Optical pickup and optical information recording apparatus...

Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium

Reexamination Certificate

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Reexamination Certificate

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07911915

ABSTRACT:
An optical pickup includes a diffraction grating partitioned into three areas, in which the phase of periodic grating groove structure in an area is successively shifted from that in the adjacent area by 90°. In the generation of a differential push-pull signal, an amplification factor K for sub push-pull signals is varied depending on the type of the optical disk. By such composition of the optical pickup, amplitude deterioration of the tracking error signal accompanying displacement of the object lens is reduced.

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United States Notice of Allowance issued in U.S. Appl. No. 11/905,527 dated Dec. 1, 2009.

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