| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical information recording medium causing no deterioration of writing and reading characteristics after preservation over an extended period of time and having high reliability. <P>SOLUTION: (1) In the optical information recording medium which includes a substrate, an information recording layer including a recording layer and a cover layer and wherein information is written and read on the information recording layer by irradiation with a 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. (2) In the optical recording medium described in (1), the optical curing resin comprises 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1-on as an optical polymerization initiator. <P>COPYRIGHT: (C)2008,JPO&INPIT |
