Touchscreen panel haptics
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Abstract
A touchscreen system for generating localised haptic excitations includes a touchscreen panel for measuring force and/or capacitance. The touchscreen system includes one or more first piezoelectric transducers arranged to generate excitations in the touchscreen panel along a first line. The touchscreen system includes one or more second piezoelectric transducers arranged to generate excitations in the touchscreen panel along a second line which is inclined to the first line at an angle. The touchscreen system includes a pressure and/or capacitance sensing module connected to the touchscreen panel and configured to measure a force and/or capacitance from the touchscreen panel. The touchscreen system includes a haptic driving module connected to the first and second piezoelectric transducers and configured to generate user perceptible haptic excitation by driving the first piezoelectric transducers at a first frequency, and driving the second piezoelectric transducers at a second frequency, wherein the difference of the first and second frequencies is a beating frequency, and the beating frequency is a frequency perceptible by human skin, or by driving the first and second piezoelectric transducers at a carrier frequency which is modulated at a modulation frequency which is a frequency perceptible by human skin. The angle is selected to cause Moiré fringes between excitations generated along the first line and the second line.