Here is something really innovative,a touch screen called Nanotouch given by students and researchers of University of Toronto. It is a 6cm screen and a touch pad of same size at the back.It can detect a touch or press of a finger ,allowing to move a tiny cursor around and click and drag with it.
WHen you touch the interface on the back,an image of finger appears behind the icons on the screen and moves aroundin sync with your finger,almost as if the device were transparent.A small active spot marked on the finger's end is used to interact with button onscreen.User tests showed that target just 1.8mm across were easy to hit using NanoTouch. Targets on coventional touch-screen devices such as the iPhone are atleast twice that size.