Abstract: The present invention provides an optical information medium having excellent weather resistance and repeating characteristics. The optical information medium has a barrier layer between a protective layer and a recording layer. The barrier layer includes GeN or GeON, and at least one element selected from the group consisting of Al, B, Ba, Bi, C, Ca, Ce, Cr, Dy, Eu, Ga, H, In, K, La, Mn, N, Nb, Ni, Pb, Pd, S, Si, Sb, Sn, Ta, Te, Ti, V, W, Yb, Zn and Zr.

Abstract: An optical information recording medium having a multilayer structure comprising at least a lower protective layer, a phase-change type optical recording layer, an upper protective layer and a reflective layer, on a substrate, wherein the phase-change type optical recording layer has a composition of Zn&ggr;1In&dgr;1Sb&zgr;1Te&ohgr;1, where 0.01≦&ggr;1≦0.1, 0.03≦&dgr;1≦0.08, 0.5≦&zgr;1≦0.7, 0.25≦&ohgr;1≦0.4, and &ggr;1+&dgr;1+&zgr;1+&ohgr;1=1, whereby overwrite recording is carried out by modulation of light intensity of at least strong and weak two levels, so that a crystalline state is an unrecorded state, and an amorphous state is a recorded state.

Abstract: An optical information recording medium including a first and second information layers is provided with an area where only the first information layer, which is provided nearer a substrate, exists, and initialization using a laser beam is started from this area. In an area where the second information layer exists, the first information layer is initialized after the second information layer is initialized. Alternatively, the first and second information layers are initialized at the same time by a flash light with adjusted emission time, emission energy, and the like. The first information layer is initialized after the second information layer is initialized by radiating a plurality of flash lights.

Abstract: In an optical disk for high density recording, for preventing the deformation of recording tracks caused by stress which may develop between the substrate and the recording stacked film formed thereon, a stress-compensation layer having a metal element such as Ti or Cr as a main component is provided. The stress-compensation layer undergoes contraction (tensile stress) to compensate for compression stress which develops in the stacked film during cooling after the thermal expansion of the substrate surface that occurs at the end of film formation. The stress-compensation layer has a pillar-like structure which, starting from the lower face, reaches the upper face of the film.

Abstract: An optical recording medium includes a recording layer, a first dielectric layer disposed on the side of a light incidence plane through which the laser beam enters with respect to the recording layer, a second dielectric layer disposed on the side opposite to the light incidence plane with respect to the recording layer, a heat radiation layer disposed on the side of the light incidence plane with respect to the first dielectric layer and a reflective layer disposed on the side opposite to the light incidence plane with respect to the second dielectric layer, the recording layer containing a phase change material represented by an atomic composition formula: SbaTebGecMnd, where a is equal to or larger than 57 and equal to or smaller than 74, c is equal to or larger than 2 and equal to or smaller than 10, d is equal to or larger than 5 and equal to or smaller than 20, (a+d) is equal to or larger than 74 and equal to or smaller than 81 and a/b is equal to or larger than 2.9 and equal to or smaller than 4.

Abstract: A phase-change optical information recording medium capable of recording information therein, reproducing recorded information therefrom, rewriting recorded information, and erasing recorded information therefrom, which phase-change optical information recording medium is provided with a recording layer containing therein a phase-change recording material including Ge, Ga, Sb, Te, and one element selected from the group consisting of Mg and Ca, which recording material is capable of performing a reversible phase transition from a noncrystalline phase to a crystalline phase and vice verse with the application of an electromagnetic wave thereto.

Abstract: A rewritable recording medium having a synchronizing signal portion recorded with a synchronizing signal information and a data portion recorded with data information after the synchronizing signal portion. Each time the synchronizing signal information is rerecorded, a length of the synchronizing signal portion changes and a start position of the synchronizing signal portion changes.

Abstract: Fabrication of an MO disc, the formation of a master pattern of servo and track information, and the subsequent transfer of that pattern to a series of pits and grooves on a substrate. On top of that substrate, at least one sacrificial layer is provided atop a relatively hard layer. The recording stack may be provided with both silicon nitride and silicon dioxide top layers, with the silicon dioxide layer acting as a sacrificial layer to ensure that the hard layer, of silicon nitride, remains at the end of the process. A layer of aluminum or aluminum alloy may be deposited, with the aluminum plugs filling the grooves and pits (created by the embossed servo information) to a level higher than any of the adjacent layers of silicon dioxide, silicon nitride, or similar dielectric layer.

Abstract: Optical information-recording media comprise a first transparent substrate through which a laser beam enters, a first information-recording layer deposited on the first transparent substrate, a first reflection film formed on the first information-recording layer, an intermediate layer deposited on the first reflection film, a second information-recording layer formed on the intermediate layer, a second reflection film deposited on the second information-recording layer, and a second substrate provided on the second reflection film. The recording film of each of the first and second information-recording layers has a main composition represented by (GeTe)xSb2−yInyTe3, and its composition ratio is within ranges of 0.04≦y<2 and 4≦x≦8.

Abstract: An optical disk has a substrate, a first protective layer formed on the substrate, a recording layer formed on the first protective layer, a second protective layer formed on the recording layer, and a reflective layer formed on the second protective layer. The recording layer includes a composition expressed as (SbxTe1-x)aGebInc in which atomic ratios are 0.77≦x≦0.84, 0.85≦a≦0.95, 0.01≦b≦0.10 and 0.01≦c≦0.10 where a+b+c=1.

Abstract: An optical information-recording medium 1 is constituted by depositing a quarter-wave plate 4, a hologram-recording layer 3 and a reflection layer 5 on a transparent base plate 2 in this order. Reproducing reference light (P-polarized light) passes through the quarter-wave plate 4 to change into a circularly polarized light, and then the circularly polarized light enters the hologram-recording layer 3, so that the reproducing light (circular polarization) generated from the hologram-recording layer 3 passes through the quarter-wave plate 4 to change into a S-polarized light. On the other hand, stray light SL1 (P-polarized light) resulting from the process in which the reproducing light is reflected from the surface of the base plate or in the inside thereof has an vibration direction different from that in the stray light SL2 (P-polarized light) resulting from the process in which the reproducing reference light goes and returns in the inside of the optical information-recording medium 1.

Abstract: A novel optical recording material is provided, which is capable of recording and reading an information signal by utilizing a change in the double refraction caused by a change in the molecular orientation of a side-chain type polymer liquid crystal which has an electrocyclic-reaction-type photochromic compound (or a residue thereof).

Abstract: An initialization method in which a phase change optical recording medium is initialized with a laser beam having a power density of from 15 to 22 mW/&mgr;M2 at a linear velocity of from 8 to 12 m/s. The phase change optical recording medium is formed of a transparent substrate having a guide groove on the surface thereof, a first protective layer, a recording layer, a second protective layer and a reflective layer. The recording layer material may be represented by the following composition formula: Ag&agr;X&bgr;Sb&dgr;Te&egr;Ge&ggr;, wherein X is at least one of Ga, In, Tl, Pb, Sn, Bi, Cd, Hg, Mn, Dy, Cu and Au, and &agr;, &bgr;, &dgr;, &egr;, and &ggr; have units of atomic % and satisfy particular relationships.

Abstract: In a data storage subsystem, drive-level processing treats data storage media as WORM by automatically advancing a write append limiter as data is written, and preventing changes to data occurring before the write append limiter. Despite this media's WORM nature, the drive-level processing permits limited overwriting of data at the end of tape since the write append limiter lags the current write location by the margin of a write allowance index. Thus, despite the drive's treatment of the media as WORM, the drive permits overwriting of trailing metadata in order to facilitate write append operations.

Abstract: A description is given of a phase-change optical data storage medium (20 having a recording stack (2) with a recording layer (6) and a metal reflective layer (3) comprising at least one transparent layer (4, 8) of the material indium tin oxide (ITO). Use of an ITO layer (4, 8) in the recording stack (2) improves the cooling behavior of the recording layer (6) combined with good optical contrast. Thus, higher possible data rates are achieved.

Abstract: An initialization method of an optical recording medium having a plurality of optical recording layers capable of reducing uneven initialization due to light interference caused at the time of initialization without deterioration of information recording/reproducing signal characteristics of the recording layers is provided.

Abstract: The optical data storage medium (20) has a substrate (1) with a surface area having tracks (4) of marks representing stored information. The information is readable by means of a scanning radiation beam (10). A reflective layer (2) is present, reflecting the radiation beam (10). The medium has a radiation beam (10) reflection larger than 50%. The reflective layer (2) comprises a compound of the formula Al100-y,Xy, in which formula Al is aluminum and X is an element selected from the group of Ge and Si. The letter y is the atomic fraction of X in at. %. The value of y is in the range 5<y<35. The reflective layer (2) has a radiation beam absorption, which enables controlled ablative recording or solid-phase change recording of an identification mark (6, 6′).

Abstract: There is provided a phase-change type optical recording medium, including: a substrate; a recording layer formed on the substrate, phase condition of the recording layer being changed when a laser beam is radiated thereonto, to thereby record, erase or reproduce data into or from the recording layer; and a reflection layer formed on the recording layer for reflecting a laser beam having been radiated onto the recording layer. The recording layer is formed so that the following equation is established: Rc>Rm>Ra wherein Rc indicates a reflectivity to be obtained when the recording layer is in crystal condition, Ra indicates a reflectivity to be obtained when the recording layer is in amorphous condition, and Rm indicates a reflectivity to be obtained when the recording layer is in mixed condition of molten condition and crystal or amorphous condition.

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 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: 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: An information recording medium of the present invention includes a first substrate, a second substrate disposed so as to be opposed to the first substrate, a first information layer disposed between the first substrate and the second substrate, a second information layer disposed between the first information layer and the second substrate, and an intermediate layer disposed between the first information layer and the second information layer. The first information layer includes a first recording layer that is transformed in phase reversibly between a crystal phase and an amorphous phase with a laser beam, and the second information layer includes a second recording layer that is transformed in phase reversibly between a crystal phase and an amorphous phase. The first recording layer contains, Ge, Sn, Sb, and Te, and has a thickness of 9 nm or less.

Abstract: A high density optical disc that can be driven changeably with the existent optical disc by the same driving apparatus. On the recording surface of the optical disc, a light transmissive layer with a thickness of about 0.2 to 0.4 mm is formed. The recording face is accessed by allowing a light beam with a wavelength of 395 to 425 nm in a spot shape to be irradiated onto it. Also, the light beam is converged in a spot shape by an objective lens having the numerical aperture of about 0.62 to 0.68.

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 optical disk is manufactured by bonding a resin stamper having, on a principal plane, asperity pits on which a thin film is formed and a second substrate having a thickness of 0.3 mm or less with radiation cured resin such that the asperity pits face to the second substrate. The resin stamper is peeled off after curing the radiation cured resin to form asperity pits on the second substrate. A metal film is formed on the asperity pits on the second substrate to attain an information recording layer on the second substrate. A first substrate having an information recording layer and the second substrate having the formed information recording layer are bonded such that the both information recording layers face each other.

Abstract: Tracking control is carried out by a push-pull method or by mechanical feed at the time of recording signals, and tracking control is carried out by a phase difference tracking method at the time of reproduction. Thus, a phase change type optical disk which enables phase difference reproduction and is erasable may be realized. In a phase change type optical disk having a phase difference reproduction structure, servo mechanism at the time of reproducing signals may be stably controlled by causing the reflectance of a blank portion to be higher than the reflectance of a recording mark portion.

Abstract: A magnetic head device comprising a head section 55 for applying a magnetic field to a disk. The head section 55 includes a magnetic field generating section 61 and a slider 62. The slider 62 supports the magnetic field generating section 61 and may be set in sliding contact with the disk. The magnetic field generating section 61 has a magnetic core 63 and a coil 64 wound around the magnetic core 63. The section 61 is designed to generate the magnetic field and embedded in and formed integral with the slider 62. The head section 55 excels in heat-radiating property.

Abstract: A product for recording information by use of laser light includes a recording layer being able to change between an amorphous state and a crystalline state so as to record information, the recording layer having a thickness falling within a first range defined relative to a wavelength of the laser light, a protection layer having a thickness falling within a second range defined relative to the wavelength of the laser light, a heat releasing layer having a thickness falling within a third range defined relative to the wavelength of the laser light, and a transparent substrate supporting the layers. The first, second, and third ranges are selected such that a phase of the laser light reflected by the amorphous state and a phase of the laser light reflected by the crystalline state have a phase difference larger than a predetermined phase amount.

Abstract: The present invention provides an optical recording medium in which two or more information-recording layers are laminated for obtaining a high recording density, and also incidence of light and detection of return light can be performed with high efficiency relating to an information-recording layer at a position distant from a light-incident side, thus having satisfactory recording and reproduction characteristics; and also provides an optical recording and reproducing method for performing at least recording or reproduction of information using this optical recording medium.

Abstract: An information recording medium capable of high-density recording and accurate reproduction and also capable of repeated recording and reproduction, an information recording device that employs the information recording medium has a Co—Si oxide thin film 1 constructed such that columnar crystals 2 are separated by an intergranular phase 3 which contains SiO2 having a lower coefficient of thermal conductivity than the columnar crystals 2. Therefore, the intergranular phase 3 prevents heat transfer from one columnar crystal 2 to another. In addition, the intergranular phase 3 separates columnar crystals 2 from each other, so that the crystalline structure of each columnar crystal 2 is not affected by its adjacent columnar crystal 2.

Abstract: A description is given of a disc-shaped rewritable optical information medium having an IPIM stack (2) comprising a phase-change recording layer (4) sandwiched between two dielectric layers (3,5), and a metal mirror layer (6). The thickness of the recording layer (4) increases gradually with increasing radius r. As a result, the complete erasure time CET of recorded marks decreases from the inner radius ri to the outer radius ro. Therefore, at a point closer to the outer radius marks can be recorded at a higher linear speed than at a point closer to the inner radius. This effect ensures that the recording medium can be used for recording at a constant angular velocity (CAV).

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: A phase change optical recording medium according to an embodiment of this invention includes a substrate, a reflecting layer which reflects a light beam, a phase change recording layer which is arranged between the substrate and the reflecting layer and changes between a crystalline state and an amorphous state when irradiated with the light beam, a first dielectric layer which is arranged between the substrate and the reflecting layer, and a second dielectric layer which is arranged between the substrate and the first dielectric layer and has a thermal conductivity lower than that of the first dielectric layer.

Abstract: Structures of storage media for optical storage systems, especially for systems in the near-field configuration to couple radiation between the optical head and the media at least in part by evanescent fields.

Abstract: 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.

Abstract: Disclosed is an optical recording medium, comprising a polymer alloy forming a phase-separated domain structure of a coating object, and a volatile substance interacting with the polymer alloy. The volatile substance in a vapor state is deposited on the surface of specific phase-separated domain, and dispersedly infiltrated into the phase-separated domain. The phase-separated domain and the volatile substance chemically interact with each other. The optical recording medium is operable to perform optical recording by utilizing change in the transmittance, reflectance, refractive index or surface potential thereof in response to irradiation of ultraviolet light, visible light, or infrared light from outside. The present invention can provide an optical recording medium suitable for high-density recording in a wide wavelength range.

Abstract: It is an object of the present invention to provide an optical recording medium having a new information recording part and an entertainment system employing it. According to an optical recording medium of the present invention, a new information recording part (210) is formed on parts other than the information recordable part (200O, 200D, 200I), and information can be written, read, and erased.

Abstract: This invention provides an optical disk effective in both precision and productivity, and to a process for the manufacture thereof. The optical disk allows reading of the information recorded on each information-recording surface of the two or more information-recording surfaces by varying the focal position of a playback laser beam incident on and passing through said light transmitting substrate; and the optical disk is provided with a transparent layer that is laminated onto the light transmitting substrate and is constituted of a thermoplastic resin sheet of uniform thickness and the transparent layer has an information-recording surface other than the surface of said light transmitting substrate formed thereon.

Abstract: A high-density information recording medium free from lowering the reflectance by over-write of a large number of times and exfoliation defect in a structure for suppressing cross-erase. This medium includes, over a substrate having a groove shape, a recording layer, and three-layered thin films of a first interference layer, a second interference layer and an interface layer having mutually different compositions and disposed on a laser beam incidence side of the recording layer in order named from the laser beam incidence side. The first interference layer has a smaller refractive index and a larger thermal conductivity than the second interference layer, the interface layer is interposed between the second interference layer and the recording layer, and a distance between the first interference layer and the recording layer is greater than at least a groove depth.

Abstract: An optical recording apparatus comprises a means for calculating an optimum recording power, capable of varying a recording power to perform a recording process on a test recording area of the erasable optical disc, and calculating an optimum recording power according to signals obtained by reproducing the test recording area; and an a means for calculating an optimum erasing power from the optimum recording power and a coefficient corresponding to the optimum recording power. The optimum recording power and the optimum erasing power are used for recording the erasable optical disc. Thereby, even though the dispersion of the recording power becomes large, the erasing power is not greater than a certain range; therefore, the total of the recording power and the erasing power can be restrained and the degradation of the durability, that the optical disc can be repeatedly recorded, can be suppressed.

Abstract: In an optical information medium comprising a supporting substrate, an information recording layer thereon, and a light-transmitting layer wherein a recording/reading laser beam enters the recording layer through the light-transmitting layer, the light-transmitting layer is formed of a resin and has a tensile strength at break of 5-40 MPa, a tensile elongation at break of 15-100%, and a tensile modulus of 40-1,000 MPa. The medium has improved recording/reading characteristics when a laser beam defines a beam spot having a small diameter of up to 300 &mgr;m and the medium is rotated at a high linear velocity of at least 8 m/s.

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 data storage medium includes a first substrate, the first substrate including a plurality of first data structures; a second substrate positioned above the first substrate, the second substrate including a plurality of second data structures; a reflective layer positioned on the second substrate to cover the second data structures; and a masking layer interposed between the reflective layer and the first substrate to cover the first data structures, the masking layer having a varying reflectivity to thereby render the second data structures unreadable.

Abstract: The present invention relates to a recording method for a recording medium having multi-recording layers. When an information signal is recorded on the recording medium which has layers including a light transmission protective layer (6), a first recording layer (5) on which laser beam incident from the light transmission protective layer (6) side is scanned along first guide grooves (51), and a second recording layer (3) on which laser beam incident from the light transmission protective layer (6) is scanned along second guide grooves (21), the information signal is recorded on either the guide grooves or areas between the guide grooves of the recording layer of the first recording layer (5) and the second recording layer (3) located near the light transmission protective layer (6).

Abstract: A recordable optical disc (100) is provided with a disc substrate (110); a record track (102) formed on the disc substrate spirally or coaxially around a center of the disc substrate; and an emboss pit formed in a predetermined zone on the disc substrate in correlation with predetermined data, which is recorded on the record track in the predetermined zone.

Abstract: An optical recording medium for at least one of recording and reproduction of information by focusing of light from an optical system on a recording layer, comprising a substrate, a recording layer formed on the substrate, a first protective layer formed on the recording layer, and an antireflection multilayer film, designed to be positioned at a near field distance from the optical system, formed on the first protective layer for preventing reflection of the light at the surface of the first protective layer and having predetermined optical characteristics for moderating a change of a reproduced signal intensity along with fluctuation of a distance between the antireflection multilayer film and the optical system, a method of producing the medium, and an optical recording and reproduction device including the medium.

Abstract: Noise of the read-out signal is reduced in an optical information medium comprising a supporting substrate and a reflective layer disposed on the supporting substrate wherein the reading beam irradiates the medium from the side where the reflective layer is formed. In addition, noise of the read-out signal is reduced without adversely affecting the recording properties in an optical information medium comprising a supporting substrate, and a reflective layer and a recording layer disposed on the supporting substrate in this order wherein the recording beam irradiates the medium from the side where the reflective layer is formed. In the medium, the reflective layer has a crystallite size of up to 30 nm.

Abstract: An optical recording medium and a method for fabricating the same. A read only data region, a writable/readable data region and a content recording region are formed on a transparent substrate. The read only data region is used to store prerecording data which can only be read but is unable to be rewritten. The writable/readable data region is used to read and write data, while the content recording region is used to record initial address information of the recorded data in the read only data region, the writable/readable data region and the content recording region. A recording layer in the writable/readable data region is formed with the derivative of cyanine dye, phthalocyanine dye or azo dye. Or alternatively, the recording layer is made of an alloy containing tellurium, germanium, or antimony, or an alloy containing indium, silver, antimony or tellurium.

Abstract: An optical recording medium includes a recording layer and a mask layer on a substrate. The mask layer is formed of a material whose light transmittance is decreased by light irradiation and is increased by heating.

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.