Tdk Corporation

Hitachi Metals, Ltd.

Proterial, Ltd.

Kenji Yamaga

Tsuyoshi Komaki

Koji Mishima

Daisuke Yoshitoku

Mamoru Usami

Yoshimi Sakai

Atsushi Koyama

Hideki Hirata

Tomoki Ushida

Takashi Yamada

Kinya Aota

Hitoshi Arai

Tadashi Fujieda

Hajime Murakami

Takahiko Kato

Hiroyuki Satake

Kousuke Kuwabara

Isamu Takahashi

Kazuki Suzawa

Hironori Kakiuchi

Hisaji Oyake

Yuuichi Kawaguchi

Hiroaki Takahata

Seiki Shimazu

Yuichi Namikawa

Mikio Domon

Hiroyasu Inoue

Hiroshi Shingai

Hideaki Miura

Giichi Shibuya

Teiichiro Oka

Junichi Ide

Shigeru Yamatsu

An alloy structure has an arbitrary shape dimension which has high uniformity in the distribution of the element composition. The alloy structure contains Fe and at least four elements, which are selected from the group consisting of elements from atomic number 13 to atomic number 79 included in Group 3 to Group 16 of the periodic table of the elements and have a ratio of the atomic radius to an Fe atom of 0.83 or more but 1.17 or less, each of Fe and the four elements is contained in an atomic concentration range of 5 at % or more but 30 at % or less, a difference in atomic concentration between at least four elements among the at least four elements and Fe is in a range of less than 3 at %, and the alloy structure has, a column crystal in which the at least four elements and Fe are solid-dissolved.

Alloy structure and method for producing alloy structure

An alloy structure which has high uniformity in the distribution of the element composition and the mechanical strength and excellent high-temperature strength and corrosion resistance, contains Fe and at least four elements, which are selected from the group consisting of elements from atomic number 13 to atomic number 79, included in Group 3 to Group 16 of the periodic table of the elements, and have a ratio of the atomic radius to an Fe atom of 0.83 or more but 1.17 or less, each of the elements in an atomic concentration range of 5 at % or more but 30 at % or less, a difference in atomic concentration among the at least four elements and Fe is in a range of less than 3 at %, and the alloy structure has, as a main crystal, a column crystal in which the at least four elements and Fe are solid-dissolved.

An optical recording medium and a method of recording and reproducing of the optical recording medium are provided, which are capable of recording and reproducing data with reliability even when blue or blue violet laser light is used as irradiation light. The optical recording medium has a recording layer in which a recording mark composed of a plurality of cavities is formed by irradiation of the laser light. The recording layer is configured so that, in a plan view taken in a direction of irradiation of the laser light, cavities lying in an area of the center and its vicinities of the recording mark, out of the plurality of cavities, include cavities greater than ones lying around the area.

Optical recording medium and method of recording and reproducing of optical recording medium

An optical recording medium includes a substrate and a plurality of recording layers laminated via at least intermediate layers, at least one of the recording layers other than a recording layer farthest from a light incidence plane among the plurality of recording layers containing at least one metal M selected from a group consisting of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn and La and an element X which can combine with the metal M upon being irradiated with a laser beam for recording data, thereby forming a crystal of a compound of the element X with the metal M. According to the thus constituted optical recording medium, it is possible to record data in and reproduce from a farthest recording layer from a light incidence plane in a desired manner and it is possible to record data in and reproduce from recording layer(s) other than the farthest recording layer from the light incidence plane in a desired manner.

Optical recording medium

An optical recording medium including a light transmitting layer having a uniform thickness formed on a substrate, in which a burr or stripping hardly occurs at the inner periphery of the light transmitting layer, and a manufacturing method and a manufacturing device of the optical recording medium are provided. An optical recording mediumis manufactured by a manufacturing method including: molding a disc-like shaped substrateincluding an information recording faceA on one side; forming a light transmitting layerthinner than the substrateon the information recording faceA; forming a circular cutin the light transmitting layer; and punching out an area inside the cutby a punching toolto form a center holeA in the light transmitting layerand a center holein the substrate

Optical recording medium, and manufacturing method and manufacturing device thereof

The optical recording medium is an optical recording medium having at least one information layer including a recording film, characterized in that the recording film is formed by a phase change material including at least Sb, Ge and Mg as main components.

An inexpensive optical recording medium is provided that can ensure recording and reproduction of data even in case of using blue or blue-violet laser light as irradiation light and can be stored for a long time. The optical recording medium includes a recording layer. The recording layer includes a recording portion and a covering portion covering at least one side of the recording portion in a thickness direction of the recording portion. The recording portion and the covering portion are substantially formed from a plurality of types of common constituent elements. Composition ratios of the constituent elements are different between the recording portion and the covering portion.

Optical recording medium and method for manufacturing the same

An optical recording medium includes a support substrate, and a light transmission layerthat is disposed so as to come in contact with the support substrate. At least one of a refractive index of the support substrate and a refractive index of the light transmission layer, and an extinction coefficient of the support substrate and an extinction coefficient of the light transmission layer is different. As such, according to the invention, a reflective layer is not formed between the support substrate and the light transmission layer, such that the support substrate and the light transmission layer directly come in contact with each other. Accordingly, since at least one of the refractive index and the extinction coefficient is different, reflection occurs at the interface between the support substrate and the light transmission layer. Therefore, data held by a plurality of pits, that are arranged on the support substrate in a spiral shape or a concentric shape, can be correctly read out.

Optical recording medium and method of manufacturing the same

An optical recording medium and a method for manufacturing the same, which offer to an information layer formed on a spacer layer the same electric characteristics such as a jitter and a noise as those of an information layer formed on a substrate, are provided. A convexo-concave pattern is transferred to a face of a spacer layer, which is opposite to the side of a substrate, so that a radial width of a convex portion is limited to be 53% or larger and 72% or smaller with respect to a radial pitch of concavity and convexity. A second information layer (information layer on the spacer layer) is formed in accordance with the convexo-concave pattern.

Optical recording medium having a relationship between convex width and track pitch

An intermediate for an optical recording medium, according to the present invention, is an intermediate produced beforehand for manufacturing an optical recording medium that has a central mounting hole formed in a central portion thereof and one or more kinds of functional layers formed on a surface thereof, for enabling at least one of information recording and information reproduction. The intermediate has a provisional central hole, which is smaller in diameter than the central mounting hole, formed in a central portion thereof. This makes it possible to drop resin in the vicinity of the center of the intermediate without using a disk-shaped member, in performing spin coating on the intermediate, whereby it is possible to make the layer of applied resin substantially uniform in thickness.

Intermediate for optical recording medium and method of manufacturing the optical recording medium

The invention relates to a light-receiving element for receiving a reflection of laser light irradiated to a rotating multi-layer recording medium having a plurality of information recording layers stacked one over another and for converting the light into an electrical signal, an optical head having the element for recording information in the multi-layer recording medium or reproducing information recorded therein, and an optical recording/reproducing apparatus and a method of optical recording and reproduction. The invention provides a light-receiving element, an optical head, an optical recording/reproducing apparatus, and a method of optical recording and reproduction which make it possible to eliminate a noise component superimposed on reflected light from a multi-layer recording medium to reproduce an RF signal of high quality. The light receiving element receives a reflection of laser light irradiated through an objective lens to a rotating multi-layer recording medium having a plurality of information recording layers stacked one over another through a return path optical system and converts the reflected light into an electrical signal. The element has a first light-receiving section having a circular light-receiving region and a second light-receiving section disposed adjacent to the outer circumference of the first light-receiving section in the form of a circle concentric therewith.

Light-receiving element, optical head, optical recording/reproducing apparatus, and method of optical recording and reproduction

An optical recording medium is provided, which are capable of recording and reproducing data with reliability even when blue or blue violet laser light is used as irradiation light. The optical recording medium includes a substrate, and a recording layer formed over the substrate and having its optical characteristic changed by irradiation of the laser light. The recording layer is substantially composed of Bi and O, and the ratio of the number of the O atoms to the total number of Bi and O atoms in the recording layer is 63-73%.

In an information recording medium according to the present invention, a recording layer, a first layer, and a second layer are formed so that a thermal conductivity of the first layer that contacts one surface of the recording layer and a thermal conductivity of the second layer that contacts another surface of the recording layer are both lower than a thermal conductivity of the recording layer and a track pitch is in a range of 0.1 &#x3bc;m to 0.5 &#x3bc;m, inclusive.

Optical recording medium having multiple layers of different thermal conductivities

A disc-shaped optical recording medium formed by carrying out a film formation process on a disc-shaped substrate material and completed by forming a center hole at the last step is manufactured in a manner such that no eccentricity will occur when the recording medium is loaded onto a drive. At the last step of an optical disc manufacturing process, i.e., at the time of opening a hole in the center partof the disc-shaped substrate materialformed with at least a resin layer on one side thereof, the center partis removed in a manner such that the diameter of the chucking center holeis larger on the disc-shaped substrate materialside than on the light transmitting resin layerside of the disc-shaped optical recording medium, thereby manufacturing the disc-shaped optical recording medium

Method for manufacturing discoid optical record medium and discoid optical record medium

An optical recording medium comprising: a substrate; and a recording layer, formed on substrate; and characterized in that recording layercontains palladium oxide as the main component and contains oxygen at an amount of 19 atom % to 61 atom %.

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Tokyo, Japan

Kenji Yamaga