| 摘要 |
PURPOSE:To remarkably simplify adjustment for a laser power by automatically performing the adjustment for the laser power for respective level of recording, reproduction, and erasure as monitoring the laser power by using a CPU. CONSTITUTION:Two adjusting functions of the adjustment for the laser power at a stationary state by a laser output control circuit and that for a power response when a mode is switched are automatically performed by using the CPU 15. Thereby, the adjustment for the laser power can be remarkably simplified, however, the adjustment for the sensitivity of a PD 11 for monitoring should be performed necessarily. A power detection signal VPD having integral sensitivity for the laser power of an LD 10 is found with the monitor PD 11 and a monitor output amplifier 1. The signal VPD can be fetched with the CPU 15 at an appropriate timing via a sample-and-hold circuit 13 and an A/D converter 14. On the other hand, a power reference signal V1 is outputted from the CPU 15 via a latch 18 and a D/A converter 16, and the power reference signal V1 and the power detection signal VPD are inputted to a comparator 2, then, the difference of those signals V1 and VPD is found. |
