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:
Jul. 01, 2014
Filed:
Jan. 19, 2011
Boklae Cho, Hitachinaka, JP;
Shigeru Kokubo, Mito, JP;
Hisaya Murakoshi, Tokyo, JP;
Hisao Nitta, Naka, JP;
Boklae Cho, Hitachinaka, JP;
Shigeru Kokubo, Mito, JP;
Hisaya Murakoshi, Tokyo, JP;
Hisao Nitta, Naka, JP;
Hitachi High-Technologies Corporation, Tokyo, JP;
Abstract
The disclosed charged particle beam apparatus includes a field-emission electron source including <310> single crystal of tungsten; a vacuum chamber having the electron source therein; an exhausting system for exhausting the vacuum chamber; a filament connected to the electron source to let flow a current through the electron source and thereby heat the electron source; a power supply for letting a current flow through the filament; an ammeter for measuring a total current emitted from the electron source; and a controlling unit for exercising control to cause the power supply to let a current flow through the filament when the total current measured periodically has become a predetermined ratio or less as compared with a total current from the electron source found immediately after first electron beam emission, or a total current from the electron beam found immediately after a current is let flow through the filament.