The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Patent No.:

US 8937855 B1

PDF
Full Text
Expired
Date of Patent:
Jan. 20, 2015

Filed:

Jun. 19, 2013
Applicant:

Hitachi Media Electronics Co., Ltd., Oshu-shi, lwate, JP;

Inventors:

Kazuyoshi Yamazaki, Yamato, JP;

Ken-ichi Shimada, Tuson, AZ (US);

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B 7/00 (2006.01);
U.S. Cl.
CPC ...
Abstract

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.


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Yamazaki, Kazuyoshi. (2015). 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 (U.S. Patent No. 8937855). U.S. Patent and Trademark Office. https://idiyas.com/patent/badge/8937855

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