Abstract: An optical disk which operates which two of more different wavelengths, comprising a disk substrate on which tracks are formed at a track pitch of not more than 0.5 &mgr;m corresponding to light with a short wavelength, a super-resolution film whose transmittance changes due to irradiation of light, and a recording layer, wherein the transmittance of the super-resolution film changes due to the irradiation of light with a long wavelength. In this optical disk, information recorded by light with a short wavelength can be reproduced by light with a long wavelength.

Abstract: An optical memory system includes memory cells which utilize synthetic DNA as a component of the information storage mechanism. In the preferred embodiment, memory cells contain one or more chromophoric memory units attached to a support substrate. Each chromophoric memory unit comprises a donor, an acceptor and, at some time during its existence, an active quencher associated with the donor and/or the acceptor. The donor and the acceptor permit non-radiative energy transfer, preferably by Förster energy transfer. To write to the memory cell, the quencher is rendered inactive, preferably by illumination with ultraviolet light. To read, the chromophoric memory units in a read portal are illuminated, and the read illumination is detected. In the preferred embodiment, multiple chromophoric memory units having resolvable read properties are contained within a single read portal. In this way, a multibit word of data may be read from a single diffraction limited read portal.

Abstract: An optical recording medium comprises a first information recording surface; a first reflecting layer formed on the first information recording surface; a second information recording surface; and a second reflecting layer formed on the second information recording surface. In particular, the first reflecting layer contains a titan oxide as a main component.

Abstract: In an optical recording medium having a super-resolution layer structure using near-field light, comprising a readout layer 3 for forming a light scattering region 9 in the center portion of a laser spot, and a recording layer 5 for receiving near-field light 10 generated from the light scattering region 9 of the readout layer 3, scattering bodies 61 for increasing the generated near-field light are provided while enhancing a scattering effect of the near-field light 10 applied to a mark 51 of the recording layer 5.

Abstract: An optical storage element capable of writing and/or erasing information by irradiation with light, which element comprises a first unit composed of a first photo-induced phase-transition substance that gets stable in a first state, and a second unit composed of a second photo-induced phase transition substance that gets stable in a second state, the first and second units being arrayed in a superlattice-like form.

Abstract: A two-color hologram recording/reproducing apparatus is capable of directing interferable signal light and reference light into a hologram recording medium to record an information signal carried by the signal light. The hologram recording medium is sensitive to a first light at a first wavelength in an ultraviolet or short-wavelength visible light band to develop light induced absorption. The apparatus includes a light source for irradiating the hologram recording medium with the first light, a laser light source for irradiating the hologram recording medium with signal light and reference light at a second wavelength longer than the first wavelength after the first light is irradiated, and a gate light source for directing gate light at a third wavelength into the hologram recording medium.

Abstract: A high-density recordable optical recording disk with a cyanine dye mixture as a recording layer. The cyanine dye mixture at least comprises cyanine dye I and cyanine dye II.

Abstract: The present invention discloses optical recording elements having optical recording layers containing tetra dyes. The dyes have metallized azo dianionic dye with cationic dye counterions. The recording layer has a thickness from 225 to 300 nm.

Abstract: A method of manufacturing an optical disk comprises: bonding a resin stamper having, on a principal plane, asperity pits on which a thin film is formed and a second substrate having a thickness of 0.3 mm or less with radiation cured resin such that the asperity pits face to the second substrate; peeling off the resin stamper after curing the radiation cured resin to form asperity pits on the second substrate; forming a metal film on the asperity pits on the second substrate to attain an information recording layer on the second substrate; and bonding a first substrate having an information recording layer and the second substrate having the formed information recording layer such that the both information recording layers face each other.

Abstract: A novel optical recording medium having at least a recording layer and a reflective layer on a substrate is herein disclosed, wherein at least one dipyrromethene metal chelate compound represented by formula (1) is contained in the recording layer: wherein R1 and R9 are each independently an alkenyl group, an aryl group or a heteroaryl group; R2 to R8 are each independently a hydrogen atom, a halogen atom, or a substituted or unsubstituted alkyl, alkoxy, alkenyl, acyl, alkoxycarbonyl, aralkyl, aryl or heteroaryl group having 20 or less carbon atoms; and M is a transition metal.

Abstract: A phase change optical disk having excellent corrosion resistance, recording signal properties and overwrite cyclability, which contains a first dielectric layer, a recording layer, a second dielectric layer, a reflection layer and a protection layer, characterized in that the reflection layer comprises a first reflection layer made of a metal or an alloy thereof having an electronegativity ranging from 1.9 to 3.0 and a second reflection layer made of Cu, Ag or an alloy thereof, said first reflection layer being in closed contact with the second dielectric layer, and the second reflection layer, with the first reflection layer and the protection layer.

Abstract: A rewritable phase change type optical recording medium having excellent in storage durability such as archival property and overwrite shelf property and is less likely to have increased jitters, lower contrast and bursting due to deterioration by repeated overwriting is disclosed. The optical recording medium comprises a first dielectric layer, a first boundary layer and a recording layer, in tis order, wherein the first boundary layer is in contact with the recording layer. The information in the optical recording medium can be recorded, erased and reproduced by irradiating the recording layer with light. The recording and erasure of information are affected by reversible phase change between amorphous phase and crystalline phase of the recording layer.

Abstract: A magneto-optical recording medium includes at least a first magnetic layer, a second magnetic layer and a third magnetic layer which are layered in this order, the first magnetic layer being formed of a perpendicularly magnetized film having a relatively small wall coercivity and a relatively large wall mobility compared with the third magnetic layer in the vicinity of a predetermined temperature, and the magneto-optical recording medium satisfies conditions Tc2<Tcomp1<Tc1 and Tc2<Tcomp1<Tc3 where Tcomp1 is a compensation temperature of the first magnetic layer, Tc1, Tc2 and Tc3 are Curie temperatures of the first, second and third magnetic layers, respectively.

Abstract: An optical recording medium comprises a recording layer containing, as a photoresponsive material, metal chalcogenide nanoparticles, wherein the metal chalcogenide nanoparticles have an average particle size of 1 to 20 nm and have a surface modified with an adsorbable compound.

Abstract: A dye record disc has a disc shape substrate having a track-forming surface divided into a read-only area and a recordable area. A reproducing track is formed on the track-forming surface in the read-only area, and has a plurality of pits, each of the pits comprising a dye material, and having a shape corresponding to the reproducing information. A recording/reproducing track is formed on the track-forming surface in the recordable area, and extends continuously, the recording/reproducing track comprising the same dye material as each of the pits.

Abstract: A phase change optical disk having a reflectance relation of Rc<Ra and is adapted such that high recording characteristic can be obtained starting at a first recording time even when a recording operation is carried out without conducting an initialization process. For this purpose, a multiple reflection layer (2), a first dielectric layer (3), a recording layer (4), a second dielectric layer (5), a reflecting layer (6) and an UV curable resin layer (7) are provided on a substrate (1). The recording layer (4) is deposited at a temperature of the substrate during the deposition of the recording layer set to a temperature which makes the recording layer into a stable amorphous conditions and which is lower than a crystallizing temperature of the recording layer. Thus, the recording layer (4) is deposited into a stable amorphous state.

Abstract: In an optical disk which includes a recording film having a laminated construction, and which records information by changing optical characteristics of the recording film by applying a laser beam, there are laminatedly formed a WO3 film 2 as a second layer, the WO3 requiring energy by about 470 kJ when it dissociates 1 mol of oxygen molecules, an Sn—43 atomic % Bi film 3 which includes Sn as a first layer, the Sn generating energy by about 610 kJ when it bonds with 1 mol of oxygen molecules and having a melting point of about 139° C., and a resin film 4 in this order on a guide groove 1c forming surface 1b of a substrate 1. When a recording laser beam is applied, a part of Sn—43 atomic % Bi film 3 is turned into a liquid phase, both of the films 2 and 3 react, and the optical characteristics of the recording film 10 vary so that information is recorded. As a result, the retention characteristic of the recorded data is secured, and the reactivity of the recording film is enhanced.

Abstract: Cards which contain any one of the following thermoplastic resin compositions I to III in its material can be used as magnetic cards, IC cards, etc. since they are excellent in heat resistance, processability and embossability: a composition consisting of ingredients (A) and (B); a composition consisting of ingredients (A), (B) and (D); and a composition consisting of 100 parts by weight of one or more selected from the following ingredients (A), (B) and (D) and 2 to 25 parts by weight of the following ingredient (C), wherein ingredient (A) is a polyester composed of dicarboxylic acid components with terephthalic acid component as a main dicarboxylic acid component and ethylene glycol component (I) and 1,4-cyclohexanedimethanol component (II) as main glycol components, wherein the molar ratio (I)/(II) of ethylene glycol component (I) to 1,4-cyclohexanedimethanol component (II) is 1 or more; ingredient (B) is an aromatic polycarbonate; ingredient (C) is an inorganic sheet-like filler of 0.

Abstract: An optical recording medium of phase change type wherein favorable recording/reproducing properties are realized in high density recording, in particular, when the minimum mark length is up to 0.6 &mgr;m and the track pitch is up to 0.7 &mgr;m is provided. An optical recording method wherein high transfer rate is realized in the use of such high density recording medium is also provided. The optical recording medium has a recording layer having a thickness dr of 10 to 18 nm, and the first dielectric layer comprises one or more unit dielectric layers and the number of the unit dielectric layers is m (m: an integer of 1 or more).

Abstract: An amorphous alloy of light rare earth-transition metal and semi-metal, having a perpendicular magnetic anisotropy without decrease of magnetic moment of light rare earth metal in a short wavelength region, a magneto-optical recording layer made of the amorphous alloy, and a magneto-optical disk adopting the magneto-optical recording layer are provided. According to the magneto-optical recording layer, the semi-metal is added to the amorphous alloy of the light rare earth-transition metal to induce p-d electron orbit coupling between the transition metal and the added semi-metal of the amorphous alloy, thereby decreasing the demagnetizing energy of the amorphous alloy according to the decrease of a magnetic moment of the transition metal, without any effect on the magnetic moment of the light rare earth metal.

Abstract: Composition and use of polymers in appropriate solvent(s) with or without addition of selected dye combinations are proposed for developing a thin-layer coating on the transparent layer of optical storage media such as audio and video CDs, laser discs (LD) and DVDs for improvement of the sound and/or video quality during either recording and/or playback of the encoded digital information. The invention can also be incorporated in manufacture of recordable (CD-R) and re-writeable CD (CD-RW) media. In that case, the proposed composition is applied on the polycarbonate transparent surface of optical storage media at the final stages of recordable media manufacturing.

Abstract: An optical disk includes at least two information recording layers on one side of the disk and at least the first information recording layer from the light incident side is of an erasable type formed with a material such as bismuth-substituted magnetic garnet or cobalt ferrite which has an extinction coefficient, a coefficient of an imaginary part of a complex index of refraction, being not more than 1.0, but not less than 0.5, and gives a large magneto-optic effect and a small light absorptivity.

Abstract: A disc-shaped recording medium having transcription characteristics for fine signals simultaneously with resonance characteristics and stiffness which are characteristics contrary to the transcription characteristics. At least a recording layer and a light transmitting layer are sequentially formed on a substrate and light is illuminated from a light transmitting layer side to record and/or reproduce information signals. The substrate includes a core layer formed of a resin composition comprised of a mixture of two or more resin sorts. The resin composition has tan&dgr;, as an index indicating the internal loss, equal to not less than 0.015 as a system in its entirety. The resin composition constituting the core layer is a compounded resin of the incompatible system and is of an islands-sea structure.

Abstract: A recording medium includes a first substance and a second substance at least in which the first and second substances undergo an oxidation-reduction reaction when an external energy is applied, thereby recording information by varying the optical characteristics. In the recording medium, the reaction of the first and second substances is suppressed, reaction which degrades the recording characteristics other than the case where the recording medium is subjected to recording. In an optical disk 100 (i.e., the recording medium), a WO3 film 2 (i.e., a second substance), a C film 3 (i.e., a third substance) and an Sn-10 atomic % Sr film 4 (i.e., a first substance) are formed successively on a substrate 1. When the recording medium is irradiated with a recording laser beam as an external energy, the WO3 forming the film 2 is reduced to WO2.

Abstract: An optical recording medium having a structure including that a recording layer containing organic coloring matter and a reflecting layer that are sequentially formed on a light-transmissive substrate thereof so that an information signal is recorded/reproduced when the optical recording medium is irradiated with a laser beam made incident on the light-transmissive substrate, the optical recording medium incorporating: a light absorbing layer which is formed more adjacent to an incident point of the laser beam as compared with the reflecting layer, through which the laser beam passes and which absorbs light in an absorption wavelength region for the recording layer. Photo-deterioration of the recording layer composed of organic coloring matter occurs owing to a portion of natural light which has the wavelength which exists in the absorbing wavelength region for the organic coloring matter.

Abstract: Disclosed is an optical recording layer in which the microaperture for reproducing optical near-field light is controllable so as to read out the optical near-field signals with stability by keeping the signal-reproducing head at a height safe from crashing with the recording medium even when the recording marks are smaller than 100 nm. The optical recording medium is a layered body comprising: (a) a transparent substrate; (b) a first protective layer formed on the substrate; (c) an optically or thermally active layer, which is capable of reversibly generating a micro-aperture by application of light or heat, formed on the first protective layer; (d) a second protective layer, which is under a compressive stress of 200 MPa to 1 GPa, formed on the active layer; (e) an optical recording layer formed on the second protective layer; and (f) a third protective layer formed on the optical recording layer.

Abstract: An information recording medium which is composed of a substrate and a recording layer formed thereon to record information by means of the change in atomic arrangement induced by irradiation with light, said recording layer having at least one interface layer laminated at its interface. It is superior in recording-reproducing-rewriting characteristics and archival life.

Abstract: A phase change optical recording medium which enables optimum direct overwrite even under high speed high density conditions without degrading repetition durability or storage stability of recorded signals. To this end, the phase change optical recording medium has a recording layer formed at least of a phase change material and is recorded and/or reproduced with a laser light beam having a wavelength ranging between 380 nm and 420 nm. A ratio Ac/Aa, where Ac is the absorption rate of said recording layer in a crystalline state and Aa is the absorption rate of said recording layer in an amorphous state, is not less than 0.9, and a crystallization promoting layer promoting the crystallization of the phase change material is contacted with at least one surface of the recording layer.

Abstract: The invention is a magnetic recording medium which is effectively protected against forgery by the alteration of recorded data, and a method for carrying out writing and reading on this magnetic recording medium. The magnetic recording medium of the invention comprises a recording material composed of a crystalline alloy containing Fe and Al . In the recoding material, the total amount of Fe and Al is at least 90 at % and the atomic ratio Al/(Fe+Al) ranges from 0.30 to 0.45. The recording material changes from a disordered phase to an ordered phase by heating. The recording material has a saturation magnetization of at least 45 emu/g prior to heating and lowers its saturation magnetization by at least 35 emu/g upon heating. Dark regions are observable in a bright-field image of the recording material by transmission electron microscopy, the dark regions accounting for 15-60% of the recording material in areal ratio and having a maximum breadth of 10-200 nm.

Abstract: An optical memory device and a method for manufacturing thereof. An optical memory device has at least one data layer formed on a substrate. An upper surface of the substrate is formed with a pattern comprising a plurality of regions which are capable of obtaining, when covered by a recording medium, desired optical properties different from those of the substrate. The patterned surface of the substrate is coated with the recording medium. The recording medium is removed from the patterned surface after the recording regions have obtained the desired optical properties.

Abstract: An optical recording medium incorporating a supporting body; a recording portion which is formed on either main surface of the supporting body and on which a signal is recorded; and a light permeable layer formed on the recording portion, wherein light is applied from a position adjacent to the light permeable layer to record/reproduce a signal, and carboxylic acid amine salt expressed by general formula (1) and/or general formula (2) is held on the surface which is irradiated with light where n is an integer from 1 to 3, each of R1 and R2 is hydrogen or a hydrocarbon group, R3 is a hydrocarbon group and Rf is a perfluoroalkyl group having three or more carbon atoms, where at least either of R1 and R2 is perfluoroalkyl group having three or more carbon atoms, at least any one of R1, R2, R3, R4 and R5 is hydrocarbon group having 12 or more carbon atoms and the rest of them are hydrogen or hydrocarbon group.

Abstract: A magneto-optical recording medium includes a reproducing layer, a recording layer and an intermediate layer provided between the reproducing layer and the recording layer. The reproducing layer is an in-plane magnetization film at least at room temperature, and becomes a perpendicular magnetization film at a temperature between room temperature and the Curie temperature thereof. The recording layer is a perpendicular magnetization film in a temperature range from room temperature to the Curie temperature thereof. The intermediate layer has a larger in-plane magnetic anisotropy at room temperature than the in-plane magnetic anisotropy of the reproducing layer.

Abstract: An optical recording layer of an optical recording medium comprises a dye material represented by the formula (I), wherein R1 is a hydrogen atom, a methyl group, or an ethyl group, R2 and R3 each is, independent from each other, a substituted or unsubstituted C1 to C12 alkyl group, A⊖ is an anion selected from the group consisting of halogen atoms, ClO4⊖, BF4⊖, PF6⊖, SbF6⊖, CF3SO2⊖, C2F5SO3⊖, CF3COO⊖, and CH3C6H4SO3⊖, X is hydrogen, alkyl, alkoxy, halogen, nitro, or fused benzene, Y is hydrogen, alkoxy, halogen, alkyl, aryl, alkoxycarbonyl, aryloxycarbonyl, alkylamine, arylamine, alkylamide, arylamide, alkylsulfonyl, aryl sulfonyl, alkoxysulfonyl, aryloxysulfonyl, nitro, or cyano groups.

Abstract: In an apparatus for fabricating a carbon coating, an object such as a magnetic recording medium is disposed on a side of an electrode connected to a high-frequency power supply. Ultrasonic vibrations are supplied to the object. Discharge is generated between the electrode connected to the high-frequency power supply and a grounded electrode to fabricate a carbon coating on the surface of the object. Also, an electrode interval is set to 6 mm or less, pressure between the electrodes is set to 15 Torr to 100 Torr, whereby high-density plasma is generated to form an ion sheath on an anode side. Therefore, a coating is fabricated on the surface of the object by bombardment of ions.

Abstract: In a phase change optical recording medium, by determining heat conductivity relatively higher in one of interference layers on and under the recording layer, heat absorbed into the recording layer can be released moderately through an interference layer. Thereby, cross erasure caused by heating of adjacent tracks can be prevented, and at the same time, excessive heat radiation is prevented from a part of the recording layer nearer to the substrate to thereby maintain appropriate heat in the recording layer. As a result, cross-erasure is prevented, and data can be rewritten with the supply of typical recording/erasure power.

Abstract: An optical information recording medium having a multilayer structure comprising at least a lower protective layer, a phase-change type optical recording layer, an upper protective layer and a reflective layer, on a substrate, wherein the phase-change type optical recording layer has a composition of Gef(SbdTe1−d)1−f, where 0.65≦d≦0.85, and 0.01≦f≦0.20, whereby overwrite recording is carried out by modulation of light intensity of at least strong and weak two levels, so that a crystalline state is an unrecorded state, and an amorphous state is a recorded state.

Abstract: The 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: An optical information recording medium having a recording layer comprising a dye layer containing a trimethine-based cyanine dye having nitro group attached to a benzene ring or to a naphthalene ring, both being bonded to indole ring, is capable of minimizing the second peak in relative to the main peak shown in FIG. 1, thus enabling the spectrum consisting of a main peak and a second peak to become sharp. The recording layer is capable of performing the recording and reading with a laser beam having a wavelength falling within a range of 620 nm to 690 nm.

Abstract: A re-usable information recording medium provided with a sensitive layer which comprises a plurality of particles having a magnetically responsive position, and a retaining material embedding the particles and having a temperature dependent viscosity, the particles and the retaining material exhibiting light absorption spectra which are different one from the other.

Abstract: An information recording medium comprising a substrate having a recording surface provided with emboss pits or guiding grooves, a reflective film formed on the recording surface of the substrate, and a first protective film formed on the reflective film. This information recording medium is featured in that both sides of the information recording medium are constituted by a first surface provided with the protective film and by a second surface formed opposite to the first surface, and that an irradiated light beam is irradiated through the first surface, a recorded information being reproduced based on changes in light intensity of the reflected light beam.

Abstract: A thin-film optical recording medium and compatible materials is disclosed. When the transparent layer and the reflecting layer of the present invention are exposed to a light beam, the two layers react to form a semi-transparent reflective alloy/compound area. The presence of such area (1) decreases the effective optical thickness of the transparent layer and/or (2) forms a region of changed optical n & k and/or (3) changes the optical polarization angle. At least one of the above three effects produces an optical contrast before and after the recording from which the signal modulation required for reading the optical media can be derived. The present invention allows high-density, high-resolution, high-speed recording of data that is highly compatible with the full visible-light spectrum.

Abstract: The present invention provides a label for optical disks which comprises a base sheet having a coefficient of linear expansion of 1.0×10−5 to 12.0×10−5 and a thermal shrinkage ratio of 3 or below percent, a display formed on at least one surface of the base sheet, and an adhesive layer formed on a surface of the base sheet or the display. The label for optical disks can be applied on the surface of the optical disk with displays such as various printings and pholograms, and can provides an optical disk having beauty and fineness in aesthetic.

Abstract: A luminous disk is disclosed in this invention. The luminous disk comprises a disk lamination and a light emitting lamination. The disk lamination at least comprises a substrate and a metallic reflecting layer. The light emitting lamination at least comprises an electroluminescence section having a first side plane and a second side plane, and a biasing section for applying an external electrical signal onto the first and the second side planes so as to make the electroluminescence section luminesce. Basing on the above structure, a new disk having a redoubled effect is available.

Abstract: An information recording medium includes a substrate, a first protective layer formed on the substrate, a recording layer formed on the first protective layer, and a second protective layer formed on the recording layer. The first protective layer has a thickness in a range from 65 nm to 130 nm. The second protective layer has a thickness in a range from 15 nm to 45 nm. The recording layer has a thickness in a range from 15 nm to 35 nm and is composed of a phase-change alloy with the composition in terms of atomic percentage being represented by the formula AgaInbSbcTed where 0<a<6, 3≦b≦15, 50≦c≦65, 20≦d≦35, a+b+c+d=100. The information recording medium is configured to provide capabilities of reading, writing and overwriting of information at linear rotation rates ranging from 1.2 m/s to 11.2 m/s.

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, beryllium and platinum. Alloy additions to copper include silver, cadmium, gold, magnesium, aluminum, beryllium, zirconium, and nickel. These alloys have moderate to high reflectivity and reasonable corrosion resistance in the ambient environment.

Abstract: In an optical recording medium in which at least a heat diffusion layer, a first dielectric layer, an information recording layer and a second dielectric layer are formed in this order on a substrate and signals are recorded and/or reproduced by the light illuminated from the side of the second dielectric layer, it is desirable to optimize recording and/or reproducing characteristics. With this in view, an under layer 3 for optimizing surface properties of a heat diffusion layer 4 is formed between a disc substrate 2 and the heat diffusion layer 4.

Abstract: In the optical recording medium including a substrate having pregrooves, and a metal recording thin film, a buffering layer and a reflecting layer which are stacked in sequence on the substrate, the buffering layer is formed of one or more dyes having a refractive index (n) of 1.4 or more and an absorption coefficient (k) of 1.6 or less at a wavelength of 650 nm, and a refractive index (n) of 1.8 or more and an absorption coefficient (k) of 0.001 or more at a wavelength of 780 nm. Therefore, the optical recording medium is reproducible by a CD player and a DVD player. Also, due to a metal recording thin film layer formed on a substrate, the amplitude of a recording signal is increased and the optical reliability is also improved. Also, because of a thin buffering layer, the manufacturing costs can be reduced. Also, by adding a material whose weight is rapidly lost during decomposition to the buffering layer, the recording sensitivity and the optical reliability can be much improved.

Abstract: This invention relates to a rewritable optical information recording medium of the phase-change type, which is made of a Te—Ge—Sb—B quaternary alloy. The optical contrast of the recording medium according to the present invention is enhanced over 35% in the visible wavelength range of 350 nm to 800 nm. Hence, the CNR of an optical disk with the recording medium of the present invention is increased, and the recording medium is suitable for optical information record operated in shorter visible wavelength. In addition, since the crystallization of the recording medium according to the present invention is single-phase, the performance of the repeated recording and erasing is enhanced.

Abstract: Compositions of bacteriorhodopsin variants with increased memory time and their use for reversible optical information recording are disclosed. The compositions are characterized in that the configuration of the retinal of the photoproduct is different from the configuration of the retinal of the initial state and other than 13-cis; the pH value of the composition lies between 3 and 11; the water content of the composition lies between 1 and 30% by weight with respect to the total weight of the composition; and additives for modulating the proton mobility are present in a concentration between 1 and 80% by weight of the mass of purple membrane composition used, and if required matrix materials in a concentration of up to 10% by weight with respect to the total weight of the composition are present. These compositions may be used in reversible information recording systems.

Abstract: Metallized azo ether dyes having an azo group linking a substituted 3-hydroxypyridine nucleus to a phenyl nucleus are disclosed. The phenyl nucleus has an ether substituent ortho to the azo group. The phenyl nucleus is free of strong electron withdrawing substituents. The dyes are useful in optical recording elements.