Abstract: A ceiling mounted passive infrared detector has an enclosure arranged for mounting to ceiling, a downwardly pointing infrared detecting element within the enclosure, a first multifaceted pyramidal mirror having an apex pointing upwardly toward the detecting element and a plurality of focusing lenses, one for each facet of the mirror and mounted between the base of the pyramidal mirror and the periphery of the enclosure to focus infrared radiation onto the detecting element directly and via reflection in the pyramidal mirror. A further embodiment includes the enclosure wherein the lenses are disposed on the plane immediately above the apex of the mirror so that radiation will be reflected off the mirror and refracted by the lenses onto the detecting element.

Abstract: A ceiling mounted passive infrared intrusion detector includes a window which has an exterior surface with ridges formed of intersecting planes, which are arranged to provide internal reflection of radiation received from selected angles with respect to the optical axis of the device and to deflect such radiation into a direction parallel to the optical axis. Focusing means arranged as part of the detector focuses the parallel infrared radiation onto a detecting element within the device.

Abstract: A lighting control device utilizes an infrared occupancy detector in order to control the lights in a room or area. The occupancy detector monitors changes in infrared energy, which indicate movement within the area, by receiving infrared energy in a plurality of fields of view spread out over an arc of approximately 180.degree.. As a result the device may be installed on a wall of a room or area and still cover the entire area. The wide spread of the fields of view is accomplished with off-axis Fresnel lens segments arranged in series and by partially reflecting the energy received by some of the lens segments into the infrared detector.