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:
May. 24, 1983
Filed:
Jun. 29, 1981
Seijiro Tokutomi, Tokyo, JP;
Ryota Ogawa, Kawagoe, JP;
Michiro Ohishi, Tokyo, JP;
Kazuo Nakamura, Tokyo, JP;
Masao Jyojiki, Tsurugashima, JP;
Satoru Tachihara, Wako, JP;
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A focus detecting device having two concave mirrors for reforming the image of an object which is formed between a lens and the focal plane of lens, and for dividing said image two same secondary images. Two light receiving element arrays are provided in the image forming planes of the secondary images. A signal processing circuit subjects the outputs of the light receiving element arrays to produce a signal indicating whether or not the lens is focussed on the object. By means of the two concave mirrors adapted to form said secondary images, the two secondary images are shifted in the opposite directions on the light receiving element arrays at the time of defocussing so that the difference between the outputs of the two light receiving element arrays is not zero. At the time of proper focus the two secondary images are located at equivalent positions on said light receiving element arrays so that the difference between the outputs of the two light receiving element arrays is zero. A signal processing circuit produces a signal indicating the establishment of the proper focus.