I was wondering if there's something similar to Moore's law (the power, or actually the number of transistors, of a cpu doubles every two years) on flashlights. So, does the efficiency / the maximum output of a single LED double every n years? Or is the growth of output linear or what?
"Moore's law" on flashlights?
- Thread starter D6859
- Start date
Help Support Candle Power Flashlight Forum
Well, performance has been climbing, that's for sure.
Just like moores for cpu, the real advances seem to be based upon individual breakthroughs that allow other breakthroughs. I don't think we're doubling every two years in efficiency, because we're over 50%, so I think efficiency gains must be incremental due to the math. As far as output, we did go from 100 lumens as high to over 2,000 lumens for one LED in maybe 5 years or so...and as LED are now part of mainstream residential lighting (Replacing the banned incans, etc...), further improvements are logically projected.
I think the difference is that the cpu are just adding transistors, or the moral equivalent in processing power...and the LED are primarily improving the ability to convert power into light, and increasing the amount of power that can be used for input, for its gains.
- Joined
- May 4, 2014
- Messages
- 650
Right now it seems that the battery technology is the key factor in this. Today we can't store enough energy in small cells for it to be viable with the more power-consuming drivers and LEDs. If we can get supercapacitors going we should be able to increase both runtimes and reliability tenfold without increasing the price too.
Oops, I had already forgotten I started this thread 
Thank you for your replies!
I read some article last week about breakthrough in battery chemistry. Little googling tells me that there have been more than one breakthroughs this year. I will be looking forward to getting my hands on those Li-ions with doubled capacity!
Thank you for your replies! I read some article last week about breakthrough in battery chemistry. Little googling tells me that there have been more than one breakthroughs this year. I will be looking forward to getting my hands on those Li-ions with doubled capacity!
InspectHerGadget
Enlightened
- Joined
- Apr 17, 2014
- Messages
- 247
It is heatsink capacity too. All those lumens even efficiently produced cause heat to build up in the light. It takes quite a big heat sink to put out 2000 Lumens say without the light getting too hot to hold in just a matter of minutes.
Even in fifty years time, a really powerful light will need a big heat sink and hence will be a big light, no matter what it is powered by.
Look at the SC600. It is rated to 1100Lumens almost but it's sustained output is half of that and it gets too hot for comfortable holding for most people.
The more things change, the more some things stay the same. Physics rules.
Even in fifty years time, a really powerful light will need a big heat sink and hence will be a big light, no matter what it is powered by.
Look at the SC600. It is rated to 1100Lumens almost but it's sustained output is half of that and it gets too hot for comfortable holding for most people.
The more things change, the more some things stay the same. Physics rules.
AnAppleSnail
Flashlight Enthusiast
Right now a 1000-lumen OTF light at about 100 lumens per watt (LED) will consume about 15W of electricity and emit about 3W of that power as photons. 12W of heating will result, leading to required stepdowns.
In three years, suppose Cree gets to 200 lumens per watt (LED). The same output will consume about 7.5W of electricity and emit about 3W of that power as photons. 4.5W of heating will result, meaning stepdowns would only be needed in hot areas. This is almost a 60% reduction in heat transfer required. Exciting, right?
RetroTechie
Flashlight Enthusiast
To continue that line of thought: such improved LED efficiency also means that a same output light can do with a smaller battery, have longer runtime, or higher output with the same battery. Everything better yet if battery tech improves as well.
How far the tech could go, depends on how far away it currently is from theoretical limits. For transistors, those limits consists of how small structures can work as a transistor. With limits being in the order of structures a few / a few dozen atoms long or wide. That's still a number of steps away from the 45 nm. or so that current CPU's use, and a loooong way from where semiconductors were 20 years ago. Hence Moore's law etc.
For LEDs, current tech is already significantly on the way to what's theoretically possible. So beyond today's 150 or 200 (?) lm/W for white LEDs there can be some more improvement, but for example a x10 gain in output won't happen anymore, ever. Period. Heat losses could be reduced, but (since light = energy, which can't be created from nothing) at some point there's no getting around that more light output requires more energy input.
I think biggest room for improvement is in battery tech. Energy density, safety, durability etc. are all things that potentially could be improved orders of magnitude.
How far the tech could go, depends on how far away it currently is from theoretical limits. For transistors, those limits consists of how small structures can work as a transistor. With limits being in the order of structures a few / a few dozen atoms long or wide. That's still a number of steps away from the 45 nm. or so that current CPU's use, and a loooong way from where semiconductors were 20 years ago. Hence Moore's law etc.
For LEDs, current tech is already significantly on the way to what's theoretically possible. So beyond today's 150 or 200 (?) lm/W for white LEDs there can be some more improvement, but for example a x10 gain in output won't happen anymore, ever. Period. Heat losses could be reduced, but (since light = energy, which can't be created from nothing) at some point there's no getting around that more light output requires more energy input.
I think biggest room for improvement is in battery tech. Energy density, safety, durability etc. are all things that potentially could be improved orders of magnitude.
InspectHerGadget
Enlightened
- Joined
- Apr 17, 2014
- Messages
- 247
It is hard to say I guess how much further they will improve. The laboratory efficiencies of 230 lu/W don't get achieved in practice due the the high currents driven through them. I read that 400 lu/W is the theoretical maximum but not sure how they calculate it.
Sometimes technology simply plateaus. There is simply no way of knowing what may or may not be developed.
RetroTechie
Flashlight Enthusiast
Hey, I just found this: Haitz's law.
Note this doesn't invalidate those theoretical lm/W limits (see bottom of that page), but is about cost/lumen and output per LED. Which makes sense, as there's no fundamental reason why one couldn't keep increasing LED output as long as losses keep getting lower & cooling methods keep up.
In other words: if above 'law' holds, expect 10W, 100W or even 1kW power LEDs at similar size/cost as today's 1W LEDs... That should be nice to know for throwy light builders among here...
Note this doesn't invalidate those theoretical lm/W limits (see bottom of that page), but is about cost/lumen and output per LED. Which makes sense, as there's no fundamental reason why one couldn't keep increasing LED output as long as losses keep getting lower & cooling methods keep up.
In other words: if above 'law' holds, expect 10W, 100W or even 1kW power LEDs at similar size/cost as today's 1W LEDs...
That should be nice to know for throwy light builders among here...
So maybe the answer is the next technology beyond LEDs? Understand, I have no idea what, if anything that might be, but if a completely different technology could be developed it could replace LEDs like LEDs replaced incandescents, yielding exponential gains in output and/or power efficiency.
Ken
Hey, I just found this: Haitz's law.
Note this doesn't invalidate those theoretical lm/W limits (see bottom of that page), but is about cost/lumen and output per LED. Which makes sense, as there's no fundamental reason why one couldn't keep increasing LED output as long as losses keep getting lower & cooling methods keep up.
In other words: if above 'law' holds, expect 10W, 100W or even 1kW power LEDs at similar size/cost as today's 1W LEDs...
Interesting!
But it says "In March 2014, Cree announced another prototype with a record breaking 303 lm/W efficacy @ 350mA." and "The theoretical maximum for a white LED with phosphorescence mixing is 250 lm/W." So those LEDs Cree has tested are not what we consider white?Thank you. I hadn't done my research very well when posting.
Phosphorescence mixing is not the same as blending LED frequencies. There are losses in phosphor conversion.
So, yes, the Cree sample is not white produced by that method and is probably in fact monochromatic at the optimal frequency where the product of watt efficiency and eye sensitivity is a maximum.
So, yes, the Cree sample is not white produced by that method and is probably in fact monochromatic at the optimal frequency where the product of watt efficiency and eye sensitivity is a maximum.
InspectHerGadget
Enlightened
- Joined
- Apr 17, 2014
- Messages
- 247
Hey, I just found this: Haitz's law.
Note this doesn't invalidate those theoretical lm/W limits (see bottom of that page), but is about cost/lumen and output per LED. Which makes sense, as there's no fundamental reason why one couldn't keep increasing LED output as long as losses keep getting lower & cooling methods keep up.
In other words: if above 'law' holds, expect 10W, 100W or even 1kW power LEDs at similar size/cost as today's 1W LEDs...
No you won't get say a 1000 Lumen emitter in 20 years time that will only draw the same current as 100 Lumen one would today. My reading is we're a substantial way towards the theoretical efficiencies achievable already. I don't think there will be any future revolution in lights, this is about it although there will obviously be some improvement but looking at maybe doubling efficiency over time, possibly quite a long time...or maybe not. It is the efficiency in practice that counts and that will always be at elevated temperatures.
As another poster said too, you have to double efficiency for light over the visible spectrum otherwise, it is just wasted energy if the eye can't see it ie. ultraviolet or infrared.
