LED Lights Shine In Nobel Prize; Now How About Your Home? | KERA News

LED Lights Shine In Nobel Prize; Now How About Your Home?

Oct 7, 2014
Originally published on October 8, 2014 1:24 pm

The Nobel Prize in physics was awarded Tuesday to three Japanese-born researchers for their work on the blue light-emitting diode, or LED.

And there's never been a better time to put their Nobel-prize winning discovery right in your own home. LED light bulbs, which use blue LEDs, are coming of age, and the price is dropping fast. You can pick them up for less than $10 each.

It's been a long, hard road for the LED. The first were the red ones that have been commonly used for decades as power indicators on stereos or appliances. Then came green and yellow, but researchers couldn't find a way to make blue — until Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura came along.

"They got a material called gallium nitride, which emits blue light, [and] they got it to work," says Colin Humphreys, an LED researcher at Cambridge University in the U.K.

Akasaki, Amano and Nakamura coaxed gallium nitride to glow bright blue. Industrial researchers added a layer of phosphorous around the blue light, and that made brilliant white light.

After two decades of careful tweaking, LEDs are becoming commonplace as light sources for homes and desk lamps. LEDs even light your laptop computer's screen.

"It's important they won, because the science they've done is really useful science," Humphreys says.

The new LED lights are around seven times as efficient as conventional light bulbs and about twice as efficient as compact florescent bulbs. That means big energy savings.

"It's just huge — worldwide we could close or not build over 500 large power stations," if everyone used LED light bulbs, Humphreys says.

So the Nobel makes it official. LEDs are great for the planet and your wallet. But there's another problem: Which LEDs should you buy?

"Oh golly, that's a really tough question to answer these days with all of the different kinds of bulbs on the market," says Bob Karlicek, director of the Smart Lighting Engineering Research Center at Rensselaer Polytechnic Institute.

Karlicek says there are two things to look for. First, you need to think about something called "color temperature." It describes the type of light the bulb produces.

"I think you want to take a look at bulbs that are warm white, which means that they should have a color temperature of 2,700 Kelvin," he says.

The other big attribute is brightness. LEDs measure brightness in something called lumens, and 800-900 lumens equals the brightness of a conventional 60-watt bulb.

You can find a lot of other tips on buying LEDs and other energy efficient bulbs by checking out NPR's guide to changing light bulbs.

Copyright 2017 NPR. To see more, visit http://www.npr.org/.

MELISSA BLOCK, HOST:

The blue LED or light emitting diode has illuminated the way to a Nobel Prize for three Japanese-born researchers. They are Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura. As NPR's Geoff Brumfiel reports, you can put this Nobel prize-winning discovery to work right in your own home.

GEOFF BRUMFIEL, BYLINE: I've got two desk lamps in the studio with me. The first one has a good old incandescent light bulb. And the other one - let me just switch that one on. The other one has just won a Nobel Prize. It uses something called a blue LED. LEDs that aren't blue have been around for decades. Red ones are commonly used as power indicators on stereos or appliances. Researchers have also made green and yellow. But they couldn't find a way to make blue until these three scientists came along.

COLIN HUMPHREYS: They got a material called gallium nitride, which emits blue light. They got it to work

BRUMFIEL: Colin Humphreys is an LED researcher at Cambridge University. Once they made a blue LED, other researchers put a phosphorus layer around it to produce brilliant white light. That's what's finally allowed LEDs to be used as light sources for homes and desk lamps. LEDs even light your laptop computer screen.

HUMPHREYS: It's important they won because the science they've done is really useful science.

BRUMFIEL: The reason blue LEDs are taking over goes back to the two lamps I just switched on.

HUMPHREYS: If you put your hands on the incandescent light bulb, it'll probably burn your hand.

BRUMFIEL: Let me try that.

HUMPHREYS: Do try that. Yes.

BRUMFIEL: Ow.

HUMPHREYS: OK, right? That's not...

BRUMFIEL: If you leave it there, it's not a good idea.

HUMPHREYS: Not a good idea - and that's why. An incandescent light bulb works by passing current through a heated wire filament. And this wire then glows white-hot and it gives out white light.

BRUMFIEL: But that light is only 5 percent of the energy. The rest is wasted as heat. LEDs are much more efficient. I'm touching it right now and it's just a little warm. That means LEDs save lots of energy.

HUMPHREYS: It's just huge. Worldwide we could close or not build over 500 large power stations.

BRUMFIEL: If we used LED light bulbs. So the Nobel makes it official. LEDs are great for the planet, for your wallet - go get them. But have you been to a hardware store? How do you decide what to get?

BOB KARLICEK: (Laughter) Oh golly, that's a really tough question to answer these days with all of the different kinds of bulbs on the market.

BRUMFIEL: Bob Karlicek directs the Smart Lighting Engineering Research Center at Rensselaer Polytechnic Institute. There's two things to look for. First, Karlicek says you need to think about something called color temperature. It describes the type of light the bulb produces.

KARLICEK: I think you want to take a look at bulbs that are warm white, which means that they should have a color temperature of 2,700 Kelvin.

BRUMFIEL: Then there's brightness. LEDs measure brightness in something called lumens - 800 to 900 lumens equals the brightness of an old 60-watt bulb. Good bulbs go for $10 or less these days. So bottom line, you may want to think about picking up a couple of these Nobel winners yourself. Geoff Brumfiel, NPR News. Transcript provided by NPR, Copyright NPR.