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:
Apr. 30, 2002
Filed:
Sep. 26, 2000
Seiichi Kashiwaba, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A zoom lens apparatus having an optical axis includes a zoom cam tube arranged to rotate around the optical axis and having a cam groove for moving a variator lens along the optical axis, and a focus cam tube having a cam groove for moving a focusing lens along the optical axis, wherein the focus cam tube rotates around the optical axis and moves along the optical axis in association with the rotation of the zoom cam tube during zooming, and wherein a rotational speed of the zoom cam tube and a rotational speed of the focus cam tube during zooming are different from each other, so that the zoom lens barrel has excellent zooming operability by reducing torque changes in operation due to the zooming operation.