The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Dec. 23, 1997

Filed:

Dec. 27, 1995
Applicant:
Inventors:

Chang-seob Kim, Suwon, KR;

Seok-bong Son, Suwon, KR;

Sang-kyun Kim, Seoul, KR;

Bong-uk Jeong, Seoul, KR;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J / ; H01J / ; H01K / ;
U.S. Cl.
CPC ...
3133 / ; 313345 ; 3133 / ;
Abstract

A directly heated cathode structure includes a porous pellet impregnated with a cathode material, a first metal member fixed to a surface of the porous pellet, a second metal member welded to the first metal member, and a filament interposed between the first and second metal members. A method for manufacturing a directly heated cathode structure includes manufacturing a porous pellet having a multiplicity of cavities, welding a first metal member to a surface of the porous pellet with a brazing layer, impregnating the cavities of the pellet with an electron radiating material, and welding a second metal member to the first metal member with a filament disposed between the first and second metal members. The useful life of the cathode structure is prolonged since thermions are not emitted through the surface of the pellet covered by the metal member.


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