| 摘要 |
PROBLEM TO BE SOLVED: To precisely control the current of a laser diode in an optical disk device such as a CD-R. SOLUTION: An optical output of a laser diode 6, to which a driving current is supplied so that the level is varied by recording pulses, is detected by a monitoring photodetector 11. A voltage Va based on the above detection is extracted by a recording sample-and-hold circuit 16 and a reproducing sample- and-hold circuit 20. Then, a driving control voltage Vb is formed to obtain a reproducing power target value. Then, a current corresponding to the voltage Vb flows in the diode 6. Then, the value is compensated for so that offset components of the voltage Vb are eliminated and fluctuation of the voltage Vb caused by the fluctuation of the waveforms of an input voltage of the circuit 16 is suppressed. |
