230% Efficient LEDs

pretmetled

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Please read my post which attempts to explain what is happening in a way people without expertise in quantum physics can understand.

If you mean the post right above in this thread, then yes I read it since it's right above in this thread.

Thermal energy can be converted to photons, as can lattice vibrations.

Which is what the hot metal stick example was exemplifying. ;)

...

edit: now why is this post suddenly listed at top of thread? o_O .... editing post to hopefully "fix" that.
 
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Mattaus

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***Apologies if this does not belong in this section of the forums, or if this is repeated news. I searched and could not find it posted previously.***

So some interesting news taken from Gizmodo but I saw it elsewhere yesterday:

Light bulbs have always required more electricity than they need to produce light because the energy conversion process — changing electricity to light — was inefficient. But an MIT research team has just shown that an LED can actually give off more light than it consumes in electricity.
Incandescent bulbs are the poster child of inefficient energy conversion. The devices heated a filament with an electrical current which not only produced light, but a lot of waste heat as well. Fluorescent bulbs, CFLs and even conventional LEDs all generate the same waste heat to varying (albeit much smaller) degrees but none has ever reached 100 per cent efficiency — a mark known as "unity efficiency".


The team from MIT posited that while the bulbs energy requirements decrease at an exponential rate (halving the voltage reduces the input power by a factor of four), the lumen output would decrease linearly (halve the voltage and the lumens drop by half as well). This means that at some point, the amount of lumens the bulb is emitting would be more than the amount of energy spent — essentially "free" light.


Granted, this point occurs only when using minuscule amounts of electricity to power incredibly dim bulbs. In their experiments, the team was able to generate 69 picowatts of light from just 30 picowatts of energy. They did so by harnessing waste heat, which is caused by vibrations in the bulb's atomic lattice, to compensate for the losses in electrical power. The device also reacts to ambient heat in the room to increase its efficiency and power the bulb.

This process cools the bulb slightly and could eventually be employed to manufacture "cold" bulbs that don't generate any heat, only light. And, since the same physical mechanism from these tiny bulbs can be applied to any LED, they likely will be. Original Source via Physics.

One day it will hopefully be a bit brighter :thumbsup:

- Matt
 

mvyrmnd

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So if we run 100 billion XP-G's at 30 picowatts a piece, we'd be getting 6.9W of light for 3W of electricity. I think. That many zeros messes with my brain.
 

Th232

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If the extra energy comes from the thermal energy in the bulb (waste or from its surroundings), I can see this going well in warm countries. People in colder climates will to turn up their heaters a bit more though...
 

Mattaus

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If the extra energy comes from the thermal energy in the bulb (waste or from its surroundings), I can see this going well in warm countries. People in colder climates will to turn up their heaters a bit more though...

So what you're saying is that we'll be right here in (mostly) sunny Australia. :nana:

It's a step in the right direction at least. The speed at which most things are advancing is insane these days, and just about the only thing that is not moving as fast as everything else is batteries. So we need to get more efficientl, though it wouldn't harm anyone if both improved hand in hand.
 

Th232

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It's a step in the right direction at least. The speed at which most things are advancing is insane these days, and just about the only thing that is not moving as fast as everything else is batteries. So we need to get more efficientl, though it wouldn't harm anyone if both improved hand in hand.

You just made me realise something. My titanium lights with their lower thermal conductivity will perform better than my Al lights, which will take away all that valuable heat from the LED and waste it heating the surrounding air. That would be really funny to see.
 

Mattaus

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You just made me realise something. My titanium lights with their lower thermal conductivity will perform better than my Al lights, which will take away all that valuable heat from the LED and waste it heating the surrounding air. That would be really funny to see.

Actually the heat sinking practices we currently all strive to implement would become null and void...flashlight design would/could change dramatically. I am of course only thinking about flashlight applications here. I'm sure there are many more far reaching implications.
 

StarHalo

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69 picowatts isn't enough for any sort of lighting application..

But if you can indeed see very few or individual photons in total darkness, as has been posited here, then a bunch of these micro-output micro-LEDs could work in night vision display of some sort..
 

AnAppleSnail

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69 picowatts isn't enough for any sort of lighting application...
I dunno, you'd only need about 21 million of these to produce almost a whole lumen in green light.

uYX5f.png


 

TEEJ

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There ARE some members here who would BUY a light that put out a 1/21,000,000 lumen "Firefly" mode.

:D

And there would be some others who would complain THAT'S too bright.

:D
 

TEEJ

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Your average low-res camera display has about 200,000 pixels in it; that would be .01 lumens total by the math, which would be absolutely visible in total darkness..

How do you know that 0.01 lumens, spread out over an unknown area, would be visible?

It would essentially have to be concentrated enough to put lux on something to see.

Or do you mean you see an application for a light source the size of a 200k pixel camera display working as some sort of 0.01 lumen indicator light, as in the screen sized source would glow faintly, and that would be useful because you could see it if it were otherwise pitch black, and your eyes were night adapted?

:D

I think we can just wait for cold fusion...it should be ready any time now...
 

fyrstormer

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It sounds like it works similarly to laser cooling; when the metal's electron-plasma field is vibrating at its resonant frequency, any input energy increases the brightness of the light emitted -- even if that energy comes from the temperature-induced random vibration of the metal's nuclei.
 

AnAppleSnail

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It sounds like it works similarly to laser cooling; when the metal's electron-plasma field is vibrating at its resonant frequency, any input energy increases the brightness of the light emitted -- even if that energy comes from the temperature-induced random vibration of the metal's nuclei.
I didn't see information about what wavelengths are emitted. Are their lattice vibrations "useful" light, or are we talking infrared warming of an LED here?
 

fyrstormer

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I'm not sure you can get useful light at any wavelength with an input power of 69 picowatts. :whistle: Pragmatism aside, as far as I know an LED will *always* produce its intended color of light as long as the drive voltage is within spec, regardless of how tiny the amperage may be.
 

znomit

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We need to know how big the die is. I'm thinking a few trillion of these mounted to my ceiling to provide light and cooling.

Should save me a few bucks in power.
 
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