| 摘要 |
PROBLEM TO BE SOLVED: To surely determine a defective disk with deteriorated reflectance. SOLUTION: When starting a DVD, a control unit 10A detects the wave height value of an RF signal when an optical pickup 3 performs a focus search operation as reflectance data of the DVD, starts various servos to read disk management information recorded in an innermost periphery, and stores, if a volume ID is not stored in a reflectance information storage part 11, optical disk reflectance information composed of the volume ID and current reflectance data in pairs in the optical disk reflectance information storage part 11. If the current volume ID has been stored in the optical disk reflectance information storage part 11, whether a difference between the paired reflectance data and the current reflectance is equal to or more than a predetermined fixed value. If equal to or more than the fixed value, a defective disk is determined to display warning. COPYRIGHT: (C)2008,JPO&INPIT
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