| 摘要 |
PURPOSE:To keep the optical output of a laser diode in a prescribed value in a rating range and to safely and surely record information by suppressing the fluctuation of the optical output of the laser diode at the time of recording completely from the upper and the lower. CONSTITUTION:A laser beam generator 21 constant-value-controls the maximum value of the optical output of a laser diode 3 by variable-controlling a recording current by a recording control circuit 22 at the time of recording a signal to an optical disk and variable-controls the minimum value of the optical output by a reproducing and recording control circuit 23 to constant-value-control the optical output at the time of reproducing the signal to the optical disk. Consequently, the fluctuation of the optical output of the laser diode 3 at the time of the recording can be completely suppressed from the upper and the lower and inconvenience that the wandering of storage contents change the minimum value of the recording current into an arbitrary value can be prevented. Thus, even when a current-optical output converting characteristic fluctuates by the influence of an ambient temperature, the optical output of the laser diode 3 can be kept at the prescribed value in the rating range and the information can be recorded safely and surely. |
