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:
Oct. 28, 1980
Filed:
Dec. 19, 1978
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A focus detecting device in a camera having an optical member or an optical system for obtaining two images from an object and an optical member for displacing said two images in opposite directions or displacing one of said two images. Two minute photoelectric conversion element groups are used for converting variations in light quantity of portions of the object into electrical signals. A photographing lens projects the image of the object onto the minute photoelectric conversion element groups. A circuit calculates outputs ##EQU1## from the outputs of minute photoelectric conversion elements forming the minute photoelectric conversion element groups. A circuit which has a first calculation function for calculating V.sub.out-3 =V.sub.out-1 +V.sub.out-2 and a second calculation function for calculating V.sub.out-4 =V.sub.out-1 -V.sub.out-2 so that when V.sub.out-3 becomes higher than a predetermined value, different outputs are produced under conditions that V.sub.out-4 >.epsilon..sub.1, .epsilon..sub.1 .gtoreq.V.sub.out-4 .gtoreq. .epsilon..sub.2, and .epsilon..sub.2 >V.sub.out-4. A display produces different displays according to the different outputs where n is the number of the minute photoelectric conversion elements forming each of the two minute photoelectric conversion element groups, m is a number of a minute photoelectric conversion element, i is the output of a minute photoelectric conversion element in one of the two minute photoelectric conversion element groups, i' is the output of a minute photoelectric conversion element in the other minute photoelectric conversion element group, .epsilon..sub.1 and .epsilon..sub.2 are predetermined constants.