Dew/Frost Point Recognition With Impedance Matrix of Fingerprint Sensor

In dew point hygrometers, the condensed-water-layer thickness as well as the morphology can modify the detector signal value that gives unreliable detections. The classic impedance dew/frost point detector measures the mean impedance of the whole active detector area; therefore, in the case of the simultaneous presence of both forms of water (liquid supercooled water and ice) or in the case of various morphologies of water droplets or crystals, it is difficult to distinguish those situations from regular operations. The new idea of dew/frost point detector construction based on impedance matrix measurement was described. To test the idea of an impedance matrix dew/frost point detector, the finite-element simulations were done. Then, a commercially available fingerprint sensor was successfully applied.