| 摘要 |
PROBLEM TO BE SOLVED: To provide a writing material for optical disk, a writing tool for optical disk, a writer for optical disk, and an optical disk which secure reproducing characteristics as well as the index information volume. SOLUTION: The optical disk provided with a write layer 15 on a protection layer 14 is constituted. A constituent material (writing material) of the write layer 15 is made to satisfy the relation |T1-T2|<0.11 where T1 is the attenuation coefficient of reflected light obtained by radiating reproducing laser light to the optical disk on which index information (write layer 15) has been written by using the writing material and T2 is that obtained by radiating the laser light to the optical disk on which index information is not written. Since reproducing characteristics (jitter characteristics) are secured even when the write layer 15 is provided on a recording face, index information can be written on the recording face also. |
