Patent ID: 8018822
Filing Date: 2011-09-13
Classification: G11B

Abstract:
1. An optical information recording medium comprising: a light-transmitting substrate on one of the main surfaces of which pre-grooves are provided circumferentially in an information recording area and dummy grooves other than the pre-grooves are provided circumferentially in an inner peripheral region outside the information recording area and closer to a center hole of the medium than is the information recording area; a recording layer provided on a main surface of the light-transmitting substrate immediately over the pre-grooves, but not over at least some of the dummy grooves; and a reflecting layer provided over the recording layer and immediately over the at least some of the dummy grooves without the recording layer, the surface of the reflecting layer having grooves which reflect the pre-grooves and grooves which reflect the dummy grooves; wherein in the light-transmitting substrate, the pitch of the at least some of the dummy grooves is larger than that of the pre-grooves in the information recording area by a certain degree so as to increase intensity of reflection of visible light from a surface of the reflecting layer having the grooves which reflect the at least some of the dummy grooves.