| 摘要 |
PURPOSE:To prevent the power of a main beam for recording/reproduction from becoming unstable by a return light from a magneto-optical disk and thereby to enable accurate detection of the power, by detecting that power. CONSTITUTION:A laser light transmitted through a beam splitter 13 is led to a sensor 12 through a microlens 14 and detected. A drive current of a laser diode 11 is regulated by a current based on an output signal of the sensor 12 so that the power of the emitted light of the diode 11 being detected be a set value. The laser light reflected on a slant 13a of the splitter 13 is converged on a magneto-optical disk 17 through an objective lens 16. When a laser beam of a recording power is applied to the disk 17, information is recorded on the disk 17 or erased therefrom, since a magnetic field is impressed on the disk 17 by a magnetic coil. When a laser beam of a reproducing power is applied, recorded information of the disk 17 is read out. According to this constitution, construction of the optical system for detection is simplified. |
