Tdk Corporation

Kazuki Suzawa

Hideki Hirata

Yasufumi Takasugi

Giichi Shibuya

Takashi Namioka

Toshikazu Hosobuchi

Kazuo Fukunaga

Hiroyuki Arioka

Mamoru Usami

Kenji Yamaga

Tomoki Ushida

Hiroshi Kobayashi

Tsuyoshi Komaki

Toshifumi Tanaka

Atsushi Koyama

Tsutomu Kotani

Takeshi Umega

Mikio Domon

Michiki Naganawa

It is an object of the present invention is to provide an apparatus for discriminating an optical recording medium and a method for discriminating an optical recording medium which can reliably discriminate the kind of an optical recording medium even in the case where the optical recording medium to be discriminated is formed with periodical undulation in the circumferential direction thereof. The apparatus for discriminating an optical recording medium according to the present invention includes a first electrode, a second electrode, an alternate current signal generation circuitfor applying an alternate current A to the first electrode, a detection circuitfor detecting a level of an alternate current B appearing at the second electrode, and a control circuitfor controlling the operations of the alternate current signal generation circuitand the detection circuit

Apparatus for discriminating optical recording medium and method for discriminating optical recording medium

The present invention provides a method and an apparatus for discriminating the type of an optical recording medium and the number of recording layers in the medium. The apparatus includes a first electrode and a second electrode placed in the vicinity of a light transmission layer of the recording medium, an alternating current signal generation circuit for applying an alternating current A to the first electrode, a detection circuit for detecting the level of an alternating current B appearing at the second electrode, and a control circuit for controlling the operations of the alternating current signal generation circuit and the detection circuit, and a table provided in the control circuit.

A surface treatment of a light transmissive layer by spin coating is carried out in a simple way at low cost. When a light transmissive layer is to be formed by spin coating, the transfer of an information recording layer is carried out using a resin stamper having a convex portion in an outer peripheral portion. At the same time, an inclined plane (concave portion) is formed on the side of a substrate (member on which transfer is performed). As a result, coating is achieved in such a manner that a raise in the outer peripheral portion is prevented from being noticeable.

Stamper for fabrication of optical recording medium, method of forming information recording area and light transmissive layer, and optical recording medium

It is an object of the present invention to provide an apparatus for discriminating an optical recording medium which can reliably discriminate the kind of an optical recording medium even in the case where the optical recording medium to be discriminated is warped and formed with periodical undulation in the circumferential direction thereof. The apparatusfor discriminating an optical recording medium according to the present invention includes a first electrodea second electrodea third electrodea fourth electrodean alternating current signal generation circuitfor applying an alternating current signal A to the first electrodeand the third electrodea detection circuitfor detecting the level of an alternating current signal Bappearing at the second electrodeand the level of an alternating current signal Bappearing at the fourth electrodea supporting mechanismfor supporting the first electrodeand the second electrodea supporting mechanismfor supporting the third electrodeand the fourth electrodea driving mechanismfor vertically moving the supporting mechanisma driving mechanismfor vertically moving the supporting mechanismand a control circuitfor controlling the operations of the alternating current signal generation circuitthe detection circuitthe driving mechanismand the driving mechanismand a tableis provided in the control circuit

It is an object of the present invention to provide an apparatus for discriminating an optical recording medium and a method for discriminating an optical recording medium which can reliably discriminate the kind of an optical recording medium even in the case where the optical recording medium to be discriminated is warped. The apparatus for discriminating an optical recording medium according to the present invention includes a first electrode, a second electrode, an alternating current signal generation circuitfor applying an alternating current signal A to the first electrode, a detection circuitfor detecting the level of an alternating current signal B appearing at the second electrode, a supporting mechanismfor supporting the first electrodeand the second electrode, a driving mechanismfor vertically moving the supporting mechanism, and a control circuitfor controlling the operations of the alternating current signal generation circuitand the detection circuitand the driving mechanism

There is provided a mold component which makes it possible to mold a substrate for an optical recording medium which enables a functional layer having a uniform thickness to be formed thereon without using a resin-coating assisting member. A stamper holder holds a stamper thereon, and has a generally hollow cylindrical shape. An insertion hole formed through a central portion of the stamper has a diameter which is larger than an outer diameter of a cavity-side end of the stamper holder at a higher temperature of the holder than a normal temperature, and is slightly smaller than the outer diameter at the normal temperature of the holder. The cavity-side end inserted into the insertion hole at the higher temperature of the stamper is grasped by a rim of the insertion hole which is reduced in diameter at the normal temperature of the stamper.

Mold component and mold assembly

An optical recording mediumcomprises a disc bodya white ink layerprovided on the label sideof the disc bodyand an ink receiving layerprovided on the surfaceof the white ink layerThe mean roughness (Ra) of the surfaceof the white ink layeris set not greater than 0.2 &#x3bc;m. A step radially extended is left on the surfaceof the ink receiving layerand set not greater than 1.0 &#x3bc;m. As the mean roughness (Ra) of the surfaceof the white ink layeris not greater than 0.2 &#x3bc;m or as the step on the ink receiving layeris not greater than 1.0 &#x3bc;m, high printing quality can be secured when printing is done with an ink-jet printer.

Optical recording medium and method of producing the same

It is an object of the present invention to provide an optical recording medium wherein hardness of the surface on the incident-light side is high and warping of the optical recording medium is suppressed. The optical recording medium according to the present invention comprises a substrate, a recording layerprovided upon the substrate, a light transmission layermade of ultraviolet curable resin provided upon the functional layer, and a hard-coat layerprovided upon the light transmission layer, wherein the thickness of the light transmission layeris 50 &#x3bc;m or greater and its pencil hardness is HB or less. Thereby, warping of the optical recording medium arising due to cure shrinkage of the ultraviolet curable resin making up the light transmission layercan be effectively suppressed. Moreover, the hard-coat layeris provided upon this light transmission layer, so the occurrence of scratches on the surface of the optical recording medium can be effectively prevented.

Optical recording medium and production method therefor

The invention provides an optical recording medium having excellent weatherability and a process for producing the same. The optical recording medium is provided with an organic dye layer, a reflecting layer and a protective layer in this order on a light-transmittable substrate. The organic dye layer contains an organic solvent in an amount of 2% to 15% by weight based on the organic dye. A solution, prepared by dissolving an organic dye in an organic solvent, is applied onto the light-transmittable substrate by a spin coating method to form an organic dye layer. A reflecting layer is formed on the organic dye layer without performing a drying treatment of the organic solvent in the organic dye layer, followed by forming the protective layer on the reflecting layer. The result is an optical recording medium containing an organic solvent in an organic dye layer in an amount of 2% to 15% by weight based on an organic dye.

Process for producing optical recording medium and optical recording medium

The irradiation time and/or the irradiation power of a laser beam is varied to perform multi-level recording on a recording layer in five stages or more. On the recording layer of an optical recording medium , defined contiguously are virtual recording cells within a groove along tracks arranged at track pitches of 1 to 1.5 &mgr;m. The time and/or the irradiation irradiation power of the laser beam is modulated in five stages or more corresponding to the information to be recorded on each of the virtual recording cells in order to form recording marks A- G having five stages or more of different sizes and/or optical transmittance. The overall optical reflectivity of each of the virtual recording cells is modulated in multi-stages to vary in five stages or more the entire reflectivity level of the reading laser beam used upon reading in the virtual recording cell including the outside of the recording mark.

Optical recording medium and optical recording method

Fluorinated alcohol for manufacturing optical recording medium and optical recording medium using the same

An optical disk substrate of resin, comprising a center hole and being composed of an inner circular-projected portion and an outer flat circumferential portion, the inner circular-projected portion having a circular projection projecting from at least one major surface of the substrate, the maximum height of the circular projection measured from the major surface of the outer flat circumferential portion being equal to or larger than 0.5 mm, the optical disk substrate is designed to satisfy the following equation or inequality: V/V.sub.0 &lt;1.5, where V stands for the volume of the circular-projected portion, and V.sub.0 stands for the volume of an annular body having the same radius as the circular-projected portion and the same thickness as the outer flat circumferential portion, and having a center hole of the same size as the center hole.

Growing community of inventors

Tokyo, Japan

Kazuki Suzawa