Abstract: A device for receiving light beams, especially a PIR movement detector, includes a housing having at least one window in which lens segments, preferably Fresnel lenses, are disposed in such a way that horizontally incident light beams are focused as direct horizontal beams onto two light sensors. The two light sensors are mutually disposed in such a way that a usable sensor detection angle of the two light sensors is defined. In order to achieve an enlargement of the detection angle, at least one horizontal reflector is disposed in the vicinity of at least one of the light sensors, in such a way that the horizontal reflector detects further light beams from a horizontal angular region not covered by the light sensors with the usable detection angle, and these beams reach at least one of the light sensors as reflected horizontal beams.

Abstract: A passive infrared motion indicator installed at a distance above the ground includes a housing having at least one housing recess formed therein. A Fresnel lens system is disposed in the at least one housing recess. At least one infrared sensor disposed inside the housing has Fresnel lenses onto which frontally arriving first infrared rays with a horizontal main ray are directed from a first detection area and deflected onto the infrared sensor and Fresnel lenses onto which laterally arriving second infrared rays with a horizontal main ray are directed from a second detection area and reflected onto the infrared sensor. At least one deviation mirror surface is tilted above the horizontal main rays of the first and second infrared rays for intermediately deflecting third infrared rays arriving from a third detection area disposed below the passive infrared motion indicator between the ground and the first and second detection areas, onto the infrared sensor.