Patents by Inventor Hideki Hirata

Hideki Hirata 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).

  • Publication number: 20070153671
    Abstract: An optical recording medium and a recording system for the same are provided, which can dissipate heat produced by a laser beam during recording operations to thereby increase the erasing power margin of the laser beam which allows the playback jitter value to take on a certain value or less. A recording system includes an optical recording medium and an optical recording apparatus. The optical recording medium has a reflective film, a second dielectric layer, a recording layer, a heat sink layer, and a light-transmitting layer, which are formed on a support substrate. The heat sink layer is made of a material having a certain range of thermal conductivity, e.g., alumina. The optical recording apparatus allows a laser beam of 450 nm or less in wavelength to be incident from the light-transmitting layer via a lens system having an objective lens with a numerical aperture of 0.7 or more.
    Type: Application
    Filed: March 2, 2007
    Publication date: July 5, 2007
    Applicant: TDK CORPORATION
    Inventors: Hiroyasu Inoue, Hideki Hirata
  • Patent number: 7231649
    Abstract: An optical recording medium includes a substrate, a first recording layer formed on the substrate and containing an element selected from the group consisting of Si, Sn and Ge as a primary component, and a second recording layer located in the vicinity of the first recording layer and containing Ag as a primary component, the optical recording medium being constituted to be irradiated by a laser beam projected onto the side opposite from the substrate. According to the thus constituted optical recording medium, it is possible to decrease a noise level and improve a C/N ratio in a reproduced signal.
    Type: Grant
    Filed: May 23, 2003
    Date of Patent: June 12, 2007
    Assignee: TDK Corporation
    Inventors: Masaki Aoshima, Hiroyasu Inoue, Koji Mishima, Hideki Hirata, Hajime Utsunomiya
  • Publication number: 20070121438
    Abstract: A method of testing an optical information medium and an optical information medium testing apparatus compare a voltage of a tracking error signal generated based on return light from the optical information medium received by an optical pickup and a reference voltage set in advance and judge that a fault is present on the optical information medium when the voltage of the tracking error signal is equal to or greater than the reference voltage.
    Type: Application
    Filed: November 15, 2006
    Publication date: May 31, 2007
    Applicant: TDK CORPORATION
    Inventors: Takashi YAMADA, Tatsuya KATO, Tomoki USHIDA, Hideki HIRATA
  • Patent number: 7224663
    Abstract: It is an object of the present invention to provide a method of recording information to an optical recording medium that is suited to achieving high data transfer rates. The optical recording medium according to the present invention comprises a method of recording information to an optical recording medium where information is recorded by forming a plurality of recording marks selected from a group consisting of several types of recording marks each with different lengths, wherein: the cooling interval when forming the shortest recording mark contained within said group is set shorter than the cooling interval when forming the other recording marks contained in the group. Thus, even in the case that one clock period (T) is shortened to achieve high transfer rates, a high erase efficiency can be maintained when overwriting data.
    Type: Grant
    Filed: September 5, 2002
    Date of Patent: May 29, 2007
    Assignee: TDK Corporation
    Inventors: Tatsuya Kato, Hiroshi Shingai, Hideki Hirata
  • Patent number: 7203150
    Abstract: An optical recording medium and a recording system for the same are provided, which can dissipate heat produced by a laser beam during recording operations to thereby increase the erasing power margin of the laser beam which allows the playback jitter value to take on a certain value or less. A recording system 1 includes an optical recording medium 10 and an optical recording apparatus 30. The optical recording medium 10 has a reflective film 16, a second dielectric layer 18, a recording layer 20, a heat sink layer 24, and a light-transmitting layer 26, which are formed on a support substrate 12. The heat sink layer 24 is made of a material having a certain range of thermal conductivity, e.g., alumina. The optical recording apparatus 30 allows a laser beam of 450 nm or less in wavelength to be incident from the light-transmitting layer 26 via a lens system having an objective lens with a numerical aperture of 0.7 or more.
    Type: Grant
    Filed: September 24, 2002
    Date of Patent: April 10, 2007
    Assignee: TDK Corporation
    Inventors: Hiroyasu Inoue, Hideki Hirata
  • Patent number: 7200084
    Abstract: 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.
    Type: Grant
    Filed: April 18, 2003
    Date of Patent: April 3, 2007
    Assignee: TDK Corporation
    Inventors: Takashi Namioka, Yasufumi Takasugi, Kazuo Fukunaga, Toshikazu Hosobuchi, Giichi Shibuya, Hideki Hirata, Kazuki Suzawa
  • Patent number: 7197005
    Abstract: In an optical recording medium including a grooved light-transparent substrate, a phase change recording layer, a dielectric layer and a reflective layer, recording is carried out by irradiating a laser beam to the recording layer through an objective lens in an optical system. The recording is carried out in a groove recording mode under the conditions: 0.48?PT/(?/NA)?0.74, and PT?0.50 ?m wherein ? is a laser beam wavelength, NA is an objective lens numerical aperture, and PT is a track pitch, thereby forming a recorded mark having opposite ends extending out of the groove. This enables high density recording and increases the data transfer rate of a phase change optical recording medium.
    Type: Grant
    Filed: October 9, 2001
    Date of Patent: March 27, 2007
    Assignee: TDK Corporation
    Inventors: Tatsuya Kato, Hideki Hirata, Hajime Utsunomiya, Hiroyasu Inoue
  • Patent number: 7182990
    Abstract: An optical information recording medium which makes it possible to reduce the noise level and improve the C/N ratio. An optical information recording medium has a recording layer formed on a substrate, for having a laser beam irradiated thereto for recording and reproducing record data. The recording layer includes a first sub-recording film and a second sub-recording film. The first sub-recording film is formed of a first material containing Si as a main component. The second sub-recording film is formed of a second material containing Zn as a main component and having Al added thereto, and disposed in the vicinity of the first recording film. The laser beam is irradiated to the recording layer via a light transmitting layer formed in a manner covering the recording layer.
    Type: Grant
    Filed: July 22, 2004
    Date of Patent: February 27, 2007
    Assignee: TDK Corporation
    Inventors: Hiroyasu Inoue, Koji Mishima, Masaki Aoshima, Hideki Hirata, Hajime Utsunomiya
  • Patent number: 7177254
    Abstract: An optical recording method that performs recording by irradiating optical recording media with laser beam modulated in intensity based on a write waveform is provided. The write waveform has a plurality of write pulse blocks for forming write marks, and each write pulse block has at least one type of upward pulse. In the event that the width of said upward pulse is so narrow that the laser beam intensity corresponding to the peak intensity of that upward pulse cannot be obtained, the peak intensity of that upward pulse is increased so that, in said laser beam, the beam intensity it should have or a value close thereto is obtained. Thereby, good recording and playback characteristics can be obtained even when recording at a high transfer rate.
    Type: Grant
    Filed: March 27, 2002
    Date of Patent: February 13, 2007
    Assignee: TDK Corporation
    Inventors: Tatsuya Kato, Hajime Utsunomiya, Hideki Hirata
  • Patent number: 7173893
    Abstract: It is an object of the present invention to provide a method of recording information to an optical recording medium that is suited to achieving high data transfer rates. The optical recording medium according to the present invention comprises a method of recording information to an optical recording medium where information is recorded by forming on the optical recording medium a plurality of recording marks selected from a group consisting of several types of recording marks each with different lengths, wherein a first recording mark and a second recording mark contained within said group are formed with the number of pulses and the pulse spacing in the laser beam set substantially equal to each other. Thus, even in the case that one clock period (T) is shortened to achieve high transfer rates, recording marks with good shapes can be formed. In addition, control is simplified and it is possible to reduce the cost of a drive to which the present invention is applied.
    Type: Grant
    Filed: September 5, 2002
    Date of Patent: February 6, 2007
    Assignee: TDK Corporation
    Inventors: Tatsuya Kato, Hiroshi Shingai, Hideki Hirata
  • Patent number: 7166347
    Abstract: An optical information recording medium which makes it possible to reduce the noise level, improve the C/N ratio and store record data for a long time period. An optical information recording medium has a recording layer formed on a substrate, for having a laser beam irradiated thereto for recording and reproduction of record data. The recording layer includes a first sub-recording film and a second sub-recording film. The first sub-recording film is formed of a first material containing Si as the main component. The second sub-recording film is formed of a second material containing Al as the main component and having Cu added thereto, and disposed in the vicinity of the first recording film. The laser beam is irradiated to the recording layer via a light transmitting layer formed in a manner covering the recording layer side.
    Type: Grant
    Filed: August 24, 2004
    Date of Patent: January 23, 2007
    Assignee: TDK Corporation
    Inventors: Hiroyasu Inoue, Koji Mishima, Masaki Aoshima, Hideki Hirata, Hajime Utsunomiya
  • Patent number: 7167440
    Abstract: An optical information recording medium which makes it possible to reduce the noise level, improve the C/N ratio and store record data for a long time period. An optical information recording medium has a recording layer formed on a substrate, for having a laser beam irradiated thereto for recording and reproduction of record data. The recording layer includes a first sub-recording film and a second sub-recording film. The first sub-recording film is formed of a first material containing Si as the main component. The second sub-recording film is formed of a second material containing Al as the main component and having Ti added thereto, and disposed in the vicinity of the first recording film. The laser beam is irradiated to the recording layer via a light transmitting layer formed in a manner covering the recording layer side.
    Type: Grant
    Filed: August 24, 2004
    Date of Patent: January 23, 2007
    Assignee: TDK Corporation
    Inventors: Hiroyasu Inoue, Koji Mishima, Masaki Aoshima, Hideki Hirata, Hajime Utsunomiya
  • Patent number: 7160597
    Abstract: An optical information recording medium which makes it possible to reduce the noise level and improve the C/N ratio and store record data for a long time period. An optical information recording medium has a recording layer formed on a substrate, for having a laser beam irradiated thereto for recording and reproduction of record data. The recording layer includes a first sub-recording film and a second sub-recording film. The first sub-recording film is formed of a first material containing Si as a main component. The second sub-recording film is formed of a second material containing Al as a main component and having Mg added thereto, and disposed in the vicinity of the first recording film. The laser beam is irradiated to the recording layer via a light transmitting layer formed in a manner covering the recording layer.
    Type: Grant
    Filed: July 22, 2004
    Date of Patent: January 9, 2007
    Assignee: TDK Corporation
    Inventors: Hiroyasu Inoue, Koji Mishima, Masaki Aoshima, Hideki Hirata, Hajime Utsunomiya
  • Patent number: 7158459
    Abstract: 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.
    Type: Grant
    Filed: April 25, 2003
    Date of Patent: January 2, 2007
    Assignee: TDK Corporation
    Inventors: Toshikazu Hosobuchi, Takashi Namioka, Yasufumi Takasugi, Kazuo Fukunaga, Giichi Shibuya, Hideki Hirata, Kazuki Suzawa
  • Patent number: 7157128
    Abstract: An optical information recording medium which is capable of performing high-density recording of record data, and storing the recorded data for a long time period such that the recorded data can be normally reproduced during the long time period. An optical information recording medium has a recording layer formed on a substrate, for having a laser beam irradiated thereto for recording and reproduction of record data. The recording layer includes a first sub-recording film and a second sub-recording film. The first sub-recording film is formed of a first material containing Si as the main component. The second sub-recording film is formed of a second material containing Cu as the main component and having Si added thereto, and disposed in the vicinity of the first recording film.
    Type: Grant
    Filed: July 22, 2004
    Date of Patent: January 2, 2007
    Assignee: TDK Corporation
    Inventors: Hiroyasu Inoue, Koji Mishima, Masaki Aoshima, Hideki Hirata, Hajime Utsunomiya
  • Patent number: 7154836
    Abstract: An optical recording/reproducing method and an optical recording medium capable of performing excellent optical recording with a simple structure in a recording layer made of environmentally friendly materials. The optical recording medium has a recording layer on a substrate. The recording layer has a pair of dielectric layers of which states are altered by a laser beam that is an energy beam of which intensity is modulated according to information to be recorded. This recording layer also has a assisting material layer sandwiched by these dielectric layers. The assisting material layer includes an element selected from Sn, Ti, Si, Bi, Ge, and C as a principle component, while the dielectric material as a base material for the dielectric layers is any one of ZnS, SiO2, AlN, and Ta2O5.
    Type: Grant
    Filed: May 29, 2003
    Date of Patent: December 26, 2006
    Assignee: TDK Corporation
    Inventors: Hiroyasu Inoue, Koji Mishima, Masaki Aoshima, Hideki Hirata, Hajime Utsunomiya, Hitoshi Arai, Yoshitomo Tanaka
  • Patent number: 7141288
    Abstract: An optical information recording medium which is capable of performing high-density recording of record data, and storing the recorded data for a long time period such that the recorded data can be normally reproduced during the long time period. An optical information recording medium has a recording layer formed on a substrate, for having a laser beam irradiated thereto for recording and reproduction of record data. The recording layer includes a first sub-recording film and a second sub-recording film. The first sub-recording film is formed of a first material containing Si as the main component. The second sub-recording film is formed of a second material containing Cu as the main component and having Mg added thereto, and disposed in the vicinity of the first recording film.
    Type: Grant
    Filed: August 24, 2004
    Date of Patent: November 28, 2006
    Assignee: TDK Corporation
    Inventors: Hiroyasu Inoue, Koji Mishima, Masaki Aoshima, Hideki Hirata, Hajime Utsunomiya
  • Patent number: 7141289
    Abstract: An optical information recording medium which is capable of performing high-density recording of record data, and storing the recorded data for a long time period such that the recorded data can be normally reproduced during the long time period. An optical information recording medium has a recording layer formed on a substrate, for having a laser beam irradiated thereto for recording and reproduction of record data. The recording layer includes a first sub-recording film and a second sub-recording film. The first sub-recording film is formed of a first material containing Si as the main component. The second sub-recording film is formed of a second material containing Cu as the main component and having Zn added thereto, and disposed in the vicinity of the first recording film.
    Type: Grant
    Filed: August 24, 2004
    Date of Patent: November 28, 2006
    Assignee: TDK Corporation
    Inventors: Hiroyasu Inoue, Koji Mishima, Masaki Aoshima, Hideki Hirata, Hajime Utsunomiya
  • Patent number: 7136343
    Abstract: An optical recording/reproducing method and an optical recording medium capable of performing excellent optical recording with a simple structure in a recording layer made of environmentally friendly materials. The optical recording medium has a recording layer formed on a substrate and made of a mixture of a recording assist material and a dielectric material. A laser beam of which intensity is modulated in accordance with information to be recorded is irradiated onto this recording layer to cause a state change in the recording assist material and/or the dielectric material. The information can be recorded by changing optical characteristics thereof such as reflectivity. The recording assist material includes an element selected from Sn, Ti, Si, Bi, Ge, and C as a principle component, while the dielectric material as a base material for the dielectric layers is at least one of ZnS, SiO2, AlN, and Ta2O5.
    Type: Grant
    Filed: May 29, 2003
    Date of Patent: November 14, 2006
    Assignee: TDK Corporation
    Inventors: Hiroyasu Inoue, Koji Mishima, Masaki Aoshima, Hideki Hirata, Hajime Utsunomiya, Hitoshi Arai, Yoshitomo Tanaka
  • Patent number: 7085213
    Abstract: 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.
    Type: Grant
    Filed: April 23, 2003
    Date of Patent: August 1, 2006
    Assignee: TDK Corporation
    Inventors: Kazuo Fukunaga, Toshikazu Hosobuchi, Takashi Namioka, Yasufumi Takasugi, Giichi Shibuya, Hideki Hirata, Kazuki Suzawa, Tsutomu Kotani