| 摘要 |
PURPOSE:To obtain the reloadable optical recording medium which can stably and surely reproduce tracking information. CONSTITUTION:A thin layer 3 of a hard material having the refractive index higher than the refractive index of a transparent substrate 1 having guide grooves 2 is provided on the surface of the substrate 1 and a recording layer 4 consisting of single layer constitution constituted by incorporating a light absorbent into a thermosetting polyurethane resin, the modulus of elasticity of which degrades at the temp. higher than the temp. range of room temp. is provided on the thin layer 3. The recording light entering from the substrate 1 side is passed through the recording layer 4 so that recording bits in the state of build-up parts are easily generated on the side opposite from the substrate 1 by the thermal expansion of the recording layer. The thickness of the thin layer 3 provided on the surface of the substrate 1 does not change regardless of the presence or absence of the recording bits and, therefore, the thin layer is helpful for generating the reflected light including the always good tracking information. The recording layer is heated by irradiation with continuous light from the substrate side 1 and is slowly cooled, by the recording layer is flattened and the erasing of the recording information is well executed. |
