OPTICAL DATA STORAGE MEDIUM FOR WRITE ONCE RECORDING

摘要

A dual-stack optical data storage medium (10) for write-once recording using a focused 0 , comprising a write-once type L 0 recording layer (3) with an absorption k L0 and a second recording stack (5) named L 1 comprising a write-once type L 1 recording layer (6) with an absorption k L1 . The first recording stack L 0 has an optical reflection value R L0 and an optical transmission value T L0 and the second recording stack has an optical reflection value R L1 . The first recording stack is present at a position closer to the entrance face (8) than the second recording stack. When L0 ‰ 0.75 and 0.40 ‰ R L1 ‰ 0.80 and k L0 < 0.3 and k L1 < 0.3 a dual stack write-once medium is achieved which can be played in a st