Patent ID: 6294784
Filing Date: 2001-09-25
Classification: G01J

Abstract:
A pyroelectric sensor system comprising:an alternating voltage source generating an alternating voltage at a predetermined frequency;a pyroelectric sensor element responsive to the alternating voltage, said pyroelectric sensor element generating a hysteresis loop charge output in response to the alternating voltage, said alternating voltage driving the sensor element over at least a portion of the hysteresis loop output of the element, said pyroelectric sensor element having a composition so that the alternating voltage causes a polarization reversal of dipoles in the element in response to positive and negative changes of the alternating voltage; anda charge integration system responsive to the charge output from the pyroelectric sensor element, said integration system determining the area within the hysteresis loop defined by the hysteresis loop output and generating a signal indicative of the charge output from the sensor element.