Sony Corporation

Mitsubishi Rayon Company, Limited

Nissei Plastic Industrial Co., Ltd.

Teijin Chemicals Limited

Nobuyuki Arakawa

Yuji Akiyama

Toshiyuki Kashiwagi

Ken Minemura

Minoru Takeda

Masanobu Yamamoto

Shingo Imanishi

Motohiro Furuki

Hirotsugu Suzuki

Kazutoshi Takayama

Shinsuke Kishi

Kazuki Miyairi

Tokihiro Nishihara

Masaaki Kishimura

Takashi Segawa

Koji Ishihata

Moriyoshi Kaneko

Asao Kurosu

A method of producing a stamper, an optical recording medium produced by molding using the stamper, and a method of producing the same, wherein a base member having a mirror polished main surface and comprising silicon or glass is formed with a resist film; the resist film is exposed by a focused electron beam, an ultraviolet ray laser, etc. and developed so as to form a resist film of a pattern corresponding to relief shapes; the mirror surface of the base member is processed to relief shapes (projecting regions and recessed regions) by dry etching etc. using the obtained resist film as a mask so as to obtain a stamper; the obtained stamper is used for injection molding to form a medium substrate; and an optical recording multilayer film and a protective layer are formed to thereby produce an optical recording medium.

Stamper for producing optical recording medium, optical recording medium, and methods of producing the same

A stamper suppressed in surface roughness, uneven thickness, and deviation of circularity in inner circumference, a method of producing the same, an optical recording medium produced by molding using the stamper, and a method of producing the same, wherein a base member having a mirror polished main surface and comprising silicon or glass is formed with a resist film; the resist film is exposed and developed so as to form a resist film of a pattern corresponding to relief shapes; the mirror surface of the base member is processed to relief shapes (projecting regions and recessed regions) by dry etching etc. using the obtained resist film as a mask so as to obtain a stamper; the obtained stamper is used for injection molding to form a medium substrate; and an optical recording multilayer film and a protective layer are formed to thereby produce an optical recording medium.

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&#x3b4;, 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.

Optical recording medium

A method of producing an information recording medium having enhanced planarity with high productivity, comprising steps of processing a surface of a disk substrate by satin-like finishing, heating and pressing the disk substrate through compression using a stamper having relief shapes so as to transfer the relief shapes to at least one satin-like finished surface of the disk substrate, forming a recording layer on the relief shape surface of the disk substrate, and forming a coating layer on the recording layer, and a production apparatus for the information recording medium, and an information recording medium produced by the method of producing.

Method of producing information recording medium, production apparatus and information recording medium

A recording medium for information signals including a substrate, a signal recording layer provided on one major surface of the substrate and a clamp member having a positioning unit at its center portion and formed of a material that can be magnetically attracted by a magnet. The clamp member is unified to the center portion of the substrate so that the surface of the clamp member will be flush with the substrate surface.

Disk-like recording medium and method for producing the same

An optical disc includes a substrate, and a recording layer and transparent layer formed in this order on the substrate. A light is incident from the transparent layer to write and/or read an information signal. The substrate comprises a first resin layer forming a surface of the substrate on which the recording layer is formed, and a second resin layer having a higher flexural modulus is formed on the first resin layer.

Optical recording medium with a substrate of two different resin layers

An optical recording medium comprises a substrate having one principal surface on which uneven pattern is formed, and adapted so that light is irradiated onto the uneven pattern and recording/reproduction of recording signals are carried out by the irradiated light. The substrate includes an intermediate layer including rigidity rendering material and a surface layer formed on at least one principal surface of the intermediate layer and adapted so that the uneven pattern is formed. As the rigidity rendering material, there are used granulated filling material, plate-shaped filling material and fiber material. In manufacturing such an optical recording medium, the surface layer is disposed in a manner to oppose stamper where reversed uneven pattern is formed and the intermediate layer including rigidity rendering material is stacked on the surface layer. By heating and pressure-fitting such stamper, surface layer and intermediate layer, the surface layer and the intermediate layer are integrated and the reversed uneven pattern is transferred onto the surface layer.

Optical recording medium and method for producing the same

An optical disc molding apparatus is able to mold an optical disc in which the occurrence of swollen portions of trumpet shape on the upper and lower surfaces of on the outer peripheral portion of a disc base may be minimized and in which a burr may be prevented from being produced on the outer peripheral portion of the disc base. In the optical disc molding apparatus having a ring (,) for molding an outer diameter portion of a disc base and holding a stamper (,) for transfer a signal pit, a holding surface of the ring (,) for holding the stamper (,) is formed as the concave and convex surfaces comprising a plurality of concentric land portions (,) and a plurality of concentric groove portions (,). The outer peripheral surface of the stamper (,) is held by each land portion (,) with a pressure.

Optical disc molding apparatus

In the method of manufacturing an optical recording medium according to the present invention, when an optical recording medium having at least first and second minute concave and convex surfaces formed thereon is manufactured, the first and second minute concave and convex surfaces are simultaneously molded on both surfaces of a substrate of the optical recording medium. Therefore, it is possible to manufacture a multilayer optical recording medium having an excellent symmetrical structure with respect to a vertical cross section direction of the substrate, i.e., in the thickness direction of the optical recording medium. Moreover, it is possible to effectively suppress the deformation thereof resulting from curing or shrinkage of an light curing resin or the like, absorption or removal of vapor in the air into or from a substrate, a transparent intermediate film or the like, and so on.

Method of manufacturing optical recording medium

Disclosed is an information recording medium capable of, in the case of recording information signals such as high density information, sufficiently transferring the information signals, and suppressing resonance upon high speed rotation and enhancing the durability of the medium. The medium includes a substrate, a recording layer provided on the substrate for recording an information signal, and a light transmission layer laminated on the recording layer, wherein an information signal is recorded or reproduced on or from the medium by making light incident on the medium from the light transmission layer side. The substrate includes a core layer made from a resin, and a surface layer made from a resin and integrated with the core layer. The surface layer has on its one side plane information signals in the form of irregularities on the recording layer side and has a fluidity which is larger than that of the core layer in the case where both the surface layer and the core layer are in a molten state at the same temperature.

Optical recording medium having substrate of dual transparent layers

An optical disc molding apparatus is able to mold an optical disc in which the occurrence of swollen portions of trumpet shape on the upper and lower surfaces of on the outer peripheral portion of a disc base may be minimized and in which a burr may be prevented from being produced on the outer peripheral portion of the disc base. In the optical disc molding apparatus having a ring (6) for molding an outer diameter portion of a disc base and holding a stamper (5) for transfer a signal pit, a holding surface of the ring (6) for holding the stamper (5) is formed as the concave and convex surfaces comprising a plurality of concentric land portions (21) and a plurality of concentric groove portions (22). The outer peripheral surface of the stamper (5) is held by each land portion (21) with a pressure.

An optical disc substrate having a reduced thickness and sufficient rigidity is provided which can be of a single-plate structure. It can be compatible with a magneto-optic recording and also with a conventional disc driving means. The substrate consists of a disc supporting portion (21) formed around the center of the substrate and of which one side (21a) provides a surface at which the disc is to be mounted on a disc driving means, and a recording portion (22) formed between the disc supporting portion (22) and a circumference of the substrate and of which one side (22a) provides a recording surface. The disc supporting portion (21) is designed thicker than the recording portion (22) so that the disc supporting surface (21a) and the recording surface (22a) will not lie together in a sample plane. A recess 25 may be formed between the recording portion (22) and disc supporting portion (21), and also a projection (27) may be formed along the circumference of the side (22b). Furthermore, one or more functional layer may be formed on the side (22b) opposite to the recording surface.

Optical disc substrate having relatively thicker central supporting

An optical disc molding device has a pair of molds for injection molding a disc substrate within cavities, and a stamper supported within at least one cavity, for molding a data recording surface in such a manner that the inside diameter side of the stamper supporting surface of the cavity protrudes inwardly in the disc thickness direction from the data recording surface. The flatness of a laminated reference plane has thus been deteriorated by burrs occurring on a disc substrate.

Optical disc molding device and molding method for optical disc

A disk substrate molding die is provided in which the quantity of eccentricity of a stamper can be reduced to a small value. The molding die includes a member having mounted thereon a thin plate (19) carrying thereon a recorded transfer signal and an adjusting device consisting of a plurality of pairs of adjusting blocks, each formed of movable blocks (9a) and (9b) and blocks (10a) and (10b) having adjacent surfaces inclined in the moving direction of the movable blocks and common to one another.

Molding dye for disk substrate

A method of forming a protective film for an optical recording medium. A protective film forming ink having a viscosity in a range between 0.9 and 100 ps is applied on a surface of a pad, e.g., a semispherical pad, having a Shore A hardness between 8 and 30. The spherical surface of the pad thus applied with the ink is pressed to a substrate of the optical recording medium on which a reflective layer is formed to transfer the protective film forming ink to the surface of the substrate so as to cover the entire surface of the reflective layer and extend over the peripheral edges. Then, the ink is cured to form the protective film.

Growing community of inventors

Kanagawa, Japan

Nobuyuki Arakawa