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. 07, 1999
Filed:
Apr. 03, 1997
Masahide Hirasawa, Sagamihara, JP;
Toshimichi Ouchi, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A lens control device for an inner focus lens system has a first lens group for zooming; a second lens group for focusing; a first zooming unit for controlling the second lens group for correcting the displacement of the focal plane resulting from the movement of the first lens group; a memory for memorizing the relative position of the second lens group to the first lens group in a zooming operation by the first zooming unit; a calculation unit for calculating the moving speed of the second lens group based on the memorized data, in order to maintain the focused in the course of movement of the first lens group; and a second zooming unit for controlling the second lens group according to the result of calculation. In this configuration, the positions of the focusing lens is memorized in a zooming operation from the telephoto side to the wide angle side, and, in the zooming operation from the wide angle side to the telephoto side, which is apt to generate a defocus, the focusing lens is controlled by the memorized data, in order to avoid generation of such defocus.