METHOD AND APPARATUS FOR DETECTING TWO SIMULTANEOUS TOUCHES AND GESTURES ON A RESISTIVE TOUCHSCREEN

摘要

A resistive touchscreen system (100) has coversheet (102) and substrate (104) with first and second conductive coatings (106,108). The coversheet and substrate are positioned proximate each other such that the first conductive coating faces the second conductive coating. The coversheet and the substrate are electrically disconnected with respect to each other in the absence of a touch. A first set of electrodes (110,112) is formed on the coversheet for establishing voltage gradients in first direction. A second set of electrodes (120, 122) is formed on the substrate for establishing voltage gradients in second direction wherein the first and second directions are different. A controller (138) biases the first and second sets of electrodes in first and second cycles and senses a bias load resistance associated with at least one of the sets of electrodes. The bias load resistance has a reference value associated with no touch and a decrease in the bias load resistance relative to the reference value indicates two simultaneous touches.