Importance

Loading Importance Indicators...

Abstract

A phase change optical recording medium having an increased number of overwritable operations is provided. In this medium, the recording layer is disposed between a first dielectric layer and a second dielectric layer which contain zinc sulfide and silicon oxide as their main components; and difference between light absorption coefficient (Ac) of the recording layer in the region other than record marks (in crystalline state) and the light absorption coefficient (Aa) of the recording layer in the record marks (in noncrystalline state) is small, or Ac>Aa. More illustratively, the first dielectric layer is disposed underneath the recording layer and the second dielectric layer is disposed over the recording layer; and the conditions: Ac/Aa.gtoreq.0.9 and/or light transmittance .gtoreq.1% is satisfied. The first dielectric layer comprises a dielectric layer 1a on the side of the substrate and a dielectric layer 1b on the side of the recording layer; and the dielectric layer 1a has a silicon oxide content of from 2 mol % to less than 40 mol %, the dielectric layer 1b has a silicon oxide content of from 40 mol % to 80 mol %, and the second dielectric layer has a silicon oxide content of from 40 mol % to 80 mol %; and the second dielectric layer has a thickness of 10 to 35 nm.

Loading the Abstract Image...

First Claim