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:
Mar. 24, 1981
Filed:
Mar. 20, 1979
Kazuya Hosoe, Machida, JP;
Yukichi Niwa, Yokohama, JP;
Tokuichi Tsunekawa, Yokohama, JP;
Mitsutoshi Owada, Yokohama, JP;
Noriyuki Asano, Kawasaki, JP;
Makoto Masunaga, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
This invention relates to a device for focus detection or distance detection in which one or more images of a target formed by an optical system are received by photoelectric light receiving means to obtain a photoelectric output regarding the imaging condition of the image of the target and this photoelectric output is electrically processed through a processing circuit to thereby provide an electrical output representing the focus adjusted condition of the optical system with respect to the target or the distance to the target. According to the improvements of the present invention, such device is provided with projector means for illuminating a limited part of the detection view field determined by the focal length of the optical system and the dimensions of the effective light receiving surface of the photoelectric light receiving means, detection means for detecting whether or not the signal put out by the photoelectric light receiving means regarding the imaging condition of one or more images of the target is a sufficiently proper signal to ensure accurate focus detection or distance detection by the processing circuit, and control means for controlling the projector means in accordance with the detection output from the detection means. When proper detection is not ensured during the focus detection or the distance detection, the projector means is driven by the control means in accordance with the detection output of the detection means and the projection image of the projected light formed thereby on the target is utilized to effect focus detection or distance detection.