JPS61206131A - Impregnated cathode - Google Patents

Abstract

PURPOSE:To weld a pellet reliably to a cap or a sleeve by making same or larger number of notches or grooves than the welding points for securing the pellet to the cap or the slave in the outercircumference of the pellet. CONSTITUTION:Notches or grooves of same or larger number than the welding points for securing a pellet to a cap or a slave are made in the outercircumference of the pellet. When the inner diameter of the sleeve or the cap is slightly shorter then the outer diameter of the pellet, the wall face of the sleeve or the cap will deform from the shape constituting a portion of a circle to short linear shape at the notch or the groove made in the outercircumference of the pellet, thus to contact the circular outercircumference except at the notch or the groove tightly against the innercircumferential face of the cap or the sleeve. Consequently, they can be welded easily and reliably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention provides a method for easily and reliably fitting and welding emitter-impregnated pellets into the end of a cap or sleeve.
This invention relates to an impregnated cathode that can be fixed.

[Background of the invention]

In recent years, cathode ray tubes, particularly high-definition tubes, have come to require cathodes that can stably emit a narrow electron beam with extremely high electron density over a long period of time. Ordinary so-called oxide cathodes cannot fully satisfy these requirements, so impregnated cathodes, which have traditionally been used as cathodes for ultrashort wave tubes and other devices that are exposed to intense back bombardment, have been developed.
It has also come to be used as a cathode for cathode ray tubes.

Figure 2(a) shows pellet 2 impregnated with an emitter,
An example of an impregnated cathode for a cathode ray tube that is directly welded and fixed to the sleeve 1 is shown, the upper part shows a plan view, and the lower part shows a side sectional view, and FIG. 2(b) shows a pellet 2 with a cap. 3 shows an example in which the sleeve 1 is welded and stored, and then attached to the sleeve 1. In general, this structure is better than Figure (a
It is easier to manufacture than the structure shown in ).

If it is used for ultra-high-frequency tubes, the number of units produced is not very large, so it can take a considerable amount of man-hours to manufacture, but in the case of cathode ray tubes, the number of units required is extremely large, so it is necessary to ensure that It must be possible to mass produce.

However, in general, if tolerances are set so that a disc-shaped object can always be reliably fitted into a cylindrical body,
Except in extremely miraculous and exceptional cases, there is usually always a gap between the inner circumferential surface of the cylindrical body and the outer circumferential surface of the disc-shaped object.

Currently, both the outer diameter of the pellet 2 and the inner diameter of the sleeve 1 or cap 3 can be manufactured to a tolerance of about ±0.01 m, but as shown in Figure 3, if we decide to weld at three locations, for example. Even if welding is possible at the two welding points 4, a relatively large gap will be created between the sleeve and the pellet at the third point, resulting in poor welding (insufficient adhesive force due to holes 5, etc.). be. Such a device lacks support strength, resulting in, for example, a defective gap dimension with the first grid, or deformation during use, resulting in poor characteristics.

In other respects, the laser welding method is used for this type of welding, but the laser welding method is particularly unsuitable for forming holes when there are gaps between the objects to be welded.

(Object of the Invention) An object of the present invention is to provide an impregnated cathode that does not cause the above-mentioned problems and allows pellets to be reliably welded and fixed to a cap or sleeve at all times during mass production. .

[Summary of the invention]

In order to achieve the above object, in the present invention, the outer peripheral surface of the pellet is provided with notches or grooves in the same number or more than the number of welding points for fixing the pellet to the cap or sleeve, and the pellet is capped. Alternatively, when the pellet is fitted into the end of the sleeve, the outer peripheral surface of the pellet other than the notch or groove is in close contact with the inner peripheral surface of the end of the cap or sleeve. This is because when the inner diameter of the sleeve or cap is slightly smaller than the outer diameter of the pellet, the wall surface of the sleeve or cap has no pellets inside that prevents deformation at the notch or groove provided on the pellet's outer periphery. , it deforms from a shape that forms part of a circle to a short shape that is close to a straight line, and as a result of this deformation, the length of the portion of the inner circumferential surface of the cap or sleeve that is in contact with the circular outer circumferential surface of the pellet is substantially increased. Even though the inner diameter of the cap or sleeve was slightly smaller than the outer diameter of the pellet, the pellet could be fitted into the cap or sleeve, and at the same time the circular outer circumferential surface of the pellet other than the notch or groove It comes into close contact with the inner peripheral surface of the sleeve.

[Embodiments of the invention]

FIG. 1(a) is a plan view showing a fitted state of a pellet and a cap according to an embodiment of the present invention, and FIG.
a) It is an enlarged view of the part indicated as A inside. Figure 1(b)
Therefore, at the location where the notch 6 is provided on the outer peripheral surface of the pellet 2, the wall surface of the sleeve 1 is deformed from a part of a circle to a shape close to a straight line, and the length margin created by the deformation is
It can be seen that it has reached the part where the outer peripheral surface of the pellet and the inner peripheral surface of the sleeve are in contact.

〔Effect of the invention〕

As explained above, according to the present invention, fitting the impregnated cathode pellet into the cap or sleeve, welding and fixing the two can be carried out easily and reliably, and the impregnated cathode can be mass-produced. .

[Brief explanation of the drawing]

FIG. 1(a) is a plan view showing a fitted state of a pellet and a sleeve according to an embodiment of the present invention, and FIG. 1(b) is a diagram (A in a7).
Figures 2(a) and 2(b) are diagrams showing examples of conventional impregnated cathodes, and Figure 3 is a diagram explaining the causes of welding defects in conventional impregnated cathodes. be. 1・-・Sleeve, 2・−・Pellet, 3・−
・Cap, 4・−・Welded contact, 5・−・Perforated, 6・−・Notch.

Claims (1)

[Claims] In an impregnated cathode in which a pellet impregnated with an emitter is fitted into a cap or directly into an end of a sleeve and fixed, when the pellet is fitted into the end of the cap or sleeve, it faces the inner circumferential surface thereof. The outer peripheral surface of the pellet is provided with notches or grooves of the same number or more as the number of welding points for fixing the pellet to the cap or sleeve, and when the pellet is fitted to the end of the cap or sleeve, the cutout of the pellet An impregnated cathode characterized in that the outer circumferential surface of a portion other than the notch or groove is in close contact with the inner circumferential surface of the end of the cap or sleeve.