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. 06, 1981
Filed:
Jan. 31, 1980
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
An automatic focus detecting device for a camera in which a self-scanning photoelectric element array is scanned at a rate depending upon the average amount of light reflected from an object being photographed so that accurate focus detection is maintained over a wide range of illumination conditions. An average illumination detecting element is disposed at a position near or at a position optically equivalent to that of the microphotoelectric elements of the element array. A low-pass filter couples the output of the average illumination detecting element to a clock pulse generator which produces clock pulse signals of which the frequency varies according to the smoothed output signal from the low-pass filter representing the average illumination. As the brightness of the object increases the frequency of the clock pulse signal correspondingly increases to compensate for variations in brightness of the object.