KR930003472B1 - Frame assemlby for shadow mask - Google Patents

Abstract

The assembly improves the luminance and the resolution of cathod ray tube by minimizing the difference of electron beam drift amount. The first area of section which has no holes divided by 1/6 length of the major axis and 1/6 length of the minor axis is about the same as the second area of section which has no holes divided from 1/6 length of the minor axis to 3/6 length of the minor axis. The ratio of the first area to the second area is within about ±30 %. The shadow-mask having a color selecting function is set on the inside of pannel.

Description

Shadowmask Frame Assembly for Color Cathode Ray Tubes

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

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

Figure 3 is a shadowmask development of the shadowmask frame assembly according to the present invention.

* Explanation of symbols for main parts of the drawings

10: shadow mask frame assembly 11: shadow mask

11a: Perforation (of shadow mask) 11b: Perforation (of shadow mask)

B: Edge (of vertical and horizontal center of shadow mask)

12: frame 13: first area

14: second area A (of no research) A: corner

The present invention relates to a shadow mask frame assembly for a color cathode ray tube, and more particularly to a shadow mask having a color selection function located inside the panel.

In general, the color cathode ray tube is shown in FIG. 1, in which the shadow mask frame assembly 4 in which the shadow mask 2 and the frame 3 are coupled is mounted therein, and the panel 5 and its neck portion ( The funnel 6 in which the electron gun 7 is sealed in 6a) is sealed. In the cathode ray tube 1 configured as described above, the electron beam emitted from the electron gun 7 does not pass all of the electron beam passing holes of the shadow mask 2, but passes only a part of the cathode ray tube 1, thereby forming one pixel. The shadow mask 2 is heated by the failed electron beam, ie, the hot electrons, thereby causing a dominant phenomenon. However, the dominant phenomenon of the shadow mask 2 fixed to the frame 3 is that the vertical and horizontal center edges B of the shadow mask 2 shown in FIG. 2 appear larger than the corner portion A. FIG. Therefore, when correcting the dominant amount of the shadow mask 2 to an absolute amount, the color purity is lowered due to the dominant amount at the edge portion B and the corner portion A, that is, the mislanding difference of the electron beam. That is, the electron beam landing trajectory at the edge portion B when it is emitted from the electron gun 7 and landed on the fluorescent surface is moved in the direction of the center of the shadow mask 2 as the shadow mask 2 is heated. As (3) is heated, the landing trajectory of the electron beam is moved outward of the shadow mask 2, and the landing trajectory of the electron beam at the corner portion A is almost at the time of thermal expansion of the initial shadow mask 2. As the frame 3 is heated and thermally expanded without changing, the frame 3 moves in the outward direction of the shadow mask 2. Therefore, the amount of electron beam mis-landing that lands on the fluorescent surface at the edge portion B and the corner portion A of the horizontal and vertical centers of the shadow mask 2 is different, and the respective portions when correcting the absolute mis-landing amount of the shadow mask 2 are different. The color purity decreases due to the difference in the correction amount.

The difference in mislanding correction amount of the electron beam will be more severe as the skirt portion of the shadow mask is welded to the inner surface of the frame 3. In order to solve the above problems, the skirt portion of the shadow mask 2 is welded to the frame so that the skirt portion is opened to the outside when the shadow mask 2 is domed, or the skirt portion of the rice cake portion is cut out and welded. I could not expect.

The present invention has been made to solve the above problems, by reducing the amount of purity drift (purity drift) by equalizing the initial domming amount at the edges and corners of the horizontal and vertical centers, and further adopts the cathode ray tube It is an object of the present invention to provide a shadow mask frame assembly for color cathode ray tube that can improve the resolution of the.

In order to achieve the above object, the present invention provides a shadow mask frame having a hole portion having a plurality of electron beam through holes, a shadow mask extending outwardly from an edge of the hole portion, and a frame combined with a shadow mask frame for a color cathode ray tube. In the assembly, the length of the long side (L) from the edge of the shadow mask And cross section length Of the first area of the non-perforated area divided by Of short side from the point It is characterized in that the second area of the non-perforated area partitioned up to the point is formed substantially equal.

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

The shadow mask frame assembly 10 for the color cathode ray tube shown in FIGS. 1 and 3 is a shadow mask 11 and a frame 12 in which a plurality of electron beam through holes are formed, and the shadow mask having color selection functions. 11 is provided inside the panel 5 so as to be a predetermined distance from the fluorescent film formed on the inner surface of the panel 5. Here, the shadow mask 11 fixed to the frame 12 has a hole portion 11a having a plurality of electron beam through holes formed therein, and a hole 11b having a predetermined length extending from an edge of the hole portion and having no electron beam through holes formed therein. The shadow mask 11 has a long side length (ℓ) from each edge 11c of the shadow mask 11 in accordance with a feature of the present invention. Of cross section length (L ') Of the first area 13 of the non-perforated part 11b partitioned by Of the shorter side length from the point The second area 14 of the non-pores 11b partitioned up to the point is formed substantially the same. At this time, even if the width ratio of the first area 13 and the second area 14 is formed within approximately ± 30%, the difference between the amount of mis-landing at the edge portion B and the corner portion A of the vertical and horizontal centers. Can be reduced.

Referring to the operation of the shadow mask frame assembly 10 for a color cathode ray tube according to the present invention configured as described above are as follows.

The shadow mask 11 of the shadow mask frame assembly 10 is emitted from the electron gun 7 to be heated by an electron beam that does not pass through the electron beam passing hole of the shadow mask 11, the edge of the shadow mask 11. From (11c) to the length of the long side (ℓ) Of cross section length (ℓ ') Of the first area 13 of the non-perforated part 11b partitioned into and the cross-sectional part length l ' Of short side length (l ') Since the second area 14 of the non-perforated part 11b partitioned to the point is formed equally, the heat content of these 1st, 2nd area is the same, and the corner part A of the said shadow mask 11 is horizontal, And the electron beam drift difference at the edge portion B of the vertical center can be reduced. That is, according to the experiments of the present inventors, when the area ratio of the first area 13 and the second area 14 is 1 to 1.5, the electron beam drift difference between the corner portion A and the edge portion B is approximately. When the area ratio of the areas 13 and 14 of the first and second areas was 1 to 1.3, the electron beam drift difference between the corner portion A and the edge portion B was 35 µm. When the first area B and the second area 14 were set to 1 to 1, the drift difference of the electron beam was 5 m.

As described above, the shadow mask frame assembly for the color cathode ray tube according to the present invention forms the first area and the second area of the shadow mask unperforated portion to be substantially the same, so that the difference in the dominant amount of the corner portion and the edge portion of the horizontal and vertical centers, that is, the electron beam drift amount By minimizing the difference, the absolute dope amount correction of the shadow mask can be made constant throughout the entire area, and further, the brightness and resolution of the cathode ray tube employing the same can be improved.

Claims (2)

A shadow mask having a plurality of electron beam through holes formed therein, a shadow mask having no holes extending outwardly from an edge of the hole, and a frame combined with a shadow cathode tube for a color cathode ray tube, from a corner of the shadow mask. Of long side (ℓ) And cross section length Of the first area of the non-perforated area divided by Of short side from the point A shadow mask frame assembly for a color cathode ray tube, characterized in that the second area of the non-perforated portion partitioned to the point is formed approximately equal. The electron gun for a color cathode ray tube according to claim 1, wherein an area ratio between the first area and the second area is within about ± 30%.