Wigdor at MERL, and Patrick Baudisch at Microsoft Research has created a new gadget with a transparent touchscreen! The major difference between this device and other touchscreens is that the sensing panel -- on this machine -- is on its back, instead on the screen. The duo says "using your fingers behind the device allows a firmer grip and more accurate performance without obscuring your view of the screen."
(Video after the jump)

When using the rear touch interface, the user's fingers appear as shadows on the screen, giving the illusion they are holding a transparent device. LucidTouch highlights the active point of each finger with a small green dot, removing the fat finger problem. "We're trying to address the problem of occlusion by giving the user an idea of their input, while still being able to see through the hands to the screen," Wigdor says.

The device will not hit the market anytime soon as there are some problems which needs to be solved such as how to slim down the LucidTouch design.

Source