JPH0676763A - Explosion-proof band for color cathode-ray tube - Google Patents

Abstract

PURPOSE:To prevent crack and the like of a panel by improving the shape of an explosion-proof band for color cathode-ray tube. CONSTITUTION:An explosion-proof band 10 is fitted in the side surface of a panel 1 of a color cathode-ray tube, and the mechanical strength of the panel is increased by adding a fixed level of fastening force by the band. An elliptical recess 14 is provided so that the protruded shape of a bat welding part 12 of the explosion-proof band 10 is not brought into direct contact with the side surface of the panel 1. Since there is no possibility of causing any crack, more sufficient and uniform fastening force can be added compared to the conventional case, and the explosion-proof effect is thus improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an explosion-proof band for color cathode ray tubes. More specifically, it relates to the shape of the butt weld of the explosion-proof band.

[0002]

2. Description of the Related Art First, in order to clarify the background of the present invention, a general structure of a conventional color cathode ray tube will be briefly described with reference to FIG. As shown in the figure, the color cathode ray tube is constructed by using a tube in which the panel 1 and the funnel 2 are integrated by a glass seal 3. An electron gun 5 is housed in the neck portion 4 of the funnel 2. A predetermined drive voltage is supplied to the electron gun 5 via the stem 6. A deflection coil 7 is attached to the shoulder of the funnel 2 and deflects and scans the electron beam 8 emitted from the electron gun 5. The inner surface of the panel 1 is coated with a phosphor and receives an electron beam 8 to display an image. In the case of a color cathode ray tube, an aperture grill (mask) 9 is attached inside the panel 1. An explosion-proof band 10 is attached along the side surface of the panel 1.

FIG. 5 shows the external shape of a color CRT. The explosion-proof band 10 is mounted so as to tighten the side surface of the panel 1, and even pressure is applied to the periphery to reinforce the mechanical strength of the panel. That is, it is used to prevent the occurrence of implosion accompanied by scattering of glass fragments such as when the glass tube evacuated to high vacuum is damaged by external force or the like. Supports 11 are attached to the four corners of the explosion-proof band 10, through which the color CRT is held and fixed to a casing (not shown).

[0004]

FIG. 6 is a perspective view showing the shape of a conventional explosion-proof band 10. However, the support tool is not shown. The explosion-proof band 10 is formed by butt welding butt members at both ends. Usually, welding residue and the like remain in the butt weld portion 12 and the shape thereof changes. Therefore, the convex portion 13 protruding from the surface of the band 10 is formed. In particular, the convex portion formed on the inner side surface of the explosion-proof band 10 abuts on the outer side surface of the panel, and if a tightening force is applied, cracks or the like may occur. Therefore, there has been a problem that a sufficient tightening force cannot be applied to the conventional panel. As a countermeasure against this, for example, Japanese Patent Laid-Open No. 62-62
As disclosed in Japanese Patent No. 5533, a means of interposing a thick tape, a glass fiber tape or the like in the contact portion has been taken, but there is a problem that the cost becomes high and the work becomes complicated.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, the present invention provides a band welded shape capable of enhancing the explosion-proof effect by applying a sufficient and uniform tightening force to a panel of a color cathode ray tube. The purpose is to provide. The following measures have been taken in order to achieve this object. That is, the explosion-proof band mounted on the panel side surface of the color cathode ray tube is characterized in that a recess is provided so that the convex shape portion of the butt weld portion does not directly contact the panel side surface. This recess has a substantially elliptical shape.

[0006]

In the present invention, an elliptical recess is provided in the region including the convex portion of the butt weld. The depth of this recess is set to be larger than the height of the convex portion, and the convex portion is depressed inside the recess. Therefore, when the explosion-proof band is attached to the panel side surface of the color cathode ray tube, the convex portions do not come into contact with each other, so that a uniform tightening force can be applied.
In particular, by providing the recess at a position aligned with the mold match line (MML) of the front panel, it is possible to effectively suppress the occurrence of cracks and the like. This MML is
It is a built-up portion of glass that is formed at the joint between the bottom portion and the shell portion during the front panel molding process, and usually has a height of about 0.5 mm. Further, the elliptical shape has a function of dispersing the tensile stress of the explosion-proof band itself generated when the side surface of the panel is tightened, and can also prevent the shape deformation.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory view showing a preferred specific example of the explosion-proof band for color cathode ray tubes according to the present invention.
(A) is a perspective view showing the overall shape of the explosion-proof band. Portions common to the conventional band structure shown in FIGS. 4 to 6 are given common reference numerals to facilitate understanding. As a feature of the present invention, the butt weld 12 of the band 10 is provided with a substantially elliptical recess 14 on the inner surface.

FIG. 1B is an enlarged perspective view of a partial cross section showing the shape of the welded portion 12. The recess 14 is formed during the manufacturing process of the explosion-proof band. That is, in the process of butt welding both sides of the band to process the band, a process step of adding an elliptical recess to the region including the convex shape of the welded portion generated by the butt welding is added.

FIG. 1C is a schematic view showing a positional relationship when the explosion-proof band 10 is attached to the side surface of the panel 1 of the color CRT. The recess 14 is provided at a position just aligned with the MML of the panel 1. The amount of depression of the recess 14 is made deeper than the height of the convex shape of the welded portion 12, processed so as not to project from the inner side surface of the band 10, and formed into a substantially elliptical shape. This elliptical shape prevents the welded convex shape from directly contacting the MML by dispersing tensile stress of the band 10 itself generated after the band 10 tightens the side surface of the panel 1 and preventing deformation. By providing the elliptical recess 14 in the butt weld portion, even if the height of the convex portion of the weld portion varies, it does not come into contact with the panel side face MML, and the occurrence of cracks can be prevented. Even if a protective tape is interposed, it is not necessary to use a conventional thick tape or a glass fiber tape, and a polyester tape can be used sufficiently. Further, it is not necessary to perform complicated notch polishing or the like on the convex portion of the butt welded portion, unlike the conventional case. The side surface of the panel can be tightened uniformly with sufficient force, and a stable explosion-proof effect can be obtained.

FIG. 2 is a schematic view showing another embodiment of the explosion-proof band for color cathode ray tubes according to the present invention. In this example, the band-shaped groove 14 is previously formed along the longitudinal direction of the explosion-proof band 10.
Has been extended. The band-shaped groove 14 may have an arc-shaped cross section as shown in the drawing, or may have a rectangular shape instead.

FIG. 3 shows a state in which butt welding is performed to join both ends of the band 10 shown in FIG. The band-shaped grooves 14 formed at both ends of the band 10 are connected to each other to form a recess. The convex portion of the butt weld located in the recess is depressed from the inner surface of the band, and there is no possibility of directly contacting when mounted on the panel side surface.

[0012]

As described above, according to the present invention, in the explosion-proof band for color cathode ray tubes, for example, an elliptical recess is formed so as to include the convex portion of the butt welded portion. With this structure, when the explosion-proof band is attached to the side of the panel, the convex parts do not directly contact, so there is no risk of cracks, etc. Is significantly improved.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an explosion-proof band for color cathode ray tubes according to the present invention.

FIG. 2 is a schematic view showing another embodiment of the explosion-proof band for color cathode ray tubes according to the present invention.

3 is a schematic perspective view showing a shape of a butt welded portion of the explosion-proof band shown in FIG.

FIG. 4 is a sectional view showing a general structure of a conventional color CRT.

FIG. 5 is a perspective view showing an appearance of a conventional color CRT.

FIG. 6 is a perspective view showing the shape of a conventional explosion-proof band.

[Explanation of symbols]

 1 Panel 2 Funnel 3 Glass Seal 4 Neck 5 Electron Gun 6 Stem 7 Deflection Coil 9 Aperture Grill (Mask) 10 Explosion-Proof Band 11 Supporting Tool 12 Butt Weld 13 Convex Shaped 14 Depression

Claims (3)

[Claims] 1. An explosion-proof band for a color CRT mounted on a panel side of a color CRT, characterized in that a recess is provided so that a convex portion of the butt weld does not directly contact the side of the panel. Explosion-proof band. 2. The explosion-proof band for a color cathode ray tube, wherein the recess has a substantially elliptical shape. 3. The explosion-proof band for a color cathode ray tube, wherein the recess is a band-shaped groove extending along the longitudinal direction of the band.