| 摘要 |
PURPOSE:To form a highly reliable optical disk device having high speed accessibility by separating a light beam to detect deviation of an optic axis separately from light that irradiates onto a light disk, reflecting it by a part of an actuator, and correcting the optic axis deviation making it detectable. CONSTITUTION:A beam of light separated by a beam splitter 18 passes a lambda/4 plate 19 and reflected by a mirror 20. The first beam reflected by disk 23 and the second beam reflected by the mirror 20 are composed again by the beam splitter 18 and return to an optic system 10. The plane of polarization of light reflected by the disk 23 is rotated by 90 deg. by passing the lambda/4 plate 19 twice, and reflected by a polarization beam splitter 14 and goes to a detector 29 through a lens 27. Correction signals relating to the disk such as focus error signals, track error signals, reproduction signals etc.are obtained in the detector 29.
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