Abstract: A multilayer optical recording medium including at least multiple information layers having at least a phase change recording layer capable of recording information by laser irradiation and a reflection layer, wherein information layer as seen from a side of the laser irradiation has at least a lower protection layer, the phase change recording layer, an upper protection layer, the reflection layer and an optical transmission layer, the upper protection layer and the optical transmission layer in each information layer other than the innermost one are composed of an Sn oxide-containing material and a thickness of the upper protection layer in each information layer other than the innermost one as seen from the side of the laser irradiation is 2 nm to 15 nm is provided.

Abstract: An optical information recording medium comprising a substrate, recording layer and reflecting layer, characterized in that a layer containing a mixture of carbide and oxide is disposed over a surface of the reflecting layer which faces to the recording layer. The carbide is a carbide of at least one metal selected from Ti, Zr, V, Nb, Ta, Cr, Mo and W, and the oxide is an oxide of at least one metal selected from Ti, Zr, V, Nb, Ta, Cr, Mo and W.

Abstract: A two-layered optical recording medium which includes a first substrate, a first information layer, a second information layer, and a second substrate formed in this order as viewed from the light beam irradiation side, the first information layer includes a first lower dielectric layer, a first recording layer, a first upper dielectric layer, a first reflective layer, and an inorganic dielectric layer formed in this order as viewed from the light beam irradiation side; the second information layer includes a second lower dielectric layer, a second recording layer, a second upper dielectric layer, and a second reflective layer formed in this order as viewed from the light beam irradiation side; and the first reflective layer is made of Cu with a content of 99.8% by mass to 95.0% by mass and one or more metals selected from Ta, Nb, Zr, Ni, Cr, Ge, Au, and Mo.

Abstract: The present invention is to provide a practically usable, recordable or rewritable optical information recording medium having a pair of recording layers and a recording and reproducing apparatus for the medium. The recording medium has a pair of recording layer structures on a substrate so as to sandwich a resin intermediate layer, and a recording beam and a reproducing beam are irradiated to two recording layer structures. The pair of recording layer structures respectively have a different track pitch, and the ratio of difference in the track pitch defined by Expression 1 is +0.03 to +0.15, (T2?T1)/T1 ??Expression 1 T1 represents a track pitch of the recording layer structure disposed on the laser beam irradiation side, and T2 represents a track pitch of the recording layer structure disposed on the inner side.

Abstract: A multilayer phase change information recording medium including plural information layers containing at least a first information layer and a last information layer, each of which includes a recording layer in which information is recorded utilizing a phase change between a crystalline phase and an amorphous phase. At least one of the plural information layers other than the last information layer includes a first lower protective layer, a first recording layer located overlying the lower protective layer, a first upper protective layer located overlying the first recording layer, a first reflective layer located overlying the first upper protective layer, and a heat diffusion layer located overlying the first reflective layer and which mainly contains In, Zn and O.

Abstract: An optical recording medium having two recording layer structures which includes a cover substrate, a grooved substrate, a first recording layer structure, an intermediate layer, a separation layer, and a second recording layer structure. In the optical recording medium, the two recording layer structures include a first recording layer structure, and a second recording layer structure between the substrates, the first recording layer structure includes, in this order, a first protective layer, a first recording layer, a second protective layer, a first inorganic layer, the second recording layer structure includes, in this order, a third protective layer, a second recording layer, a forth protective layer, a second inorganic layer, and a ratio of a thickness of the first recording layer structure and a thickness of the intermediate layer is 0.2 to 1.0.

Abstract: A power determining method is disclosed for determining the light emitting power of a light source upon recording information on an optical disk having plural rewritable recording layers, the method involving obtaining an optimum erasing power with respect to an optimum recording power by recording test data on the optical disk.

Abstract: A method of recording information using a laser on a multilayer optical disk having a plurality of recording layers is provided. The plurality of recording layers include a first recording layer and a second recording layer adjacent the first recording layer. The first recording layer is provided with a first test writing area to be used for calibration of write power, and the second recording layer is provided with a second test writing area to be used for calibration of write power. The disk is arranged so that a first region of the first test writing area is superposed with a second region of the second test writing area when considered in the direction in which the laser is arranged to irradiate.

Abstract: A sputtering target contains a target material including as constituent elements Ag, In, Te and Sb with the respective atomic percents (atom. %) of ?, ?, ? and ? thereof being in the relationship of 0.5??<8, 5???23, 17???38, 32???73, ???, and ?+?+?+?=100, and a method of producing the above sputtering target is provided.

Abstract: A dual-layer structure phase-change type optical recording medium includes a substrate (1), a reflective layer (2), a first protective layer (3), a first recording layer (4), a second protective layer (5), a resin intermediate layer (6), a third protective layer (7), a heat release layer (8) made of Cu or a Cu alloy, a fourth protective layer (9), a second recording layer (10), a fifth protective layer (11) and a cover substrate (12). A product of a reflectance of a high-reflection part and a modulation after recording is a value equal to or higher than a lower limit value for reproduction.

Abstract: To provide a dual-layer recordable optical recording medium, including: a first information layer; intermediate layer disposed over the first information layer; and second information layer disposed over the intermediate layer, the first information layer, intermediate layer, and second information layer being sequentially deposited from a laser irradiation side, wherein the first information layer comprises, from the laser irradiation side, at least a thin film containing Bi as a main ingredient, dielectric layer, reflective layer and thermal diffusion layer, and the second information layer comprises, from the laser irradiation side, at least a thin film containing Bi as a main ingredient, dielectric layer and reflective layer, and wherein the ratio of the thickness of the dielectric layer of the second information layer (t2) to the thickness of the dielectric layer of the first information layer (t1), t2/t1, is in a range of 0.7 to 1.5 or 4.5 to 6.0.

Abstract: An optical recording medium which comprises a substrate and a recording layer disposed on the substrate, in which the recording layer comprises Ga and Sb, a content of the Sb is 80 atm % to 95 atm % relative to a total content of the Ga and the Sb in the recording layer, and recording and erasing are carried out by a reversible phase change between an amorphous phase and a crystalline phase in the recording layer.

Abstract: An optical recording medium configured with a light reflection layer; a first protection layer; a recording layer containing a phase-change material which changes between crystalline and amorphous phases by a light irradiation; a second protection layer; and one of a cover layer and a protective coating layer disposed on a substrate in this order; and in which the light reflection layer is formed of one of an Al alloy and an Ag alloy; the first protection layer has a ZnS—SiO2 mixture layer which contains a mixture of ZnS and SiO2, and a intermediate layer having higher thermal conductivity than the ZnS—SiO2 mixture layer; the intermediate layer is formed on the side of the light reflection layer; the recording layer comprises Ge, Sb, and Te as main elements; and the second protection layer comprises a mixture of ZnS and SiO2.

Abstract: The present invention relates to an recording method for a multi-layered optical recording medium including M phase change recording layers, with M?2. The method comprises recording a mark in a Kth one of said recording layers by using a laser to irradiate the Kth recording layer using a recording pulse train including a plurality of laser beam pulses. The recording pulse train for the Kth recording layer has a cycle of t(K)[T], the 1st recording layer is the recording layer closest the laser beam, and the Mth recording layer is the recording layer furthest from the laser beam, T is a clock cycle. The the following relationship is satisfied: t(1)<t(M), and the cycle of recording pulse train does not decrease from one recording layer to the next recording layer in the direction in which the laser beam irradiates.

Abstract: The present invention provides an optical recording medium comprising a transparent first substrate and a first dielectric layer, a recording layer, a second dielectric layer and a reflective layer which are laminated on the first substrate in this order, wherein the recording layer comprises a thin layer comprising mainly an alloy represented by the composition formula: GexSbyTez (wherein x, y and z represent respectively an atomic %, and x, y and z satisfy respectively the following equations: 3.5?x?10, 70?y?80 and z=100?x?y) and the second dielectric layer comprises a thin film of a compound oxide comprising at least one of a mixture of Nb2O5 and ZrO2, a mixture of Nb2O5 and ZnO and a mixture of Nb2O5, ZrO2 and ZnO.

Abstract: The present invention is aimed at providing a dual-layer phase-change optical recording medium which allows a high-density recording and a recording, where the optical recording medium has a high recording sensitivity even to a low power light with a short wavelength such as blue laser beam, does not cause noises such as jitter, has superior overwrite performance and favorable archivability, allows easier focusing and tracking and enables a compatibility with a ROM. Therefore, it provides an optical recording medium including a substrate and, on the substrate at least a first recording composite layer, an intermediate layer, a second recording composite layer and a cover substrate in this order, wherein the groove depth of the cover substrate is such that the magnitude of a push-pull signal of the first recording composite layer is equal or greater with respect to a push-pull signal of the second recording composite layer.

Abstract: The present invention provides a dual-layer phase-change information recording medium in which the erase ratio in each layer is superior, the dynamic range is improved, and a multi-level recording is possible. For the dual-layer phase-change information recording medium, the compositions of the first recording layer material and the second recording layer material are expressed as Sb?1Te?1Ge?1M1?1 and Sb?2Te?2Ge?2M2?2, respectively, where M1 and M2 are any one element selected from Ag, In, Se, Sn, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Ga, Bi, Si, Dy, Pd, Pt, Au, S, B, C and P; ?1, ?1, ?1, ?1, ?2, ?2, ?2 and ?2 denote percentages by atom and satisfy the following relations: ?1+?1+?1+?1=?2+?2+?2+?2=100; 50??1?75; 25??1?40; 0<?1?10; 0??1?10; 60??2?85; 15??2?30; 0<?2?10; 0??2?10; and ?2+?2<?1+?1??2+?2+20.

Abstract: The purpose of the present invention is to provide a dual-layer phase-change information recording medium which excels in overwrite properties and allows high-density rewriting even when a blue-violet laser is used.

Abstract: The present invention is to provide a practically usable, recordable or rewritable optical information recording medium having a pair of recording layers and a recording and reproducing apparatus for the medium. The recording medium has a pair of recording layer structures on a substrate so as to sandwich a resin intermediate layer, and a recording beam and a reproducing beam are irradiated to two recording layer structures. The pair of recording layer structures respectively have a different track pitch, and the ratio of difference in the track pitch defined by Expression 1 is +0.03 to +0.15, (T2?T1)/T1 ??Expression 1 T1 represents a track pitch of the recording layer structure disposed on the laser beam irradiation side, and T2 represents a track pitch of the recording layer structure disposed on the inner side.

Abstract: The object of the present invention is to enable the identification of double-layer disc type (recordable double-layer disc, rewritable double-layer disc and ROM-type double-layer disc) to be easily and accurately performed. The method for identifying double-layer disc contains obtaining a reflectance of each light by irradiating light of different wavelengths under focused state to each layer of a double-layer disc loaded in an optical apparatus, and identifying if the double-layer disc is a recordable double-layer disc, a rewritable double-layer disc or a ROM-type double-layer disc corresponding to the combination of reflectance of each obtained light. It is preferable that the wavelength of one light is a wavelength for DVD-based disc and the wavelength of the other light is a wavelength for CD-based disc.