Optical information recording medium

An optical information recording medium for recording and erasing information by irradiation with a recording and erasing beam and for reproducing information by irradiation with a reproducing beam having a different wavelength from the recording and erasing beam, the optical information recording medium comprising:

• a substrate having an irradiation surface on which the recording and erasing beam and the reproducing beam are incident;
• a transparent interference layer provided on the substrate on a side opposite to the irradiation surface and having a first surface facing the substrate and a second surface opposite to the first surface;
• and
• a recording layer provided on the transparent interference layer on an opposite side of the substrate with respect to the transparent interference layer and having a third surface facing the second surface of the transparent interference layer, wherein the recording layer undergoes a phase change between a crystalline phase and an amorphous phase to vary a reflectance thereof of the irradiation of the recording and erasing beam,
• wherein first, second and third beams are beams reflected from the first, second, and third surfaces of the transparent interference layer and the recording layer, respectively, in accordance with irradiation of the beam,
• the first, second and third beams are substantially in-phase with each other with respect to the reproducing beam perpendicularly entering the irradiation surface of the substrate;
• and
• the second and third beams are substantially in-phase with each other and the first beam is substantially in an anti-phase relation to the second and third beams with respect to the erasing and recording beam perpendicularly entering the irradiation surface of the substrate.

An optical information recording medium for recording, erasing, and reproducing information by being irradiated with a beam, the optical information recording medium comprising:

• a substrate having an irradiation surface on which the beam is incident;
• an optical interference stack provided on the substrate on a side opposite to the irradiation surface and including a first interference layer and a second interference layer having a light transmittance that is smaller than that of the first interference layer;
• a first protection layer provided on the optical interference layer;
• a recording layer provided on the first protection layer which undergoes a phase change by the irradiation of the beam to record and erase the information therein and therefrom;
• and
• a second protection layer provided on the recording layer,
• wherein the beam includes a first beam for recording and erasing the information by causing the phase change to the recording layer and a second beam for reproducing the information recorded in the recording layer, the second beam having a wavelength that is different from that of the first beam, and
• wherein the first interference layer has different reflectances with respect to the first and second beams.