Patent ID: 7875853

Claim:
A passive infrared sensor, comprising: a sensor housing including a first circuit board; a filter housing including a second circuit board, the filter housing positioned within the sensor housing; a filter positioned in the filter housing and the filter being transparent to a first specified wavelength band of radiation and the filter blocking a second specified wavelength band of radiation outside the first specified wavelength band of radiation; a liquid crystal display (LCD) attached to the sensor housing; at least one pyroelectric element electrically connected to the second circuit board; a microprocessor electrically connected to the first circuit board; at least one lens attached to the sensor housing and overlapping the LCD, the at least one lens having at least first and second lens regions corresponding to at least first and second LCD regions, the at least first and second LCD regions being individually controlled by the microprocessor to distinguish between at least first and second fields of view by selectively preventing radiation energy at a first angle from passing to the at least one pyroelectric element while selectively allowing radiation energy at a second angle to pass to the pyroelectric element; and the microprocessor receiving an electrical signal generated from the at least one pyroelectric element and initiating an alarm signal when radiation within the first specified wavelength band reaches the at least one pyroelectric sensor.