| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical information recording medium which can prevent warpage due to temperature and humidity change and can be easily manufactured. <P>SOLUTION: Thickness of a transparent substrate 20 is thinner than 1.2 mm, and thickness of substrate protective film 30 is thinner than a thin film protective film 50. When the cross section of the optical information recording medium for recording and reproducing is replaced with laminated n-layers, an approximated value of the warpage angle change of the laminated n-layers, which is obtained by substituting each of physical properties when the temperature change T is imposed to the optical information recording medium and then the warpage angle change takes a steady-state value into each parameter corresponding to equation 1 to 5 and by setting position y to be t1+t2≤y≤t1+t2+t3, becomes equal to or less than 1 mrad so that at least either Young's modulus or linear coefficient of expansion of the thin film protective film 50 becomes larger than either one of the transparent substrate 20. <P>COPYRIGHT: (C)2007,JPO&INPIT |
