Browse Prior Art Database

Magneto-Optical Recording System

IP.com Disclosure Number: IPCOM000098364D
Original Publication Date: 1960-Aug-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Hagopian, JJ: AUTHOR [+2]

Abstract

Data are magnetically recorded on a magnetizable coating on one side of a transparent disk. The data are reproduced optically by a reading station disposed on the opposite side of the disk.

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Magneto-Optical Recording System

Data are magnetically recorded on a magnetizable coating on one side of a transparent disk. The data are reproduced optically by a reading station disposed on the opposite side of the disk.

The recording disk 10 consists of a transparent member 11 to which a magnetizable layer 12 is secured between two layers 13, 14 of a ceramic alumina material. Data are magnetically recorded on layer 12 by means of a transducer 15 as the disk rotates. Disk 10 is movable, through shaft 16, to position different concentric recording tracks adjacent the read write station.

To read the recorded data, a beam of polarized light from a source 17 is projected onto the disk at a point immediately overlying transducer 15. This beam is reflected from the disk to a crossed analyzer 18. As a result of the Kerr magneto optical effect, the plane of polarization of the reflected beam is rotated if a magnetic bit is present in material 12 at the point of beam impingement. No rotation occurs if a bit is not present.

Crossed analyzer 18 detects the rotation or non-rotation of the reflected beam and the output of the analyzer is a pulse train corresponding to the bits on the rotating disk.

Ceramic layer 13 provides mechanical protection for the magnetic film 12. The transparent layer 14 produces multiple internal reflection of the polarized beam to enhance its optical rotation.

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