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:
Aug. 23, 1983
Filed:
Jan. 15, 1981
Applicant:
Inventors:
Assignees:
Nippon Telegraph & Telephone Public Corporation, Tokyo, JP;
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
2503 / ;
Abstract
An electron lens system wherein at least two coils are arranged in the vicinity of an electron-optical lens and are excited in directions opposite to each other, thereby making it possible to adjust the focal distance of the lens without including a rotation attributed to the electron-optical lens in an electron beam which passes through the lens.