Abstract: In an information recording medium, a Bi—Ge—Te material is adopted as a phase-change recording layer material. A C—Ta—O material is used for at least any one of first and second boundary layers which are in contact with a recording layer.

Abstract: An optical recording medium includes a substrate 11 with a concave and convex shape for dividing a track area formed on its surface, an optical recording layer 12 having a compound consisting of at least tin (Sn), nitrogen (N) and oxygen (O) formed on the surface in which the concave and convex shape is formed and a light transmission layer 13 formed on this optical recording layer 12. Then, a compound composition SnxNyOz of tin (Sn) nitrogen (N) and oxygen (O) comprising the optical recording layer 12 is selected so as to satisfy 30<x<70 (atomic %), 1<y<20 (atomic %) and 20<z<60 (atomic %). According to this arrangement, the optical recording medium can improve jitter caused when Sn is used as a recording material.

Abstract: A super resolution information storage medium includes: a substrate; a first super resolution layer which is formed over the substrate; a second super resolution layer which is formed over the first super resolution layer; and an insertion layer which is disposed between the first and second super resolution layers.

Abstract: To provide an optical recording medium and the like that is adapted to higher density and higher speed recording of 8 times or more than that of DVD (about 28 m/sec or more) and that exhibits superior repeating and reservation properties. An optical recording medium is provided that comprises a substrate, and a recording layer, wherein at least one of recording, reproducing, erasing, and rewriting of information is carried out by means of reversible phase changes at marks on the recording layer, the reversible phase changes at marks are induced between crystalline and amorphous states by laser irradiation, the length of the respective marks is 0.4 ?m or less in the traveling direction of the laser irradiation, and the recording layer has a composition expressed by the formula: In?Sb?, wherein ? and ? are atomic percent of the respective elements; 0.73??/(?+?)?0.

Abstract: A silver-based alloy thin film is provided for the highly reflective or the semi-reflective layer of optical discs. Alloy additions to silver include magnesium, gold, rhodium, ruthenium, osmium, platinum, palladium, copper, silicon, cadmium, tin, lithium, nickel, cobalt, manganese, indium, chromium, antimony, gallium, boron, molybdenum, zirconium, beryllium, titanium, aluminum, germanium and zinc. These alloys have moderate to high reflectivity and reasonable corrosion resistance in ambient environments.

Abstract: A silver-based alloy thin film is provided for the highly reflective or semi-reflective coating layer of optical discs. Elements that can be added to silver to produce useful silver alloys include zinc, aluminum, copper, manganese, germanium, yttrium, bismuth, scandium, and cobalt. These alloys have moderate to high reflectivity and reasonable corrosion resistance in the ambient environment.

Abstract: This invention discloses a novel rewritable phase-change recording medium for optical data storage, which is based on the GaSbTe ternary alloy system. The designed compositions reside on the Sb7Te3—GaSb and Sb2Te3—GaSb pseudo-binary tielines, and the claimed region can be expressed by the formula (SbxTe100-x)1-z(GaySb100-y)z, 35?x?80, 40?y?50, 0.05?z?0.9. The crystallized phase of the GaSbTe films is a single phase after laser annealing, and the crystal structure is hexagonal with continuous variation in lattice constants. The lattice parameters, a is from 4.255 ? to 4.313 ? and c is from 11.200 ? to 11.657 ?, corresponding to the c/a ratio 2.60 to 2.73. The crystallization kinetics shows increased crystallization temperature (181 to 327° C.) and activation energy (2.8 to 6.5 eV) with increasing GaSb content.

Abstract: Disclosed is an optical data storage medium with enhanced contrast. The optical data storage medium includes a substrate having oppositely facing first and second surfaces. A first metal/alloy layer is formed overlaying the first surface of the substrate. The first metal/alloy layer is formed from tin, antimony and element selected from the group consisting of indium, germanium, aluminum, and zinc. After the first metal/alloy layer is formed, a first dielectric layer is formed overlaying the first metal/alloy layer. This dielectric layer is formed from silicon oxynitride. The first metal/alloy layer is positioned between the substrate and the first dielectric layer.

Abstract: A multi-stack optical data storage medium for rewritable recording by a focused laser-light beam, the medium having a substrate with deposited on aside thereof: a first recording stack comprising a phase-change type recording layer at least one further recording stack comprising a phase-change type recording layer, a transparent spacer layer adjacent each further recording stack. The further recording stack is sufficiently transmissive to ensure proper sensitivity for reading and recording in the first recording stack. For this purpose, at least one indium tin oxide layer is present in at least one of the further recording stacks. The indium tin oxide layer further ensures proper cooling behavior of the recording layer of the further recording stack in order to obtain sufficient recording performance in the farther recording stack.

Abstract: A multilayer optical information recording medium includes optical information recording layers, and dielectric multilayer reflecting layers provided under the optical information recording layers respectively. Each of the dielectric multilayer reflecting layers includes: a laminate of low refractive index films and high refractive index films; and a variable refractive index film exhibiting change of refractive index induced by laser beam irradiation. Each of the dielectric multilayer reflecting layers is provided so that reflectance of a portion used for reading/writing information by condensed laser beam irradiation is high while transmittance of the other portion is high. It is possible to reduce intensity of laser beam to be irradiated to the medium.

Abstract: A phase-change optical recording medium has a first information layer including a phase-change optical recording film arranged in a position close to the light incident side, a second information layer including another phase-change optical recording film arranged in a position remote from the light incident side and an interlayer separating film arranged between the first information layer and the second information layer, in which at least one of the first information layer and the second information layer includes a noise reduction film in contact with the interlayer separating film. The noise reduction film is formed of SiOx (1?x?2) or SiOC.

Abstract: An optical information recording medium including a substrate, a light absorbing layer which is located overlying the substrate and in which marks are formed to store information and a light reflection layer located overlying the light absorbing layer including a crystal, wherein the optical information recording medium satisfies the relationship, Lt/4 ?Lc? Lm, wherein Lc represents the average particle diameter of the crystal of the light reflection layer, Lm represents the minimum length of the marks, and Lt represents the thickness of the light reflection layer.

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. The recording layer contains an alloy and/or an intermetallic compound mainly containing Ga, Ge, Sb, and Te in a compositional ratio represented by the following formula: GaxGey(SbzTe1-z)1-x-y wherein x, y, and z each represent an atomic ratio of a positive real number less than 1 and satisfy the following conditions: 0.02?x?0.06, 0.01?y?0.06, 0.80?z?0.86, x?y, and x+y?0.1.

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 has a plurality of laminated information recording layers. The average reflectivity within a stipulated range in the unrecorded regions of at least one of the information recording layers has a value between the reflectivity in the crystalline state and the reflectivity in the amorphous state. When the focus of the laser beam is aligned to one information recording layer, the difference in reflectivity is small between the case in which those regions of the other information recording layer on which the beam spot shines is a recorded region and the case in which it is an unrecorded region, and even in the case that a boundary between a recorded region and an unrecorded region is present within the beam spot, the distribution of reflectivity within the beam spot becomes constant, so the stable recording and/or playback can be performed.

Abstract: A method of fabricating a nano/micro structure comprising the following steps is provided. First, a film is provided and then a mixed material comprising a plurality of particles and a filler among the particles is formed on the film. Next, the particles are removed by the etching process, the solvent extraction process or the like, such that a plurality of concaves is formed on the surface of the filler, which serves as a nano/micro structure of the film.

Abstract: A silver-based alloy thin film is provided for the highly reflective or semi-reflective coating layer of optical discs. Elements that can be added to silver to produce useful silver alloys include zinc, aluminum, copper, manganese, germanium, yttrium, bismuth, scandium, and cobalt. These alloys have moderate to high reflectivity and reasonable corrosion resistance in the ambient environment.

Abstract: A silver-based alloy thin film is provided for the highly reflective or the semi-reflective layer of optical discs. Alloy additions to silver include magnesium, gold, rhodium, ruthenium, osmium, platinum, palladium, copper, silicon, cadmium, tin, lithium, nickel, cobalt, manganese, indium, chromium, antimony, gallium, boron, molybdenum, zirconium, beryllium, titanium, aluminum, germanium and zinc. These alloys have moderate to high reflectivity and reasonable corrosion resistance in ambient environments.

Abstract: A silver-based alloy thin film is provided for the highly reflective or the semi-reflective layer of optical discs. Alloy additions to silver include gold, rhodium, ruthenium, osmium, platinum, palladium, copper, silicon, cadmium, tin, lithium, nickel, cobalt, manganese, indium, chromium, antimony, gallium, boron, molybdenum, zirconium, beryllium, titanium, aluminum, germanium and zinc. These alloys have moderate to high reflectivity and reasonable corrosion resistance in ambient environments.

Abstract: A phase-change optical recording medium has a phase-change recording film to which recording and erasure can be reversibly performed by irradiation with light, and at least one dielectric film formed of a SiOC film containing Si, O and C, and having a carbon concentration within a range of between 0.1 and 30 atomic %.

Abstract: A phase-change optical recording medium has a phase-change recording film to which recording and erasure can be reversibly performed by irradiation with light, and at least one dielectric film formed of a SiOC film containing Si, O and C, and having a carbon concentration within a range of between 0.1 and 30 atomic %.

Abstract: A silver-based alloy thin film is provided for the highly reflective or semi-reflective layer of optical discs. Alloy additions to silver include gold, rhodium, ruthenium, osmium, platinum, palladium, copper, silicon, cadmium, tin, lithium, nickel, cobalt, indium, chromium, antimony, gallium, boron, molybdenum, zirconium, beryllium, titanium, magnesium, and zinc. These alloys have moderate to high reflective and reasonable corrosion resistance in the ambient environment.

Abstract: Provided is a sputtering target and an optical recording medium having formed thereon a phase change optical disc protective film having zinc sulfide as its principal component employing such a target, as well as the manufacturing method thereof, characterized in that the sputtering target has zinc sulfide as its principal component, and is capable of adjusting the refractive index of a film containing conductive oxide in the range of 2.0 to 2.6. This sputtering target, and an optical recording medium having formed thereon a phase change optical disc protective film having zinc sulfide as its principal component employing such a target, is capable of reducing particles (dust emission) and nodules that arise during sputtering, has minimal variation in quality and is capable of improving mass productiveness, and in which the crystal grain is fine and has a high density of 90% or more.

Abstract: In an information recording medium of the present invention, a recording layer and first and second dielectric layers are formed on a surface of a substrate. In the recording layer, at least one of recording and reproduction is caused by irradiation of light or application of electric energy. The dielectric layers are oxide-based material layers or oxide-nitride-based material layers containing an oxide of at least one element selected from the group GM consisting of Sn, Ga and Zn, and at least one of an oxide and a nitride of at least one element selected from the group GL consisting of Al, Si and B, or oxide-fluoride-based material layers containing a fluoride of at least one element selected from La and Ce, and one example of at least one of element selected from the group GM.

Abstract: An optical information recording medium includes a recording layer for recording optical information, a plurality of laminated layers, and a substrate for supporting those layers, while a beam of a specific wavelength is being radiated, a light absorption peak is shifted to a longer or a shorter wavelength side than the peak located before said beam radiation, realizing a high S/N ratio and a high recording density of the medium.

Abstract: Disclosed is a super resolution optical disc. The super resolution optical disc comprises at least two mask layers. In one embodiment, the super resolution optical mask comprises a plurality of mask layers and impact absorption layers between the mask layers, and may further comprise diffusing prevention layers between the mask layer and the impact absorption layer. In another embodiment, the super resolution optical mask comprises a plurality of recording layers and dielectric layers separating the recording layers, each of the recording layers including two mask layers and an impact absorption layer between the mask layers or including two mask layers, an impact absorption layer between the mask layers, and diffusion preventing layers between the mask layer and the impact absorption layer. Accordingly, recording marks have an enhanced shape at an outer periphery of the marks, thereby enhancing the quality of the reproduction signal and enabling high-density multi-level recording.

Abstract: A phase-change optical recording medium has a recording film that brings about reversible phase-change between a crystalline phase and an amorphous phase upon irradiation with light and an interface film formed in contact with at least one surface of the recording film and comprising hafnium (Hf), silicon (Si), oxygen (O) and carbon (C).

Abstract: An optical information medium (20) for recording, such as DVR-blue, and a method for manufacturing such a medium (20) is provided. Reading from and recording onto the medium (20) is performed by means of a focused radiation beam (10) having a radiation wavelength ? and a numerical aperture NA. Said medium has a substrate (1), and a stack (2) of layers provided thereon. The stack (2) comprises at least a first recording stack (3) and k radiation beam transmissive layers (4, 5). Each transmissive layer (4, 5) has a refractive index ni and an average thickness di ?m and 1?i?k and k?2. The thickness dk of layer k (5) is determined by a simple formula which depends on the parameters ni for i=1 . . . k and di for i=1 . . . k?1. Such a medium (20) has zero or substantially zero spherical aberration at the focal point, being at the recording layer of the first recording stack (3), of said radiation beam (10).

Abstract: A disk with an Ag reflective layer, a recording layer including elements Sb and Te, and a dielectric layer including S provided between the reflective layer and the recording layer has the problems of corrosion of the Ag reflective layer, decline of the signal quality due to insufficient heat releasing ability, and exfoliation between the layers. (1) A phase-change optical disk includes, on a transparent substrate, a recording layer in which an optically detectable reversible change between an amorphous phase and a crystalline phase can be caused by irradiation with an energy beam, a reflective layer, and a dielectric layer arranged between the recording layer and the reflective layer, wherein the main component of the dielectric layer is an oxide or a nitrooxide of Ta.

Abstract: An optical information recording medium on which information can be recorded and reproduced by using a laser beam is provided. The medium includes a substrate with a guide groove and a multilayered metal film including at least a first metal layer, a barrier layer and a second metal layer that are deposited on the substrate in this order, or a single layer metal film including at least a metal layer and a recording layer are deposited on the substrate in this order. The second metal layer and the metal layer of the single layer metal film are a material containing Al and a metal element (an additive) as main components.

Abstract: A method of increasing the efficiency of a multiphoton absorption process and apparatus. The method includes: providing a photoreactive composition; providing a source of sufficient light for simultaneous absorption of at least two photons; exposing the photoreactive composition to at least one transit of light from the light source; and directing at least a portion of the first transit of the light back into the photoreactive composition using at least one optical element, wherein a plurality of photons not absorbed in at least one transit are used to expose the photoreactive composition in a subsequent transit.

Abstract: A phase-change recording material used for an information recording medium utilizing a crystalline state as a non-recorded state and an amorphous state as a recorded state, which has the composition of the following formula (1) as the main component: (Sb1?xSnx)1?y?w?zGeyTewM1z??formula (1) wherein each of x, y, z and w represents atomicity, x, z and w are numbers which satisfy 0.01?x?0.5, 0?z?0.3 and 0?w?0.1, respectively, and the element M1 is at least one element selected from the group consisting of In, Ga, Pt, Pd, Ag, rare earth elements, Se, N, O, C, Zn, Si, Al, Bi, Ta, W, Nb and V, and (I) when z=0 and w=0, y is a number which satisfies 0.1?y?0.3, (II) when 0<z?0.3 and w=0, y is a number which satisfies 0.05?y?0.3, and (III) when 0?z?0.3 and 0<w?0.1, y is a number which satisfies 0.01?y?0.3.

Abstract: A phase-change optical recording medium has a phase-change recording film to which recording and erasure can be reversibly performed by irradiation with light, and at least one dielectric film formed of a SiOC film containing Si, O and C, and having a carbon concentration within a range of between 0.1 and 30 atomic %.

Abstract: The invention provides an optical recording disk, with which the worsening of jitter can be prevented effectively even when fingerprints become adhered onto a laser light incidence surface. An optical recording disk 10 comprises a substrate 2, a recording layer 5, formed on the substrate, a light transmitting layer 7, formed on the recording layer, and a hard coat layer 8, formed on the light transmitting layer, and is characterized in that, when an operation of adhering an artificial fingerprint solution onto the optical recording disk's light incidence surface, onto which laser light is made incident, is performed and then an operation of wiping off the artificial fingerprint solution that has been adhered onto the light incidence surface is repeated five times, jitter becomes no more than 1.15 times that prior to the adhesion of the artificial fingerprint solution.

Abstract: A phase-change recording material on which high velocity recording/erasing is possible, which provides excellent recording signal characteristics, which provides a high storage stability of the recording signals, with which the change in the reflectivity of the recorded signals is small even after a long term storage, and which provides excellent recording signal characteristics even if overwriting is carried out again, and an information recording medium employing the above material, are provided. It is characterized by containing as the main component a composition represented by Gex(InwSn1-w)yTezSb1-x-y-z (wherein the Sb content is higher than any one of the Ge content, the In content, the Sn content and the Te content, and x, y, z and w representing atomicity ratios satisfy (i) 0?x?0.3, (ii) 0.07?y-z, (iii) wxy-z?0.1, (iv) 0<z, (v) (1?w)xy?0.35 and (vi) 0.35?1-x-y-z).

Abstract: The present invention provides a hard coat agent composition that is useful for forming a hard coat layer with excellent anti-staining properties and lubricity, as well as superior scratch resistance and abrasion resistance, on the surfaces of various articles. The present invention also provides an optical information medium using the above hard coat agent composition. A hard coat agent composition comprising a fluorine-containing block copolymer (A1), a fluorine-containing polyether compound (A2) comprising an active energy ray-reactive group, and an active energy ray-curable compound (B). An optical information medium comprising a film element composed of one or more layers including at least a recording layer (4) or a reflective layer, on a supporting substrate (20), wherein at least one of the supporting substrate (20)-side surface and the film element-side surface is formed of a hard coat layer (8) comprising a cured product of the hard coat agent composition.

Abstract: An optical disk from which recorded data are read out by means of light irradiation has a substrate having recording pits as data on a surface thereof, and stacked films formed on the substrate. The stacked films contain a super-resolution film of a polymer matrix and semiconductor particles having an organic group covalently bonded thereto, and a reflective film reflecting light. The super-resolution film and the reflective film are provided in this order from a light incident side.

Abstract: A phase-change recording material on which high speed recording/erasing is possible, which has excellent recording characteristics, which has a high storage stability of recording signals and which is excellent in the repeated recording durability, and an information recording medium using the above material are provided. A phase-change recording material characterized by containing as the main component a composition represented by {(Sb1?xGex)1?yIny}1?z?wMzTew wherein x, y, z and w are numbers satisfying 0.001?x?0.3, 0?y?0.4, 0?z?0.2 and 0?w?0.1, and M is at least one element selected from lanthanoids, provided that z and w are not 0 at the same time.

Abstract: The present invention provides a hard coat agent composition that is useful for forming a hard coat layer with excellent anti-staining properties and lubricity, as well as superior scratch resistance and abrasion resistance, on the surfaces of various articles. The present invention also provides an optical information medium using the above hard coat agent composition. A hard coat agent composition comprising a fluorine-containing polyether compound (A) comprising an active energy ray-reactive group, and a curable compound (B) comprising two, or three or more active energy ray-polymerizable groups within each molecule. An optical information medium comprising a film element composed of one or more layers including at least a recording layer (4) or a reflective layer, on a supporting substrate (20), wherein at least one of the supporting substrate (20)-side surface and the film element-side surface is formed of a hard coat layer (8) comprising a cured product of the hard coat agent composition.

Abstract: An optical information recording medium of the present invention includes a transparent substrate and a multi-layered film provided on the transparent substrate. The multi-layered film includes at least a recording layer that is changed between two or more different states capable of being detected by irradiation with a light beam, and a light absorbing layer in this order from a side close to the transparent substrate. The recording layer contains a material represented by a formula: Gex(BiySb1?y)2Tex+3 (where x?5 and 0<y?1) as a main component. Such a multi-layered film including a recording layer also is applicable to a multi-layered recording medium including a first information layer to an N-th information layer (N is an integer of 2 or more) disposed on a transparent substrate in this order from a side close to the transparent substrate. In this case, at least one of the first information layer to the N-th information layer has the same configuration as that of the multi-layered film.

Abstract: A write once recording medium comprising an inorganic material serving as a recording layer is disclosed. The inorganic material has a formula, A(1?y)My, wherein A is comprised of Si or Sn; M is comprised of Al, Ag, Au, Zn, Ti, Ni, Cu, Co, Ta, Fe, W, Cr, V, Ga, Pb, Mo, In or Te; and y is in the range of 0.02˜0.8.

Abstract: An optical disc having a transition linear velocity of 8-11 m/s when irradiating continuous light with 11±1 mW and a wavelength of 660±10 nm using a pickup head with a numerical aperture (NA) of 0.65, and satisfying the following condition: ?R=|Rb—Ra|?3% where Rb is a reflectance of an unrecorded area, and Ra is a reflectance of the top of an eye pattern after ten cycles of recording. In one recording mode therefor, the disc is rotated at a constant angular velocity so as to have a linear velocity of 3–4 m/s on an innermost track and a linear velocity of 8–9 m/s on an outermost track. In another mode, the disc is rotated at a constant angular velocity so as to have a linear velocity of 5–6 m/s on an innermost track and a linear velocity of 13–14 m/s on an outermost track.

Abstract: A multilayer information recording medium has both good reproducing performance and good recording and rewriting capabilities, as well as good repeated rewriting capabilities even after being archived for a long period of time. The information recording medium has at least a first recording layer and a second recording layer, which generate reversible phase changes between the crystalline phase and the amorphous phase. The first recording layer contains Ge, Te and Bi, while the second recording layer contains Sb and one or more elements M1 selected from a group including V, Mn, Ga, Ge, Se, Ag, In, Sn, Te, Pb, Bi and Au.

Abstract: When a wavelength of a first laser beam with which a first recording medium including a first recording layer is recorded and reproduced is indicated as ?1 (nm), a wavelength of a second laser beam with which a second recording medium including a second recording layer is recorded and reproduced as ?2 (nm), the relationship between the wavelength ?1 and the wavelength ?2 is set to be expressed by 10?|?1??2|?120. The first recording layer has a light absorptance ratio of at least 1.0 with respect to the wavelength ?1. The light transmittance of the first recording medium with respect to the wavelength ?2 is set to be at least 30 in both the cases where the recording layer is in a crystal state and in an amorphous state. In order to record and reproduce the optical multilayer disk with the above-mentioned characteristics, a multiwavelength light source with the following configuration is used.

Abstract: A phase-change optical recording medium capable of performing recording and reproduction at a high speed is provided, in which a reproduced signal output is not only sufficiently large but the phase-change optical recording medium also has excellent repeated rewriting performance. An interface layer 3, which is composed of a Ge—Si—N-based material, is formed on at least a surface of one side of a recording layer 4 of the phase-change optical recording medium 10. Accordingly, even when a phase-change material having a high melting point, for example, a Bi—Ge—Te-based phase-change material is used for the recording layer 4, it is possible to provide the phase-change optical recording medium in which the reproduced signal output is sufficiently large and the repeated rewriting performance is excellent.

Abstract: A media storage device and method for fabricating said device is provided. The device comprises a data layer capable of storing and erasing data via application of an energy beam, such as a near field optical non diffraction limited beam or electron beam. A separate capping layer is deposited on the data layer. The separate capping layer is relatively transparent to the energy beam and may be formed from various materials, including but not limited to an epitaxial material, a conducting material, and a robust high melting point material, such as Molybdenum.

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 ?m to 0.52 ?m.

Abstract: Problem to be solved is that when an information recording medium is repeatedly subjected to recording of information several hundreds times, the atoms in a protective layer are diffused and dissolved into a recording layer to lower a reflectivity greatly and make the medium unendurable to many times of overwriting. This problem can be solved by a medium constituted of interference layer 10, interface layer 12, phase-change type recording layer 14, protective layer 13 having a tin content of from 23.3 atomic % to 32.3 atomic %, and a heat sink layer 8 successively formed on substrate 1, as seen from a light-incidence side. By use of this medium, the dissolution of atoms can be prevented, and overwriting for many times can be achieved.

Abstract: A write-once optical information recording medium is provided that is capable of realizing a high transfer rate and a method of recording and reproducing information on and from the optical information recording medium. The optical information recording medium is constructed by stacking a reflective layer 12, a first dielectric layer 13, a recording layer 14, a write-protect layer 15, a second dielectric layer 16 and a transparent cover layer 17 on a polycarbonate substrate 11. The recording layer 14 is made of a phase-change material, and the cover layer 17 is made of UV curing resin. The recording layer 14 is irradiated with a laser beam with a wavelength of 500 nm or less to change from a crystalline phase to an amorphous phase. The write-protect layer 15 prevents the recording layer 14 from changing back to the crystalline phase from the amorphous phase, formed by the phase change.

Abstract: This invention relates to a read-only near-field optical disk using a zinc-oxide (ZnO) nano-structured thin film as the localized near-field optical interaction layer. This read-only near-field optical disk is a multi-layered body at least comprising; (a) a transparent substrate with pre-recorded pits or marks; (b) a reflection thin film; (c) a zinc-oxide (ZnO) nano-structured thin film which is capable of causing localized near-field optical interactions; (d) a first and a second protective and spacer layers formed above or below the localized near-field optical interaction layer, which are also made of transparent dielectric material. Ultrahigh density near-field optical readout can be achieved by localized near-field optical interaction between the zinc-oxide (ZnO) nano-structured thin film and the reflection layer on pre-recorded structure.