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

[FPSRelic]

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

Craig

Apologies

I didn't see your post before I posted. I'll leave the discussion to more knowedgable people on the subject than myself

 

[easilyled]

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.

If you have been following led advancement in technology as long as I have, you'd know that huge leaps in efficiency have been followed by flatter periods of consolidation. Think of a step-pattern graph with efficiency being the vertical axis and time being the horizontal axis.

There have been several giant leaps followed by lulls and there is absolutely no evidence whatsoever to suggest that this won't continue for many more years to come.

 

[csshih]

Apologies

I didn't see your post before I posted. I'll leave the discussion to more knowedgable people on the subject than myself

sorry, I came off as a bit grumpy when I posted!
LED tech has come a long way since the luxeon craze:

I was planning on writing up a more comprehensive/explanatory led emitter index but haven't had the time.

Top Row left to right: Luxeon Lux I LD (low dome), Luxeon Lux III, Cree XR-E, Philips LumiLEDs Luxeon K2 TFFC(philips bought luxeon), Cree XP-G (oops, that xr-e and k2 should be swapped.)
Respectively, 1W, 45 lm (all figures are rough), 3W, 90 lm, 3.5W, 255lm, , 5.7W, 300lm, 5.25W, 460lm

Bottom Row: Luxeon LuxV, Seoul SSC P7, Cree MC-E, Cree XM-L. (the first three are quad dies )
4.8W, 120lm, 10W, 700lm, 9.5W, 750lm, 10W, 910lm.

soon to be added: Cree XB-Ds

Also note: the SSC P7 uses Cree chips (and so does the ssc p4, not pictured)

Craig

 

[ledstein]

Yes, XM-L is old and from looking at the newer MT-G i just hope we get a LED that handles heat much better. If you go deep down into the datasheets there is a graph that shows out lumen flux is affected by heat. As we are mostly hobbyists without any lab equipment we really need to care how a LED behaves when is hot because that flux its is what we actually get.

The XM-L flux goes down to 82% when working at 100C junction temperature...

Anyway until the new Cree LED comes (Light and Building is near, maybe we know then) we can enjoy the drop in prices for the XM-L. Now you can even buy one for as low as 4.90€ as i see on this shop: http://www.ledrise.com/leds/high-power-leds/

Any of you found anything cheaper?

 

[ledstein]

I dont seem to be able to upload the chart image with the flux change at 100C, anyway, here is the link:

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[Kinnza]

If I remember well, Haitz article stated a trend of doubling performance/cost each 18months, and not a constant increase on performance, as we all know (Haitz included) the physical limits of energy conversion into visible light. For many years, LED manufacturers were focused on increasing the performance of LEDs, in order they can compete with other lighting technologies and goes getting into market niches. But once they have reached the 150lm/W figure, now they are focused of reducing prices at the same trend they increased performance before.

Until now, price per LED unit of a given power has dropped very little. Instead, the manufacturers offered a new device emitting more light, but at give or take the same price. It has been a slow decline in price with time, but very small compared with the increase in light emission. Now the focus is on offering the same amount of light at lower prices, and last releases of all main manufacturers clearly points to cheaper packages.

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

I bet I know where that false figure came from. In one of the articles about laser converted white light which arises some months ago, there was a claim of a 70% improvement on light output per burned watt, but on very special conditions which may appear on car headlights: very high current density on the chips and very high power density on the board. On that conditions, LEDs suffer a strong decrease on efficiency, while lasers not, and thus when needed a powerful beam of light, on current state of the art of both technologies, laser converted white may be advantageous.

That situation just happen on conditions where LEDs gets low efficacy (not cited directly on the article) due the operating conditions.

The author of the article surely saw that figure of 70% improvement, took the typical efficacy of white LEDs as reference and calculated the supposed laser converted efficacy. Obviously, it gets a false figure, as the comparison surely was performed with LEDs emitting 50lm/W as best.

 

[saabluster]

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

Craig

Mine don't have phosphor in the dome. Seems people have been confused about this for some time. The phosphor is just applied across the entire surface of the substrate.

 

[csshih]

Mine don't have phosphor in the dome. Seems people have been confused about this for some time. The phosphor is just applied across the entire surface of the substrate.

for both the XT-E and XB-D? I haven't gotten my hands on those yet to check myself. how do they distribute the phosphor over the funky die?

Craig

 

[saabluster]

for both the XT-E and XB-D? I haven't gotten my hands on those yet to check myself. how do they distribute the phosphor over the funky die?

Craig

Well I don't have those either but they appear to employ the exact same deposition as the HEW which I have torn apart and examined.

 

[ledstein]

Whats next?

Cree XB-D, Zhaga like modules, Mt-G II
Philips K 4 to 24 UP

details here: http://www.candlepowerforums.com/vb...t-LED-fair-Cree-Nichia-Philips-Seoul-new-LEDs

 

[bose301s]

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

Craig

You realize LEDs were thin film from day 1 right?

 

[RoGuE_StreaK]

Huh, just received an email from Cree saying that my XM-L sample has been posted... three months after the sample order was approved!! Had just given up and ordered some from LedRise only a few days ago!

 

[csshih]

You realize LEDs were thin film from day 1 right?

forgot the flip chip, duh!

Craig

 

[happyguy82]

Ahh! I didn't realise the XM-L was over a year old already. This means that when SureFire releases their upcoming 500lumens lights such as the DM2, it may not be using the best LED on the market.

 

[SemiMan]

Actually back thinned which is probably more accurate is new for power LEDs developed by Osram an licensed to Cree and Lumileds and others. New being years.

 

[RichLee]

New XLamp® XP-G2 LEDs Deliver 20 Percent Efficiency Increase in the XP Footprint


DURHAM, NC --Cree, Inc. (Nasdaq: CREE) introduces the XLamp®​ XP-G2 LED to deliver luminaire manufacturers up to 20 percent more lumens per watt and 2.5 times the lumens-per-dollar over the original XP-G LED. The brighter, more efficient XP-G2 LED provides customers an immediate boost in performance and enables manufacturers to use fewer LEDs to get the same brightness at lower cost or increase brightness levels using the same LED count and power.
Characterized and binned at 85°C, the new XP-G2 LED leverages the same footprint (3.45mm x 3.45mm) and is compatible optically with the original XP-G LED – providing drop-in-ready performance enhancements to shorten the LED fixture design cycle and improve customer time to market. The XP-G2 LED can enable a broad range of high-lumen applications, from indoor and outdoor to portable and lamp retrofits.
"We have many designs using Cree's XLamp XP-G LED," said William Weiss, partner and director of technology, MSi Solid State Lighting. "The new XP-G2 allows us to take full advantage of the benefits of Cree's latest technology without any significant design changes, improving time-to-market."
Built on the revolutionary SC³ Technology Platform, the XP-G2 LEDs combine high light output, reliability and efficacy to deliver up to 151 lumens per watt at 350 mA, 85°C or 165 lumens per watt at 350mA, 25°C in cool white (both at 6000K). In warm white (3000K), the XP-G2 LED delivers up to 133 lumens per watt at 350 mA, 85°C or 145 lumens per watt at 350mA, 25°C. The SC³ Technology Platform leverages Cree's advanced silicon carbide technology, features advancements in LED chip architecture and phosphor and showcases a new package design to deliver the most advanced lighting- class LED components in the industry.
Luminaire makers seeking ENERGY STAR®​ qualification will have access to specification and performance data, including LM-80 reports, which can speed time to market. XP-G2 LEDs are a "successor" product to the original XP-G LED for LM-80 data – accelerating qualification of luminaires using just 3000 hours of LM-80 data, instead of the normal 6000 hours. The XP-G2 LED is also UL-recognized and features a level 4 rating.
Cree XLamp XP-G2 LED samples are available now and production quantities are available with standard lead times. To locate a distributor or to learn more, please visit www.cree.com/xpg2.

 

[flashflood]

And this thread is now a year old, which makes the XM-L over two years old!

The XP-G2 and MT-G2 are good, but there's still no hint of an XM-L successor. Cree has poured a ton of money into their new silicon carbide platform, but this doesn't appear to be delivering (significantly) more lumens or (at all) better color, just lower cost -- which is great for commercial lighting, but not as relevant for us. I know, I know, we don't matter -- but I really thought we'd be talking about the XJ-Q by now. And complaining that when Cree released the W2 flux bin, it looked a bit green compared to the trusty old V5 and V6.

 

[rambo180]

similar thread:

http://www.candlepowerforums.com/vb...-in-18650-flashlights-and-LED-chip-technology!

 

[mds82]

I've heard there will be a XM-L2 coming out soon as well.

 

[bshanahan14rulz]

I'd rather see a smaller chip with the same output of the XM-L, even at the cost of a funky optical source like the DA series