# Another big breakthrough for CREE! 186 lumens per watt!



## Yucca Patrol (Dec 1, 2009)

From today's press release:

Cree, Inc. (Nasdaq: CREE), a market leader in LED lighting, announces it has achieved industry-best reported R&D results of 186 lumens per watt for a white power LED.

This result demonstrates Cree’s continued focus on pushing the performance of its LEDs. Cree’s tests confirmed that the LED produced 197 lumens of light output and achieved 186 lumens per watt efficacy at a correlated color temperature of 4577K. The tests were conducted under standard LED test conditions at a drive current of 350mA, at room temperature.


Edit: at the time of posting, their stock gained $1.75 this morning.


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## clint357 (Dec 1, 2009)

Any more info on what LED it was, or when it will be available?


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## dougmwpsu (Dec 1, 2009)

XP-I available on sept 30th, 2010 with a top bin of 164 lm/w. Press release 2 months later announcing Amazing New Breakthrough! of 211lm/w. xp-k available sept 30th, 2011 with top bin of 189/w. Warm white light nowhere to be found.


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## ifor powell (Dec 1, 2009)

I don't know what the lag is from R&D to production but it would be a t5 bin which is fairly amazing.....

Press release here

Ifor


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## HumanLumen (Dec 1, 2009)

Looking at the fact that te Vf was aprox 3.03V leads me to conlcude that it was not a 1mm2 die, but somthing bigger like the XP-G

HL


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## CampingLED (Dec 1, 2009)

Was expecting some anouncement, but this came sooner than expected. Why I say so is that the XP-G output per sq mm is much lower than the XR-E R2 EZ900 output per sq mm. So, they had the technology to improve the brightness per sq mm on the XP-G. They may be working on the heat issue in the mean time. Just my $0.02. Other than that, well done Cree, my favorate LED manufacturer.


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## jtr1962 (Dec 1, 2009)

I was expecting this announcement fairly soon also given how close the production XP-Gs are to Cree's last lab result ( 162 lm/W IIRC ). 186 lumens per watt is roughly 55% conversion efficiency, meaning only 45% of the power ends up as heat. And 197 lumens at 350 mA would be a T2 bin ( T bins start at 192 lumens if they continue the 30% jump between letters ). If these scale like the XP-Gs, then we're talking ~500 lumens at 1 amp! This all has me thinking U bins ( 250 lumens @ 350 mA ) may be a remote possibility way down the road. 

Note also that they achieved this with a fairly warm tint. 4577K is pretty close to ideal for general interior lighting IMO. Looks like we're within shouting distance of that magic 200 lm/W number. A little work on the Vf ( bring it down to about 2.95 volts from 3.03 volts ), plus a 5% increase in the output, and we'll be there.


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## dougmwpsu (Dec 1, 2009)

What makes 200 lm/w so magic?


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## jtr1962 (Dec 1, 2009)

dougmwpsu said:


> What makes 200 lm/w so magic?


It's magic from a psychological point of view only, just as 100 lm/W was. No physical significance to it however. It's not like we would breaking the sound barrier or otherwise doing something formerly thought physically impossible. The only real physically significant milestone would be when/if LEDs are 100% efficient. At that point there is obviously no room for further improvement.


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## BurmaJones (Dec 1, 2009)

Note the "R&D package" . . . interesting.


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## Al Combs (Dec 1, 2009)

jtr1962 said:


> 186 lumens per watt is roughly 55% conversion efficiency, meaning only 45% of the power ends up as heat.


How is 186 lumens per watt 55% efficient? I thought 683.002 lm/w was the magic number.


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## okashira (Dec 1, 2009)

Al Combs said:


> How is 186 lumens per watt 55% efficient? I thought 683.002 lm/w was the magic number.



Do you want a solid green colored beam for your flashlight?


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## ampdude (Dec 1, 2009)

That is pretty impressive at that color temperature.


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## jtr1962 (Dec 4, 2009)

Al Combs said:


> How is 186 lumens per watt 55% efficient? I thought 683.002 lm/w was the magic number.


683 lm/W is the efficacy of monochromatic 555 nm green light. For any other light source other than monochromatic green, dividing by 683 gives totally meaningless figures which have little to do with how much of the input power to the light source is actually emitted as light, which is what the term conversion efficiency refers to. It is how much of the input power is actually emitted as visible light.


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## blasterman (Dec 4, 2009)

A 4500k phosphor mix is very impressive for that efficiency level, and I will assume we have a typical 80'ish CRI as well. Impressive.

Of course, unless the emitter is the size of a pin head we'll get the typical complaints on how it 'breaks' our current flashlight optics.


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## SFG2Lman (Dec 4, 2009)

damn, i meant to start investing in them before i deployed!


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## Gomer (Dec 4, 2009)

blasterman said:


> A 4500k phosphor mix is very impressive for that efficiency level, and I will assume we have a typical 80'ish CRI as well. Impressive.
> 
> Of course, unless the emitter is the size of a pin head we'll get the typical complaints on how it 'breaks' our current flashlight optics.




These people will only be happy when a TiSaph pumped supercontinuum fiber optic based compact flashlight gets made. (aka, a "white" laser)


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## ltiu (Dec 4, 2009)

Noooooo, there goes my credit card debt again when they release the next batch of lights based on this new LED!


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## Al Combs (Dec 5, 2009)

jtr1962 said:


> 683 lm/W is the efficacy of monochromatic 555 nm green light. For any other light source other than monochromatic green, dividing by 683 gives totally meaningless figures which have little to do with how much of the input power to the light source is actually emitted as light, which is what the term conversion efficiency refers to. It is how much of the input power is actually emitted as visible light.



OK, lets say that 683 lm/w isn't the correct ultimate efficiency ratio. Then what is? You never did say where your 55% efficiency estimate of 186 lm/w came from. The NIST link doesn't explain how they derived the 683 lm/w ratio. But it seems clear it's part of the current day definition for the lumen and the candella. Here is a link with the same 683 lm/w absolute max ratio determined in 1952 with a "standard lamp" and a thermopile to measure the heat loss. Whatever "standard lamp" means, they don't say anything about its being a monochromatic green source. It's more likely an ordinary incandescent light bulb of the day.

If you will excuse the Wiki reference, here's a luminous efficacy table that says LEDs of between 10-150 lumens/watt have between 1.5-22% efficiency. That equals an inferred 100% efficiency ratio of ≈ 681.8 lm/w. The smaller percentage number within limits of resolution is the same thing. There is in the same chart a 500 watt halogen in the chart rated at 19.8 lm/w and 2.9% efficiency. That's a 100% ratio of 682.8 lm/w. I didn't check every number in the chart, but none of the ones I checked were close to your 338.18 lm/w max ratio.


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## BentHeadTX (Dec 5, 2009)

186 lumens at one watt?

Consider a Fenix L2D Q5 puts out 180 lumens at 2.4 watts or 94 lumens at one watt, that means a single AA light can do what the 2AA light does...with the same run time. Throw an optic on that puppy to narrow the beam without making the head larger (assuming it is 2mm sq. die) 

Wonder when the XP-? T5 will be available? I hope within 6 months with optics to match. A single tubular AA helmet light? A 2AA 360 lumen light? A single AAA that puts out over 100 lumens out the front with at least 1 hour of run time? 

Yes, I can wait awhile for the 180 lumen single AA light...woohoo!


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## Al Combs (Dec 5, 2009)

If they ever did develop a superconducting LED, it would no longer require a heatsink. You could have a Preon size light as bright as a P7, running on a AAA battery and it wouldn't even get warm.


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## Freeze_XJ (Dec 5, 2009)

LOL. You know why they call these things _semi_conductor? 

Anyway, i think it's one nice result, and hope it'll show up in our lights soon... Just have to stop that pesky devil on my shoulder that's whispering "2011" (which would still be early enough for any doomsday fanatics squirreling good lights  )


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## jtr1962 (Dec 5, 2009)

Al Combs said:


> OK, lets say that 683 lm/w isn't the correct ultimate efficiency ratio. Then what is? You never did say where your 55% efficiency estimate of 186 lm/w came from.


My 55% is an estimate based on the roughly 330 lm/W of the emitted spectrum which I read is typical for phosphor white LEDs. 186/330 ~55%. It could be more or less depending upon the exact spectrum-you would really need a spectrometer plus software to determine the exact number. However, 330 lm/W is a good ballpark estimate.



> The NIST link doesn't explain how they derived the 683 lm/w ratio.


The 683 lm/W comes from the peak in the eye sensitivity curve, not from tests of any standard lamp. The eye is most sensitive at 555 nm. If you had a light source which emitted monochromatic 555 nm light with no losses, then the efficacy would be 683 lm/W. 683 lm/W represents the maximum theoretical efficacy which any light source can have. But as we all know a monochromatic yellow-green 555 nm light source wouldn't be terribly useful. Generally we want some other wavelengths in there so we can see colors. Any light source which emits light at other wavelengths besides 555 nm will by definition have a maximum possible efficacy of less than 683 lm/W. In the case of white light sources, it is _much_ less. 



> If you will excuse the Wiki reference, here's a luminous efficacy table that says LEDs of between 10-150 lumens/watt have between 1.5-22% efficiency. That equals an inferred 100% efficiency ratio of ≈ 681.8 lm/w. The smaller percentage number within limits of resolution is the same thing. There is in the same chart a 500 watt halogen in the chart rated at 19.8 lm/w and 2.9% efficiency. That's a 100% ratio of 682.8 lm/w. I didn't check every number in the chart, but none of the ones I checked were close to your 338.18 lm/w max ratio.


All they're doing in that chart is dividing the lumens per watt of the source by 683. This is 100% wrong. First, they state that the definition of _overall
luminous efficiency_ as "Artificial light sources are usually evaluated in terms luminous efficacy of a source, also sometimes called overall luminous efficacy. This is the ratio between the total luminous flux emitted by a device and the total amount of input power (electrical, etc.) it consumes. It is also sometimes referred to as the wall-plug luminous efficacy or simply wall-plug efficacy. The overall luminous efficacy is a measure of the efficiency of the device with the output adjusted to account for the spectral response curve (the “luminosity function”). When expressed in dimensionless form (for example, as a fraction of the maximum possible luminous efficacy), this value may be called overall luminous efficiency, wall-plug luminous efficiency, or simply the lighting efficiency."

Nothing wrong with that part. Overall luminous efficiency is indeed the amount of luminous flux emitted ( measured in watts ), divided by the input power ( also measured in watts ). The problem is that in order to calculate overall luminous efficiency for various sources you need to know the efficacy of the emitted spectrum in lumens per watt. As I mentioned earlier, for phosphor white LEDs it is around 330 lm/W give or take. For household incandescent lamps it's around 200 lm/W. For a low-pressure sodium lamp it's about 500 lm/W. For triphosphor fluorescents it's somewhere around 350 lm/W. Once you have these numbers, then it's very easy to calculate the overall luminous efficiency. Just divide the lumens per watt of the source by the efficacy of the emitted spectrum. A 500 watt tungsten lamp would be 19.8/200, or roughly 10%. A low-pressure sodium lamp would be as high as 200/500 = 40%. A 60 lm/W CFL would be about 60/350 = 17%.

My point is that dividing the lumens per watt by 683, and then calling the result "overall luminous efficiency", is wrong. It doesn't represent the fraction of input power which is converted to visible light. In fact, it really doesn't represent anything meaningful.

All this just illustrates why wikipedia can't always be trusted. As much as I'd like to edit that whole table, I have a feeling someone else would probably put it back the way it was again.


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## Al Combs (Dec 5, 2009)

Freeze_XJ said:


> You know why they call these things _semi_conductor?


Good one.


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## blasterman (Dec 5, 2009)

> Anyway, i think it's one nice result, and hope it'll show up in our lights soon


 
Actually there's a part of me that hopes the emitter is an inch across just to watch the flashlight geeks throw tantrums. :twothumbs


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## saabluster (Dec 5, 2009)

blasterman said:


> Actually there's a part of me that hopes the emitter is an inch across just to watch the flashlight geeks throw tantrums. :twothumbs


Who you calling a geek!?:nana:


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## DM51 (Dec 6, 2009)

blasterman said:


> Actually there's a part of me that hopes the emitter is an inch across just to watch the flashlight geeks throw tantrums. :twothumbs


 


saabluster said:


> Who you calling a geek!?:nana:


LOL!


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## zzonbi (Dec 14, 2009)

"All this just illustrates why wikipedia can't always be trusted. As much as I'd like to edit that whole table, I have a feeling someone else would probably put it back the way it was again."

Indeed, I tried to mention the connection between 1/683W, 555nm and 1lm only to have it reverted to the flat 683.002 number (as if those 3 decimals were the key). Also interesting the recent discussion of the article. Not only efficiency is significant as a descriptor for energy conversion, I would also define luminous efficacy as a dimensionless number, between 0 and 1, telling how suited any given spectrum is for conversion to subjective brain signals (or rather through the standard CIE observer response - really a ratio of two areas under two curves). Then photopic lm/W=efficiency*efficacy*683

That said did these new leds got better mostly by being more efficient, or did they also got more efficace, thanks to different spectrums (new phospors or even quantum dots)?

Curious also how the xp-i/k packages would look? Any plans for domeless emitters, for throw freaks?


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## fyrstormer (Dec 14, 2009)

Freeze_XJ said:


> LOL. You know why they call these things _semi_conductor?
> 
> Anyway, i think it's one nice result, and hope it'll show up in our lights soon... Just have to stop that pesky devil on my shoulder that's whispering "2011" (which would still be early enough for any doomsday fanatics squirreling good lights  )


Superconducting semiconductors are not impossible. "Semiconductor" just means it doesn't conduct electricity except in the presence of an electromagnetic field; it has nothing to do with the material's electrical resistance when it is "switched on".

http://www.cellular-news.com/story/37714.php


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## jtr1962 (Dec 14, 2009)

zzonbi said:


> "All this just illustrates why wikipedia can't always be trusted. As much as I'd like to edit that whole table, I have a feeling someone else would probably put it back the way it was again."
> 
> Indeed, I tried to mention the connection between 1/683W, 555nm and 1lm only to have it reverted to the flat 683.002 number (as if those 3 decimals were the key). Also interesting the recent discussion of the article. Not only efficiency is significant as a descriptor for energy conversion, I would also define luminous efficacy as a dimensionless number, between 0 and 1, telling how suited any given spectrum is for conversion to subjective brain signals (or rather through the standard CIE observer response - really a ratio of two areas under two curves). Then photopic lm/W=efficiency*efficacy*683


I had a discussion myself in the talk section about why I feel the whole idea of dividing by 683 makes no sense. The end result may be called "efficiency", but it's relatively useless from a practical standpoint. It doesn't tell you what percentage of the input power to the light emitter comes out as visible light. All it tells you is how well the light source illuminates relative to a perfect 555 nm emitter. This might be academically interesting, but it has no bearing in the real world where most light sources seek to emit white light of some type. I also proposed a revised definition of luminous efficiency as the luminous efficacy of the emitted spectrum divided by 683. At least that makes some physical sense in that you're seeing how efficient at lighting the emitted spectrum is relative to the theoretical maximum of 683. This new definition allows you to see how much of a trade off is made independent of how well the light source actually converts electrical power into visible light. For example, the efficacy of the emitted spectrum of a typical phosphor cool white LED is around 330 lm/W. So by my definition the luminous efficiency would be 330/683 = 48.3%.

I also mentioned that they should consider adding a column with "wall-plug efficiency" to that table. Too many people are confusing luminous efficiency with wall-plug efficiency. Frankly, I wish the existing definition of luminous efficiency would die a quick death as it is stupid and mostly meaningless and confusing. But since some of the authors of that article feel otherwise, then they should put examples of wall-plug efficiency in the table as well in order to prevent confusion. I'm getting tired of hearing incorrect things like a 150 lm/W LED is only 22% efficient at converting power to light, followed by a reference to that article.


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## zzonbi (Dec 14, 2009)

I had a feeling it could be you  I would only name efficiency something which is a ratio of two quantities having the same units, thus being dimensionless, and at most 1. I would also avoid involving it with perception. If we need that, calling it efficacy is less confusing anyway. I could also do without the lumen or candela stuff at all - the watt is enough.

So these 3 figures - efficiency, power and efficacy are pretty much sufficient. Add a spectrum curve too if you want to be exhaustive.

PS if humans evolve to a wider flatter visual perception, only the efficacies would need be revised. True physical quantities, like powers and efficiencies, would stay valid anytime, anywhere (all right, within this eon and parsec ;-).


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## NIMA1966 (Dec 16, 2009)

Look at CREEs SHARE

http://www.bloomberg.com/apps/cbuilder?ticker1=CREE:US


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## kwkarth (Dec 16, 2009)

Yucca Patrol said:


> From today's press release:
> 
> Cree, Inc. (Nasdaq: CREE), a market leader in LED lighting, announces it has achieved industry-best reported R&D results of 186 lumens per watt for a white power LED.
> 
> ...



Really? A warm white, high brightness LED? Awesome!


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## RobEU (Dec 17, 2009)

NIMA1966 said:


> Look at CREEs SHARE
> 
> http://www.bloomberg.com/apps/cbuilder?ticker1=CREE:US



Damn, thats impressive, 100% increase in 5 month time oo:


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## blasterman (Dec 19, 2009)

> Really? A warm white, high brightness LED?


 
Obviously you haven't seen a 450 or 800lumen Bridgelux.  Cree however will certainly blow the other's away with the astounding efficiency of the new technology.




> Look at CREEs SHARE


 
So what. There are a lot of nasty fixtures (and many good ones out there) using Cree's that are contributing to the impending bubble in the green-tech market.

I'd rather have Cree stock at $5 and Cree spending resources to innovate and improve their product than Cree at $50 and dept presidents increasingly doing things to keep their stock prices elevated. Like, newsreleases for products years away from the street. :ironic:


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## Roger44 (Dec 19, 2009)

I'd like to jump in on this thread as I'm getting too high results when calculating CFL lumens/watt, maybe somebody can help me.
If I paste into Excel column 1 the F11 "3-band phosphor" column from this table :
http://www.cis.rit.edu/mcsl/online/CIE/Fluorescents.htm
then the V-lambda eye spectral sensitivity column from this table
http://www.cie.co.at/publ/abst/datatables15_2004/sia.txt
then column 3 = column 1 by column 2 corresponds to the visible light power weighted for the eye's sentivity.
Total col 3/ total col 1 gives the luminous efficiency, but I'm getting a result far too high for a 3-ban phosphor CFL.
If I do the same with a table of incandescent values, I get less than 2% efficiency, multiplying by 686 gives the usual ball park figure of less than 15 lumens/watt for incandescents.
Where has my calculation gone wrong for the F11 CFL?
Thanks.


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## BentHeadTX (Dec 19, 2009)

I think Cree released the stats on the XP-G in March, 2009. I hope the new stuff is only 6 months away as well. Figure it this way, the P3 XR-E was a screamer when released and within 6 months or so, the Q5 showed a very strong improvement that was noticeable. This LED might be the XP-G but Cree has improved the process like they did with the P3 to Q5 bin jump. 

If so, that would make a single AA light as bright as a 2AA Q5 light with the same run time. A S2 bin will punch 400 lumens at one amp so this one would go over 500. 2010 will be an interesting year with the XP-G S2 coming out, the warm whites rolling out and Lumisys in the mix with their mega-LEDs. Maybe by this time next year, a 500 lumen 2AA screamer light will be available. Heck, a single AAA keychain light sitting around 150 lumens would be a paypal moment.


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## spencer (Dec 19, 2009)

I don't think you guys are getting this. There is no product based around this new figure. This is what they have been able to achieve in the lab. My guess is we won't see a product with this efficiency for at least 2 years maybe 3. Not 6 months.


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## blasterman (Dec 19, 2009)

..Which is the reason I explained above Cree is releasing press notes like this.


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## saabluster (Dec 20, 2009)

blasterman said:


> I'd rather have Cree stock at $5 and Cree spending resources to innovate and improve their product than Cree at $50 and dept presidents increasingly doing things to keep their stock prices elevated. Like, newsreleases for products years away from the street. :ironic:


You obviously are entitled to your opinion. Personally I don't see the problem with this one bit. Cree has always been very honest with what to expect and has not made claims they could not back up unlike a couple of the other major LED companies. SSC, Lumileds..cough cough. I think it is good to give your customers an idea of where you are going and what you are capable of.


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## csshih (Dec 20, 2009)

I am truly glad they specifically stated "power LED".


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## znomit (Dec 20, 2009)

Just over a year ago they announced 161lm/W in the lab.

Now 186, so 15% increase.

Meanwhile on the street we have gone from R2 to S2, 28%(at 350mA, better at 1A).

Looks like things are moving from the lab to the flashlights pretty well.


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## zzonbi (Dec 20, 2009)

"Where has my calculation gone wrong for the F11 CFL?"

Looks like the eye sensitivity is given in a cumulative form. I would differentiate that column, then integrate the product column.


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