\'Tunable\' light bulb could improve sleep

Light bulbs from the Netherlands will not only illuminate a room but could help users concentrate, relax, read or even improve sleeping habits, experts say. Philips Electronics has launched the Hue bulb, containing red, green and blue LEDs that can be tuned using a smartphone or tablet to fill a room with light from pure white to almost any color, NewScientist.com reported Friday. While Philips is marketing it as a fun technology, experts say it has intriguing possibilities for improving the lives of its users. Research has shown that different colors of light affect a set of receptors in the eyes that respond to blue light by suppressing production of sleep-inducing melatonin, keeping people awake and alert during the blue-rich light of daytime, while reddish evening light allows people to ease into sleep. Fluorescent bulbs contain a lot of blue light, so being exposed to them late in the day or at night can contribute to sleep problems. Many LED bulbs perpetuate the problem, because they generate white light using blue LEDs coated in compounds that emit longer wavelengths when illuminated. NASA is developing color-tunable lights for the International Space Station because astronauts have trouble sleeping more than 6 hours a night. The NASA bulbs are designed to switch from blue-rich to keep the astronauts alert during their working hours to red-rich light when they are preparing for their sleep periods. Philips says studies show students perform differently in school rooms illuminated by different types of lighting -- a red-rich \"relax\"; a blue-infused \"energize\"; a milder, yellowish \"concentrate\"; and a \"reading\" blend.