How far have LEDs gone, in a broad sense?

Long time lurker here :wave: with a question about LED efficiency in the recent years past and to come.

I remember joining CPF a few weeks after Arc announced its retirement. Good god were people upset, and it rendered every Arc worth its weight in gold for a few years. Then the Nuwaii Q III stole our hearts with excellent quality for the cost, sporting the latest Luxeon III emitter that cranked out a whopping 20 lumens or so per watt. To me this was the first production light that set off the LED arms race we continue to see go on today.

Sorry for the trip down memory lane but it is part of the timeline I picture when it comes to LEDs. So today we are at hundreds of lumens per watt and I am just wondering when LEDs are going to be 100% efficient and available commercially? I think I read about them being 100% efficient in the lab and only so at tiny amounts of light for now. What possible uses would 100% efficiency entail? I dont know enough to make an educated guess but I feel like progress in LED efficiency came to a halt in the past few years due to a slow down of progression of computer/semiconductor technology (again a personal guess, I dont know jack about computers and its respective developments)

Well depends on what you mean by 100% efficiency. From my perspective I don't think that's exactly possible. But I wouldn't be too shocked if they come up with one since we are literally at the brink of greatness as in the fact that we extremely close to having all those crazy technologies we imagined taking off. The byproduct of an LED is heat and light. 100% efficiency would mean no heat just light. Although that will take away a few positive effects such as led lights keeping lenses fog free etc I'm sure that will be great. The hotter an LED becomes, the less lumens per watt it can produce. This means that if there is no driver regulating the power, the LED will continue to suck more power till it burns out. Or if there is a driver limiting its power, it'll simply start to dim over time. Heat has been literally 50% of the battle when it comes to LED light output. None the less we currently have 25,000 lumen lights for sale for civilian use for prices lower than what a 1000 lumen light cost a half dozen yrs ago. If heat isn't an issue, assuming we can get the power needs down we can see light much much brighter! Brighter future eh?

I think they are around 30% efficient. They have been increasing efficiency at about 7% a year.

There is new incandescent technology that shows promise to be far more efficient than current LED's, but by the time that's anywhere close to market we could see a huge jump in LED tech far greater than the steady minor increases we've been use to.

Just like anything else in this world, they probably already have the ability, but from a business perspective; they need to make incrimental advancements.

They can't just jump all in, otherwise there is limited room for advancement and they will put themselves out of business. Consumers need to see change even if it's minor, otherwise they start crying

INFRNL said:

Just like anything else in this world, they probably already have the ability, but from a business perspective; they need to make incrimental advancements.

They can't just jump all in, otherwise there is limited room for advancement and they will put themselves out of business. Consumers need to see change even if it's minor, otherwise they start crying

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I don't know about that, or if they do have larger advancements they are not economical enough, yet. If the tech was available you would have competitors upping one another to gain more market share.

So there has been no noticable slowdown in efficiency progress? I only ask because I feel like 1x18650 lights have been stuck at around a 1000 lumens for the past fewyears. Im not saying that 1x18650s arent brighter than 1k lumens, but that their average advertised lumens hasnt risen as much in the past 3 years as they did 3 years prior. Again this is a personal deduction, I know that advertised lumens can be misleading for the question Im asking, since overdriven turbo modes are often loudly touted by companies.

Mags said:

So there has been no noticable slowdown in efficiency progress? I only ask because I feel like 1x18650 lights have been stuck at around a 1000 lumens for the past fewyears. Im not saying that 1x18650s arent brighter than 1k lumens, but that their average advertised lumens hasnt risen as much in the past 3 years as they did 3 years prior. Again this is a personal deduction, I know that advertised lumens can be misleading for the question Im asking, since overdriven turbo modes are often loudly touted by companies.

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I"m guessing that the 1000 lumen rating is probably some exaggerating there with 700-900 lumen lights getting that rating and that 1100 and 1200 lumens doesn't "pop" out at people at much as 1000. LEDs are getting more efficient but the noticeable light output doesn't scale the same rate it takes a multiple of lumens output to discern a difference and going from 500 to 1000 may not be as noticeable as going from 50-500 even though the jump in lumens is less.
In other words to be noticeably brighter the 1000 lumens may need to be pushed perhaps to 2500 lumens which has several obstacles in that unless you have a lot of LEDs in an array to produce this much light you take a hit on efficiency perhaps several hits as you have to deal with a lot more heat and higher current drivers and more optics and reflectors and emitters the cost per lumen skyrockets to get there.

LEDs are commercially viable now although I'm not entirely sure of their "longevity" as many commercial LEDs consist of a bunch of lower output smd emitters which aren't as efficient on average as the top end cree X2 series with 80-120 lumens/watt instead of 150-200 lumens/watt.

If you go to the store and try to buy LED screw in bulbs you will find that the 40 and 60 and often even 75 watt bulbs are close to the same lumens/dollar while the 100 watt takes a big jump in price. When you try and hit a certain amount of lumens per area of available heatsink the cost starts to escalate.

Even though LEDs have been advancing steadily in efficiency the focus has also been in handling heat better so you can drive single emitters to an increasingly higher output compared to efficiency gains.

Current LEDs are in the 200-220 lumens/watt range I believe, increasing that to 250 lumens/watt won't be as noticeable in order for it to be noticeable we would need higher output efficiency that is for LEDs to give 200 lumens/watt at inputs of 3 watts instead of 1 watt tapering downwards from there. If you could get 1000 lumens from an emitter at 200 lumens/watt efficiency it would be impressive. I'm not sure what the drop in efficiency is at that range though... perhaps a loss of 25-40% in efficiency which translages to 250-400 lumens lost in output for the same power input.

Like Lynx said, I think most of the first 1000 lumen lights were 900 or less. Then they became real 1000 lumen lights, and now they are reaching 1200 lumens with similar LED's. However, with a single 18650 you can hit upwards of 1900 lumens with some of the newer, larger LED's or triples.

IMHO the "comfort zone" for 1X18650 lights, given current technology, should be around 1000 lumens. Lights light Nitecore's TM03, Concept 1, Zebralight's SC600F/Fd Plus are pushing the boundary but they simply don't have the mass to dissipate the heat, nor do current 18650s store enough energy for these lights to have practical runtimes on turbo.

lm/w wise, The good old XM-L2 delivers 170lm/w whereas its new brother, the XP-L2, does 169lm/w. However the XP-L2 offers other benefits like increased maximum output, lower forward voltage and so on.

Recently Cree announced the NX technology LED which claims to have 4X the lumen density of a Xlamp (XM-L2, XP-L2, XHP50 etc.) LED. Imagine a M43 with 12 of these.

TCY said:

Recently Cree announced the NX technology LED which claims to have 4X the lumen density of a Xlamp (XM-L2, XP-L2, XHP50 etc.) LED. Imagine a M43 with 12 of these.

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Imagine 4x the heat to get rid of without a larger light to help with the mass.

Lynx_Arc said:

Imagine 4x the heat to get rid of without a larger light to help with the mass.

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Doesn't matter, there's bound to be manufacturers throwing themselves into the lumen war, claiming that their 1X18650 lights can pump out 4000 lumens but doesn't tell you the 4000 lumen mode steps down to 800 in 5 seconds:thumbsup:

TCY said:

Doesn't matter, there's bound to be manufacturers throwing themselves into the lumen war, claiming that their 1X18650 lights can pump out 4000 lumens but doesn't tell you the 4000 lumen mode steps down to 800 in 5 seconds:thumbsup:

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This is why I find it hard to gauge LED progress unless Im looking at spreadsheets of emitters. Most lumen ratings from manufacturers are an impractical turbo mode that steps down at some point

TCY said:

Doesn't matter, there's bound to be manufacturers throwing themselves into the lumen war, claiming that their 1X18650 lights can pump out 4000 lumens but doesn't tell you the 4000 lumen mode steps down to 800 in 5 seconds:thumbsup:

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I'm sure they will have them on Ebay about -2 years ago

INFRNL said:

Just like anything else in this world, they probably already have the ability, but from a business perspective; they need to make incrimental advancements.

They can't just jump all in, otherwise there is limited room for advancement and they will put themselves out of business. Consumers need to see change even if it's minor, otherwise they start crying

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Just like what else?

The counterargument is that anybody with a standout technology they're sitting on has an opportunity to bring it to market, dominate the market, and then if the market becomes saturated, invest all the huge profits they made in some other venture, ending up wealthier both in the short term and the long term.

Realistically though, putting your best product on the market when it's ready instead of waiting tends not to put people out of business. Some people suppose that because LED's last so long, at some point everybody will have all the LED's they need and the market will be dead. That doesn't happen in other markets with long-lasting products, though. Think about table flatware (eg, forks and spoons) for example. That's a product with almost nothing to fail which genuinely does last decades with ease, and nobody is clamoring to replace "obsolete" forks, yet it's still an active market in its own right.

LED's may at some point reach their peak market penetration and the market will shrink, but it won't go away, and the general business imperative is to make as much money as you can before that happens.

eraursls1984 said:

I think they are around 30% efficient. They have been increasing efficiency at about 7% a year.

There is new incandescent technology that shows promise to be far more efficient than current LED's, but by the time that's anywhere close to market we could see a huge jump in LED tech far greater than the steady minor increases we've been use to.

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Efficiency isn't a commonly used figure with light sources because the human eye response varies with wavelength. Therefore, a 100% efficient red light does not produce the same lumens as a 100% efficient green light. That's part of why we usually talk about efficacy (lumens/Watt) instead of efficiency.

That said, a high CRI light source that was as efficient as it theoretically can be produces about 300 lumens per Watt, and a more typical CRI light might be 350-400 lumens per Watt.

The best LED's are currently achieving around 200 lumens per Watt (not counting power supply efficiency) at moderate CRI, so we're maybe half way to the theoretical best performance possible.

Wikipedia has a discussion of this and some example figures:
https://en.wikipedia.org/wiki/Luminous_efficacy#Luminous_efficacy_of_radiation

Be aware that the efficiency values in the table there are not thermodynamic efficiency (getting as many photons as possible per Watt), which would be how in engineering we'd normally talk about efficiency, but luminous efficiency, which is a comparison against the efficacy of 555nm green light.

The report I saw on the new incandescent technology came from the researchers working on them, and it suggested it might achieve parity with LED efficacy, not beat it.

eraursls1984 said:

I think they are around 30% efficient. They have been increasing efficiency at about 7% a year.

There is new incandescent technology that shows promise to be far more efficient than current LED's, but by the time that's anywhere close to market we could see a huge jump in LED tech far greater than the steady minor increases we've been use to.

Click to expand...

The ceiling is the roof.
-Michael Jordan

Just like anything else in this world, they probably already have the ability, but from a business perspective; they need to make incrimental advancements.

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Just like what else?

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Racquetball racquets.