| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical disk and an optical disk device wherein access time can be shortened. <P>SOLUTION: A plurality of information layers L1, L2 and L3 different in optical disk specification are provided on an optical disk and are laminated in the thickness direction of the optical disk 1. The information layers L1, L2 and L3 are disposed in this order in positions where distances from the surface to the information layers are 0.1 mm, 0.6 mm and 1.2 mm, respectively. The information layers L1, L2 and L3 satisfy specifications of a BD, a DVD and a CD, respectively and the information layer L1 has the highest recording density and the information layer L3 has the lowest recording density. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
