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:
Apr. 20, 1976
Filed:
Aug. 26, 1974
Applicant:
Inventors:
Yoshiyasu Harada, Akishima, JA;
Teruo Someya, Tokyo, JA;
Assignee:
Nihon Denshi Kabushiki Kaisha, Tokyo, JA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
2503 / ; 250397 ;
Abstract
An electron lens system comprising a plurality of quadrupole elements, a plurality of octupole elements for correcting the spherical aberrations of said plurality of quadrupole elements, and an axially symmetric lens, arranged at the inlet or outlet side of said quadrupole and octupole elements for varying the focal length of said lens system so that the excitation currents of said plurality of quadrupole elements remain fixed.