Door or window break-in detector - uses fibre optic encased in panel and having ends terminated at light emitter-receiver

摘要

The break-in detector has a fixed light emitter (12). An optical system (8) receives the light beam from the emitter and returns the beam into a receiver (14). The optical system (8) is fixed to a movable panel (2) so that it is made ineffective if the panel is broken or displaced. With the panel closed the receiver (14) furnishes an output signal representative of the intensity of the beam it receives. The break-in detector (16) is controlled by the output signal of the receiver. The optical system (8) is a fibre optic which is glued to the panel. The receiver and emitter are integrated into a single unit (10).