Patents by Inventor Tutomu Tabata

Tutomu Tabata 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).

  • Tracking adjustment using the sum of the maximum and minimum tracking error signals or the mean value of the sum
    Patent number: 5481526
    Abstract: An optical pickup emits a light beam onto a recording medium and outputs, in response to a reflection from the medium, a first and a second signal for controlling focusing servo control and tracking servo control, respectively. A signal generating section generates a focus error signal and a tracking error signal in response to the first and second signals, respectively. A driving section is responsive to the output of the signal generating section for outputting a first and a second drive current assigned to focusing and tracking, respectively. An actuator moves the pickup in a focusing direction and a tracking direction by the first and second drive currents, respectively. An adjusting section detects two values close to the maximum and minimum values of the tracking error signal at the start of the focusing servo control and adjusts the gain of the second signal on the basis of a difference between the detected values.
    Type: Grant
    Filed: June 28, 1994
    Date of Patent: January 2, 1996
    Assignee: Oki Electric Industrial Co., Ltd.
    Inventors: Shizuo Nagata, Yasuhiro Suzuki, Tutomu Tabata, Masahiro Takahashi
  • Adjustment of tracking servo and focusing servo in optical data recording/reproducing apparatus
    Patent number: 5351224
    Abstract: An optical pickup emits a light beam onto a recording medium and outputs, in response to a reflection from the medium, a first and a second signal for controlling focusing servo control and tracking servo control, respectively. A signal generating section generates a focus error signal and a tracking error signal in response to the first and second signals, respectively. A driving section is responsive to the output of the signal generating section for outputting a first and a second drive current assigned to focusing and tracking, respectively. An actuator moves the pickup in a focusing direction and a tracking direction by the first and second drive currents, respectively. An adjusting section detects two values close to the maximum and minimum values of the tracking error signal at the start of the focusing servo control and adjusts the gain of the second signal on the basis of a difference between the detected values.
    Type: Grant
    Filed: August 27, 1993
    Date of Patent: September 27, 1994
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Shizuo Nagata, Yasuhiro Suzuki, Tutomu Tabata, Masahiro Takahashi