Abstract: An optical recording medium having a disconnected land and/or a groove thereby forming a control signal portion. The control signal portion may have therein a clock signal. The disconnect is formed by wobbling a laser beam while applying the laser beam to a photoresist layer formed on an original glass disk to cut circumferential grooves therein. The beam is wobbled in the radial direction to form a disconnect in the circumferential groove and simultaneously therewith a mark to disconnect a land between grooves.

Abstract: A glass substrate for a magnetic disk of the present invention is one in which a laser beam is irradiated on a main surface thereby forming a large number of protrusions thereon to form texture thereon, each of said protrusions being formed by a protruded portion having a convex shape, said glass having a composition in which 0.2 to 3 wt % of an oxide of a transition metal is contained and an absorption coefficient with respect to a wavelength of a light at 266 nm being within a range of 0.03 to 2 .mu.m.sup.-1, and by setting the absorption coefficient of the glass with respect to a wavelength of a light at 266 nm within a range of 0.03 to 2 .mu.m.sup.-1 and irradiating a laser beam having a wavelength in a range of ultraviolet rays selectively on the main surface of a glass substrate at predetermined intervals, texture comprising a large number of protrusions formed by protruded portions each having a small diameter and a convex shape is formed.

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: An optical disk of the present invention includes a transparent dielectric film formed on a light incident side of the disk on an opposite side of an optical recording film so as to sandwich the transparent substrate therebetween, for suppressing bimetallic effects caused by a difference in thermal expansion between an optical recording film formed on an optical recording surface and the transparent substrate, whereby changes in tilt against temperature changes can be suppressed. Further, by an optimal selection of a reflectance of the transparent dielectric film, unwanted reflection due to multi-interference can be reduced at the same time.

Abstract: An optical article made of a transparent polymer which includes terephthaloyl moieties, optionally, other aromatic diacid moieties; ethylene glycol moieties; isosorbide moieties; and, optionally, one or more other diol moieties, wherein the polymer has an inherent viscosity of at least about 0.35 dL/g as measured on a 1% solution (weight/volume) in o-chlorophenol at 25.degree. C.

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: Information-bearing discs are fabricated from a first disc and a second disc. The first disc has a first substantially planar surface and a second surface opposite to the first surface. The second surface has first information recorded on it by means of local changes in the distance of the second surface from the first surface. The second disc is thicker than the first disc and has opposite, substantially planar, third and fourth surfaces. The fourth surface may have second information recorded on it by means of local changes in the distance of the fourth surface from the third surface. The second disc is secured to the first disc so that the fourth surface faces the second surface.

Abstract: An optical disk having high density and excellent quality as well as compatibility with conventional disks is provided. This optical disk is comprised of a disk-shaped substrate formed with a cyclic olefin polymer as its main component and a light-curing resin layer formed on the disk-shaped substrate, wherein a pattern is formed on the light-curing resin layer based on given information. The same effect can be obtained using a heat-curing resin in place of the light-curing resin. Optical disks having superior characteristics can be mass-produced.

Abstract: A babbitted bearing is disclosed. The babbitted bearing includes a bearing backing and a layer of iron electroplated to the backing. A layer of babbitt material is bonded to the layer of electroplated iron. The electroplated layer provides a favorable bond between the babbitt material and the bearing backing.

Abstract: A dual-layer DVD disc that does not require a stamping step (typically, as part of the 2P prior art manufacturing process) during its manufacture. A polycarbonate substrate is molded and coated with a semireflective data layer in the usual way. A PMMA substrate is molded and coated with a fully reflective data layer. Adhesive is placed on the semireflective data layer, and the fully reflective data layer is transferred from its PMMA substrate to the polycarbonate substrate. The polycarbonate substrate thus ends up with two data layers in conformance with the DVD specifications, and the PMMA substrate can even be recycled for another use.

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 information mediumis made up of a transparent substrate, on which are formed a dye recording layer of at least one dyestuff, a reflective layer of metal, and a protective layer in sequence, wherein said protective layer is formed from a plurality layers of resin which are formed sequentially. Further, the reflective layer is made of silver, and the dye recording layer is made of a material which does not contain iodine ion. The protective layer contains a material for trapping molecules and/or ions which corrode the reflective layer. For instance, a metal powder or porous pigment is contained in the protective layer, which is active on or absorbs the molecules and/or ions corroding the reflective layer.

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: Prevented is the reliability loss in phase change optical recording media during high-temperature storage, and also prevented is the phenomenon of self-erase by which a part of record marks having been formed in the media are erased due to the lateral heat diffusion into the recording layer while recording laser beams are irradiated to the media. The optical recording medium disclosed has a recording layer of a phase change type and is applied to driving units for overwriting it at a linear velocity of V.sub.0. The medium is so designed as to satisfy the requirement of 1<V.sub.max /V.sub.0 <1.5, where V.sub.max indicates the linear velocity at which the medium being overwritten has a highest C/N ratio.

Abstract: An optical information recording medium comprising a substrate provided with periodically wobbling guide grooves with a track pitch of 1.6.+-.0.1 .mu.m, and a lower protective layer, a phase-change type recording layer, an upper protective layer and a reflective layer formed in this sequence on the substrate, for recording, retrieving and erasing amorphous marks in the guide grooves by modulation of light intensity of at least two levels by means of a focused light having a wavelength of 780.+-.30 nm applied from the side of the substrate opposite to the recording layer side so that a crystalline state with a reflectance of from 15 to 25% is an unrecorded state, and an amorphous state with a reflectance of less than 10% is a recorded state, wherein the grooves have a depth of from 25 to 45 nm and a width of from 0.4 to 0.6 .mu.m.

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: An optical information recording medium comprising a substrate provided with periodically wobbling guide grooves with a track pitch of 1.6.+-.0.1 .mu.m, and a lower protective layer, a phase-change type recording layer, an upper protective layer and a reflective layer formed in this sequence on the substrate, for recording, retrieving and erasing amorphous marks in the guide grooves by modulation of light intensity of at least two levels by means of a focused light having a wavelength of 780.+-.30 nm applied from the side of the substrate opposite to the recording layer side so that a crystalline state with a reflectance of from 15 to 25% is an unrecorded state, and an amorphous state with a reflectance of less than 10% is a recorded state, wherein the recording layer is a thin film of an alloy of My.sub.y (Sb.sub.x Te.sub.1-x).sub.1-y where 0.ltoreq.y<0.3, 0.5<x<0.

Abstract: This invention provides an optical recording medium complying with the DVD standards, having high sensitivity, possessing high dye film stability, having a high C/N ratio during high density recording, and being capable of reducing jitter components contained in reproduced signals, by finding an organic dye thin film and a medium configuration which can be adapted for a short wavelength semiconductor laser (wavelength 500 to 700 nm) and which are satisfactory in optical characteristics, and chemical, photochemical, physical and thermal stability, the optical recording medium comprising at least a recording layer and a metallic reflecting layer laminated on the surface of a grooved resin substrate transparent to laser light; wherein the recording layer comprises an organic thin film consisting essentially of a styrylcyanine dye of a specific structure and adapted for a short wavelength laser.

Abstract: A laminated composite material, and a method of improving the surface hardness of laminated composite materials, wherein selected regions of the carrier material of the laminated composite system are treated with high-energy beams, and the temperature control is designed in such a manner that the rays penetrate into a maximum a 0.1-fold the entire thickness of the carrier material. The temperature increase in the region of the sliding material is a maximum of 80% of the melting temperature of the lowest melting constituent of said material. The laminated composite material with a rear steel substrate surface can be post-hardened. The steel substrate has at least in one part of the surface facing away from the function layer a level of hardness increased by a factor of 1.5 or more than at a depth which corresponds substantially to 0.1-fold of the thickness of the steel substrate.

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 digital recording medium, such as a compact disc, having a substrate, a reflective layer and a protective layer includes a near infrared fluorophore in one of the layers. The near infrared fluorophore can be incorporated into the CD by coating, admixing, blending or copolymerization and in an amount to impart a detectable fluorescence from the fluorophore when exposed to electromagnetic radiation having a wavelength ranging from about 670 nanometers (nm) to about 1100 nm. A method of marking a CD with an invisible marking and an apparatus for detecting the fluorophore is further provided.

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 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 method is provided for manufacturing a diamond-like carbon (DLC) coated optical phase-change recording medium for use with near-field optical head devices and which exhibits superior wear resistance and improved lifetime. According to the method, the surface of a composite optical phase-change media structure deposited onto a substrate is subjected to ion beam deposition of a DLC over-coat to a thickness of no greater than about 450 .ANG.. Preferably the DLC is ion beam deposited onto the phase-change recording layer at the surface of the medium structure or onto a germanium-containing adhesion-promoting interlayer to achieve the desired adhesion of the DLC to the surface of the medium structure.

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 information recording carrier has a substrate with at least one fine pattern row. On the substrate, a recording layer, a delamination-proof layer and a protective layer are sequentially superposed. In manufacturing, firstly, the recording layer is formed on the substrate. A first resin is then applied onto the recording layer. The first resin is then cured to form the delamination-proof layer. A second resin is next applied onto the delamination-proof layer. The second resin is then cured to form the protective layer.

Abstract: An electrical conductor has a copper base substrate coated with a tin base coating layer. To inhibit the formation of a copper/tin intermetallic and the resultant depletion of the free, unreacted, tin utilized as an oxidation and corrosion barrier, a barrier is interposed between the substrate and the coating. In a first embodiment, the barrier is formed from multiple constituent layers, at least one of which is copper. The thickness ("y") of the copper layer is dependent on the anticipated service temperature and satisfies the equation y=(-1.52+0.0871x+0.00859 t).+-.50% where t=anticipated time at the service temperature, x=anticipated service temperature (Celsius), and y=the thickness of the copper layer in microinches. In a second embodiment, the barrier layer is formed from one or more constituent layers, at least one of which is iron or iron base.

Abstract: A composition suitable for forming an optical information recording layer for carrying out recording and readout with laser beams, which comprises at least one cyanine dye, and at least one leuco compound of formulae (VII) or (VIII); and optionally, at least one aminium compound of formulae (IV) or (V).

Abstract: An optical disc comprising a disc having a signal- recording layer, wherein a treated layer having a surface electric resistance of from 1.times.10.sup.3 to 1.times.10.sup.13 .OMEGA. is formed on the signal-recording layer, and the surface of the treated layer is subjected to electrophotographic printing. The optical disc can be desirably used as an optical disc, in which digital signals can be recorded, reproduced or erased, such as a digital audio disc, such as a compact disc, a video disc, or a CD-ROM.

Abstract: A transparent protective cover for the play side of an optical disc is made of poly-carbon film. The protective cover is annular in shape and is appropriately sized to fit the various disc formats. There is provided an inner crevice or groove that fits the inner molding of a disc allowing for greater structural integrity and which assists in the placement of the protector on the disc. The device is attached to the disc using several clips that are located around the perimeter.

Abstract: An optical recording medium having at least one aluminum nitride and silicon nitride composite dielectric layer is provided. The amount of aluminum nitride in the dielectric layer, x, is more than zero and less than or equal to about 95 mol %. The amount of silicon nitride in the layer is represented as (100-x) and is equal to or greater than about 5 and less than 100 mol %. The refractive index of the composite dielectric layer is between about 1.70 and 2.15. The composite dielectric layer is sandwiched between a transparent support such as a plastic transparent support and an optical recording layer adapted to be irradiated by laser light in order to read, write or erase information in order to protect the recording layer.

Abstract: A master disk used in the manufacturing of optical disks and having a substrate and a photoresist layer coated on the substrate. The method for manufacturing the master disk includes the steps of: coating a first photoresist layer on a substrate; exposing the first photoresist layer according to patterns of a groove formation recess and a land formation protrusion corresponding to a groove and a land, respectively; etching the exposed substrate and the first photoresist layer, to thereby form the groove formation recess and the land formation protrusion on the substrate; coating a second photoresist layer on the substrate, to thereby form the groove and the land at positions corresponding to the groove formation recess and the pit formation protrusion, respectively; exposing the second photoresist layer according to a pattern of a pit where predetermined information is recorded; and etching the second photoresist layer, to thereby form the pit on the groove and the land.

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: The invention includes a method of manufacturing a fluorescent 3-D optical memory device implementing an active medium capable of storing information at high information density, and an optical memory device manufactured by this method. The active medium employed in the present invention is a material capable of existing in at least 2 isomeric forms. Transition from one form to another can be induced upon illuminating this material by a "writing" electromagnetic radiation having a first spectrum. At the same time the other isomeric form is capable of fluorescence upon illuminating this material by a "reading" electromagnetic radiation with a second spectrum. By virtue of illuminating with a radiation having the first spectrum there are created elemental cells within a medium material, containing substantially the same isomeric form thereof, which can be either that form which is capable of fluorescence or the other one which is not.

Abstract: A disc substrate molding metal mold apparatus adapted for molding synthetic resin material to carry out molding of disc substrate of an information signal recording medium. This metal mold apparatus is adapted so that smoothing layers of metal are integrally formed on the molding plane surface sides of a first metal mold serving as the fixed side and a second metal mold serving as the movable side which are butted to each other to constitute a molding portion for molding disc substrate, and uneven patterns corresponding to information signals, etc. formed at the disc substrate are directly formed at the metallic layers, thus to carry out molding of disc substrate in which the surface is flattened with high accuracy, and uneven patterns of the metal mold side are transferred without allowing local undulations and/or projections occurring on the disc surface to take place.

Abstract: A photopolymerizable composition comprising(A) 100 parts by weight of a mixture of (meth)acrylic acid ester monomers,(B) from 0.1 to 5 parts by weight of a surfactant having a perfluoroalkyl group and represented by the general formula (1)CF.sub.3 (CF.sub.2).sub.n AM (1)wherein A represents --CO.sub.2 -- or --SO.sub.3 --, M represents an alkali metal, and n is an integer of 3 to 9, and(C) from 0.2 to 10 parts by weight of a photopolymerization initiator, and a plastic optical disk provided with a cured coating of the photopolymerizable composition on at least one side thereof.

Abstract: A molded thermoplastic resin disc substrate specially adapted for use with floating head type recording/reproduction apparatus is provided. The molded disc substrate has surface smoothness characteristics which are the same or better than are provided with mirror polished aluminum discs. The molded disc substrates include a floating head scanning surface wherein the maximum projection height or maximum surface irregularity is less than about 50 nm to reduce or eliminate damage to either the disc or floating head caused by unwanted collisions between them. In a preferred embodiment, the molded disc substrates are molded from a thermoplastic resin composition containing 10000 particles/gram or less of particles having a particle diameter of 0.5 .mu.m or more. In a preferred embodiment, control of particle size and content is achieved by subjecting the resin molding composition to a sequence of filtering steps using filters of decreasing mesh size.

Abstract: A write-once-read-many type optical disk and a method for fabricating the same. The write-once optical disk includes a thin Fe--Zr--H recording layer formed on a substrate.

Abstract: An optical recording medium including a substrate which transmits light, which has a main surface, and which has a groove defined in the main surface; a recording layer formed on the main surface; and a metal reflection layer formed on the recording layer, wherein the recording layer is a thin film comprised of organic dye, contains at least one cyanine dye represented by general formula (I) as a main constituent, and is capable of corresponding to short-wavelength laser beam: ##STR1## where X- represents an iodide ion, a bromide ion, a perchlorate ion, a borofluoride ion, a tetrafluorophosphate ion, a tetrafluoroantimonate ion, a methylsulfate ion or a methylbenzenesulfonate ion; one of R.sub.1 or R.sub.2 represents a C.sub.3-18 substituent having an unsaturated bond, and another one of R.sub.1 and R.sub.2 represents a C.sub.3-18 substituent having one of an unsaturated bond, an alkyl group, an aryl group or an alkoxy group; Y.sub.1 and Y.sub.

Abstract: An improved optical recording medium is provided, and includes a surface of the optical recording medium having at least pits and grooves formed therein, a recording layer formed adjacent the surface of said optical recording medium, and a light transmissive layer formed adjacent the recording layer. Information is recorded and/or reproduced by irradiation of light from an optical pickup employing an objective lens having a numerical aperture of 0.7 or larger through the light transmission layer. At least a surface layer of said light transmissive layer is formed of a material having a Young's modulus of 70 GPa or larger thereby greatly reducing or eliminating scratches from the surface of the optical recording medium while allowing for an increase in the storage capacity of the optical storage medium.

Abstract: A triple substrate optical disk comprises a center substrate layer, a top substrate layer, a bottom substrate layer, a top adhesion layer bonding the top substrate layer to the center substrate layer and a bottom adhesion layer bonding the center substrate layer to the bottom substrate layer. The center substrate layer has a center substrate containing a top surface and a bottom surface thereof, a first recording layer deposited on the top surface of the center substrate and a second recording layer deposited on the bottom surface of the center substrate. The top substrate layer includes a top substrate and a third recording layer, wherein the top substrate has a top surface and a bottom surface thereof and the third recording layer is deposited on the bottom surface of the top substrate.

Abstract: A first dielectric layer, a second dielectric layer, a third dielectric layer, a recording layer, a fourth dielectric layer, and a reflective layer are provided in that order on a substrate to constitute a phase-change type optical disk. The first dielectric layer, the second dielectric layer, and the third dielectric layer are constructed to satisfy the relationships: n1>n2 and n3>n2 wherein n1 represents the refractive index of the first dielectric layer, n2 represents the refractive index of the third dielectric layer, n3 represents the refractive index of the second dielectric layer. According to the above construction, the light reflectance of the amorphous area can be increased to lower the light absorption of the amorphous area, realizing inhibition of cross erasing. Further, since no light absorptive layer is present between the substrate and the recording layer, the temperature rise around the surface of the substrate can be inhibited to reduce the thermal deformation of the substrate.

Abstract: An optical information carrier is in the form of a composite laminate having a carrier foil. The underside and the top side of the carrier foil are provided with optically effective structures. The carrier foil is approximately transparent for light in a predetermined spectral range. The structures allow light impinging on the top side to penetrate at least partially into the composite laminate. The structures on the underside are microscopically fine relief structures which are covered with a base layer whose refractive index differs from the refractive index of the carrier foil in at least a portion of the electromagnetic spectrum so that the structures on the underside at least partially reflect and diffract the light which has penetrated into the composite laminate. The structures on the top side in turn modify the diffracted light. The interplay of the two structures provides manifold characteristic optical effects such as moire effects and light guide effects.

Abstract: Disclosed is a Cu--Pb alloy bearing and a producing method thereof. The Cu--Pb alloy bearing consists of a backing metal layer and a Cu--Pb bearing alloy layer which is bonded to the backing metal layer and whose matrix contains dispersed Pb-phase grains. Within an at least 30 .mu.m thick surface region of the Cu--Pb bearing alloy layer, the Pb-phase grains comprise at least one of In and Sn in an amount or a total amount of not less than 2 wt %, respectively, which are elements added into the Pb-phase grains by migration.

Abstract: An optical recording medium has a substrate and a recording layer which is formed on the substrate and contains an azo metal chelate compound including an azo moiety of formula (I) and a bivalent or trivalent metal; ##STR1## wherein X is OH group, CooH group or CONH.sub.2 group; Y is a residual group forming a heterocyclic ring in combination with nitrogen atoms bonded thereto; and Z is a residual group forming an aromatic ring in combination with carbon atoms bonded thereto. In addition, there is provided a method of recording information and reproducing the information using the above-mentioned optical recording medium.

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: The present invention provides a method for internally damping a rotatable storage article which is subject to resonant vibrations. More specifically, the present invention provides a method of improving the damping properties of a rotatable storage article by introducing a viscoelastic material as an inner layer(s) of the rotatable storage article. The invention also provides the damped rotatable storage articles themselves.