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:
Nov. 07, 2006
Filed:
Jan. 28, 2002
Hideaki Yano, Osaka, JP;
Kenji Asano, Kakamigahara, JP;
Takanori Kishida, Ogaki, JP;
Sanyo Electric Co., Ltd., Moriguchi, JP;
Abstract
A disk recording-playback device including a laser drive circuit for feeding a drive signal to an optical head and adjusting the power of a laser beam irradiated by the optical head, an error correcting circuit for detecting an error rate of a reproduced signal, and a system controller for controlling operation of the laser drive circuit for signal reproduction and signal recording based on the output of the error correcting circuit. The system controller successively sets the laser powers to at least three different values, obtains evaluation data for each laser power, approximates the relationships between the laser powers and the evaluation data to a quadratic curve, whereby an optimum laser power is derived corresponding to a vertex of the quadratic curve. Accordingly the optimum reproduction power and recording power are set, to thereby record and reproduce signals with high accuracy.