OPTICAL DISK, METHOD FOR CORRECTING ABERRATION, AND OPTICAL DISK DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an optical disk where a spherical aberration caused by the thickness deviation of a transparent substrate can be corrected without causing the increase of the size of a device and the increase of the cost. SOLUTION: The recording surface of an information recording layer 4 where small spots for recording or reproducing information are formed is covered with a transparent substrate 3. A specific area 2 is provided at part of a read-in area formed in the disk innermost peripheral area of the recording surface of the layer 4, and a specific pattern with which the spherical aberration of the minute spots generated due to the deviation from the regulated value of the thickness of the substrate 3.