JPH0251822A - Impregnated type cathode structure - Google Patents

Abstract

PURPOSE:To firmly connect both members and improve the heat conduction between a cathode substrate and a cathode sleeve by providing groove sections on the outer face of the closed end of the cathode sleeve or the bottom face of the cathode substrate, arranging metal fine wires in the groove sections, and connecting both members. CONSTITUTION:Groove sections 9 are provided on the outer face of the closed end of a cathode sleeve 8, metal fine wires 7 are arranged in the groove sections 9, a cathode substrate 1 is brought into close contact with the cathode sleeve 8, peripheries of both members 1 and 8 are connected by soldering or the like. The metal fine wires 7 are connected to eyelets, the cathode sleeve 8 is suspended and held. The outer face of the closed end of the cathode sleeve and the bottom face of the cathode substrate are closely stuck, thus the heat conduction between both members is improved, stable electron emission characteristic is obtained, both members can be connected with sufficient strength.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an impregnated cathode structure, and more particularly to a bonding structure between a cathode substrate and a cathode sleeve.

[Conventional technology]

The impregnated cathode is used in television picture tubes, image pickup tubes, observation tubes for oscilloscopes, etc. as a cathode capable of obtaining a high tRVIj degree. The cathode of type C is made by impregnating an electron-emitting substance into a porous base made of a high-melting point metal, and heating it with a heater to emit electrons at a high current density. The cathode is 1000
Since it is necessary to maintain the temperature at a high temperature of around 30°F, efforts have been made to create a structure that minimizes heat loss.

3 and 4 show the structure of a conventional impregnated cathode structure, in which a barium-calcium (Ba- Ca) is a cathode substrate impregnated with an electron-emitting substance such as aluminate, and 3 is tantalum ('')
The cathode sleeve is made of a high-melting point metal such as molybdenum (MO) and is closed at one end, and a heater 4 is built into the cathode sleeve.

Reference numeral 4 denotes a heater made of a tungsten (W) core wire coated with alumina, which heats the cathode substrate to about 1000°C. Reference numeral 5 denotes a heat reflecting tube which reflects heat radiation radiated from the outer peripheral surface of the heated cathode sleeve 3 and is designed to reduce heat loss due to heat radiation as much as possible. 6
is an eyelet that holds the heat reflecting cylinder 5. Also,
The cathode sleeve 3 is lifted using two thin metal wires (approximately 50 μm in diameter) 7 made of high melting point and high toughness such as tungsten-Vnium (W-Re), which are joined to the eyelets 6. To hold one piece without contacting the member 1
In this way, heat loss due to thermal conduction is minimized.

Regarding such an impregnated cathode structure pot, for example, Japanese Patent Application Laid-Open No. 56-168316 and Japanese Patent Application Laid-Open No. 61-2883
No. 39, etc. (this is disclosed.

[Problem to be solved by the invention]

However, according to the above-mentioned conventional technology, as shown in FIG.
Since thin metal wires with a diameter of about 50 μm are arranged in a cross shape between the top surface of , 3, and there was a fear that stable electron emission characteristics could not be obtained.

Therefore, it is possible to raise the temperature of the heater 4 to a higher temperature to increase the heat transfer to the power bond base. There is a risk of reducing the strength and shortening the life of the cathode structure.

Also, due to the gap created between both members 1 and 3, both members 1 and 3
, 3 are usually joined by spot welding, but there is a possibility that sufficient welding strength may not be obtained.

In view of the above conventional problems, an object of the present invention is to provide good heat conduction between the cathode base and the cathode sleeve, and
It is an object of the present invention to provide an impregnated cathode structure capable of bonding the above-mentioned two members together with sufficient strength.

[Means to solve the problem]

The above purpose is to provide a heater, a cathode sleeve with one end closed that houses the heater, a cand attached to the outer surface of the closed end of the cathode sleeve, a base body, and an outer peripheral side of the cathode sleeve facing this. , an impregnated cathode assembly comprising spaced apart heat reflecting cylinders and holding the cut sleeve suspended by a thin metal wire; A groove is provided on the bottom of the
This is achieved by arranging the above-mentioned thin metal wire in the groove 11f and creating a structure in which both members are joined.

[Effect]

According to the above means, the outer surface of the closed end of the cathode sleeve and the bottom surface of the cathode base are in close contact with each other, so that the heat conduction between the two members is good, and stable electron emission characteristics are obtained.
Moreover, both members can be joined with sufficient strength.

〔Example〕

Hereinafter, one embodiment of the invention will be described with reference to FIGS. 1 and 2. Components that are the same as those in FIG. 3 are given the same reference numerals.

In Fig. 1, ■ is a cathode in which a porous substrate made of a high-melting point metal such as tungsten (W) or molybdenum (Mo) is impregnated with an electron-emitting substance such as barium-calcium (Ba-Ca) aluminate. The base body is a cathode sleeve 8 made of a high-melting point metal such as tantalum (Ta) or molybdenum (MO), which is closed at one end, and has a heater 4 built therein. Up to this point, the steps are the same as in the prior art, but in the present invention, a groove portion 9 is provided on the outer surface of the closed end of the cathode sleeve 8, a thin metal wire 7 is provided in this iJ portion 9, and the cathode base 1 is placed on the groove portion 9. This feature is that the peripheral edges of both members 1 and 80 are joined by welding or the like. Then, in the same way as above, the eyelet 6 (not shown) is connected to the thin line 7.
The cathode sleeve 8 is lifted up and held. By rubbing such a configuration I, it is possible to bring the two members 1, 8 described above into close contact and join them.

Another embodiment of the invention is shown in FIG. In this embodiment, a groove 11 is provided on the bottom surface of the cathode base 10, a thin metal wire 7 is placed in the groove 11, and this is brought into close contact with the outer surface of the closed end of the cathode sleeve 3, and both members 3. The peripheral edges of 10 are joined by welding or the like.

Additionally, grooves are provided on the bottom surface of the cathode base and on the outer surface of the closed end of the cathode sleeve so as to face each other.
The two members may be brought into close contact with each other and joined together by disposing a thin metal wire.

〔Effect of the invention〕

As a result of the above-described present invention, heat transfer between the cathode sleeve and the cathode substrate is improved, stable radiation characteristics are obtained, and the two members are bonded together by a mechanical bond, resulting in a highly reliable impregnated cathode. A structure is obtained.

[Brief explanation of the drawing]

FIGS. 1 and 2 are perspective views of the main parts of a cathode assembly (one embodiment of the present invention), FIG. It is a perspective view of essential parts. 1... Cathode, 1, 3... Cathode sleeve 1, To... Heater, 5... Heat reflecting tube, 7
...Thin metal wire, 8...Cathode sleeve,
9...#1 part, 10... cathode substrate,
11...Groove. 7:'KA axis 11: Streaming

Claims (1)

[Claims] 1. A heater, a cathode sleeve with one end closed containing the heater, a cathode base attached to the outer surface of the closed end of the cathode sleeve, and a cathode base provided on the outer circumferential side of the cathode sleeve, facing and spaced apart from the cathode sleeve. In an impregnated cathode structure having a heat reflecting tube and holding the cathode sleeve suspended by a thin metal wire, a groove is provided on the outer surface of the closed end of the cathode sleeve and/or on the bottom surface of the cathode base, and a groove is provided in the groove. An impregnated cathode assembly characterized in that the thin metal wire is disposed, the closed end outer surface of the cathode sleeve is brought into close contact with the bottom surface of the cathode base, and these two members are joined.