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:
Sep. 20, 1988
Filed:
Apr. 25, 1986
Applicant:
Inventor:
Kuniharu Osakabe, Mobara, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
315382 ; 315 14 ; 313414 ;
Abstract
At least one of the focusing electrodes stages disposed between an acceleration electrodes stage and a rear focusing electrodes stage is constituted by first and second grid electrodes, confronting portions thereof having asymmetrical construction with respect to an electron beam axis. A constant focusing voltage is applied to the first grid electrode, and a dynamic focusing voltage gradually increasing or decreasing from the constant focusing voltage as the degree of beam deflection increases is applied to the second grid electrode.