Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Matsushita Electrical Industrial Co., Ltd.

Origin Electric Company, Limited

Matsushita Electric Industrial

Eiji Ohno

Noboru Yamada

Nobuo Akahira

Kenichi Nishiuchi

Kazuhiro Hayashi

Kenichi Nagata

Kazuya Hisada

Yoshitaka Sakaue

Ken'ichi Nagata

Hidemi Isomura

Shinya Abe

Masanari Mohri

Naoyasu Miyagawa

Morio Tomiyama

Kenji Narumi

Kazuo Inoue

Kunio Kimura

Keiji Nishikiori

Hiroyuki Ohta

Yuko Kawaguchi

Akihiro Moteki

Kazuhiro Higashimaru

Shigeaki Furukawa

Masahide Yokoyama

Hiroshi Hayata

Kazuhisa Ide

Hideo Matsumoto

Katsumi Kawahara

Kenzou Ishibashi

Norihisa Mino

Masahiro Nakamura

Rie Kojima

Tetsuya Akiyama

Hironobu Nishimura

Kazumi Yoshioka

Mayumi Uno

Toshiyuki Suemitsu

Masahiko Kotoyori

Eiichi Ito

Masatoshi Takao

Susumu Sanai

Yuuko Kawaguchi

Mayumi Otoba

Ken'ichi Nishiuchi

Noyasu Miyagawa

Seiichiro Mori

Masanari Mohrii

A transfer layer on a surface of a mold has a thickness distribution along the radius direction that the layer is thick in an inner round portion but is gradually thinner toward an outer round portion. An adhesive layer is formed between a surface of a signal substrate which bears a signal recording film and the mold which seats the transfer layer. The adhesive layer has a thickness distribution that the layer is thin in an inner round portion but is gradually thicker toward an outer round portion. Since the thickness distributions along the radius direction of the transfer layer and the adhesive layer are opposite to each other, the thickness distribution of an isolation layer which comprises the two layers is uniform.

Method of and apparatus for manufacturing multi-layer optical information recording medium

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

An optical recording medium includes a main-information area in which a metal reflection film is formed on a substrate where a row of pits is formed as main data, and a sub-information area in which is recorded medium identification information, which is used to identify the optical recording medium individually, by removing the metal reflection film partially and forming a plurality of reflection-film removed areas. Information is reproduced by irradiating the metal reflection film with a beam of light. In the sub-information area, a row of pits or a guide groove is formed on the substrate, and a track pitch of the row of pits or the guide groove is at least 0.24 &#x3bc;m wide and at most 0.45 &#x3bc;m wide.

Optical recording medium, manufacturing method for optical recording medium, and reproducing method for optical recording medium

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 of manufacturing an optical information recording medium to/from which signals can optically be recorded and reproduced. The recording medium includes a signal substrate (), a signal recording layer (), and a transparent cover layer () having a first transparent layer () and a second transparent layer (), which is harder than the first transparent layer (). Signals can be recorded and reproduced to and from the recording medium by a light transmitted to the signal recording layer through the transparent cover layer (). The first transparent layer is formed so as to have a first predetermined distribution of thickness. The second transparent layer is formed so as to have a second predetermined distribution of thickness to make the total thickness of the transparent cover layer () uniform. The first transparent layer () may be made of a plurality of thin laminated transparent layers.

Manufacturing method of optical information recording medium

Optical recording medium, optical recording medium manufacturing method, and optical recording medium reproducing method

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

A disc-shaped optical data recording medium has a signal recording layer for reading and/or writing data using light, and a 10 &#x3bc;m to 200 &#x3bc;m thick transparent protective layer disposed over the signal recording layer. The optical data recording medium includes a protrusion projecting from a surface of the transparent protective layer on a light-incidence surface side to which light is emitted to the signal recording layer. The protrusion is disposed in an area between a center hole and a clamping area where the optical data recording medium is held when reading and/or writing data in the signal recording layer.

Optical data recording disc with protrusion between clamping area and center hole

An optical recording medium is provided with: a first substrate having first pits on one face thereof; a first reflective layer that is formed on the face bearing the first pits of the first substrate in a manner so as to reflect lands and recesses of the first pits; a second substrate that is formed on the first reflective layer, with second pits being formed on a face on the side opposite to the first reflective layer; a second reflective layer that is formed on the face bearing the second pits of the second substrate in a manner so as to reflect lands and recesses of the second pits; and a cover layer formed on the second reflective layer. In this structure, the first pit depth dthat is a difference between lands and recesses of the first reflective layer, the wavelength &#x3bb; of signal-reproducing laser light and the refractive index nof the second substrate satisfy the following relational expressions: &#x3bb;/(5n)&#x2266;d&#x2266;&#x3bb;/(3n) and d&#x2260;&#x3bb;/(4n). Moreover, the second pit depth d, which is a difference between lands and recesses of the second reflective layer, the wavelength &#x3bb; of signal-reproducing laser light and the refractive index nof the cover layer satisfy the following relational expressions: &#x3bb;/(5n)&#x2266;d&#x2266;&#x3bb;/(3n) and d&#x2260;&#x3bb;/(4n).

Optical recording medium and process for producing the same

When a separation layer is formed using a stamper between a substrate and the stamper on a thick substrate, on the surface of which a rewritable recording multilayer film provided with signal guide grooves or pits and the signal guide grooves or pits are transferred from the stamper to the surface, variations in the thickness of the separation layer are produced due to unevenness of the distance between the stamper and the substrate. The surface of the kth signal recording layer of the kth signal substrate is shaped parallel to the surface with the guide grooves and pits of the (k&#x2212;1)th signal recording layer on the (k&#x2212;1)th stamper, a (k&#x2212;1)th separation layer is formed between the two and then the (k&#x2212;1)th stamper is peeled off. The distance between the surface with the guide grooves and pits of the (k&#x2212;1)th signal recording layer and the kth signal recording layer becomes uniform, and therefore the thickness of the (k&#x2212;1)th separation layer can be kept uniform.

Method of manufacturing multilayer optical information recording medium

Growing community of inventors

Hirakata, Japan

Eiji Ohno