Abstract: An optical thin film provided on a base substrate, includes a layer whose main component is ytterbium oxide, and a layer whose main component is magnesium fluoride. The layer whose main component is magnesium fluoride disposed on the layer whose main component is ytterbium oxide. The layer whose main component is magnesium fluoride is positioned opposite from the base substrate with respect to the layer whose main component is ytterbium oxide.

Abstract: An optical thin film provided on a base substrate, includes a layer whose main component is ytterbium oxide, and a layer whose main component is magnesium fluoride. The layer whose main component is magnesium fluoride disposed on the layer whose main component is ytterbium oxide. The layer whose main component is magnesium fluoride is positioned opposite from the base substrate with respect to the layer whose main component is ytterbium oxide.

Abstract: An optical information recording medium is composed of at least a phase-change type recording layer 4 provided on a substrate 1. The optical information recording medium is conducted to record and erase information by changing a phase of the phase-change type recording layer by irradiating light. The phase-change type recording layer is further composed of TiwGexSbyTez, wherein each of w, x, y and z is in atomic percent and satisfies following relations: 0.5?w?4.0, 3.4?x?14.5, 2.1?y/z?4.0 and w+x+y+z=100.

Abstract: An optical information recording medium 10 is composed of at least a reflective layer 2, a first protective layer 3, a phase-change type optical recording layer 4 and a second protective layer 5 being sequentially laminated on a substrate 1. The optical information recording medium 10 is conducted to record information by changing a phase of the phase-change type optical recording layer 4 by irradiating light from the second protective layer 5 side. The phase-change type optical recording layer 4 further contains at least Ti, In, Ge, Sb and Te. When each content amount of the Ti, In, Ge, Sb and Te is defined as v, w, x, y and z in atomic percent respectively, each content amount of v, w, x, y and z in atomic percent satisfies following relations: 0.3?v?4, 0.3?w?3, 3.4?x?14.5, 2.1?y/z?4 and 98.8?v+w+x+y+z?100.?.

Abstract: An optical information recording medium 10 is composed of at least a reflective layer 2, a first protective layer 3, a phase-change type optical recording layer 4 and a second protective layer 5 being sequentially laminated on a substrate 1. The optical information recording medium 10 is conducted to record information by changing a phase of the phase-change type optical recording layer 4 by irradiating light from the second protective layer 5 side. The phase-change type optical recording layer 4 further contains at least Ti, In, Ge, Sb and Te. When each content amount of the Ti, In, Ge, Sb and Te is defined as v, w, x, y and z in atomic percent respectively, each content amount of v, w, x, y and z in atomic percent satisfies following relations: 0.3≦v≦4, 0.3≦w≦3, 3.4≦x≦14.5, 2.1≦y/z≦4 and v+w+x+y+z≦100.

Abstract: An optical information recording medium is composed of at least a phase-change type recording layer 4 provided on a substrate 1. The optical information recording medium is conducted to record and erase information by changing a phase of the phase-change type recording layer by irradiating light. The phase-change type recording layer is further composed of TiwGexSbyTez, wherein each of w, x, y and z is in atomic percent and satisfies following relations: 0.5≦w≦4.0, 3.4≦x≦14.5, 2.1≦y/z≦4.0 and w+x+y+z=100.

Abstract: A manufacturing method of an optical disc 16 is composed of a first process of forming at least a first recording layer 5 over a first embossed pit 2 of a first substrate 1, a second process of forming at least a separative layer 9 and a second recording layer 11 sequentially over a second embossed pit 8 of a second substrate 7 having light transmittability, a third process of laminating the second substrate 7 over the first substrate 1 after coating an ultraviolet curable resin 14 over the first recording layer 5 and facing the second recording layer 11 toward the ultraviolet curable resin 14, and hardening the ultraviolet curable resin 14 by irradiating an ultraviolet ray on the ultraviolet curable resin 14 through the second substrate 7, a fourth process of transferring the second recording layer 11 over the first recording layer 5 by separating the second substrate 7 from the first substrate 1 together with the separative layer 9, and a fifth process of forming a thin cover layer 15 having light transmitt