The iPhone has influenced handset design in many ways but none so much as the use of touchscreens which are now in huge demand. A report from iSuppli says touchscreens will be a $4.4bn market by 2012, up from $2.4bn in 2006.

“Sales of touch screens using projected-capacitive technology are growing dramatically,” said iSuppli analyst Jennifer Colegrove, “projected capacitive touch screen technology is more durable and has better transmittance than the more commonly used resistive technology.”

Another factor helping the growth of capacitive touch is cost. The cost differential between capacitive and resisitive is dwindling, said iSuppli.

 Moreover, the resistive manufacturers are  suffering, said iSuppli, a shortage of Indium Tin Oxide (ITO) film used to make such screens due to production expansions among several major manufacturers and limited numbers of ITO film suppliers.

With several large manufacturers expanding capacity, other types of transparent conductive materials such as conductive polymer, carbon nanotube and Antimony Tin Oxide (ATO) have an entry opportunity now.

Southampton company Quantum Research, which was sold earlier this year to Atmel for $88m, invented a method of capacitive sensing it calls charge transfer capacitive sensing which Motorola uses it in its mobile phone keypads, and  Apple uses in the  wheel control of some of its iPods.