Sensor employing overlapping grid lines and conductive probes for extending a sensing surface from the grid lines

A fingerprint sensor, comprising:

• a first conductive layer formed as a plurality of parallel drive lines;
• a second conductive layer formed as a plurality of parallel pickup lines, wherein the plurality of parallel drive lines are oriented transversely to the plurality of parallel pickup lines;
• a dielectric layer separating the first conductive layer and the second conductive layer, wherein each crossover location at which one of the pickup lines overlaps one of the drive lines defines an impedance sensitive electrode pair;
• a detecting circuit configured to detect a signal at each impedance sensitive electrode pair;
• an overlay layer formed of an insulating material and located over the first conductive layer and the second conductive layer;
• and
• a plurality of conductive probes embedded within the overlay layer, wherein each of the plurality of conductive probes has a first end and a second end, wherein the first end of each conductive probe is in proximity to an associated one of the crossover locations, and wherein the second end of each of the conductive probes is in proximity to an outer surface of the overlay layer to extend a sensing surface of the fingerprint sensor from a top surfaces of the pickup lines to the outer surface of the overlay layer.