KR940008155Y1 - Shadow mask flame assembling apparatus for c-crt - Google Patents

Abstract

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Description

Shadowmask Frame Assembly for Color Cathode Ray Tubes

1 is a cross-sectional view of a typical cathode ray tube.

2 is a perspective view of a conventional shadowmask frame assembly.

3 is a perspective view showing a shadow mask frame assembly for a color cathode ray tube according to the present invention.

4 is a cross-sectional view of the shadow mask frame assembly shown in FIG.

* Explanation of symbols for main parts of the drawings

20: shadow mask 21: hole

22: no study 23: skirt

30: frame

The present invention relates to a color cathode, and more particularly to a shadow mask frame assembly fixedly installed in a panel.

In general, as shown in FIG. 1, a colored cathode ray tube is fixedly provided with a shadow mask frame assembly 10 inside a panel 2 in which a fluorescent film 2a is formed on an inner surface thereof. It is sealed with the funnel 4 in which the electron gun 5 and the deflection yoke 6 were provided in the inside and the outside of the part 4a. In the cathode ray tube 1 configured as described above, the electron beam emitted from the electron gun 5 is deflected by the deflection yoke 6 so that the fluorescent film 2a is landed at each fluorescent point to form one pixel. The pixels come together to form a screen. However, the electron beam emitted from the electron gun 5 does not pass all of the electron beam passing holes 11a of the shadow mask 11 having a color discrimination function, but only partially passes through the electron beam. Accordingly, the electron beam that does not pass through heats the shadow mask 11, and the heated shadow mask 11 is thermally expanded to deform the hole portion in which the electron beam passing hole is formed, thereby decomposing the electron beam emitted from the electron gun 5. It will not land correctly on the fluorescent film.

As described above, the deformation of the shadow mask 11 becomes more severe as the cathode ray tube 1 increases in size, as shown in FIG. 2 to reduce the dominant phenomenon that increases as the shadow mask 11 increases in size. Similarly, the method in which the skirt portion 11b of the shadow mask 11 is in contact with the inner surface of the frame 12 is employed. However, since the shadow mask 11 is fixedly installed inside the frame 12, the curvature of the upper and short sides of the frame 12 is the same as the curvature of the shadow mask 11. There was a problem that the shadowing mask 11 could not be reduced as much as desired. In more detail, since the skirt portion 11b of the shadow mask 11 is fixedly installed on the inner surface of the frame 12, the thermal expansion force of the shadow mask 11 is expanded in the expansion direction of the shadow mask 11. Since the skirt 11b is supported by the long and short sides 12a and 12b of the frame 12, the shadow mask 11 is restricted in the direction in which the thermal expansion force of the shadow mask 11 travels. The phenomenon is intensifying.

The limitation of the thermal expansion force due to the long and short sides 12a and 12b of the frame 12 is severely shown in the X-axis direction in the horizontal direction when the shadow type shadow mask 11 is mounted. Therefore, as the dominant amount of the shadow mask 11 is severely shown, the electron beam emitted from the electron gun does not land correctly on the fluorescent film 2a of the panel 2, and thus a cathode ray tube having a high resolution cannot be manufactured. .

The present invention was created in order to solve the above problems, by minimizing the amount of shadow mask supported on the frame so that the electron beam emitted from the electron gun can be accurately landed on the fluorescent film to improve the resolution of the cathode ray tube employing it. Furthermore, the object of the present invention is to provide a shadow mask frame assembly for a color cathode ray tube that can improve the product value of a product.

In order to achieve the above object, the present invention is mounted on the inside of the panel, the shadow mask frame assembly for the color cathode ray tube is fixed to the frame and the skirt portion of the shadow mask on the inner side of the long side, short side of the frame, the shadow The radius of curvature of the mask long side and the short side is characterized by being formed larger than the radius of curvature of the top edge of the frame long and the short side wall.

Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

The shadow mask frame assembly for a color cathode ray tube according to the present invention is fixedly installed in a panel sealed with a funnel, and as shown in FIG. 3, a hole 21 having a plurality of electron beam through holes 21 a formed therein; A shadow mask 20 having a non-perforated portion 22 extending a predetermined length from an edge of the perforated portion 21 and a skirt portion 23 bent in a direction perpendicular to the non-perforated portion 22; The skirt portion 23 of the shadow mask 20 has a frame 30, which is welded and fixed to the inner side of the long side, short side wall portions 31, 32; is configured to include, the shadow mask ( The long side of the frame 30, that is, the long side portion L and the short side portion S of the non-perforated part 22 or the perforated part 21, has a long radius of curvature R1 and R2. It is formed smaller than the top edge curvature radius R3 (R4) of the side wall part 31 and the short side wall part 32. As shown in FIG. Herein, the radius of curvature R1 of the long and short edge portions L of the shadow mask 20 may be 1.2 to 1.45 times smaller than the radius of curvature R3 of the upper edge of the long side wall portion 31 of the frame 30. The radius of curvature R2 of the short side portion S of the shadow mask 20 may be 1.3 to 1.5 times smaller than the radius of curvature R4 of the upper edge of the short side wall portion 32 of the frame 30. The radius of curvature R4 of the upper edge of the short side wall portion 32 of the frame 30 may be larger than the curvature R3 of the long side wall portion 31.

Referring to the operation of the shadow mask frame assembly for a color cathode ray tube according to the present invention configured as described above are as follows.

The shadow mask frame assembly is heated by hot electrons that do not pass through the electron beam passing hole of the shadow mask 20 by being emitted from the electron gun, and thus the shadow mask 20 is thermally expanded in the X and Y axis directions. The radius of curvature R1 (R2) of the long short side portion L (S) of 20 is smaller than the radius of curvature R3 (R4) of the upper edge of the long, short side wall portions 31, 32 of the frame 30. Since the support force of the long side and short sidewall portions 31 and 32 with respect to the thermal expansion progress direction of the shadow mask 20 can be reduced, the amount of dominance of the shadow mask 20 can be greatly reduced. To describe this in more detail, the radius of curvature R3 (R4) of the upper edges of the frame 30 and the upper side edge portions 31 and 32 of the frame 30 is the long edge portion L of the shadow mask 20. Since the radius of curvature R1 is larger than the radius R1 of R, as shown in FIG. 4, the lower end of the skirt 23 of the shadow mask 20 is formed on the long and short side walls of the frame 30. The welding is fixed to the inner surface of the portion (31) (32). If the shadow mask 20 is deeply inserted into the frame 30, the contact area of the skirt 23 with the inner surface of the long side and short side walls 31 and 32 will be widened. However, since they have different curvature radii, the gaps due to the difference in curvature radii, that is, the long edges (L) (S) of the upper edges of the long side walls 31 and 32 and the shadow mask 20, S The gap W between) still exists. Therefore, as shown in FIG. 4, the lower end of the skirt 23 is brought into contact with the upper end of the inner side of the long side and short side walls 31 and 32 of the frame 30, and thus, by the electron beam emitted from the electron gun. Constraints according to the thermal expansion direction of the heated shadow mask 20 are reduced so that the thermal expansion amount in the shadow thermal expansion main direction of the shadow mask 20 is absorbed by the bending of the skirt portion 23, and the shadow mask 20 is relatively Doming will be reduced.

According to the experiments of the inventors of the shadow mask 20 dominant relationship of the shadow mask frame assembly 40 according to the present invention was able to obtain the following results.

TABLE 1

only ; R1 and R2 are the radius of curvature of the shadow mask long and short sides, respectively, and R3 and R4 are the radius of curvature of the upper edge of the long and short side walls of the frame, respectively.

In addition, the dominant amount measuring portion of the shadow mask is 2/3 of the X axis of the effective screen.

As can be seen from the table, the shadow mask is formed by forming the radius of curvature of the long and short sides of the shadow mask 20 smaller than the radius of curvature of the upper edge of the long and short side walls 31 and 32 of the frame 30. Doming phenomenon of (20) can be significantly reduced. In particular, the radius of curvature of the long side portion (L) of the shadow mask 20 is greater than 1.4 times the radius of curvature (R3) of the upper edge of the long side wall portion 31 of the frame 30, and of the shadow mask 20 When the radius of curvature R2 of the short side portion S was 1.3 times larger than the radius of curvature R4 of the short side wall portion 32 of the frame 30, the doming phenomenon was minimized.

In this way, the shadow mask frame assembly for the color cathode ray tube of the present invention forms a curvature radius of the long and short side portions of the shadow mask to be larger than the radius of curvature of the long and short side walls of the frame, thereby minimizing the doming phenomenon due to thermal expansion of the shadow mask. This has the advantage of improving the resolution of the cathode ray tube employing.

Claims (3)

In the shadow mask frame assembly for a color cathode ray tube mounted on the inside of the panel, the skirt and the skirt portion of the shadow mask is fixed to the inner side of the frame, the long side and the short side of the frame, each of the long and short sides of the shadow mask 20 Shadow mask frame assembly for color cathode ray tube, characterized in that the radius of curvature (R1) (R2) is formed larger than the radius of curvature (R3) (R4) of the upper edge of the frame 30, short side walls (31) (32) . The shadow mask frame assembly for color cathode ray tubes according to claim 1, wherein a radius of curvature R3 of the long side wall portion of the frame 30 is larger than a radius of curvature R4 of the short side wall portion. The method of claim 1, wherein the radius of curvature (R2) of the short side portion of the shadow mask 20 is formed to be 1.3 to 1.5 times smaller than the radius of curvature (R3) of the upper edge of the frame 30 short side wall portion, The radius of curvature R4 of the upper edge of the short side wall portion 32 is larger than the radius of curvature R3 of the upper edge of the long side wall portion 31.