Erasable optical disk media and method of recording/erasing the same

Abstract

Erasable optical disk media basically comprise a double layer structure composed of a thermal expansion layer formed of an organic dye and a binder, and a retention layer of metal. In the recording process, the thermal expansion layer is heated to form a dome-like pit in the retention layer. The reproducing process is performed by reading differences in reflectivity from the pit and an area surrounding the pit. In the erasing process, the retention layer including the pit is heated to flatten the same under the tensile stress (residual stress) acting on the thermal expansion layer. The pit size is kept in a stable condition during the recording and reproducing processes, while the erasing can be performed completely without leaving partly erased traces. The erasable optical disk media of the foregoing construction are highly durable and resistant to heat.