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:
Sep. 06, 1994
Filed:
Mar. 26, 1993
Toshihiko Ueda, Toyokawa, JP;
Sanae Watanebe, Storrs, CT (US);
Minolta Camera Kabushiki Kaisha, Osaka, JP;
Abstract
A zoom lens system for use in a copying apparatus has first, second and third lens units of negative, positive and negative, respectively. Zooming is performed while the conjugate distance is kept constant by varying the distance between the first and second lens units and the distance between the second and third lens units and varying at a magnification either larger or smaller than unity the distance between the second and third lens elements of the second lens unit. The first lens unit has a lens element strongly concave to the object side. The second lens unit has a positive meniscus lens element, a bi-concave lens element and a bi-convex lens element. The third lens unit has a negative meniscus lens element concave to the image side.