Abstract: A high density optical disc having an optical disc protective structure for enabling a high density information recording and retrieval optical disc. The optical disc includes: a first protective film coated by a few tens of microns, on the reading surface of the optical disc, the first protective film having good transmissivity and high hardness against abrasion; and a second protective film coated by a few microns and having a lower surface energy and a minute molecular structure, providing protection against fingerprints on the surface of the first protective film.

Abstract: A method for preparing an optical recording medium of phase change type is provided. This recording medium comprises a substrate, a recording layer, and a lower and an upper dielectric layers provided in direct contact with the recording layer. In this method, a step of an exposure treatment wherein the surface of the lower dielectric layer is exposed to an oxidative atmosphere is conducted after forming the lower dielectric layer on the substrate and before forming the recording layer on the lower dielectric layer. A step of a heat treatment wherein said lower dielectric layer is heat treated may be carried out in addition to the exposure treatment.

Abstract: An optical disc in which a desired exchange reciprocal action is displayed between two sorts of the rare earth-transition metal alloy films to realize optimum recording/reproducing characteristics, and a manufacturing method for the optical disc. To this end, an optical disc 1 includes a first rare earth-transition metal alloy film containing rare earth elements and transition elements and a second rare earth-transition metal alloy film layered on the first rare earth-transition metal alloy film. The second rare earth-transition metal alloy film has a composition different from that of the first rare earth-transition metal alloy film and contains rare earth elements and transition elements. An oxidized area defined between the first rare earth-transition metal alloy film and the second rare earth-transition metal alloy film has an oxygen content not higher than 2.5 atom % and a thickness not larger than 7 nm.

Abstract: A recording medium is for recording information by varying optical characteristic thereof by application of an external energy thereto, and includes a first substance and a second substance. When the external energy is applied to the recording medium, the first and second substances react with each other to form a third substance having a tungsten-bronze crystalline structure, thereby varying the optical characteristic. The third substance absorbs the external energy and varies the reflectivity of the external energy. Thus, the recording medium records information thereon. The recording medium is good in environmental resistance and information retention, because the third substance is stable energetically.

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: 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 improved optical data storage medium and a method of forming and utilizing such a medium. One such optical data storage medium has a substrate having an upper surface including a series of physical deformations which encode data. A reflective film stack carried by the upper surface of the substrate includes both a reflective layer and an overlayer. The reflective layer is formed of a reflective metal and is able to generate a readable data stream from a reflected data reading light. The overlayer is formed of a material which has a higher Young's modulus and/or a higher modulus of compression than the reflective metal and is less reflective of the reading light than is the reflective metal at the same thickness. A protective layer is carried behind the reflective film stack and may serve to protect the reflective film stack against physical damage and environmental attack.

Abstract: Copolycarbonates comprise structural units derived from a bisphenol such as bisphenol A, a spiro(bis)indane bisphenol such as 6,6'-dihdyroxy-3,3,3',3'-tetramethyl-1,1'-spiro(bis)indane and a polyoxyalkylene glycol such as polyethylene glycol. These copolycarbonates have high processability and are expected to have low birefringence. They are useful for the fabrication of optical disks.

Abstract: The invention provides a phase charge type optical recording medium comprising on both sides of a recording layer dielectric layers, each containing zinc sulfide and silicon oxide as main components. The medium comprises on a substrate 2 a first dielectric layer 31, a recording layer 4, a second dielectric layer 32 and a reflective layer 5 made up of a metal. The first dielectric layer 32 comprises a dielectric lamina 1a on a substrate 2 side thereof and a dielectric lamina 1b on a recording layer 4 side thereof. The dielectric lamina 1a has a silicon oxide content of 2 to less than 40 mol %, the dielectric lamina 1b has a silicon oxide content of 40 to 100 mol %, and the second dielectric layer 32 has a silicon oxide content of 2 to 50 mol % and a thickness of 10 to 35 nm. The number of overwritable cycles can be increased.

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 method for recording/reproducing an optical recording medium of phase change type is provided. The method enables a high density recording while increase in the cross erase is suppressed. The method also enables an accurate tracking while increase in the crosstalk is suppressed. The method is adapted for use with an optical recording medium of phase change type comprising a substrate having a thickness of up to 0.8 mm wherein lands and grooves on opposite sides of the land are formed on the surface, and both the lands and the grooves are used as recording tracks, and the medium is overwritten at a recording power Pw (mW) and an erasing power Pe (mW) which meet the relation: (Pw/Pe).times.k.sup.2 .ltoreq.8.5, when the medium has a recording track pitch P (.mu.m), the recording/reproducing optical system has a numerical aperture NA, and the recording/reproducing light has a wavelength .lambda. (.mu.m) which meet the relation: k=(.lambda./NA)/P.gtoreq.1.78.

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: 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: The present invention is a amorphous saturated hydrocarbon thermoplastic substrate having enhanced adhesion properties, wherein the enhanced adhesion properties are obtained by treating the surface of the amorphous saturated hydrocarbon thermoplastic substrate with an excited gas phase technique, such that a critical surface energy of at least 35 dyne/cm is obtained without the use of acids or other corrosive materials which cause equipment degradation.

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: 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: 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: The copper-based sliding material has improved seizure resistance, even if it is free of Pb, and enables thinning of the overlay. The copper alloy provided consists of from 0.1 to 2% of Ag, from 1 to 10% of Sn, and the balance consisting of Cu and unavoidable impurities and, further said Ag and Sn do not essentially form the secondary phases but are in complete or essentially solid-solution state in the Cu matrix.

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 disk with improved performance including a transparent substrate; and a recording layer over the substrate and a reflective layer formed of Au over the recording layer and having its property changed by heat treatment for a sufficient time and at a temperature in a range of about 50.degree.-120.degree. C. so as to significantly improve window margin, reflectivity, jitter.

Abstract: A phthalocyanine dye of specific structure represented by the following general formula (1) or (2): ##STR1## where Y is O or S attached to the phthalocyanine ring, Z is the group of atoms required to complete a carbon or heterocyclic ring together with C, A.sub.1 is a monovalent substituent bulkier than a hydrogen atom, and each of X.sub.1 and X.sub.2 is H or a monovalent substituent or, in the alternative, X.sub.1 and X.sub.2, taken together, form a single bond, ##STR2## where Y and Z.sub.1 have the same meanings as defined for Y and Z in formula (1). A.sub.11 is a monovalent substituent having a branched alkyl group, which is attached to the ring completed by Z.sub.1, and s1 is the number of A.sub.11, is used for the recording layer of an optical recording layer. This phthalocyanine dye is unlikely to attack a substrate material such as PC, can be handled with ease, and has a high solubility in a coating solvent advantageous for film formation, for instance, an alcoholic solvent, e.g.

Abstract: A method for pretreating a solder surface for fluxless soldering is disclosed. The method uses a noble fluorine gas to remove surface oxides from solder surfaces, without the use of external stimulation. A noble fluorine gas is suffused across the solder surface to reduce or eliminate or chemically convert the surface oxides. The process can take place at atmospheric pressure and room temperature. A simple belt driven transport may be used to move the parts past a nozzle which emits the vapor in a system similar to a conventional solder reflow machine.

Abstract: A copper alloy plumbing fixture containing interdispersed lead particles coated non-continuously on a water contact surface to resist the leaching of lead into potable water systems. The leach resistant fixture is prepared by immersing conventional copper alloys in a bismuth nitrate solution, selectively and non-continuously coating the lead dispersoid particles on the water contact surface with bismuth, tin or copper.

Abstract: An optical information recording medium which can be played back by both a playback system for an SD (Super-density Disk) and a playback system for an HDMCD (High Density Multimedia Compact Disk), or by both the playback system for the SD and a playback system for a CD (Compact Disk).

Abstract: An optical disc having an aluminum reflective film is disclosed, wherein an oxide of Al in the stable oxidized state is introduced into the Al reflective film to eliminate changes with lapse of time to improve durability of the optical disc. A method for producing a reflective film on an optical disc is also disclosed, wherein a trace amount of oxygen is introduced into atmosphere in the course of formation of the reflective film.

Abstract: Methods for loading and alignment of liquid crystal polymers in electro-optic and electro-active devices comprise in-situ polymerisation between substrates of monomer material in the presence of a cationic initiator. This allows for the synthesis of liquid crystal polymers containing polyether backbones.

Abstract: A system and method for production of customized compact discs (CD) includes compiling a collection of digital data files from source CDS, receiving customer orders and processing those customer orders by writing customer-selected digital data files onto a CD. Data files are read from the source CDs by an acquisition station and stored in a storage subsystem distributed over a number of data servers. A order input client receives and logs orders from customers. The customer orders are then processed by data servers transferring the cuistomer-selected data files to a writing station. The writing station records the data onto a destination CD. A printing station then prints content description information on the CD and jacket and also prints invoices and shipping labels.

Abstract: An optical disk with improved stability and performance including a transparent substrate; and a recording layer over the substrate and a reflective layer formed of Ag over the recording layer and having its property changed by heat treatment for a time and temperature in a range of about 50.degree.-120.degree. C. so as to significantly improve window margin, reflectivity, jitter, and stability.

Abstract: Various configurations of a directed energy assisted micro embossing machine/station in a vacuum chamber utilized in a continuous manufacturing process and the web structure products made by that process (optical disks, cards, tapes, holographic reflectors, diffusers, binary optical elements, etc.) are disclosed. The configurations can include a single machine roll to roll system for embossing optical features on the surface of a single substrate and applying appropriate metallic, dielectric, semiconductor, polymer and other coatings all in a vacuum chamber.

Abstract: An optical disk with an improved structure of an information pit, and a method of manufacturing the same. The optical disk has projections respectively projecting from bottom surfaces of a plurality of information pits. Also, in the optical disk, laser beams irradiated onto the information pits from an optical pickup to read information recorded on the optical disk are scattered by the projections. Thus, among the laser beams irradiated onto the information pits, the laser beams reflected toward the optical pickup are largely decreased, so that an amplitude and resolution of a reproduced signal are greatly increased, thereby significantly improving reproduction characteristics of the optical disk.

Abstract: A copper-based or silver-based alloy thin film is provided for the highly reflective or semi-reflective layer of optical discs. Alloy additions to silver include gold, palladium, copper, rhodium, ruthenium, osmium, iridium, and platinum. Alloy additions to copper include silver, cadmium, gold, magnesium, aluminum, and nickel. These alloys have moderate to high reflectivity and reasonable corrosion resistance in the ambient environment.

Abstract: A transparent simulation disk for measuring flying height of a magnetic head (i.e., distance between a magnetic head and a magnetic disk such as a hard disk of a computer) in place of a magnetic disk is made of a SiO.sub.2 --R.sub.2 O (where R is Li, Na or K) glass or glass-ceramic having electric resistivity of 10.sup.8 -10.sup.14 .OMEGA.cm and abrasion of 90 or below.

Abstract: Provided is an optical recording medium comprising at least a recording layer, a metal reflective layer, a protective layer and a printing layer laminated on a transparent substrate, wherein the printing layer is obtained by curing a UV-curing ink composition and said ink composition contains a compound which has a solubility parameter falling in the range of 7 to 10 and which takes no part in UV curing and does not react with other components contained therein.

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: A magnetooptical disk includes a thermal diffusion layer to suppress thermal transmission between adjacent information tracks. The information tracks are formed within the magnetooptical disk along respective land portions or groove portions having a difference in grade. During recording and erasing of the magnetooptical disk, the land portions and groove portions may be changed with identical power levels. The thermal diffusion layer diffuses heat generated by irradiation of a laser beam. A protective layer is formed over the thermal diffusion layer and a recording layer which records various bits of information is formed over the protective layer.

Abstract: A substrate for an information recording medium is prepared from a glass substance having a Young's modulus not smaller than 100 GPa and a liquidus temperature not higher than 1350.degree. C.

Abstract: A phase change optical recording medium includes a phase change optical recording layer which transits between two states of the crystalline state and the amorphous state when irradiated with light, and a heat adjustment layer which is formed adjacent to the phase change optical recording layer and abruptly increases or decreases thermal conductivity with increasing temperature upon irradiation of recording light. This phase change optical recording medium can decrease the size of the recording mark and makes high-density recording possible.

Abstract: A dual layer pre-recorded optical disc includes a transparent substrate, a partially reflective layer, a transparent spacer layer, and a highly reflective layer. One pattern of data pits is provided on the substrate, adjacent the partially reflective layer, and another pattern of data pits is provided on the spacer layer, adjacent the highly reflective layer. The transparent spacer layer comprises at least two sublayers. The partially reflective layer may be made of silicon carbide. A substrate-incident beam can be used to read data encoded in either data pit pattern depending on which layer the laser is focused upon. The dual layer disc has twice the data storage capacity of conventional single layer discs.

Abstract: An optical information recording disc of DVD (Digital Video Disc) type having an information recordable layer(s) between a pair of substrates (i.e., sandwich structure) shows an improved mechanical strength and an improved storage stability when the substrate has an exposed area on its outer peripheral edge and the exposed area is placed in contact with a resin layer, or the substrate has an enlarged surface area (preferably it is exposed) on its outer peripheral edge and the enlarged surface area is placed in contact with a resin layer. An apparatus for preparing an optical information recording disc of DVD type having an improved mechanical strength and an improved storage stability is further disclosed.

Abstract: A multilayer optical disk having an information storage layer which can as well as be reproduced by a general purpose reproducing apparatus, for example, a compact disk player, and from which information can be read from other information storage layers by using an exclusive reproducing apparatus. The multilayer disk has a first substrate on which is formed a first information storage layer which is relatively highly reflective with respect to a light beam having a wavelength of 770-830 nm; and a second substrate on which is formed a second information layer which is relatively transparent with respect to a light beam having a first substrate on which is formed a wavelength of 770 mn to 830 nm but which is sufficiently reflective with respect to a light beam having a wavelength of 615-655 nm.

Abstract: A method for forming a protective barrier layer between the active dye layer and the disc substrate during production of an optical memory disc is provided wherein a pre-treatment/pre-coat solution is applied to the disc substrate. This pre-treatment/pre-coat solution includes a surface modifier having an index of refraction approximately equal to that of the disc substrate. Surface modifiers utilized in this pre-treatment/pre-coat solution include poly vinyl alcohol, poly alpha methyl styrene, cellulose acetate, poly vinyl butyral and nitrocellulose.

Abstract: An optical information recording medium, which is not deteriorated after repeated reading out and writing in operations, is provided by forming a glass thin film, which varies the intensity or the intensity distribution of light, on a substrate, and providing a recording film, a protective film, and a reflecting film thereon.

Abstract: The present invention provides a magneto-optical medium and a reproducing device for the medium. In the magneto-optical medium, a mark in a magneto-optical recording area is so formed as to correspond to one of "1" and "0" of data to be recorded, and in a pre-formatted recording area, a pit in formed so that an edge of said pit corresponds to one of "1" and "0" of the data to be recorded. Therefore, when the magneto-optical recording area and the pre-formatted recording area have substantially the same linear recording density, only one pit exists in the spot area of a reproducing beam. As a result, an excellent characteristics can be obtained due to a superresolution effect.

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: 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: 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 phase change optical recording medium having an increased number of overwritable operations is provided. In this medium, the recording layer is disposed between a first dielectric layer and a second dielectric layer which contain zinc sulfide and silicon oxide as their main components; and difference between light absorption coefficient (Ac) of the recording layer in the region other than record marks (in crystalline state) and the light absorption coefficient (Aa) of the recording layer in the record marks (in noncrystalline state) is small, or Ac>Aa. More illustratively, the first dielectric layer is disposed underneath the recording layer and the second dielectric layer is disposed over the recording layer; and the conditions: Ac/Aa.gtoreq.0.9 and/or light transmittance .gtoreq.1% is satisfied.

Abstract: In the optical recording medium including a substrate having pregrooves, and a metal recording layer, a buffering layer, a reflecting layer and a protecting layer which are sequentially stacked on the substrate, an angle (.theta.) of the slanted side of the pregrooves is 30.about.90.degree. and the buffering layer has 10.about.50,00O Pa.S melt-viscosity at 140.degree. C. Therefore, the optical recording medium can be compatible with a CD and playable by a DVDP, and manufactured at low costs without using a dye, while providing a high reflectivity at longer wavelength than 600 nm.

Abstract: The invention pertains to an optical recording medium comprising a homeotropically oriented liquid crystalline polymer film having a T.sub.g between 75-100.degree. C. and a T.sub.c between 110-140.degree. C. and comprising at least one dichroic dye. This homeotropic orientation along with the presence of dichroic dye makes it possible to employ a different technique for writing out and reading data. For, in this case contrast is obtained by the dichroic dye contained in the film being aligned in the same direction as the mesogenic groups of the liquid crystalline polymer. In a virgin film the mesogenic groups, and hence the dichroic dye molecules, are oriented perpendicular to the film's surface, and there is only low absorption of the incident light by these molecules. By local heating or irradiation of the film (e.g., with a laser) the homeotropic orientation is converted to an isotropic one.

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.