Abstract: In a method for producing an optical recording medium by forming a recording film on a substrate by means of vapor deposition of a pigment material in a high vacuum condition, the temperature (° C.) of an evaporation vessel for heating and evaporating the pigment material is not more than 2.5 times as high as the evaporation starting temperature of the pigment material.

Abstract: The present invention provides a protective film with high mechanical strength free from dust. A protective film 14 of an optical recording medium 2 is formed by applying and curing a composition for protective films obtained by dispersing in a curable binder material a first lubricant compatible with said binder material and a second lubricant incompatible with said binder material but compatible with said first lubricant. The incompatible second lubricant is stably and homogeneously dispersed to enhance lubricity and slidability while any excessive amount of the lubricant does not deposit on the surface of the protective film. The binder material is desirably photocurable.

Abstract: An optical recording medium is provided in which a recording layer contains a salt-forming dye between an ion of an azo metal complex of the following formula (I) and an ion of a cyanine dye of the following formula (II), having a complex index of refraction in the wavelength region of recording light and/or reading light whose imaginary part k is up to 0.20, or at least one of azo oxovanadium metal complexes having an azo compound of the following formula (III) as a ligand and metal complexes having azo compounds of the following formulae (IV) and (V) as a ligand. Recording and reading can be carried out at a conventional wavelength or a short wavelength of about 630-690 nm or both.

Abstract: By keeping the imaginary number portion k of the complex index of refraction of the film of the light absorbing layer 3, the mean film thickness dav of the light absorbing layer 3, and the absorbency A related thereto within an appropriate range, the present invention provides an optical information recording medium with good recording sensitivity and playback properties, which makes possible high speed recording by increasing the sensitivity to the recording beam and stable recording with sufficient reflectivity, and which can reduce jitter. In the present invention, 0.13≦A≦0.21 where A (Abs) is the absorbency of the light absorbing layer at the wavelength of the recording beam; and 6.0≦k.dav≦12.0 where k is the imaginary number portion of the complex index of refraction of the film in the light absorbing layer and dav (nm) is the mean film thickness of the light absorbing layer, at the wavelength of the recording beam.

Abstract: An optical recording medium includes a substrate having light transmission properties, which has laminated on a main surface thereof a recording layer and a metal reflection layer. The recording layer is made of a compounded organic dye thin film which contains a specified aromatic amine compound in an amount of not smaller than 3% by weight but below 30% by weight based on the total weight of the recording layer and a specified asymmetric cyanine dye having absorption to light having a wavelength of 500 to 700 nm in an amount of not smaller than 30% by weight but below 97% by weight based on the total weight of the recording layer. The recording layer is applicable to a short-wavelength (500 to 700 nm) semiconductor laser so that an optical recording medium according to the DVD-ROM standards having excellent stability of the dye film and allowing a decrease in jitter component upon high density recording.

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: Focusing and tracking can be stably performed using an optical information recording medium in which a high reflectivity and a large reflective change amount can be attained, and the reflectivity change amounts of the lands and grooves are set equal to each other by forming, between a transparent substrate and a first protective layer, an interference layer containing at least one material selected from the group consisting of Au, Ag, Cu, Si, and Ge. Even if information is recorded on the lands and the grooves, it can be recorded/reproduced without any crosstalk from an adjacent track.

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: ##STR1## wherein R.sub.1 and R.sub.9 are each independently an alkenyl group, an aryl group or a heteroaryl group; R.sub.2 to R.sub.8 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: 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: 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. The distance between the recording surface of the substrate and the light incident surface is smaller than a thickness of the substrate, and a surface roughness "R" of the light incident surface meets a relationship represented by the following formula (1):R.ltoreq..lambda./(8n) (1)wherein .lambda.

Abstract: A description is given of a rewritable optical information medium having an IPIAIM stack comprising a phase-change recording layer sandwiched between two dielectric layers, a light-absorbing layer of a material like Si, Ge, Mo, or W, a third dielectric layer, and a metal mirror layer. The light-absorbing layer reduces the difference in light absorption between the amorphous state and the crystalline state to a minimum, thus reducing the recording mark distortion. The presence of the light-absorbing layer in this position ensures that the optical phase difference between the amorphous and the crystalline state is almost zero, making the medium suitable for land-groove recording.

Abstract: A phase-change optical disc that is adapted to weaken a self-sharpening effect and to be driven by a pulse width modulation system. In the disc, a dielectric layer formed on the surface of a recording layer and a heat flow control layer is sequentially disposed. The heat flow control layer is formed to include a material having a high heat conductivity and a material having a low heat conductivity.

Abstract: A phase-change recording medium having a recording layer (4) made of a Ge--Sb--Te alloy, comprises an interface reflection control layer (3) provided on a laser beam incident side of the recording layer (4). The interface reflection control layer (3) has an extinction coefficient k and a refractive index n, simultaneously satisfying: k.gtoreq.0.22n+0.14, k.ltoreq.0.88n-0.19, and n.ltoreq.2.8. From the foregoing, it follows that the intensity ratio between the reflected wave from and the incident wave on the interface between the recording layer (4) and the interface reflection control layer (3) is led to a specified range.As a result, for the recording layer (4) the ratio (Ac/Aa) of the light absorption rate (Ac) in the crystalline state to the light absorption rate (Aa) in the amorphous state increases. Furthermore, the optical contrast also has a sufficiently high value. It is therefore possible to produce a high quality readout signal in recording by overwriting.

Abstract: The present invention is to provide a method for manufacturing the PCE optical information recording disk under control of not only the crystallization velocity but also the complex index of refraction and thus the reflectance on the disk surface.The PCE optical information recording disk is suitable to be used under the constant angular velocity (the constant rotational numbers wherein the disk has a characteristic that the crystallization velocity is designed to become faster from inside area of the disk to outside area in the radical direction thereof under control of not only the crystallization velocity but also the complex index of refraction and thus the reflectance on the disk surface.

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: 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: 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 cavity surface-forming plate of a mold for injection-molding a plastic substrate is coarsely polished, and then a surface for defining a cavity is applied with electroless Ni-P plating. The surface of the plating is polished with abrasive grains to obtain surface roughness of Ra.ltoreq.2.0 nm and Rmax.ltoreq.22 nm. The plastic substrate molded with the mold has smoothness equivalent to the polished plating surface. A concave-convex pattern for forming pits may be formed on the cavity surface. A magnetic disk or an optical disk provided with the substrate makes it possible to realize the near contact system for a magnetic or magneto-optical head. Thus, it is possible to realize high density recording.

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.