Sony Corporation

Takashi Shimouma

Goro Fujita

Jun Nakano

Shigeki Takagawa

Kimihiro Saito

Masataka Shinoda

Koji Ashizaki

Yuji Kuroda

Tetsuhiro Sakamoto

Takeshi Miki

Masahiko Kaneko

Shintaro Tanaka

Ariyoshi Nakaoki

Yasuhito Tanaka

Manami Miyawaki

Masato Nakakura

An optical information recording medium in which recorded information is stably stored for long time in the initial state, signals are not deteriorated by a laser beam for reproduction at the time of signal reproduction, the quality does not change in normal long-term storage, the write characteristic is held, a manufacturing cost is reduced, a margin in the manufacture process is assured, and excellent recording/reproducing characteristics are obtained in the wide range of linear speeds and recording powers is provided. An optical information recording mediumis formed by sequentially stacking a first information recording layer, an intermediate layer, a second information recording layer, and a protection layeron a substrate. As a material of a recording layerof the second information recording layer, a material having a composition expressed by [(ZnS)(SiO)](SbX)(where 0&#x3c;x&#x2266;1.0, 0.3&#x2266;y&#x2266;0.7, 0.8&#x2266;z&#x2266;1.0, and X is at least one element selected from the group consisting of Ga, Te, V, Si, Zn, Ta, Sn, and Tb) is used. H

Optical information recording medium and recording/reproducing method therefor

An optical disc recording medium is irradiated with laser light having a predetermined laser power to deform an irradiated portion of a substrate into a protruding portion. Since the substrate is deformed so as to have protruding portions, a reflecting layer arranged on the substrate is also deformed so as to have protruding portions. For a pit, the deformed state of a protruding portion allows to obtain a reproduced signal level equivalent to that in each land. For a land, the deformed state of a protruding portion allows to obtain a reproduced signal level equivalent to that in each pit. Since the deformed state of each protruding portion can be controlled on the basis of the power of the laser light for irradiation, pit-to-land deformation and land-to-pit deformation can be performed by setting the laser power. Thus, recorded data can be rewritten on the optical disc recording medium recorded with the data using a combination of pits and lands formed in the substrate.

Recording device, recording method, disc manufacturing method and optical disc recording medium

An optical recording medium is provided. The optical recording medium includes at least a reflective film and a cover layer on a substrate; main data by a combination of pit and land are recorded on the substrate; a write-once recording is made to be possible on the reflective film by irradiating a laser light; sub-data are recorded by a mark that is formed by the irradiation of laser light for the write-once recording with respect to the reflective film; a reproducing signal level at portion where said mark is formed increases for the land of specified length; the mark by which the reproduced level decreases at the portion where the mark is formed is formed for an optical disc recording medium manufactured by physical copy; the reflective film is composed of an Ag-alloy film of AgX(0&#x3c;x&#x3c;100); and the X is selected from Ti, W, Ta, V, Mo, Nb and Zr.

Optical recording medium

In an optical disk, a substrate has main data recorded in the form of a combination of pits and lands on one side thereof, and at least a reflective layer and cover layer are stacked on the substrate to cover the pits and lands on the substrate. To the optical disk, sub data is recorded in the form of marks formed by irradiating writing-power laser light to the reflective layer. The marks are formed so that reading signal level will be raised where the marks are formed while it will be lowered where the marks are formed in a counterfeit disk produced based on an authenticated disk, namely, the reading signal level where the marks are formed is different in polarity between in the authenticated and counterfeit disks. Further, in a player for the optical disk, discrimination is made between the authenticated and counterfeit disks by detecting the sub data recorded in the optical disk and judging whether the value of the detected sub data has been read at a correct polarity.

Optical-disk recording medium, playing apparatus and method for same, and recording apparatus and method for same

In order to improve reproduction characteristics of a magneto-optical recording medium in a case of being subject to a magnetically induced super resolution readout process utilizing a blue-violet laser beam, there is provided a magneto-optical recording medium having a surface roughness of 0.3 nm or less on a surface of a substrate on which recording/reproduction magnetic layers are formed or a surface of a dielectric film formed on the substrate.

Magneto-optical recording medium

A magneto-optical recording medium comprising a light-transmitting substrate 1 on which a dielectric layer 2, a memory layer 3 having perpendicular magnetic anisotropy, an intermediate layer 4 having in-plane magnetic anisotropy or slight perpendicular magnetic anisotropy, a recording layer 5 having perpendicular magnetic anisotropy, a dielectric layer 6, a metal layer 7, and a protective layer 8 are formed in a stacked form, the recording medium adapted to be magnetized for recording by a process comprising the step of modulating a first thermal condition and a second thermal condition according to a recording signal, wherein a stacked film 9 composed of the memory layer 3, the intermediate layer 4 and the recording layer 5 has a total thickness of from 1000 to 1500 .ANG., the dielectric layer 6 has a thickness of from 500 to 1500 .ANG., and the metal layer 7 has a thickness of from 250 to 1500 k. The magneto-optical recording medium permits a recording laser light to be used with an increased power margin, without causing any increase in the laser power level. Where the thickness of the memory layer is set in the range from 20 to 70 nm, an enhanced reproduction signal output is obtained.

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Kanagawa, Japan

Takashi Shimouma