This lens is widely used in Senba SMD series pyroelectric infrared
sensor, human body switch, alarm infrared thermometer and infrared
imaging. It can provide users with different induction angles, one is
the focusing effect, the other is to divide the detection area into
bright and dark areas, so that the moving objects entering the detection
area can generate changing thermoluminescent infrared signals on the
PIR(passive infrared detector) in the form of temperature changes.