Optical system for tracking an information recording medium
Apparatus for correcting photodetector signals in a system for retrieving information from an optical recording medium Patent #: 4890272
ApplicationNo. 459966 filed on 01/02/1990
US Classes:369/44.37, Plural incident beams369/44.41Arithmetic operation using plural photodetectors
ExaminersPrimary: Black, Thomas G.
Attorney, Agent or Firm
Foreign Patent References
International ClassG11B 007/00
Foreign Application Priority Data1989-01-11 JP
AbstractIn an optical information-processing apparatus, retrieving and recording laser beams are focused on an optical disk in a recording mode. The retrieving and recording laser beams are reflected from the optical disk and are transferred by the objective lens. The transferred retrieving laser beam is spatially separated from the transferred recording laser beam and is incident on the photo-sensitive region of a photodetector the edge of photo-sensitive region is so arranged as to be separated at distance d2 from the recording laser beam when the objective lens is in focusing state. The distance d2 satisfies the following inequality:d2<m d1wherein d1 is a distance between the beam spot on the optical disk in the focusing state and m is a magnification of the optical system between the optical disk and the photodetector.