Sony Corporation

Etsuro Ikeda

Yuichi Sabi

Fuminori Takase

Takashi Kishi

Masahiro Kikkawa

Takemitsu Sakai

Hiroshi Nakayama

Akitoshi Suzuki

Sohmei Endoh

Jun Shimizu

Toru Abiko

Mitsuo Arima

Mitsuaki Oyamada

Mikio Yoshida

Hiroshi Miura

Itaru Suzuki

Hirotaka Ozawa

Manabu Satoh

Yuji Kawana

Nobuaki Furuichi

Masayuki Takakuwa

A write-once type optical recording mediumhas an inorganic recording film. The inorganic recording filmhas an oxide filmcontaining an oxide of germanium (Ge) and an adjacent filmwhich contains titanium (Ti) and manganese (Mn) and is adjacent to the oxide film

Optical recording medium and method for manufacturing the same

An optical recording medium is an optical recording medium having an inorganic recording film and has a transparent conductive film on the inorganic recording film. The inorganic recording film has a first recording film containing titanium (Ti) and a second recording film containing an oxide of germanium (Ge). The transparent conductive film is provided on the side of the second recording film. The transparent conductive film contains an oxide of tin (Sn).

To accomplish write-once type optical recording mediums that have excellent recording and reproducing characteristics and producibility and that are capable of being fabricated at low cost. A write-once type optical recording mediumhas the structure of which an inorganic recording film, a dielectric film, and a light transmission layerhave been successively formed on a substrate. The inorganic recording filmis composed of a metal filmand an oxide filmsuccessively formed on the substrate. When light is radiated to the inorganic recording film, oxygen is separated from the oxide filmdue to the light catalyst effect, resulting in increasing the oxygen concentration on the metal filmside and largely varying the optical constant.

Write-once type optical recording medium and fabrication method thereof

In an optical recording mediumhaving a configuration in which on one main surface of a substrate, a reflective layer, a lower dielectrics layer, a recording layer, an upper dielectrics layerand a light transmissive layerare sequentially laminated, the lower dielectrics layeris formed of a first lower dielectrics layer and a second lower dielectrics layer that inhibits a material that constitutes the first lower dielectrics layer and a material that constitutes the reflective layerfrom reacting, and the upper dielectrics layeris formed of a first upper dielectrics layer and a second upper dielectrics layer that inhibits a material that constitutes the first upper dielectrics layer and a material that constitutes the light transmissive layerfrom reacting.

Optical recording medium and method for manufacturing same

A write once optical recording medium has an inorganic recording film which includes an oxide film having germanium oxide (GeO) as a principal component, and a metal film adjacent to the oxide film, the metal film having a titanium/silicon alloy (TiSi) as a principal component. According to this arrangement, it is possible to construct an inexpensive write once optical recording medium with large strength capable of high density recording by using a short wavelength light source and an optical system with a high numerical aperture having excellent characteristics.

Write once optical recording medium

A recording medium and a recoding medium master, and a method of manufacturing the recording medium which comply with the standard of recording/reproducing characteristic established in the MD standard while enabling precise discrimination of the pit track and groove track and optical detection of the pits by optical pickup and the like are provided. Pits and grooves are arranged on a surface of a disc-shaped substrate so as to form a grooves and the ratio is from 1.00 exclusive to 1.13 inclusive. It is preferable that the track pitch of the grooves is from 1.50 &mgr;m inclusive to 1.70 &mgr;m exclusive. The width of the pits and grooves in the radial direction of the substrate is the same.

Magneto-optical recording medium having pit pitch greater than groove pitch

A magneto-optical recording medium is disclosed with which magneto-optical recording is performed by a magnetic-field modulation method and which enables stable recording characteristics to be realized even if the intensity of the recording magnetic field is somewhat changed. When a magneto-optical recording medium incorporating a signal recording layer made of TbFeCoCr and arranged such that a magneto-optical recording operation is performed with respect to the signal recording layer by the magnetic-field modulation method is manufactured, the signal recording layer is formed such that the total quantity of Tb and Cr contained in the signal recording layer is 24&plusmn;1 at %. After the signal recording layer has been formed, exposure to stem by 30&times;10,Torr&middot;sec to 10000&times;10,Torr&middot;sec or exposure to oxygen by 10&times;10,Torr&middot;sec to 50&times;10,Torr&middot;sec is performed to oxidize the surface of the signal recording layer.

Magneto-optical recording medium

An optical disc in which a desired exchange reciprocal action is displayed between two sorts of the rare earth-transition metal alloy films to realize optimum recording/reproducing characteristics, and a manufacturing method for the optical disc. To this end, an optical disc 1 includes a first rare earth-transition metal alloy film containing rare earth elements and transition elements and a second rare earth-transition metal alloy film layered on the first rare earth-transition metal alloy film. The second rare earth-transition metal alloy film has a composition different from that of the first rare earth-transition metal alloy film and contains rare earth elements and transition elements. An oxidized area defined between the first rare earth-transition metal alloy film and the second rare earth-transition metal alloy film has an oxygen content not higher than 2.5 atom % and a thickness not larger than 7 nm.

Optical device and manufacturing method thereof

A DC sputtering system improved in prevention of fusion of a substrate and electric corrosion of a pallet revolving shaft due to the flow of negative electric charges at the time of production of an optical disk. The system includes a pair of electrodes, a negative electrode and a positive electrode, wherein the negative electrode is composed of a target plate made from a target material such as Si and a backing plate on which the target plate is fixedly placed, and the positive electrode is composed of a pallet disposed opposite to the negative electrode. A substrate of an optical disk is mounted on the positive electrode side through a disk base using an inner peripheral mask and an outer peripheral mask. Each of the inner peripheral mask and the outer peripheral mask is made from or covered with an electrically insulating material such as teflon or ceramic. This prevents the flow of negative electric chargers from being concentrated at the inner peripheral mask and the outer peripheral mask, to thereby protect the substrate from being fused.

DC sputtering system

A magneto-optic disc comprised of a substrate on which are formed a recording layer and a protective film and on which information is recorded by a magnetic head floating above the magneto-optic disc by a predetermined floating distance at least at the time of recording the information, wherein the height of the projections on the surface of the protective film of the magneto-optic disc is smaller than the floating distance of the magnetic head.

Magneto-optical disc having a protective film with minimal projections

In a magneto-optical recording medium having a substrate, a recording layer having at least a rare earth-transition metal alloy film formed on the substrate, and a dielectric layer formed on the recording layer, a depth of penetration in the recording layer for an element derived from the dielectric layer is set to 70 .ANG. or less from an interface between the recording layer and the dielectric layer in a depth-directional film structure analysis by an Auger electron spectroscopy. Accordingly, mixing of impurities into the recording layer can be suppressed to thereby lower the value of the required recording magnetic field.

Method for producing magneto-optical recording medium

In a magneto-optical recording medium having a substrate, a recording layer having at least a rare earth-transition metal alloy film formed on the substrate, and a dielectric layer formed on the recording layer, a depth of penetration in the recording layer for an element derived from the dielectric layer is set to 70.ANG. or less from an interface between the recording layer and the dielectric layer in a depth-directional film structure analysis by an Auger electron spectroscopy. Accordingly, mixing of impurities into the recording layer can be suppressed to thereby lower the value of the required recording magnetic field.

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Miyagi, Japan

Etsuro Ikeda