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:
Jun. 22, 1999
Filed:
Apr. 26, 1993
Kazuyuki Kondo, Kawasaki, JP;
Hidetoshi Tanaka, Yokohama, JP;
Kazushi Kitajima, Kawasaki, JP;
Yukio Takemura, Kawasaki, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An image pickup apparatus has an adjusting mechanism for zoom lens unit so that the apparatus is made compactly. The zoom lens unit is constituted by a first group having a negative refracting power, a second group having a positive refracting power, a stop, a third group having a positive refracting power and a fourth group having a negative refracting power which are sequentially arranged from the object side to be substantially symmetrical about the stop. An image forming magnification is changed by moving whole system and moving the second and third groups on an optical axis thereof while a distance between an object and the image is kept constant. Image formation characteristics of the overall lens system are adjusted by moving and/or decentering the first group and/or the fourth group on/from the optical axis.