OPTICAL RECORDING MEDIUM

摘要

PURPOSE:To optically record or erase information by using an alloy material having allotropic transformation entailing surface undulation as a recording medium and subjecting the same to a heat treatment by irradiation of a light beam to generate the allotropic transformation and making use of the difference in the reflectivity of light between both phases. CONSTITUTION:Targets are manufactured of Co-Pd, Co-Ni or Co-Cu alloys which are respectively varied in compsn. A thin film as the recording medium 1 is formed on a disk-shaped quartz substrate 2 provided with guide grooves by using such alloys as the target. The thin recording film is of a hexagonal crystal phase and the surface of the thin film is finely undulated but the medium surface of the part irradiated with laser light is in the smooth state. The recorded information is thus easily reproduced by detecting the reflectivity of the light on the medium surface.