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. 01, 1992
Filed:
Apr. 19, 1990
Tatsuzo Ushiro, Saitama, JP;
Naoya Kaneda, Kanagawa, JP;
Hiroyuki Wada, Kanagawa, JP;
Masahide Hirasawa, Kanagawa, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An optical apparatus comprises a first lens to be used for changing a magnifying power; a second lens to be used for focus adjustment and also for compensation required when the magnifying power is varied; a focus detecting circuit for detecting an in-focus state; a first control circuit for driving the second lens to an in-focus position on the basis of information obtained by the focus detecting circuit; a detecting circuit for detecting the position of the second lens; and a second control circuit for driving the second lens to a normal focus adjustable position after driving the second lens to a reset position for the purpose of enabling the detecting circuit to perform a detecting action. The second control circuit is arranged to drive the second lens from the reset position to the focus adjustable position at a higher speed than the driving speed set by the first control circuit.