Patents Assigned to Hitachi-LG Data Storage Co., Ltd.
  • Patent number: 7406014
    Abstract: The invention relates to a disc discriminating method and an optical disc information reproducing apparatus wherein DVD-RAM which is DVD-RAM1 or DVD-RAM2 and DVDRW which is DVD-RW or DVD+RW which cannot be respectively determined based upon distance from the surface of a disc to the recording face, the number of recording faces and the reflectance can be discriminated. In case an optical disc is DVD-RAM or DVDRW, the amplitude of a push-pull tracking error signal is measured by a microcomputer in a state in which servo control is executed based upon a focus error signal. Determination is performed based upon the amplitude of the push-pull tracking error signal, when the amplitude of the push-pull tracking error signal is larger than a predetermined value, the optical disc is judged as DVD-RAM and when the amplitude is smaller than the predetermined value, the optical disc is judged as DVDRW.
    Type: Grant
    Filed: October 6, 2004
    Date of Patent: July 29, 2008
    Assignees: Hitachi, Ltd., Hitachi-LG Data Storage Co., Ltd.
    Inventors: Kazuhiko Ono, Hirotoshi Fukuda, Takeshi Ikeda
  • Patent number: 6822936
    Abstract: The invention relates to a disc discriminating method and an optical disc information reproducing apparatus wherein DVD-RAM which is DVD-RAM1 or DVD-RAM2 and DVDRW which is DVD−RW or DVD+RW which cannot be respectively determined based upon distance from the surface of a disc to the recording face, the number of recording faces and the reflectance can be discriminated. In case an optical disc is DVD-RAM or DVDRW, the amplitude of a push-pull tracking error signal is measured by a microcomputer in a state in which servo control is executed based upon a focus error signal. Determination is performed based upon the amplitude of the push-pull tracking error signal, when the amplitude of the push-pull tracking error signal is larger than a predetermined value, the optical disc is judged as DVD-RAM and when the amplitude is smaller than the predetermined value, the optical disc is judged as DVDRW.
    Type: Grant
    Filed: July 20, 2001
    Date of Patent: November 23, 2004
    Assignees: Hitachi, Ltd., Hitachi-LG Data Storage Co., Ltd.
    Inventors: Kazuhiko Ono, Hirotoshi Fukuda, Takeshi Ikeda