Patent ID: 7263707

Claim:
An information processing medium comprising a substrate, a single layered or multilayered thin film layer formed on the substrate, and a thin protective film formed to cover at least on surface of the thin film layer, wherein the thin protective film is mainly comprised of a synthetic resin, and at least either one of a Young's modulus and a linear expansion coefficient of the thin protective film has a value compensating a radial skew variation of the substrate caused by a change in ambient conditions, wherein an expansion coefficient β under humidity of the thin protective film (ratio of expansion (1%) of the thin film protective film where a difference of relative humidity (vapor content/saturated vapor amount at 25° C.) is increased by 1%) is β≦2.0×2.0×10 −14 ×E 1 +3.0×10 −5 , wherein the Young's modulus of the substrate is given as E 1 (Pa).