Patents Assigned to Racal-Guardall (Scotland) Ltd.
  • Passive infra-red sensor
    Patent number: 4734585
    Abstract: A passive infra-red sensor includes a window in a housing which also houses an infra-red detector. The window defines a plurality of infra-red transmitting strips which are separated by Fresnel lens segments or infra-red opaque strips. The infra-red transmitting strips provide short range sensitivity. The Fresnel lens segments where provided give longer range sensitivity.
    Type: Grant
    Filed: July 16, 1986
    Date of Patent: March 29, 1988
    Assignee: Racal-Guardall (Scotland) Ltd.
    Inventor: Ian A. Owers