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:
Mar. 23, 1976
Filed:
Oct. 07, 1974
Applicant:
Inventors:
Assignee:
Hitachi, Ltd., , JA;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
316 26 ; 148 203 ;
Abstract
A stabilizing method is provided wherein a field emission cathode is subject to heat treatment of 2,000.degree.C. to 3,000.degree.C. in a hydrogen gas atmosphere of 1 .times. 10.sup..sup.-9 Torr to 5 .times. 10.sup..sup.-7 Torr and hereinafter an electric field in excess of 10.sup.7 volt/cm is applied to the cathode, whereby the emitted electron beam current from the cathode can be maintained constant for a long time.