| 摘要 |
<P>PROBLEM TO BE SOLVED: To enhance signal output (reflectance difference) of an L1 layer while maintaining recording sensitivity of an L0 layer when a recording capacity of a rewritable two-layer type optical recording medium is enlarged. <P>SOLUTION: In the rewritable two-layer type optical recording medium having a translucent information layer wherein the shortest mark length L<SB>min</SB>which can be recorded and reproduced satisfies relational formula 1<äL<SB>min</SB>/(λ/NA)}×4≤1.10 and at least a recording film and a reflection film are provided, a film thickness Trec (nm) of the recording film and a film thickness Tref (nm) of the reflection film satisfy one of following four relational formulae: (I) 4.5≤Trec≤6.0 and -3.4×Trec+35≤Tref≤-2.0×Trec+34, (II) 6.0≤Trec≤8.0 and -2.5×Trec+30≤Tref≤-2.0×Trec+34, (III) 8.0≤Trec≤9.5 and 10≤Tref≤-2.0×Trec+34, and (IV) 9.5≤Trec≤10.5 and 10≤Tref≤-5.0×Trec+62.5. <P>COPYRIGHT: (C)2009,JPO&INPIT |
