USA: Touch screens have the Midas touch for growth, spurring a flood of competition, technologies and OEM interest. iSuppli Corp. has predicted global shipment revenue for the leading touch-screen technologies will rise to $4.4 billion by 2012, up from $2.4 billion in 2006.

Projected gains
"Catalyzed by Apple Inc.'s iPhone, sales of touch screens using projected-capacitive technology are growing dramatically," said Jennifer Colegrove, senior analyst for emerging displays at iSuppli.

"Projected capacitive touch screen technology is more durable and has better transmittance than the more commonly used resistive technology. More touch-screen manufacturers are developing and commercializing this type of screen. Furthermore, the average pricing gap between the capacitive and resistive display types is dwindling, making the technology more attractive."

Can't resist
Resistive is the most commonly used touch screen technology in the marketplace. Although it is not very durable and has poor transmissivity, resistive's low price and responsiveness to both finger and stylus touch has made it the No. 1 touch screen technology in terms of unit shipments during the last few years.

However, the resistive market now is suffering 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. In fact, Fujitsu Ltd. already has started using conductive polymer for some of its resistive-type touch screens.

iPhone impact
Since the iPhone proved that multi-touch technology can be portable and affordable, multi-touch has become the hot topic in the industry.

Many providers of alternative touch-screen technologies have announced multi-touch capabilities, such as the optical imaging camera-based touch screens offered by touch screen designer and developer NextWindow Ltd. Other examples include IR Touch Systems Technology Co. Ltd's infrared touch screen and Stantum Inc. — formerly named JazzMutant — which has offered a multi-touch music controller since 2004.

Feel the touch
Tactile feedback technology is finding usage in increasing numbers of touch-screen devices. The technology delivers a physical sensation similar to that of pressing a physical button. Tactile feedback is the differentiating factor for some new mobile phones, such as the Motorola Rokr E8.

Handset tests
Although resistive is the dominant touch-screen technology for mobile phones, projected capacitive and infrared began to penetrate the wireless handset segment in 2007. Technological variations being commercialized on mobile phones in 2008 and 2009 include sensor-in-pixel or in-cell touch, bending wave from Elo/Tyco Electronics, and polymer waveguide from RPO Inc.

Large-sized touch screens
Retail, kiosk, public signage, financial, e-book and medical applications are adopting more touch-screen monitors to accommodate consumer preferences for intuitive and easy user interfaces. Consumers want this kind of ease of use when they check out at a grocery store, or check in at an airport. Such touch-screen monitors reduce labor costs for stores or for other institutions.

Despite the total of eight distinct, commercialized touch-screen technologies, i.e. resistive, surface capacitive, projected capacitive, surface acoustic wave, infrared, bending wave, active digitizer, optical imaging, even more novel touch-screen approaches have been invented. These include new touch technologies from N-trig, Sony, Sharp, TMD and Samsung. Several companies recently have announced plans to commence touch-screen manufacturing. Furthermore, several mergers and acquisitions have occurred, launching new participants into the market.

For the touch-screen market, with more than 100 suppliers, in excess of 300 OEM/integrators and a wealth of technological alternatives, fascinating times are ahead.