Abstract: An epitaxial wafer has a base material made of sapphire-SiC single crystal or the like, a III nitride underfilm including at least Al element epitaxially grown on the base material and a GaN film, preferably having a thickness of 50 Å or over, formed on the underfilm. In a fabricating a III nitride films on the epitaxial wafer, the oxidized surface layer of the GaN film is removed through etching process, and subsequently, the III nitride film is formed.

Abstract: Disclosed are compositions of matter which include a thin metallic and/or metallic oxide, nitride, carbide, silicide, boride, or sulfide coating disposed directly upon a polymeric substrate, in the absence of a carrier layer for the thin coating. Also disclosed are methods to make the composition and an apparatus to practice the method.

Abstract: A p-type zinc oxide film and a process for preparing the film is disclosed. In a preferred embodiment, the p-type zinc oxide film contains arsenic and is grown on a gallium arsenide substrate. The p-type zinc oxide film has a net acceptor concentration of at least about 1015 acceptors/cm3, a resistivity of no greater than about 1 ohm-cm, and a Hall mobility of between about 0.1 and about 50 cm2/Vs.

Abstract: A method for producing a stress-engineered substrate includes selecting first and second materials for forming the substrate. An epitaxial material for forming a heteroepitaxial layer is then selected. If the lattice constant of the heteroepitaxial layer (aepi) is greater than that (asub) of the immediate substrate layer the epitaxial layer is deposited on, then the epitaxial layer is kept under “compressive stress” (negative stress) at all temperatures of concern. On the other hand, if the lattice constant of the heteroepitaxial layer (aepi) is less than that (asub) of the immediate substrate layer the epitaxial layer is deposited on, then the epitaxial layer is kept under “tensile stress” (positive stress). The temperatures of concern range from the annealing temperature to the lowest temperature where dislocations are still mobile.

Abstract: A standard for calibrating and checking a nanotopography unit, includes a substrate and at least one structure which is deposited on the substrate. It has a lateral extent of 0.5 to 20 mm and a vertical extent of 5 to 500 nm and is bounded by edges which have a gradient of at most 1*10−3. There is also a method for producing the standard, with material being deposited on the substrate at an inhomogeneous deposition rate.

Abstract: This invention pertains to more sensitive and more stable electronic devices which can sense electrical and magnetic fields. The devices are characterized by InAs channels confined on both sides thereof by a wide band gap AlSb material; protective layers above the AlSb material; modulation doping above the AlSb material; and layers of the InAs channel material containing 1 to 99 mol percent antimony, with the channel material being deposited in the form of alternating monolayers of InSb and InAs, of a ternary mixture of InAsSb.

Abstract: A sliding bearing, which comprises a lining and a bismuth or bismuth-alloy overlay having improved compatibility and fatigue resistance is provided. The overlay is characterized by the following orientation. The relative ratio of the X-ray diffraction intensity I[hkl] of the bismuth or bismuth-alloy overlay defined below satisfies the following conditions (a) and (b): (a) the relative ratio of the X-ray diffraction intensity I[hkl] of planes other than the {012} planes is from 0.2 to 5 times as high as the ratio of the X-ray diffraction intensity I[012], namely, 0.2I[012]≦I[hkl]≦5I[012] (b) the relative ratio of the X-ray diffraction intensity I[hkl] of three or more planes other than {012} planes ranges from 0.5 to 2 times as high as the ratio of the X-ray diffraction intensity I[012], namely, 0.5I[012]≦2I[012].

Abstract: A p-type zinc oxide film and a process for preparing the film is disclosed. In a preferred embodiment, the p-type zinc oxide film contains arsenic and is grown on a gallium arsenide substrate. The p-type zinc oxide film has a net acceptor concentration of at least about 1015 acceptors/cm3, a resistivity of no greater than about 1 ohm-cm, and a Hall mobility of between about 0.1 and about 50 cm2/Vs.

Abstract: In one aspect, the invention includes a processing method, comprising: a) providing a substrate having a high aspect ratio opening therein; b) forming a metal-comprising layer over the opening; c) providing a first pressure against the metal-comprising layer; and d) ramping the pressure that is against the metal-comprising layer to a second pressure at a rate of from about 1 atmosphere per second about 100 atmospheres per second.

Abstract: The invention relates to a high-temperature-resistant component comprising a nickel-based or cobalt-based superalloy, in particular having a protective alloy selected from the class consisting of MCrAlY alloys. The component has an antioxidation coating comprising gallium. The invention also relates to a corresponding method of providing protection against oxidation.

Abstract: An optical information recording medium includes a first substrate; at least a first dielectric layer and a recording layer for signal recording provided on a surface of the first substrate; and a second substrate. The first substrate and the second substrate are assembled together in the state of being warped in planar symmetry and flattened. The first dielectric layer and the recording layer is interposed between the first substrate and the second substrate.

Abstract: To provide an optical disk with high mass producibility and excellent optical properties, mechanical precision, and mechanical strength, as well as a method for the simple and efficient manufacturing of this optical disk.Comprises a substrate 101 of an extrusion molded sheet of a material consisting primarily of a polyolefin polymer which has been processed into a disk, and a data recording medium surface which consists of a photocuring resin layer 102 formed on the substrate 101 and on which bumps have been formed based on prescribed data.

Abstract: A magnetic recording has very low warp characteristics but excellent film characteristics. Particularly, the recording medium has a high coercivity with a small range of coercivity distribution, with a warp characteristic below 3 .mu.m per radial inch. The medium is formed by heating a substrate at a high temperature with a temperature distribution on the substrate that is improved by the use of a heat distribution mask, which reduces the temperature distribution of the substrate to below .+-.3%.

Abstract: A reproducing layer, an intermediate layer, and a recording layer are successively stacked. The reproducing layer is made of a perpendicularly magnetized film whose domain wall coercivity is relatively smaller and whose domain wall mobility is relatively larger as compared with the recording layer around a reproducing temperature. When the reproducing layer, the intermediate layer, and the recording layer have Curie temperatures of Tc1, Tc2, and Tc3, Tc1, Tc2, and Tc3 satisfy a relationship of Tc2<Tc1<Tc3. Upon reproducing information, the reproducing layer is partially heated to more than the Curie temperature by irradiating with a light beam. This arrangement makes it possible to expand and reproduce a domain without causing a repetition of reproduction and to reproduce a signal having a period which is not more than an optical diffraction limit without reducing an amplitude of the reproduced signal, thereby dramatically improving a recording density.

Abstract: A mini-floppy disk or like information storage device is comprised of a circle of data storage medium having a central metal hub. In use, the hub is contacted with and driven by a magnetized spindle. The hub comprises a ferromagnetic substrate and a metal coating. The coating has magnetization B.sub.s which is less than the magnetization of the substrate. The coating is harder than the substrate, preferably greater than 400 DPH hardness number. The coating is deposited with an amorphous microstructure while the substrate is crystalline. The coating has a nodular surface texture and surface oxide film which provides improved adhesive bond strength, where the medium is joined to the hub. The coating preferably is an electroless plating deposit, comprised of nickel or cobalt base metal, with phosphorous or boron additive; most preferably it is nickel-11% phosphorous.

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: An abrasives composition comprises (i) one or more abrasives, (ii) one or more abrasion accelerators and (iii) water. The abrasive comprises intermediate alumina particles having a mean particle size of primary particles of 40 nm or less. The composition is used to produce a substrate by abrasion.

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: The invention relates to an optical recording medium, in particular to a compact disc, comprising the following layers:a) a transparent substrate with a spiral having an indented or protruding geometry; superposed byb) a recording layer; optionally superposed byc) a protective coating, wherein the recording layer comprises a partially transparent layer; superposed by a transparent buffer layer comprising a cross-linked material; superposed by a thick layer, said layers forming together a Fabry-Perot etalon.

Abstract: The invention relates to an article of manufacture comprising: a substrate composed of a superalloy containing chromium and a base element selected from the group consisting of iron, cobalt, and nickel; and an enrichment layer containing chromium and placed on the substrate. Therein, the enrichment layer comprises a continuous matrix composed of a gamma-phase solid solution of chromium in the base element. The invention also relates to the manufacture of such an article. The article may in particular be a gas turbine component.

Abstract: In accordance with the present invention, a glass substrate of a disk for recording information, containing oxides of rare earth elements and fine particles dispersed therein, and a disk for recording information and a disk apparatus for recording information using the glass substrate of the disk are provided. The glass substrate of the disk for recording information having preferable mechanical characteristics, as well as superior chemical stability, thermal stability, flatness, and transparency is provided, and a disk for recording information and a disk apparatus for recording information using the glass substrate of the disk are provided.

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: 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 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 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: 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: 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 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 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: A disk substrate fabricated front an inner substrate having a specific stiffness greater than about 7.6 Mpsi/gm/cc and an encapsulating layer deposited over the inner substrate. The inner substrate may include materials such as alumina, silicon carbide, beryllium, boron carbide, aluminum, and mixtures thereof. The encapsulating layer may be made from aluminum, magnesium, copper, zinc, and mixtures thereof. The disk substrate may additionally comprise a finishing layer deposited on the encapsulating layer fabricate from a material such as nickel or an alloy thereof.

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 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 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: 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: A material according to the invention is made of a glass whose transition temperature is 750 degrees Celsius or greater and used for a substrate for information recording media, and for example, the glass has an essential component made of any group chosen from SiO.sub.2 --Al.sub.2 O.sub.3 --MgO--CaO, SiO.sub.2 --Al.sub.2 O.sub.3 --MgO--Y.sub.2 O.sub.3, SiO.sub.2 --Al.sub.2 O.sub.3 --CaO--Y.sub.2 O.sub.3, SiO.sub.2 --Al.sub.2 O.sub.3 --MgO--CaO--Y.sub.2 O.sub.3, and SiO.sub.2 --Al.sub.2 O.sub.3 --M.sub.2 O.sub.3 (wherein M denotes a trivalent metal.). This material can form a substrate for information recording media, or more specifically, a substrate on which at least a magnetic layer is formed to constitute a magnetic disc.

Abstract: An optical memory material includes a two-photon storage component which can be written from a first to a second state in response to WRITE light, mixed with a signal component which fluoresces by one-photon absorption only at the written locations in response to READ light. The storage material may be a fulgide. The memory material may also include a frequency upconversion material to aid writing. Writing is performed by a spatial light modulator (SLM) with a dynamic focussing system, for concentrating sufficient power at WRITE locations for nonlinear two-photon absorption. Crosstalk is avoided during simultaneous writing in some embodiments, by spacing the individual WRITE beams apart by an integer number of inter-beam spacings, so that non-adjacent datels are written simultaneously in a "paragraph," and the non-written areas are written at a different time with different paragraphs.

Abstract: An optical information recording medium includes a substrate, and a light absorption layer formed thereon which includes a phthalocyanine compound (I), a phthalocyanine compound (II) and a phthalocyanine compound (III) as specified in the specification. This optical information recording medium can be produced by providing the light absorption layer, directly or via an intermediate layer, on a substrate with information pits and/or guide grooves being formed on the surface thereof by film formation coating, providing a light reflection layer, directly or via an intermediate layer, on the light absorption layer by vacuum film formation, and then providing a protective layer on the light reflection layer.

Abstract: In accordance with the present invention, a glass substrate of a disk for recording information, containing oxides of rare earth elements and fine particles dispersed therein, and a disk for recording information and a disk apparatus for recording information using the glass substrate of the disk are provided. The glass substrate of the disk for recording information having preferable mechanical characteristics, as well as superior chemical stability, thermal stability, flatness, and transparency is provided, and a disk for recording information and a disk apparatus for recording information using the glass substrate of the disk are provided.

Abstract: A high-density optical disk includes reflective layers respectively formed at both information-recorded surfaces of a first substrate, and semitransparent layers respectively formed at one information-recorded surface of each of second and third substrates. The second and third substrates are respectively bonded at both sides of the first substrate.

Abstract: In a multi-layer optical disk having a first information layer and a second information layer, reproduction of a more excellent quality is made possible. To this end, there is provided a structure wherein the first information layer and the second information layer are laminated to form a sheet of the optical disk. Then, the first information layer has a metal reflecting film with a reflection factor of more than 90% relative to a first reproduction light with a wavelength range of 770 nm.about.830 nm and the second information layer is so structured to have a semi-transparent reflection film wherein a ratio ns.sub.2 /ns.sub.1 between respective real number portions of a refractive index ns.sub.1 against the above mentioned first reproduction light and a refractive index ns.sub.2 relative to a second reproduction light with a wavelength range of 615 nm.about.655 nm is more than 1.05.

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: The invention discloses a method and an apparatus for creating an elementary optical disc master with but a single layer to be applied to a disc substrate to form pits having ideal shapes and without berm buildup. These ideally shaped pits are improvements in the technology of disc mastering, due to the manufacturing and data playback advantages that are inherent in the ideally shaped pits. An optically active lamina consisting of a dye polymer solution of nitrocellulose and a increased dye additive is spin coated directly to a pregrooved polycarbonate substrate to enable the recording of data on the disc by laser means in the form of pits. The pits are created by having a data modulated laser focusing on the optically active lamina which reacts to the irradiation causing a pit to be formed. The resulting pit more often than not possesses a residual raised berm area surrounding the pit, in what is considered to be a less than ideal shape for a pit.

Abstract: A display device is provided comprising one or more masking discs being printed on a surface and a transparent area for viewing printed matter on a substrate disc such as a compact disc. A masking disc or a protective layer includes a bushing extending through a central hole of the compact disc so that each masking disc and substrate disc are rotatably mounted relative to each other. The bushing cooperates with a securing disc to maintain the masking discs and substrate disc together. A magnetic layer secured to the substrate disc comprises means for mounting the display device on a substrate independent of the display device.

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.