Sensor device having thermally-insulated detector

A sensor device configured to detect an occupancy condition in a space, the sensor device comprising:

• an enclosure having an aperture in which a lens is received, the lens centered about a first axis that extends in a longitudinal direction;
• a printed circuit board housed within the enclosure, the printed circuit board having a front surface and a rear surface, the printed circuit board including a ground plane that covers at least a portion of the front surface;
• a passive infrared sensing circuit including a detector having an opening for receiving infrared energy, the detector mounted to the front surface of the printed circuit board, such that the opening of the detector is substantially centered about the first axis of the lens, the detector configured to receive infrared energy through the lens and generate an output signal in response to the received infrared energy, the passive infrared sensing circuit configured to generate an occupant detection signal based on the output signal generated by the detector;
• a light-emitting diode at a location such that when illuminated, light from the light-emitting diode illuminates the lens, wherein the location of the light-emitting diode is such that the light-emitting diode is mounted to the front surface of the printed circuit board and spaced apart from the detector along a second axis that extends in a radial direction and passes through the first axis of the lens, wherein at least a portion of the ground plane is located along the second axis between the detector and the light-emitting diode;
• and
• a control circuit configured to receive the occupant detection signal and to determine the occupancy condition in the space in response to the occupant detection signal, the control circuit further configured to control the light-emitting diode to illuminate the lens;
• wherein the ground plane comprises a gap located along the second axis in the portion of the ground plane located between the detector and the light-emitting diode, the gap in the ground plane configured to reduce a thermal transfer of heat generated by the light-emitting diode to the detector.