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:
Jan. 02, 1979
Filed:
Oct. 29, 1976
Applicant:
Inventors:
Keiichi Sakaguchi, Yokohama, JP;
Atsushi Someya, Machida, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G02B / ;
U.S. Cl.
CPC ...
350184 ; 350187 ;
Abstract
A zoom optical system is composed of a positive focusing lens group, a negative variating lens group, a negative compensating lens group and a positive rear fixed lens group. A rotating grooved cam moves the variating lens group and the compensating lens group in a given relation to each other along the optical axis in the normal focusing range. The focusing lens group is moved along the optical axis normal range for focusing. The variating lens group is kept stationary on the optical axis while the compensating lens group is moved along the optical axis during close-range focusing.