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:
Nov. 09, 1993
Filed:
Apr. 02, 1992
Hironori Shibata, Tokyo, JP;
Shinichi Mihara, Tokyo, JP;
Olympus Optical Co., Ltd., Tokyo, JP;
Abstract
The present invention relates to a small zoom lens system for electronic still cameras or video cameras, which has a zoom ratio lying in the range of about 2.5-3.2 and an F-number lying in the range of about 2-2.8, comprises as small as 7 or 8 lenses and is reduced in terms of both the total length and the lens diameter, and which is characterized by comprising, in order from the object side, at least a first lens group having a positive refractive power, a second lens group having a negative refractive power, a stop and a third lens group having a positive refractive power, and in that during zooming the first lens group remains fixed while the second and third lens groups are moved along the optical axis, and the following conditions (1) and (2) are satisfied: