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:
Feb. 10, 1998
Filed:
Sep. 01, 1995
Seiichi Yasukawa, Yotsukaido, JP;
Nikon Corporation, Tokyo, JP;
Abstract
An automatic focus adjustment device which accurately performs end point detection of the range of movement of a photographic lens to smoothly drive the photographic lens completely to a focus position. The automatic focus adjustment device includes a defocus amount detection device to detect a position deviation of the image position of a subject formed by the photographic lens from an image forming plane. An actuation amount necessary to drive the photographic lens by the detected defocus amount is calculated. An actual actuation amount decision device decides whether the actual actuation amount output to drive the lens is within a permissible range predetermined for the drive. A first lens displacement decision device decides whether the lens position changes during a predetermined first time period, and a second lens displacement decision device decides whether the lens position changes during a predetermined second time period when the actual actuation amount decision device decides that the actual actuation amount is outside the permissible range. The actual actuation amount setting device sets the actuation amount used to drive the lens according to the decisions by the first and second lens displacement decision devices.