Forget those fancy capacitive or resistive touchscreens. Nokia's new haptic display is cool as ice, literally. The Finnish phone company created a concept multi-touch surface entirely out of frozen water.
First off, they took a ton of ice, cut them up into blocks, then gave it a smooth polish with a heat gun. An infrared light is then projected onto the icy display, bouncing off of a user's hand. A computer tracks movement on the ice screen, then provides corresponding visual output through a second projector.
It's not exactly portable, and would most likely be useless anywhere south of Finland. The Nokia team responsible claim that it's all for fun, but did think of possible applications, such as interactive public displays in places where the sun wouldn't be a concern. They should also consider marketing it to various ice-themed villains, like Mr. Freeze.
[source: New Scientist]