| 摘要 |
PURPOSE:To stabilize an optical output at each mode irrespective of a temperature variation, by converting a current flowing to a laser diode of a laser light generating device for a magneto-optical disk, to a voltage by a current - voltage transducer of a gain variable type, holding its minimum value and bringing the diode to a feedback control. CONSTITUTION:A current flowing through a laser diode 22 is monitored through a photodiode, erased by a system controlling circuit 29, and the same converted voltage as the time of a reproducing mode is generated by a gain variable type current - voltage transducer 25 whose gain is controlled by a transistor Q3 which becomes ON at the time of a recording mode. This voltage is further processed by a sample holding circuit 26 for holding the minimum value, and with respect to a binary current at the time of a recording mode, as well, the same converted voltage as the time of a reproducing mode is generated. By the converted voltage, a shunt current flowing to the diode 22 through a shunt controlling circuit is brought to a feedback control and an optical output at the time of each mode of the laser diode whose temperature dependency is large is stabilized irrespective of a temperature variation. |
