Getting the skinny on mobile displays

At the Society for Information Display's Mobile Displays Conference 2006 here, they, along with manufacturers and analysts, are tackling such hot topics as how to build super-slim mobile devices with screens readable in sunlight while lowering power consumption, and of course, designing sleek devices that will garner "it-gadget" status.

Mobile displays have come a long way in a short time--the conference, in fact, is SID's first ever to focus solely on the topic. Just five years ago, the conversation about screens on portable gadgets such as phones, game devices and PDAs revolved around monochrome. Today, people are talking about how many colors they can squeeze out. Soon, the brightness and resolution of many displays is expected to rival some laptop computer and TV displays.

The industry is innovating quickly and the numbers show it. The small- and medium- size mobile-display market (less than 10 inches) will do $23 billion dollars in sales by the end of 2006, according to Paul Semenza, vice president of iSuppli. That's about 3.5 billion displays sold, and they go into everything from PlayStation Portables to iPods, digital still and video cameras, navigation devices, watches and portable TV and video devices.

But the biggest driver of mobile displays is mobile phones, which are ubiquitous, according to Jim Zhuang, manager of Motorola's display group, because they are "essential to everyday life." The mobile-phone industry is "the most promising industry of the future," he told conference attendees. That may sound like a brash assessment, but between 900 million and 1 billion mobile handsets will ship this year, and the market has grown steadily at a rate of 25 percent since 2003, Zhuang said.

More small mobile displays will go into mobile phones than into any other portable device, according to Vinita Jakhanwal, principal analyst for mobile displays at iSuppli. The most important factor in making and selling a successful phone is its thinness, according to Zhuang, as evidenced by the recent introduction of ultra-slender handsets like the Samsung Trace, LG Chocolate, Motorola Krzr and others. The slim-phone craze has been driven by Motorola's highly successful Razr, which sports a 4-millimeter thick display.

Does skinny equal weak?
Just last week, LG.Philips LCD debuted the slimmest display yet, a thin-film transistor liquid crystal display (TFT-LCD) measuring 1.3 millimeters thick. The slimming-down trend, according to Zhuang, is sure to continue.

But not all display makers are sure thin is best. "How are you affecting the ruggedness of a display?" Palm senior display engineer Kevin Lee asked the audience rhetorically. "Is it worth it making the display 40 percent weaker" just to be thinner? Translation: Glass stretched really thin can break if dropped.

Samsung LCD says it's already on top of that potential problem. "Thin is definitely in," said Joe Virginia, vice president of Samsung LCD, but "that thin glass needs much higher strength." He said Samsung's process of grinding display glass to less than half a millimeter thick retains its durability.

Besides determining the size of a mobile device, a display is also its biggest battery hog. "More features in a device means people use them for more hours per day, and power consumption is a concern," said Miles Kirby, senior director for product management at Qualcomm. Power affects everything--standby, talk and usage time--and being forced to put a bigger battery in any device will affect its overall design, Palm's Lee pointed out.

Intel is attempting to tackle the issue with its new Display Power Saving Technology (DPST) for portable gadgets, which will reduce the backlight power while simultaneously offering better image quality, according to Achin Bhowmik, Intel's manager of mobile platforms. The technology, designed to transparently adjust graphics and video images before they are transmitted to the display panel, will prolong battery life by 30 minutes, he told the crowd. Rather than handsets, like Motorola and Nokia, the chipmaker is heavily pushing the technology for ultramobile PCs.

No matter the type of device, being able to actually see its screen outdoors is critical. Scrolling through e-mail on a BlackBerry at a baseball game, or selecting an iPod playlist while standing at a bus stop, is essential, display manufacturers agree, and most current devices sporting LCD displays are practically impossible to see outdoors. As Barry Young of DisplaySearch said simply, displays "must be outdoor-readable."

Qualcomm, for one, is choosing to use sunlight instead of fight it. Its interferometric modulator (iMoD) displays don't use a backlight, reflecting ambient light instead. Qualcomm says iMoD displays will start showing up in mobile handsets, wrist-worn devices and portable music players in the future.

Samsung SDI and LG.Philips both talked up active matrix organic light-emitting diode (AM OLED) displays for their visibility in sunlight. AM OLED displays use an organic material compound underneath the glass that emits red, green and blue light. The benefit is its near 100 percent ability to display the full range of colors. More colors means better readability, even outside, according to Chang Hoon Lee, general manager of AM OLED for Samsung SDI.

But despite concerns over functionality with mobile devices, gaining style points with consumers is still a major goal, and clearly displays are a big part of that. Gadget purchases, especially of phones, now are symbolic of a lifestyle choice, and that's something even display designers need to address, according to Motorola's Zhuang. "It's about making a statement," he said. "This drive to make it more stylish will put even more pressure on mobile displays."