Patents Examined by Parpul Gupta
  • Patent number: 8363526
    Abstract: An optical pickup apparatus, which reads signals recorded on first and second signal recording layers of an optical disc, includes: a laser diode; an objective lens to condense a laser beam to the first and second signal recording layers; and a collimating lens disposed in a light path of the laser beam between the laser diode and the objective lens and configured to correct a spherical aberration by moving in a light axis direction of the laser beam, and the objective lens includes a bifocal lens and is configured such that a second focal point does not coincide in position with the second signal recording layer when a first focal point coincides in position with the first signal recording layer, and the first focal point does not coincide in position with the first signal recording layer when the second focal point coincides in position with the second signal recording layer.
    Type: Grant
    Filed: October 29, 2010
    Date of Patent: January 29, 2013
    Assignees: Sanyo Electric Co., Ltd., Sanyo Optec Design Co., Ltd.
    Inventors: Tohru Hotta, Ryoichi Kawasaki