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. 25, 1990
Filed:
Feb. 26, 1990
Toshihiko Ueda, Osaka, JP;
Minolta Camera Kabushiki Kaisha, Osaka, JP;
Abstract
A zoom lens system comprising, in order from an enlargement side, a first lens group of a negative power, a second lens group of a positive power and a third lens group of a negative power. The first lens group is fixed during a zooming operation and includes, in order from the enlargement side, a positive lens element, a negative lens element and an aperture stop. The second lens group is movable toward a reduction side during a zooming operation and includes, in order from the enlargement side, a biconvex lens element, a negative meniscus lens element having a concave surface directed to the enlargement side, a positive lens element, a biconcave lens element and a biconvex lens element. The third lens group is also movable toward the reduction side during a zooming operation and includes, in order from the enlargement side, a biconcave lens element and a positive lens element.