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. 30, 1999
Filed:
Dec. 20, 1996
Nobuya Seko, Tokyo, JP;
NEC Corporation, , JP;
Abstract
There is provided a field-emission type cold cathode including (a) a substrate at least a surface of which has electrical conductivity, (b) an insulating layer formed on the substrate, (c) an electrically conductive gate electrode formed on the insulating layer, (d) an almost conical, sharp-pointed emitter electrode disposed in a hole formed through the gate electrode and insulating layer, (e) a focusing electrode formed on the insulating layer so that the focusing electrode is located in the same plane as the gate electrode and surrounds the gate electrode, and (f) a feeder line formed in the same plane as the gate electrode. The feeder line extends from the gate electrode into the focusing electrode and being shaped complementarily with the focusing electrode so that the focusing electrode is present at every radial directions as viewed from a center of the emitter electrode. The present invention provides an electron source which has small divergence and has high axis-symmetry, and which can be fabricated by conventional field-emission type cold cathode fabrication methods having no focusing electrodes. Hence, the present invention makes it possible to provide a high-quality cathode at lower cost suitable for an electron source for an electronic tube and an electron beam emitter.