Dual-layer phase-change information recording medium and recording and reading method using the same

摘要

The purpose of the present invention is to provide a dual-layer phase-change information recording medium which excels in overwrite properties and allows high-density rewriting even when a blue-violet laser is used. It is a dual-layer phase-change information recording medium containing a first substrate and a second substrate, and a first information layer, an intermediate layer and a second information layer disposed between the first substrate and the second substrate in this sequence, wherein at least any one of recording and reading of information is performed by laser beam irradiation from the first substrate side, the first information layer contains at least a first thermal diffusion layer, a first protective layer, a first recording layer, a second protective layer, a first reflective layer and a second thermal diffusion layer in this sequence, and each thickness of the first protective layer and the second protective layer is 35 nm or less, each thickness of the first thermal diffusion layer and the second thermal diffusion layer is 10 nm or more and the thickness of the first protective layer d₁ (nm) and the thickness of the second protective layer d₂ (nm) satisfy the relation of the next equation, d₁<=D₂+5 nm.