Abstract: A heat-sensitive recording material for laser recording is provided including a support having thereon a heat-sensitive layer including at least a first substantially colorless coloring component, a second substantially colorless coloring component which reacts with the first substantially colorless coloring component to develop a color, and an infrared-absorbing dye.

Abstract: A cyanine compound of the following formula: ##STR1## wherein T.sup.1 and T.sup.2 each independently represents an atomic group which is necessary for forming a condensed benzene ring; L.sup.3 represents a methine group or a trivalent connecting group formed by conjugated double bonding of 3, 5 or 7 methine groups; R.sup.21, R.sup.22, R.sup.23 and R.sup.24 each independently represents an alkyl group having 1 to 12 carbon atoms or a phenyl group both of which may or may not be substituted; Y is an anion and q is a number which is necessary for neutralizing a positive charge; provided that at least one of R.sup.21, R.sup.22, R.sup.23 and R.sup.24 is an alkyl group having 3 or more carbon atoms and which may or may not be substituted when L.sup.3 consists of 1, 3 or 5 methine groups.The cyanine compound can be used as a coloring material, a sensitizing dye for photographic use, a recording dye for use in optical information recording media, a staining agent, a pharmaceutical agent, and the like.

Abstract: An optical information recording medium for carrying out recording, readout or erasing by laser beam which comprises a support having carried thereon a recording layer containing dye(s) represented by the general formula (I): ##STR1## wherein R.sup.1 and R.sup.2 independently represent substituted or unsubstituted alkyl groups, substituted or unsubstituted alkenyl groups, or substituted or unsubstituted aryl groups, L represents a substituted or unsubstituted methine group, or a linking group formed by linkage of 3, 5 or 7 substituted or unsubstituted menthine groups through conjugated double bonds, Z represents an atomic group for completing an aromatic ring optionally having substituent(s), and X.sup.- represents a monovalent or divalent anion for neutralization of electron charge of the cationic part.

Abstract: A method of optically recording information on an information recording medium comprising a disc-shaped substrate having a pregroove comprising a groove having a depth of 800 to 2,000 angstroms and a half width of 0.2 to 0.7 .mu.m thereon, a recording layer comprising a dye for optically recording information by means of a laser beam which is provided on the substrate, and a reflecting layer of a metal which is provided on the recording layer is disclosed. The recording method is carried out by irradiating a bottom part of the pregroove having the recording layer thereon with a laser beam from the substrate side under rotation of the recording medium. Further, an information recorded medium which is recorded with information by the above method is also disclosed.

Abstract: Disclosed is an information storage medium having an air-sandwich structure which comprises two disc-shaped substrates joined together through a ring-shaped inner spacer and a ring-shaped outer spacer. These spacers are made of the same kind of resin as those forming the disc substrates and the resin of the spacers has a viscosity-average molecular weight larger than that of the resin of the substrates. Also disclosed is a process for producing the information storage medium by joining the spacers to the disc substrates by means of ultrasonic welding.

Abstract: An optical information recording medium for carrying out recording, readout or erasing with layer beams, which comprises a support having carried thereon at least one compound represented by the general formula (I): ##STR1## wherein R.sup.1 and R.sup.2 independently represent substituted or unsubstituted alkyl groups, or substituted or unsubstituted aryl groups, Z represents an atomic group for forming a substituted or unsubstituted aromatic ring, and L represents a linking group for forming a carbocyanine.The present optical information recording media have an excellent recording performance and stability, and dyes used therein have no explosive property and thus can safely and readily be prepared.

Abstract: The present invention relates to an optical information recording medium which comprises a support having provided thereon recording layer(s) on which information can be recorded and/or read out with a laser beam, wherein the recording layer contains at least one of the compounds represented by the following formula (I): ##EQU1## wherein .phi. and .PSI. each represents a heterocyclic residue having nitrogen atom(s), and L represents an optionally substituted methine group, or an optionally substituted trimethine, pentamethine, heptamethine or nonamethine group each formed by linkage through conjugated double bonds, provided that L and at least one of .phi. and .PSI. combine to form a ring; and X.sup.1 .theta. represents a 1-valent negative ion and l represents 1, 2 or 3, provided that X.sup.1 .theta. may bind to .phi., L or .PSI. as a substituent is provided by the invention.

Abstract: An optical recording medium comprising at least one recording layer on a substrate and a protective layer overlying the recording layer, the protective layer comprising a UV cured resin composition containing a urethane acrylate, N-vinylpyrolidone, a trifunctional or higher functional acrylate, and a photoinitiator.

Abstract: The present invention is directed to an optical information recording medium for carrying out recording, readout and erasing with laser beams which comprises a support having carried thereon at least one of the compounds represented by the following general formulae (I), (II), (III) and (IV): ##STR1## wherein X and X' each represents an atomic group necessary for forming a carbon ring or an atomic group necessary for forming a specific heterocyclic ring; L.sup.1 mainly represents a methine group, or a group formed by linking 3 or 5 methine groups in turn to form conjugated double bonds; and Q and Q' each represents an atomic group whereby a conjugated double bond chain is completed; ##STR2## wherein L.sup.1 and Q are as defined in general formula (I); Z represents an atomic group necessary for forming a carbon ring or heterocyclic ring; R.sup.1 to R.sup.3 and E represent various substituents; and M represents an ion, etc.

Abstract: A process for the preparation of an information recording medium comprising a substrate and a recording layer for writing and/or reading information by means of a laser beam which is provided on the substrate, wherein said recording layer is formed on the substrate by coating a solution which contains a dye in a solvent containing diacetone alcohol over the substrate to form a dye-coated layer, and drying the coated layer is disclosed. Also disclosed is a process for the preparation of an information recording medium comprising a substrate, an intermediate layer and a recording layer, superposed in order.

Abstract: A novel information recording medium comprising a substrate and a recording layer for writing and/or reading information by means of a laser beam which is provided on the substrate is disclosed. The recording layer contains a dye having at least one chromophore selected from the group consisting of an amidinium ion chromophore, a carboxyl ion chromophore and a dipolar amide chromophore, and an organic solvent-soluble silver salt. Alternatively, the recording layer contains said chromophore and this recording layer is arranged in contact with a layer of an organic solvent-soluble silver salt.

Abstract: The present invention relates to an optical information recording medium for carrying out recording, reproduction and erasing with laser beams which comprises a support having carried thereon at least one methine dye which consists of an azulene nucleus, at least one of 10 carbon atoms of which is replaced by chalcogen atom(s) and/or nitrogen atom(s), and further whose 7-membered ring part is substituted with a methine bond having at the terminal an auxochrome which forms a conjugated resonance chromophore together with a 10 .pi. electron system of the nucleus.Optical information recording media of the invention have adequate recording characteristics having high C/N, and have high stabilities against long-term preservation or against long-time reading.

Abstract: Disclosed is an optical disk used as a recording medium of the type described as an air-sandwiched structure including two disk-shaped substrates, which are secured to each other by way of an inner and outer plastic spacer. Together, the two substrates and the inner and outer spacer define a closed inner space, and at least one inner surface of one of the two substrates is provided with a light-sensitive recording layer. Typically, such a recording layer is sensitive to high energy light such as that from a laser beam. Each of the disk-shaped substrates includes a central hole of equal size and shape, wherein the inner spacer is ring-shaped and is positioned with its central opening coaxial with the holes in the substrates.

Abstract: A method of recording information comprising the steps of: irradiating a light-absorbing material (which is arranged in contact with a polymer blend which changes in its phase condition between a homogeneous state and a phase-separated state in response to change of its temperature across its cloud point) with a laser beam for causing the light-absorbing material to absorb energy of the beam and generate a heat, whereby elevating the temperature of the polymer blend near the light-absorbing material to a temperature of above the cloud point to change the phase condition of the polymer blend into a state which is different from the original state before the elevation of the temperature; and rapidly cooling the polymer blend to fix the polymer blend in its changed phase condition. An information recording medium preferably employed for the method is also disclosed.

Abstract: A process for preparing an information recording medium in the form of an optical disc comprising a substrate and a recording layer. The recording layer is formed on the substrate by coating a dye solution which comprises a dye dissolved in a solvent of a fluorine-containing compound over the substrate, and drying thus coated layer.

Abstract: An optical information recording medium of two disc substrates, which are adhered directly or through a convex portion formed on at least one of the substrates or a spacer provided between the substrates by an adhesive layer, and a recording layer which is capable of recording and/or reading information by laser beam and which is provided on a surface of at least one of the substrates facing the other substrate, wherein the adhesive layer is formed by an ultraviolet-curing epoxy adhesive composition comprising a light-initiator which produces a cationic polymerization initiator upon irradiation with ultraviolet rays and an epoxy compound having two or more epoxy groups per molecule.

Abstract: An information recording medium including a substrate, an optional intermediate layer arranged on the substrate, and a recording layer arranged on the intermediate layer on the substrate, the recording layer including a low melting metal selected from the group consisting of In, Te, Sn, Pb and Bi and a metal compound selected from a metal sulfide, a metal fluoride and a metal oxide. The recording layer further contains a metal having a high surface tension of not less than 600 dyne/cm within temperatures from its melting point to a temperature higher than the melting point by 300.degree. C., the concentrations of the metal varying along the depth direction of the recording layer in such manner that the concentration of the metal on the side facing the substrate is higher than that of the metal on the opposite side where the metal on the side facing the substrate may be in the form of islands.

Abstract: Improvement in an information recording medium comprising two disc-shaped substrates, said two substrates being combined with each other directly or via ring-shaped spacers by an adhesive, and a recording layer for writing or reading information with laser beam which is provided on the inner surface of at least one substrate, wherein a layer of chlorinated polyolefin is provided between the substrate and the recording layer and further on the area where the substrate is combined with another substrate or the spacers, and said adhesive is a UV-curable epoxy adhesive which is arranged on the chlorinated polyolefin layer, optionally, via a primer layer.

Abstract: An optical information recording medium is described, comprising two disc substrates, which are adhered directly or through a convex portion formed on at least one of the substrates or a spacer provided between the substrates by an adhesive layer, and a recording layer which is capable of recording and/or reading information by laser beam and which is provided on a surface of at least one of the substrates facing the other substrate, wherein the adhesive layer satisfies formulae (1), (2) and (3)d/G.gtoreq.0.05 (1)5.times.10.sup.2 .gtoreq.G.gtoreq.5 (2)200.gtoreq.d.gtoreq.20 (3)wherein G is the coefficient of shearing elasticity (kg/cm.sup.2) of the adhesive layer at 23.degree. C., and d is the thickness (.mu.m) of the adhesive layer.

Abstract: A laser recording material is described, comprising a transparent glass base and a recording layer capable of writing and/or reading information by means of a laser, wherein said glass base has an undercoating layer between the glass base and the recording layer, comprising a carboxyl group-containing polymer or a maleic anhydride copolymer.