Blue LEDs have become particularly popular for electronics_00002

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"It lights up like the Fortress of Solitude," Therrien's said, likening itto Superman's
headquarters of glowing crystals. He

tamed it with 12strips of black tape.
Tom Hespos, a partner in an advertising firm in New York, countedsix glowing
devices in his bedroom. One is an alarm clock

with ablue backlight so strong he has to put a pillow between it and him.
And don't get him started on his Internet router, which hasblinking blue light-emitting
"Whoever sees that glow through my window must think I'm keepingaliens in my
spare room," he said.
Blue LEDs have become particularly popular for electronics, andthat's part of the
problem. In dim light, our eyes are

moresensitive to colors at the blue end of the spectrum, so blue LEDslook brighter,
said Mariana Figueiro of the Rensselaer

PolytechnicInstitute's Lighting Research Center in Troy, N.Y.
When blue LEDs became available in 1993, following red, green andyellow, they first
showed up only in high-end equipment.
Andy Logan, principal designer at Frog Design in San Francisco,tries to steer
manufacturers toward more subtle light

designsrather than having the diodes shine like flashlights.
But he doesn't recommend designing products so that people can turnoff the lights
without turning the entire gadget off. The

lightsoften indicate when a device shouldn't be unplugged, such as when ahard drive
is writing data.
Outside the bedroom or dorm room, more blue LEDs might actually bea good thing '
researchers are exploring whether they can

beused to keep people alert and awake.
Scientists have discovered that a light-sensitive layer of the eye,separate from the part
that allows us to see, sends

signals to thebody that affect rhythms of wakefulness and sleep.
That layer is also more sensitive to blue light than to any othercolor, said George
Brainard, director of the light research

programat Thomas Jefferson University in Philadelphia.
He has funding from the NASA-affiliated National Space BiomedicalResearch
Institute to study whether blue-light treatment can

helpkeep astronauts more alert. Figueiro is helping the Navy figure outwhether blue
light can help submariners adjust to

their watchschedules.
For now, researchers don't believe the low levels of blue lightemitted by gadgets is
enough to change our sleep patterns.
"Some paid, "so I'd hateto say never."


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