JPS6015240Y2 - Color picture tube internal magnetic shield fixing structure - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an internal magnetic shield fixing structure for a color picture tube.

Regarding shadow mask type color picture tubes, as shown in Fig. 1, a color picture tube usually has an electron gun 1 that emits an electron beam and a thin metal plate 2 with many electron beam passage holes fixed to a support 3. A so-called shadow mask 4 is provided inside the envelope 5, and a fluorescent surface 7 is formed on the inner surface of the front portion 6 at a certain distance from the shadow mask, facing the shadow mask.

Furthermore, an electronic shield 8 is provided to prevent reflected electrons or secondary electrons of the electron beam due to overscanning that are incident on the inner surface of the envelope 5 or the shadow mask from entering the fluorescent surface 7.

The electron beam is designed to pass through the passage hole of the shadow mask 4 and enter a predetermined fluorescent surface.
Due to the influence of external magnetism, a force is applied in a direction perpendicular to the direction in which the magnetism acts, causing a shift in the positional relationship between the electron beam and the fluorescent surface.

As a color picture tube, it is usually affected by the earth's magnetism, which cannot be ignored.

In order to deal with the above problem, it is well known that a magnetic barrier 9 made of an iron plate or the like is provided around or inside the envelope 5.

When fixing the magnetic barrier, especially the internal magnetic barrier, the high voltage, internal vacuum, and structural limitations of the color picture tube must be fully considered, and workability and cost evaluations must also be evaluated in advance. Although many proposals have been made and many examples of fixing methods have been put into practical use, until now there have been few methods that fully satisfy the above conditions.

One of the recently devised methods of fixing an internal magnetic barrier body is
As shown in FIG. 2, a plurality of pins 10 are attached to the shadow mask support 3 by a method such as welding, and a part of the electronic barrier 8 and the internal magnetic barrier 9 are passed through the pins 10 and made of, for example, a spring material. There is a method of inserting the metal fittings 11.

This method is advantageous in terms of workability and cost, and has been put into practical use to some extent.

However, it is common to form a blackened film on the surface of the internal magnetic shield 9 for heat radiation properties, and when fixing with the metal fitting 11, the lower end surface 12 of the metal fitting, that is, the internal magnetic shield The surface in contact with 9 may damage the blackened film of the internal magnetic shield, and the scraped blackened film may fall onto the electron gun or shadow mask, causing sparks or blocking the beam path. This is one of the causes of a significant deterioration in the quality of color picture tubes.

This invention proposes an improvement to the internal magnetic barrier fixing structure in order to eliminate the above-mentioned drawbacks.

The features of this invention will be explained below using the drawings.

As shown in FIG. 2, in the example in which the conventional fixture is used, the lower end 12 of the fixture 11 is embedded in the blackened film surface (not shown) of the internal magnetic shield 9.

FIG. 3 shows an example in which the fixing fitting 13 is applied to the fixing structure of the present invention, and since the lower end portion 14 has a curvature, it does not have the effect of scraping the blackened film surface.

As is known, there is also a method of removing the corners of the metal fittings by tamping, etc., but this increases the number of manufacturing steps and is disadvantageous in terms of time.

This idea can be easily applied at the same time as manufacturing the metal fittings, so it not only strengthens the fixation of the internal magnetic barrier of the color picture tube without increasing costs, but also makes it possible to remove the blackened film by using the fixing metal fittings. However, it has excellent features such as being able to prevent the occurrence of sparks due to the peeling and clogging of the shadow mask.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a color picture tube to which an internal magnetic barrier is applied, Figure 2 a is a support with multiple pins attached, and b is a conventional internal magnetic barrier to which a fixing metal fitting is applied. FIG. 3A is a sectional view of a fixing part, C is a front view of a conventional internal magnetic barrier fixing part to which fixing metal fittings are applied, and FIG. 3A is a front view of the fixing structure of the present invention. 4... Shadow mask, 5... Envelope, 7... Fluorescent surface, 9... Internal magnetic barrier, 13...・Fixing metal fittings, 14...
Lower end.

Claims (1)

[Scope of utility model registration request] The inside of a color picture tube, in which a plurality of pins are provided on a support of a shadow mask provided in an envelope, and a magnetic barrier body subjected to a blackening treatment is fixed to the support by a fixing fitting through the pins. In the magnetic barrier fixing structure, the fixing fitting has an elastic engagement part in the center that is inserted from the top of the pin and elastically engages with the pin, and an outer periphery of the lower end that contacts the magnetic barrier. An internal magnetic shield for a color picture tube, characterized in that the internal magnetic shield has a curvature portion curved in a direction opposite to that of the magnetic shield.