Patent ID: 7431973
Filing Date: 2008-10-07
Classification: G11B,Y10T

Abstract:
1. An optical information recording medium comprising: a transparent substrate; and at least one recording layer disposed on the transparent substrate, the recording layer including at least a first phase-changeable film and a second phase-changeable film, with the first phase-changeable film being disposed closer to the transparent substrate than the second phase-changeable film, and the first phase-changeable film and the second phase-changeable film being in contact with each other, each of the first phase-changeable film and the second phase-changeable film containing at least 10 atom % and no more than 50 atom % germanium and at least 45 atom % and no more than 60 atom % tellurium, wherein either (1) only one of the first and second phase-changeable films contains bismuth, or (2) each of the first and second phase-changeable films contains bismuth such that an amount of bismuth contained in the first phase-changeable film is different from an amount of bismuth contained in the second phase-changeable film.