System and method of using an electric field device

A biometric scanner, comprising:na TFT array, including:nan electric field generator that is prevented from providing an electric field to a biometric object or the TFT array not having an electric field generator, and having an electric field sensor array comprised of a plurality of electric field sensors, each of the electric field sensors including:na first capacitor;a diode;a first transistor; anda second transistor;wherein the first capacitor is configured to capacitively couple to the biometric object;wherein the first capacitor is in electrical series with the diode, the first transistor, and the second transistor;wherein a first bias is in electrical series with the diode and the first transistor; andwherein the second transistor is coupled to an output; anda computer coupled to receive capacitance readings from each output of the plurality of electric field sensors on the TFT array.

A method of scanning a biometric object, comprising:n(i) provide a TFT array (a) having no electric field generator, or an electric field generator that is prevented from providing an electric field to a biometric object or the TFT array, and (b) having an electric field sensor array comprised of a plurality of electric field sensors, each of the electric field sensors including:na first capacitor;a diode;a first transistor; anda second transistor;wherein the first capacitor is configured to capacitively couple to the biometric object;wherein the first capacitor is in electrical series with the diode, the first transistor, and the second transistor;wherein a first bias is in electrical series with the diode and the first transistor andwherein the second transistor is coupled to an output; and(ii) capacitively couple a biometric object to the TFT array;(iii) receive capacitance readings from each output of the plurality of electric field sensors on the TFT array;(iv) determine values representative of the biometric object based upon the received capacitance readings.