Optical recording medium

摘要

A disc-shaped recording medium (40) having transcription characteristics for fine signals simultaneously with resonance characteristics and stiffness which are characteristics contrary to the transcription characteristics. At least a recording layer (42) and a light transmitting layer (41) are sequentially formed on a substrate (44,45) and light (L) is illuminated from a light transmitting layer (41) side to record and/or reproduce information signals. The substrate includes a core layer (45) formed of a resin composition comprised of a mixture of two or more resin sorts. The resin composition has tan delta , as an index indicating the internal loss, equal to not less than 0.015 as a system in its entirety. The resin composition constituting the core layer (45) is a compounded resin of the incompatible system and is of an islands-sea structure.