Phase Change Disc for High Data Rate Recording

Abstract

We have developed a phase change disc having a thin transparent cover layer corresponding to the new optical recording system (DVR) using a blue laser (405 nm) and a numerical aperture (NA) of 0.85. We have achieved a user capacity of 22 GB per side of the 120 mm diameter disc, and a user data recording rate of 70 Mbps by designing a highly flat transparent cover layer, a recording layer having high crystallization speed and a film structure for rapid cooling.