Abstract: A process for manufacturing an optical recording medium having in order, a substrate, a recording film and a protective substrate and having a predetermined size, in which the protective substrate is stacked on the substrate using an adhesive layer at least outside a recording area of the recording film. The process comprises a step for cutting out an optical recording medium of a predetermined size, by using a cutting edge, from the optical recording medium of a work size, which is larger than the predetermined size. The work-sized optical recording medium comprises a substrate having the recording film on its surface, a work-sized protective substrate provided on the work-sized substrate using an adhesive layer at least in an area outside of a recording area, including an outside area of the predetermined size.

Abstract: An information recording medium including a substrate, a recording layer, a protective layer, a print layer on the protective layer, and a barrier layer located intermediate the print layer and the recording layer.

Abstract: A hybrid information recording medium provided with an IC module and an optical recording layer as information storage means, which can avoid the influence of heat generated at the IC module on the optical recording layer. The hybrid information recording medium comprises a first substrate which retains the IC module. The first substrate does not contact the optical recording layer.

Abstract: Disclosed herein is an information recording medium to be illuminated with an optical radiation beam, comprising a substrate having a surface provided with a preformat comprising a servo track and forming a sectional shape, in transverse to the track, which comprises a concavity provided between two convexities, each having a flat top, and a light reflecting layer being formed by application of a coating liquid over the surface of the substrate, wherein the concavity has the sectional shape of an open trapezoid having a rectangular part, the trapezoidal part has a pair of parallel opposite sides and a pair of sloping sides constituting walls of the trapezoidal part, one of the parallel sides constituting the bottom of the trapezoidal part being shorter than the opposite side, and the rectangular part is adjacent to the side constituting the bottom of the trapezoidal part.

Abstract: A process for patterning a substrate by forming electrodeposited layers on the substrate so as to correspond with two or more kinds of patterns has the steps of preparing an electrodeposition original plate having conductive patterns respectively corresponding with patterns in which respective conductive patterns are laid bare and conductive patterns are insulated from each other in such a manner that the electrodeposited layers can be respectively independently formed on the conductive patterns successively, forming the electrodeposited layers on the respective conductive patterns and transferring the electrodeposited layers formed on the respective conductive patterns, to a substrate.

Abstract: An optical recording medium has a substrate, a recording layer having a bare portion at the end face, and a protecting layer. The bare portion of the recording layer and the vicinity thereof are resinified so as to be substantially incapable of optical recording.

Abstract: There is provided a reproducible molding die comprising a base structure having an unevenness pattern, and a cleaning layer disposed on the surface of the base structure having the unevenness pattern, wherein the cleaning layer is removable while substantially retaining the unevenness pattern of the base structure. By using above-mentioned molding die, a possible molding residue left in a molding step can easily be removed together with the cleaning layer.

Abstract: An optical recording medium provided with a substrate has a preformat on the surface thereof, a recording layer, and a protecting layer. The substrate has an electrodeposit layer arranged in a pattern corresponding to the preformat on the surface of the substrate.

Abstract: An apparatus for producing an optical recording medium in a sheet form, having a resin melt-extruding device that forms a resin sheet, a first heated roller having a predetermined unevenness pattern, and a second heated roller disposed opposite thereto. Further, the apparatus has a conveying device that conveys the resin sheet, in a substantially melted state, between the first and second rollers, which transfer an unevenness pattern to a surface of the resin sheet. The apparatus also has a temperature control device to gradually cool the resin sheet.

Abstract: A method produces a molding die for an information recording medium, having a mold surface with a prescribed unevenness pattern comprising a projection; the projection having different etching velocities along its projected thickness; and defining a pair of convergent opposite inclining side slopes. Each slope of the pair forms an acute inclining angle with respect to extension of the mold surface. A pattern-forming layer is formed comprising a common metal element throughout its thickness and an additional element differing in composition from the common metal element in the thickness direction of the pattern-forming layer. The common metal element and the additional elements have different etching velocities in the thickness direction of the pattern-forming layer. The pattern-forming layer is selectively etched with a common etchant to form the projection.

Abstract: A mold for molding a plurality of substrates for an information recording medium includes a fixing member, a plurality of units fixed to the fixing member, and a molding cavity. Each of the units has a preformat pattern with a surface corresponding to information recording medium formed on its surface, and the molding cavity is disposed opposite to the units so that the preformat patterns face the molding cavity.

Abstract: An optical recording medium, comprising a substrate and a recording layer covered on the outer surface with a protective member comprising a heat-shrinkable material subjected to heat shrinkage, a process for preparing the same and its optical recording and reproducing system.

Abstract: There is provided a cast molding die for an information recording medium, having a mold surface with a prescribed unevenness pattern including a projection; wherein the projection has at least one pair of opposite side slopes each of which forms an acute angle with respect to the extension of the mold surface. By using the cast molding die having the above-mentioned projection with a three-dimensional shape, a defect such as lack in the resultant information recording medium is prevented.

Abstract: An optical recording medium is formed by applying a coating liquid to form a light-reflecting layer on a substrate having a surface provided with a pre-format pattern comprising a concavity and a convexity. The concavity is designed to have a sectional shape of a trapezoid having a pair of parallel opposite sides, a shorter one of which constitutes the bottom of the concavity, and a pair of sloping sides. Each sloping side forms a (solid part) angle .theta. of not larger than 35 degrees with respect to the extension of the substrate surface. The concavity has a depth d larger than .lambda./4n wherein .lambda. is the wavelength of an optical radiation beam with which the optical recording medium is illuminated for recording and/or reproduction and n is the refractive index of the substrate.

Abstract: A method for preparing a substrate for an information recording medium, which comprises injecting a liquid resin into a mold for cast molding of a substrate for information recording medium having a plurality of units of mold for cast molding having an uneven preformat pattern on the surface arranged therein and solidifying the resin, and a mold for molding of the substrate.

Abstract: An optical recording medium comprises an optical recording layer provided on a substrate, a protective material and a bond layer for bonding the optical recording layer to the protective material, the bond layer having a thermoplastic adhesive comprising at least one of (A) at least one selected from an ethylene-acrylic acid copolymer and an ethylene-acrylate ester copolymer and (B) an ethylene-maleic anhydride-acrylic acid terpolymer; and (C) a tackifier.

Abstract: An optical recording medium comprises an optical recording layer provided on a substrate, a protective material and a bond layer for bonding the optical recording layer to the protective material, the bond layer having a thermoplastic adhesive comprising at least one of (A) at least one selected from an ethylene-acrylic acid copolymer and an ethylene-acrylate ester copolymer and (B) an ethylene-maleic anhydride-acrylic acid terpolymer; and (C) a tackifier.

Abstract: A process for producing an optical recording medium in a sheet form, including the steps of: melt-extruding a resin to form a resin sheet; and passing under pressure the resin sheet in a substantially melted state between a first heated roller having a predetermined unevenness pattern and a second heated roller disposed opposite thereto, thereby to transfer the unevenness pattern to a surface of the resin sheet.

Abstract: A molding die for an information recording medium substrate having a prescribed unevenness pattern comprising a track portion and an information pit portion which has a planar shape of a polygon wherein at least one diagonal is substantially parallel to the track portion. Such molding die provides an information recording medium substrate without lack in the periphery of a pre-format.

Abstract: An optical recording medium for performing writing and reading on a pit by use of a light of beam comprises an optical recording layer comprising a porous layer.