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. 07, 2009
Filed:
Jun. 15, 2005
Naoto Nakahara, Saitama, JP;
Naoto Nakahara, Saitama, JP;
Hoya Corporation, Tokyo, JP;
Abstract
A focus detection apparatus includes a lens drive mechanism for moving a focusing lens group, and a controller for detecting a contrast value of the object image and moving the focusing lens group. The controller calculates a difference between maximum and minimum contrast values detected at the different positions of the focusing lens group; compares contrast values at two adjacent lens positions to determine whether the contrast value increases successively and subsequently decreases successively; detects a maximum contrast value, if the contrast value increases successively and subsequently decreases successively; calculates the maximum contrast value via a point of intersection between straight lines of two linear approximation expressions if the difference is equal to or greater than a predetermined value; calculates the maximum contrast value from a quadratic approximation expression, if the difference is smaller than the predetermined value.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile