Optical information-processing apparatus
Patent 5105407 Issued on April 14, 1992. Estimated Expiration Date: 
January 2, 2010. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
January 2, 2010. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesOptical 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 InventorApplicationNo. 459966 filed on 01/02/1990US Classes:369/44.37, Plural incident beams369/44.41Arithmetic operation using plural photodetectorsExaminersPrimary: Black, Thomas G.Attorney, Agent or FirmForeign Patent References
International ClassG11B 007/00Foreign Application Priority Data1989-01-11 JPAbstractIn 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.Other References
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