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Perfict light source invented
croxis
I am the walrus
in Zocalo v2.0
[url]http://www.vnunet.com/vnunet/news/2154049/perfect-power-source-invented[/url]
Comments
One challange state was that the lighting membrane must no be exposed to humity and that all plastic allow some exchange of mositure. In non-flexible situations, it would seem that glass would provide a suitable backing.
Jake
Although wouldn't some plastic panels work just as well?
[B]Now keep in mind that using glass would make it either very heavy, very fragile, very expensive to make, or any two of the above. For a mass-market light source, that's not good mojo. [/B][/QUOTE]
Yes, and current incandescent and flourescent lightbulbs are not fragile in the least...
[B]Thats why we now have transparent aluminum! [/B][/QUOTE]
Hello computer!?
[B]Yes, and current incandescent and flourescent lightbulbs are not fragile in the least... [/B][/QUOTE]
But incandescent bulbs are typically small, contained either in small modules under 4" wide (powered within the larger reflectors that hold them) or a formfactor that can be held in no more than two hand (such as standard incandescent) (though I never said I thought standard screw-in bulb varieties were good :p)
Even fluorescent tubes are pretty resilient until they get to lengths above three feet, but it's because they're cylindrical. On top of that, they're usually contained in a larger reflector behind a fresnel or parabolic lens.
From what I've read on this light source, it would likely be somehting that would be best applied in an area larger than a 12" x 12" square, and would be of relatively little thickness purely by its nature...i.e. a traditional-mounted fluorescent light fixture but just the bottom-most lens.
Transporting these with a lightweight/thin glass shell could be a costly mistake unless a foolproof storage system was devised. But even then, it would need to survive the initial installation attempt (probably not difficult, but potentially more so than the simple twist-in fluorescent or clip-in halogen) and be friendly to some minor form of flex and maintenance (as unlike a tube, it would have to If built to withstand such environmental factors, it would have to be a good deal heavier and therefore more expensive due to the additional glass needed to make it. it's only a little bit, but every couple of cents, and every couple of ounces add up when you're buying hundreds or thousands.
Anyway, yeah. I think that's coherent.
[B]Hello computer!? [/B][/QUOTE]
:D priceless
[B]Perhaps I'm missing something, but why would it have to be transparent? Back it with a sheet of steel and strap it to the ceiling. [/B][/QUOTE]Both sides of the monitor? It won't be a monitor after that. :)
[B]Perhaps I'm missing something, but why would it have to be transparent? Back it with a sheet of steel and strap it to the ceiling. [/B][/QUOTE]
The issue is, it needs to be hermetically sealed, as the material has no tolerance for moisture. Having a metal backing means there must be a seal on one side of it (unless you mean metal behind the glass frame, which could be done...but would be another expense)
The best part is that its 100% effiecent, every bit of energy is converted to light, rather than heat.
Jake
[B]There are lots of materials you can use as a backing, and it's not hard to seal a glass plate into a frame with backing and OLEDs in between. It's not going to be flexible, so the seal won't be put under stress and break. [/B][/QUOTE]
This is all true. However, this still leaves one glass panel to deal with, and also has to ensure that there will be *absolutely* no long term leakage. And obviously, they've felt that glass was not an option, or they would have used it, anyhow.
Though, I'd really like to find some more details on the material. The article linked to is so painfully vague.
It's just such a neat sounding technology!
Because it's slopily made... for example, quoting "Thompson" without bothering to give full name and affiliation before... as if they just cut parts out of a news release without bothering to re-write the selection to make sense.
Here's a better one (after googling "stephen forrest university michigan light source") :
[url]http://www.physorg.com/news64068597.html[/url]
From Nature magazine:[quote][b]Editor's Summary[/b]
13 April 2006
[b]The white light of technology[/b]
With energy conservation high on the political agenda, the search for economical light sources is a hot topic. An advance reported this week could be an important step in the field. It introduces a new architecture for making organic light-emitting devices that produce white light suitable for solid-state lighting. What is new is the use of fluorescent and phosphorescent light-emitting dopants arranged to optimize harvesting of the electric charge and achieve potentially 100% internal quantum efficiency. Technology of this type has the potential to make OLEDs (organic light emitting devices) much more efficient than incandescent lighting. Even at an early stage of development this new source is up to 75% more efficient than today's incandescent sources at similar brightnesses.[/quote]
I give you a [url=http://www.nature.com/nature/journal/v440/n7086/full/nature04645.html] link to the full text article at Nature[/url], but knowing that access to full text is not allowed for everyone, I'll copy the abstract (read "-1", etc. as "to the minus..."):
[quote]Nature 440, 908-912 (13 April 2006)
Received 19 June 2005; ; Accepted 13 February 2006
[b]Management of singlet and triplet excitons for efficient white organic light-emitting devices[/b]
Yiru Sun, Noel C. Giebink, Hiroshi Kanno, Biwu Ma, Mark E. Thompson and Stephen R. Forrest
Abstract
Lighting accounts for approximately 22 per cent of the electricity consumed in buildings in the United States, with 40 per cent of that amount consumed by inefficient (approx15 lm W-1) incandescent lamps. This has generated increased interest in the use of white electroluminescent organic light-emitting devices, owing to their potential for significantly improved efficiency over incandescent sources combined with low-cost, high-throughput manufacturability. The most impressive characteristics of such devices reported to date have been achieved in all-phosphor-doped devices, which have the potential for 100 per cent internal quantum efficiency: the phosphorescent molecules harness the triplet excitons that constitute three-quarters of the bound electron–hole pairs that form during charge injection, and which (unlike the remaining singlet excitons) would otherwise recombine non-radiatively. Here we introduce a different device concept that exploits a blue fluorescent molecule in exchange for a phosphorescent dopant, in combination with green and red phosphor dopants, to yield high power efficiency and stable colour balance, while maintaining the potential for unity internal quantum efficiency. Two distinct modes of energy transfer within this device serve to channel nearly all of the triplet energy to the phosphorescent dopants, retaining the singlet energy exclusively on the blue fluorescent dopant. Additionally, eliminating the exchange energy loss to the blue fluorophore allows for roughly 20 per cent increased power efficiency compared to a fully phosphorescent device. Our device challenges incandescent sources by exhibiting total external quantum and power efficiencies that peak at 18.7 plusminus 0.5 per cent and 37.6 plusminus 0.6 lm W-1, respectively, decreasing to 18.4 plusminus 0.5 per cent and 23.8 plusminus 0.5 lm W-1 at a high luminance of 500 cd m-2.[/quote]
No time to read and comment much on this right now, sorry
But it is an interesting development for OLED, job allowing I'll read it and comment later.
Note that [i]100% internal quantum efficiency[/i] does not mean 100% overall efficiency, I think it only means that all excited states do decay by light emission instead of by competing processes.
Jake