Abstract: The present invention provides an optical disc which is constituted by a substrate, a recording layer, and a protection layer and is irradiated with a laser beam from the protection layer side. The optical disc has the substrate whose diameter is greater than 50 mm, the recording layer provided on the substrate, and the protection layer which is layered on the recording layer and thinner than the substrate and on which a recording or reproducing laser beam is incident. The total thickness of the optical disc is 0.7 mm or more.

Abstract: A wound laminate obtained by laminating a plastic film composed of an aromatic polycarbonate comprising bisphenol A as an aromatic dihydroxy component, and a protective film composed of an aromatic polyester, using an intervening adhesive having a weak adhesive strength of 3-50 gf (0.0294-0.49 N), and winding the laminate. The wound laminate is used as a transparent protective layer (protective film) for an optical disk to fabricate a film surface side-incident optical disk.

Abstract: An optical disc (10) includes a substrate (11), which is formed from either a resin-impregnated paper produced by impregnating a paper with a resin, or a resin-coated paper produced by coating a surface of a paper with a resin, and a recording layer (13), wherein the resin contains at least one resin selected from the group consisting of polycarbonates, bisphenol A epoxy resins, copolymers of methyl methacrylate and styrene, and copolymers of acrylonitrile and styrene. Furthermore, a method of manufacturing an optical disc (20) includes: providing a recording layer sheet by forming tracks on a recording base material; and bonding the recording layer sheet to a resin-impregnated paper or a resin-coated paper, thereby providing a recording layer (13) formed from the recording layer sheet on the substrate (11).

Abstract: An electronic device is provided that has excellent portability because it can be folded to a compact size at coupling means. In addition, a first display portion of a first display unit and a second display portion of a second display unit can form a single, large-screen display portion when the first display unit is rotated 90° clockwise and the second display unit is rotated 90° counterclockwise.

Abstract: An optical recording medium illuminated by light from a light source as near-field light using a focusing lens whose numerical aperture exceeds 1 to perform recording and/or reproduction is provided, wherein a composite layer in which a high refractive index material portion having a refractive index higher than that of a light-transmissible material portion is mixed in the light-transmissible material portion is provided on the surface of a light incident side of the optical recording medium. With an average refractive index of the composite layer being high, a numerical aperture controlled by a refractive index of a surface layer can be made large to obtain higher resolution and higher durability against contact with a lens or the like.

Abstract: A laminating apparatus 20 for a DVR as an optical disc comprises front side peeling means 24 for peeling a protective film P1 from a protective label L having the protective film P1 and a release-liner D adhered thereto, a peel plate 25 for peeling off the release-liner D from the protective label L from which the protective film P1 has been peeled, and laminating means 29 for laminating the protective label L after the peeling of the protective film P1 and the release-liner D to a DVR recording substrate by laminating the protective label L to the DVR recording substrate B with a predetermined pressing force.

Abstract: A coating composition containing a solvent and a coating agent having an ionizing radiation-curable compound as a principal component thereof, wherein under the following condition for the concentration a (wt %) of the coating agent in the coating composition 0<a?60, the concentration a of the coating agent and the surface tension b (dyne/cm) of the coating composition satisfy the following relationship b?(?a/15)+26, is applied onto a surface of a protective film 11 and curing is carried out to form a hard coating layer 12. Even in the case that projections or foreign bodies are present on the surface of the protective film 11, the hard coating layer 12 can conceal these and hence can have high surface smoothness.

Abstract: An optical disc-producing sheet 1, which has an adhesive layer 11 having a specific heat capacity after curing of not more than 1.9 J/g·° C. at 80° C. and a protective sheet 12, is laminated onto an information recording layer 3 (a laminate of a reflecting layer 31, a dielectric layer 32, a phase change layer 33 and a dielectric layer 32?) formed on an optical recording medium substrate 2. According to this optical disc, recorded information can be reproduced accurately even in the case that recording/erasure or reproduction of information has been carried out repeatedly.

Abstract: An initialization method of an optical recording medium having a plurality of optical recording layers capable of reducing initialization unevenness due to light interference caused at the time of initialization without deteriorating information recording/reproducing signal characteristics of the optical recording layers is provided.

Abstract: An optical recording medium capable of improving uniformity of thickness of a protective film and suppressing warping. The medium is configured to include a substrate, an optical recording film formed on the substrate, and a light transmitting protective film formed above the optical recording layer, wherein the protective film includes a polymer sheet produced by melt casting and an adhesive layer for bonding the polymer sheet to the optical recording layer. As the polymer sheet, a polycarbonate sheet, a cyclic polyolefin sheet, etc. can be used. As the adhesive layer, an ultraviolet curing resin, a heat curing resin, an epoxy resin-based adhesive agent or a pressure-sensitive tackiness agent may be used alone or mixed or stacked.

Abstract: An optical disc comprising a substrate and a recording layer and a light-transmitting layer, laid on a substrate one upon the other in the order mentioned. A light beam is applied to the recording layer through the light-transmitting layer, to record and/or reproduce data on the disc. The light-transmitting layer is composed of at least two material layers laid one on the other and having different refractive indices. The disc is designed to set the spherical aberration caused by an objective lens that focuses the light beam used to record and/or reproduce data, at a value close to a minimum.

Abstract: An optical recording medium capable of suppressing warps arising during a long time use and a method of producing the same, which has the configuration of comprising a substrate 13, an optical recording layer 14 formed on the substrate 13 and a light transmitting protective film 17 formed on the optical recording layer 14, wherein the protective film 17 includes a polymer film 16 having a thermal shrinkage coefficient of 0.02% or less and an adhesive layer 15 for adhering the polymer film 16 to the optical recording layer 14. As the polymer film 16, those produced by a melt cast method, subjected to annealing processing in advance or having a residual solvent of 0.3% by weight or less in the film may be preferably used.

Abstract: An initialization method of an optical recording medium having a plurality of optical recording layers capable of reducing uneven initialization due to light interference caused at the time of initialization without deterioration of information recording/reproducing signal characteristics of the recording layers is provided.

Abstract: The present invention relates to an optical disc for use as a recording medium in an optical disc drive, which has a transparent protection film (120) formed on a recording layer on one plane of the disc substrate (110) and a printing label film 130 being of approximately the same film quality and film structure as the transparent protection film (120) formed on the other plane thereof. The printing label film (130) is a synthetic resin film made mainly of polycarbonate and formed on the disc substrate by screen printing, etc. Thus, the optical disc has the same film quality and film structure on the respective one and the other planes, which prevents occurrence of skew caused by the deformation due to the asymmetry of the structure along the thickness direction of the optical disc. The optical disc has a function to present contents of information recorded therein with the printing label film provided on the other plane of the disc substrate.

Abstract: The present invention provides an optical disc which is constituted by a substrate, a recording layer, and a protection layer and is irradiated with a laser beam from the protection layer side. The optical disc has the substrate whose diameter is greater than 50 mm, the recording layer provided on the substrate, and the protection layer which is layered on the recording layer and thinner than the substrate and on which a recording or reproducing laser beam is incident. The total thickness of the optical disc is 0.7 mm or more.

Abstract: An optical disc-producing sheet 1, which has an adhesive layer 11 having a specific heat capacity after curing of not more than 1.9 J/g·° C. at 80° C. and a protective sheet 12, is laminated onto an information recording layer 3 (a laminate of a reflecting layer 31, a dielectric layer 32, a phase change layer 33 and a dielectric layer 32′) formed on an optical recording medium substrate 2. According to this optical disc, recorded information can be reproduced accurately even in the case that recording/erasure or reproduction of information has been carried out repeatedly.

Abstract: A protective film for optical disks comprising an acrylic adhesive layer disposed on one face of a light transmitting substrate film, wherein a change in transmittance (X) expressed by equation [1] is 10% or smaller and the amount of elution of halogen ions and the amount of alkaline ions from an acrylic adhesive constituting the acrylic adhesive layer are each 10 ppm or smaller; and an optical disk using the protective film. X(%)=[(Ta−Tb)/Ta]×100  [1] (Ta: an initial transmittance of light of 405 nm through the protective film, Tb: a transmittance of light of 405 nm through the protective film after the protective film is left standing at 80° C. in 85% RH for 1,000 hours). The protective film is used for protecting the information recording layer of the optical disk and the functions of recording and regeneration of the optical disk are not adversely effected.

Abstract: An optical recording medium capable of suppressing film thickness irregularity of interlayer between a plurality of optical recording layers and effects of warps of a transfer substrate and arising of dusts and burrs problems, etc. and a method of producing the optical recording medium are provided. An optical recording medium has a structure wherein at least two optical recording layers (11, 13) stacked via an interlayer 12 and a light transmitting layer 14 provided on the optical recording layer are provided at least one surface of a medium substrate 10, for performing recording and reproducing by irradiating a light to the optical recording layers (11, 13) through the light transmitting layer 14, and the interlayer includes at least one layer of ultraviolet curing resin film made to be a film in advance and is a film formed with an uneven shape corresponding to a recording pit or an uneven shape (12p) to be a guide groove on its surface and cured.

Abstract: There are provided a multilayer disc manufacturing apparatus and method, capable of computing a rotational eccentricity of a disc with no contact with the disc and a high accuracy, and producing the disc with lower costs without having to rotate the disc or perform any complicated operations. The multilayer disc manufacturing apparatus (100) is for manufacturing a multilayer disc by bonding one disc (220) to another disc (210).

Abstract: An initialization method of an optical recording medium having a plurality of optical recording layers capable of reducing uneven initialization due to light interference caused at the time of initialization without deterioration of information recording/reproducing signal characteristics of the recording layers is provided.