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. 11, 2014

Filed:

Oct. 10, 2012
Applicant:

Canon Kabushiki Kaisha, Tokyo, JP;

Inventors:

Masanori Shibata, Kawasaki, JP;

Yoshikazu Yamazaki, Sagamihara, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01J 1/32 (2006.01); H05B 37/02 (2006.01); G01D 5/347 (2006.01);
U.S. Cl.
CPC ...
G01D 5/347 (2013.01); G01D 5/34715 (2013.01); H05B 37/02 (2013.01);
Abstract

A light-emitting element driving circuit comprising, a light-emitting element, a driving unit which has a control terminal and is configured to drive the light-emitting element according to a potential of the control terminal, a node connected to the control terminal, a monitor configured to monitor an emitted light amount of the light-emitting element, a potential control unit configured to control a potential of the node so that the emitted light amount of the light-emitting element approaches a target value, and an auxiliary potential control unit configured to assist potential control of the node by the potential control unit when a difference between the emitted light amount of the light-emitting element detected by the monitor and the target value is larger than a reference amount.


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