| 摘要 |
An optical information-recording medium includes a substrate, and a lower protective layer, a recording layer, an upper protective layer, and a reflective layer, formed on the substrate. The recording layer exhibits different optical properties dependent on different thermal histories of a rise and a fall in temperature caused by irradiation of a laser beam on the substrate. The optical information-recording medium has a layer structure constructed such that reflectivity of the optical information-recording medium and the phase of light reflected therefrom vary with the change in the optical properties of the recording layer, with absorptivity of light of the recording layer being larger when the recording layer is in a crystalline state than when the recording layer is in an amorphous state, and at the same time, reflectivity exhibited when the recording layer in the crystalline state being 10% or higher. The reflective layer has a thickness set such that a value of reflectivity of the reflective layer exhibited in the form of a single layer is 90% or more of a value of reflectivity of a bulk form of a substance of the reflective layer, or to a value of 40 nm or larger.
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