OPTICAL INFORMATION RECORDING MEDIUM AND RECORDING/REPRODUCING METHOD THEREFOR

摘要

An optical information recording medium which comprises a first substrate, a second substrate and a recording layer formed between the first and second substrates, and which has land units and groove units formed thereon, wherein a distance between a light source of a laser beam irradiating the optical information recording medium and the land units is larger than that between the light source and the groove units, the land units are formed on the optical information recording medium at a pitch of up to 0.40 mu m and carry either one of a first state having a first reflectance and a second state having a second reflectance lower than the first reflectance, the first and second states being capable of reversibly being changed over by a laser beam irradiation, and the difference phi 1- phi 2 between the phase phi 1 of reflection light from a portion in the first state of the land units and the phase phi 2 of reflection light from a portion in the second state satisfies 2n pi