Phase change recording medium for allowing a tracking servo control based on a differential phase detection tracking method

摘要

An erasable phase change recording medium includes a transparent substrate (10a), a recording layer (10c) of a phase change material provided on the substrate, and a protection layer (10b,10d) provided to protect the recording layer on the substrate. Tracks are formed with alternate grooves and lands on the substrate of the recording medium and data is recorded to at least one of the grooves and the lands. The recording medium is configured to have a track pitch between 0.6 mu m and 0.8 mu m and a groove depth between 0.11.L and 0.18.L where L is a wavelength of a laser beam. A heat radiation layer (10e) is deposited on the upper protection layer (10d).