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. 17, 2002
Filed:
Sep. 25, 2000
Shunji Tsuida, Tokyo, JP;
NEC Corporation, , JP;
Abstract
A cold-cathode electron gun includes a cold cathode, a conical Wehnelt electrode, and an undercut. The cold cathode has an emitter formed on a substrate to emit electrons,. a gate electrode formed on the substrate through a first insulating film so as to surround a distal end of the emitter, and a focusing electrode formed on the gate electrode through a second insulating film to correspond to the gate electrode. The conical Wehnelt electrode connects the focusing electrode to a first external power supply. The Wehnelt electrode has an opening, at its conical distal end, that comes into with the cold cathode to surround an emitter region including the emitter, gate electrode, and focusing electrode. The undercut is formed in a portion of the Wehnelt electrode which is to come into contact with the focusing electrode to correspond to the gate electrode, thereby forming a non-contact portion.