Optical information recording medium and its recording and reproducing methods

摘要

A reflectance increasing type optical information recording medium in which the crosstalk is inhibited in the land and groove recording. This optical information recording medium comprises a substrate 1 having a groove 3 and a land 4 provided between adjacent grooves 3, 3 and a recording layer 2 that is provided on the substrate 1 and that changes the reflectance by irradiation with light beams. In this recording medium, the reflectance after recording is greater than the reflectance before recording. Moreover, the depth D of the groove 3 is set to be in the range of lambda /8n to 3 lambda /8n, where the wavelength of the light beam is lambda and the refractive index of the substrate is n. And the difference, DELTA phi = phi 1 - phi 0, between the phase phi 1 of the reflected light after recording and the phase phi 0 of the reflected light before recording is in the range of (-0.1 + 2 m) pi to (0.1 + 2 m) pi , where m is an integer. <IMAGE>