| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical recording medium of a large capacity which is good in sensitivity, makes a cooling effect obtainable and has an excellent erasing ratio by using an Sb-Te eutectic recording medium material in particular for the phase transition type optical recording medium of a multilayered structure, forming protective layer and heat radiation layers so as to have the thickness and thermal conductivity of a specific relation and controlling the material thicknesses of the respective layers. SOLUTION: The information recording medium having >=2 sets of information recording function layers (information layers) of one set one body having phase transition type recording layers is mainly composed of the multilayered phase transition type information recording medium characterized in that the information layers exclusive of the information layer formed on the deepest side viewed from the surface side on which information carrier light is made incident consist of the first protective layer, recording layer, second protective layer, reflection layer and heat radiation layer in this order and satisfy the following equation when the thicknesses of the second protective layer and the heat radiation layer are respectively defined as d1 and d2 and the thermal conductivity respectively as K1 and K2: 50<=(d2*K2)/(d1*K1)K 1<=K2/2. |
