Patent ID: 7065035

Claim:
An optical information recording medium, with respect to which recording and reproduction are performed with laser beams from one side, comprising at least two recording layers formed of a phase change material on a substrate, wherein the recording layers include a first recording layer and a second recording layer in the order from the side on which the laser beams are incident, the first recording layer is included in a first recording medium and the second recording layer is included in a second recording medium, when a wavelength of a first laser beam with which recording and reproduction are performed with respect to the first recording medium is indicated as λ1 (nm), a wavelength of a second laser beam with which the second recording medium is recorded and reproduced as λ2 (nm), a light absorptance of the first recording layer in a crystal state as Ac (%), a light absorptance of the first recording layer in an amorphous state as Aa (%), a light transmittance of the first recording medium with the first recording layer being in the crystal state as Tc (%), a light transmittance of the first recording medium with the first recording layer being in the amorphous state as Ta (%), and the relationship between the wavelength λ1 and the wavelength λ2 is expressed by 10≦|λ1−λ2|≦120, the first recording layer has a light absorption ratio Ac/Aa in a predetermined range with respect to the wavelength λ1 and the first recording medium satisfies conditions of Tc≧30 and Ta≧30 with respect to the wavelength λ2, wherein the first recording medium and the second recording medium are separated by a distance in the range between 1 μm and 50 μm, wherein the first recording layer has a thickness of d2 (nm) in a range of 3≦d2≦9, and wherein the first recording medium includes at least the recording layer and a reflective layer formed sequentially on the substrate, and the reflective layer has a thickness d3 (nm) in a rage of 2≦d3≦20.