Patents by Inventor Naomasa Nakamura

Naomasa Nakamura has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • WRITE-ONCE INFORMATION RECORDING MEDIUM AND DISK APPARATUS
    Publication number: 20090196159
    Abstract: According to one embodiment, a write-once information recording medium includes a transparent resin substrate having concentric or spiral grooves and lands, and a recording film formed on the grooves and lands of the transparent resin substrate, wherein the recording film includes an organic dye layer containing a metal complex monomer and a metal complex polymer, a recording mark is formed in the organic dye layer by emission of a short-wavelength laser beam, and a light reflectance of the recording mark formed by emission of the short-wavelength laser beam is higher than that before emission of the short-wavelength laser beam, and the grooves wobble within a predetermined amplitude range.
    Type: Application
    Filed: January 29, 2009
    Publication date: August 6, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Seiji Morita, Koji Takazawa, Kazuyo Umezawa, Naoki Morishita, Naomasa Nakamura
  • INFORMATION RECORDING MEDIUM
    Publication number: 20090196157
    Abstract: According to one embodiment, an information recording medium includes a substrate, a phase-change recording layer formed on the substrate, and a reflecting layer formed on the phase-change recording layer. The phase-change recording layer contains tellurium and antimony or bismuth as main components, has a crystallization rate of 2 to 10 ns, and forms a recording mark by changing its crystal state when irradiated with a light pulse having a half-width of 200 ps to 1 ns.
    Type: Application
    Filed: January 8, 2009
    Publication date: August 6, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Naomasa NAKAMURA, Keiichiro YUSU
  • Optical disc, optical disc manufacturing method, and optical disc apparatus
    Patent number: 7570566
    Abstract: According to one embodiment, an optical disc is the following the distance between a light incidence plane and the first recording layer is a minimum of 550 ?m. The distance between the first and the third recording layer is a maximum of 72 ?m. The distance between the second and the third recording layer is a minimum of 15 ?m. The distance between the first and the second recording layer is about 31 to 40 ?m. The reflectivities of the first and the second recording layer with respect to the first laser beam range from 18 to 27%, and the ratio therebetween is about 1.1 or less. The reflectivity of the third recording layer is below about 6%. The areal recording density of the third recording layer is three times or more as high as that of the first recording layer and the second recording layer.
    Type: Grant
    Filed: August 16, 2006
    Date of Patent: August 4, 2009
    Assignees: Kabushiki Kaisha Toshiba, Memory-Tech Corporation
    Inventors: Toshihiro Sugaya, Masato Otsuka, Naomasa Nakamura, Nobuhisa Yoshida, Hisashi Yamada
  • INFORMATION RECORDING MEDIUM AND DISK APPARATUS USING THE MEDIUM
    Publication number: 20090092035
    Abstract: According to one embodiment, an information recording medium includes a transparent resin substrate having concentric grooves and concentric lands or a spiral groove and spiral land, and a recording layer formed on the groove and land, and capable of recording and reproducing information by using a semiconductor laser of 450 nm or less. When reproducing recorded information, the information recording medium satisfies the following formula (1) 0.87?M4×/M1×?1.
    Type: Application
    Filed: September 25, 2008
    Publication date: April 9, 2009
    Inventors: Kazuyo Umezawa, Seiji Morita, Koji Takazawa, Naomasa Nakamura, Naoki Morishita
  • Phase-change optical recording media
    Patent number: 7510753
    Abstract: A Phase-change optical recording media includes a recording film that causes reversible phase-change between a crystalline phase and an amorphous phase on irradiation with light, and an interface film formed in contact with at least one surface of the recording film and containing Hf (hafnium), O (oxygen) and N (nitrogen).
    Type: Grant
    Filed: September 27, 2005
    Date of Patent: March 31, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tsukasa Nakai, Sumio Ashida, Keiichiro Yusu, Noritake Oomachi, Naomasa Nakamura
  • INFORMATION RECORDING MEDIUM
    Publication number: 20090022931
    Abstract: According to one embodiment, an information recording medium including a recording film using an organic recording material recorded by recording light having a wavelength of 405 nm and an organic recording material whose light reflection quantity varies by reproducing light having a wavelength of 650 nm for a recording layer and an optical reflection layer and a land sandwiched between a pre-groove having an irregular shape and an adjoining pre-groove is provided on an interface between the recording layer and the optical reflection layer.
    Type: Application
    Filed: July 18, 2008
    Publication date: January 22, 2009
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Seiji MORITA, Koji TAKAZAWA, Kazuyo UMEZAWA, Naoki MORISHITA, Naomasa NAKAMURA
  • Optical disc, optical disc apparatus, optical disk reproducing method, and digital work publication
    Patent number: 7477592
    Abstract: An optical disc of this invention is configured to be capable of dealing with both information in HD DVD and information in DVD.
    Type: Grant
    Filed: December 5, 2005
    Date of Patent: January 13, 2009
    Assignees: Kabushiki Kaisha Toshiba, Memory-Tech Corporation
    Inventors: Toshihiro Sugaya, Naomasa Nakamura, Nobuhisa Yoshida, Masato Otsuka
  • INFORMATION RECORDING MEDIUM AND DISK APPARATUS USING THE MEDIUM
    Publication number: 20080310280
    Abstract: According to one embodiment, an information recording medium has a plurality of recording layers, and records and reproduces information by using a semiconductor layer of 450 nm or less. When reproducing information, letting x be the frequency of repetitive recording of a shortest mark length and shortest space length of the information, the ratio of the value of a highest level to the value of a level at x/190 of a sum signal detected within the frequency range of x/3240 to x/190 is lower than 32 dB, or the ratio of the average value of the amplitudes of signals of repetitive recording of the shortest mark length and shortest space length to the value of the highest level within the frequency range of x/3240 to x/190 is higher than 10 dB.
    Type: Application
    Filed: June 17, 2008
    Publication date: December 18, 2008
    Inventors: Kazuyo Umezawa, Seiji Morita, Koji Takazawa, Naomasa Nakamura, Naoki Morishita, Shinichi Katsuda
  • INFORMATION RECORDING MEDIUM, INFORMATION RECORDING METHOD, AND INFORMATION REPRODUCING METHOD
    Publication number: 20080304401
    Abstract: According to one embodiment, an optical information recording medium includes pre-grooves with an irregular shape and lands each of which is sandwiched between the pre-grooves adjacent to each other, where the pre-grooves and lands are defined on an interface between a recording layer and a light reflection layer in a recording film, where the recording film includes a light reflectivity that enables reproduction with light of 650±5 nm, the recording layer includes a recording sensitivity with respect to light by a wavelength shorter than 650±5 nm, and a recording mark can be formed on the pre-groove by using light with a wavelength shorter than 650±5 nm.
    Type: Application
    Filed: January 4, 2008
    Publication date: December 11, 2008
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hideo Ando, Hisashi Yamada, Seiji Morita, Koji Takazawa, Naomasa Nakamura, Kazuo Watabe, Nobuaki Kaji, Masahiko Mawatari, Nobuhisa Yoshida, Koichi Nagai
  • Information recording medium and its manufacturing method
    Patent number: 7455951
    Abstract: A phase change recording medium comprising an as-deposited first recording layer configured to undergo a reversible phase change between an amorphous state and a crystalline state due to light irradiation and thereby change an optical characteristic. The as-deposited first recording layer includes a plurality of fine nuclei having an average size of 0.5 nm to 4 nm in the amorphous state.
    Type: Grant
    Filed: March 27, 2006
    Date of Patent: November 25, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Katsutaro Ichihara, Sumio Ashida, Keiichiro Yusu, Toshihiko Nagase, Naomasa Nakamura
  • INFORMATION RECORDING MEDIUM
    Publication number: 20080247304
    Abstract: According to one embodiment, when recording information by using a semiconductor laser at 450 nm or less, an information recording medium satisfies 9.5×10?8??/(X*NA)?4.6×10?8 (where X is the linear recording velocity, ? is the laser wavelength, and NA is the numerical aperture).
    Type: Application
    Filed: January 28, 2008
    Publication date: October 9, 2008
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kazuyo Umezawa, Seiji Morita, Koji Takazawa, Hideo Ando, Naomasa Nakamura, Naoki Morishita
  • OPTICAL DISC AND OPTICAL DISC DEVICE
    Publication number: 20080151728
    Abstract: An optical disc is provided which realizes desired optical properties, which has a transmissive reflection layer causing no deformation and the like of minute convex pits, and which can realize superior reproduction properties even when high density recording is performed. The above optical disc has at least three information layers independent with respect to a light incident surface, and a reflection layer formed on an information layer other than the layers most close to and most far from the light incident surface has a thickness of 5 to 20 nm and has a refractive index of 3.0 or more and an extinction coefficient of 0.6 or less with respect to the wavelength of incident laser light. This reflection layer is preferably composed of at least one material selected from the group consisting of Si, a SiCr alloy, a SiNb alloy, a SiW alloy, and SiC.
    Type: Application
    Filed: December 19, 2007
    Publication date: June 26, 2008
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Keiichiro Yusu, Naomasa Nakamura, Nobuhisa Yoshida, Yasuaki Ootera
  • OPTICAL DISK AND OPTICAL DISK APPARATUS USING THE SAME
    Publication number: 20080151727
    Abstract: According to one embodiment, in a single-sided, triple-layered optical disk, at least a first reflecting layer on the light incident side is made of silicon or a silicon compound, and has a recording density lower than those of second and third reflecting layers.
    Type: Application
    Filed: December 17, 2007
    Publication date: June 26, 2008
    Inventors: Naomasa Nakamura, Nobuhisa Yoshida, Yasuaki Ootera
  • Phase-change optical recording medium
    Patent number: 7357969
    Abstract: A phase-change optical recording medium has a first information layer including a phase-change optical recording film arranged in a position close to the light incident side, a second information layer including another phase-change optical recording film arranged in a position remote from the light incident side and an interlayer separating film arranged between the first information layer and the second information layer, in which at least one of the first information layer and the second information layer includes a noise reduction film in contact with the interlayer separating film. The noise reduction film is formed of SiOx (1?x?2) or SiOC.
    Type: Grant
    Filed: October 29, 2004
    Date of Patent: April 15, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tsukasa Nakai, Sumio Ashida, Keiichiro Yusu, Takayuki Tsukamoto, Noritake Oomachi, Naomasa Nakamura, Urara Ichihara, legal representative, Katsutaro Ichihara
  • Optical Disc, Optical Disc Device, and Optical Disc Reproducing Method
    Publication number: 20080056114
    Abstract: According to one embodiment, disclosed is an optical disc in which information is recorded by a pit pattern and which includes a reflection membrane. When concavities and convexities of the pits are opposite to those of a usual case, the reflection membrane is formed on the pits in the form of a two-layer membrane of silver or a silver alloy and aluminum or an aluminum alloy. The reflection membrane is formed with a two-layer structure including a first layer and a second layer different from the first layer. The material of the first layer is aluminum, an aluminum alloy or aluminum oxide. The second layer contacts the first layer and its material is silver or a silver alloy.
    Type: Application
    Filed: August 30, 2007
    Publication date: March 6, 2008
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yasuaki Ootera, Nobuhisa Yoshida, Naomasa Nakamura
  • Phase-change optical recording medium
    Patent number: 7335459
    Abstract: A phase-change optical recording medium includes a phase-change optical recording film that permits reversible phase change between a crystalline phase and an amorphous phase upon irradiation with light, and an interface film formed of hafnium oxide, or a mixture of hafnium oxide and at least one oxide selected from the group consisting of cerium oxide, titanium oxide and zirconium oxide, and formed in contact with at least one surface of the phase-change optical recording film.
    Type: Grant
    Filed: November 21, 2003
    Date of Patent: February 26, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Sumio Ashida, Takayuki Tsukamoto, Keiichiro Yusu, Katsutaro Ichihara, Noritake Ohmachi, Naomasa Nakamura, Nobuhisa Yoshida
  • INFORMATION RECORDING MEDIUM AND DISC APPARATUS
    Publication number: 20080013440
    Abstract: According to one embodiment, an information recording medium has two or more recording layers, the track pitch falls within the range from 250 to 500 nm, and the half maximum full-width of the groove of the substrate falls within the range from 47.5% to 72.5%.
    Type: Application
    Filed: June 26, 2007
    Publication date: January 17, 2008
    Inventors: Ryosuke YAMAMOTO, Masaaki Matsumaru, Kazuyo Umezawa, Koji Takazawa, Seiji Morita, Naomasa Nakamura, Hideo Ando
  • WRITE ONCE INFORMATION RECORDING MEDIUM AND DISK APPARATUS
    Publication number: 20080002560
    Abstract: According to one embodiment, a first recording film, interlayer, and second recording film are formed on a transparent resin substrate having a groove and land. A recording mark is formed by irradiation with a short-wavelength laser beam. The light reflectance of the recording mark formed by irradiation with the short-wavelength laser beam is higher than a light reflectance before irradiation with the short-wavelength laser beam. The first recording film has a first read-only recording mark recorded by a three-dimensional pit. The second recording film has a second read-only recording mark recorded by a three-dimensional pit. The reflectances of the pits of the first and second recording layers are 4.2% to 8.4%, or the pit width of the second recording film is larger than that of the first recording layer.
    Type: Application
    Filed: June 25, 2007
    Publication date: January 3, 2008
    Inventors: Seiji Morita, Koji Takazawa, Kazuyo Umezawa, Naoki Morishita, Naomasa Nakamura
  • INFORMATION RECORDING MEDIUM AND DISC APPARATUS
    Publication number: 20080002561
    Abstract: According to one embodiment, in an information recording medium in which letting H1 (nm) a groove depth of a first substrate on which a first recording layer is formed, H2 (nm) a groove depth of a second substrate on which a second recording layer is formed, H11 (nm) a thickness of a first dye layer at a land area, H12 (nm) a thickness of the first dye layer at a groove bottom area, H21 (nm) a thickness of a second dye layer at a land area, and H22 (nm) a thickness of the second dye layer at a groove bottom area, the groove depth H1 of the first substrate and the groove depth H2 of the second substrate satisfy |H11?H12|=?, |H21?H22|=?, ?/8n?H1????/3n, and ?/8n?H2????/3n.
    Type: Application
    Filed: June 25, 2007
    Publication date: January 3, 2008
    Inventors: Masaaki MATSUMARU, Ryosuke YAMAMOTO, Hideo ANDO, Naomasa NAKAMURA, Koji TAKAZAWA, Kazuyo UMEZAWA, Seiji MORITA, Noritake OOMACHI
  • INFORMATION RECORDING MEDIUM AND DISC APPARATUS
    Publication number: 20080002558
    Abstract: According to one embodiment, an information recording medium has a first substrate, first recording layer, second recording layer, and second substrate. The first recording layer has a first dye layer and first reflecting layer from the light incidence side. The second recording layer has a second dye layer and second reflecting layer from the light incidence side. The thickness of the second dye layer is larger than that of the first dye layer.
    Type: Application
    Filed: June 25, 2007
    Publication date: January 3, 2008
    Inventors: Koji TAKAZAWA, Seiji Morita, Kazuyo Umezawa, Naoki Morishita, Yasuaki Ootera, Hideo Ando, Naomasa Nakamura