Patent ID: 7236616

Claim:
A piezoelectric film fingerprint scanner comprising: an oscillator that generates an oscillation signal; a gate counter coupled to said oscillator that counts cycles of said oscillation signal generated by said oscillator; a controller coupled to said gate counter and each of a row multiplexer and a column multiplexer, said controller controls said row and column multiplexers responsive to said gate counter; a pulser coupled between said gate counter and said row multiplexer, said pulser sends an input pulse of one cycle of said oscillation signal to said row multiplexer; a piezo film sensor array including a first conductor grid coupled to said row multiplexer and a second conductor grid coupled to said column multiplexer, said first and second conductor grids disposed on first and second respective sides of said piezo film; and a voltage detector coupled to said gate counter and to said column multiplexer, said detector detecting a voltage corresponding to a pixel or group of pixels of said piezo film sensor array selected by said row and column multiplexers; wherein the voltage detector is configured to detect the voltage a predetermined number of cycles after the pulser sends the input pulse.