Brilliant displays.

November 20 07 T he next time you buy a cell phone, take a close look at the display panel. If things go the way Qualcomm hopes, that colorful little rectangle could give a whole new meaning to the expression “butterfly effect.” True, the interferometric modulator (IMOD) displays recently introduced by the San Diego– based firm have nothing to do with the unexpectedly strong effect a wing beat can theoretically have on the weather. But the devices do use an array of artificial microstructures to produce the same kind of iridescent colors as are seen on the wings of tropical butterflies. And Qualcomm is betting that its approach will give IMODs several advantages over today’s dominant liquid-crystal-display (LCD) technology. Most important is that an IMOD display is much easier on a handset’s battery—a characteristic that will matter more and more as people increasingly use cell phones for Web browsing, text messaging, and playing games, videos and music. Such intensified use poses a severe power-management challenge for LCDs, most of which cannot be read at all unless they have a backlight shining up through them. But an IMOD display simply reflects ambient light the way paper (or a butterfly wing) does. “So an IMOD consumes as little as 6 percent of the handset’s battery power, versus nearly 50 percent for an LCD,” says James Cathey, Qualcomm’s vice president of business development. And that means that an IMODequipped handset should run a lot longer on a single charge—even allowing for the supplementary illumination it would need for low-light situations. “In a typical usage scenario, we estimate that an IMOD-equipped phone would give you 140-plus minutes of video time, versus 50plus minutes with an LCD display,” he notes. Being reflective, IMOD displays are also far easier to read in bright daylight: rather than turning black, as most LCD displays effectively do, they actually get clearer and more vivid. “If you’re using your phone for video, text, pictures, you want the same viewing quality in many environments,” Cathey says. IMOD displays can also switch their basic unit cells on and off within about 10 microseconds, roughly 1,000 times faster than LCD displays can, a feature that makes them considerably better suited to video. And IMOD displays are at least as rugged as LCDs. Qualcomm has tested the IMOD unit cells through at least 12 billion on-off cycles, the equivalent of more than seven years of continuous operation, without a failure. Of course, there are many other alternatives to LCDs, ranging from OLEDs (organic light-emitting-diode) displays to electrophoretic “e-paper” A new technology that mimics the way nature gives bright color to butterfly wings can make cell phone displays clearly legible, even in the sun’s glare