OPTICAL INFORMATION RECORDING MEDIUM AND ITS RECORDING/ REPRODUCING METHOD

摘要

PROBLEM TO BE SOLVED: To provide an optical information recording medium of a reflectance increase type capable of recording high density information and less in a cross talk in land/groove recording. SOLUTION: In a recording medium provided with a groove 3, a substrate 1 having a land 4 between the adjacent grooves and a recording layer 2 provided on the substrate 1 and changing its reflectance by irradiation of a light beam, the medium is set so that the reflectance after recording becomes larger than the reflectance before recording, the depth D of the groove 3 becomes within the range of >=λ/8n and <=3λ/8n when the wavelength of the light beam is defined λ and the refractive index of the substrate 1 is (n), and a difference Δϕ=ϕ1 -ϕ0 between the phase ϕ1 of reflection light after recording and the phase ϕ0 of the reflection light before recording becomes within the range of >=(-0.1+2m)π and <=(0.1+2m)π (where, m is an integer).