Patents Represented by Law Firm Dickstein Shapiro Morin & Oshisky LLP
  • Patent number: 6072579
    Abstract: An optical pickup apparatus includes first and second light sources which selectively emit one of first and second light beams, the first and second light beams being different in wavelength, the wavelengths of the first and second light beams being appropriate for accessing first and second optical disks respectively. A coupling lens converts a corresponding one of the first and second light beams into a collimated beam. An objective lens forms a light spot on a corresponding one of the first and second optical disks by focusing the collimated beam. A holographic optical element receives a reflection beam of the light spot from one of the first and second optical disks and provides holographic effects on the reflection beam so as to diffract the reflection beam in predetermined diffracting directions depending on the wavelength of the reflection beam.
    Type: Grant
    Filed: August 24, 1999
    Date of Patent: June 6, 2000
    Assignee: Ricoh Company, Ltd.
    Inventor: Hiroyoshi Funato