JPH0234138B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention prevents the implosion of the bulb by applying an adhesive layer to the maximum outer diameter of the bulb of an internally evacuated cathode ray tube, and firmly inserting a metal band around the outer periphery of the adhesive layer. This invention relates to an explosion-proof cathode ray tube with a structure that prevents explosions.

As shown in FIG. 1, an adhesive layer 2 of adhesive tape or resin is formed on the outer periphery of the maximum diameter part of a cathode ray tube bulb 1 whose interior is evacuated to a high vacuum.
A heated and expanded metal strap 3 is fitted around the outer periphery, and is then cooled and contracted to firmly strap the maximum outer diameter of the valve 1 to prevent the valve from imploding. .

Conventionally, the metal strap 3 has been used by cutting and bending a single plate as shown in the figure, but the cut edge 3a of the strap tends to have burrs and curls, making it difficult to handle and improve appearance. Not good. In addition, the explosion-proof effect of the metal strap 3 is considered to be proportional to its cross-sectional area, but if the number of metal straps 3 is increased to increase the cross-sectional area, the material cost of the strap 3 increases and When fitting, the valve side surface 3b of the bandage 3 does not conform to the valve 1, and the effective area for pressing the valve 1 through the adhesive layer 2 decreases, making it impossible to obtain a sufficient explosion-proof effect. . Furthermore, as shown in FIG. 2, the metal strap 3 has a structure in which the joints at both ends are overlap welded, but in such a structure, a large step is created at the joint, and the valve 1 A large gap 4 is created between the metal strap 3 and the explosion-proof effect is reduced, and
When inserting the metal bandage 3 into the valve 1, the step 5 catches the adhesive layer 2, making the insertion operation difficult. In addition, the tension of the metal strap 3 applies stress that presses the valve 1 to the end 3c of the metal strap 3 that is in contact with the valve 1, which causes the valve to crack.

Further, FIG. 3 shows that the bulb 1 and the adhesive layer 2 are formed in the same manner as shown in FIG. I am doing it. While the cross-sectional area of the metal bandage is large and has sufficient strength, the double structure allows good compatibility with the valve 1 and the adhesive layer 2, and the folded portion 12 is continuously rounded. As a result, it is significantly superior in terms of appearance and workability compared to the conventional single plate with edges, but the difference in level that occurs at the joint shown in Figure 2 is compared to the case of a single plate. 2, and the drawbacks described in FIG. 2 become even more noticeable.

The present invention was developed in view of the above-mentioned drawbacks of the prior art, and has a good appearance and handleability without causing burrs or curls at the end, and has sufficient compressive strength and good conformability to the valve. It is an object of the present invention to provide an explosion-proof cathode ray tube which exhibits an explosion-proof effect, is easy to insert and fit, can reduce material costs, and does not cause valve cracks.

Hereinafter, the present invention will be explained with reference to illustrated embodiments.

4 and 5 show embodiments of the present invention. In the case of FIG. 4, the folded part 2 of the metal bandage 20 is
1 is curved, and a cavity 22 is provided inside the double structure. Similarly, in the case of FIG. 5, a cavity 32 is formed in the double structure part, while the part of the metal bandage 30 on the valve 1 side is the outer folded part 31.
formed shorter. As shown in FIG.
3 are stacked on top of each other and then compressed and shaped by pressing etc., and the cavities 22 and 32 are removed, so the joint part 23 has no raised part compared to other parts and is flat. In addition, since the gap between the valve 1 and the metal straps 20, 30 is extremely small, the explosion-proof effect can be significantly enhanced. In addition, since the gap 24 is lowered and the cavities 22 and 32 are provided near the joint 23, the metal tension band 2
The stress in the direction of the valve 1 due to the tension of 0.0.30 is alleviated by the folded portions 21, 31, and the local stress pressing the valve 1 due to the end portion 25 is significantly reduced and valve cracking is prevented.

Note that the cavities 22 and 32 are at least connected to the joint portion 23.
A sufficient effect can be obtained if it is placed near the .

As is clear from the above description, according to the explosion-proof cathode ray tube of the present invention, the metal strap has a double structure with a folded part, and the joint part is overlapped and welded and compressed into a flat shape. As a result, the appearance and handling properties are good, the tension material can be made thinner, the cost of the tension material can be reduced, and the tension material conforms well to the valve and the adhesive layer.
It is low cost, exhibits excellent explosion-proofing effects, and has the advantage of not causing valve cracks.

[Brief explanation of drawings]

Figure 1 is a cross-sectional explanatory diagram of the main parts of a conventional explosion-proof cathode ray tube, Figure 2 is a front explanatory diagram of the vicinity of the joint of the metal strap in Figure 1, and Figure 3 is an explanatory diagram of another conventional explosion-proof cathode ray tube. FIG. 4 and FIG. 5 are cross-sectional explanatory diagrams of essential parts showing embodiments of the present invention, respectively, and FIG. 6 is a front view of the vicinity of the joint of the metal bandage in FIGS. 4 and 5. It is an explanatory diagram. 10,20,30...metal bandage, 11,21,
31...Folded portion, 15, 22, 32...Cavity, 23...Joint portion.

Claims (1)

[Claims] 1. By applying an adhesive layer to the maximum outer diameter of the bulb of a cathode ray tube, and firmly inserting a metal strap having a welded joint on both ends of the strip around the outer periphery of the adhesive layer, the bulb can be sealed. In an explosion-proof cathode ray tube having a structure to prevent implosion, a part or the whole of the metal strap has a double structure with a folded part, and the double structure part has a cavity at least near the joint part. , and the joint portion is overlap welded and compressed into a flat shape.