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:
Apr. 29, 2008
Filed:
Nov. 15, 2004
Hisashi Senga, Kadoma, JP;
Toshio Matsumoto, Kyoto, JP;
Hiromichi Ishibashi, Ibaraki, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A laser control unit, a laser control circuit and a laser-power adjustment method are provided which are capable of controlling laser power precisely, even if an error is produced in the duty of an optical pulse. A light-receiving elementconverts the optical pulse into an electric signal and outputs a photo-detection signal; an LPFcalculates the average value of the optical pulse, based on the photo-detection signal; a DSPcalculates a light-emission power value, based on the average value of the optical pulse and the duty of the optical pulse, and calculates the difference between the light-emission power value and a target power value; an EP-ROMstores a correction value for correcting a calculation which is executed by the DSP; the DSPcorrects the calculation, based on the correction value, and controls an electric-current value which is supplied to a semiconductor laser, based on the calculation result which is obtained from the correction; and a laser drive circuitdrives the semiconductor laser, based on the electric-current value.