What is the brightest LED?

TheArcLight

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Mar 14, 2011
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Just curious is there a brighter led than the XM-L right now, and it must be able to be handheld.
 

Th232

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Your question is a bit vague. Are you looking for an emitter, or for an actual flashlight? There are emitters by Bridgelux and Luminus which can output over 4000 lumens, and you can easily still hold an emitter in your hand, or on one finger.

Flashlights on the other hand are a different story. I've seen a flashlight using Luminus' CBT-90 (only 1800 lumens), but no one ever reviewed it. On the other hand, would you consider this to be handheld?

Remember that the smaller you get, not only do you have less room for batteries, but you may toast the LED if you don't limit the time that it spends on.

More information about your requirements would be helpful.
 

jh333233

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LED are like CPU, in high lumen they usually go in a raid, like dual core, quad core in cpu
(SST-50 and 90 is a special case where they just make a big die)
Domestic lighting or spotlighting LED can give a high lumen but bulky as they are a raid of LED chips
Luminus' high power led like CBT is a raid if i didnt forget it
 

WmArnold1

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News of 17,675 lumens from a single LED at 96 lumens per watt (lu/w) was posted on 10/29/11 at CPF here - technically, yes, that's brighter than XM-L (T6) can do: 910.6 lumens at 91 lu/w with sufficient heat sinking..

However, Citizen's LED will definitely not be used within handheld flashlight unless that flashlight also includes a 200 watt active heat sink, as Th232 pointed out for this 8000 lumen "portable" build above.

Whenever we talk about flashlights, I consider hand-held, convection cooled, passive heat sinking ability because the smallest 800 lumen XM-L lights can only dissipate around 5.5 watts without using ice-packs, etc. Subsequently, the emitter is thermally limited to 500 lumens and "brightness" is only relevant for a few brief minutes..

Thermodynamics 101: The maximum sustainable output of any physical light is primarily its emitter's luminous efficacy times the device's maximum heat dissipation capability. For small XM-L lights; that's 91 lumen per watt times 5.5 watts, or, 500 lumens. Generally; if you want to sustain more than 500 lumens with today's technology: buy a physically bigger light with lots of cooling fins. There's plenty of choices in the marketplace. I'm really surprised that nobody has incorporated a fan yet..

I don't know of any emitter with a better efficacy than XM-L in production. However, on 5/09/11, news that Cree achieved 231 lumens per watt was posted at CPF here. Beware tho, they are only testing at 350 mA (around 1W assuming 3.337 forward-volts) and their emitter would need to sustain at least 5.5 watts to float our small flashlight boat. ==> but, if Cree should ever produce that led, it would enable pocket lights that can *sustain* 1270 lumen with the same run-time as today's 800/500 lumen lights! :thumbsup: (don't hold your breath tho..)

P.S. Thermodynamics 201 - efficacy .vs. wall-plug efficiency - it's really complicated! - To keep it simple, my 5.5 watt maximum heat dissipation capability presumes that OTF watts are balanced out by battery/driver heat and that's debatable.. For further study; refer to CPF here.
 
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WmArnold1

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Thanks for sharing your cool info link, @Hind!

Today's top XM-L bin seems to be U3, with an efficacy around 107 lu/w - that's up 17% from the T6 bin and we should see comparable increases in maximum lumens as manufacturers start working U3's into production.

That's really good news to me though, because I thought we would have to wait for a totally new die before we'd realize significant gains like this. :ohgeez:

Have any manufacturers mentioned XM-L (U2) or (U3) yet? Some say it will be *years* before we have U3's in hand..
 

Providence

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I think CMS360 is the brightest led, which is a 4-core led (like the mce)
even brighter than some hid lights.

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yifu

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Thanks for sharing your cool info link, @Hind!

Today's top XM-L bin seems to be U3, with an efficacy around 107 lu/w - that's up 17% from the T6 bin and we should see comparable increases in maximum lumens as manufacturers start working U3's into production.

That's really good news to me though, because I thought we would have to wait for a totally new die before we'd realize significant gains like this. :ohgeez:

Have any manufacturers mentioned XM-L (U2) or (U3) yet? Some say it will be *years* before we have U3's in hand..
A lot of lights on the market specifically use the U2 bin, the SC600 for example. The main issue with current LEDs is that the efficiency drops almost 50% with higher drive currents. For example the XMl U2 and up does around 170 lumens per watt at 700ma but drops to 100+ lumens per watt at 3A. If Cree solves this issue with a, say even lower thermal resistance (i doubt it), the gains would be greater than trying to refine manufacturing techniques, which is what the higher bins involve. @Providence, very nice pics, what type of aspheric lens is that?
 
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