Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Canon Kabushiki Kaisha

Matsushita Electrical Industrial Co., Ltd.

Origin Electric Company, Limited

Keiji Nishikiori

Eiji Ohno

Motoyoshi Murakami

Mamoru Shoji

Masaru Yamaoka

Makoto Usui

Mitsuro Moriya

Masahiro Birukawa

Morio Tomiyama

Yasumori Hino

Kazuya Hisada

Yuuko Tomekawa

Kiyoshi Uchida

Shinya Abe

Kenji Kondo

Masahiro Nakamura

Masahiko Tsukuda

Kazuhiro Hayashi

Kenzo Ishibashi

Hironobu Nishimura

Sou Miyata

Masahiko Kotoyori

Masahito Konishi

Koujiro Tanaka

An optical disc includes a reflective film formed on concave and convex marks after the concave and convex marks are synchronized with the integral multiple of a channel bit length and formed in accordance with modulated main information. Thereafter, continuous or intermittent laser light synchronized with the integral multiple of the channel bit length is irradiated at intervals longer than the longest one of the concave and convex marks in accordance with a spiral track formed in a circumferential direction of the concave and convex marks, whereby an optical characteristic of the reflective film is changed to form a recordable mark and sub-information necessary to reproduce the main information is recorded in a superimposition manner.

Optical disc, optical disc manufacturing method, optical disc recording device and optical disc reproduction device

An optical disk manufacturing apparatus which employs first and second signal layer forming mechanisms, a reflection layer forming mechanism, a light transmission layer forming mechanism and first, second and third transportation mechanisms. The apparatus further includes a liquid material supplying mechanism, a first and second rotation mechanism, first and second hardening light radiation apparatuses, a ring-shaped mask portion, and a mask transfer mechanism.

Optical disc production apparatus

The present invention provides a method for manufacturing a multilayer information recording medium including at least two information recording portions and a resin layer interposed between the information recording portions, both of which are disposed on a signal substrate. The method includes a first process of forming a predetermined information recording portion on one principal surface of the signal substrate and a second process of passing a part of a resin-containing coating, which is supplied on a screen having an application region with a plurality of first pores and a removal region with a plurality of second pores, through the first pores by sliding a squeegee on the screen so as to form a coating layer on the predetermined information recording portion, and curing the resin contained in the coating layer so as to form the resin layer. The first process and the second process are carried out respectively a predetermined number of times. In each second process, at least a part of the resin-containing coating that has not been applied on the predetermined information recording portion and that remains on the screen is allowed to pass through the second pores so as to be removed from the screen surface.

Multilayered information recording medium and process for producing said multilayered information recording medium, and apparatus for producing multilayered information recording medium and screen constituting said production apparatus for producing multilayered information recording medium

An optical disc () to and from which information can be reproduced and recorded by laser irradiation is provided with a first recording layer () and a second recording layer (). The first recording layer () has a first recording mark () that is formed in a spiral track. The second recording layer () is behind or in front of the read-side surface of the first recording layer (), and neither a wobble track nor a track for reproducing or recording information by laser irradiation is formed on the second recording layer (). On the second recording layer () are formed, by laser irradiation, a second recording mark () that is positioned in the radial direction of the optical disc according to a predetermined position on the spiral track of the first recording layer. The optical disc () ensures the secrecy of the copyright protected information that is recorded thereto and the copyright protection function of the optical disc (), and is resistant against illegal copying.

Multiple recording layers optical disc having physical position information of pre-recording marks

A transparent protective layer () having a thickness of 100 &#x3bc;m is formed of a resin film (), a boundary layer () and an adhesive layer () on a signal recording layer (). When nf, ni and na are the indices of refraction of the resin film (), the boundary layer () and the adhesive layer (), respectively, the relationship among nf, ni, and na satisfies any one of the following equation: na&#x3c;ni&#x2266;nf; na&#x3e;ni&#x2267;nf; na&#x3c;nf&#x2266;ni; or na&#x3e;nf&#x2267;ni, and the relationship among nf, ni, and na satisfies the following equation |nf&#x2212;ni|&#x3c;|nf&#x2212;na|. At this time, a protrusion () and a scratch () are optically buried within the boundary layer (), reducing scattering of laser beams and disturbance in the wave front which occur in these portions, and thereby, the error rate can be reduced.

Optical information recording medium and method for manufacturing the same

An optical information recording medium includes a substrate, n information recording layers provided on the substrate, and spacer layers, each of which is provided so as to be interposed between the information recording layers, wherein each of (n&#x2212;1) or more of the information recording layers has a layer number information part that is formed in correspondence with one or more recording marks X and contains layer number information, where n represents an integer of not less than 2, and the layer number information is information used for determining which a given information recording layer is among the n information recording layers. Each recording mark X has a length in a circumferential direction longer than a length of a recording mark Y used for recording another information in the information recording layers.

Optical information recording medium, its information recording/reproducing method, and information recording/reproducing device

A method for producing a multilayer information recording medium the method including: holding a substrate; feeding a resin onto the substrate; and removing the excess resin by moving a squeegee throughout the entire surface of the substrate. The substrate may have a resin-coated region, onto which the resin is to be applied, and a non-resin-coated region, onto which the resin is not to be applied. In this case, the resin-coated region has a smaller contact angle with the resin than the non-resin-coated region. The method for producing a multilayer information recording medium may further include, prior to feeding a resin onto the substrate, subjecting a specified area of the substrate to an oil repellent treatment to increase the contact angle of the specified area with the resin.

Multilayer information recording medium and production method therefor

An optical information recording medium that has a simple structure and with which warpage is kept to a minimum even under environmental changes over a wide range, and a method for manufacturing this medium are provided. The optical information recording medium is an optical information recording medium used for the reproduction of recorded information and for recording and reproduction, including a substrate having an information recording layer, and a light transmitting layer that covers the information recording layer and is composed of a radiation curable resin, wherein a warpage adjusting layer for adjusting warpage of the light transmitting layer caused by temperature changes is disposed on the opposite side of the substrate from the side on which the information recording layer is formed. There is included at least a temperature region that satisfies the relationship that the coefficient of linear expansion CL of the light transmitting layer&#x3c;the coefficient of linear expansion SL of the warpage adjusting layer, at temperatures under room temperature.

Optical information recording medium and method for manufacturing same

An optical information recording medium has tolerance to warping. The optical information recording medium includes at least one information recording layer on a main surface of a substrate and a light-transmitting layer. The substrate includes a clamp area and an information recording area in accordance with the information recording layer. In the light-transmitting layer, the average thickness of a second area corresponding to the clamp area is thinner than the average thickness of a first area corresponding to the information recording area.

Optical information recording medium

An optical disc cutting apparatus capable of suppressing an unnecessary deflection component and unnecessary light intensity variation component and manufacturing a optical disc suitable for a high definition, high precision and high density optical disc. The optical disc cutting apparatus includes a light beam controller including at least one of an optical modulator for controlling the light intensity of light beam emitted from a laser beam source and an optical deflector for controlling the deflection amount of the light beam in the radial direction on an optical disc original master, a deflection error detector for detecting a deflection error in the radial direction included in the light beams controlled by the light beam controller, a second optical deflector, which is disposed between the light beam controller and the deflection error detector, for deflecting the light beams in the radial direction, and a feedback controller for feeding back a feedback signal using the deflection error in the radial direction to the second optical deflector.

Optical disc cutting apparatus and method for manufacturing optical disc

A magneto-optical recording medium includes a substrate and a reproducing layer and a recording layer provided on the substrate. A recording magnetic domain is provided in the recording layer by heating the recording layer by irradiation with light and applying a recording magnetic field to the recording layer in such a manner that information is recorded in the recording layer. The recording layer is a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface, and the magnetic film holds the recording magnetic domain formed therein. The magneto-optical recording medium further comprises a intermediate layer and a reproducing aid layer between the reproducing layer and the recording layer. Saturated magnetization of the reproducing aid layer increases with an increase in the temperature of the reproducing aid layer. In a temperature range where reproduction is performed by irradiation of reproducing light, the recording magnetic domain of the recording layer is transcribed onto the reproducing layer via the reproducing aid layer, and the information recorded in the recording layer is reproduced. The reproducing layer is a vertical magnetic film having a magnetic characteristic such that outside the reproducing temperature range, the recording magnetic domain in the reproducing layer transcribed from the recording layer shrinks and disappears.

Magneto-optical recording medium, and method for recording information in a recording layer

A process for producing an optical disk master, comprises the steps of forming a photoresist layer on a glass master, cutting the photoresist layer by projecting light beam onto the glass master having the photoresist layer thereon to expose the photoresist layer to light, developing the photoresist layer after the cutting step to form a hollow portion corresponding to the light-exposed portion, and carrying out an ion treatment by projecting ions onto the developed photoresist layer to decrease the thickness of the photoresist layer at the developed hollow portion to reach the prescribed depth by the ion-treatment.

Optical disk master, optical disk substrate stamper, process for production thereof, and magneto-optical recording medium

An optical information recording medium of the present invention includes: a substrate with at least one selected from the group consisting of a groove and a pit formed on one surface thereof; at least one information layer provided on the surfaces of the substrate, the information layer including at least one selected from the group consisting of a recording film and a reflective film; a resin layer provided on the information layer; and a light transmission layer provided on the resin layer. The resin layer includes a first resin film and a second resin film disposed in this order from the side of the light transmission layer, and when a water absorption rate of the first resin film is represented by Aand a water absorption rate of the second resin film is represented by A, Aand Asatisfy: A&#x3e;A. The first resin film and the second resin film may have a different flexural modulus of elasticity.

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Kyoto, Japan

Keiji Nishikiori