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:
Jun. 21, 1977
Filed:
Oct. 15, 1974
Kazuya Hosoe, Machida, JA;
Hiroshi Aizawa, Machida, JA;
Seiichi Matsumoto, Yokohama, JA;
Hideo Yokota, Tokyo, JA;
Canon Kabushiki Kaisha, Tokyo, JA;
Abstract
The present invention relates to a method and a device for detecting visibility of the image of an object for adjusting the focus of an optical system. The invention is especially suitable to an optical instrument such as camera, using photo-electric conversion elements having non-linear resistance -- intensity of illumination characteristics such as cadmium sulfide CdS or cadmium selenide CdSe, etc. The invention is characterized in that the photo-electric effect of the above mentioned photo-electric conversion elements will have mutually reverse characteristics depending on the properties inherent to the photo-electric conversion elements, to the arrangement of the electrode and the electric circuit, and further on the state of the image of an object formed on said photo-electric conversion elements. An electric circuit to enhance object image visibility is disclosed which makes use of these characteristics.