PURPOSE: To manufacture a magneto-optical disk having a stable characteristic by detecting reflected quantity of light of a magneto-optical disk and computes absorption quantity of light of a disk recorded film, and controlling outgoing light of a light beam so as to be kept constant.
CONSTITUTION: Outgoing light of a semiconductor laser 7 is condensed on a magneto-optical disk 2 via a condenser lens 4. Quantity of reflected light from the disk 2 is detected by a quantity of reflected light sensor 6, the voltage output is processed by subtraction with voltage from the reference power sources 12, 13 in voltage subtracters 14, 15 and absorption quantity of light of the disk 2 is calculated. And quantity of the outgoing light of light beam is controlled by a semiconductor laser driver 16 so that absorption quantity of the light is kept constant. Consequently, a characteristic of recorded films between recording tracks using optical beam heating can be irreversibly changed. Therefore, the magneto-optical disk having wide overwrite power margin can be stably manufactured using a magnetic field modulation system.
ORUKAWA MASAHIRO
MIYATAKE NORIO
UCHIDA KIYOSHI
