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. 27, 1997
Filed:
Sep. 15, 1995
Toshihiko Ueda, Toyokawa, JP;
Minolta Co., Ltd., Osaka, JP;
Abstract
A variable magnification lens system of the invention has from the object side a positive first lens unit and a negative second lens unit. The first lens unit includes a negative first lens element and a positive second lens element. The negative second lens unit includes a positive third lens element and a negative fourth lens element. At variable magnification from an equal magnification (1:1) state to an enlargement state, the overall lens system moves while the spacing between the two lens units is increased, and the distance between the object and the image remains constant. The object side surface of the first lens element and the image side surface of the fourth lens element are concave. Aspherical surfaces are provided on both surfaces of the first lens element and the image side surface of the third lens unit. The focal length of the first lens element and fourth lens element are suitable stipulated by a condition.