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Organic LED Could Replace Light Bulbs?
Posted by
Zonk
on Sat Apr 15, 2006 05:32 AM
from the heard-that-before dept.
from the heard-that-before dept.
egrinake writes to mention a BBC article about a 'natural' replacement for lightbulbs. From the article: "The organic light-emitting diode (OLED) emits a brilliant white light when attached to an electricity supply. The material, described in the journal Nature, can be printed in wafer thin sheets that could transform walls, ceilings or even furniture into lights. The OLEDs do not heat up like today's light bulbs and so are far more energy efficient and should last longer."
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Good Idea... (Score:5, Funny)
Re:Good Idea... (Score:4, Insightful)
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Re:Good Idea... (Score:4, Funny)
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Re:Good Idea... (Score:3, Funny)
A: Only one, but you'd have to put an awful lot of voltage across him to get him to glow properly.
Obvious Safety Application: (Score:4, Interesting)
Re:Obvious Safety Application: (Score:5, Funny)
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Re:Obvious Safety Application: (Score:5, Funny)
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You can do that already. (Score:3, Informative)
In clothes (Score:5, Funny)
Well, I suppose the Tron Guy [tronguy.net] is going to have a field day with this stuff, so it's not all gloom and doom...
Advertisements (Score:2)
Re:In clothes (Score:4, Funny)
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Everyone will steal them for the platinum (Score:4, Interesting)
It's a story of USC and UDC (Universal Display Corp. near Princeton U)
Though it seems they need to make sure it doesn't get wet, and looks like a target for thieves who want the platinum or iridium in every molecule..
Interesting that one article says current incadescents are 15 lumens/watt (true?) while OLED is now at 20 with potentially 60 l/w in near future. I thought those led/dry cell driven pocket torches produced 30 lumens though..
google keys: Professor Mark Thompson of the University of Southern California oled
Re:Everyone will steal them for the platinum (Score:5, Interesting)
as far as I can tell, that is marketing bullshit.
I have a LED headlight for my bicycle and while it is very intense when its pointing right at you, it has very poor illumination capability when compared to an incandescent headlight. The light is very directional so when they say 'X lumens' it generally means they measured the output in the beam segment rather than the the whole sphere.
For town riding, such a headlight is fine. You arent using it for its illumination, you really only want a light so cars can see you, and if you are riding into oncoming traffic at night chances are you are a fool. The rear light is generally more important. In the country where streetlighting is non existent, the LED is barely adequate and you need an incandescent bulb.
I can't be bothered to google for references to back my shaky claims up, its just a personal anecdote.
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stupid energy noob question (Score:2, Insightful)
It seems to me the more heat I produce from my bulb/processor, the less my temperature regulator will pull energy from my heating system (based on gas, which is becoming more expensive). What's wrong with this way of thinking ?
Re:stupid energy noob question (Score:5, Insightful)
There's an extra layer of inefficiency. If you heat your house by burning gas, you get nearly perfect efficiency: almost every joule of heat liberated by the chemical reaction goes into your house, with a relatively small amount of waste heat going up the chimney; modern boilers are very efficient indeed at getting every bit of heat they can.
If, OTOH, you heat your house by electric current - i.e. by the waste heat from your electrical devices - then somewhere in the world there's a power plant burning gas on your behalf. That plant converts gas to heat at higher efficiency than your boiler, but then wastes energy in the conversion to electricity, and then even more is lost in transmission to your home.
So, if you switch to more economical lighting, your boiler will have to burn a little extra gas because you're no longer getting the heating effect of old-fashioned incandescent lightbulbs. But that's more than offset at the power plant, where they have to burn less gas because you're consuming less electricity.
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Re:stupid energy noob question (Score:5, Insightful)
The above statement assumes that you live in a place where heating is the main problem for indoor environmental control. I'd like to point out that for folks between the Tropics of Cancer & Capricorn or respectively just above, or below them heating is not the problem, cooling is.
Here in East Texas we're already running our air conditioners and it's only April. The reason for this is not that it's all that hot, but to dehumidify the air in our homes, offices, etc.. I've lived in Texas for all my 40 plus years. Normally we have more than ten days of 100 degree F. or greater being our daily high temperature. Late July, and all of August, plus the first half of September can produce some real scorchers. The use of high efficiency lighting, helps reduce the power consumption at home, office, etc. in two ways. First, it simply use less Joules to produce a given amount of lumens of light, second it reduces the amount of waste heat that the AC must deal with. So, you save on the cost per lumen of light, and you save on the cost of AC that is used to rid the indoor environment of the wast heat.
I've noticed that many of the post here on slashdot have a 'high latitude/left coast' bias on energy issues. Can't imagine why.
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Re:Double duty (Score:3, Interesting)
It generally doesn't, because of the conversion and transmission losses. Heating by electricity is more expensive than heating by gas, because the power plant has to burn more gas to supply that electricity than you would have had to burn yourself to heat your hom directly. If gas prices were to rise, then electricity prices would rise along with them (and have been doing just that).
However, i
Re:stupid energy noob question (Score:3, Informative)
2. Heating allows for fine tuning of the temperature.
3. In the summer, the excess heat from the light bulb must be negated by your cooling system, causing even more energy drain.
Re:stupid energy noob question (Score:3, Interesting)
In an ideal world, you wouldn't be using neither gas, oil, nor electricity for heating your house (at least not as the main source). There are plenty of more environmentally friendly heat sources available, like heat pumps, wood, solar power and so on.
Also, in case you don't live in a
Finally, a use for IPv6 (Score:5, Interesting)
Hmm, interesting possibilities...
Re:Finally, a use for IPv6 (Score:5, Funny)
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economy (Score:4, Informative)
And... do not compare it to traditional light bulbs. Traditional light bulbs are dead.
Of course, LEDs have achieved a lot in producing more and more light, but currently it is some 10s or 100s fold differends between the price of the
fluorescent light sources and a LED based one, and the fluorescent light source (mostly) produces more light than the LED.
Yes, I hope that OLEDs will be the ones who can reach the barrier, but until that this article is very-very optimistic
check
(figure:)
http://europa.eu.int/comm/energy_transport/atlas/
articles:
http://europa.eu.int/comm/energy_transport/atlas/
http://www.lumileds.com/pdfs/TP40_IESNA_July%2020
Re:economy (Score:3, Informative)
Actually, this isn't anything new. I've known about it for several years now. Nice to see it finally clawing its
100% efficient (Score:4, Insightful)
OLED vs LED (Score:3, Informative)
LED's are improving much faster - 100Lm/W from Nichia to hit market soon:
http://www.eetimes.com/news/latest/technology/sho
This article is crap. (Score:4, Interesting)
#1, they're too expensive. Compact fluorescents - which are are a 4x efficiency gain over incandescents - are only just starting to catch on now that they're under $2.
#2, the color rendering sucks. You know how old fluorescents used to made you look undead? LED's suck even more.
So, instead of addressing either of those hard issues, they give us an article full of: "The researchers believe that eventually", "Before this becomes a reality", "If that barrier can be overcome", etc. Thanks for the fluff.
Also, I'm not normally a grammar nazi, but for the love of god, 23 sentences:21 paragraphs is a ratio to be ashamed of.
Re:This article is crap. (Score:3, Interesting)
You can make LED sources with high CRI (colour rendering index) if you combine six or seven LED colours together. An ex-colleage of mine made one with a 95+ cri.
Re:This article is crap. (Score:4, Informative)
First of all, PLEDs (that's POLYMER based light emitting diodes) are a liquid, so they can actually be printed using existing inkjet technology - it's incredibly cheap to manufacture because you don't need special equipment, just modify existing plants. Instead now of printing paper, you're printing lightbulbs/screens.
Secondly, each of these is minutely small. The emissive layer is LIQUID. The resolution is absolutely fantastic, just as good as liquid crystal.
Thirdly, LCD screens are dependant upon polarisation. You have a really strong backlight, you pass currents through the liquid crystal layer and it blocks out certain frequencies of light. No matter what you show on screen, whether it be completely black or completely white, it's consuming the same electricity, it's just that in one, the liquid crystal is letting you see it, in another it's not. Have you ever wondered why the screen gets its darkest ONLY when you turn it off? That's because the backlight gets turned off. OLEDs naturally produce the light from the off, and only use the energy required to make the frequency you need. Not only does this mean you get a more natural colour, you get REALLY good contrast because you can render black properly.
Forthly (I should really stop this list): because you can tailor make a film of OLED to produce a particular frequency of light, it WILL look natural. If you're asking why, think back to some basic physics - you remember that when an electron descends an energy level, it emits a particular frequency of light? The sun has a pattern of frequencies produced this way, but it's with hydrogen, which is quite hard to replicate, with say, neon and flourescant bulbs. With OLEDs it's easy to tailor make molecules that'll replicate the same frequency spectrum.
I had to do a presentation about OLEDs a few months ago mate: I know my salt.
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Re:This article is crap. (Score:5, Informative)
Your 4th point is simply wrong. The sun emits light as a dark body, and it is a very hot dark body. It is hard to emulate the sun light with LEDs because LEDs have a very narrow emission spectrum, and a dark body's emission is continuos. Also, because the sun is very hot, it emmits light at very hight frequencies (blue and violet), that are hard to abtain on LEDs.
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Don't Get It Wet (Score:5, Funny)
If only they could put it into an airtight package, something small and convenient, maybe a
longevity of light bulbs (Score:4, Informative)
Re:longevity of light bulbs (Score:3, Insightful)
Last scene in 2001 (Score:3, Funny)
Sounds like Dave Bowman's bedroom in the last few minutes of 2001. (Too bad we can't post pictures here... thanks again "goatse.cx" commies for ruining things.)
Yeah but (Score:5, Funny)
People like sunlight (Score:3, Insightful)
Yes, but does it create a nice black-body spectrum curve like conventional light bulbs?
Most people like warm cross-spectrum light because it resembles sunlight, I didn't RTA but 'a brilliant white light' sounds like fluorescent to me. Not a very 'natural' alternative.
Re:People like sunlight (Score:5, Insightful)
theres also many types of fluorescent bulbs. the film industry uses daylight balanced fluorescent quite a bit now because you can have a continuous light source without all the extra heat generated by the incadescents.
in any case, regardless of what the color spectrum is, it is easy to color filter a brilliant white light.
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Simple fix: gene-mod bacteria to contain OLEDs (Score:3, Funny)
Then we'll have to invent artificial darkness to get away from the everpresent glow.
Re:Quick, bury it! (Score:2, Interesting)
For instance, the *power companies* buying the patents and shelving them.
That's also bunk, but it at least has a hint of financial incentive to it.
Re:Quick, bury it! (Score:5, Insightful)
Because if they could do this, they'd have already done it for fluorescent tubes, which can be up to about 60% efficient (compared to 10% for incandescent bulbs)?
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Re:Quick, bury it! (Score:3, Interesting)
Re:Quick, bury it! (Score:4, Insightful)
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Re:Quick, bury it! (Score:3, Informative)
Hemp is even cheaper and more readily renewable than wood. Personally I think it makes higher quality paper. Why doesn't the US smarten up and start pushing this as an alternative to clear cutting acres and acres of land. It also makes an excellent rotation crop because of the lack of pests.
Re:Quick, bury it! (Score:3, Funny)
Re:Quick, bury it! (Score:5, Insightful)
IF all of those things are true, then let a bunch of lightbulb manufacturers conspire not to produce it! All it takes is one who's willing to produce it, who can then start reeping huge market share (to meet the assumed customer demand). Heck, it could be you. If all of the above things are true, then you could come in and make a killing on this thing even if every single lightbulb manufacturer chooses not to. And as soon as you do, every manufacturer who "conspired" not to produce this will be forced to in order to chase after those profits that you're getting.
If any one of those assumptions above is false, then it does not require a conspiracy to prevent widespread production of this product. The most likely assumption that's false is #4, but it could be any of them. In any case, if we don't see OLEDs dominating the lighting market, will you simply conclude that it was a secret conspiracy or that maybe one of your upfront assumptions was false? My recommendation would be to apply occam's razor.
$.02
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Re:Quick, bury it! (Score:5, Informative)
It's much more down to earth: there's a simple relationship between light yield and lifetime (from wikipedia [wikipedia.org]:
- Light output is approximately proportional to V^3.4
- Power consumption is approximately proportional to V^1.6
- Lifetime is approximately inversely proportional to V^16
More light for your watt means the bulb burns out more quickly. They are now tuned for 1000 hours, which -mind you- means about $10 in electricity during the lifetime. If you want to increase the lifetime, put it on a dimmer.Parent
Re:Quick, bury it! (Score:4, Insightful)
Which gets us to the real reason light bulbs don't have drastically longer lives... tuning a light bulb so it has a longer life means that it has significantly lower energy efficiency. Those "long life" light bulbs you see in the supermarket usually end up costing you more in the long run. They do make some sense to use them in a situation where they are difficult or even dangerous to replace, but then you would be wise to consider compact flourescent as they last VASTLY longer and use significantly less energy. And that "bad light" and "flicker that makes people sick" is pretty much an artifact of the past. Newer tubes and bulbs have much cleaner light.
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Re:Quick, bury it! (Score:3, Informative)
The main reason is that the power supply can be much smaller when running at 10 kHz or so compared to 50 Hz. In the latter case, it is a ballast in series with the tube, consisting of a big and heavy induction coil. In the former, it is more like a switching power supply. More expensive components (at least if you only need to convert a few watts), but also much smaller. RF can mean anything between 3 Hz and 3 [wikipedia.org]
Re:Quick, bury it! (Score:5, Informative)
Obviously we're worried somebody else will take away our lighting market share by bringing out the killer-led-app. However, there's no question of "buying up IP and sitting on it". This playing field is as open as it gets in the industry.
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Actually what I see happening is (Score:5, Interesting)
1. Putting out all sorts of products using OLEDs, expanding beyond what we conceive of light being used for
2. Putting out specialty incadescents/flourescents that fill the gaps in the first
If anything this expands their market and an innovative company will take off. Not all lighted items need to provide illumination that is bright enough to read by. A lot can be done with highlights, accenting areas with different shades and such. Accent lighting will be a big, replacing LEDs that are currently trying to edge into that market. All the business uses will help as well. It would be far much easier to use these for instore billboards than the flourescent lit displays so common today.
Now another area is backgrounds. Better for business use than home, though some may use it in homes. Can't imagine my home looking like 1999's moonbase but I can see walls in certain types of businesses where the whole area is covered and changed in color for events and such.
Lighting products are not all about letting you see things, some exist to be seen
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Re:OLED vs LED (Score:4, Informative)
No, LEDs work by using a voltage to push charge carriers in a semiconductor diode above the "bandgap" of the diode (the energy level at which the diode starts to conduct, which is determined by the type of semiconductor material used).
One part of the diode has positive charge carriers, the other has negative charge carriers, like so: +V ---{ p | n }--- V- Because like charges repel, the positive voltage pushes the positive charge carriers to the p-n junction in the center and the negative voltage also pushes the negative charge carriers to the p-n junction. The energy released when the positive and negative charges combine in the p-n junction comes out as light of a frequency (color) determined by the bandgap voltage.
This is a quantum process: Energy = Planck's constant * frequency (or E = h*f, often written E=h*v - that's a nu, not a v).
Sparks require a voltage that is higher the farther apart the electrodes are, and the highest frequency light produced does depend on the voltage, but sparks produce broad rather than monochromatic spectra with energy emitted down to very low frequencies.
**
As an aside, one can measure Planck's constant using LEDs:
Since the energy per charge carrier is the voltage times the charge (Electron-volts, which can be converted to Joules by multiplying by the factor coulombs per electron, 1.6E-19) and the wavelength is known from the manufacturer's data sheets and can be converted to frequency by:
frequency(Hz, 1/s) = speed of light(3E8 m/s) divided by wavelength(m, usually listed in nm = 10E-9m), given LEDs of known frequencies one can measure Planck's constant.
h = E/f = [V*(1.6E-19 Coulombs)*(wavelength in nm)*(1E-9 m/nm)]/(3E8 m/s) or
h (in Joule-seconds) = 5.3E-37 giga-coulomb-seconds * voltage * wavelength in nm.
Other factors make this an inaccurately low measure - the voltage needed to light the LED is lower than E = hf would indicate. (Perhaps it's the high energy tail in the distribution of thermal electron energies?)
A potentially more accurate way to get h is to note that in E = h*f, when E is graphed against f, then h is the slope of the line. Variations in eye sensitivity and LED efficiency also introduce inaccuracies here, but green and orange LEDs seem to give a slope very close to the correct number.
(Also note that you need single-color diodes - the "yellow" diodes commonly found are really red+green in a single package.)
See CERNs page on Jules Hoult's high school lab lesson plan [web.cern.ch]:
lab sudent worksheet [web.cern.ch]
results results graph [web.cern.ch]
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