| 摘要 |
PURPOSE:To obtain a rewritable optical disk having a simple constitution. CONSTITUTION:A recording layer 4 of a single layer structure is formed, on a transparent substrate 1. This recording layer consists of a polyurethane shape- memory resin which shows reduction of elasticity at higher temp. than the temp. range of room temp. and contains an absorbent for light consisting of a Ni complex or diimonium compd., and the layer has >=0.8mum thickness and <30% transmittance of light. Since the Ni complex or diimonium compd. having high melting point and durability against heating by irradiation of laser light is used as the light absorbent (dyestuff) the temp. range for erasing conditions that is higher than Ts but lower than the decomposition temp. of the dyestuff can be widely obtd. Times for possible rewriting is significantly improved though an org. material used for the medium. By forming the single-layer recording layer 4 having >=0.8mum thickness and <=30% transmittance of light, a medium of high C/N can be easily. obtd., and further, good erasing rate for the line speed for recording can be obtd. |
