Patent attributes
A low cost, two-dimensional, fingerprint sensor includes a pixel array, each pixel including a switch and a pixel electrode for forming a capacitance with a fingertip. One or more active transmission electrodes are spaced from a selected row of the pixel array, and transmit a carrier signal into the finger without direct coupling into the selected pixels. Signals sensed by the pixel array are coupled to an independent integrated circuit, and connections between the IC and the pixel array are reduced by demultiplexing row select lines, and by multiplexing sensed column data. Differential sensing may be used to improve common mode noise rejection. The fingerprint sensor may be conveniently incorporated within a conventional touchpad LCD panel, and can mimic the performance of lower density touchpad pixels.
