UV downlight with intelligent irradiance control

An apparatus comprising:

• a first light source that emits disinfecting light;
• a second light source that emits white light;
• a beam angle adjustor that controls a beam angle of the first light source and indicates the beam angle;
• a distance sensor that indicates a distance from the first light source to a target surface that is irradiated by the first light source;
• a motion sensor that indicates sensed motion in a volume of space that is greater than a volume of space in which the first light source emits the disinfecting light;
• and
• a processor configured to:
• calculate and set a radiance of the first light source based on the beam angle indicated by the beam angle adjustor and the distance from the first light source to the target surface indicated by the distance sensor in order to achieve a predetermined irradiance of the target surface;
• partially reduce the radiance of the first light source when the motion sensor detects motion and the distance sensor does not detect a change in the distance;
• and
• zero the radiance of the first light source when the motion sensor detects motion and the distance sensor detects a change in the distance.