MULT-ILAYER INFORMATION STORAGE SYSTEM

摘要

PROBLEM TO BE SOLVED: To suppress cross-talk and to compensate spherical aberration in an optical multi-recording layer recorded layer and a scanner device.

SOLUTION: The optical information storage system has a multi-recording-layer record carrier (1) and the scanner device (10) for scanning layers (3, 4, 5) by a scanning spot (15) formed by irradiation beam (12). The scanner produces a radiation beam which is compensated for spherical aberration for a single height of the scanning spot with the stack (2) of layers. The height of the stack is determined by the maximum spherical aberration permissible for the system. The number of layers in the stack is determined by the minimum distance between layers, which depends on the crosstalk in the servo error signals due to currently unscanned layers.

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