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:
Jan. 31, 2006
Filed:
Jun. 23, 2004
Yoshikiyo Yui, Tochigi, JP;
Hiroya Ohta, Kodaira, JP;
Yoshikiyo Yui, Tochigi, JP;
Hiroya Ohta, Kodaira, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Hitachi High-Technologies Corp., Tokyo, JP;
Abstract
An electron gun is composed of a hemispherical cathode () and a second bias electrode () having apertures () along an optical axis of an electron beam fired from the electron gun, a first bias electrode () and an anode (), arranged in that order, as well as a controller for variably controlling an electric potential applied to the first and second bias electrodes. The controller, for example, holds the sum of the electric potentials of the first and second bias electrodes relative to the cathode () substantially constant. Further, by adding one or more third bias electrode(s) () between the first and second bias electrodes () as necessary, the intensity of the electron beam discharged from the high-intensity, high-emittance electron gun can be adjusted without affecting the current density angular distribution.