Patents by Inventor John F. N. Browne

John F. N. Browne has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Focus control system for optical information recorder or player
    Patent number: 4701603
    Abstract: A focus control system with a novel gain control circuit for continually varying the gain of the focus error signal based on the optical characteristics of the medium. As those optical characteristics change to decrease the amount of light available to the focus error detector, the gain of the focus error signal is increased so that the overall gain of the servo loop and the overall response of the servo to a focus error remains constant. This is accomplished by monitoring the optical characteristics of the medium which affect the focus error detector. In a multiple detector system, the outputs of all of the detectors are summed together. The resultant signal is a reflectivity or a transparency signal and is used in a novel circuit for controlling the servo gain.
    Type: Grant
    Filed: October 17, 1985
    Date of Patent: October 20, 1987
    Assignee: Optical Disc Corporation
    Inventors: W. Ray Dakin, John F. N. Browne