Patents by Inventor Masaki Dojun

Masaki Dojun 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).

  • Patent number: 7012864
    Abstract: An optical disk recording apparatus operates on an optical disk having circular tracks which are provisionally written with an index signal used for securing a constant linear velocity of the optical disk from an innermost circular track to an outermost circular track, and records data along the circular tracks at different linear densities on different annular zones of the optical disk. In the apparatus, a disk drive section rotates the optical disk while synchronizing the index signal successively read from the rotated optical disk with a predetermined reference clock signal to thereby maintain the constant linear velocity of the circular tracks. A clock generating section multiples or divides the reference clock signal by different rates to generate different writing clock signals in correspondence to the different annular zones of the optical disk.
    Type: Grant
    Filed: June 16, 2004
    Date of Patent: March 14, 2006
    Assignee: Yamaha Corporation
    Inventors: Takuya Tamaru, Tatsuo Fushiki, Katsuichi Osakabe, Yusuke Konagai, Akira Usui, Kentaro Nomoto, Masaki Dojun, Kazuhiko Honda
  • Patent number: 6980495
    Abstract: In an optical recording apparatus having an optical pickup, a rotating section is provided for rotating an optical disk which is formed thereon with a guide groove to define a spiral track having a plurality of rounds. The optical pickup has a light source for generating an optical beam and a diffractive grating for diffracting the optical beam to form a main beam and a pair of sub beams opposite with each other relative to the main beam. The optical pickup is operable for irradiating the main beam to the spiral track with accompanying the pair of the sub beams along apposite sides of the spiral track. A servo section operates the optical pickup to enable the main beam to trace the spiral track based on a tracking error signal derived from return lights of the sub beams reflected back from the optical disk. A recording section modulates the main beam for recording of information onto the spiral track while the optical dick is rotated.
    Type: Grant
    Filed: June 20, 2003
    Date of Patent: December 27, 2005
    Assignee: Yamaha Corporation
    Inventors: Katsuichi Osakabe, Akira Usui, Shinji Aoshima, Hiromitsu Shibata, Masaki Dojun
  • Publication number: 20040228242
    Abstract: An optical disk recording apparatus operates on an optical disk having circular tracks which are provisionally written with an index signal used for securing a constant linear velocity of the optical disk from an innermost circular track to an outermost circular track, and records data along the circular tracks at different linear densities on different annular zones of the optical disk. In the apparatus, a disk drive section rotates the optical disk while synchronizing the index signal successively read from the rotated optical disk with a predetermined reference clock signal to thereby maintain the constant linear velocity of the circular tracks. A clock generating section multiples or divides the reference clock signal by different rates to generate different writing clock signals in correspondence to the different annular zones of the optical disk.
    Type: Application
    Filed: June 16, 2004
    Publication date: November 18, 2004
    Applicant: Yamaha Corporation
    Inventors: Takuya Tamaru, Tatsuo Fushiki, Katsuichi Osakabe, Yusuke Konagai, Akira Usui, Kentaro Nomoto, Masaki Dojun, Kazuhiko Honda
  • Publication number: 20040008593
    Abstract: In an optical recording apparatus having an optical pickup, a rotating section is provided for rotating an optical disk which is formed thereon with a guide groove to define a spiral track having a plurality of rounds. The optical pickup has a light source for generating an optical beam and a diffractive grating for diffracting the optical beam to form a main beam and a pair of sub beams opposite with each other relative to the main beam. The optical pickup is operable for irradiating the main beam to the spiral track with accompanying the pair of the sub beams along apposite sides of the spiral track. A servo section operates the optical pickup to enable the main beam to trace the spiral track based on a tracking error signal derived from return lights of the sub beams reflected back from the optical disk. A recording section modulates the main beam for recording of information onto the spiral track while the optical dick is rotated.
    Type: Application
    Filed: June 20, 2003
    Publication date: January 15, 2004
    Applicant: YAMAHA CORPORATION
    Inventors: Katsuichi Osakabe, Akira Usui, Shinji Aoshima, Hiromitsu Shibata, Masaki Dojun
  • Publication number: 20020105867
    Abstract: An optical disk recording apparatus operates on an optical disk having circular tracks which are provisionally written with an index signal used for securing a constant linear velocity of the optical disk from an innermost circular track to an outermost circular track, and records data along the circular tracks at different linear densities on different annular zones of the optical disk. In the apparatus, a disk drive section rotates the optical disk while synchronizing the index signal successively read from the rotated optical disk with a predetermined reference clock signal to thereby maintain the constant linear velocity of the circular tracks. A clock generating section multiples or divides the reference clock signal by different rates to generate different writing clock signals in correspondence to the different annular zones of the optical disk.
    Type: Application
    Filed: November 20, 2001
    Publication date: August 8, 2002
    Inventors: Takuya Tamaru, Tatsuo Fushiki, Katsuichi Osakabe, Yusuke Konagai, Akira Usui, Kentaro Nomoto, Masaki Dojun, Kazuhiko Honda