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. 08, 1992
Filed:
Jun. 18, 1991
Hitoshi Mukaiya, Toda, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A zoom lens comprising a first lens group having a positive refractive power; a second lens group having a negative refractive power that moves for zooming; a third lens group movable to correct image surface movement; and a fourth lens group stationary during zooming. The fourth lens group consists of six lenses. The first lens reduces divergence of a light beam. Further, if the overall focal length of the system at the wideangle end is F.sub.W ; the focal length of the second lens group is F.sub.2 ; the focal length of the combination of the second to sixth lenses is F.sub.42 ; and the focal length of the combination of the second to fourth lenses is F.sub.A, then the conditions: ##EQU1## are satisfied.