Tdk Corporation

Other

Mitsubishi Rayon Company, Limited

Hideki Hirata

Hiroyasu Inoue

Hajime Utsunomiya

Tatsuya Kato

Koji Mishima

Masaki Aoshima

Tsuyoshi Komaki

Hiroshi Shingai

Naoki Hayashida

Isamu Kuribayashi

Takashi Kikukawa

Atsuko Kosuda

Motohiro Inoue

Toshifumi Tanaka

Hiroyuki Endo

Kenji Yamaga

Tomoki Ushida

Yasufumi Takasugi

Giichi Shibuya

Hiroshi Takasaki

Kazuki Suzawa

Takashi Namioka

Kazuo Fukunaga

Toshikazu Hosobuchi

Masanori Kosuda

Tsuneo Kuwahara

Setsuko Shibuya

Takuya Tsukagoshi

Hitoshi Arai

Keiji Koga

Toshihiko Ishida

Yoshitomo Tanaka

Hideki Ishizaki

Atsuko Motai

Osamu Murakami

Hiroshi Tanabe

Jiro Yoshinari

Lambertus Hesselink

Mark E McDonald

Masatoshi Nakayama

Andrew J Daiber

Michael V Morelli

Hideaki Miura

Sergei L Sochava

Mamoru Usami

Suguru Takayama

Kenji Uchiyama

Masaki Sobu

Tsutomu Kotani

Yasuhiro Takagi

Hiroshi Chihara

Tokuyuki Honda

Juichi Fujimoto

Shin-ichi Tezuka

Kouji Hayama

Ryota Uchiyama

Shunichi Nishimura

Sanjoy Ghose

Akira Itoga

Hiroshi Shinngai

Jajime Utsunomiya

A series of optical recording media is provided to reduce a burden on an optical pickup by introducing a standardized idea among a plurality of optical recording media. In the series of optical recording media, optical recording media are of a plurality of types, each optical recording medium including a plurality of planar recording and reading layers with no projections and depressions for tracking control, and a servo layer with projections and depressions for tracking control. The plurality of optical recording media have different numbers of stacked recording and reading layers, and the positions of the servo layers with respect to the corresponding light incident surfaces are standardized among the plurality of optical recording media.

Series of optical recording media

Simple design of a multilayer optical recording medium is achieved while suppressing interlayer crosstalk and confocal crosstalk in the multilayer optical recording medium. Simple recording and reading control by a recording and reading unit is also achieved. The multilayer optical recording medium includes at least three or more recording and reading layers deposited one above the other with intermediate layers interposed therebetween, and information can be read by light irradiation from the layers. The intermediate layers have film thicknesses of two types or less, and all the recording and reading layers except the recording and reading layer farthest from a light incident surface have substantially the same optical constant.

Multilayer optical recording medium

The multilayer optical recording medium with six or more recording and reading layers disposed one above the other has at least two or more recording and reading layer groups. The recording and reading layer groups each include a plurality of recording and reading layers successively disposed one above the other. The reflectance of each of the recording and reading layers in a stacked state decreases in the order from a front side near a light incident surface toward a back side far from the light incident surface. A recording and reading layer nearest the front side among the recording and reading layers in the recording and reading layer group nearer the back side has a reflectance in a stacked state higher than that of a recording and reading layer nearest the back side among the recording and reading layers in the recording and reading layer group nearer the front side.

In a multilayer optical recording medium, it is an object to suppress generation of crosstalk while reducing an interlayer distance of recording and reading layers. In an optical recording medium including three or more recording and reading layers, a first distance, and a second distance greater than the first distance by 3 &#x3bc;m or more are alternately defined as interlayer distances of recording and reading layers.

Optical recording medium, and series of optical recording media

Efficient recording and reading are achieved in an optical recording medium including servo layers and recording and reading layers. The optical recording medium includes: a first servo layer having a projection and a depression for tracking control that are formed in a first spiral direction; a second servo layer having a projection and a depression for tracking control that are formed in a second spiral direction opposite to the first spiral direction; and a plurality of recording and reading layers having a flat structure with no projection and depression for tracking control. Information is recorded on each of the plurality of recording and reading layers while tracking control is performed using the first servo layer or the second servo layer.

Optical recording medium and optical recording-reading method

An optical recording and reading method is provided in which the information necessary for recording and reading layers is quickly acquired to reduce the seek time during reading and recording. The optical recording and reading method is used for an optical recording medium that includes a plurality of recording and reading layers and a servo layer. Information is recorded on or read from the recording and reading layers by irradiating them with a recording and reading beam while the servo layer is irradiated with a servo beam to perform tracking control. When information is recorded on the recording and reading layers, control information necessary for subsequent recording and reading to be performed on the recording and reading layers is recorded on the servo layer. When the subsequent recording or reading is performed, the control information on the servo layer is consulted, and then the recording or reading is performed on the recording and reading layers.

Optical recording-reading method and optical recording medium

An optical recording medium including recording and reading layers and a servo layer increases the recording capacity thereof. In the optical recording medium including the plurality of recording and reading layers and the servo layer, the servo layer has a groove and a land that can be used to perform tracking control with a long-wavelength servo beam. Information is recorded on the recording and reading layers with a recording and reading beam having a wavelength shorter than the wavelength of the servo beam. Recording marks are formed on the recording and reading layers while both the groove and land are tracked.

A next-generation optical recording medium has two or more information layers which include a translucent information layer. The translucent information layer has a recording film and an interface layer, provided adjacent to the recording film on the side of the light incident surface. The recording film is made of a phase change material having SbTeGeelements and elemental ratios. Y satisfies 5&#x2266;y&#x2266;15 and z satisfies 5&#x2266;z&#x2266;15. When In having an elemental ratio of a is further added and x+y+z+a=100 holds, a satisfies 4&#x2266;a&#x2266;15. The interface layer comprises of ZrO&#x2014;CrOfilm thickness of which is in a range of from 2 nm to 10 nm. When ZrO:CrO&#x2550;C:D (mol %), the compositional ratios ZrOand CrOin the ZrO&#x2014;CrOfilm, holds, the C satisfies 20&#x2266;C&#x2266;90, and the D satisfies 10&#x2266;D&#x2266;80, and the C and the D satisfy C+D=100. The ZrOis stabilized ZrOwhich contains YO, when ZrO:YO=(100&#x2212;X):X (mol %), the compositional ratios ZrOand YOin the stabilized ZrO, holds, the X satisfies 2&#x2266;X&#x2266;10.

Optical recording medium and recording film material

An optical recording medium is provided which includes two or more information layers in which an Sb-based eutectic material is used as the material for a recording film of a translucent information layer. There is also provided a recording film material for the optical recording medium. The translucent information layer is configured to include a recording film formed of a phase change material SbGeIncontaining Sb, Ge, and In in an atomic ratio of x:y:z, where 5&#x2266;y&#x2266;15 and 4&#x2266;z&#x2266;15 are satisfied. The recording film further includes Te in an atomic ratio of a, provided that x+y+z+a=100 and 4&#x2266;a&#x2266;15 are satisfied. An interface layer formed of a ZrO&#x2014;CrOfilm having a thickness of 2 nm or more and 10 nm or less is provided on the laser beam incident side of the recording film. When the compositional ratio of the ZrO&#x2014;CrOfilm is given by ZrO:CrO=B:C (mol %), 20&#x2266;B&#x2266;90, 10&#x2266;C&#x2266;80, and B+C=100 are satisfied.

A rewritable phase-change optical recording medium is provided, which includes a substrate, a first information layer, a spacer layer, a second information layer, and a cover layer. The second information layer includes a recording film containing Sb as a main component and V or V and In as second components. When an amorphous mark formed in the recording film is irradiated with a reproduction beam, crystallization of the amorphous mark occurs only in a central portion in the width direction of the amorphous mark. The width direction is orthogonal to the scanning direction of the laser beam. The recording film is formed of a material that exhibits a change in degree of modulation of 5% or less when recorded information is repeatedly reproduced. The change in degree of modulation is a change from when the number of times of reproduction is 100,000 to when it is 400,000.

Rewritable phase-change optical recording medium

It is an object of the present invention to provide a method for recording data in an optical recording medium which can record data in a write-once type optical recording medium at a high linear recording velocity using a laser beam whose recording power is set low. The method for recording data in an optical recording medium according to the present invention is constituted so that data are recorded by a laser beam whose power is modulated in accordance with a pulse train pattern onto an optical recording medium including a substrate, a first recording layer, a second recording layer and a light transmission layer to form a recording mark wherein a recording pulse is divided into (n&#x2212;1) divided pulses and the power of the laser beam is set to a recording power Pw at the peak of each of the divided pulses and set to a first bottom power Pband the levels of the recording power Pw and the first bottom power Pbare determined so that a ratio PbPw of the first bottom power Pbto the recording power Pw falls within a range of 0.1 to 0.5. When the power of a laser beam is modulated using such a pulse train pattern to record data in an optical recording medium, the heating of a recording layer by the laser beam having the recording power Pw can be augmented by the laser beam having the first bottom power Pband therefore, even in the case where data are to be recorded in an optical recording medium at a high linear recording velocity, it is possible to record data in the optical recording medium at a high linear recording velocity using a semiconductor laser having a low output.

Method for recording data in optical recording medium, an apparatus for recording data in optical recording medium and optical recording medium

It is an object of the present invention to provide a method for recording data in an optical recording medium which can record data in a write-once type optical recording medium at a high linear recording velocity using a laser beam having a low recording power. The method for recording data in an optical recording medium according to the present invention is constituted so that when data are to be recorded in an optical recording medium including a substrate, a first recording layer and a second recording layer by projecting a laser beam whose power is modulated in accordance with a pulse train pattern including pulses whose levels are set to levels corresponding to a recording power Pw and a bottom power Pb onto the optical recording medium and forming a recording mark at a predetermined region of the first recording layer and the second recording layer, as a linear recording velocity increases, the power of the laser beam is modulated using a pulse train pattern including a smaller number of pulses whose level is set to a level to the recording power Pw, thereby forming a recording mark. According to the present invention, since the power of a laser beam is modulated using a pulse train pattern including a smaller number of pulses whose level is set to a level to the recording power Pw as a linear recording velocity increases, it is possible to record data in an optical recording medium using a laser beam having a low recording power even when a linear recording velocity is high and on the other hand, it is possible to prevent cross-talk of data from increasing even when a linear recording velocity is low. Therefore, it is possible to employ a semiconductor laser having a relatively low output even when data are recorded at a high linear recording velocity.

An optical recording medium includes an information layer having a recording film. The recording film contains Sb of 79 atomic % to 95 atomic % and Ge of 5 atomic % to 21 atomic % as main components, and is formed of a phase change material which does not contain the elements in the sixteenth group of the periodic table.

Optical recording medium

An optical recording medium includes a substrate, a first recording layer formed on the substrate and containing an element selected from the group consisting of Si, Ge, C, Sn, Zn and Cu as a primary component, and a second recording layer located in the vicinity of the first recording layer and containing Al as a primary component, the optical recording medium being constituted to be irradiated by a laser beam projected onto the side opposite from the substrate and the total thickness of the first recording layer and the second recording layer being equal to or thinner than 40 nm. According to the thus constituted optical recording medium, it is possible to decrease a noise level and improve a C/N ratio in a reproduced signal.

Optical recording medium and method for optically recording data in the same

It is an object of the present invention to provide a method for recording data in an optical recording medium which can form a recording mark having desired length and width in a write-once type optical recording medium. The method for recording data in an optical recording medium according to the present invention is constituted so as to project a laser beam whose power is modulated by a pulse train pattern onto an optical recording medium including a substrate, a first recording layer, a second recording layer and a light transmission layerwherein a recording pulse of the pulse train pattern is divided into (n&#x2212;1) divided pulses and the power of the laser beam is set to a recording power Pw at the peak of each of the divided pulses, set to a second bottom power Pbat a portion immediately after a last divided pulse and set to a first bottom power Pbat other intervals where Pbis higher than Pb

Method for recording data in optical recording medium, and apparatus for recording data in optical recording medium and optical recording medium

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Tokyo, Japan

Hideki Hirata