OPTICAL INFORMATION RECORDING MEDIUM

摘要

An optical information recording medium for recording and reproducing information by irradiation with a laser beam having a wavelength lambda of 450 nm or less includes a substrate 14 and a plurality of information layers formed on the substrate. A first information layer 8 closest to an incident side of the laser beam among the plurality of information layers includes a recording layer 4, a reflection layer 6 and a transmittance adjusting layer 7. A transmittance Tc1 (%) of the first information layer 8 at the wavelength lambda in a case of the recording layer 4 in a crystal phase and a transmittance Ta1 (%) of the first information layer 8 at the wavelength lambda in a case of the recording layer 4 in an amorphous phase satisfy 46 < Tc1 and 46 < Ta1. Furthermore, a refractive index n1 and an extinction coefficient k1 of the transmittance adjusting layer 7 at the wavelength lambda , and a refractive index n2 and an extinction coefficient k2 of the reflection layer 6 at the wavelength lambda satisfy 1.5≤(n1 - n2) and 1.5≤(k2 - k1).