OPTICAL DEVICE, AND METHOD AND DEVICE FOR IDENTIFYING RECORDING LAYER

摘要

PROBLEM TO BE SOLVED: To provide an optical disk capable of easily, highly reliably and quickly identifying each recording layer of the optical disk having a number of recording layers without needing any data demodulation. SOLUTION: On one side, first and second layer tracks 11 and 12 are provided as two recording layers. The first and second layer tracks 11 and 12 are formed so as to be respectively wobbled to have wobbling phases changed in the midway, and have different phase changing amounts.