JPS6349337B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color picture tube, particularly to a shadow mask structure of a shadow mask type color picture tube.

[Prior Art] Generally, a color picture tube, as shown in FIG. 2, includes a neck portion 1, a funnel-shaped funnel portion 2, and a panel portion 3 disposed at the open end of the funnel portion 2.
A fluorescent surface 5 formed on the inner surface of the face plate 4 of the panel portion 3, and a shadow mask 6 disposed at a predetermined distance from the fluorescent surface 5.
and an electron gun 7 housed in the network section 1. Further, the shadow mask 6 having the above structure has a structure as shown in FIGS. 3a, b, c, and d. That is, figure a is a front view of the main part of the shadow mask 6 seen from the panel part 3, and figure b is a front view of the shadow mask 6 shown in figure a.
A' cross-sectional view, Figure c is a rear view of the main part of the shadow mask 6 seen from the back, and Figure d is a perspective view. In these figures, the shadow mask 6 has a perforated part 6a having a large number of slot holes through which electron beams pass, and a spherical surface on the front side facing the fluorescent screen 5, including the perforated part 6a. This shadow mask effective surface 6b
It is composed of a skirt portion 6c and a corner portion 6d, which provide mechanical strength to the structure.

The shadow mask of a color picture tube constructed in this way is generally rolled 0.10 to 0.2 mm thick.
A cold-rolled steel plate for a shadow mask with a thickness of
In order to form a large number of openings for the electron beam to pass through by etching, and after cutting the iron plate for each shadow mask, annealing is performed to remove internal stress, and work hardening is performed to sufficiently withstand press shaping. Then, it is passed through a leveler process and press-molded to form the shape of the shadow mask to form a predetermined curved surface. The shadow mask 6 configured in this way has a skirt portion 6c.
is welded and fixed to the support frame 8 (see Fig. 2). This support frame 8 is provided with a plurality of springs (not shown), and by coupling these springs with pins on the inner surface of the panel 3, the shadow mask 6 is positioned at a predetermined level with respect to the fluorescent surface 5 on the inner surface of the panel 3. placed in a fixed position.

[Problem that the invention seeks to solve]

However, the color picture tube shadow mask 6 with the above configuration has an effective surface 6 as described above.
Since b is formed by stretch molding, and the skirt portion 6 and corner portion 6d are each formed into a predetermined shape by drawing, in addition to the spring back that occurs due to normal bending, compression occurs on the effective surface side as shown in Fig. 3d. Tension acts on the tension and skirt sides, increasing the spring back after press forming, which has a negative effect such as distorting the overhanging molded shape of the effective surface 6b, and is extremely weak in terms of rigidity. , usually it has to be fixed to the support frame 8 by welding and integrated.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to eliminate the above-mentioned drawbacks, and to provide a color picture tube equipped with a shadow mask that prevents the spring back of the skirt portion from having an adverse effect on the effective surface. There is a particular thing.

[Means for solving problems]

In order to achieve this object, the color picture tube according to the present invention has a skirt portion of its shadow mask having a shape having a predetermined curvature in a plane perpendicular to the tube axis.

[Effect]

By giving the skirt portion a curvature similar to that of the effective surface, the occurrence of spring back is eliminated.

[Example] Figures 1a, b, c, and d are front views of essential parts showing examples of color picture tubes, particularly shadow masks, according to the present invention, sectional views along A-A', sectional views along B-B',
It is a rear view of the main part. In the figure, 10 is a shadow mask, and this shadow mask 10 has a plurality of slot holes arranged in its perforated portion 10a. Further, in this shadow mask 10, the effective surface 10b including the perforated portion 10a is formed into a curved shape, and the direction in which this curved surface extends is the screen direction. The long-side skirt portion 10c of the shadow mask 10 has approximately the same curvature as the protruding shape of the effective surface 10b, and extends in the screen direction. That is, the effective surface 10b
As shown in the cross-sectional view of FIG. In addition, the short side direction is shown in the figure c.
As shown in the sectional view B', the skirt portion 10c is bent at a substantially right angle to the effective surface 10b so that the effective surface 10b is substantially flat.

In the color picture tube shadow mask configured in this manner, the relationship between the protruding curvature of the effective surface 10b and the curvature of the skirt portion 10c is almost the same, so that there is no influence caused by drawing and elongation due to press molding. In other words, the skirt 10c can be formed in such a state that there is no springback, or even if it exists, it will not cause any problem in the subsequent process, and there will be no springback of the skirt 10c, and the same effect as described above can be obtained. Further, the same effect can be obtained even when the curvatures of the two are different.

In addition, in the above embodiment, the case where a slot hole type shadow mask was used was explained, but the present invention is not limited to this, and even when a circular hole type shadow mask is used, the same effect as described above is achieved. Needless to say, it is effective.

Further, in the above embodiment, the case where the curved surface is formed into an arc shape has been explained, but the present invention is not limited to this, and the curved surface may be formed into a quadratic curve, a cycloid curve, a plurality of straight lines, etc. as described above. Needless to say, the same effect can be obtained.

〔Effect of the invention〕

As explained above, according to the shadow mask for a color picture tube according to the present invention, it is possible to obtain a shadow mask that is extremely stable and highly rigid compared to a shadow mask having a skirt portion of a conventional shape.
Furthermore, since the effect on the effective surface of the shadow mask during molding can be reduced, it is extremely effective against stretch strain. Furthermore, since the strength of the shadow mask can be maintained without the use of a support frame that maintains the strength, various excellent effects can be obtained, such as eliminating the need for the support frame in terms of reducing production costs.

[Brief explanation of drawings]

FIGS. 1a, b, c, and d are a front view of a main part showing an embodiment of a color picture tube, particularly a shadow mask, according to the present invention, a cross-sectional view along A-A', a cross-sectional view along B-B', a rear view of a main part, Fig. 2 is a cross-sectional view of essential parts showing an example of a shadow mask type color picture tube, Fig. 3 a, b, c,
d is a front view of main parts, a sectional view taken along line AA', a back view of main parts, and a perspective view of an example of a conventional color picture tube shadow mask. DESCRIPTION OF SYMBOLS 1...Network part, 2...Funnel part, 3...Panel part, 4...Face plate, 5...Fluorescent surface, 6...
Shadow mask, 6a... effective part, 6b... effective surface,
6c...Skirt part, 6d...Corner part, 7...Electron gun, 8...Support frame, 10...Shadow mask, 10a...Perforated part, 10b...Effective surface, 10c...
Skirt part, 10d...corner part.

Claims (1)

[Scope of Claims] 1. A shadow mask type comprising a fluorescent surface constituting a screen, and a shadow mask having an effective surface including a perforated portion and a skirt portion, and aligning the collision point of an electron beam with the fluorescent surface. In the color picture tube, the skirt portion is located at the center of the fluorescent surface and extends substantially parallel to a tube axis perpendicular to the fluorescent surface, and in a plane perpendicular to the tube axis. At least a pair of opposing skirt portions have a curvature, the direction of the curvature is a direction that maximizes the distance between the pair of opposing skirt portions at the center of the effective surface, and the shaping/folding direction of the skirt portion and the A color picture tube equipped with a shadow mask characterized in that its effective surface extends in the same direction. 2. The color picture tube according to claim 1, wherein the curvature of the skirt portion in a plane orthogonal to the tube axis and the curvature of the effective surface projection in the tube axis direction are approximately the same.