US 4707604

CEILING MOUNTABLE PASSIVE INFRARED INTRUSION DETECTION SYSTEM

Assignee

AMERICAN DISTRICT TELEGRAPH COMPANY, ONE WORLD TRADE CENTER, SUITE 9200, NEW YORK, NEW YORK, 10048, A CORP OF NEW JERSEY

Filed

Oct 23, 1985

Granted

Nov 17, 1987

Location

LYNNFIELD MA US

Abstract

The disclosed ceiling mountable passive infrared intrusion detection system includes a field forming mirror assembly and a focusing mirror assembly cooperative to provide a field of view having plural first vertical curtains, a generally disc-shaped horizontal second curtain, and a generally conical downwardly directed third curtain. In one embodiment, first and second conical field forming mirrors are cooperative with different and spaced-apart spherical focusing mirrors to provide the horizontal curtain and the downwardly directed conical curtain. An unbalanced detector is disclosed that cooperates with the energy pattern received from the conical field forming mirrors to signal intruder presence. In another embodiment, first and second pluralities of planar field forming mirrors are cooperative with the different and spaced-apart spherical focusing mirrors to respectively provide a first plurality of substantially horizontal finger beams and a second plurality of plural downwardly directed finger beams. In this embodiment, a balanced detector is disclosed that cooperates with the energy pattern received from the first and second pluralities of finger beams to signal intruder presence.

Source: Google Patents