Design of a highly integrated ultrasonic piezoelectric controller

While touch screens have become the de facto user interface for cell phones, they do not provide any mechanical feedback to the user, unlike standard keyboards and computer mouse where we can feel the buttons springing back against our fingers. This, however, could be replicated through haptic technology, which can mimic various sensations through smooth surfaces (touch screen or phone case). For example, a haptic device can simulate the sensation of pressing a button.