KR20020036588A - Mask assembly for cathode ray tube - Google Patents

Abstract

PURPOSE: A mask assembly of a cathode ray tube is provided to minimize doming of a shadow mask by improving a structure of a mask frame to allow the shadow mask to be expanded in a horizontal direction. CONSTITUTION: A mask assembly of a cathode ray tube comprises a shadow mask(10), a mask frame(20) for supporting the shadow mask(10), many springs(30) for mounting the mask frame(20) to a panel, and an expanding element for allowing the shadow mask(10) to be expanded in a horizontal direction. The mask frame(20) includes a bottom(22) having an electron beam passage aperture, and a side(24) bent from four edges of the bottom(22) toward the shadow mask(10) and welded to a skirt(16) of the shadow mask(10). The expanding element is formed by one or two protruded parts(24a). The protruded part(24a) is formed outward at the side(24) of the mask frame(20) between welding areas for the skirt(16) of the shadow mask(10).

Description

Mask assembly for cathode ray tube {MASK ASSEMBLY FOR CATHODE RAY TUBE}

The present invention relates to a mask assembly for a cathode ray tube, and more particularly to a mask assembly for cathode ray tubes that can minimize the doming phenomenon of the shadow mask by improving the structure of the mask frame so that the shadow mask can expand outward in the horizontal direction. It is about.

In general, a cathode ray tube is a display device in which an image of a three-beam electron beam emitted from an electron gun collides with R, G, and B phosphors in a phosphor film screen to excite the phosphor.

To this end, the cathode ray tube has a panel having a fluorescent screen on its inner surface, an electron gun for emitting an electron beam toward the fluorescent screen, a neck portion for mounting the electron gun therein, and a trumpet shape connecting the panel and the neck portion. And a mask assembly having a funnel and a shadow mask mounted in parallel with the fluorescent screen.

The mask assembly is disposed to be parallel to the screen of the fluorescent film on the inner surface and separates and lands the electron beam emitted from the electron gun to the corresponding phosphor to perform a color discriminating function. As shown in FIG. 1, a plurality of beam passing holes are provided. A shadow mask 110 forming the 112, a mask frame 120 for supporting the shadow mask 110, and a plurality of spring members 130 for fixing the mask frame 120 to the panel.

The shadow mask 110 includes a hole 114 for forming a plurality of beam passing holes 112 for landing the separated three-beam electron beam emitted from the electron gun with the corresponding R, G, and B phosphors, and four holes. The skirt portion 116 is bent from the edge.

In addition, the mask frame 120 serves to support the shadow mask so that the shadow mask 110 is placed at an appropriate position with respect to the panel. The mask frame 120 according to the related art has a shadow mask for easy assembly process. An interval between the 110 and the mask frame 120 is formed equally along the circumferential surface thereof.

That is, the skirt portion 116 of the shadow mask 110 is a plurality of spot welding is performed on the side portion 122 of the mask frame 120 and the four corner portions, and each of the long side portion and the short side portion of the mask frame 120. In this case, a fine gap of about 0.5 to 0.7 mm is formed between the skirt portion 116 of the shadow mask 110 and the side portion 122 of the mask frame 120.

In the mask assembly having such a configuration, when an electron beam is emitted when the cathode ray tube is driven, some of the electron beams collide with the shadow mask 110, thereby raising the temperature of the shadow mask 110 to thermally expand it. .

However, during the thermal expansion, the shadow mask 110 has thermal expansion in the horizontal direction (X-axis and Y-axis direction in FIG. 1) because the skirt portion 116 is in contact with the side portion 122 of the frame 120. Because of this limitation, it eventually expands convexly in the vertical direction (Z-axis direction in Fig. 1) towards the panel.

In this way, the shadow mask 110 is convexly expanded in a vertical direction, which is generally referred to as a domming phenomenon. When the domming phenomenon occurs, the electron beam does not accurately land on the phosphor or emits a different color phosphor. Color purity is lowered.

As described above, according to the conventional mask assembly, since the skirt portion of the shadow mask is in contact with and welded to the side surface of the mask frame, thermal expansion of the shadow mask is made only in the vertical direction, thereby preventing the doming phenomenon from being suppressed.

Accordingly, the present invention is to solve the above problems, by providing a mask assembly for the cathode ray tube that can minimize the shadowing phenomenon of the shadow mask by improving the structure of the mask frame so that the shadow mask can expand outward in the horizontal direction. For the purpose.

1 is an exploded perspective view of a mask assembly for a cathode ray tube according to the prior art.

Figure 2 is an exploded perspective view of a mask assembly for a cathode ray tube according to the present invention.

3 is a bottom view illustrating the coupled state of FIG. 2.

In order to achieve the above object, the present invention, the mask frame for fixing the skirt portion of the shadow mask to enable the horizontal thermal expansion of the shadow mask, to minimize the color expansion of the shadow mask by minimizing thermal expansion in the tube axis causing the phenomenon Provided is a mask assembly for a cathode ray tube that can maintain optimal function.

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

Figure 2 is an exploded perspective view of the mask assembly according to the present invention, Figure 3 is a bottom view showing the coupled state of FIG.

As shown, the mask assembly according to the present invention includes a shadow mask 10, a mask frame 20 for supporting the shadow mask 10, and a plurality of spring members 30 for fixing the mask frame 20 to the panel. ).

The shadow mask 10 has the same curved surface as the screen portion of the panel, and includes a hole portion 14 having a plurality of beam passing holes 12 and bent from four edges of the hole portion 14 to form a mask. It is made of a skirt portion 16 is welded to the mask frame 20 while maintaining the shape.

The mask frame 20 is bent toward the shadow mask 10 from four edges of the bottom portion 22 and the bottom portion 22 having a rectangular beam passing opening, and thus a skirt of the shadow mask 10. And a side portion 24 welded to the portion 16.

Here, the mask assembly according to the present invention provides a means in which the shadow mask 10 is thermally expandable in the horizontal direction (X-axis and Y-axis directions in FIG. 2) in the side portion of the mask frame.

The means comprises a convex portion 24a which convexly forms the side surface portion 24 of the mask frame 20 outward in the horizontal direction (X-axis and Y-axis direction in FIG. 2), and the convex portion 24a is a shadow mask. Is provided in the space between the welded portions to which the skirt portion 16 of the welded portion is welded, preferably in a portion other than the welded portion.

That is, the convex portion 24a may be provided on each side (long side and short side) of the side portion 24 as shown in FIGS. 2 and 3, or the side portion 24 as shown in FIG. 4. Each side may be provided one by one, and if the convex portion 24a is formed as shown in the embodiment of FIG. 4, since the weld portion may be removed from the center of the side portion, the horizontal thermal expansion of the shadow mask 10 may be more effectively performed. Will be.

In addition, the spring member 30 is fixed to the convex portion 24a of the mask frame 20 and a stud formed in the panel to be bent toward the outside of the mask frame 20 and embedded in the panel at one end thereof. It consists of a coupling portion forming a fastening hole for fastening with the pin.

As the convex portion 24a is formed on the side surface portion 24 of the mask frame 20, the skirt portion 16 of the shadow mask 10 and the skirt portion 16 of the shadow mask 10 are fixed while the shadow mask 10 is fixed to the mask frame 20. A predetermined interval is maintained between the convex portions 24a of the mask frame 20.

Therefore, when the electron beam is emitted when the cathode ray tube is driven, some beams of the electron beam collide with the shadow mask 10, thereby raising the temperature of the shadow mask.

At this time, since a predetermined interval is maintained between the skirt portion 16 of the shadow mask 10 and the convex portion 24a of the mask frame 20, the skirt portion of the shadow mask when the temperature rise due to the electron beam collision as described above is maintained. Thermal expansion outside the horizontal direction (X-axis and Y-axis directions in Fig. 2), that is, toward the convex portion is allowed.

Therefore, the amount of domming that convexly expands in the vertical direction (Z-axis direction of FIG. 2) toward the panel as in the prior art is significantly reduced.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the range of.

As described above, the mask assembly according to the present invention forms convex portions of the side surfaces of the mask frame except for the welded portion to enable horizontal thermal expansion of the shadow mask, thereby reducing the amount of doming due to vertical thermal expansion of the mask. It is possible to prevent deterioration of the color screening function, thereby improving the landing characteristics of the electron beam.

Claims (6)

A shadow mask having a hole portion having a plurality of beam passing holes and a skirt portion bent from four edges of the hole portion; A mask frame having a side portion to which the skirt portion is welded; And a plurality of spring members fixed to the side portions of the mask frame and detachably coupled to the stud pins embedded in the panel. And a means for allowing horizontal thermal expansion of the shadow mask in a side portion of the mask frame. 2. A mask assembly for a cathode ray tube according to claim 1, wherein said means comprises a convex portion which convexly forms said side portion outward in the horizontal direction. 3. A mask assembly for a cathode ray tube according to claim 2, wherein said spring member is provided in said convex portion. 4. A mask assembly for a cathode ray tube according to claim 2 or 3, wherein the convex portion is provided in a space between welds to which the skirt portion is welded. The mask assembly for a cathode ray tube according to claim 4, wherein the welding portion is provided at four corner portions of the side portion. 5. The mask assembly for a cathode ray tube according to claim 4, wherein the weld portion is provided at four corner portions of the side portions and at the center of each side of the side portions.