Sony Corporation

Dexerials Corporation

Minoru Kikuchi

Jun Nakano

Fuminori Takase

Yoshihiro Akimoto

Akio Koshita

Nobuhiro Saito

Katsuhisa Aratani

Hiroshi Nakayama

Toshiyuki Kashiwagi

Toru Abiko

Hiroyuki Takemoto

Takashi Ohgi

Masaki Kagawa

Minoru Matsuura

Yoshiaki Nakata

Yoshio Shirai

Mitsuhiro Abe

Takeshi Yoshida

Hiroyuki Kawasaki

Noriko Kikuchi

There is provided an optical recording medium substrate including a polycarbonate in which an average molecular weight is in a range from 15000 to 16000, and mass per unit volume at 25° C. is in a range from 1.1930 g/cmto 1.2000 g/cm.

Optical recording medium substrate, optical recording medium, and method of manufacturing optical recording medium substrate

An optical recording medium includes a first disk, a second disk, and an adhesive layer for bonding the first disk to the second disk. The first disk and the second disk each include a substrate having a first surface and a second surface and having a gradient on an outer peripheral portion of the second surface, two or more information signal layers disposed on the first surface, an intermediate layer disposed between adjacent information signal layers, and a cover layer covering the two or more information signal layers and the intermediate layer. The second surface of the substrate included in the first disk faces the second surface of the substrate included in the second disk with the adhesive interposed therebetween.

Optical recording medium and method for manufacturing the same

Provided is an optical recording medium including: two discs, each of which includes a substrate and a plurality of recording layers; and an attachment layer which is provided between the two discs and includes ultraviolet curable resin, wherein thickness of each of the substrates in the two discs is equal to or greater than 0.3 mm and equal to or less than 0.545 mm, wherein transmittance of the two discs is equal to or less than 20%, and wherein inversion rates on both surface sides of the attachment layer are equal or substantially equal to each other, and are equal to or greater than 70%.

Optical recording medium and manufacturing method of the same

An optical recording medium includes: a substrate; an information recording layer formed on the substrate for recording and reproducing an information signal by irradiation with light; and a light transmission layer formed on the information recording layer and transmitting the light, the storage elastic modulus of the light transmission layer at &#x2212;5&#xb0; C. being within a range of 1500 MPa or less.

Optical recording medium, and method for producing optical recording medium

In an optical disc in which an information signal is recorded/reproduced by irradiating a laser beam to a disc substratein which an information signal portionhas been provided on one principal plane from the side where the information signal portionexists, a clamp reference surfaceis set to the information signal portionside of a replica substrateconstructing the optical disc. The clamp reference surfaceis set to a flat surface and a thickness of the replica substratein a clamping areais set to be larger than that of the convex-shaped replica substratein an information recording area. The replica substratein which a periphery of a center holeis thicker than the information recording areais used.

Optical recording medium its manufacturing method and injection molding apparatus

In an optical disc, an information signal area on which an information signal can be recorded and/or reproduced is formed on a major surface of a disc substrate thereof; a light transmitting layer which can transmit a laser beam used in a process for recording and/or reproducing the information signal is formed on a side on which the information signal area is present; and a clamp reference plane is arranged on a major surface of the light transmitting layer in a clamp region. If the optical disc is clamped by a chucking unit of a drive, it is clamped by making the clamp reference plane on the major surface of the light transmitting layer contact with a mounting surface of a table for mounting the disc, and making a magnetic metal plate contact with the major surface of the disc substrate, and then sandwiching the optical disc between.

Optical recording medium and method of manufacturing the same

On a replica substrate, a reflection layer, a first dielectric layermade of ZnS&#x2014;SiO, a recording layermade of a phase change type recording material, and a second dielectric layermade of ZnS&#x2014;SiOare successively formed. In addition, a reaction protection layermade of SiNor SiOis formed on the second dielectric layer. As a result, an information signal portionis composed. A light transmissivity sheet is formed through an adhesive layer so that the light transmissivity sheet coats an information signal portion. As a result, a light transmission layer is composed. When the reaction protection layeris not formed, a reaction protection resin layer made of an ultraviolet ray setting resin is formed so that the reaction protection resin layer coats the information signal portion

Optical disc and fabrication method thereof

There is provided an optical recording medium, in which a light transmitting layer is formed on a disc substrate, having less deflection and being excellent in recording/reproducing properties. In an optical disc, an information signal area on which an information signal can be recorded and/or reproduced is formed on a major surface of a disc substrate thereof; a light transmitting layer which can transmit a laser beam used in a process for recording and/or reproducing the information signal is formed on a side on which the information signal area is present; and a clamp reference plane is arranged on a major surface of the light transmitting layer in a clamp region. If the optical disc is clamped by a chucking unit of a drive, it is clamped by making the clamp reference plane on the major surface of the light transmitting layer contact with a mounting surface of a table for mounting the disc, and making a magnetic metal plate contact with the major surface of the disc substrate, and then sandwiching the optical disc between.

The present invention provides an apparatus and method for forming a protective film on a disc-shaped recording medium including providing a turnable having a center aperture, setting the disc-shaped recording medium having a center opening on the turnable with the center opening being aligned with the center aperture, covering at least the center opening of the disc-shaped recording medium with a rotating disc having a portion larger in diameter than the center opening of the disc-shaped recording medium, and supplying a protective film material to the center of the rotating disc and simultaneously rotating the turnable, the disc-shaped recording medium, and the disc to cause an outward radial flow of the protective film material off the disc and onto the disc-shaped recording medium so that the protective film is obtained and has thickness with a small variation.

Disc-shaped recording medium with a protective film

Optical disc having specified track pitch, push-pull signal, and cross-track signal

Optical Disc

A phase-change optical disc has a recording layer formed from a phase-change material switchable between a crystalline state and an amorphous state. The recording layer is illuminated signal-wise by a light is focused onto the recording layer to change the phase thereof from crystalline to amorphous, to thereby write an information signal onto the recording layer. The phase-change material contains a GeSbTe alloy. The recording layer is formed by sputtering in an Ar gas atmosphere containing at least either N,or O,gas or both. The optical recording medium exhibits improved durability after repeated recording and maintains a stable and good write/read characteristic even after repeated cycles of signal recording.

When applying a coating film by a spin coating method on a disc-shaped recording medium, the film thickness difference between the inner rim and the outer rim of the disc has to be suppressed. To this end, a coating liquid is supplied to a center portion of the disc-shaped recording medium and a rotary disc, as a center shaft of a rotary disc is inserted into a recess formed in a turntable on which the disc-shaped recording medium is set and the disc-shaped recording medium and a rotary disc are run in rotation. The coating liquid is spread under the centrifugal force caused by rotation for forming a coating film on the disc-shaped recording medium.

Method and apparatus for manufacturing disc-shaped recording medium

An improved optical recording medium is provided, and includes a surface of the optical recording medium having at least pits and grooves formed therein, a recording layer formed adjacent the surface of said optical recording medium, and a light transmissive layer formed adjacent the recording layer. Information is recorded and/or reproduced by irradiation of light from an optical pickup employing an objective lens having a numerical aperture of 0.7 or larger through the light transmission layer. At least a surface layer of said light transmissive layer is formed of a material having a Young's modulus of 70 GPa or larger thereby greatly reducing or eliminating scratches from the surface of the optical recording medium while allowing for an increase in the storage capacity of the optical storage medium.

Optical recording medium

The present invention provides an apparatus and method for forming a protective film on a disc-shaped recording medium including providing a turntable having a center aperture, setting the disc-shaped recording medium having a center opening on the turntable with the center opening being aligned with the center aperture, covering at least the center opening of the disc-shaped recording medium with a rotating disc having a portion larger in diameter than the center opening of the disc-shaped recording medium, and supplying a protective film material to the center of the rotating disc and simultaneously rotating the turntable, the disc-shaped recording medium, and the disc to cause an outward radial flow of the protective film material off the disc and onto the disc-shaped recording medium so that the protective film is obtained and has a thickness with a small variation.

Growing community of inventors

Miyagi, Japan

Minoru Kikuchi