Optical information recording medium and method for producing the same, method for recording and reproducing information thereon and recording/reproducing apparatus

Abstract

An optical information recording medium of the present invention includes a transparent substrate and a multi-layered film formed on the transparent substrate. The multi-layered film includes a lower protective layer, a recording layer that changes reversibly between different states detectable optically by irradiation of light beams, an upper protective layer, an intermediate layer and a reflective layer in this order from the side near the transparent substrate. Of the upper protective layer, the intermediate layer and the reflective layer, the heat conductivity of the layer closest to the recording layer is the smallest of the three layers, and thereafter the heat conductivities of the others increase with increasing the distance from the recording layer, and the thickness of the recording layer is from 4 nm to 16 nm. In addition, a light absorption layer can be used in place of the intermediate layer. In this case, the difference between the refractive index of the light absorption layer and the refractive index of the reflective layer is 2 to 6, and the thickness of the reflective layer is not smaller than the thickness of the light absorption layer. Alternatively, the light absorption layer has a thickness d, in a range of 0.1 &lgr;/(n,·k,)≦d,≦1.0 &lgr;/(n,·k,), where n,is a refractive index and k,is an extinction coefficient of the light absorption layer.