| 摘要 |
PURPOSE: A radial tilt detector is provided to obtain accurate detection values using a head with a simplified configuration without any increase in costs. CONSTITUTION: A radial tilt detector includes an optical head, a focus actuator(9), a driver(10), a velocity detector(11), and a radial tilt calculation processor(15). The optical head projects a light beam onto a recording face of a rotating disk and receives the light reflected from the recording face. The focus actuator adjusts a focus position on which the light beam is focused. The driver generates a driving signal for driving the focus actuator. The velocity detector receives the driving signal and outputs accelerated velocity in the direction of the optical axis of the light beam on the focus position. The radial tilt calculation processor receives the accelerated velocity and a distance between the position of the recording face on which the light beam is incident and the center of the disk, and outputs a radial tilt using linear velocity or speed of revolution of the disk.
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