| 摘要 |
PURPOSE:To obtain three states in response to the irradiation of light and to increase the quantity of information that can be recorded, by laminating a dielectric layer, a record layer, a dielectric layer and a record layer successively on a reflection layer containing a metallic surface formed on a substrate and using a material which forms holes with irradiation of light to the record layer. CONSTITUTION:A recording medium is formed by laminating successively a reflection layer 8 of Al, etc., a dielectric layer 7, and 5 of SiO2, etc. and record layers 4 and 6 made of a material such as Te, etc. which forms holes with irradiation of light. The information is written to the layers 4 and 6 by forming holes with irradiation of light. In this case, the light having intensity higher than the threshold value is needed. The layer 6 has higher threshold value than the layer 4. Therefore the holes are formed only to the layer 4 by the intensity of the light to be irradiated. Otherwise the holes are formed to both layers 4 and 6. Thus the information can be recorded in three states. |
