[n: For Focusing And Tracking (g9b/7.083 To G9b/7.086 Take Precedence)] [c0408] {g11b 7/09d3} Patents (Class G9B/7.082)
  • Publication number: 20110299375
    Abstract: In a small-sized optical pickup device for enabling to obtain a stable servo-signal, as well as, a focus error signal and a tracking error signal, without receiving ill influences of stray lights from other layers, when recording/reproducing a multi-layer optical disc, a reflection light from the multi-layer optical disc is divided into plural numbers of regions by a diffraction grating. And, it is divided into at least four (4) regions, by a division line in the tangential direction of the optical disc and a division line in the radial direction thereof. Light receiving parts, for detecting either one of grating diffraction lights, i.e.
    Type: Application
    Filed: April 1, 2011
    Publication date: December 8, 2011
    Inventors: Kazuyoshi YAMAZAKI, Daisuke Tomita