Patents by Inventor Keith Raper

Keith Raper 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).

  • Laser diode supply circuit
    Patent number: 5199039
    Abstract: A voltage source is connected to a laser diode via a supply circuit and a control circuit serving to control current through the laser diode. The control circuit includes a transistor which is switched into conduction on the application of a threshold valued voltage. A light sensitive diode is optically coupled to the laser diode and is adapted to apply a control voltage to the transistor switch which is related to the optical power output of the laser diode, such that when the control voltage exceeds a predetermined threshold value, the transistor is rendered conductive to control current through the laser diode.
    Type: Grant
    Filed: July 22, 1991
    Date of Patent: March 30, 1993
    Assignee: Imatronic Limited
    Inventor: Keith Raper