Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium
Reexamination Certificate
2011-05-03
2011-05-03
Tran, Thang V (Department: 2627)
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Radiation beam modification of or by storage medium
C369S044370, C369S120000
Reexamination Certificate
active
07936658
ABSTRACT:
The present invention provides a photodetector capable of generating highly accurate tracking and focusing error signals free of variations in light quantity caused by interference, in an optical pickup with a two-wavelength multilaser. The photodetector comprises first three light receiving areas arranged linearly to receive three light beams respectively resulting from splitting of a light beam emitted from a laser light source of a first wavelength and second three light receiving areas arranged linearly to receive three light beams respectively resulting from splitting of a light beam emitted from a laser light source of a second wavelength longer than the first wavelength. The distance between both-end light receiving areas out of the first three light receiving areas is longer than the distance between both-end light receiving areas out of the second three light receiving areas.
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Office Action issued in Japanese Patent Application No. 2006-044644 on Aug. 17, 2010.
Inoue Masayuki
Izumi Katsuhiko
Kawamura Tomoto
Ohnishi Kunikazu
Antonelli, Terry Stout & Kraus, LLP.
Hitachi Media Electronics Co. Ltd.
Tran Thang V
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