Patent ID: 8031574

Claim:
An information recording medium onto which information is to be recorded and/or from which information is to be reproduced using a laser beam, the information recording medium comprising: a first information recording layer formed at a laser beam entrance surface of the medium and configured so that information can be recorded thereupon and/or reproduced therefrom using near-field light with a first objective lens having a first numerical aperture NA 1 (NA 1 ≧0.9) and laser beam of a first wavelength λ 1 ; and a second information recording layer formed so as to have a distance to the laser beam entrance surface of 0.05 mm to 1.2 mm and configured so that information can be recorded thereupon and/or reproduced therefrom using a second objective lens having a second numerical aperture NA 2 (NA 2 <0.9) and laser beam of a second wavelength λ 2 , wherein: when a diffraction limit δ 2 , determined by the numerical aperture NA 2 and the second wavelength λ 2 , is taken as δ 2 =0.61×λ 2 /NA 2 , a track pitch Tp 1 of a track formed on the first information recording layer is Tp 1 <δ 2 ; the distance from the second information recording layer to the laser beam entrance surface is set in a range of 0.06 mm to 0.11 mm; an amount of data recorded onto the first information recording layer and the second information recording layer is no more than 25 Gbyte for each of the layers; and the second information recording layer is single-layer.