JPH0511290U - Impregnated cathode structure - Google Patents

Abstract

(57) [Summary] [Purpose] To increase the heating efficiency of impregnated cathode pellets,
Provided is a highly reliable impregnated cathode structure with extended heater life. The impregnated cathode pellet 7 having a stepped portion 7A with a tip portion having a reduced diameter is projected into an inner cylindrical portion 8 having a stepped portion 8a having a reduced diameter portion. , 8
a An impregnated cathode structure in which the two are closely attached and welded.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to an electron gun for a cathode ray tube, and more particularly to the structure of an impregnated cathode.

[0002]

[Prior Art]

 As shown in FIG. 2, the impregnated cathode structure 6 is conventionally fixed by welding by inserting an impregnated cathode pellet 1 into an inner cylindrical portion 3 to which a bottom plate 2 is connected by welding. The inner tubular portion 3 is welded to the outer tubular portion 4. A heater 5 is inserted into the outer tubular portion 4.

[0003]

[Problems to be solved by the device]

 By the way, in the above-mentioned conventional impregnated cathode structure 6, since the inner tubular portion 3 and the impregnated cathode pellet 1 are welded at the tip of the inner tubular portion 3, the inner tubular portion 3 There was a problem that the contact area of the impregnated cathode pellet 1 was small and the heat of the heater 5 was difficult to be transferred to the impregnated cathode pellet 1.

Therefore, in the present invention, the impregnated cathode pellet and the inner cylindrical portion are shaped so as to increase the adhesion area between the two, and the two are heat-bonded by pressure welding. The purpose is to improve conduction.

[0005]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides an impregnated cathode structure in which impregnated cathode pellets are inserted into a metal tubular portion, and a stepped portion is formed by reducing the diameter of the tip portion. Insert the impregnated cathode pellet with a stepped portion and a stepped portion into the inner cylindrical portion so that the stepped portions are in close contact with each other over a wide area. It is characterized by being welded.

[0006]

[Action]

 According to the above configuration, the contact area between the impregnated cathode pellet and the inner cylindrical portion becomes large, and the heat generated by the heater can be efficiently transferred to the impregnated cathode pellet. As a result, the electric power supplied to the heater can be reduced, the life of the heater can be extended, and a highly reliable impregnated cathode structure can be provided.

[0007]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an impregnated cathode according to an embodiment of the present invention. The same parts as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted. In the figure, 2 is a bottom plate made of a heat-resistant metal such as Mo, 4 is an outer cylindrical portion such as Mo, 5 is a heater, 7 is an impregnated cathode pellet, 7a is a stepped portion with a reduced diameter, 8 is Mo, etc. 8a is a stepped portion having a reduced diameter, and 9 is an impregnated cathode assembly of the present invention.

In the above-described structure, the impregnated cathode pen having the stepped portion 7a is formed by projecting the tip portion into the inner cylindrical portion 8 having the stepped portion 8a whose diameter is reduced and opened. The let 7 is inserted and attached so that the step portions 7a and 8a are in close contact with each other, and the close contact portions are welded together. The electron-emitting portion at the tip of the impregnated cathode pellet 7 is exposed from the reduced diameter opening of the inner cylindrical portion. Here, the inner diameter of the stepped portion 8a of the inner tubular portion 8 is set to be slightly smaller than the outer diameter of the stepped portion 7a of the impregnated cathode pellet 7, and the latter stepped portion 7a is moved to the former stepped portion 8a. When inserted, both step portions 7a and 8a are in a crimped state. Since the impregnated cathode pellet 7 and the inner cylindrical portion 8 adhere to each other at the reduced diameter step portions 7a and 8a, the surface area of the adhered portion increases, and the heat generated from the heater 5 is efficiently generated. There is an advantage that it is transmitted to the pellet 7. As a result, the electric power supplied to the heater for maintaining the operating temperature of the impregnated cathode pellet 7 at a predetermined temperature (eg, 1050 ° C) can be reduced, and the operating temperature of the heater can be reduced, so that the heater life is extended. It is possible to extend and realize a highly reliable impregnated cathode.

The step portion of the present invention includes a reduced diameter portion and an extension portion. Although FIG. 1 shows the case where the diameter is reduced at a right angle, the diameter is not limited to the right angle, and the diameter may be tapered.

[0011]

[Effect of the device]

 As described above, the present invention provides a stepped portion in which the shape of the impregnated cathode pellet and the inner cylindrical portion is reduced, and the impregnated cathode pellet is inserted and attached to the inner cylindrical portion. In addition, the heat transfer from the heater can be improved by making the contact portion welded and fixed.

As a result, the operating temperature of the heater can be lowered, the life of the heater can be extended, and an impregnated cathode with high reliability can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view of an impregnated-type cathode assembly according to an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional impregnated cathode assembly.

[Explanation of symbols]

 7 Impregnated cathode pellet 7a Stepped portion of impregnated cathode pellet 8 Inner cylindrical portion 8a Stepped portion of inner cylindrical portion 9 Impregnated cathode structure

Claims (1)

[Claims for utility model registration] [Claim 1] In an impregnated cathode structure in which impregnated cathode pellets are inserted into a metal inner cylindrical portion, a stepped portion is formed by reducing the diameter of the tip portion. Impregnated type cathode pellets, in which the tip is reduced in diameter and protruded to form a stepped portion, are inserted into the inner cylindrical portion and welded so that the stepped portions are in close contact with each other. Cathode structure.