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.