| 摘要 |
PURPOSE:To prevent the destruction of information, by forming the 2nd recording film different from the 1st recording film having a long life in composition on part of an optical information recording medium and by detecting the deterioration degree of the 2nd film to previously detect the deterioration of the 1st film. CONSTITUTION:The 1st information recording film 2 having a long life is formed on a disklike substrate 1 of glass, acrylic resin or the like. The film 2 is made of a Te alloy contg. >=5wt% Se for improving the oxidation inhibiting property such as Te-Se, Pb-Te-Se, In-Te-Se or As-Te-Se, and the shape of pits after optical recording has been regulated with Pb, In, As or the like to prevent the cracking of the film. The 2nd recording film 3 or Te of Te-Se contg. <=5% Se is formed on part of the substrate 1 close to the central hole. The progress of the oxidation of the film 2 is exactly detected by measuring the transmittance and reflectance of the film 3, and the destruction of the information can be prevented by recording the information on a fresh recording medium before the film 2 is deteriorated. |
