Hitachi Media Electronics Co., Ltd.

Ken-ichi Shimada

Kazuyoshi Yamazaki

A holographic optical pickup device includes an optical axis split element for splitting a reference beam into two light beams in different propagation directions having polarized states substantially orthogonal to each other, angular variable elements for changing incident angle of the reference beam for irradiating an optical information recording medium, an image sensor for detecting a diffracted beam generated from a recorded region upon irradiation of the optical information recording medium with the reference beam to form a reproduction signal, and photodetectors for detecting the diffracted beam generated from the recorded region upon irradiation of the optical information recording medium with the reference beam. An angular error signal is generated for controlling the angular variable element using signals detected by the photodetectors.

Holographic optical pickup device, optical information recording and reproducing device, and method of reproducing optical information, having angular variable element arrangements for changing a light angle

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Tuson, AZ, United States of America

Ken-ichi Shimada