METHOD FOR INTENTIONALLY DEGRADING CONTENT OF OPTICAL RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide a method for intentionally degrading a content of an optical recording medium.

SOLUTION: In the field of optical information recording, the method for intentionally degrading information is provided for preventing an abusage or an illegal use, by which laser power lower than normal power for reading information recorded with super resolution is applied to the medium. The method originates from observation that the laser power lower than the super resolution reading power brings irreversible degradation of recorded information. The observation is performed for the medium having a three layer structure including two ZnS/SiO2layers (12, 16) and an InSb or GaSb layer (14) therebetween. The method is applied for protecting data to be carefully treated.

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