PURPOSE: To thoroughly prevent the injury of a recording layer from laser light for reading out and to form a recording medium which withstands long- period repeated use by providing a thin inorg. metallic compd. film having high transmittivity to the laser light between a recording layer and synthetic resin substrate.
CONSTITUTION: The thin inorg. metallic compd. film which has high transmittivity to the laser light and has 50W500 to protect the recording layer against the output of the laser light for writing below the threshold value of the recording layer to prevent the injury of the recording layer by the laser light for reading out is provided on the substrate consisting of the synthetic resin and the recording layer is formed on the thin inorg. metallic compd. film. The effect of increasing the threshold value is not enough and the threshold value decreases so that the injury of the recording layer by the output of the laser light for reading out cannot be prevented if the film thickness is ≤50. The recording layer threshold value of the laser light output for writing increases excessively and the formation of pits by the possible output of the semiconductor laser to be used as the laser for writing is not possible if the thickness is ≥500.
TANAKA JUNJI
KATO MASAAKI
OSAWA SHOJI
| JPS52146221A | 1977-12-05 | |||
| JPS5788537A | 1982-06-02 | |||
| JPS57152998A | 1982-09-21 |