Patent attributes
An apparatus (22) for processing signals from a touch panel (10) is described. The touch panel (10) includes a layer of piezoelectric material (16) disposed between a plurality of sensing electrodes (14, 20) and at least one common electrode (15). The apparatus (22) includes a first circuit (23) for connection to the plurality of sensing electrodes (14, 20). The first circuit (23) is configured to generate one or more first pressure signals (29). Each first pressure signal (29) corresponds to one or more sensing electrodes (14, 20) and is indicative of a pressure acting on the touch panel (10) proximate to the corresponding one or more sensing electrodes (14, 20). The apparatus also includes a second circuit (24) for connection to the at least one common electrode (15). The second circuit (24) is configured to generate a second pressure signal (30) indicative of a total pressure applied to the touch panel (10). The apparatus also includes a controller (25) configured to determine an estimate of the total pressure based on a weighted difference of the second pressure signal (30) and a sum over the one or more first pressure signals (29).
