Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium
Patent
1990-02-22
1992-03-24
Envall, Jr., Roy N.
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Radiation beam modification of or by storage medium
369 13, 369112, 360114, G11B 700
Patent
active
050994700
ABSTRACT:
In an apparatus for reproducing information recorded in an opto-magnetic record medium, a linearly polarized light beam is made incident upon the record medium, a light beam reflected by the record medium is made incident upon a quarter wavelength plate whose principal axis is inclined with respect to the polarization direction of the incident linearly polarized light beam and is converted into one of elliptically polarized light beams having major axes perpendicular to each other depending upon the direction of magnetization in the record medium. The elliptically polarized light beam is made incident upon a polarization beam splitter for separating major and minor axis components from each other, and the thus separated major and minor axis components are received by first and second photodetectors, respectively. Output signals from the photodetectors are supplied to a differential amplifier to drive a difference therebetween representing a reproduced information signal. The information signal having a high C/N ratio can be reproduced without being influenced by a phase difference caused by the optomagnetic record medium and/or optical elements constituting of an optical system of the apparatus.
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Envall Jr. Roy N.
Olympus Optical Co,. Ltd.
Tran Thang V.
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