mask frame.

The inner frame member may be made of a material having a thermal expansion coefficient greater than that of the outer frame member.

As the mask frame is composed of two layers as described above, the strength can be improved without increasing the thickness, and the doming phenomenon of the shadow mask can be corrected early by the bi-metal action.

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

1 is a schematic cross-sectional view of a cathode ray tube equipped with a mask frame according to the present invention, the cathode ray tube having an electron gun with a panel 4 and a neck portion 6 as a front body for forming a fluorescent screen 2 on an inner surface thereof. (8) is inserted into the mounting and consists of a combination of the funnel 12, the rear body for mounting the deflection yoke 10 to the outer peripheral surface. The shadow mask 14 mounted on the rear surface of the panel 4 at equal intervals forms a plurality of beam passing holes 16 corresponding to the phosphor pattern of the phosphor screen 2.

The three stem electron beam 18 emitted from the electron gun 8 is able to sequentially scan all the phosphors of the fluorescent film screen 2 while deflecting up, down, left, and right under the influence of the deflection magnetic field generated by the deflection yoke 10. In this case, the electron beam 18 passes through the beam passing hole 16 of the shadow mask 14 before reaching the fluorescent screen 2 and is separated and landed into the corresponding green, blue, and red phosphors, respectively. Implement color.

As such, the shadow mask 14, which is responsible for the color discrimination function, is supported by the mask frame 20, and the mask frame 20 is fixed to the inner surface of the panel 4 by the coupling spring 22. ) To mount the shadow mask 14 to the inner side of the panel 4.

FIG. 2 is a perspective view of a mask frame according to a first embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along line AA of FIG. 2, wherein the mask frame 20 includes a base plate forming an opening 26 through which an electron beam passes. 28 and a flange portion 30 which is bent from the edge of the base plate 28, the mask frame 20 according to an embodiment of the present invention is in particular arranged inside a predetermined space therebetween Combination of the frame member 32 and the outer frame member 34 forms a two-ply mask frame 20.

The inner frame member 32 and the outer frame member 34 are coupled to each space forming portion so as to be disposed with a predetermined space therebetween, which is a plan at the end of the inner flange portion formed by the inner frame member 32, respectively. The first space forming portion 36 is bent at a predetermined angle toward the outside of the branch portion 30, and at the end of the outer base plate formed by the outer frame member 34 toward the inside of the opening 26 It is made by forming a second space forming portion 38 that is bent at an angle.

In addition, the inner frame member 32 and the outer frame member 34 are coupled to each other to form an integral mask frame 20 by forming a coupling portion, for this purpose, the inner frame member 32 is a flange portion 30 A first coupling part 40 that is bent in an extension line of the first space forming part 36 to be parallel to the second frame part, and the outer frame member 34 is parallel to the base plate part 28. The second coupling part 42 is formed to be bent along the extension line of the forming part 38.

The inner frame member 32 and the outer frame member 34 are in contact with the first coupling part 40 and the second coupling part 42. Preferably, the welding operation is performed with the coupling parts 40 and 42. The inner frame member 32 and the outer frame member 34 are integrally coupled to each other.

The inner frame member 32 and the outer frame member 34 may be made of the same steel material, the thickness of each of the inner frame member 32 and outer frame member 34 is 0.8 ~ 1.4 of the thickness of the conventional mask frame It can be manufactured from 0.4 to 0.5 mm thinner than mm.

Accordingly, the mask frame 20 has a lighter weight using a smaller amount of material than in the related art, and at the same time, the mask frame 20 has an improved strength characteristic due to the structure of the two-ply structure having a hollow shape.

4 is a perspective view of a mask frame according to a second embodiment of the present invention. As shown, the mask frame 20 according to the second embodiment has a predetermined interval, similar to the mask frame according to the first embodiment. The inner frame member 44 and the outer frame member 46 are combined to form a two-layer mask frame 20, but the inner frame member 44 and the outer frame member 46 are different from each other. It is made of steel material.

That is, the inner frame member 44 is made of a material having a coefficient of thermal expansion larger than the coefficient of thermal expansion of the outer frame member 46, for example, the inner frame member 44 is a cold rolled steel sheet (SCP in the KS standard) It is preferable that the outer frame member 46 is made of stainless steel having a coefficient of thermal expansion smaller than that of the cold rolled steel sheet.

As such, the inner frame member 44 made of a relatively high expansion material and the outer frame member 46 made of a low expansion material are combined to form an integrated mask frame 20, so that the mask frame 20 is made of bimetal ( bi-metal is more effective in correcting shadowing of shadow masks. This will be described in more detail below.

FIG. 5 is a cross-sectional view taken along line BB of FIG. 4 illustrating a state in which a shadow mask is mounted on the mask frame shown in FIG. 4, and as shown, the shadow mask 14 is the skirt portion 48 of the mask frame 20. By welding to the frame member 44 and mounted to the mask frame 20, the panel member 44 is disposed at a predetermined distance from the panel.

However, during the action of the cathode ray tube, approximately 15-18% of the electron beam 18 emitted from the electron gun passes through the beam passing hole 16 of the shadow mask 14 to reach the panel surface, but the beam passing hole 16 The majority of the electron beams 18 that do not pass through thermally expand the shadow mask 14, resulting in a domming phenomenon (shown by dashed lines).

At this time, since the mask frame 20 is bimetallized by the combination of the inner frame member 44 made of a high expansion material and the outer frame member 46 made of a low expansion material, the mask frame 20 caused by scanning the electron beam 18 ( As shown in FIG. 6, the thermal deformation of 20) causes the inner frame member 44 to expand more than the outer frame member 46, resulting in the deformation of the mask frame 20 toward the outside thereof.

Accordingly, the skirt portion 48 of the shadow mask 14 welded to the mask frame 20 and the skirt portion 48 of the shadow mask 14 may be deformed along the deformation direction of the mask frame 20 so that the curved portion 54 of the shadow mask 14 may have a doming phenomenon. It can be repositioned to its initial position before it occurs and maintain a constant distance from the panel.

As such, due to the bimetal action of the inner frame member 44 and the outer frame member 46, the mask frame may stabilize the shadowing phenomenon of the shadow mask early.

Next, a third embodiment of the present invention will be described. 7 is a cross-sectional view of a mask assembly including a mask frame according to a third embodiment of the present invention, wherein the mask frame 20 according to the present embodiment has an inner frame member 50 and an outer frame member 52 formed in close contact with each other. Combination of to form an integrated two-ply mask frame 20.

The inner frame member 50 is made of a material having a thermal expansion coefficient greater than that of the outer frame member 52 to impart a bimetal characteristic to the mask frame 20. For this purpose, the inner frame member 50 is It is preferably made of cold rolled steel sheet (SCP as KS standard), and the outer frame member 52 is preferably made of stainless steel having a coefficient of thermal expansion smaller than that of the cold rolled steel sheet.

In the action of the cathode ray tube, the majority of the electron beams 18 do not pass through the beam passing holes 16 of the shadow mask 14, but dooming phenomenon of thermally expanding the shadow mask 14 to convexly expand the curved portion 54. (Shown by the dashed line) is as described above.

At this time, since the mask frame 20 is bimetallized by the close coupling between the inner frame member 50 made of a high expansion material and the outer frame member 52 made of a low expansion material, the mask frame 20 is formed by electron beam scanning. As shown in FIG. 8, thermal expansion of the inner frame member 50 causes thermal deformation toward the outer frame member 52, and accordingly, a skirt portion of the shadow mask 14 welded to the inner frame member 50 is formed. 48) Also, the curved portion 54 of the shadow mask 14 may be repositioned along the deformation direction of the mask frame 20 to the initial position before the domming phenomenon occurs.

As such, the mask frame 20 may correct the dominant phenomenon of the shadow mask 14 by a bimetallic action, and each inner frame member 50 and the outer frame member 52 may have their thicknesses respectively. It forms in 0.4-0.5mm.

As described above, the present invention can have a reduced thickness compared to the conventional mask frame, thereby reducing the weight of the mask frame, and when the two layers are arranged with the hollow interposed therebetween, the strength of the mask frame due to the structural characteristics of the hollow structure. In addition, the doming phenomenon of the shadow mask can be corrected by determining the material of the inner frame member and the outer frame member so as to have different coefficients of thermal expansion and bimetalizing the mask frame.

Claims (15)

A mask frame for a cathode ray tube comprising a base plate having an opening having a predetermined size for passing an electron beam, and a flange portion bent from an edge of the base plate to be welded to a shadow mask, wherein the mask frame has a predetermined space therebetween. Mask frame for a cathode ray tube, characterized in that the combination of the inner frame member and the outer frame member disposed to form a two-layer mask frame. The mask frame for a cathode ray tube according to claim 1, wherein the inner frame member is made of the same material as the outer frame member. The mask frame for a cathode ray tube according to claim 1, wherein the inner frame member is made of a material having a coefficient of thermal expansion larger than that of the outer frame member. The mask frame for a cathode ray tube according to claim 3, wherein the inner frame member is made of a cold rolled steel sheet. 4. The mask frame for cathode ray tube according to claim 3, wherein the outer frame member is made of stainless steel. The mask frame for cathode ray tube according to claim 1, wherein the inner frame member and the outer frame member have a thickness of 0.4 to 0.5 mm, respectively. The method of claim 1, wherein the inner frame member is bent at a predetermined angle toward the outside of the flange portion at the end of the flange portion, and the first space forming portion to be coupled to the outer frame member extension Mask frame for cathode ray tube to form a first coupling portion that is bent in parallel to the flange portion in a line. The mask frame for a cathode ray tube according to claim 7, wherein a welding operation is performed to the first coupling portion. The method of claim 1, wherein the outer frame member is formed at the end of the base plate toward the opening to be formed at a predetermined angle toward the inside of the opening at a predetermined angle, the second space forming to be combined with the inner frame member A cathode ray tube mask frame forming a second coupling portion that is bent to be parallel to the base plate on an extension line of the portion. The mask frame for a cathode ray tube according to claim 9, wherein a welding operation is performed to the second coupling portion. A mask frame for a cathode ray tube comprising a base plate having an opening having a predetermined size for passing an electron beam, and a flange portion which is bent from an edge of the base plate to be welded to a shadow mask, wherein the mask frame is in close contact with an inner frame. A mask frame for a cathode ray tube, characterized in that the combination of the member and the outer frame member to form an integrated two-ply mask frame. The mask frame for a cathode ray tube according to claim 11, wherein the inner frame member is made of a material having a coefficient of thermal expansion larger than that of the outer frame member. The mask frame for a cathode ray tube according to claim 12, wherein the inner frame member is made of a cold rolled steel sheet. The mask frame for a cathode ray tube according to claim 12, wherein the outer frame member is made of stainless steel. 12. The mask frame for cathode ray tube according to claim 11, wherein the inner frame member and the outer frame member have a thickness of 0.4 to 0.5 mm, respectively.