# LED technology, how far can/will it go?



## brembo (Jun 23, 2011)

I am very new to this game, the game being "light tools". I am astounded by the current crop of emitters/light engines that are available for pocket change. Now one can snag a CUSTOM host with a spec'd emitter for ~150 bucks that absolutely stomps a mid 1990s top-of-the-line light that would have cost ~200$ 1990 dollars. WOW. It's a quiet revolution that I think is sliding by the general public. Yeah, we see HIDs in some cars, and a few automakers are tinkering with LED main lights, but overall LED tech is kinda "meh....yeah they are okay". I'm pretty stoked at the idea that my wee little S-Mini can punch out 300+ lumens for over two hours and still nestle in my pocket comfortably, and it's not as efficient as many other models/brands. This is some seriously cool technology.

Computers have followed Moore's law closely, doubling computer power every two years or so. Can we expect to see the output of LEDs to follow a similar path, or is making photons bounce around more of a zero sum game? In twenty years will someone be changing my diaper with a 10k lumen light that runs off static electricity generated by simply walking around, or is there a threshold for light vs. energy?


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## yliu (Jun 24, 2011)

Interesting question. I am no expert in this field, but I still have to comment on this!

I guess the limit of lighting technology would be when an emitter can transfer the energy into light with no loss or heat etc.


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## EZO (Jun 24, 2011)

I don't know the ultimate answer to your question about what lighting technology will be in use at your retirement facility but LEDs are already an example of an aspect of Moore's Law and have been since they became a practical electronic component in the early 1960s. Although Moore's Law originally described the doubling approximately every 18 to 24 months of the number of transistors that can be placed inexpensively on an integrated circuit it has taken on a broader meaning and is now linked to other types of digital electronic devices in regard to memory capacity, processing speed and even the number and size of pixels on digital camera sensors. As semiconductors, LEDs have been on the same path. In the beginning they were available only in red and were only bright enough to be used as replacements for incandescent and neon display indicator lamps and they were extremely expensive. A short time later, they were introduced in seven segment displays (digital clock and calculator numerals). Eventually, as LED materials technology advanced their efficiencies and brightness increased, and other colors were developed which ultimately led to the high brightness LED's used in today's flashlights. Of course, these advances were a result of processing optimization that also dramatically lowered prices per unit.

Actually, LEDs have their own counterpart to Moore's Law known as *Haitz's Law* which states that every decade, the cost per lumen (unit of useful light emitted) falls by a factor of 10, and the amount of light generated per LED package increases by a factor of 20, for a given wavelength (color) of light.

Both Moore's Law and Haitz's Law describe trends and as such they are thought to have finite limits. 

How fast and far LED's will go remains to be seen but continuing the trend, LEDs are expected to become the most efficient light source within the next 10 years.

P.S. This thread seems to be in the wrong forum and probably should be moved over to the LED forum.


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## 2filthy3 (Jun 24, 2011)

Well if an ideal black body emitter in the 'white' light spectrum is 250lm/w, then aren't we almost half way there already?


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## beamis (Jun 24, 2011)

No. A black body emits all kinds of radiation all over the spectrum. That takes a lot of energy that doesn't contribute much to lumen count. LEDs have a more limited distribution of energy. If my recollection is correct, at a 555 nm wavelength, 100% efficiency is somewhere around 680 lumens per watt. Of course, having white light means more than just pure green light and so the level would be lower.


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## jhc37013 (Jun 24, 2011)

I'm not sure about the future total output of light's but I think we will see the biggest leaps in battery's and hopefully efficiency. Right now I can carry around a pocket light that outputs 500lms for 2hrs, hopefully in the future I will carry around 650lmns for 6hrs in that same sized light. 

With the release of the XM-L almost any light that uses it is plenty bright for me and in some cases much more brighter than I had anticipated in just a few years so now I find myself looking more at runtime and regulation, battery technology is where we need to look.


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## Norm (Jun 24, 2011)

Moved to General Flashlight Discussion.
Norm


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## beerwax (Jun 24, 2011)

.............


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## 2filthy3 (Jun 24, 2011)

This is why I specified only in the spectrum of 'white' light, say 4300-6000k, which I thought was 250lm/W, though this could definitely be incorrect.


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## mvyrmnd (Jun 24, 2011)

I think the real future for LED efficiency is when we can produce white light without the need for phosphor. That's where we lose a lot of efficiency right now.

Not long ago we thought blue LED's were impossible. Once we can shed the need for phosphor to create white light, we can have wider spectrum emitters and far less light lost to heat and lost in the down-converting of blue light to yellow.


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## Arcus Diabolus (Jun 24, 2011)

So, to sum it all up, we can say that in the future we can count and focus on improving battery efficiency and finding a way to produce LEDs that produce the whole light spectrum. Correct?

Personally, I too want to focus on the production of LEDs that can emit the whole spectrum.


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## Outdoorsman5 (Jun 24, 2011)

Maybe LED technology will be replaced by something better. I just saw this link on this thread posted by "parnass". This video clip, entitled _Flashlight Experiment LEP vs LED_, implies that plasma technology could replace LEDs.

Interesting.


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## Napalm (Jun 24, 2011)

Arcus Diabolus said:


> Personally, I too want to focus on the production of LEDs that can emit the whole spectrum.


 
X-Ray too? You're either a perv or you work for TSA :devil:


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## EZO (Jun 24, 2011)

beerwax said:


> i believe that there is also another law, that needs a good name, that says that for every increase in led lumen output there is an at least parallel increase in the minimum acceptable EDC brightness level. or to put it another way we used to carry 30 lumens, now we need 500 lumens in the pocket.


 
There actually is a law that one could apply here to some degree even though you mention this in a tongue & cheek comment about EDC cravings. It was proposed by Ray Kurzweil, and is known as *The Law of Accelerating Returns* which states that "history of technology shows that technological change is exponential" and argued for extending Moore's Law to describe exponential growth of diverse forms of technological progress. 

Well, of course we all want the newest, latest, bestest!  The only problem with rapidly accelerating technology is the ability to keep up buying it. :sigh: As consumers we crave the rewards of these rapidly accelerating trends of technology. (Sounds like there's really another law in there somewhere, but beerwax will have to propose the name.)


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## EZO (Jun 24, 2011)

Norm said:


> Moved to General Flashlight Discussion.
> Norm



Norm, I hope you don't mind my comment here, but considering the OP's specific reference to the future of LED technology in regard to Moore's Law and the title of the thread, _"LED technology, how far can/will it go?"_, are you sure this thread belongs in the General Flashlight Discussion and not the LED Forum?

Eh, perhaps it doesn't really matter but I decided I would ask.

Respectfully,
EZO


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## menoceros (Jun 24, 2011)

trying to stay with the thread, but bringing in other facets. My city changed to LED traffic lights over ten years ago for an appreciable savings in time, labor and materials over constantly changing incan. light bulbs. The government is already realized that CFLs are not the solution to home lighting due to disposal problems etc, and are now pushing led replacement "bulbs" for home lamps. Right now they are relatively expensive, even taking the longevity into consideration. They are being used for tail lights on cars, tail and running lights on trailers such as semis and boat and travel trailers. I feel we will see more and more penetration into daily life, not just in our EDCs and other work lights.


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## Mdinana (Jun 24, 2011)

menoceros said:


> trying to stay with the thread, but bringing in other facets. My city changed to LED traffic lights over ten years ago for an appreciable savings in time, labor and materials over constantly changing incan. light bulbs. The government is already realized that CFLs are not the solution to home lighting due to disposal problems etc, and are now pushing led replacement "bulbs" for home lamps. Right now they are relatively expensive, even taking the longevity into consideration. They are being used for tail lights on cars, tail and running lights on trailers such as semis and boat and travel trailers. I feel we will see more and more penetration into daily life, not just in our EDCs and other work lights.


 They're also being used more and more as headlights and aux. lights on military vehicles. Some of the lights are the Vision-X type of circular lights with approx 10 LED's. Others are 2 or 3 LEDs with a massive optic in front of them. They appear to light well out to about 50 yards (though with the glare, you're covering your eyes at 200 yards). I assume it'll be a matter of a few years before civilian headlights start drifting that way, as we're already seeing some aux lights being offered for off-roading.


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## gcbryan (Jun 25, 2011)

I think I read somewhere a few years ago that battery technology was the limiting factor in electronics and anything else that requires batteries. I don't remember the details (unfortunately) and I knew very little about batteries really but there were certain limiting factors in battery technology that would not lead us to expect large increases as we have with other technology.

Maybe it just had to do with physics and there being no free lunch but my take on the article was that improvements in battery technology would be very small and incremental.


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## Lynx_Arc (Jun 25, 2011)

gcbryan said:


> I think I read somewhere a few years ago that battery technology was the limiting factor in electronics and anything else that requires batteries. I don't remember the details (unfortunately) and I knew very little about batteries really but there were certain limiting factors in battery technology that would not lead us to expect large increases as we have with other technology.
> 
> Maybe it just had to do with physics and there being no free lunch but my take on the article was that improvements in battery technology would be very small and incremental.


 
Battery tech is one limiting factor. Alkalines and nimh are not really improving in long term usable capacity and lithium based battery improvements are rather small and slow coming I figure a new chemistry could help things or new battery technology perhaps. I to know that electronics that require memory and microcircuitry are improving by shrinking the die size the power consumption keeps going down to such levels that things like a 1 AAA radio that runs for 30 hours is possible when most radios used to take 4D cells years back.


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## EZO (Jun 25, 2011)

Posters to this thread have touched on various ancillary topics like flashlights, batteries, and other related issues but in keeping with the OPs actual title, "LED technology, how far can/will it go?", the question primarily seems to be, how bright will LEDs eventually get and at what efficiency? Indeed, there are other factors such as R&D budgets, marketplace requirements and demands, costs, power supply issues, and others.

For anyone who feels like taking the time to read an interesting and informative 13 page paper from 2010 by two industry professionals on this very topic titled, *"Solid-state lighting: ‘The case’ 10 years after and future prospects", *(27 SEP 2010) - you can find it in PDF format HERE or HTML format HERE.*

*It makes for some very interesting reading as both authors don't entirely agree but they do feel that the demands of the marketplace will ultimately determine "how far will it go" and they provide a lot of fascinating and detailed background, history, facts, theory and opinion.*

In fact, they conclude their paper with a remarkable last paragraph that predicts the end of the revolution in electric lighting that began 130 years ago with the introduction of the Edison bulb as SSL (Solid State Lighting) achieves the required efficiencies; which isn't too far off!

*_"Since Edison's first installation of electric lights over 130 years ago, the industry developed half a dozen new electricity-based lighting technologies, each improving efficacy, cost, or quality of light. Over the next decade SSL will approach the end of the efficacy ladder and meet or exceed the market's needs with respect to cost and quality. There will be little room left to justify the substantial investments needed to develop an alternative newer technology. The series of revolutions in lighting covering the entire history of mankind from campfire to candles to light bulbs to SSL will come to an end. The revolutions in lighting will be over!"_

Certainly LED lighting will be with us for a long time to come, but personally, I find it hard to fully accept the above statement, if only because of the number of times down through history when such broad and finite predictions have been proven wrong. Technology has a unique way of surprising us. How many have unexpectedly ended up in the dust bin? I am sure that those who made the transition from burning candles to whale lamps and then to gas lamps couldn't foresee the eventual paradigm shifting invention of the lightbulb and the development of electrical power and those that adopted the lightbulb didn't foresee Solid State Lighting. As one example OLED (granted, another form of SSL but not mentioned in the article) is in its very earliest stages of development and many years from now OLED or perhaps another technology may supplant LEDs for reasons other than or in addition to efficiency or cost. OLED, like LEDs were initially developed with other uses in mind than as general lighting devices so the idea that R&D will not be focused on lighting could be off the mark. Our lives are filled with so many accidental or unintended inventions and technological breakthroughs they are hard to count. I have a hunch that the field of nanotechnology will yield some astonishing advances in materials science that we cannot even begin to imagine today and that lighting technology will be one of the places it will leave its mark. Just my opinion. Anyway, I'm still digesting the lengthy and interesting article and it is definitely worth taking the time to read it.


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## Chevy-SS (Jun 26, 2011)

EZO said:


> _......."__The series of revolutions in lighting covering the entire history of mankind from campfire to candles to light bulbs to SSL will come to an end. The revolutions in lighting will be over!"_............



Wow, that statement seems incredibly short-sighted. We really have no idea what the next 'revolution in lighting' might even consist of. We may be powering lights of the future from dark matter or gravity or some other quantum force.


It was very interesting to learn about "Haitz's Law". I had no idea that existed.

-


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## beerwax (Jun 26, 2011)

..........


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## mvyrmnd (Jun 26, 2011)

beerwax said:


> a gorgeous flat panel light with adjustable spectrum or wallpaper that can be activated to glow might be successful. maybe not in a torch.


 

Now you're onto something! Just like I have a 1m^2 skylight in my ceiling which looks perfectly normal, I'd love a 1m^2 OLED panel that I could adjust the colour to suit my needs, that could output maybe 2500-3000 lumens on full belt for when I'm cooking and want really bright light, and infinitely dimmable so I can have mood lighting 

Now, someone go and make it!


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## EZO (Jun 26, 2011)

mvyrmnd said:


> Now you're onto something! Just like I have a 1m^2 skylight in my ceiling which looks perfectly normal, I'd love a 1m^2 OLED panel that I could adjust the colour to suit my needs, that could output maybe 2500-3000 lumens on full belt for when I'm cooking and want really bright light, and infinitely dimmable so I can have mood lighting
> 
> Now, someone go and make it!



It's coming. It's coming! 

http://www.crunchgear.com/2010/01/13/color-temperature-adustable-oled-lighting-yes-please/

http://www.cens.com/cens/html/en/news/news_inner_30761.html


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## 2xTrinity (Jun 27, 2011)

2filthy3 said:


> Well if an ideal black body emitter in the 'white' light spectrum is 250lm/w, then aren't we almost half way there already?


 
The most efficient "blackbody" radiator (at about 95 lumens/watt) is the sun at 5700K. This is because the human eye's sensitivity peak coincides with the peak wavelength emitted by the sun. Any hotter, more UV light is emitted. Any cooler, more IR is emitted (eg incandescent, limited by the 3700K melting point of tungsten). 

250 lm/w is plausible if you were to have a blackbody spectrum with all wavelengths shorter than ~450 and longer than ~630nm excluded. This kind of hypothetical spectrum might be where you heard than number. 

As far as LEDs go, the best production blue LEDs already have nearly 80% wallplug efficiency. The vast majority of the loss is in LEDs on the market is in the phosphor layer, and most (but not all) of this is unavoidable even in theory. When blue light is converted to green and red light, the difference in energy levels between those photons is dissipated as heat. This is called stokes loss. Using a 100% efficient blue LED, and a phosphor that had stokes loss only (but not losses due to unwanted scattering and absorption), you might see >220lm/watt. 

LEDs using "perfect" red, green, and blue LEDs could likely achieve lm/watt in the 300s. There would then be a tradeoff between better color rendition/color accuracy, and efficiency -- it would be possible to choose "red" and "blue" wavelengths that are themselves pretty close to green, and have a greenish-white light with >400lm/watt. 

One way to increase lumens/emitter emitter is by using "remote phosphors" in things like household lamps -- with a spread out phoshpor, the waste heat (even today, this is mostly in the phoshor) would naturally be more spread out and easier to deal with. For indoor lighting it makes little sense to having a bright point source only to have to intentionally diffuse it anyway. I suspect the peak efficiency for the LEDs themselves (in lm/watt) won't improve much, the gains will be in being able to maintain high efficiency at higher current (less "droop"), and in bringing down the cost/lumen.


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## flashflood (Jun 27, 2011)

2xTrinity said:


> The most efficient "blackbody" radiator (at about 95 lumens/watt) is the sun at 5700K. This is because the human eye's sensitivity peak coincides with the peak wavelength emitted by the sun. Any hotter, more UV light is emitted. Any cooler, more IR is emitted (eg incandescent, limited by the 3700K melting point of tungsten).
> 
> 250 lm/w is plausible if you were to have a blackbody spectrum with all wavelengths shorter than ~450 and longer than ~630nm excluded. This kind of hypothetical spectrum might be where you heard than number.
> 
> ...


 
Very informative, interesting, and well explained. You should teach. :thumbsup:


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## 2filthy3 (Jun 29, 2011)

2xTrinity, thanks for the informative response.


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## RCantor (Jun 30, 2011)

EZO said:


> ... The series of revolutions in lighting covering the entire history of mankind from campfire to candles to light bulbs to SSL will come to an end. The revolutions in lighting will be over.



Yeah, right. Remember "64K ought to be enough for anyone"?


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## RCantor (Jun 30, 2011)

BTW, my cell phone has an active matrix OLED and it's gorgeous.


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## lightfooted (Jun 30, 2011)

Wow...some very interesting reading there....I do tend to believe that as to how far it can/will go is basically as far as we will *need* it to go. Think about it...I would guess that most of us have more computing power in our pockets than was available to Neil Armstrong when they touched down. I'd like to think that LEDs are the next generation of lighting but heck maybe something new will pop-up outta no where that's cheaper and better but maybe technology couldn't have produced just a few years ago. Maybe carbon nanotubes will pave the way to a micro carbon-arc lamp that can run off of a AA cell and produce 2000 lumens.

And just to add to the reading list...an interesting development in battery technology: http://techon.nikkeibp.co.jp/english/NEWS_EN/20110628/192954/


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## Cataract (Jun 30, 2011)

Interesting comments in here. 

I think that it is likely that LED technology will be replaced long before we reach the maximum output for a practical light source. Then again, the maximum output of that source will be relative to the application and what is judged as being too much. For interior lighting, for instance, more sources with less output would be better so as not to blind the occupants with glare and we are likely to go for less light output than we already have, as we can put light sources in more places. As for searchlights and projectors, the limit is likely when we see the beam more than the target, and I feel we're soon coming close to that with cool LED's, but with a broader spectrum, that limit could more than double. They might also come up with ingenious ways to illuminate the target only by blocking specific wavelengths or the likes.

Then you have the special applications... could an LED or it's replacement be strong enough to create a tool that uses light to cut metals, starts fires or even propel light crafts and replace the laser in those applications? The LED might see its successor come before we reach that point, but I believe that is all possible.


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## burpee (Jun 30, 2011)

One of the improvements to LED fabrication that could make a difference in flashlight efficiency would be producing "curved" wafer emitters.

Like the OLED fabrication - only different in the idea that these "curved emitters" would have only one set of poles - as a single LED. 

But follow along here- it would feasible _to nearly double the amount of light emitting material on a curved surface while not increasing the length nor width of the emitter._

Currently emitter material is a flat wafer, and because of this shape less light is distributed as the angle to the emitter changes.

My perspective suggests a curved emitter coupled to the appropriate reflector could change the shape of beams to come...... Ok, yuk yuk, or maybe not.......


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## shao.fu.tzer (Jun 30, 2011)

EZO's brought up many great points.. I've always correlated the power increase of LEDs to Moore's Law (I didn't know of Haitz's law or whatnot)... Even the manufacturing process shares many similarities to that of CPUs... Think of all the similarities between CPUs and LEDs... Though they come off the same assembly line, some are better than others... You can overclock a CPU just like you can overdrive an LED... some CPUs and LEDs handle it better than others - but cooling is paramount in either... I believe LEDs will continue to grow in power and efficiency for quite some time before possibly leveling off somewhere maybe 20-30 years down the line, in which time they'll be replaced with some new technology derived from jellyfish DNA.

Shao


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## LEDAdd1ct (Jul 1, 2011)

Shao, the non-disclosure agreement you signed forbids you from speaking about the jellyfish lighting until the official press release!


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## Lynx_Arc (Jul 1, 2011)

LEDAdd1ct said:


> Shao, the non-disclosure agreement you signed forbids you from speaking about the jellyfish lighting until the official press release!


 
that has something to do with squid pro quo eh?


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## Thomas Carey (Jul 1, 2011)

I believe that LED's are going to continue to replace other types of lighting as technology improves etc. I wonder how long it will be till we see them being used in headlights on cars rather than just in tail lights, and break lights.


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## wiley2 (Jul 1, 2011)

I have two LED's on my HTC sensation and they don't make that much of an effect when I try to use the flash.


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## EZO (Jul 1, 2011)

shao.fu.tzer said:


> I believe LEDs will continue to grow in power and efficiency for quite some time before possibly leveling off somewhere maybe 20-30 years down the line, in which time they'll be replaced with some new technology derived from jellyfish DNA.
> 
> 
> LEDAdd1ct said:
> ...



*It's too late!* There's already a book out about this and three scientists (Martin Chalfie, Roger Tsien and Osamu Shimomura) won a Nobel Prize researching the subject. For the time being it is being used primarily in biotechnology and medical research but according to the blurb for the book "Glowing Genes - A Revolution in Biotechnology: 

_"__"For most of us biotechnology is a great mystery, sometimes presented as a frightening use of science when, in fact, it will greatly improve the ability of the earth to feed us all and also help us live long, healthier lives. Glowing Genes: A Revolution in Biotechnology (Prometheus Books) by Dr. Marc Zimmer, Ph.D., may seem too exotic to even contemplate reading, but it will prove to be easily understood as it describes an amazing new area of biotechnology that will help fight cancer, create new products, improve agriculture, and even combat terrorism. *The subject of the book is a green fluorescent protein that has existed in one species of jellyfish that, in 1994, was cloned, giving rise to potentially revolutionary applications.* Imagine a glowing gene that lights up in the presence of anthrax spores and other chemical warfare agents? Imagine a gene that causes crops to glow, indicating they need more water? In the future, people who have long since been accustomed to their use will wonder how we ever lived without them."_​


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## Dude Dudeson (Jul 1, 2011)

burpee said:


> One of the improvements to LED fabrication that could make a difference in flashlight efficiency would be producing "curved" wafer emitters.
> 
> Like the OLED fabrication - only different in the idea that these "curved emitters" would have only one set of poles - as a single LED.
> 
> ...


 
This is a very interesting concept.


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## EZO (Jul 1, 2011)

Curved wafer emitters would be a really cool idea but I don't believe they could be manufactured that way. Even OLEDs are only "curved" because they are on a flexible substrate that is produced as a flat material. Assuming it could even be done I imagine that producing curved LED emitters would probably be an expensive process. Then again, curved emitters could have some interesting applications. For example, I imagine one could be mounted to mimic a filament in an A19 type bulb if it could emit light in a more omnidirectional pattern than a traditional surface mount component.

Question: burpee, are you suggesting a convex or a concave "curved" LED wafer?


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## Dude Dudeson (Jul 1, 2011)

I've had some more thoughts about the "domed wafer" concept. True, more surface area in the "same sized" deal, but we're already at a point where heat management is a huge limiting factor in terms of the size of the flashlight itself.

In other words - "packing more heat" (no pun intended) into the same sized flashlight doesn't seem to be a very logical pursuit at this point...

But I guess with BIG flashlights maybe this could be viable...


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