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. 12, 1995
Filed:
Jun. 24, 1993
Denki Kagaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A thermal field emission cathode comprises a needle-like electrode of single crystal tungsten having an axis direction of <100> provided with a coating layer of zirconium and oxygen; a heater for heating the needle-like electrode; a suppressor electrode; and a supply source for supplying zirconium and oxygen having zirconium of not less than 3.0.times.10.sup.-6 g and not more than 10.times.10.sup.-6 g by weight to the coating layer disposed on the needle-like electrode in a range between a point apart from a junction of the needle-like electrode and the heater by 200 .mu.m in a direction of a distal end of the needle-like electrode and a plane including an outer surface of the suppressor electrode.