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. 12, 1983
Filed:
Sep. 03, 1981
Applicant:
Inventor:
Setsuo Norioka, Akishimashi, JP;
Assignee:
JEOL Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G21K / ; G21K / ; H01J / ;
U.S. Cl.
CPC ...
2503 / ; 2503 / ; 250310 ; 250311 ;
Abstract
The relation between the focusing distance (D) of the objective lens and the excitation current (I) of the objective lens is stored in a data memory. The initial focusing distance (D.sub.o) corresponding to the optimum excitation current is determined as a result of the focusing adjustment operation. Thereafter, the change (.DELTA.D) in the focusing distance due to the specimen shift along the optical axis of the objective lens is detected. The magnitude of the excitation current corresponding to the focusing distance (D.sub.o +.alpha.D) is read from said memory and a current of that magnitude is supplied to the objective lens.