| 摘要 |
PURPOSE:To set an optimum recording laser intensity at the time of irradiating a recording medium with laser to write a signal. CONSTITUTION:The laser intensity is modulated in a laser driving circuit 4 by the signal obtained by adding signals having a frequency f1 and a lower frequency f2 in a means 3, and the laser intensity is stepwise changed to record the addition signal on a recording medium 6, and the recorded signal is reproduced, and the recording laser intensity is set to such laser intensity by a laser output setting circuit 5 that the level of f1-f2 or f1+f2 is minimized with respect to relation between the laser intensity and the output of a level detector 11 which detects the level of f1-f2 or f1+f2. Thus, the optimum recording laser intensity is always set independently of the variance in recording sensitivity of the recording medium, the temperature detection precision of the recording medium, and the initialization precision of the laser intensity. |
