The trouble with touch screens - [update]

Chances are that if you purchased a new handheld gadget this holiday season, it had some kind of touch screen. That¿s good news for touch-screen makers, but they face a problem that is literally invisible. Indium-tin oxide (ITO), the transparent conductor used in touch displays, is in short supply. In fact, experts predict that we could run out of indium, a silvery metal produced as a by¿product of zinc mining, in the next 10 years. The price of the metal has shot up from around US $100 per kilogram to nearly $1000 in the past six years. Fortunately, many companies and research groups are coming up with alternatives to conventional ITO technology.