Patent ID: 8216655

Claim:
An optical information recording medium comprising: a supporting substrate; a light-transmissive protective layer disposed at a side of the optical information recording medium on which a recording/reproducing laser beam is incident; a plurality of information recording layers; and at least one interlayer which is transparent to the recording/reproducing laser beam having a wavelength in the range of 400 to 410 nm, and each interlayer is disposed between adjacent information recording layers, the information recording layers and the at least one interlayer being disposed between the supporting substrate and the light-transmissive protective layer, wherein, among the plurality of information recording layers, one or a plurality of information recording layers other than the information recording layer closest to the supporting substrate each function as a semi-transmissive information recording layer that transmits the laser beam, and some or all of the one or the plurality of semi-transmissive information recording layers have a structure including a first dielectric portion having a refractive index of 2.4 or more for the wavelength of the recording/reproducing laser beam, a recording material portion having a thickness of at least 5.2 nm, a second dielectric portion, a metal portion having a thickness of at least 7 nm, and a third dielectric portion sequentially laminated in that order from the incident side of the laser beam.