| 摘要 |
PROBLEM TO BE SOLVED: To obtain optimum external magnetic field intensity and laser power independently of tilt of a recording medium by controlling the output of external magnetic field in accordance with the position in the direction of the circumference of the recording medium at a position at which a disk type recording medium is irradiated with a light beam. SOLUTION: A MPU 14 of an optical disk 1 has a read-power setting table 14a for controlling read-power for each sector, a write-power setting table 14b for controlling write-power for each sector, and an external magnetic field setting table 14c for controlling external magnetic field intensity for each sector, in an internal memory. The MPU 14 controls a laser diode control circuit 24 so that read-power and write-power are controlled in accordance with setting values of the read-power setting table 14a and the write-power setting table 14b. Also, the MPU 14 controls a driver 42 in accordance with the setting value of the external magnetic field intensity setting table 14c and controls external magnetic field intensity.
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