Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
2005-02-01
2005-02-01
Korzuch, William (Department: 2655)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S044410, C369S053280, C369S112010, C369S112150
Reexamination Certificate
active
06850472
ABSTRACT:
An optical pickup device includes a detection-use condenser lens for focusing a reflected light from a disk of a light emitted from a light source; a hologram element for dividing a light passed through the detection-use condenser lens into a light passed through a high numerical aperture region and a light passed through a low numerical aperture region; and a photodetector including at least a first light receiving element for detecting the laser beam which passed through the high numerical aperture region and a second light receiving element for detecting the laser beam which passes through the low numerical aperture region. Based on output signals from the first light receiving element and the second light receiving element, a focus error signal FE1and a focus error signal FE2are prepared respectively. According to an output value of the photodetector, a focus control is performed based on the error signal FE1or the focus error signal FE2.
REFERENCES:
patent: 4850695 (1989-07-01), Mikuriya et al.
patent: 5708638 (1998-01-01), Braat et al.
patent: 07-006372 (1995-01-01), None
patent: 10-500526 (1998-01-01), None
patent: 2000-011401 (2000-01-01), None
patent: 2000-163796 (2000-06-01), None
Miyazaki Osamu
Nakano Ikuo
Conlin David G.
Korzuch William
Ortiz-Criado Jorge L.
Sharp Kabushiki Kaisha
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