Patent ID: 7123551

Claim:
An optical device comprising: a light source; an optical recording medium; an optical system focusing light from the light source to the optical recording medium; the optical recording medium comprising, a substrate; a metal reflective layer formed on the substrate; a first protective layer of Zn—SiO 2 formed on the metal reflective layer; a recording layer formed on the first protective layer, the recording layer being made of a material undergoing a phase change and configured to change a complex index of refraction under said light; a second protective layer of Zn—SiO 2 formed on the recording layer; and the transparent heat radiating layer formed on the second protective layer and having a heat conductivity higher than the second protective layer so as to disperse heat from the recording layer, wherein the transparent heat radiating layer is a multi-layer film comprising a plurality of layers stacked together, having substantially same optical constants and having different heat constants; and light is focused from the optical system to the recording layer via a side of the optical recording medium closer to the heat radiating layer than to the substrate, wherein said optical recording medium is used in a near field condition.