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High efficiency flat light source could be the end for the light bulb
Gizmag ^ | 4/19/2006 | Staff

Posted on 04/19/2006 10:57:35 AM PDT by Neville72

High efficiency flat light source could be the end for the light bulb

April 19, 2006 The end of the lightbulb is nigh! Scientists studying organic light-emitting devices (OLEDs) have made a critical leap from single-color displays to a highly efficient and long-lived natural light source. The invention is the latest fruit of a 13-year OLED research program led by Mark Thompson, professor of chemistry at USC and Stephen Forrest of the University of Michigan. If the device can be mass-manufactured cheaply - a realistic expectation, according to Thompson - interior lighting could look vastly different in the future. Almost any surface in a home, whether flat or curved, could become a light source: walls, curtains, ceilings, cabinets or tables. Since OLEDs are transparent when turned off, the devices could even be installed as windows or skylights to mimic the feel of natural light after dark - or to serve as the ultimate inconspicuous flat-panel television.

"This process will enable us to get 100 percent efficiency out of a single, broad spectrum light source," Thompson said.

Thompson and Forrest previously invented efficient single- color displays now ready to enter the market in next-generation cell phones. But subsequent attempts by several groups to create white-light OLEDs fell short. The biggest issue was the fast burnout time of the blue component, since blue is one of the primary colors needed to make white.

The Nature paper presents a quantum mechanical trick that solves this problem. First, the researchers followed their standard recipe for making an OLED: placing four ultra-thin organic layers on glass or transparent plastic. Three of the layers serve as highways for charges to reach a central "emissive" layer.

When the oppositely charged molecules meet in the emissive layer, electrons jump from the negatively charged molecules to the positive ones, and ultimately relax to their starting energy. In the process, light is emitted, which can be tuned to cover a broad range of wavelengths.

Previous OLEDs used phosphorescent blue, green and red dyes to generate light with greater energy efficiency than all-fluorescence based devices (phosphorescence and fluorescence, both expressions of energy that is released as excited electrons fall back into their regular orbit, differ mainly in the speed of their response).

Thompson and Forrest found that they could substitute a fluorescent dye for blue without sacrificing the superior properties of OLEDs.

In fact, the researchers reported, the fluorescent dye should prolong the lifetime of the blue component and also uses 20 percent less energy. "We're hoping this will lead to significantly longer device lifetimes in addition to higher efficiency," Thompson said.

According to Forrest, the device eventually could achieve three times the efficiency of standard incandescent light bulbs.

"With a future emphasis on manufacturing technology, this structure may provide an important, low-cost and efficient means that will replace incandescent lighting in many different applications," Forrest wrote.

The tallest remaining hurdle to production of these devices may have nothing to do with the OLED itself, Thompson said, but with the plastic layer to be used as a backing in economical large-area devices. All mass-produced plastics allow some humidity to pass through to the OLED, eventually degrading it.

"There's no plastic that's hermetic enough to make devices that will last a long period," Thompson said, while predicting that this problem can be solved. Already, Universal Display Corp. has developed the group's research into a commercially feasible process for making cell phone screens.

Funding for the research came from the Department of Energy and Universal Display Corp., which holds exclusive licensing rights to the group's OLED inventions.


TOPICS: Miscellaneous
KEYWORDS: leds; lightbulb; lighting; technology
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To: jiggyboy

There's other, IMO more significant advantages over fluorescent lighting- LEDs are far more durable and they do not contain mercury.


21 posted on 04/19/2006 11:25:05 AM PDT by Squawk 8888 (Yay! It's Riding Season!)
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To: Neville72

Yes, but will they make my glass Craftsman style lamps look good? That's my main question.


22 posted on 04/19/2006 11:26:28 AM PDT by Gingersnap
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To: 50sDad

You can get similar products at computer stores- they plug into the computer's power supply.


23 posted on 04/19/2006 11:26:56 AM PDT by Squawk 8888 (Yay! It's Riding Season!)
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To: Professional Engineer
Oooo, all the way up to match fluorescent.

Sure, in commercial applications there's not really an improvement over fluorescent. But I don't use fluorscents in my home because the light quality sucks. If OLEDs provide incandescent quality or better and provide energy savings, then I'll finally switch.
24 posted on 04/19/2006 11:29:30 AM PDT by July 4th (A vacant lot cancelled out my vote for Bush.)
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To: Neville72

An incandescent light bulb is more efficient as a heater than a lighter.


25 posted on 04/19/2006 11:33:32 AM PDT by MinstrelBoy (Welfare shouldn't be a career choice.)
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To: Neville72


26 posted on 04/19/2006 11:34:02 AM PDT by N3WBI3 (If SCO wants to go fishing they should buy a permit and find a lake like the rest of us..)
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To: orionblamblam

> 100 percent efficiency

I'm sure they meant to say 110 percent efficiency. :)


27 posted on 04/19/2006 11:34:25 AM PDT by JeffersonRepublic.com (There is no truth in the news, and no news in the truth.)
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To: Protagoras

Your right if it were not for ben franklin we would still be watching tv by candle light.


28 posted on 04/19/2006 11:37:46 AM PDT by Vaduz (and just think how clean the cities would become again.)
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To: orionblamblam
Yea, nothing better to destroy your credibility with anyone that with much of a scientific background than to claim something is 100% efficient.

These OLEDs are extremely efficient and it's possible that they are closer to 100% efficient than they are to 99% at converting electricity into the visible spectrum. However, it you want to be credible you need to specify the efficiency with enough decimal places to the point where we can see how much less it is than 100%.

It's possible that there's more loss in efficiency in the wiring that is going to the lamp than in the conversion to visible light, but I still want to see the numbers.

29 posted on 04/19/2006 11:42:26 AM PDT by untrained skeptic
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To: 50sDad

The real story here is a transformer that takes 5 volts DIRECT CURRENT to thousands of volts. Heretofore transformers have been Alternating Current only devices.


30 posted on 04/19/2006 11:42:33 AM PDT by knew it all the time
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To: Squawk 8888; jiggyboy
There's other, IMO more significant advantages over fluorescent lighting- LEDs are far more durable and they do not contain mercury.

In traffic signals they also offer redundancy. If one LED in a signal array fails, the rest of them could still be working. With tradtional incandescent bulbs, if the bulb goes out the whole signal is out. A failure to show a red light, can be catastrophic for drivers through an intersection.

31 posted on 04/19/2006 11:42:41 AM PDT by Paleo Conservative
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To: Neville72

Wall sized UHDV screen... Oh my... Yummy.


32 posted on 04/19/2006 11:44:14 AM PDT by Dead Corpse (I believe that all government is evil, and that trying to improve it is largely a waste of time.)
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To: MinstrelBoy
An incandescent light bulb is more efficient as a heater than a lighter.

This is why we are looking into the LEDs. We want good light, just not all the heat. We have enough of that in Texas.
33 posted on 04/19/2006 11:46:39 AM PDT by P-40 (http://www.590klbj.com/forum/index.php?referrerid=1854)
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To: Squawk 8888
The heat that fluorescent and especially incandescent lighting produces also damages fixtures over time and places a lot of limitations on how and where lighting can be placed.

It also makes a building's air conditioning system work harder to offset the heat produced by the lighting when cooling is needed.

This has a considerable potential to reduce the cost of installation, maintenance, and use. At the same time it adds a lot of options for making aesthetic improvements as well.

34 posted on 04/19/2006 11:51:46 AM PDT by untrained skeptic
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To: USFRIENDINVICTORIA
So how will we know if the light is on or off? Will we have to keep a supply of cats around to tell?

As long as you don't let the cat out of the box there is no inconsistency.

35 posted on 04/19/2006 11:54:09 AM PDT by steve86 (Acerbic by nature, not nurture)
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To: All

this is all very fascinating..... i converted to CFL's about a year ago & haven't had to change a bulb yet.

i'm imaginatively hopeful that eventually something similar to this product will cover all interior dwelling wall surfaces in replacement of paint. think of combining futuristic roll up plastic display screens for hdtv with the display changeability of a pc desktop. pc game 3d rendering
engines in conjunction with pc desktop customizability could produce the ultimate interior home decor device.


36 posted on 04/19/2006 11:54:27 AM PDT by Psalm_2 (1776 - !?? Dec. 7th 1941. Sept. 11th 2001. Never Forget. proud son of Pearl Harbor Survivor.)
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To: 50sDad
Efficiency? We have LED lanterns that will run continuously on four D cell batteries for 17 days on 15 LED mode or 8 days at 30 LED mode. These lanterns are super bright.
37 posted on 04/19/2006 12:06:01 PM PDT by Ursus arctos horribilis
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To: knew it all the time
The real story here is a transformer that takes 5 volts DIRECT CURRENT to thousands of volts. Heretofore transformers have been Alternating Current only devices.

Two words: Nikoli Tesla.

38 posted on 04/19/2006 12:10:11 PM PDT by 50sDad (ST3d: Real Star Trek 3d Chess: http://my.ohio.voyager.net/~abartmes/tactical.htm)
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To: untrained skeptic
It also makes a building's air conditioning system work harder to offset the heat produced by the lighting

Especially if you use halogens! Ouch!
39 posted on 04/19/2006 12:20:25 PM PDT by P-40 (http://www.590klbj.com/forum/index.php?referrerid=1854)
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To: July 4th
"I don't use fluorscents in my home because the light quality sucks."

You probably have that opinion because the good fluorescent lamps aren't usually available at your local hardware store.

Two thing to look for: Look for a lamp that scores at least 80% on the color rendering index. Also look for a lamp that is rated at least 5000 degree Kelvin on the color temperature index.

These minimal specs will give you a high quality color-corrected light. (If color rendering is important for your application, look for true "full spectrum" lamps: 91% CRI and 5900 degree Kelvin.)

40 posted on 04/19/2006 12:21:38 PM PDT by 2111USMC
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