Patents Assigned to Racal-Guardal (Scotland) Limited
  • Security sensors
    Patent number: 4912331
    Abstract: A system for locating zones defined by Fresnel lens segments or mirror facets of an optical arrangement in a passive infra-red security sensor uses a prism sheet which deflects light emitted by an LED mounted to the circuit board adjacent the infra-red sensitive detector so that it follows the path of infra-red radiation that would be focused onto the element of the detector without the prism sheet present.
    Type: Grant
    Filed: March 6, 1989
    Date of Patent: March 27, 1990
    Assignee: Racal-Guardal (Scotland) Limited
    Inventor: Ian A. Owers