RECORDING AND ERASING METHOD OF OPTICAL INFORMATION

摘要

PURPOSE:To ensure a whitening record and erasion of a whitening record area after blackening for an optical and thermal information recording member that can carry out a recording with a lowering of the optical density after a rise of temperature by heating and then a quenching. CONSTITUTION:A recording thin film 3 is formed with an evaporated thin film of chalcogen compound or a low oxide thin film on an heat-resistant base material 2 and receives a heat treatment up to a saturation blackening level to be changed into a black disk. The cooling speed after a rise of temperature by heating becomes high with a short pulse duration and then becomes low with a long pulse duration since the temperature does not lower easily due to a rise of temperature of the whole base material. A quenching and whitening state is obtained with the pulse duration from 10nsec to several musec; and a blackening state is obtained with the pulse duration of >=10musec, respectively. A signal recording is carried out by a means that selects a small value of the irradiation time of light which is decided by the size of the light beam spot and the relative transfer speed of a blackening record film that is due to the rotation of the disk.