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:
Aug. 07, 2001
Filed:
Mar. 03, 1999
Yusuke Ohmura, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A focus detecting device for detecting a focusing state of an objective lens includes a field lens disposed adjacent to a prescribed image forming plane of the objective lens and having lens surfaces which differ in shape from each other correspondingly with a plurality of focus detecting areas, a reimaging lens disposed behind the field lens and having a pair of lens parts for forming a pair of light distributions for each of different pupils of the objective lens, and a light receiving sensor arranged to receive the pair of light distributions so as to detect the focusing state of the objective lens, wherein a first area of the field lens has a first field lens part having an optical axis which coincides with an optical axis of the objective lens, and a second area of the field lens which differs from the first area has a second field lens part having an optical axis which does not coincide with the optical axis of the first field lens part. The focus detecting device is thus compactly arranged and is capable of highly accurately making focus detection for a plurality of focus detecting areas.