| 摘要 |
PROBLEM TO BE SOLVED: To correct tilt of an optical disc properly even if the installation attitude of a tilt sensor is varied through aging to produce an offset from actual tilt. SOLUTION: An aberration correcting means 23 controls inclination of an objective lens actuator 22 to adjust aberration occurring in the light spot projected onto an optical disc 4. A reference member 24 has a reference plane 25 parallel with the mounting face 26 of a turntable 12. Before information is recorded/reproduced onto/from the optical disc 4, a tilt sensor 1 detects inclination of the reference plane 25 and a detected value is stored in an offset value memory means 27. During recording/reproduction onto/from the optical disc 4, the tilt sensor 1 detects inclination in the vicinity of the reproducing or recording position on the surface of the optical disc 4 and a value obtained by subtracting a value stored in the offset value memory means 27 from the detected value is fed back to the aberration correcting means 23.
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