| 摘要 |
PURPOSE:To prevent or suppress the chemical reaction of a thin film layer and corrosive elements and to obtain the optical information recording medium having excellent corrosion resistance and a long life by forming a substrate by using a polycarbonate resin contg. the corrosive element at a specific ratio or below. CONSTITUTION:The thin film layer 1 is formed of the polycarbonate resin adjusted to <=35ppm content of the corrosive elements and a recording layer or reflecting layer 3 is laminated on one face thereof. Pregrooves 4 for guiding radiation beams for recording or reproducing along recording tracks and prepits 5 where address signals are subjected to signal modulation are provided on the signal pattern forming surface. Since the total content of the corrosive elements incorporated into the substrate 1 is low, the chemical reaction of the thin film layer 3 and the corrosive elements does not take place even when the medium is rested in a high-temp. and high-humidity atmosphere. The rate of progression of the reaction is low even if such reaction takes place. The recording medium having the excellent corrosion resistance and the long life is thereby obtd. |
