Abstract: An optical information recording medium of the present invention includes a first substrate, a second substrate placed in parallel with the first substrate, and an information layer placed between the first substrate and the second substrate, wherein the information layer includes a recording layer and a dielectric layer (lower dielectric layer/upper dielectric layer) placed so that a distance from the dielectric layer to the recording layer is 20 nm or less. The recording layer is changed between at least two different states that can be identified optically by irradiation of a laser beam incident from the first substrate side, and the dielectric layer contains ZnS and Si as main components.

Abstract: An information recording medium which ensures high reliability and favorable overwrite cyclability is provided, even when an interface layer is not provided between a recording layer and a dielectric layer. The recording layer 4 and the dielectric layers 2 and 6 are formed on the surface of the substrate 1. In the recording layer 4, a phase change is generated between a crystal phase and an amorphous phase by irradiation of light or application of an electric energy. The dielectric layers 2 and 6 are Zr—Zn—S—O-based material layers comprising Zr, Zn, S and O, preferably consisting essentially of a material expressed, for example, with the formula (ZrO2)X(Zn—S)100−X (mol %) wherein X is in the range of 50≦X≦80.

Abstract: 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.

Abstract: Disclosed in this invention is a phase change optical recording material for a rewritable recording medium with a high speed crystallization and excellent erasibility, which comprises a composition having the formula of: (AaBbCc)x(GeaSbbTec)1−x wherein, A is an element selected from the elements belonging to the IVB group in the periodic table; B is an element selected from the elements belonging to the VB group in the periodic table; C is an element selected from the elements belonging to the VIB group in the periodic table; a, b and c are atomic ratios; x is a mole fraction in the range of 0 to 1; and at least one of A, B and C has a higher atomic number and thus a smaller diatomic bond strength than that of the corresponding element in the GeSbTe part.

Abstract: An optical information recording medium, especially a CD-RW medium, that can undergo direct overwriting at high speed is disclosed. The optical information recording medium includes a transparent substrate, at least a recording layer and a reflective layer on or above the substrate and is capable of performing at least one of recording, erasing and rewriting information by irradiating and scanning with focused light to thereby form and/or erase recording marks on the recording layer.

Abstract: The inventions relates to a laser beam optical recording medium which features several read/write levels, comprising a first half-transparent level and at least a second level, the first one being close to the laser transmitting source, each level comprising a phase changing material layer with two stable states controlled by a laser beam, where the phase changing material is a metallic alloy whose chemical formula writes as: [(GeyTe1-y)a(SbzTe1-z)1-a]1-b(In1-xTex)b with: 0.4≦y≦0.6 0.3≦z≦0.5 0.4≦x≦0.6 0.3≦a≦0.5 0.01≦b≦0.3 the reflection coefficient of the first level being in the range from 10% to 30%, the transmission coefficient being at least 45%, the writing power being lower than 23 mW and the erasing power being lower than 10 mW.

Abstract: An phase-change optical disk comprises a substrate, a first protective layer, a first thermostable layer, a recording layer, a second thermostable layer, a second protective layer, an absorptance control layer, and a heat-diffusing layer which are provided in this order from a side on which a laser beam comes thereinto, wherein a recording layer material has composition ratios which are within a range surrounded by composition points of B3 (Bi3, Ge46, Te51), C3 (Bi4, Ge46, Te50), D3 (Bi5, Ge46, Te49), D5 (Bi10, Ge42, Te48), C5 (Bi10, Ge41, Te49), and B5 (Bi7, Ge41, Te52) on a triangular composition diagram. Recrystallization is not caused even when information is recorded on an inner circumferential portion, a reproduced signal is scarcely deteriorated even when rewriting is performed multiple times, and any erasing residue of amorphous matters scarcely appears at an outer circumferential portion.

Abstract: An information recording medium includes a first information layer and a second information layer. The first information layer includes a first recording layer in which a reversible phase change is caused between a crystalline phase and an amorphous phase by irradiation of a laser beam or application of current. The second information layer includes a second recording layer in which a reversible phase change is caused between a crystalline phase and an amorphous phase by the irradiation of the laser beam or the application of the current. The first recording layer is made of a first material, the second recording layer is made of a second material, and the first material is different from the second material.

Abstract: Provided is a medium having a phase change recording layer wherein crystallization of the recording layer is facilitated, and at the same time, wherein the region to be crystallized is crystallized at an accurate dimension. The optical recording medium has a recording layer 4 comprising at least one phase change layer 41 and at least one functional layer 42 in contact with said phase change layer. The phase change layer 41 in its as-deposited state is amorphous, and crystals having Fm3m structure or R3m structure are produced upon crystallization of this layer. The functional layer 42 in its as-deposited state is crystalline, and contains crystals having Fm3m structure. The material used for the functional layer 42 is the one which exhibits a thermal conductivity of 0.03 to 5 W/cmK as measured in thin film form of 100 nm thick.

Abstract: An ultra-high density data storage and retrieval unit has a phase-change layer for storing and retrieving data and at least one other layer. The phase-change layer and/or the other layer comprises a two-dimensional material, primarily one of the chalcogen-based materials.

Abstract: To provide an information recording medium which permits high density recording/reproduction, which has good thermal stability, and which, due to the use of an interface layer with a high sputter rate, has good recording/reproduction characteristics and is excellent for mass production. An information recording medium wherein the thickness of an interface layer 3 is 0.25 or more but 0.67 or less of the total thickness of a first protective layer 2 and the interface layer 3, and the interface layer 3 contains at least tantalum (Ta) and oxygen (O). The medium is excellent for mass production and has good recording/reproduction characteristics for high density recording/reproduction.

Abstract: The subject matter of the invention is to provide an optical recording medium with improvements in repeated overwrite characteristics, write power margin, archival stability and the like. The invention provides an optical recording medium having a semi-transparent layer mainly comprising Ag, a first protective layer comprising a dielectric, a phase-change recording layer comprising an alloy mainly comprising SbxTe1−x (0.7<x≦0.9), a second protective layer comprising a dielectric, and a metallic reflective layer in this order, wherein the medium further has an interdiffusion-protection layer between the semi-transparent layer and the first protective layer where the first protective layer comprises a sulfur-containing dielectric, and the medium has a higher reflectance to light incident on the semi-transparent layer side with the recording layer being in an amorphous state than in a crystalline state.

Abstract: The present invention relates to a rewritable multi-layer recording medium that ensure appropriate data reading from and writing in an arbitrary recording layer of a plurality of recording layers. The recording layers are stacked via spacer layers. Each recording layer is made from a material of which reflectance changes upon radiation of a light beam. Information or data is written in the recording layer as a result of reflectance change. Each recording layer has at least one groove and/or at least one pit. A certain layer in which the information is to be written (recorded) has a rewritable region. An adjacent layer has a window region through which the light beam passes and reaches the rewritable region. The window region imparts a diffraction effect, which is different from a diffraction effect impartable from a region surrounding the window region, to the passing light beam.

Abstract: An optical recording medium 10 comprises a substrate 1, first protective layer 2, interfacial layer 3, recording layer 4, second protective layer 5, light absorbing and heat generating layer 6, third protective layer 7, reflection layer 8 and a protective film 9 laminated in order. The light absorbing and heat generating layer 6 is a metal layer or an alloy layer containing more than one element out of Ge, Sn, Pb, Cr, Ti, In, Si, Cd, Se, W, Mo, Zr, Nb, Zn and Hf, so that a reflectivity of the optical recording medium 10 and an optical modulation factor, which is an optical modulation factor in a phase changing state of crystalline or amorphous, in the recording layer 4 can be always maintained in high. Accordingly, a recording sensitivity of the recording layer 4 in the optical recording medium 10 can be increased without deteriorating a characteristic such as reflectivity and jitter.

Abstract: An optical information recording composition suitable for use as a recording layer of an optical information recording medium. The optical information recording composition contains Sb, and one or two elements selected from N and O, and optionally one or more elements M selected from Ge, Te, Bi, Sn, Ag, Au, In, Pb, Pd, Pt, Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ta, Ga, Zr, Nb, Mo, Ru, Rh, Hf, W, Re, Os, Ir, Dy and Th. A light beam having a wavelength of 200-800 nm can be used to record information on the optical information recording medium and retrieve information therefrom.

Abstract: An optical recording medium wherein a recording layer, an absorbent layer and a radiating layer are provided in this order as seen from a recording/reproducing light incidence side and recording/reproduction is carried out on a condition that an extinction coefficient k of the absorbent layer is k>0 in a wavelength of recording/reproducing light, and a relationship between a wavelength &lgr; of the recording/reproducing light and a numerical aperture NA of an irradiating optical system of the recording/reproducing light is &lgr;/NA≦680 nm. An optical recording medium wherein an absorbent layer and a recording layer are provided in this order as seen from a recording/reproducing light incidence side and an extinction coefficient k of the absorbent layer is k>0 in a wavelength of recording/reproducing light, and a signal including a minimum mark having a mark length Ms of MS≦0.17 &mgr;m is recorded.

Abstract: A multi-time rewritable information recording medium conducting writing by the change of arrangement of atoms under the irradiation of light, comprising, from the light-incident side, a substrate of a thickness of 0.7 mm or less, a lower protective layer of a thickness of 20 nm to 60 nm, a recording film, an upper protective layer, and a reflective layer, wherein the interval between tracks is 0.62 &mgr;m or less. The medium can also possess favorable writing/reading characteristics at high density writing/reading, have large processing margin, use a manufacturing apparatus at a reduced cost, cut material cost, and realize mass productivity with less stresses.

Abstract: An optical information recording medium which can eliminate the necessity for the initialization process. A crystallization assisting layer (3) comprising a given material is formed over a substrate (1) on one side thereof, and a recording layer (4) comprising a Ge—Sb—Te alloy is formed directly on the layer (3). Since the recording layer (4) crystallizes immediately after film formation, no initialization process is necessary for the optical information recording medium obtained. Examples of the material of the crystallization assisting layer firstly include materials having a face-centered cubic lattice system crystal structure. Examples thereof secondly include tellurium-free materials having a rhombohedral lattice system crystal structure. An especially preferred crystallization assisting layer is a discontinuous island-like film made of a material comprising bismuth and/or a bismuth compound.

Abstract: An optical recording medium is provided which comprises: a substrate including concentrically or spirally formed grooves each having a V-shaped cross section; a first dielectric layer formed on the substrate; a phase-change recording layer formed on the first dielectric layer; a second dielectric layer formed on the phase-change recording layer; and a metallic reflecting layer formed on the second dielectric layer. In particular, the optical recording medium is so formed that an objective lens having an aperture number of 0.55-0.70 can be used and a laser beam having a wavelength of 600-700 nm and passing through the objective lens is passed through the substrate and then converged on the recording layer, thereby recording or reproducing information on the recording layer in areas corresponding to the grooves.

Abstract: A phase change optical recording medium having a wide recording power margin and excellent durability to repetitive recording is disclosed. The medium includes a first protective layer, a recording layer, an interface layer, a second protective layer, and a reflective layer, the layers disposed on a transparent substrate, wherein the interface layer includes a mixture of ZrO2. Preferably, the medium further includes a second interface layer including the mixture of ZrO2 between the first protective layer and the recording layer.

Abstract: An information recording medium includes a first information layer and a second information layer. The first information layer includes a first recording layer in which a reversible phase change is caused between a crystalline phase and an amorphous phase by irradiation of a laser beam or application of current. The second information layer includes a second recording layer in which a reversible phase change is caused between a crystalline phase and an amorphous phase by the irradiation of the laser beam or the application of the current. The first recording layer is made of a first material, the second recording layer is made of a second material, and the first material is different from the second material.

Abstract: An optical recording medium. The optical recording medium has a substrate and a stack of layers provided thereon. The stack of layers includes a phase change recording layer, having a melting point Tmp, sandwiched between a first and a second dielectric layer. The stack of layers further includes a crystallization-accelerating layer in contact with the recording layer, a reflective layer, and an optional cover layer. The crystallization-accelerating layer may of a binary metal alloy or a semiconductor and has a melting point Tmg at least 250° C. higher than the melting point Tmp of the recording layer and may have a crystal structure similar to the crystalline state of the recording layer.

Abstract: An optical information recording medium comprises a substrate and a multilayered film formed on the substrate, the multilayered film comprising a first information layer, a separating layer, and a second information layer in this order from the side of the substrate. Each of the first information layer and the second information layer comprises a recording layer in which an optical change is caused by irradiation of laser light, and in the first and second information layers, signals can be recorded/reproduced on/from the recording layer by irradiating the recording layer with laser light through the substrate. The first information layer comprises a first protective layer, the recording layer, and a second protective layer in this order from the side of the substrate, and at least one of the first protective layer and the second protective layer comprises at least two layers. The at least two layers comprise a first layer and a second layer in this order from the side near the recording layer.

Abstract: An optical information recording medium that is a phase-change type optical disk includes, on a transparent substrate having a land and a groove, a phase-change type recording layer in which an optically detectable reversible change occurs between an amorphous phase and a crystalline phase by irradiation with an energy beam, wherein dielectric layers are provided so as to be in contact with at least one side of the phase-change type recording layer, the phase-change type recording layer contains at least one selected from the group consisting of Te, Se, Sb, In, Ge, and Ag as a main component, aid the dielectric layers contain, as main components thereof, at least one selected from the group consisting of Ge and Si, and N.

Abstract: A write once medium having a phase change recording layer is provided. In this medium, stable recorded state and high crystallizability of the recording layer are simultaneously realized. The optical recording medium has a recording layer 4 comprising at least one phase change layer 41 and at least one functional layer 42 in contact with the phase change layer. The component constituting the phase change layer 41 and the component constituting the functional layer 42 undergoes a reaction to produce a reaction product when the phase change layer 41 is heated to a temperature equal to or higher than the melting point of the phase change layer 41, and the area where the reaction product has formed experiences decrease in its optical reflectivity, and the optical reflectivity after such decrease is maintained even if the area wherein the reaction product has formed is heated to the crystallization temperature of the phase change layer.

Abstract: A phase-change optical information recording medium in which information can be recorded, erased, and read includes a substrate and a recording layer overlying the substrate. The recording layer achieves a crystal phase and an amorphous phase. The absorptance Ac of the recording layer in the crystal phase against light having a wavelength of from 370 nm to 450 nm is lower than the absorptance Aa of the recording layer in the amorphous phase against the light. Information is recorded on the recording medium with a recording wavelength of from 370 nm to 450 nm at a recording pitch of 0.3 &mgr;m to 0.52 &mgr;m.

Abstract: A phase-change optical disk includes a first dielectric layer, reflecting layer, first interface layer, recording layer, second interface layer, second dielectric layer, and light-transmitting layer sequentially formed on a support substrate. Information is written on, read from, and erased from the phase-change optical disk by changing a crystalline state of the recording layer with a laser beam radiated from a light-transmitting layer side. A disk reflectance Rc obtained when the recording layer is in a crystalline state is not less than 3% and not more than 12%. A difference in absolute value between the disk reflectance Rc and a disk reflectance Ra which is obtained when the recording layer is in an amorphous state is not less than 10%. A refractive index of one of the first and second interface layers for the laser beam with a wavelength &lgr; is higher than 2.

Abstract: A method for fabricating read-only copy protected optical medium comprising a light-sensitive material at positions capable of altering the data read during copying of the optical medium but permitting read of the underlying data in the reading of the optical medium.

Abstract: An optical disk exhibits enhanced overwrite overwrite characteristics and cross-erase suppression. An optical disk includes a flattening layer formed on a substrate; a reflective layer formed on the flattening layer; a phase-change optical recording layer formed on the reflective layer, the recording layer being changeable between crystalline and amorphous states, portions of the recording layer to become the crystalline state exhibiting reflectivity lower than other portions of the recording layer to become the amorphous state; a plurality of dielectric layers stacked on the recording layer, at least two of the dielectric layers having different optical constants; and a light absorbing layer formed at one location selected from a location between the recording layer and the lowermost layer of the dielectric layers, a location between any of two adjacent layers of the dielectric layers, and a location on the uppermost layer of the dielectric layers.

Abstract: An optical information recording medium comprises a transparent substrate on which an information layer is disposed, the information layer comprising a recording layer and a dielectric layer, and the recording layer containing Te, O and M (wherein M is one or more elements selected from Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Sb, Hf, Ta, W, Re, Os, Ir, Pt, Au and Bi), wherein a content ratio of O-atom in the recording layer ranges from 25 atomic percent to 60 atomic percent, and a content ratio of M-atom therein ranges from 1 atomic percent to 35 atomic percent, and a refractive index n of the dielectric layer is not less than 1.5.

Abstract: A rewritable or write-once medium with increased recording density and sensitivity is disclosed, the medium having at least a first dielectric layer, a recording layer and a second dielectric layer in this order on a substrate, wherein at least one of the first and second dielectric layers is formed by applying a colloidal dispersion which comprises inorganic dielectric nanoparticles having an average particle size of 1 to 50 nm and having the surface thereof modified with an adsorptive compound, and the recording layer is formed by applying a colloidal dispersion which comprises metal chalcogenide nanoparticles having an average particle size of 1 to 20 nm and having the surface thereof modified with an adsorptive compound. The dielectric layer and the recording layer are formed by spin coating or web coating.

Abstract: An optical information recording medium having a recording layer for inducing a reversible phase change by irradiation with energy beam. The recording layer contains Te, Ge, Sb, and N, and the concentration of the N being contained is in a range of about 0.1% by atom to about 10% by atom. In this constitution, an excellent repeated recording and erasing performance is obtained.

Abstract: An optical information recording medium which can eliminate the necessity for the initialization process. A crystallization assisted layer (3) comprising a given material is formed over a substrate (1) on one side thereof, and a recording layer (4) comprising a Ge—Sb—Te alloy is formed directly on the layer (3). Since the recording layer (4) crystallizes immediately after film formation, no initialization process is necessary for the optical information recording medium obtained. Examples of the material of the crystallization assisted layer firstly include materials having a face-centered cubic lattice system crystal structure. Examples thereof secondly include tellurium-free materials having a rhombohedral lattice system crystal structure. An especially preferred crystallization assisted layer is a discontinuous island-like film made of a material comprising bismuth and/or a bismuth compound.

Abstract: In an optical recording medium comprising a phase change recording layer (4) containing Sb and optionally, Te and/or In as a main component, the recording layer is able to be crystallized to provide a crystallized region which contains rhombohedral crystals consisting essentially of Sb and is substantially free of a crystal phase other than the rhombohedral crystals. When the recording layer contains a rare earth element, Zr, Hf, Ti or Sn as an auxiliary component, the medium has a dielectric layer (31) composed of silicon oxide, silicon nitride, aluminum oxide, or a mixture of zinc sulfide and at least 30 mol % of silicon oxide, disposed contiguous to and in front of the recording layer (4) as viewed from the recording/reading beam incident side. The medium has a high transfer rate and improved thermal stability.

Abstract: A WORM optical recording element comprising a substrate and a phase-change recording layer wherein the phase-change recording layer has a composition expressed by SbaXbSncZndSieOfSh wherein X is an element selected from In, Ge, Al, Zn, Mn, Cd, Ga, Ti, Si, Te, Nb, Fe, Co, W, Mo, S, Ni, O, Se, Tl, As, P, Au, Pd, Pt, Hf,or V and a>0, b>0, c>0, d>0, e>0, f>0, h>0, and a +b+c+d+e+f+h=100.

Abstract: An optical data recording medium includes a light transmittable plastic substrate, and a recording layer formed on the plastic substrate and containing an inorganic compound body and metal particles dispersed in the inorganic compound body. The inorganic compound body is made from a material selected from a group consisting of a metal oxide and a metal nitride.

Abstract: An optical disc having excellent recording/retrieving characteristics and capable of improving the surface properties of the reflective layer without reducing the thermal conductivity, the reflectivity and producibility. An optical recording medium for recording and/or retrieving information by irradiation of light, which comprises a substrate, and an interlayer, a reflective layer containing a metal as the main component and a recording layer, formed in this order on the substrate directly or via another layer made of a resin or a dielectric material, wherein as observed from a light-incoming direction, the reflective layer is located in front of the interlayer, the interlayer contains the same metal as the metal constituting the main component of the reflective layer and also contains oxygen and/or nitrogen, and the interlayer has a content of the metal smaller than the reflective layer.

Abstract: A multi-layered optical disc having its recording unit comprised of plural information recording layers, in which two or more information recording layers are layered on a substrate 0.3 to 1.2 mm in thickness, with the interposition of a transparent layer, to form a recording unit, a light transmitting protective layer is formed on the recording unit to a thickness of 10 to 177 &mgr;m and in which the light is illuminated from the side of the light transmitting protective layer to effect recording and/or reproduction of information signals. At least one of the information recording layers except the information recording layer formed at a remotest position from the light transmitting protective layer has a phase change material as a recording material.

Abstract: An optical recording medium is provided with a recording layer made of a phase-change recording material including Ag, In, Sb, and Te as the main constituent elements, with the respective atomic percents of a, b, c, and d thereof being in the relationship of 0.1≦a≦5, 5≦b≦13, 62≦c≦73, 22≦d≦26, and a+b+c+d≧97. Alternatively, the recording material includes the constituent elements of Ag, In, Sb, Te, and Ge, with the respective atomic percents of a, b, c, d, and e thereof being in the relationship of 0.1≦a≦5, 5≦b≦13, 62≦c≦73, 22≦d≦26, 0.3≦e≦3, and a +b+c+d+e≧97. A sputtering target for forming the recording layer is also disclosed.

Abstract: An information recording medium has a substrate and a recording layer on the substrate, the recording layer is partially transformable between a crystalline state and an amorphous state by being partially heated and cooled so that a signal is recorded in the recording layer by the partial transformation, and the recording layer includes oxygen.

Abstract: In an information recording medium comprising at least a substrate, a recording layer, and a resin layer, the substrate is formed with at least a pit corresponding to a read only area 31 and a groove corresponding to a recording/reproducing area 32 without overlapping with each other. A reflectivity of the recording layer is specified to be more than 10%. The recording layer and the resin layer are continuously adhered over both the read only and recording/reproducing areas 31 and 32. The information recording medium is characterized in that both push-pull signal outputs T1 and T2, which are reproduced from the read only area 31 and the recording/reproducing area 32 respectively, are more than 0.1 and satisfy an inequality 1.5≧T1/T2≧0.5.

Abstract: A method of forming a crystalline, phase-change layer that remains atomically smooth on its surface. Also, an atomically smooth, crystalline, phase-change layer made according to this method. The method can include forming a phase-change layer over a substrate, forming a thick capping layer over the phase-change layer, changing the phase-change layer from an amorphous phase to a crystalline phase, removing the thick capping layer, and forming a thin capping layer over the phase-change layer.

Abstract: This invention relates to a rewritable optical information recording medium essentially comprising a substrate and a recording layer formed on said substrate, wherein the recording layer has the following composition:

Abstract: In a material for a heat-resistant protection layer and constituting one of the components of a phase variation type recording medium , at least one compound having a thermal conductivity of higher than 10 W/m·deg inclusive in a bulk state is contained. This kind of material realizes a phase variation type optical data recording medium having a high erasure ratio and allowing data to be repeatedly recorded and erased a number of times by small power even at the time of high-speed recording and erasure.

Abstract: An optical recording medium is disclosed which incorporates a recording layer made of a phase-change material. The optical recording medium has a structure such that the ratio Ac/Aa of absorptance Ac realized when the recording layer is in a crystal state and absorptance Aa realized when the recording layer is in an amorphous state is 0.9 or higher. Moreover, a crystallization enhancing layer for enhancing crystallization of the phase-change material is formed which is made to contact with at least either surface of the recording layer. Since control of the absorptance and enhancement of crystallization are simultaneously performed, the difference between the physical properties of crystal and those of amorphous can be reliably compensated for. Thus, a satisfactory direct overwriting can be performed even under high speed and dense conditions.

Abstract: In order to ensure CAV recording/reproduction while preventing jitter deterioration and modulation decrease and thereby ensuring sufficient recording properties, even at a linear velocity higher than 4.8 m/s, a first dielectric film, phase change versatile recording film, second dielectric film, reflection film and protective film are formed on a disc substrate having formed lands and grooves on one major surface. The recording film is made of a GeInSbTe alloy, and the reflection film is made of an AgPdCu alloy or AlCu alloy. Composition of the GeInSbTe alloy is adjusted to contain Ge in the range of 1 to 6 wt %, In in the range of 2 to 6 wt %, and control Sb/Te in the range of 2.2 to 3.0. Composition of the AgPdCu alloy is adjusted to contain Cu not more than 1.5 wt %. Regarding groove conditions, groove depth is controlled in the range of 40 to 50 nm, groove width in the range of 0.40 to 0.

Abstract: In order to increase the recording capacity while preventing jitter deterioration and a decrease of the modulation factor and thereby ensuring satisfactory recording characteristics, a first dielectric film, phase recording film, second dielectric film, reflection film and protective film are sequentially formed on a disc substrate having formed lands, grooves and wobbling on one major surface. The recording film is made of a GeInSbTe alloy, and the reflection film is made of an AgPdCu alloy or AlCu alloy. Composition of the GeInSbTe alloy is adjusted to contain Ge in the range of 1 to 8 wt %, In in the range of 2 to 6 wt %, and control Sb/Te in the range of 2.2 to 3.0. Composition of the AgPdCu alloy is adjusted to contain Pd in the range of 0.9 to 1.5 wt % and Cu not more than 1.5 wt %. Composition of the AlCu alloy is adjusted to contain Cu in the not more than 1.5 wt %. Groove depth is controlled in the range of 35 to 45 nm, groove width in the range of 0.35 to 0.

Abstract: In order to ensure CAV recording/reproduction while preventing jitter increase and modulation decrease and thereby ensuring sufficient recording properties, even at a linear velocity in the range of 3.49 to 8.44 m/s, a first dielectric film, phase-versatile recording film, second dielectric film, reflection film and protective film are formed on a disc substrate having formed lands, grooves and wobbling on one major surface. The recording film is made of a GeInSbTe alloy, and the reflection film is made of an AgPdCu alloy or AlCu alloy. Composition of the GeInSbTe alloy is adjusted to contain Ge in the range of 1 to 6 wt %, In in the range of 2 to 6 wt %, and control Sb/Te in the range of 2.4 to 3.0. Composition of the AgPdCu alloy is adjusted to contain Cu not more than 1.5 wt %. Groove depth is controlled in the range of 30 to 40 nm, groove width in the range of 0.27 to 0.

Abstract: A description is given of a rewritable optical data storage medium having a phase-change recording layer on the basis of an alloy of Ga-In-Sb, which composition is situated within the pentagonal area TUVW in a triangular ternary composition diagram. These alloys show an amorphous phase stability of 10 year or more at 30° C. Such a medium is suitable for high speed recording, e.g. at least 30 Mbits/sec, such as DVD+RW, DVD−RW, DVD-RAM, high speed CD-RW, DVR-red and DVR-blue.

Abstract: The optical information medium for rewritable recording by means of a laser-light beam (14, 15) has a first recording stack (8) having a phase change type recording layer (10), sandwiched between two dielectric layers (9, 11), and has a second recording stack having a phase change type recording layer (5), sandwiched between two dielectric layers (3, 5). A transparent spacer layer (7) is interposed between the first recording stack (8) and the second recording stack (2). A metal mirror layer (3) is present proximate the second recording stack (2) at a side remote from the transparent spacer layer (7). The first recording stack (8) has a phase change type recording layer (10) with substantially growth dominated or substantially nucleation dominated crystallization. The second recording stack (2) has a phase change type recording layer (5) of a kind different from the kind selected for the first recording stack (8).