| 摘要 |
PURPOSE:To record or erase always surely and suitably information on a recording medium by providing a light quantity control means, which controls stably the optical output of a light source to a prescribed value, and an optical beam suppressing means which operates an optical system means in accordance with a command signal without recording neither erasing. CONSTITUTION:The command signal is inputted to an optical beam suppressing circuit 7, and the output signal is connected to an optical system driving circuit 62 to operate the optical system means. Before information is recorded on or erased from a recording medium 2, the optical beam suppressing circuit 7 receives the command signal and is operated, and a defocusing current is flowed t a coil 54 through the optical system driving circuit 62 and the optical beam of a semiconductor laser 1 is defocused and irradiated on the recording medium 2, or a track transversing current is flowed to a voice coil 56 to move the optical beam to a part other than the information recording area on the recording medium. Thereafter, the semiconductor laser 1 emits the optical beam having enough optical output to record or erase information, and the quantity of light is detected by a photodetector 3, and the optical output is adjusted and controlled to a prescribed value automatically through a control circuit 41 and a light source driving circuit 42. |
