Abstract: Systems and methods are disclosed for reducing susceptibility of touch screens to RF interference, thereby reducing susceptibility to touch position errors due to RF interference. In touch screen systems having touch sensors that lack a rear shield, the rear shield drive of the controller electronics can be capacitively connected individually to the touch signal drives, thereby placing a capacitive load on the touch signal drives that simulates the capacitive load that would otherwise be provided by a rear shield. This capacitive load compensates for the RF interference, which would otherwise tend to erroneously offset touch position determinations toward the center of the touch screen.

Abstract: Bending wave vibrations propagating in a substrate of a touch input device are sensed. Provision is made for discriminating between sensed vibrations propagating in the substrate indicative of an intended touch and sensed vibrations propagating in the substrate indicative of an unintended touch. In response to the sensed vibrations propagating in the substrate indicative of the intended touch, a wake-up signal is generated. The wake-up signal is communicated to a control system of the touch input device for transitioning the control system from a sleep state to an operational state.