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. 15, 1998
Filed:
Sep. 09, 1996
Applicant:
Inventors:
Sachio Koizumi, Mobara, JP;
Toshifumi Komiya, Mobara, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
3133 / ; 3133 / ; 313337 ;
Abstract
A cathode for an electron tube has an electron emissive material layer on the surface of a cathode base metal. The electron emissive material layer has a three-layer structure composed of a first layer made of an alkaline earth metal oxide which is formed on the surface of the cathode base metal, a second layer which is an alkaline earth metal oxide layer in which a rare earth metal oxide is dispersed, which is formed on the surface of the first layer, and a third layer made of an alkaline earth metal oxide which is formed on the surface of the second layer.