| 摘要 |
PURPOSE:To always obtain prescribed recording output even when the characteristic of a semiconductor laser changes by providing a level holding circuit, performing feedback control even at the time of recording, and holding recording current just before by the level holding circuit provided newly at the time of reproduction. CONSTITUTION:At the time of switching a mode from a recording state to a reproducing state, a recording current value just before is held by the level holding circuit 8. Next, when the mode is switched from the reproducing state to the recording state, a few quantity of change is generated in the semiconductor laser 13 during that time, and almost prescribed recording output can be obtained immediately after the switching. Thereby, it is possible to apply power control by the feedback control even in recording in a power control device with slow response. In such a way, it is possible to always obtain the prescribed recording output even when the characteristic of the semiconductor laser 13 changes due to the influence of return light from a medium, temperature change, or deterioration in the lapse of time, etc. |
