Sawtooth planar waves for haptic feedback

Current touchscreen technology does not provide adequate haptic feedback to the user. Mostly haptic feedback solutions for touchscreens involve either a) deforming the surface layers screen itself or b) placing actuators under the screen to vibrate it. This means that we have only limited control over where on the screen the feedback feels like it is coming from, and that we are limited to feedback that feels like movement up and down, orthogonal to the screen. In this work I demonstrate a novel technique for haptic feedback: sawtooth planar waves. In a series of paper Canny & Reznick showed that sawtooth planar waves could be used for object manipulation. Here that technique is applied to haptic feedback. By varying the input waves, from 1 one to 4 actuators, it is possible to provide feelings of motion in any planar direction to a finger at one point on the screen while providing a different sensation, or none at all, to fingers placed at several other points on the screen.