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:
May. 07, 2024
Filed:
May. 21, 2019
Hitachi High-tech Corporation, Tokyo, JP;
Minoru Kaneda, Tokyo, JP;
Hitachi High-Tech Corporation, Tokyo, JP;
Abstract
An electron gun EG in which mixing of secondary electrons is suppressed is provided. The electron gun EG has an electron source, an extraction electrodefor extracting an electron beam Efrom the electron source, and an acceleration electrode for accelerating the extracted electron beam E. The extraction electrodeincludes a diaphragmfor allowing a part of the electron beam Eto pass through, a shieldpositioned above the diaphragmapart from the diaphragm, and a shieldpositioned below the diaphragmapart from the diaphragm. The diaphragmhas an opening OPhaving an opening diameter D, the shieldhas an opening OPhaving an opening diameter Dwhich is greater than the opening diameter D, and the shieldhas an opening OPhaving an opening diameter Dwhich is greater than the opening diameter D