| 摘要 |
PURPOSE:To correct the transient answer of a laser oscillator at start of a recording job by controlling the input voltage of an error amplifier contained in an APC circuit before and after the recording job. CONSTITUTION:A monitor amplifier 2 is prepared to detect the optical output of a laser oscillator 1 together with an APC (automatic light quantity control) circuit 4 which controls the light quantity of the oscillator 1 at recording, the drive circuits 3 and 5 for the oscillator 1, and a circuit which sets the input of the circuit 4 so as to obtain at reproduction the same voltage value as that applied to the circuit 4 at recording. Then the input of the circuit 4 is set so that the voltage value applied to the circuit 5 at recording is obtained at reproduction. Thus it is possible to correct the transient answer of the drive current of the oscillator 1 when a recording job is started. |
