Today’s flat-panel displays provide bright, crisp, and vivid images—and they use plenty of power while doing it. It’s a tradeoff that hardly mattered when we rarely watched movies, played games, or surfed the Web on anything other than furniture-size monitors. But that power consumption is a serious engineering constraint today, when more and more of us are getting our visual data on the go, from cellphones, video iPods, and game players like Sony’s PSP. And as serious as the constraint is now, it will soon become downright intolerable as engineers strive to wring far more vivid visual information out of the next generation of portables than can be displayed by anything now on the market.

Fortunately, remarkable power savings—as much as 50 percent—can be achieved by simply redesigning the display to provide no more information than the eye can absorb and the brain can digest. This strategy is called biomimetic, because it deliberately mimics a living system.

Biomimicry has long been used in audio. For many years microphones, amplifiers, and speakers have been designed in sizes and frequency ranges that match the human auditory system. Similarly, the telephone system crams calls through limited carrying capacity by editing the frequencies down to a limited bandwidth. Such compression techniques have also been applied to audio and video software, as seen in the Moving Picture Experts Group (MPEG) and other algorithms. Now it is time to apply biomimicry to displays.

It all begins with the retina, the part of the eye that converts photons into electrochemical signals that are interpreted by the brain as images. The retina’s most discerning photosensitive elements, or photoreceptors, are the cones. Except in a color-blind person, the human eye has three kinds of cones, each having a different type of protein, called a photopigment.

One kind of photopigment is specialized to sense photons in the reddish-yellow band of wavelengths, the second in the greenish-yellow band, and the third in the blue one. Because the typical eye has about 30 red- and green-sensitive cones for every blue one, almost all the work of resolving an image—its luminance, edges, and other structural detail—is done with output from the red and green cones, which also detect color, of course. The blue cones detect only color [see sidebar, “The Human Visual System at a Glance”].

Yet despite the great preponderance of red and green cones in our eyes, most flat-panel displays produced today, like just about every color TV tube produced in the past half century, have a 1:1:1 ratio of red, green, and blue color elements. These elements, called subpixels, are arranged in either a stripe or a delta pattern [see illustration, “Tradeoffs”]. Because the blue subpixels do almost nothing to help the eye resolve images, most of it goes to waste.

Over the years, researchers have come up with ways to minimize the waste. In the 1970s, Bryce Bayer, of Eastman Kodak Co., came up with the Bayer pattern, with a 1:2:1 ratio of red, green, and blue subpixels, with the green subpixels linked diagonally, as in a checkerboard [see illustration, “Easy on the Eyes”]. That pattern was used by General Electric Co., in Fairfield, Conn., in avionics displays in the late 1980s. It made the displays somewhat more efficient, but it had problems. One was that the ratio of colors in the pixels gave the screens a distinct greenish cast. Another was that the scheme could not, for a given density of pixels, render imagery with the highest possible level of detail [see sidebar, “A Sharper Image”].