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. 31, 1982
Filed:
Aug. 19, 1980
Takashi Kawabata, Kamakura, JP;
Tokuichi Tsunekawa, Yokohama, JP;
Kazuya Hosoe, Machida, JP;
Takao Kinoshita, Tokyo, JP;
Shinji Sakai, Tokyo, JP;
Tatsuya Taguchi, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
Disclosed is a TTL (Through-The-Lens) type focus detecting device for use in an interchangeable lens-equipped camera, in which a plurality of lenslets are positioned at or near the prescribed focal plane of the objective lens, each of the lenslets is associated with two or more pairs of photosensitive elements. Upon attachment of an objective lens to the camera body, one of the pairs of photosensitive elements for each lenslet is automatically selected to operate on the basis of the dimensions of the used objective lens. The outputs of the selected pairs of photosensitive elements for all the lenslets are processed to detect whether or not a positional difference between two images of an object formed with light beams from the objective lens at respective virtual exit pupils lying in almost symmetry with respect to the optical axis thereof is present, whereby the detection of whether or not the objective lens is in-focus is indicated.