| 摘要 |
PURPOSE:To execute the light emitting power control of a semiconductor laser with high accuracy without receiving the fluctuation of current-light emitting power characteristic due to the temperature environment of a semiconductor laser or self-heating, etc., by providing a recording power setting means and an erasing power setting means. CONSTITUTION:When recording power is set, at first, a holding circuit 7 goes to a holding mode. Then, the output signal of a comparator 6 is held and reproducing power is held. In such a condition, a reference voltage Vref2 for recording is inputted to a switch element 4 by a first control signal from a circuit 5 and passed through the comparator 6 and a holding circuit 11. After that, the voltage is sent through a switch element 9 to a current source 10 for recording and erasing and a current for a recording power part is supplied to a semiconductor laser 1. Further, since a modulating signal, which is closed to a real writing frequency, is generated from a pseudo-signal circuit 12 and the current source 10 is turned on and off, the semiconductor 1 is not turned on by a direct current but turned on by a real information recording emitting pattern. Such a condition is repeated by the pseudo-ID/data part signal generating circuit 5 and the control of the recording power is executed with the high accuracy without receiving the fluctuation of the current-light emitting power characteristic. |
