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. 30, 1993
Filed:
Aug. 27, 1991
Applicant:
Inventors:
Shotaro Yokoyama, Kawasaki, JP;
Takashi Nishibe, Kawasaki, JP;
Assignee:
Fuji Electric Co., Ltd., Kawasaki, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
2502 / ; 307311 ;
Abstract
An optical sensing circuit having a photodiode, a differential amplifying circuit, and a comparator. The differential amplifying circuit is provided with an integral capacity. Adjusting capacities are connected in parallel to or disconnected from the integral capacity. A composite capacitance of the integral capacity and the adjusting capacities is adjusted by a control circuit so that the composite capacitance increases with increase of light intensity. This makes it possible to improve sensitivity of the optical sensing circuit for the light intensity and to widen the dynamic range for light sensitivity.