Kabushiki Kaisha Toshiba

Noritake Ohmachi

Naomasa Nakamura

Katsutaro Ichihara

Keiichiro Yusu

Sumio Ashida

Takayuki Tsukamoto

Nobuhisa Yoshida

A phase-change optical recording medium includes a phase-change optical recording film that permits reversible phase change between a crystalline phase and an amorphous phase upon irradiation with light, and an interface film formed of hafnium oxide, or a mixture of hafnium oxide and at least one oxide selected from the group consisting of cerium oxide, titanium oxide and zirconium oxide, and formed in contact with at least one surface of the phase-change optical recording film.

Phase-change optical recording medium

There is provided an optical recording medium capable of preventing cross erase and increasing its recording density. The optical recording medium includes: a reflecting film; a first transparent film provided on the reflecting film; a first semitransparent film provided on the first transparent film; a second transparent film provided on the first semitransparent film; a recording film provided on the second transparent film, the recording film being capable of reversibly changing an atomic arrangement; and a third transparent film provided on the recording film. The first semitransparent film has a complex refractive index of n&#x2212;ik satisfying relationships of 0&#x3c;n&#x3c;1 and 1&#x3c;k, and a product of a thickness d (nm) of the first semitransparent film and an extinction coefficient k of the complex refractive index is d&#xd7;k&#x2266;44.

Optical recording medium

There is provided an optical recording medium capable of preventing cross erase and increasing its recording density. The optical recording medium includes: a reflecting film; a first transparent film provided on the reflecting film; a first semitransparent film provided on the first transparent film; a second transparent film provided on the first semitransparent film; a recording film provided on the second transparent film, the recording film being capable of reversibly changing an atomic arrangement; and a third transparent film provided on the recording film. The first semitransparent film has a complex refractive index of n&minus;k satisfying relationships of 0<n<1 and 1<k, and a product of a thickness d (nm) of the first semitransparent film and an extinction coefficient k of the complex refractive index is d&times;k&lE;44.

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Yokohama, Japan

Noritake Ohmachi