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:
Dec. 21, 1982
Filed:
Aug. 11, 1980
Applicant:
Inventors:
Kazuo Tanaka, Tokyo, JP;
Ryusho Hirose, Machida, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ; G02B / ;
U.S. Cl.
CPC ...
350429 ; 350427 ;
Abstract
A zoom objective includes four lens groups of which the first and fourth groups are stationary, while the second and third groups are movable independently of each other. Focus adjustment of one of the second and third groups is followed by zooming relative movement of the latter two. To maintain a constant zoom ratio throughout the entire focusing range, the relative movement of the second and third groups is controlled to effect monotonic variation of the magnifying powers of the second and third groups by means of the following formulae as embodied in a microcomputer.