pad 13 by external voltage drivers and when the contact surface 14 is uniform the charges induced on the pick up pad 13 are zero or close to zero as shown in fig1 a note that although only one pixel is illustrated the actual device comprises a two dimensional array of pixels however if the surface in contact 15 is non symmetric as shown in fig1 b then the fields become distorted and the induced charges on the pick up pad 13 do not cancel and the pick up pad 13 registers a signal which is interpreted as the presence of a finger surface ridge pixel 10 further comprises shield 16 signal lines 17 substrate 19 insulation layers 21 and 23 and electrode pads 27 and 29 a positive voltage is applied to pad 27 a negative voltage is applied to pad 29 formed on conductive layer 2 shield layer 16 serves to block fields emanating from electrodes 27 and 29 such that readout lines 17 are not effected by the staying fields substrate 19 can be formed of an insulating material or a semiconductive substrate with an insulation coating the entire structure of the sensor is essentially alternating layers of conductors and insulators with conductive layers patterned in certain ways and the insulator layers patterned with holes therefore the fabrication of the sensor requires simple inexpensive machines with no active elements in the sensor array itself this makes the sensor immune to the high voltage static damage unlike the silicon chip sensors of the prior art in addition the sensor can be made on.