Nanotouch back-of-device interaction for very small screens

Patrick Baudisch and Gerry Chu of Microsoft Research have done some really interesting work on placing touch interfaces on the back side of very small devices. This is the latest refinement of an idea they presented last year called "Lucid Touch". Putting touch on the back of the device addresses the occlusion and "fat finger" problems of touchscreens and enables touch interaction on very small devices.

They have a project page which includes videos and a pdf of a paper that they will present at CHI 2009. In the paper they describe experiments to compare pointing performance of back-of-device interaction compared with the "shift" technique.

Here is some video of the device (via a New Scientist article about the project):