Cree XM-L is a year old now; what next?

flashflood

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Not to be greedy or ungrateful, but... It seems like the pace of LED improvements has stalled a bit, doesn't it?

The XM-L is about a year old now, and T6 remains the brightest widely available flux bin.

Luminus has not moved the ball since the SST-50 and SST-90, which are a couple of years old. (The CSM-360 isn't what I mean by new; it's really just a 4 x SST-90 package. The point is, same emitter technology.)

Ditto the rest of the field, as far as I can tell: Seoul P7, etc.

So are we on the brink of a wave of new products, or are we stuck because it's getting harder to improve?

We know that Cree has 231 lm/W in the lab, but how far is this from production?

Anyone have the inside scoop on this? BTW, I get LEDs Magazine and even there it's been awfully quiet lately on the fundamental technology front.
 

Harold_B

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I think you might run into an information roadblock since inside scoop often means there's also a nondisclosure in place. Some NDAs are so restrictive that once signed it can't be mentioned that one is working with that company let alone anything about new technology. Getting news beyond the industry mags that have access will be a challenge. Not to say that word won't get out sooner or later!
 

easilyled

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I think XM-L's are here to stay for a good while longer. U2 bins are becoming much more available now.
The XM-L seems an excellent product and I'm not in a hurry for anything to supercede it.
Having to upgrade all one's lights every time a new and better product comes out is a PITA. ;)
 

deadrx7conv

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I'd like to see higher output bins on all the LEDs mentioned here.

And, more availability of higher-CRI choices too in warm, neutral, or daylight white.

SST-50 or SST-90 with 90+CRI, 85CRI...
P7 D-bin has been out a while. Where is the E-bin, or a higher CRI version?
MC-E is available in N-bin. But, that LED isn't mentioned much here anymore. What about higher CRI?

How about a quad XM-L package for those that want 4000lm?

They should also rename the "XM-L" or the "XM-L EasyWhite". Using "XM-L" in two different LEDs wasn't too smart of their marketing department. Its not like we ran out of letters in the alphabet. The "EasyWhite XM-L" looks like a quad XP-E(?) .

The 231lm/w is great for bragging but is useless without CCT and CRI.
 

MichaelW

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Cree should go smaller. They need a 3mm^2 LED in the xm package.
 

richpalm

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SST-50 or SST-90 with 90+CRI, 85CRI...
P7 D-bin has been out a while. Where is the E-bin, or a higher CRI version?
MC-E is available in N-bin. But, that LED isn't mentioned much here anymore. What about higher CRI?

How about a quad XM-L package for those that want 4000lm?

I think all of these have been overshadowed by the XM-L. The couple of SST's that I tried were blown away by the XM-L. With a quad setup, what would you do with heat/amperage in a not-monster sized package?

The difference between now and the Luxeon days is that modern LED's are bright enough in flashlights to see with for a change, even for me, not like a green or purple Luxeon that had to be upgraded every time a newer setup came along. So I wonder if there will be a plateau for awhile.

Rich
 

jtr1962

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I'm sure in the next few years we will see further efficiency improvements as lab research knowledge makes it to the production line. I've little doubt though that future efficiency increases will be smaller, and come at longer intervals. The reason is a richpalm alludes to-LEDs are plenty good enough for a whole host of practical uses at their present state of development. There just isn't as much immediate need to improve them greatly in order to facilitate adoption. LEDs have all but taken over portable lighting applications, for example. And they're starting to work their way into general lighting. I think what we'll be seeing will be more evolutionary than revolutionary.
 

radioactive_man

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The XM-L with its 160 lumens per watt has come a little earlier than Haitz' Law predicted. We may have reached a plateau, or Haitz' Law may need revision.

Let me attempt a quick and dirty revision of Haitz' law: When I got interested in flashlights the XR-E (released october 2006) was the hottest thing in town. This LED had a maximum efficacy of around 85 lumens per watt (someone please correct me, if this is wrong). The XM-L T6 has a max. efficacy of 160 lumens per watt and was released in april 2010, which roughly corresponds to a 88% increase in efficacy in 43 months. This is equal to an increase of 19.3% per year. Cree seems to have already broken the 200 lm/W barrier, so I expect to see LEDs of this efficacy within a year. This prediction agrees with my model, which predicts 228 lm/W two years after the release of the XM-L. However I still think that the development of the XM-L marks a plateau in development, and I don't believe we'll see hotter emitters until about a year from now.

I have an MSc in math and a minor in physics, and I've just extrapolated from a model based on two arbitrarily chosen data points. Somebody please kill me :)

EDIT: And by the way, since the theoretical max. efficacy of a white LED is around 300 lm/W, this model breaks down in a few years.
 
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MichaelW

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Yes! That's what I want to see. Not only that, but, how about an XP-E sized die on an XM package for the throw junkies? Imagine being able to push 2A through an XP-E sized die or 2.5A through an XP-G sized die.

I think the smallest die that can be utilized, without making too much changes is the xp-g's [ez1400]. See the spacing of the triple bond wires. Still Cree could rate that at 2 amps, and the 3mm^2 at 2.5 amps.
 

flashflood

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XP-E HEW, XT-E White, XB-D. Just check Cree's Press Releases. http://www.cree.com/press/pressreleases.asp

C

But still no XM-L successor.

At the time of its introduction, the XM-L was roughly 2.5 times the output of the XP-G and about 20% more efficient. An equivalent technology leap today would be a new emitter with 3.0 Vf, nominal output 1000 lumens @ 2A (170 lm/W), maximum output 2500 lumens @ 6A (140 lm/W). This does not seem out of the realm of possibility given that Cree has had 231 lm/W in the lab for about a year now.

I want my
I want my
I want my MT-V!
 

csshih

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But still no XM-L successor.

At the time of its introduction, the XM-L was roughly 2.5 times the output of the XP-G and about 20% more efficient. An equivalent technology leap today would be a new emitter with 3.0 Vf, nominal output 1000 lumens @ 2A (170 lm/W), maximum output 2500 lumens @ 6A (140 lm/W). This does not seem out of the realm of possibility given that Cree has had 231 lm/W in the lab for about a year now.

I want my
I want my
I want my MT-V!
Your what?

Tech does not scale linearly, nor does Cree soley cater to the flashlight market. I would say that Cree is focusing more on the fixed lighting market as they've been releasing more and more high voltage emitters.
See: XT-E HV, XM-L EasyWhite, MT-G, MP-L, CXA2011, ML-C, ML-E, MX-3S, MX-6S... yeah.
In fact, as we start getting ridiculously lower and lower Vf of LEDs, I bet Cree will purposefully put out higher voltage options to keep efficiency levels optimal.

Anyways - the fixed lighting market will always be much bigger than the flashlight market for obvious reasons. Cree isn't a non-profit organization.

I heard that laser light was the new black in lighting technology. At least, that's what BMW thinks

http://www.autoguide.com/auto-news/2011/09/bmw-to-replace-led-lights-with-laser-headlights.html

For one - that article is terribly misleading. PR probably wrote it and you know how that gets.
In a nutshell-

They are pointing 405nm lasers at a phosphor (instead of blue leds at a phosphor).

However, the numbers that they quoted (100lm/W vs 170lm/w of laser light efficiency), is almost comparing apples to oranges.
Their 100lm/w rating (which is a slightly outdated in the first place) is (probably, I can't predict from what sort of strange places PR pulls "competition" numbers from) a relatively honest figure,
but their 170lm/w rating is complete nonsense (please correct me if I'm wrong). From personal testing, I'm only getting 10-20% efficacy from a 405nm diode (~500mW in, 60mW out), and that's *before - so assuming they have some super premium LDs, I doubt it'll be higher than 20-30%.

Alright, now let's take a look at Cree's current Royal Blue emitters(the base of white emitters). Something modern, in this case the XT-E. at 1A it consumes approximately 3.25W (eyeballing graphs)- and (I'll choose a lower bin to not make BMW PR look bad) and puts out... 1.2W. that's 37% for a non super premium bin emitter (electrical efficiency)

Now, we already established that current incoherent sources are much more efficient - so how did the PR department get their super high 170lm/w figure?

From this information, it seems that their rep was quoting the lm/w figures of the led correctly, but was quoting the lm/w figure of the phosphor conversion of the laser.

I could be terribly wrong, it won't be the first, but BMW isn't a laser company. I doubt that they'll come out with anything super groundbreaking with laser tech.

Craig
 

FPSRelic

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Interesting, but the OP was asking about LED improvements, this being the LED section, rather than a completely different form of lighting technology.

True, so I guess I should clarify by saying that the linked document shows that the reason LED technology has not improved greatly recently is because its reaching the limit of its boundaries, and that a newer technology may be around the corner that replaces led's, just like led's replaced incan.
 

csshih

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True, so I guess I should clarify by saying that the linked document shows that the reason LED technology has not improved greatly recently is because its reaching the limit of its boundaries, and that a newer technology may be around the corner that replaces led's, just like led's replaced incan.

not at all, LED tech is still improving greatly, especially with Cree finally using thin film and remote phosphor.

Craig
 

slebans

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But still no XM-L successor.

Last week I read an interview with someone from Cree management. He stated that the XT-E LED would take them to 200 lumens per watt. When I tried to post this info the LED forum was down. I cannot remember OTTOMH where I found this statement.

Stephen Lebans
 

csshih

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Currently available XT-E/XB-Dss do around 180 lm/w at low drive levels :) as newer bins come out - I'm certain they'll hit 200lm/w.

Unfortunately, they don't do so well in flashlights do to the phosphor distribution (in the dome), and the multifaceted flip chip die.

Craig
 
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