Pioneer Corporation

Yoichi Okumura

Masataka Yamaguchi

Takahiro Togashi

Yasuo Hosoda

Satoshi Jinno

Ayumi Mitsumori

Megumi Sato

Tomoaki Izumi

An information recording medium has an excellent jitter characteristic with a considerable difference in reflectance between prior to and subsequent to recording. The information recording medium includes a recording layer which contains a material having a reflectance which varies by irradiation of a light beam, on which information is recorded as reflectance variations, and a substrate for supporting the recording layer, the recording layer including a metal nitride as a major component. In a method of manufacturing the information recording medium having a recording layer which includes a material having a reflectance which varies by irradiation of a light beam, on which information is recorded as reflectance variations, and the substrate for supporting the recording layer, the recording layer including a metal nitride as a major component, the method includes a recording layer forming step for forming the recording layer by a reactive sputtering method which uses a target comprised of a metal constituting a metal nitride, wherein a flow ratio Ar:Nin an atmosphere including Ar and Nin the recording layer forming step is set within the range of 80:10 to 10:80.

Information recording medium and process for producing the same

A stack '0' having a recording layer serving to transmit a light beam includes a heat dissipating layer, a reflective layer, an enhanced layer, and the recording layer, which are formed in that order on an intermediate layer. The reflective layer is translucent to a light beam, while the heat dissipating layer has a thermal conductivity higher than that of the intermediate layer as well as a refractive index higher than or equal to that of the intermediate layer and less than or equal to a refractive index 3. The thickness of the heat dissipating layer is set to a value within the range of a predetermined condition defined in accordance with a refractive index, the wavelength of the light beam, and a given integer. Thus, an information read/write medium configured to enable information to be recorded/reproduced thereon/therefrom as well as to effectively cool a recording layer serving to transmit a light beam is provided.

Information read/write medium

An information recording medium has a light transmissive layer, a first information recording layer, a transparent layer, and a second information recording layer sequentially stacked to reproduce information signals upon exposure of the light transmissive layer to laser light, wherein the first information recording layer comprises a first protective layer, a phase change recording film, and a second protective layer sequentially from the light transmissive layer, and the rate of power fluctuation between a reproducing light passing through a recorded region of the first information recording layer and that passing through an unrecorded region of the first information recording layer during reproduction of the information signals from the second information recording layer, are within 10%, whereby the information signals can be recorded/reproduced on/from the second information recording layer through the first information recording layer satisfactorily.

Phase-change type optical storage medium having multiple recording layers

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Yamanashi-ken, Japan

Yoichi Okumura