RECORDING-REPRODUCING METHOD FOR OPTICAL INFORMATION RECORDING MEDIUM AND RECORDING-REPRODUCING EQUIPMENT

摘要

PROBLEM TO BE SOLVED: To provide a recording-reproducing method for an optical information recording medium by which information recorded in an optical recording medium comprising a photochromic material can be reproduced without erasing or overwriting the information and to provide a recording and reproducing equipment. SOLUTION: Information recorded in an information recording medium 21 using a photochromic material in a recording layer 7 by making use of the state change of ring opening or ring closure of the photochromic material by irradiating the medium 21 with recording light having a specified wavelength which contributes to ring opening or ring closure of the photochromic material is reproduced with reproduction light having a wavelength different form that of the recording light by detecting a small refractive index change caused in accordance with the state change of ring opening or ring closure of the photochromic material by a difference in the wave guide mode of the reproduction light.