Abstract: A description is given of a rewritable optical information medium having an IPIAIM stack comprising a phase-change recording layer sandwiched between two dielectric layers, a light-absorbing layer of a material like Si, Ge, Mo, or W, a third dielectric layer, and a metal mirror layer. The light-absorbing layer reduces the difference in light absorption between the amorphous state and the crystalline state to a minimum, thus reducing the recording mark distortion. The presence of the light-absorbing layer in this position ensures that the optical phase difference between the amorphous and the crystalline state is almost zero, making the medium suitable for land-groove recording.

Abstract: An information recording medium comprising a substrate having a recording surface provided with emboss pits or guiding grooves, a reflective film formed on the recording surface of the substrate, and a first protective film formed on the reflective film. This information recording medium is featured in that both sides of the information recording medium are constituted by a first surface provided with the protective film and by a second surface formed opposite to the first surface, and that an irradiated light beam is irradiated through the first surface, a recorded information being reproduced based on changes in light intensity of the reflected light beam. The distance between the recording surface of the substrate and the light incident surface is smaller than a thickness of the substrate, and a surface roughness "R" of the light incident surface meets a relationship represented by the following formula (1):R.ltoreq..lambda./(8n) (1)wherein .lambda.

Abstract: A phase-change recording medium having a recording layer (4) made of a Ge--Sb--Te alloy, comprises an interface reflection control layer (3) provided on a laser beam incident side of the recording layer (4). The interface reflection control layer (3) has an extinction coefficient k and a refractive index n, simultaneously satisfying: k.gtoreq.0.22n+0.14, k.ltoreq.0.88n-0.19, and n.ltoreq.2.8. From the foregoing, it follows that the intensity ratio between the reflected wave from and the incident wave on the interface between the recording layer (4) and the interface reflection control layer (3) is led to a specified range.As a result, for the recording layer (4) the ratio (Ac/Aa) of the light absorption rate (Ac) in the crystalline state to the light absorption rate (Aa) in the amorphous state increases. Furthermore, the optical contrast also has a sufficiently high value. It is therefore possible to produce a high quality readout signal in recording by overwriting.

Abstract: A phase change type optical recording medium comprises a dielectric layer 1a, a dielectric layer 1b, a phase change type recording layer and a second dielectric layer in the described order. The recording layer satisfies Ac/Aa.gtoreq.0.8 where Ac is an absorption coefficient of the recording layer in a crystalline region and Aa is an absorption coefficient of the recording layer in an amorphous region. The dielectric layer 1a comprises ZnS--SiO.sub.2 as main components and the dielectric layer 1b comprises a metal nitride or ZnS--SiO.sub.2 having an SiO.sub.2 content of 40 to 80 mol % as main components. At least an area of the second dielectric layer that is in contact with the recording layer comprises a metal nitride, a rare earth oxide, silicon oxide or ZnS--SiO.sub.2 having an SiO.sub.2 content of at least 40 mol% as main components. However, an optical recording medium comprising a dielectric layer 1a having an SiO.sub.

Abstract: The present invention is to provide a method for manufacturing the PCE optical information recording disk under control of not only the crystallization velocity but also the complex index of refraction and thus the reflectance on the disk surface.The PCE optical information recording disk is suitable to be used under the constant angular velocity (the constant rotational numbers wherein the disk has a characteristic that the crystallization velocity is designed to become faster from inside area of the disk to outside area in the radical direction thereof under control of not only the crystallization velocity but also the complex index of refraction and thus the reflectance on the disk surface.

Abstract: A laminated material for a plain bearing includes a running layer characterized by a high degree of hardness and good embedding and adaptation properties and high corrosion resistance. The laminated material is provided with a bearing material applied by sputtering directly to a carrier material, the bearing material comprising a matrix material of copper or copper base alloy with finely divided lead inclusions. The matrix material is isotropically crystallized with polygonal grain shape. The mean crystallite diameter is 2-4 .mu.m and the grain size of the lead inclusions is 0.2-0.4 that of the crystallite diameter.

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.sub..gamma.1 In.sub..delta.1 Sb.sub..zeta.1 Te.sub..omega.1, where 0.01.ltoreq..gamma.1.ltoreq.0.1, 0.03.ltoreq..delta.1.ltoreq.0.08, 0.5.ltoreq..zeta.1.ltoreq.0.7, 0.25.ltoreq..omega.1.ltoreq.0.4, and .gamma.1+.delta.1+.zeta.1+.omega.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: The optical recording medium of this invention includes: a first substrate having a first information surface; a semitransparent reflection film formed on the first information surface of the first substrate; a second substrate having a second information surface; a reflection film formed on the second information surface of the second substrate; and an adhesive layer for adhering the first substrate and the second substrate so that the first information surface and the second information surface face each other, wherein the thickness of the first substrate is 0.56 mm or more, the thickness of the adhesive layer is 30 .mu.m or more, and the total thickness of the first substrate and the adhesive layer is 0.68 mm or less.

Abstract: An information recording medium which includes at least a recording layer, and first and second metallic layers disposed on an opposite side of an energy beam incident side of the recording layer and having different compositions, and in which the first one of the first and second metallic layers located closer to the recording layer contains Al, Ag, Au, Pt and Pd as its main components and a sum of contents of these atoms is 60% or more. Thereby recording and reproducing of information can be realized with a high reliability.

Abstract: Disclosed is a phase change recording medium comprising a crystal section and an amorphous section, characterized in that the difference in reflectivity between the crystal section and the amorphous section is, for example, 15% or more when light with a wavelength of .lambda..sub.1 is applied and the difference in absorptivity between the crystal section and the amorphous section is, for example, 5% or less when light with a wavelength of .lambda..sub.2 is applied. Recording using light with a wavelength of .lambda..sub.2 brings about few opportunities of occurrence of cross-erasure because of a small difference in absorptivity between the crystal section and the amorphous section. Reproduction using light with a wavelength of .lambda..sub.1 after the recording using light with a wavelength of .lambda..sub.2 results in the production of satisfactorily regenerative signals because of a large difference in reflectivity between the crystal section and the amorphous section.

Abstract: A sputtering target for fabricating a recording layer of a phase-change type optical recording medium contains a compound or mixture including as constituent elemets Ag, In, Te and Sb with the respective atomic percent (atom. %) of .alpha., .beta., .gamma. and .delta. thereof being in the relationship of 2.ltoreq..alpha..ltoreq.30, 3.ltoreq..beta..ltoreq.30, 10.ltoreq..gamma..ltoreq.50, 15.ltoreq..delta..ltoreq.83 and .alpha.+.beta.+.gamma.+.delta.=100, and a method of producing the above sputtering target is provided. A phase-change type optical recording medium includes a recording layer containing as constituent elements Ag, In, Te and Sb with the respective atomic percent of .alpha., .beta., .gamma. and .delta. thereof being in the relationship of 0<.alpha..ltoreq.30, 0<.beta..ltoreq.30, 10.ltoreq..gamma..ltoreq.50, 10.ltoreq..delta..ltoreq.80, and .alpha.+.beta.+.gamma.+.delta.

Abstract: A rewritable optical information medium has a phase-change recording layer on the basis of an alloy of Ge--Sb--Te, which composition is situated within the pentagonal area PQRST in a triangular ternary composition diagram. These alloys show a complete erase time of 50 ns or less. CET-values below 45 ns are obtained with alloys situated on the tie-line connecting Te and the compound GeSb.sub.2 Te.sub.4 within the area PQRST. Such a medium is suitable for high speed recording (i.e. at least six times the CD-speed), such as for DVD-RAM and optical tape.

Abstract: An archival medium, such as a compact disc, is made of a metal such as aluminum which is mechanically gained with particulate material under conditions that embed particulate material into the surface of the medium and visibly imageable by selective exposure to infrared laser radiation. A mechanically grained aluminum medium can also be anodically oxidized under conditions that do not impair the ability of the substrate to be laser imaged. The archival medium can be coated with opaque and transparent polymer coatings before or after imaging for security and/or protection. The coating can be a laser ablatable coating to provide a tamper-proof medium.

Abstract: An optical data recording medium utilizing reversible inter-crystalline-amorphous phase changes for recording, reproducing and erasing data as phase changes of a recording film caused by laser beam irradiation. The medium is formed by a lamination of a transparent substrate having tracking guide grooves for laser beam tracking, a base film formed on the substrate, a first protective film formed on the base film, a phase change type recording film formed on the first protective film, a second protective film formed on the recording film, and a reflecting film formed on the second protective film. Thus formed, the medium improves the over-writing characteristics of phase change type optical discs and permits high density recording.

Abstract: An optical recording medium comprising a substrate having a pre-groove for focusing and tracking servo operation, and a recording film formed on the substrate, the recording film having optical properties which change in response to the application of at least one of a light beam or heat to a portion of the recording film.

Abstract: In an optical recording information recording medium of a structure having protection layers on both surfaces of a recording layer, overwrite cyclability is improved without deteriorating the reliability of recorded data.To achieve this, the first protection layer is deposited by a sputtering method from a target made of a mixture comprising ZnS and SiO.sub.2 without adding an O.sub.2 gas and a H.sub.2 gas to a sputtering atmosphere, the second protection layer is deposited by a sputtering method using a target made of a mixture comprising ZnS and SiO.sub.2 by adding an O.sub.2 gas and an H.sub.2 gas to the sputtering atmosphere.Especially, an optical information recording medium having a high reliability of recorded data and capable of overwriting of 300,000 cycles or more can be obtained, particularly, by controlling the partial pressure of the added O.sub.2 gas to 10.times.10.sup.-6 -50.times.10.sup.-6 Torr and the partial pressure of the added H.sub.2 gas to 20.times.10.sup.-6 -50.times.10.sup.

Abstract: An phase change optical medium compatible with a flying head can include a substrate, a reflective layer, a first dielectric layer, a phase change information carrying layer, a second dielectric layer and a lubricant layer. The structure and materials used both protect the phase change layer from mechanical damage due to impact and from information-altering heat generated by impact.

Abstract: The invention provides a method of fabricating an optical recording medium comprising a phase change type recording layer containing at least one element selected from In, Ag, Te and Sb. The recording layer is formed by a sputtering technique wherein sputtering is carried out while an inert gas and an oxygen gas are introduced in a vacuum chamber in a sputtering system, so that the number of overwritable cycles can be increased by simple means.

Abstract: A phase-change optical recording medium has a substrate, and a lower heat-resistant protective layer, a recording layer capable of recording and erasing information by utilizing changes in the phase of a phase-change recording material in the recording layer, an upper heat-resistant protective layer and a light reflecting and heat dissipating layer, which are successively overlaid on the substrate in this order, the recording material including Ag, In, Sb and Te as the main elements, at least one additional element selected from the group (1) consisting of B, C, N, Al, Si and P, and at least one additional element selected from the group (2) consisting of halogen atoms and alkali metal elements.

Abstract: A phase change type optical recording medium of Ge--Sb--Te system wherein number of overwritable operation has been increased is provided. The optical recording medium has a substrate and a recording layer of phase change type on the substrate, and the recording layer contains Ge, Sb and Te as its main elements, and at least one of Ag and Au in total content of 0.2 to less than 2.5 at % (excluding 2.5 at %).

Abstract: A method for soldering electronic components capable of withstanding high temperature applications. A solder having a composition in the range between 83 and 87% lead, between 8.5 and 11.5% antimony, and the balance of tin provides superior results. The solder uniquely provides a sufficiently low melting point to enable mass flow without destruction of plastic package parts, and a sufficiently high melting point to achieve 200 degrees C. operation. Good mechanical strength is achieved while providing sufficient creep to permit differential expansion between components and a printed wiring board. A heavy solder layer is coated on a printed wiring board and is oxidized to generate a thin solderable layer. Manufacture of the circuit board can be performed with conventional techniques such as wave soldering, hand soldering, solder printing, solder dispensing, and solder pre-forms.

Abstract: An optical recording medium of phase change type, and in particular, a dual side medium prepared by adhering two single side media is provided. In this medium, deformation of record marks generated in the overwriting due to difference in light absorption between the record marks and the region other than the record marks is prevented by providing a reflective layer of high light transmission, and increase in jitter and failure of track servo and focus servo caused by uneven coating of the adhesive layer and the resin protective layer are prevented. The optical recording medium comprises a substrate, a recording layer of phase change type on the surface side of the substrate, and a reflective layer and a light absorption layer disposed in this order on the surface side of the recording layer.

Abstract: In an optical disk obtained by pasting two substrates, air bubbles and the like are removed from an adhesive layer between the substrates pasted together, and the thickness irregularity of the adhesive layer is suppressed to an allowable value or less. A spacer having a predetermined thickness is concentrically placed on a substrate. An adhesive is applied onto a surface of the substrate on which the spacer is placed. Another substrate is placed on the surface of the substrate on which the adhesive is applied. The substrates are rotated about the spacer at a high speed. The excessive adhesive sandwiched between the substrates is expelled, together with air bubbles and the like, by using the centrifugal force produced by the rotation. With this process, an adhesive layer having a thickness determined by the thickness of the spacer is left between the two substrates.

Abstract: An optical recording medium has a high hardness layer, first dielectric layer, recording layer, second dielectric layer and reflective layer. The hardness of the high hardness layer is larger than the hardness of the first dielectric layer, and the thickness of the second dielectric layer is in the range of 3 to 50 nm. Such a rewritable phase change type optical recording medium may show reduced degradation in the write-start portion and write-end portion of frequently rewritten sectors, and have good jitter characteristics.

Abstract: An optical recording medium of phase change type which exhibits an increased number of overwritable operations is provided. The optical recording medium comprises a substrate, and a first dielectric layer, a recording layer, a second dielectric layer, and a metal reflective layer disposed on the substrate in this order, and the first dielectric layer comprises a dielectric layer 1a on the side of the substrate and a dielectric layer 1b in contact with the recording layer. The dielectric layer 1a comprises ZnS--SiO.sub.2, and the dielectric layer 1b comprises Si.sub.3 N.sub.4 and/or Ge.sub.3 N.sub.4. The second dielectric layer may comprise a single layer of ZnS--SiO.sub.2, SiO.sub.2 or oxide of a rare earth metal. The second dielectric layer may also comprise a laminate of a dielectric layer 2a comprising ZnS--SiO.sub.2 on the side of the substrate and a dielectric layer 2b comprising SiO.sub.2 or oxide of a rare earth metal on the side of the reflective layer. The dielectric layer 1b has a thickness of 0.

Abstract: A self-lubricating bearing material is described, as well as a plain bearing of such a bearing material, the performance of which, under lubricant-free conditions, is so markedly improved that pv values of up to 6 MPa/m/s are achieved in an average load and speed range. The self-lubricating bearing material comprises a PTFE-containing polymer matrix with fillers comprising PbO and at least one metal fluoride. The PbO content is from 15-55 vol. % and the metal fluoride content is from 0.1-14 vol. %. Preferred metal fluorides are CaF.sub.2, PbF.sub.2 and MgF.sub.2. The addition of further fillers such as hard materials, pigments or fibrous material is possible. The proportion of further additives may amount to up to 40 vol. % of the PbO/metal fluoride fillers.

Abstract: A system for soldering electronic components capable of withstanding high temperature applications. A solder having a composition in the range between 83 and 87% lead, between 8.5 and 11.5% antimony, and the balance of tin provides superior results. The solder uniquely provides a sufficiently low melting point to enable mass flow without destruction of plastic package parts, and a sufficiently high melting point to achieve 200 degrees C. operation. Good mechanical strength is achieved while providing sufficient creep to permit differential expansion between components and a printed wiring board. A heavy solder layer is coated on a printed wiring board and is oxidized to generate a thin solderable layer. Manufacture of the circuit board can be performed with conventional techniques such as wave soldering, hand soldering, solder printing, solder dispensing, and solder pre-forms.

Abstract: A high density optical recording medium having wide-width grooves capable of reliable tracking is provided. The optical recording medium is formed with the wide-width grooves 12 in which a width g of the groove 12 is larger than a width L of a land between the grooves. The lands 11 and the grooves 12 are formed so that a track pitch Tp is less than 1 .mu.m, and a land height h from a groove bottom surface 13 satisfies [(.lambda./(8n)).multidot.Ltan.theta.]/[Ltan.theta.-(.lambda./(8n))].ltore q.h.ltoreq.[(.lambda./(5n)).multidot.Ltan.theta.]/[Ltan.theta.-(.lambda./(5 n))] with respect to a wavelength .lambda. of a reproducing light beam and a refractive index n of a substrate. An angle of inclination of a groove side wall is represented by .theta., and the refractive index of the substrate is represented by n.

Abstract: A rewritable optical information medium has a phase-change recording layer (3) on the basis of an alloy of Ge-Sb-Te-O, having the composition (Ge.sub.a Sb.sub.b Te.sub.c).sub.1-d O.sub.d, wherein:a+b+c=10.0001 a d a 0.035The addition of oxygen considerably speeds up the crystallization rate of Ge-Sb-Te materials. Such a medium is suitable for high speed recording (i.e. at least eight times the CD-speed), such as for DVD-RAM and optical tape. The amount of oxygen in the recording layer (3) can be used to tune the crystallization rate to the desired value.

Abstract: A connective medium is provided for use in ball grid assemblies for detachable connections between electronic devices and circuit boards. The medium includes novel, discrete spheres defining an inner metallic, spherical core and one or more outer, electrically conductive concentric, hard and non-deformable metallic layers of nickel, copper or alloys thereof and a coating of silver or gold thereon.

Abstract: The present invention provides an optical recording medium which incorporates an inorganic based recording layer which has a high reflectance, sufficient for reproduction compatibility on devices such as CD-ROM drives, as well as a high degree of modulation between the state prior to recording and that after recording, as well as an information recording method therefor.

Abstract: An optical recording medium comprises a substrate and a multilayer structure on the substrate. The multilayer structure comprises a phase change type recording layer and a pair of dielectric layers, at least one of which contains zinc sulfide optionally with silicon oxide. When a depth profile of the multilayer structure in a thickness direction thereof is found by Auger electron spectroscopy, a region having an intensity ratio S/Zn of 2 or lower exists across a thickness of at least 6.0 nm, calculated as SiO.sub.2, from the vicinity of an interface between the dielectric layer and the recording layer into the recording layer. In the vicinity of the interface between the dielectric layer and the recording layer, there is also a region having an intensity ratio S/Zn vs. O/Si relation that satisfies S/Zn<O/Si.

Abstract: A composite wire made by coating a core material by solid-phase extrusion of a uniform layer of a corrosion resistant metal onto the core material. The metal includes lead and has uniform, small and longitudinally oriented grains.

Abstract: The present invention aims at improving C/N, erasing ratio, modulation factor, recording sensitivity, and recording/erasing repeatability characteristics of a phase-change type optical recording medium.The recording layer of the optical recording medium is therefore formed of a chalcopyrite type compound having a composition represented by the formula:Au.sub..alpha. In.sub..beta. Sb.sub..gamma. Te.sub..delta.wherein0 atomic %<.alpha..ltoreq.25 atomic %;1 atomic %.ltoreq..beta..ltoreq.18 atomic %;30 atomic %.ltoreq..gamma..ltoreq.75 atomic %; and15 atomic %.ltoreq..delta..ltoreq.45 atomic %;in which 99 atomic %.ltoreq..alpha.+.beta.+.gamma.+.delta..ltoreq.100 atomic %. Further, this optical recording medium is used such that the relative speed of the recording layer at recording/erasing is from 1 m/sec to 20 m/sec relative to the light beam.

Abstract: An optical information recording medium for recording, retrieving and erasing mark length-modulated amorphous marks, which comprises a substrate, and a lower protective layer, a phase-change recording layer, an upper protective layer and a reflective layer having a thickness of from 40 to 300 nm and a volume resistivity of from 20 to 150 n.OMEGA..multidot.m, formed in this sequence on the substrate.

Abstract: Methods and apparatus for making optical discs (e.g., for use in digital versatile discs ("DVDs") are provided. An optical disc made in accordance with this invention includes at least one roughened surface portion to mask any manufacturing irregularities and thereby improve the appearance of the disc and, if the disc is used in a DVD, then also the DVD. The method includes roughening a section of a mold in contact with molten plastic, molding an optical disc with that mold so that at least one side of the optical disc has a roughened surface portion, and if the disc is used in a DVD, securing the disc to another disc with adhesive to form a DVD.

Abstract: An optical recording medium of phase change type with an increased number of overwritable operations and method for preparing such an optical recording medium is provided. In the optical recording medium of phase change type whose rate determining stage in the production has been the initialization of the recording layer, the time required for the production is reduced, and stable recording/reproducing properties are realized from the first overwriting operation. The optical recording medium comprises a transparent substrate and a recording layer on the transparent substrate.

Abstract: A multilayer material is described, whose overlay exhibits improved hardness and improved wear-resistance. The multilayer material includes an overlay, which contains 8-18.5 wt. % tin and 2-16 wt. % copper, the balance being lead, wherein the tin is present as a finely crystalline deposit completely homogeneously distributed in the lead. A process for producing sliding elements in which the overlay of lead-tin-copper is applied to the prefabricated semi-finished product by electroplating provides that a ternary, fluoroborate-free electroplating bath is used without brighteners and with the addition of fatty acid polyglycol ester and a grain refining agent including a carboxylic acid.

Abstract: An optical disk can provide a sufficiently wide power margin for a recording power even when the optical disk has a high-recording density. The optical disk has a transparent substrate on which a recording layer in which information can be rewritten by at least irradiation of laser beam, a dielectric layer and a thermal conduction control layer are sequentially deposited. The thermal conduction control layer comprises a first low thermal conductivity layer, a first high thermal conductivity layer, a second low thermal conductivity layer and a second high thermal conductivity layer sequentially deposited thereon.

Abstract: An optical recording medium is provided which achieves a higher recording capacity. This optical recording medium includes a base formed of thermoplastic resin which has a thickness ranging from between approximately 0.3 to 1.2 nm, a guide groove formed on the base, at least a reflective film and a phase-change recording layer successively formed on the guide groove, arid a light transmissive layer having a thickness ranging from between approximately 3 to 177 .mu.m. In this optical recording medium, the unevenness .DELTA.t of the thickness of the light transmission layer is set within the range of:.DELTA.t.ltoreq..+-.5.26(.lambda./N.A..sup.4)(.mu.m)wherein N.A. represents a numerical aperture of an optical head device of the optical disk recording and/or reproducing apparatus and .lambda. represents the wavelength of laser light utilized by the optical disk recording and/or reproducing apparatus.

Abstract: A recordable element includes a substrate, an optical recording layer deposited on the substrate, a light reflecting layer deposited over the recording layer and an interfacial layer having a thickness in a range of 3 to 30 nm and interposed between the recording layer and the reflective layer, the optical recording layer containing Te.sub.a Ge.sub.b C.sub.c H.sub.d O.sub.e where a, b, c, d, and e are the atomic percents such that a+b+c+d+e=100, and wherein 10<a<40, 10<b<60, 5<c<35, 10<d<35, e.gtoreq.0; and the interfacial layer containing Ge.sub.w C.sub.x H.sub.y O.sub.z where w, x, y, and z are atomic percents such that w+x+y+z=100, and wherein 15<w<65, 5<x<35, 15<y<40, z.gtoreq.0. The recording element has its properties changed by heat treatment for a time and temperature selected so as to improve and stabilize its performance.

Abstract: An optical data storage medium transmissive to a laser beam and formed of a light transmissive substrate that provides mechanical support, and a light transmissive data substrate formed on the substrate. The data substrate is patterned to form block regions that block the laser beam from passing through, and pass regions that allow the laser beam to pass through, such that the blockage or passage of light through the optical storage medium reflects the type of data bits to be stored on the optical medium. In another embodiment a magneto-optical data storage medium which is also transmissive (or partly transmissive) to a laser beam includes a data magneto-optical data substrate formed on a substrate. The data substrate is recordable by patterning a magnetic domain with magnetic fields of opposite directions, such that each magnetic direction reflects the type of data bits to be stored on the optical medium.

Abstract: In a rewritable optical information recording medium, a transparent interference layer, a translucent interference layer, a lower protection layer, a recording layer, an upper protection layer, and a reflection layer are formed on a substrate in that order. The transparent interference layer has a reflectance which changes in accordance with a wavelength of a beam incident on the substrate, and the translucent interference layer has a light transmittance smaller than that of the transparent interference layer. In this constitution, by determining appropriate thicknesses of the above-mentioned layers, a reflectance of a non-recorded portion of the recording medium with respect to a reproducing beam can be increased. Further, reflectances of the non-recorded and recorded portions with respect to a recording and erasing beam can be decreased, so that it becomes easy to record and erase information in the recording medium.

Abstract: An information memory apparatus includes an information storage medium having a thin film formed as a recording layer or a superresolution reading mask layer on a substrate directly or via a foundation layer to record and/or reproduce information stored in the form of an atom configuration change caused by irradiation of an energy beam. The information storage medium includes reflective layers as well. The information memory apparatus further includes a laser used for at least recording. The laser has a wavelength. The light absorptance of the recording layer or mask layer of the medium in a crystalline state at the wavelength is greater than or equal to the light absorptance of the recording layer or mask layer of the medium in an amorphous state at the wavelength.

Abstract: An optical recording medium includes a substrate, a first protection layer formed on the substrate, a recording layer formed on the first protection layer, a second protection layer formed on the recording layer, and a reflection heat radiating layer formed on the second protection layer. The recording layer is of a phase-change type in which the recording layer is changed from an amorphous state to a crystal state by a temperature raising and cooling process by projecting a laser beam onto the recording layer. The recording layer has an interface portion interfaced with one of the first and second protection layers. The interface portion has a thermal conductivity lower than that of a remaining portion of the recording layer.

Abstract: A metallic backing layer such as steel covered by a functional layer of AlSn, AlPb, CuPb, CuSn or CuZn, applied by spraying in air, and a softer covering layer applied to the functional layer by chemical or electrolytic deposition exhibits improved corrosion resistance, running-in behavior and conformability.

Abstract: A description is given of an reversible optical information medium comprising a substrate, a first dielectric layer, a phase-change recording layer on the basis of Ge--Sb--Te, a second dielectric layer, and a metal mirror layer. The recording layer comprises an alloy having the composition Ge.sub.50x Sb.sub.40-40x Te.sub.60-10x in atom %, wherein0.166.ltoreq.x.ltoreq.0.444and wherein the layer thickness d.sub.3 of said recording layer ranges between 25 and 35 nm. Such a medium is suitable for high speed recording (i.e. at least twice the CD-speed), and has a large cyclability of at least 10.sup.5 direct overwrite cycles.

Abstract: A composite wire made by coating a core material by solid-phase extrusion of a uniform layer of a corrosion resistant metal onto the core material. The metal includes lead and has uniform, small and longitudinally oriented grains.

Abstract: An optical information recording medium is provided in which the active layer is a phase change material capable of absorbing energy and being converted between a substantially amorphous state and a substantially crystalline state. The active layer contains nitrogen, which may be in the form of a nitride or nitrides of the constituent elements of the active layer, or may be a nitrided surface thereof. The inclusion of nitrogen inhibits localized shifting of the active material, which leads to degradation of the recording/erase properties of the medium. The optical recording medium includes a substrate, onto which is deposited in sequence a first dielectric layer, a nitrogen-containing active layer, a second dielectric layer, and a metallic reflecting layer. The second dielectric layer is made thin, so that the cooling rate of the active layer is increased to form a more uniform amorphous state.

Abstract: The present invention provides an optical recording medium using an amorphous-crystalline phase-change for recording and erasing, wherein reflectivity of an optical recording medium-constituting recording film in an amorphous state is larger than that of the optical recording medium-constituting recording film in a crystalline state, or wherein absorptivity of an optical recording medium-constituting recording film in an amorphous state is smaller than that of the optical recording medium-constituting recording film in a crystalline state.