| 摘要 |
PROBLEM TO BE SOLVED: To provide a tilt feature of an objective lens for irradiating a recording surface with a laser beam from an optical pickup always vertically even the optical disk has curvature, and an optical disk device with this feature. SOLUTION: The optical disk device 10 comprises: an optical pickup 12 which irradiates an optical disk D with a laser beam L and reads reflected light from the optical disk; an objective lens 14 which converges the laser beam emitted from the optical pickup; an actuator 16 for changing the angle of the objective lens against the reference plane for irradiating the optical disk with the laser beam; and an actuator control means 20 of controlling operation of the actuator. The device also comprises: a shape calculating means 20a of calculating an approximate expression showing an altitudinal location of the optical disk D from the reference plane; a location calculating means 20b of grasping the current location of the optical pickup 12; and a tilt angle calculating means 20c of calculating a tilt angle K of the optical disk D against the reference plane in the current location of the optical pickup 12, based on the altitudinal location of the optical disk D from the reference plane between two points separated at a predetermined interval from the current location of the optical pickup calculated by the approximate expression, and the horizontal interval between the two points. The actuator control means 20 controls the actuator 16 which tilts the objective lens 14 to a tilt angle K calculated by the tilt angle calculating means 20e against the reference plane. COPYRIGHT: (C)2005,JPO&NCIPI
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