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:
Aug. 08, 1989
Filed:
Nov. 14, 1986
Masatake Kato, Tokyo, JP;
Sadahiko Tsuji, Kanagawa, JP;
Muneharu Sugiura, Tokyo, JP;
Kazuo Tanaka, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A compact zoom lens comprising, from front to rear, a first lens unit of positive power for focusing, a second lens unit of negative power axially movable in one direction when zooming from one end of a range of image magnification to the other, a third lens unit of positive power axially movable in a path convex toward the rear to maintain the constant position of an image surface which shifts with zooming, and a fourth lens unit of positive power for forming an image which remains stationary during zooming, wherein a fixed diaphragm is arranged in a space between the second and third lens units.