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:
May. 21, 1985
Filed:
Oct. 13, 1983
Muneharu Sugiura, Kanagawa, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An optical system of zoom lens has four lens groups or, from front to rear, a first lens group of positive power for focusing, a second lens group of negative power for variation of the image magnification, a third lens group of negative power for image shift compensation, and a fourth lens group of positive power for forming an image of an object. The fourth lens group has two component lens group, i.e., from front to rear, a first component lens group and a second component lens group. The fourth lens group's first component lens group has five lenses, namely, from front to rear, a biconvex first lens with a strong curvature at its rear surface, a biconvex second lens with its front surface of strong curvature, a third lens of negative power with a strong curvature at its front surface, a fourth lens of positive power with a strong curvature at its front surface, and a fifth lens of positive power with its front surface of strong curvature. The fourth lens group's second component lens group has three lenses, namely, from front to rear, a first lens of negative power with a strong curvature at its rear surface, a biconvex second lens with its rear surface having strong curvature and a biconvex third lens with a strong curvature at its front surface.