Patents by Inventor Stuart Douglas

Stuart Douglas 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).

  • Patent number: 5889802
    Abstract: A bias controller for a semiconductor laser, for example, a laser having an light output which exhibits a threshold at a threshold value of an input drive current, is disclosed. The bias controller includes a test signal generator arranged to generate a low frequency test signal which is the superposition of a modulated control signal on a DC bias signal which is applied to the laser as a drive current superimposed on a high frequency data signal. A detector is arranged to determine the value of either the third harmonic component, or the second harmonic component, of the light output of the laser. A control means is arranged to control the DC bias current to have a value close to the threshold value by maintaining the detected value of the harmonic component of the light output of the laser near to a predetermined value.
    Type: Grant
    Filed: March 27, 1997
    Date of Patent: March 30, 1999
    Assignee: Hewlett-Packard Company
    Inventor: Stuart Douglas Walker
  • Patent number: 5653195
    Abstract: In an animal stall, a brisket board extends along the front end portion of the floor, and a keeper board extends along the rear portion of the floor. An animal mattress is disposed on the floor between the brisket board and the keeper board, with the mattress extending over the keeper board. The mattress includes a fabric enclosure having a plurality of separate compartments within the enclosure, and comminuted rubber from used vehicle tires is disposed within each compartment. A top fabric blanket is disposed over the mattress with an end of the blanket attached to the keeper board, and an opposed end of the blanket attached to the brisket board.
    Type: Grant
    Filed: July 18, 1995
    Date of Patent: August 5, 1997
    Assignee: Promat Ltd.
    Inventor: Stuart Douglas Young