US Patent 7976922 Optical recording medium

An optical recording medium including a substrate, an information recording layer including a recording layer and a cover layer, wherein information is written and read on the information recording layer by irradiation of laser beam via the cover layer, the cover layer includes an ultraviolet curing resin and an inner hardness Hi defined as hardness H of the cover layer on a side of the information recording layer satisfies the following relationship: 3.8≦Hi≦5.5, when H=3.8584×F/(h×h), wherein h represents an indented depth in a state in which a triangular pyramid indenter with a tip angle of 115° is pressed under F=9.8 mN.