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:
Dec. 19, 2006
Filed:
Feb. 17, 2005
Tadashi Fujieda, Mito, JP;
Kishio Hidaka, Hitachiota, JP;
Mitsuo Hayashibara, Hitachinaka, JP;
Hitachi High-Technologies Corporation, Tokyo, JP;
Abstract
A field-emission electron gun includes a field-emission cathode including a single fiber-like carbon substance and an electrically-conductive substrate for supporting the substance, an extractor for field-emitting electrons, an accelerating electrode for accelerating the electrons, an extracting power-supply for applying extracting voltage to the extractor, an accelerating power-supply for applying accelerating voltage to the accelerating electrode, and a unit for detecting and monitoring a part of emission current. In this field-emission electron gun, if emission-variation amount has become larger than a predetermined value, the extracting voltage is automatically boosted for a constant length of time, thereby increasing the emission current up to a predetermined value. Further, extracting voltage at the time of boosting the extracting voltage, voltage-boosting time, and the emission current are recorded, then being feed-backed to voltage-boosting conditions for the next-time extracting voltage. Moreover, the accelerating voltage is varied in correspondence with the voltage-boosting of the extracting voltage.