| 摘要 |
PURPOSE:To guarantee a long life to recorded information and, at the same time, to improve the readout error rate by modifying the reproducing S/N condition, by setting the power level of an optical storage reproducing device at the standby time lower than the power level at the operating time. CONSTITUTION:A fixed current I1 from the 1st current supplying circuit 1 and another fixed current I2 from the 2nd current supplying circuit 2 are inputted in a switching circuit 3 and the circuit 3 is switched to the readout operating condition or readout standby condition in accordance with the presence or absence of a readout instruction. Under the readout condition, the current I2 is selected and, under the standby condition, the current I1 is selected. Then the output current of the switching circuit 3 is supplied to a semiconductor laser diode 4. In this case, a long life can be guaranteed to recorded information and, at the same time, the reproducing S/N ratio can be modified and, as a result, the readout error rate can be improved, when the power level at the time of standby time is set lower than the power level of the readout operating time. |
