Optical information recording medium and method for manufacturing same

An optical information recording medium comprising:

• a plural of recording layers, each of which undergoes a change in a refractive index by irradiation with a recording beam;
• and
• a plurality of intermediate layers each provided between adjacent recording layers,
• wherein the recording layers and the intermediate layers have different refractive indices,
• wherein a recording layer has a first interface and a second interface at both sides thereof, the first interface being located at an incident side from which the recording beam enters the recording layer, and the second interface being located at a side opposite to the first interface,
• wherein the recording layer and an intermediate layer are merged with each other at the first interface, whereby a refractive index gradually changes at the first interface, and
• wherein the recording layer and the intermediate layer form a clear interface at the second interface, whereby a refractive index abruptly changes at the second interface, wherein each recording layer has a thickness equal to or greater than 2λ/n, where λ is a wavelength of the recording beam, and n is the refractive index of each recording layer.

An optical information recording medium comprising:

• a plurality of recording layers, each of which undergoes a change in refractive index by irradiation with a recording beam;
• and
• a plurality of intermediate layers each provide between adjacent recording layers,
• wherein the recording layers and the intermediate layers have different refractive indices,
• wherein a recording layer has a first interface and a second interface at both sides thereof, the first interface, being located at an incident side from which the recording beam enters the recording layer, and the second interface being located at a side opposite to the first interface,
• wherein the recording layer and an intermediate layer are merged with each other at the first interface, whereby a refractive index gradually changes at the first interface, and
• wherein the recording layer and the intermediate layer form a clear interface at the second interface, whereby a refractive index abruptly changes at the second interface, which satisfies 0.001<((n2−n1)/(n2+n1))2 <0.04, where n1 is a refractive index of the recording layer, and n2 is a refractive index of the intermediate layer.