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.

Date of Patent:
Dec. 22, 1987

Filed:

Jan. 13, 1986
Applicant:
Inventor:

Shigeyuki Akita, Okazaki, JP;

Assignee:

Nippon Soken, Inc., Nishio, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
2502 / ; 307311 ;
Abstract

A photo-electric conversion device includes a first photodiode in which a current is changed in accordance with a light intensity; a second photodiode which is connected to the first photodiode and in which a current flows in the same direction as that in the first photodiode; a light shielding structure for shielding the second photodiode with regard to light; a capacitor, connected in parallel with the second photodiode, for charging/discharging a current from the first photodiode; and an oscillator circuit for performing a switching operation in accordance with the charging/discharging operation of the capacitor so as to generate an oscillation voltage output. The light intensity is thus converted into a frequency of the oscillating voltage, and dark current in the first photodiode is discharged through the second photodiode such that the capacitor is always charged only by a current caused by received light detected by the first photodiode.


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