Fred Maxik wants to make a light bulb that will help you sleep.
"Biological specific lights,” tuned so as not to interfere with an individual’s normal production of melatonin, the hormone secreted from the pineal gland linked to sleepiness, could begin to hit the market in about two years, according to Mr. Maxik, a founder of the Lighting Science Group, which specializes in LED bulbs.
With a biological bulb, you could read at night without experiencing the nagging irritability that can occur after using a computer or sitting close to a lamp near bedtime.
And other bulbs — or the same bulb programmed via a network— could help make consumers feel more refreshed in the morning by choreographing their wake-up ritual. “We could even do things like lights for sterilization, with photo catalysts” for bathrooms in perhaps five to six years, he added.
While solid state lights and LED bulbs have been promoted as a tools for energy conservation, industry experts and executives suggest that efficiency will become a Trojan horse for a host of unexpected and arguably more valuable applications. Light-emitting diodes, after all, are semiconductors that can be programmed to emit light at precise wavelengths, colors and tones. Traditional light bulbs, the last vestige of the vacuum tube era, produce light with hot gases or wires.
Greater control over light would ideally lead to greater control over the surrounding environment, researchers suggest. “Light has these biological and behavior effects — why not build on it?” said George C. Brainard, a professor of neurology at the Jefferson Medical College at Thomas Jefferson University and one of the leading researchers in the field.
Dr. Brainard predicts that over the next decade or two, health benefits will come to be considered one of the primary attributes of bulbs along with energy consumption, aesthetics and brightness. He and Lighting Science are working with NASA on LED lights that are intended to allow astronauts to better adjust to phenomena like the 90-minute “days” experienced on the orbiting International Space Station.
Boeing included LEDs in the cabin of the new 787 Dreamliner that dim and increase in intensity to slightly adjust the circadian rhythms of passengers on transcontinental flights. The hope is that it will help passengers more easily adjust to jet lag.
Meanwhile, researchers at Japan’s Keio University and elsewhere have experimented with LED traffic lights and car taillights that emit photons in pulses like optical fibers. While humans can’t visually perceive the difference, the pulses serve up a data stream about traffic conditions or potential accidents.
"An LED is a light source, but it is an infinitely controllable source,” said Zach Gentry, an executive at enLighted, a company that combines LEDs with temperature, light and occupancy sensors to produce a device that monitors energy consumption and physical activity in office buildings. EnLighted just raised $14 million in capital.
The National Institute of Mental Health discovered the connection between light and health in 1980 in an experiment that showed bright white light could suppress melatonin production. A few years later at Harvard, scientists demonstrated that circadian rhythms could be disrupted.
Then in 2001, Dr. Brainard found that circadian rhythms could be disrupted with fairly low levels of blue light. He and others concluded that the eye must have undiscovered photoreceptors sensitive to blue light that perform nonvisual functions. It was a somewhat radical notion, but a year later, scientists at Brown University and Johns Hopkins physically isolated the receptor.
Light therapy is already used to treat seasonal affective disorder and premature infants. The Lighting Research Center at the Rensselaer Polytechnic Institute has noted associations between disruptions in the natural light-dark cycle and increased incidents of insomnia and breast cancer.
Traditional light sources can have the same physiological impact. LEDs, however, are easier to control. More important, the physiological effects can be triggered with comparatively low levels of blue light, which LEDs emit natively.
White light LEDs are actually blue LEDs covered by a yellow phosphor. Tinkering with the phosphors or combining blue and “white” LEDs in the same bulb could result in a somewhat more economical, compact “health” bulb.
While mood lighting for ordinary consumers remains a few years out, the public has already begun to experience some of the hidden benefits of LEDs. Many upscale retailers have installed LEDs to achieve special lighting effects or to make jewelry cases sparkle. Subway, the sandwich chain, is installing LED fixtures from Lunera Lighting in some outlets to enhance their appearance.
"You can create a color perspective that makes people look good,” said Don Peifer, one of the company’s co-founders. Before starting up Lunera, which specializes in LED fixtures that evenly “wash” offices and lobbies with light, Mr. Peifer worked as a lighting designer for photographers like Annie Leibovitz and Steven Klein.
Lunera has also installed fixtures in eBay’s data centers that eliminate vertical shadows in computer racks.
Redwood Systems, another Silicon Valley start-up, and enLighted are combining LEDs with temperature and occupancy sensors to help retailers determine whether consumers stop at certain aisles and whether check-out lines are growing shorter or longer.
Humans and artificial lighting have never been an ideal combination. Circadian disorders result from placing humans in unnatural situations. “Before the Industrial Revolution, people worked in fields,” Mr. Peifer said. “There was a really strong dichotomy between night and day.”
Maybe LEDs can restore some of the balance. “We don’t know what will happen in the future of lighting, and that is the exciting part of it,” Mr. Peifer said.
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