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:
May. 14, 1991
Filed:
Jan. 23, 1989
Applicant:
Inventors:
George V Miram, Atherton, CA (US);
Yosuke M Mizuhara, Palo Alto, CA (US);
Assignee:
Varian Associates, Inc., Palo Alto, CA (US);
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
313 37 ; 313270 ; 3133 / ; 445 35 ; 445 46 ; 445 51 ;
Abstract
In order to bring a high power vacuum tube to full power in a few seconds, it is necessary to heat the cathode quickly to 1100.degree. C. In large tubes, prior art structures cannot be simply enlarged. A novel cathode structure in which the heater element is anisotropic pyrolytic graphite coated with anisotropic pyrolytic boron nitride for insulation and then sintered to the cathode avoids these problems.