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:
Jan. 02, 2001
Filed:
Nov. 15, 1995
Tatsuo Chigira, Kanagawa-ken, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A video camera of the kind performing a power varying action on a zoom lens while keeping its variator lens and its focus lens in a predetermined relation comprises a memory for storing information on driving speeds at which the variator lens is to be driven at respective moving positions thereof, a position detecting circuit for detecting the positions of the variator lens and the focus lens, and a control circuit for driving the variator lens and the focus lens, on the basis of information on a driving speed of the variator lens read out from the memory according to the result of detection made by the position detecting circuit, in such a manner that a driving speed of the focus lens remains nearly constant in the neighborhood of a telephoto end position of the zoom lens. The video camera is thus arranged to be capable of uniformalizing the driving speed of the focus lens even in the neighborhood of the telephoto end position where the follow speed of the focus lens tends to suddenly increase. The focus lens is, therefore, allowed to accurately follow the variator lens irrespective of the position of the variator lens, so that zooming can be carried out without defocusing.