Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium
Patent
1995-03-10
1997-08-12
Hindi, Nabil
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Radiation beam modification of or by storage medium
369124, G11B 700
Patent
active
056573073
ABSTRACT:
An optical data reading method and apparatus for photoelectrically converting reflection light of a laser beam radiated onto a recording medium and thereby reproducing digital data recorded in the recording medium, performing a coherent detection by photoelectrically converting a first laser beam having a light frequency .nu..sub.1 and a second laser beam having a light frequency .nu..sub.2, where .nu..sub.1 -.nu..sub.2 .gtoreq.R (R: rate of reading the digital data), in a state where wavefronts of the first and second laser beams are aligned with each other, detecting temporal changes of either an amplitude or a phase of a beat signal component of the first and second laser beams, having a frequency of (.nu..sub.1 -.nu..sub.2) and being included in an photoelectrically converted output, and reading the digital data recorded in the recording medium based on a result of detection.
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U.S. Patent Application Serial Number 08/125,473 to Taneya (filed Sep. 22, 1993).
Kawanishi Hidenori
Morioka Tatsuya
Shimonaka Atsushi
Taneya Mototaka
Hindi Nabil
Sharp Kabushiki Kaisha
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