Relation between Signal Quality and Groove Shape in Magneto-Optical Disk(1)

The effect of groove shape on recording media was measured with a static measurement system developed by the authors to investigate media magneto-optic characteristics in the microscopic range. Reflectivity decreased as the depth of the groove increased due to the groove diffraction effect. Decrease in reflectivity also seemed to be the cause of reduction in the rotation angle. The coercive force only reached a critical variation point when the groove was shallow, which seemed to be because grooves deeper than the 20nm film thickness of the experimental samples divided the media in two.