OPTICAL PICKUP AND OPTICAL INFORMATION RECORDING DEVICE OR REPRODUCING DEVICE USING IT

摘要

PROBLEM TO BE SOLVED: To provide a new tracking error signal detecting means which depends less on the difference of track pitch of a disk and the tracking directional displacement of an objective lens and detects a practical tracking error signal in which tracking offset is always satisfactorily eliminated for a plurality of kinds of optical disks with different track pitches.

SOLUTION: A specific diffraction grating is used which is divided into three regions in each of which grating grooves are provided periodically so that the phase of the grating grooves is successively shifted at every 90 degree. An amplification factor of a sub-push-pull signal when generating a differential push-pull signal is made variable conforming to the kind of an optical disk.

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