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.
Patent No.:
Date of Patent:
Sep. 26, 2000
Filed:
Nov. 26, 1997
Applicant:
Inventors:
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
3133 / ; 3133 / ; 313311 ; 313341 ;
Abstract
An electron tube cathode comprises a base (1) formed mainly of nickel, an alloy layer (4) disposed on the base (1) and including nickel and tungsten having a grain size smaller than that of the base, and an electron emissive material layer (5) deposited on the alloy layer, and including an oxide (6) of an alkaline-earth metal containing at least barium, and a rare earth metal oxide (7) of 0.01 to 25 weight percent and containing at least one of scandium oxide and yttrium oxide. The cathode has a life characteristics improved compared with the prior art, even if operated with a current density of 3 A/cm.sup.2 or more.