Information recording medium and information recording and reproducing method and apparatus.

摘要

An information recording medium (32) which comprises two or more energy beam absorbing layers (2, 4) which are formed at different positions across the thickness within the depth of focus of the energy beam, and an energy beam transmitting layer (3) interposed between said energy beam absorbing layers (2, 4). A method for recording and reproducing information by applying an energy beam to an information recording medium (32) mentioned above, characterized in that the information recording is accomplished in response to the energy beam power which varies or the pulse waveform which varies, or both. An apparatus for reproducing information which comprises a means (30) to encode information into recording signals and a means (31) to drive the irradiating energy beam. The information recording medium (32) has a high recording density and a large recording capacity owing to its capability of multi-valued recording.