Abstract: A protective film for optical disks comprising an acrylic adhesive layer disposed on one face of a light transmitting substrate film, wherein a change in transmittance (X) expressed by equation [1] is 10% or smaller and the amount of elution of halogen ions and the amount of alkaline ions from an acrylic adhesive constituting the acrylic adhesive layer are each 10 ppm or smaller; and an optical disk using the protective film. X(%)=[(Ta−Tb)/Ta]×100  [1] (Ta: an initial transmittance of light of 405 nm through the protective film, Tb: a transmittance of light of 405 nm through the protective film after the protective film is left standing at 80° C. in 85% RH for 1,000 hours). The protective film is used for protecting the information recording layer of the optical disk and the functions of recording and regeneration of the optical disk are not adversely effected.

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: 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: An optical disc is includes a recording layer, a reflective layer, and a protective layer provided, in that order, on one surface of a light-transmissive substrate and a hard coating layer having a thickness in the range of 1 to 5 &mgr;m on the other surface of the substrate. The hard coating layer is formed by applying and curing a solution comprising a hard coating agent containing colloidal silica and a UV-curable acrylic resin and a solvent containing propylene glycol monomethyl ether acetate as a principal constituent. The hard coating layer contains 110 mg/cm3 or less of residual solvent.

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: 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: 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 optical disk for recording or/and reproducing information by using a laser beam includes a substrate formed by an inorganic material having elastic modulus of 2400 MPa or more, or a mixture of inorganic and plastic materials; a reflective layer formed on the substrate; a cover layer formed on the reflective layer; and a protective layer formed on the cover layer, wherein, the laser beam for recording or/and reproducing the information is incident on the protective layer and the cover layer.

Abstract: The present invention provides an optical information recording medium including a substrate with an on-groove and an in-groove, having successively disposed thereon a dye recording layer and a transparent sheet, wherein a width of the on-groove ranges from 50 to 140 nm, and a barrier layer is formed between the recording layer and the transparent sheet. The invention also provides an optical information recording method including irradiating the optical information recording medium with laser light from the side of the medium provided with a cover layer to form a void at a signal pit portion in the dye recording layer and thereby carrying out recording of information as well as an optical information recording medium on which information has been recorded by the method.

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 recording medium includes a substrate, a protective layer and a plurality of information recording layers between the substrate and the protective layer and capable of recording data in the plurality of information recording layers and reproducing data recorded in the plurality of information recording layers by projecting a laser beam via a light incidence plane constituted by one of the surfaces of the substrate and protective layer onto the plurality of information recording layers, each of the information recording layers other than a farthest information recording layer from the light incidence plane including two recording films, a first dielectric film located on the side of the light incidence plane with respect to the two recording films and containing an oxide as a primary component and added with nitrogen, and a second dielectric film located on the opposite side of the light incidence plane with respect to the two recording films and having a lower thermal conductivity than that of the

Abstract: An optical information recording medium of the present invention includes: a substrate with at least one selected from the group consisting of a groove and a pit formed on one surface thereof; at least one information layer provided on the surfaces of the substrate, the information layer including at least one selected from the group consisting of a recording film and a reflective film; a resin layer provided on the information layer; and a light transmission layer provided on the resin layer. The resin layer includes a first resin film and a second resin film disposed in this order from the side of the light transmission layer, and when a water absorption rate of the first resin film is represented by A1 and a water absorption rate of the second resin film is represented by A2, A1 and A2 satisfy: A1>A2. The first resin film and the second resin film may have a different flexural modulus of elasticity.

Abstract: An optical recording medium includes a recording layer and a dielectric layer formed in the vicinity of the recording layer and the dielectric layer contains an oxide as a primary component and being added with nitrogen. The thus constituted optical recording medium can exhibit excellent optical characteristics with respect to a laser beam of desired wavelength used for recording data and reproducing data.

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: 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: A recording medium including a resin substrate having a first thermal expansion coefficient, a center hole, a first surface, and a second surface opposite to the first surface, a recording layer formed on the first surface of the resin substrate and having a recording region, an inner nonrecording region formed inside the inner periphery of the recording region, and an outer nonrecording region formed outside the outer periphery of the recording region, and a protective layer formed on the second surface of the resin substrate except an inner peripheral region having a predetermined range from the center hole, the recording region, and the outer nonrecording region. The thermal deformation suppressing layer has a second thermal expansion coefficient smaller than the first thermal expansion coefficient.

Abstract: An anti-reflection coating layer is formed on the surface portion of a recording medium. This enables to obtain a margin for the air gap thickness change when recording/reproducing an information signal using the “near-field technique” as well as minimize a data loss caused by a collision. Furthermore, the present invention provides a film configuration which can easily be produced.

Abstract: An optical disc for storage and retrieval of digital data, and a system and method for protecting the optical disc is disclosed. The optical disc has projections or embossments on one or both surfaces. When the optical disc is placed on a substantially flat surface such as a tabletop or a desktop, the projections act as pedestals that elevate the optical disc above the flat surface. The resulting gap or clearance helps prevent damage to the optical disc caused by contaminants on the flat surface or by defects in the flat surface. The projections are sized to provide adequate clearance between the disc and the flat surface, while minimizing interference between the projections and components of optical disc readers and drives. The optical disc may also include one or more depressions that are sized and configured to receive projections from another disc, which facilitates stacking of the optical discs.

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: 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 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: An optical recording medium having a scratch-off material layer includes a transparent substrate, a reflective layer formed on the transparent substrate, a protective layer formed on the reflective layer, information formed on a surface of the protective layer, and at least one opaque scratch-off material layer formed on the protective layer for disguising the information.

Abstract: A swing-arm type optical recording and reproducing apparatus and an optical disk applicable to the same. The optical disk includes a substrate having an information recording surface to record and reproduce an information signal, and a protective layer which is provided on the information recording surface and whose surface facing a slider is a flat even surface so that variations in a floating height of the slider can be reduced.

Abstract: An optical recording medium including a substrate having guide groove thereon; a first protective layer located overlying the substrate; a recording layer located overlying the first protective layer; a second protective layer located overlying the recording layer; a third protective layer of from 2 to 9 nm thick located overlying the second protective layer and comprising Si in an amount not less than 35 atomic percent; and a reflection layer including Ag in an amount not less than 95% by weight. An overcoat layer having a glass transition temperature of from 90° C. to 180° C. is preferably formed overlying the reflection layer. A method for manufacturing the optical recording medium is also provided.

Abstract: Novel, quick, and reliable detection methods for determining the authenticity of optical and/or audio disc articles (such as compact discs, digital video discs, CD-ROM discs, and the like) are provided. Such a method basically entails the incorporation of an identifier or marking means within the edges of target optical discs or within any other portion of a target disc such that exposure to non-visible light sources will provide the desired identification upon irradiation or detection of the marking means therein. Such an identifier or marking agent thus may be utilized in conjunction with a transparent holding case whereby the needed light source may be exposed through the transparent walls thereof to permit detection of counterfeit or authentic discs without requiring opening of the case itself. Such a method may also be utilized for discs that are removed from or have not been placed and sealed within such a case as well.

Abstract: The present invention relates to an optical recording medium having a protective layer and a phase-change recording layer on a substrate, said protective layer containing a metallic oxysulfide and an optical recording medium having a protective layer and a phase-change recording layer, said protective layer being formed by sputtering using a target comprising a metallic oxysulfide.

Abstract: This invention provides a method for producing a CD-R optical recording medium. A first stack at a first stage is created by forming on a substrate a recording layer containing an organic dyestuff and a metal layer. At least after a formation of the metal layer; the first stack is transported from the first stage along a transport path towards a second stage through an atmosphere having a relative humidity. The relative humidity is maintained at 40% or less. To control the relative humidity, a shielding plate may be provided around the transport path. An air conditioner may locally control the relative humidity of an area encircled by this shielding plate.

Abstract: A magneto-optical recording medium which is capable of improving the floating stability and the travelling stability of an optical head of a slider type, by forming a lubricating protective layer having a transparent/translucent property on a surface on which the optical head is placed.

Abstract: The present invention is directed to an optical recording medium (1) adapted so that at least a reflection film (3), and a protective film (4) are laminated in succession on a substrate (2), and light is irradiated from the protective film (4) side so that reproduction of information signals is carried out, wherein grooves (5) or emboss pits (6) corresponding to information signals are formed along tracks at the reflection film (3).

Abstract: A write-once high density optical storage medium. The optical storage medium is applicable in an optical read or write system with blue laser having a wavelength in between 385 nm to 425 nm and an objective lens with numerical aperture (NA) greater than 0.8 and includes the following film structure: a substrate; a reflective layer disposed on the substrate; a dye recording layer disposed on the reflective layer; a protective layer disposed on the dye recording layer; and a cover layer disposed on the protective layer. The protective layer prevents direct contact between the dye recording layer and cover layer, thus assuring the medium quality.

Abstract: An optical disc and its manufacturing method in which humps may be prohibited from being formed on an outer rim area of the disc to assure optimum surface properties of a light transmitting layer of the disc to contribute to further increase in recording capacity. On a substrate 2 of an optical disc 1 are sequentially formed a recording portion 6 and a light transmitting layer 5. The light falls on the light transmitting layer 5 to record and/or reproduce information signals for a signal recording area 6a of the substrate 2. The radial distance D from the outermost rim of the substrate 2 to the signal recording area 6a is selected to be larger than the radial width L of a hump 5a formed on the outer rim of the light transmitting layer 5. The hump 5a has a height h from the surface of the light transmitting layer 5 not larger than 70 &mgr;m.

Abstract: There is disclosed an optical recording medium comprising: a transparent resin substrate on which a groove and a land between the grooves disposed adjacent to each other are formed beforehand, wherein recording position information indicating a recording position with respect to an information signal is recorded beforehand on at least one of the groove and land, and a metal reflective film and protective film are successively formed on the groove and land.

Abstract: A phase change recording medium comprising an as-deposited first recording layer configured to undergo a reversible phase change between an amorphous state and a crystalline state due to light irradiation and thereby change an optical characteristic. The as-deposited first recording layer includes a plurality of fine nuclei having an average size of 0.5 nm to 4 nm in the amorphous state.

Abstract: An optical information recording medium including a substrate having successively disposed thereon a recording layer, an interlayer, a pressure sensitive adhesive layer and a cover film in which information is recordable and reproducible by irradiating laser light and the pressure sensitive adhesive layer contains a polymer having a glass transition temperature Tg of 0° C. or lower, as well as a method for producing an optical information recording medium including adhering a cover layer to a surface of a recording layer so that a pressure sensitive adhesive layer is abutted on the surface of the recording layer, and an optical information recording medium produced by the method.

Abstract: A system and method for defining rewriteable data storage media defined by ECMA Standard ECMA-272 2nd edition (1999) for 120 mm DVD rewriteable disk (DVD-RAM) as a write once data storage media and for storing data thereon. The apparatus consists of a data storage device for reading and writing data on the media, the media, a media type indicator in the media, two write protect flags in the user data area of the media, and programming to examine the two write protect flags prior to a write, erase, or format operation. If both flags match and the media type indicator is write once, the drive is prevented from writing to the user data area if both flags are in the data written state. If both flags do not match after two re-reads, an error message is generated. If both flags are in the data unwritten state, data is written to the user data area and both flags are set to the data written state.

Abstract: An optical information recording medium includes a first substrate; a second substrate; and a recording layer formed between the first substrate and the second substrate. The optical information recording medium includes lands and grooves, and a distance between a light source of laser light irradiating the optical information recording medium and the lands is larger than a distance between the light source and the grooves. The lands are formed in the optical information recording medium at a pitch of less than or equal to 0.40 &mgr;m. Each land is either in a first state having a first reflectance or in a second state having a second reflectance lower than the first reflectance, and the first state and the second state are reversibly changeable by the irradiation of the laser light.

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: There is disclosed an optical disk constituted by covering an information recording layer formed on a substrate with a cover layer having a light transmission property, in which ranges of a thickness t and a refractive index n of the cover layer are defined. That is, a function f(n) which is not a constant regarding the refractive index n of the cover layer, and constants t1, t2 determined based on an allowable value of an aberration in the cover layer are used to set the ranges of the thickness t of the cover layer to a range of f(n)−t1≦t≦f(n)+t2.

Abstract: An optical information recording medium of this invention includes a substrate, a light incident surface, a first reflecting layer formed between the substrate and the light incident surface, a second reflecting layer formed between the first reflecting layer and the light incident surface and stacked on the first reflecting layer, the second reflecting layer being made of the same material as that of the first reflecting layer, and a phase change optical recording layer formed between the second reflecting layer and the light incident surface, the phase change optical recording layer transiting between a crystal state and an amorphous state when irradiated with a light beam.

Abstract: Systems and methods are described for inhibiting the readability of an optical media due to changes in a pseudo-reflective material that composes the optical media after the optical media has been exposed to air for a predetermined time. An optical media includes a data encoded component. At least a fraction of the data encoded component transforms from a substantially optically reflective state to a substantially optically non-reflective state as at-least-in-part a function of time from an initializing event. The systems and methods provide advantages because of low cost, limited content lifetime, avoidance of rental returns and minimum changes to existing manufacturing precesses.

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: The present invention provides an optical recording medium and an optical disk device realizing prevention of crosswrite and uniformity of playback signals and capable of easily securing compatibility with a read only disk. It provides an optical recording medium on which light LB condensed by a lens (12, 14) having a numerical aperture of 0.85±0.

Abstract: An electro-optical storage system based on an optical head and a multilayer storage medium in a near-field configuration. The heat generated by absorption of a read/write beam adversely affects the interfacing between the optical head and the medium. The medium has a thermal insulation dielectric layer and/or a heat-dissipating layer to reduce thermal feedback from the medium to the optical head.

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: A phase change optical recording medium is provided wherein the power of the laser beam per unit area required in the initialization is reduced. The optical recording medium has a phase change recording layer satisfying the relations: AI≦8.0%, and CI/AI≧3.0 when the medium is initialized with a light beam having a wavelength &lgr;I, and said recording layer exhibits a reflectivity AI in amorphous region and a reflectivity CI in crystalline region at said wavelength &lgr;I.

Abstract: An optical recording medium protecting film which is a protecting film comprising a single transparent film made of a thermoplastic resin, having a retardation of no greater than 15 nm at a wavelength of 550 nm and a K value of no greater than 40 nm at 550 nm, having a glass transition temperature of 120° C. or higher and a water absorption of no greater than 1 wt %.

Abstract: The present invention provides an optical information recording medium that includes a substrate including a groove with a track pitch of 200 to 400 nm and a groove depth of 20 to 150 nm and having successively disposed thereon a light reflecting layer, a recording layer containing a dye in which information is recorded by irradiation with a laser beam having a wavelength of no greater than 450 nm, an adhesive layer, and a cover layer with a thickness of 0.01 to 0.5 mm. A surface of the optical information recording medium on a side disposed with the cover layer has a center surface average roughness (SRa1) of no greater than 3.0 nm when measured over a large surface area and a center surface average roughness (SRa2) of no greater than 3.0 nm when measured over a minute surface area.