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. 03, 1993
Filed:
Sep. 26, 1991
Keiji Moriyama, Yokohama, JP;
Nikon Corporation, Tokyo, JP;
Abstract
In a focus detecting apparatus provided with a focus detecting optical system comprising a field mask provided at the predetermined image plane position of a photo-taking lens and having an opening corresponding to a focus detection area, a condenser lens provided rearwardly of the field mask and positioned near the predetermined image plane of the photo-taking lens, a pair of stop masks provided rearwardly of the condenser lens and dividing the pupil of the photo-taking lens into two areas by a pair of openings therein, and a re-imaging lens system having a pair of re-imaging lenses corresponding to the openings in the stop mask, the image by the photo-taking lens being re-formed as secondary images on a pair of photoelectric conversion element arrays by the focus detecting optical system, the focus adjusted state of the photo-taking lens being detected from the relative positional relation between the secondary images, a plurality of focus detecting optical systems are disposed so that they have at least two focus detection areas about a position off the optical axis of the photo-taking lens and the directions of detection of these focus detection areas differ from each other, and the center positions of the pairs of openings in the stop masks of the focus detecting optical systems are set to different positions.