US Patent 7542406 Optical information recording medium

An optical information recording medium includes a substrate having a pregroove thereon, an optical recording layer containing a light-absorbing substance composed of a dye absorbing a laser beam, and a light-reflective layer reflecting the laser beam. The ratio of the cross-sectional area of the optical recording layer (i.e., the dye) in the pregroove to the cross-sectional area of the pregroove in the direction of the diameter of the optical information recording medium is about 30% to about 63%. In the optical information recording medium, the phenomenon by which the recording power of the laser beam heats the dye in the optical recording layer and the heat is diffused through the optical recording layer and the light-reflective layer is considered.