OPTICAL PICKUP DEVICE FOR OPTICAL DISK OF DIFFERENT TRACK PITCH

摘要

PROBLEM TO BE SOLVED: To provide an optical pickup device which can detect accurate tracking/focusing error signals for the optical disks having a different track pitches by tracking/focusing servo tracking using the light volume difference on both side of the track to make the tracking error offsets minimum when the objective lens move right and left.

SOLUTION: Tracking servo tracking is carried out by using a diffraction pattern of diffracted beams of side areas where tracking error offset becomes minimum when the objective lens moves right and left among diffracted beams reflected/diffracted on the optical disk. Focus servo tracking is carried out by using the diffraction pattern of the center area.

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