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:
Nov. 03, 2009

Filed:

Feb. 15, 2007
Applicants:

Richard Kok Keong Lum, Singapore, SG;

Lei Chen, Singapore, SG;

Inventors:

Richard Kok Keong Lum, Singapore, SG;

Lei Chen, Singapore, SG;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01J 1/44 (2006.01); H03F 3/08 (2006.01); H04B 10/06 (2006.01);
U.S. Cl.
CPC ...
Abstract

A light sensor having a photocurrent subsection and an interface circuit is disclosed. The photocurrent subsection includes a photodetector, an amplifier, a diode and an impedance element. The first photodetector generates a current between a first node and a power rail in response to being illuminated with light. The interface circuit generates an output signal that is related to the logarithm of the intensity of light that is incident on the photodetector. The impedance element is constructed in a manner that compensates for the thermal dependency of the impedance through the diode. Additional photocurrent subsections can be added to further reduce the thermal dependency of the output signal.


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