Newswise — At least throughout the developed world, people take for granted that they will have access to electric lighting at home, in schools, and on the job. Its synthetic sunlight allows people to work and play anywhere, at any time. In the first of a two-part series, Janet Raloff at Science News magazine describes how the lighting industry is rapidly embracing digital technologies. Within a decade or two, she reports, today's incandescent and fluorescent lights could become as antiquated as the vacuum-tube radio. In part two of her series, researchers describe new insights on how light interacts with the body—to perk up attention, improve visual acuity—even reduce depression. In short, the new data show that for the body, light's role extends well beyond vision.
Today's lighting depends on technological dinosaurs, technologies that have changed little over the past century. Though reliable, these technologies are energy hogs that consume huge amounts of power. In the United States alone, some 22 percent of the nation's electricity powers lighting. Pollution associated with that lighting is also enormous.
New strategies are emerging to shrink lighting's economic and environmental footprints. Some advances make fluorescent lighting more efficient—by dimming it when sunlight is abundant or during those periods of the day when utilities spike the rates they charge for electricity. Other technologies look to bring sunlight into buildings—such as through optical fibers that are tied into conventional ceiling fixtures.
However, purely digital technologies promise to usher in far bigger energy and environmental savings. Light emitting diodes, or LEDs, for instance, are already available in a range of products, such as automobile tail lights. Such LED systems haven't, however, been able to substitute for a table lamp or ceiling fixture. But prototype systems indicate that LED room lighting may not be far off. Science News describes the first commercial, high-intensity LED desk lamp for commercial settings, and university-designed prototypes of interchangeable room lights illuminated solely with LEDs. Not only do the latter draw little power, but the low-voltage systems can be powered off the grid—by rooftop solar collectors or wind power. And the color they emit can be tuned at will to whatever a consumer wants—white for reading, red or maybe green on holidays, even a continuously varying spectral output.
However, less sophisticated lighting needs by people in the developing world may be what actually propels a rapid introduction of LED systems, Science News finds. Today, the 1.6 billion people who live without electricity usually depend on liquid fuels, such as kerosene, for lighting. However, a 2-watt, battery-powered LED lamp could provide lighting that surpasses the output of liquid-fuel lamps—and pay for itself in less than a year.
In part II of her series, Raloff describes the emerging data on how light can signal—or even trick—the brain's biological clock and other systems of the body. Such findings suggest that by tailoring its timing and color, lighting can become therapeutic.
Blue hues appear most effective at resetting the body's internal clock—a system that sets sleep and wake cycles. Although the eyes relay the spectral cues, their most sensitive receptors are not related to vision.
Based on these new findings, blue-light therapies are now under investigation. Raloff reports that they already have begun to show promise in helping people who suffer from winter depression and the disordered sleep associated with dementias. Blue light may even operate like spectral caffeine, depending on when it's delivered, to maintain alertness and ward off sleep. In some instances, Science News notes, blocking the eyes exposure to blue light—using filters—can prevent the inappropriate arousal of teens who have trouble falling asleep.
The findings are leading to new prototype systems, termed dynamic lighting, that vary a lighting fixture's spectral output during the day. The goal: illumination that not only enhances productivity, but also mimics the natural cues our bodies have come to expect from sunlight about when it's time to work or rest.
Part I is available at: http://www.sciencenews.org/articles/20060520/bob9.asp; Part II is available at: http://www.sciencenews.org/articles/20060527/bob9.asp
RSS