| 摘要 |
PURPOSE:To prevent recording defect or reproducing defect from being generated even when a temperature is changed by detecting the light quantity of a light output means in a state before generating the temperature change, holding a peak value at the time of recording and a peak value at the time of reproducing and afterwards generating a driving signal based on this peak value. CONSTITUTION:In the state before generating the temperature change, the light emitting amount of a semiconductor laser oscillator is detected by a photodetector 13 and this amount is held in a low-power side peak detection circuit 40 and a high-power side peak detection circuit 41 respectively as the peak value of a reproducing signal at the time of reproducing and the peak value of a recording signal at the time of recording. At the time of reproducing, the driving signal is generated based on the peak value of the reproducing signal held in the low-power side peak detection circuit 40; and at the time of recording, the driving signal is generated based on the peak value of the recording signal held in the high-power side peak detection circuit 41 so as to drive the semiconductor laser oscillator. Thus, the reproducing defect or the recording effect can be prevented without lowering the light output by the temperature change at the time of recording or reproducing. |
