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. 15, 1999
Filed:
Aug. 18, 1997
Applicant:
Inventors:
Assignee:
Hamamatsu Photonics K.K., Hamamatsu, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
2503381 ; 2502 / ;
Abstract
A light chopper periodically transmits and blocks light, and first a dark current cancelling circuit determines an approximate mean value of the dark current from a photodiode when the light is blocked and cancels thus the mean value from the current signal fed into the integrated circuit, add to this, a differential arithmetic circuit that subtracts the remaining dark current component from the output of the integration circuit, thus the remaining signal indicates only the signal current component.