Optical information recording medium with thermal diffusion layer

Abstract

An optical information recording medium is provided in which recording can be performed at higher speed with higher density by enabling the cooling power of the recording medium to be improved, the overwritten-mark distortion to be decreased, and an medium with high transmittance to be obtained. The optical information recording medium is formed by laminating, sequentially on a substrate: a protective layer; an interface layer; a recording layer whose optical characteristics are varied reversibly by irradiation of a laser beam; an interface layer; a light transmittance type reflective layer that transmits the laser beam with a wavelength λ; and a thermal diffusion layer. A thickness d of the thermal diffusion layer is set to be within a range of 0<d≦({fraction (5/16)})λ/n or ({fraction (7/16)})λ/n≦d≦(½)λ/n, wherein n indicates a refractive index of the thermal diffusion layer.

Dependencies are inferred from the claim text.