Ceiling mounted passive infrared intrusion detector with dome shaped lens.

摘要

A passive infrared intrusion detector is arranged for mounting to the ceiling of a room to be protected. Infrared radiation from points within the room is focused onto an infrared sensing element by a multi-segment dome-shaped lens. The multi-segment lens in a preferred embodiment has central, downwardly facing beams of infrared sensitivity and other beams of infrared sensitivity at multiple azimuth angles at selected elevation angles.