| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical disc medium which can be excellently reproduced by both compact disc reproducing apparatus and DVD reproducing apparatus and assures compatibility. SOLUTION: Almost identical pieces of information are recorded to a plurality of information recording layers of different kinds of parameters such as track structure, modulation system, logical format and physical format, etc., and a plurality of information recording layers are capable of realizing multilayer recording in the thickness direction of the disc so that data can be read by a plurality of optical information reproducing apparatuses in different laser wavelengths and focus distances. Moreover, an information recording layer similar to the recording format of the compact disc is formed on the substrate of almost 1.2mm and moreover the information recording layer similar to the recording format of DVD is formed in the position where the thickness is almost 0.6mm, thereby the data can be reproduced by optical information reproducing apparatuses for both compact disc and DVD. |
