Patent ID: 7477592

Claim:
A single-sided dual layer optical disc comprising: a light transmission layer; a translucent first recording layer which is accessed with a first laser beam; an space layer; and a second recording layer which is accessed with a second laser beam, these layers being arranged in that order in the direction in which a laser beam enters, the areal recording density of the second recording layer being three times or more as high as that of the first recording layer, identifying information to indicate that the first recording layer has been formed being formed in the second recording layer, the thickness of the light transmission layer from an incidence plane to the first recording layer being 550 μm or more, the thickness of the light transmission layer from the incidence plane to the second recording layer being 622 μm or less, the reflectivity of the first recording layer with respect to the first laser beam being 45% to 65%, and the reflectivity of the second recording layer with respect to the second laser beam being 15% to 29%.