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Novel Structure for Magneto-Optical Disks

IP.com Disclosure Number: IPCOM000057292D
Original Publication Date: 1988-Apr-01
Included in the Prior Art Database: 2005-Feb-15

Publishing Venue

IBM

Related People

Authors:
Brunsch, A Pokrowsky, P Zapka, W [+details]

Abstract

Magneto-optical disks must have a groove structure for guiding the optical read/write head. The groove structure generally used has a spacing of 1.6 mm, a groove width of 0.5 to 1.0 mm and a depth of 50 to 100 nm. The servomechanism for guiding the optical head is controlled as described below. If the light beam is incident on the groove edges, part of the light is diffracted, leading to a change in the light distribution on the 4-quadrant detector, with the control circuit emitting a signal to the servomechanism. Compared with non-structured disks, the signal-to-noise ratio and the bit error rate of structured disks are subject to a noticeable deterioration.