Optical recording medium having substrate of dual transparent layers

Abstract

Disclosed is an information recording medium capable of, in the case of recording information signals such as high density information, sufficiently transferring the information signals, and suppressing resonance upon high speed rotation and enhancing the durability of the medium. The medium includes a substrate, a recording layer provided on the substrate for recording an information signal, and a light transmission layer laminated on the recording layer, wherein an information signal is recorded or reproduced on or from the medium by making light incident on the medium from the light transmission layer side. The substrate includes a core layer made from a resin, and a surface layer made from a resin and integrated with the core layer. The surface layer has on its one side plane information signals in the form of irregularities on the recording layer side and has a fluidity which is larger than that of the core layer in the case where both the surface layer and the core layer are in a molten state at the same temperature.