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:
Oct. 13, 1992
Filed:
Dec. 06, 1990
Kazuyoshi Hata, Osaka, JP;
Minolta Camera Co., Ltd., Osaka, JP;
Abstract
The present invention provides a compact zoom lens having a zooming ratio of six (6) to eight (8) and an F-number of 1.4 to 1.6, and comprising from the object side; a first lens unit of a positive refractive power and consisting of, from the object side, a first negative meniscus lens element convex to the object side, a second positive lens element, located at the image side of the first negative meniscus lens element with having an air space therebetween, having a stronger refractive surface on its object side surface; a second lens unit of a negative refractive power and consisting of, from the object side, a third negative lens element having a stronger refractive surface of its image side surface, and a fourth positive lens element, located at the image side of the third negative lens element with having an air space therebetween, said second lens unit including an aspheric surface; a third lens unit of a positive refractive power and consisting of a single positive lens element having an aspheric surface; and a fourth lens unit of a positive refractive power and including a positive lens element and a negative lens element; and the second lens unit being shiftable in the zooming operation and at least one of the first, third and fourth lens unit being also shiftable in the zooming operation.