Patent ID: 7283458

Claim:
An optical information recording medium in which light is projected in a spot to thereby record/reproduce information and in which at least a recording layer and a light-transmitting layer are disposed in this order on a substrate having a guide groove for tracking of the spotted light and in which the light is projected in the spot to the recording layer from the side of the light-transmitting layer to record the information both in a first portion of the recording layer corresponding to the inside of the guide groove and a second portion of the recording layer corresponding to a flat portion between mutually adjacent guide grooves, wherein assuming that a wavelength of the light is λ, and an index of refraction of the light-transmitting layer in the wavelength λ is nf, a depth d of the first portion with respect to the second portion in the surface of the recording layer on the side of the light-transmitting layer satisfies a relation of λ/5.8 nf £ d £ λ/5 nf, and a reflectance of the recording layer after the recording is larger than that before the recording.