Dynamic information storage or retrieval – Storage or retrieval by simultaneous application of diverse... – Magnetic field and light beam
Patent
1993-05-03
1995-07-11
Epps, Georgia Y.
Dynamic information storage or retrieval
Storage or retrieval by simultaneous application of diverse...
Magnetic field and light beam
369110, G11B 1100
Patent
active
054327601
ABSTRACT:
In order to measure a phase difference of an opto-magnetic disk having a substrate and a magnetic record layer, linearly polarized light is made incident upon the magnetic layer of the disk from the side of the substrate and light reflected by the disk is received to derive an information signal recorded in the disk, while the opto-magnetic disk is rotated at a usual reproducing speed. A phase compensator arranged in an optical path of the light reflected by the disk is adjusted to change a phase difference introduced by the phase compensator into the light reflected by the disk, while a level of amplitude and/or C/N of the reproduced information signal is monitored. A value of the phase difference introduced by the phase compensator when the amplitude and/or C/N of the reproduced information signal becomes maximum is derived as a measured phase difference of the opto-magnetic disk.
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Birefringence Evaluation System for Magneto-Optical Disc, by Matsui et al., pp. 1-7.
Analysis of Signal to Noise Ratio in Magneto Optical Disk Using a Polarization Simulator, by Toda et al., pp. 273, 274, 277, 280, Denshi Joho Tsushin Gakkai Ronbunshi '88/2 vol. J71-C No. 2.
Fujiwara Yasuhiro
Yoshizawa Akihiko
Epps Georgia Y.
Hindi Nabil
Olympus Optical Co,. Ltd.
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