What uncooled technology is used in the PV320 and how does it compare with other uncooled imaging technologies?
Two basic uncooled detector types have emerged today, ferroelectric detectors and microbolometers. Ferroelectrics have been developed by Raytheon and GEC Marconi; microbolometer technology has been developed by Honeywell and others. Ferroelectric detector technology (as used in the PV320) takes advantage of a ferroelectric phase transition in certain dielectric materials. At and near this phase transition, the electric polarization of the dielectric is a strong function of temperature; small fluctuations of temperature in the material cause large changes in polarization. Then, if the sensor is maintained at a temperature near the ferroelectric phase transition and if the optical signal is modulated (with a synchronous chopper), then, an infrared image can be readout that reflects the scene temperatures. Microbolometer arrays, on the other hand, consist of detectors made from materials whose electrical resistivity changes with temperature. Each detector is part of a readout circuit that
