# K2 Emitter from Lumileds



## andrewwynn (May 27, 2005)

I recently acquired some detailed information about Lumiled's upcoming K2 emitter.. so of course i had to make a computer model to see how it will fit in my projects.. it's kinda cute so i wanted to share.. and maybe start a thread to discuss the implications with the new emitter coming. 

The specs show that there are two levels coming.. i call them 'high power' versions and 'low power' versions.. the 'high power' models are designed to run at up to 1500mA and the 'low power' models are designed to run at up to 700mA.. actually it's a little bit confusing because it looks from the specs you could run them all at the higher drive levels.. maybe somebody more in-the-know could help explain that.. 

In any event.. they are going to have 5 brightness bins.. R, S, T, U, and V.. they are similar to the lux 3 in the grouping regarding their output, but the bin rating i think is at the 'base' drive level (which is 350mA for the low-power model and 1000mA for the high-power model.. so this means that the 'S' bin which is rated at 350 actually outputs the light of a Ubin Lux3 when driven at 700mA. 

the R and S bin models are in the 'low power' group and rated from 75 to 100 lumens max
the T, U, V models are in the 'high power' group and rated from 120 to 140 lumens max

(at 350mA.. the R and S are 45 and 60.. at 1000.. the TUV are 80, 100, 120). 

the estimated power to drive the emitters:

The low-power models range from 1.2W on the low side and 2.5W on the high side.. 
The high-power models range from 3.7W on the low side and 5.8W on the high side. 

Looks like they managed to get the average Vf down, and i'm hopeful that the typical K2 will have a Vf similar to the J-bin Lux3 now.. only time will tell where the bins end up.. and how the color binning situation will work out. 

Some very exciting things i think are coming.. with the advent of making them SMD technology and being able to machine-place and solder... i think that the price will be held down from tremendous production quantities possible.

Notice that the emitter leads are much smaller.. and they leave all 4 on.. (the lux 3 is fabricated with 4 leads and two are cut off).. they are going to make K2 emitters with matching leads so they match the footprint of the lux3.. for replacement and possibly easier hand-soldering.

Notice the slug is hexagonal.. i have no idea why, but guessing it makes it easier to machine orient when building, or helps fit into the square body. 

Notice the alignment holes kiddy-corner.... for uber-precise placement.. put a hole in your PCB and put a pin through the hole and get within .05mm centering of your lux!

Notice the one corner not chamfered.. that side is the cathode... technically they say that the chamfered corner is the anode.. but there are 3 chamfered ones so it's backwards from how i'd have done it.

Some size restrictions will come into play with some lights or reflectors that are 'used to' the lux 3 being 8mm diameter.. 

slug size: 5 1/4 mm on the flats.. approx 6 mm to the points.
the chamfered corners fit in a diameter of 8.76 mm
the long corner fits within a 10.35 mm diameter
the emitter leads fit within a 12.15 mm diameter.

The main issue that is affecting my designs is that corner point.. it may not fit in the IMS27 or similar reflector that has a 9mm opening.. it would have to be shaved down to fit, which surely would not be a difficult thing to do.. in a mass-production job like MM.. i would not want to be cutting down each emitter... so i'll be re-designing the reflector to fit outside that 10.35mm diameter... tough call on the IMS 27.. if it's easier to cut the reflector or the emitter, but the emitter would be my bet... fortunately the IMS 17 and 20 only come to the base of the dome, so are unaffected by this issue. 

I have no idea when to expect these emitters to hit the market, but the MM is designed to use and take advantage of several advantages of the upcoming K2 emitter, so i hope they are out by the time MM is ready to go to production.. I will make the prototypes with Lux3s so i don't have to wait.

on the low-power side of the equation.. the S bin model is rated at 60 lumens at 350mA.. that is mind-blowing.. means that if somehow i could get that emitter into a nano it could be double the output.. could be a little tricky given that the insides of a peak head are 8mm diameter.. 

Well that's what i know.. i can see some pretty amazing mods coming from this new emitter.

-awr


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## Xrunner (May 27, 2005)

*Re: K2 Emitter*

Who makes them?

-Mike


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## andrewwynn (May 27, 2005)

*Re: K2 Emitter*

Post updated to include the maker.


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## modamag (May 27, 2005)

*Re: K2 Emitter*

Interesting stuff Andrew. Is this K2 the same as the LuxIV?
Hum... 120 lm from 3W now were're talking!


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## andrewwynn (May 27, 2005)

*Re: K2 Emitter*

never heard the phrase Lux IV.. but logically it might be called that.. 

it takes more like 4-5W to get the full brightness of 120-140 lumen out of the high-power K2, but you can get as much as 100 lumen from 2.5W with the low-power models.. hopefully those will sell for less $. 

-awr


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## evan9162 (May 27, 2005)

*Re: K2 Emitter*

Andrew, 

I noticed in the leaked datasheet that there was no information or warning about not powering the low-power versions at 1500mA.

I have a suspicion that the low power ones merely reflect that they've been tested/binned at that power level. 

It's interesting to compare the typical output values of the different bins (all in white here)...

R: 45 @ 350mA, [email protected]
T: 80 @ 1000mA

So an R and T bins are nearly the same, with R being a tad more efficient and brighter at a given current

S: 60 @ 350mA, [email protected]
U: 100 @ 1000mA
V: 120 @ 1000mA


An S bin is actually more efficient than a U bin, and therefore, brighter at a given current...and it looks like the S and V bins will produce the same output at a given current. 


So, quite honestly, I'd rather have an S bin -12 part over anything else, especially if there's a premium charged for the "high power" -14 parts...


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## OddOne (May 27, 2005)

*Re: K2 Emitter*

Okay, when are these hitting the market? All else is moot until I get my digits on a few. /ubbthreads/images/graemlins/grin.gif

oO


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## PEU (May 27, 2005)

*Re: K2 Emitter*

Only info I can find online: K2 preview 

Pablo


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## andrewwynn (May 27, 2005)

*Re: K2 Emitter*

I've asked for the URL of the source of the detailed PDF, hopefully it'll be posted soon.. 

Evan makes an astute observation.. the S bin -12 is 40 lumen/W at rated output, while the V bin -14 at 140 lumen max output, though brighter costs almost 6W to run so it's 25 lumen/W. 

Think of the implications in multiple-led lights like the tesla-6 etc..

oh.. the -12 and -14 are lumiled's 'tag' to describe the 'low power' and 'high power' models.. '12' for 350-700mA and '14' for 1000-1500mA.. that makes perfect sense to me (not)... that's why i call them 'low power' and 'high power'.

-awr


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## Rossitron (May 27, 2005)

*Re: K2 Emitter*

The details of the K2 have been discussed here before.

Check out lamperich's post for a link to a "leaked" preliminary datasheet.

Nice model btw Andrew /ubbthreads/images/graemlins/happy14.gif


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## IsaacHayes (May 27, 2005)

*Re: K2 Emitter*

evan: I'm confused. An S bin should be 100lumens @ 700ma, but a T bin would only be 80lumens @ 1000ma!? I thought T was greater than S. Do you have the letters switched? But I get what you're saying.

Andrew: does this mean I'll have to make another emitter in photoshop? (see signature) /ubbthreads/images/graemlins/smile.gif


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## evan9162 (May 27, 2005)

*Re: K2 Emitter*

Issac,

Go find the leaked datasheet that lamperich posted (in the thread Rossitron mentioned).

It looks like the -12 parts will be binned/rated at 350mA, whereas the -14 parts will be binned/rated at 1000mA. So, yes, a S-bin -12 part will actually be brighter than a T-bin -14 part, when both are driven at the same current.

gg lumileds - way to confuse the binning game even more.


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## UncleFester (May 27, 2005)

*Re: K2 Emitter*

Hmmm.... Does yaesumofo know about the new slug shape??????


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## IsaacHayes (May 27, 2005)

*Re: K2 Emitter*

Evan: ah, I forgot where the cut off was for the low/high power bin letters. Makes sense now. I guess they are doing this binning and part numbers for these reasons:

1) The K2 is more like an improved luxeon replacement, not really a new product line. Therefore you have the same part that can tolerate 350-1000ma. You can use this part in a 1W application or a ~5W application. But since this is such a wide area of power, there is bound to be some color shifting.... So: They test some at 350, and bin them for color/etc there and name them 12. Then they do some at 1000ma, or whatever, and name them 14. So when a developer needs a luxeon, and wants to drive it at say 1000ma, it won't shift blue b/c it was binned at 350ma, or the other way around and turn yellow...
But technicnally you can take whatever part and run it at whatever you want, but the color may shift from what it was binned at.

2) Seems the new PART number, has spots for the binning structure, and you order with that part number! Like it's built into the partnumber. I wonder if that means anyone could call and say I want this P/N.. ok not avalible, what about this one?

Thats kinda cool, as that's how other companies do it. I know I want a color bin 6 blue, or color bin 1 cyan for sure!!! /ubbthreads/images/graemlins/drool.gif !! That would make it great to nab one!!

UncleFester: not sure, but for certain you'll have to use a hotlips or wait for a new o-sink with the K2's. I wonder if yaesumofo will make a hex slug depression, or have 2 holes and push 2 pegs into them to slide into the emitter's notches???


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## andrewwynn (May 27, 2005)

*Re: K2 Emitter*

I've created a monster :-D

rossitron: thanks re: model.. I can make very precise models.. it really helps when trying to shoehorn things into small places.. i wouldn't do it any other way, they end up looking so cute i have to share.

Isaac.. well the 5W is still a beast.. but i'm really likeing the new K2.. at max power it takes almost 6W to run, so i don't think they will be called 3w or 5w anymore.. 

evan.. like i said.. and you corroborated.. i found no mention you can't run the -12 models at 1500mA.. i think they might just not output the lumens required to binpart them into the TUV group... they do have a much better lumen/watt which helps a lot in small lights with multiple emitters.. or big lights with LOTS of emitters.. i have revisited the 'gigasonic' design and i'm working on a 1200 lumen 12 emitter design.. will have 2hr runtime and i'm going to have a mix of 20 and 27IMS reflectors.. i'm aiming for 40,000 to 50,000 lux.. it will definitely be a force to be reckoned with. 

Issac.. re 100 lumen @ 700 for S and 80 lumen for T bin at 1000.. that is correct.. the difference is that the T when cranked up to 1500 will output 120 lumens.. and i don't believe that will happen with the S.. else the part would be binned higher.

uncle fester: re: slug shape.. i'm guessing that has to do with the likes of o-sink (not sure if he's responsible for that).. the good luck and possibly 'thinking ahead' goes to the fact that a 5 1/4mm hex shape works out to the points fitting in a 5.8 or 6mm circle.. i don't have the exact measurement because they didn't specify the radius.. but looks like the circle that would enclose the hex slug matches the circle of the lux3.. if not somebody should be punished for sure.

Issac.. re binning and color.. that's pretty likely part if the equation.. i have a feeling the lumen output is also part of the equation.. i.e. when they bring a part up to 1500mA and it doesn't output 120 lumen it's not bright enough to be called a "T", so they crank the mA down to 700 and see if they get 100.. if they do they call it an 'S'.. if it's less than 100 at 700 they call it an 'R'.. something like that. 

if CNC milled, the posts could be part of the solid, no need for pins.. pins obviously are easier. For my designs i'm using temporary pins.. the PCB is fabricated with holes.. and pins in most likely a wood board (but i do have a CNC milled aluminum design also).. hold the pcb and emitters in perfect alignment for soldering.

Taking a big of a cue from Mr. B.. and going one step further.. the K2 can handle a LOT higher temps.. which means that the connection to the heat sink is not nearly as critical.. i.e. no need for adhesive contact .. normal arctic alumina will suffice as long as the emitter is held in place.. and you can also get away with sinking the slug to the copper on your PCB as long as the PCB is cooled.. i.e. similar to the 'star'.. you can heat-sink the star.. the emitter is on the star.. but unlike the star.. the PCB does not have to be aluminum. 

I have a very preliminary order in the works to get in line for K2s in quantity for the MM project.. they are claiming 'early summer'.. but I won't be surprised if that means august /ubbthreads/images/graemlins/wink.gif.. I would like to get 900 to 1000 of them.. for the 300ish MMs i'm aiming to make. 

-awr


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## evan9162 (May 27, 2005)

*Re: K2 Emitter*

Issac,

Likely true on both counts. Me, I'd be happier with blue shift than yellow/green shift.

As for the part numbers, I could see the distributors only using the first 8 digits (minus the binning info) - otherwise, they could be stuck with less-than-ideal parts in their inventory. Take for example, the Sandwich Shoppe. Wayne has had TV1K Luxeon III stars there forever - it seems like he can't sell them very easily - but with TWOK or TWOJ stars come in, they sell out rather quickly.

So distributors could get stuck being out of inventory of select binned parts if that's all they're able to sell...or they'd have to leave the binning info off their part listing, and bring the lottery back.

If Lumileds insists on integrating binning info into their part numbers, they should do an appropriate price laddering scheme to give incentive to purchase the lower performing parts - much like processor manufacturers do with different speed grade CPUs.


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## IsaacHayes (May 28, 2005)

*Re: K2 Emitter*

Andrew: I said to drill holes and push in pegs because that would cost less and take less material & time to machine on a CNC. Oh and what is the MM?

Evan: yup, good points. I can't recall the datasheet right now but didn't the 12/14 designation in the P/N come after the binning info in it?

BTW, why does everyone spell my name wrong? I've gotten kind of used to it. Andrew you got it right the first time though, lol.


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## andrewwynn (May 28, 2005)

*Re: K2 Emitter*

I think Isaiah and Isaac are about the two most difficult to spell names.. that's funny (and sad) that i managed to typo the second two times. mea cupla.. oops. 

holes and pegs is definitely cleaner i think.. very similar to the concept of my PCB solution.. 

the MM is my minimighty project: http://mm.rouse.com about 2000 hrs in the design phase.. just about all that is left is laying out the mainboard circuitboard.. it's quite a complex project.. I'm on design #20.. and many of the numbered projects have had an a, b, c.. 

Check out that thread, there will be some very exciting news there soon. 

thirteen CNC parts.. 4 or 5 pcbs.. it uses fatman circuitry with 7 1/2 W capability, but is 1/2 inch thick. 

I have some new pics and hope to post them soon.

-awr


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## ViReN (May 28, 2005)

*Re: K2 Emitter*

12 = 1 to 2 (useful range of) Watts Application
14 = 1 to 4 (useful range of) Watts Application

i.e. "Relatively" "No" Color Shift during the said Watts range. This seems more logical to me... However, I do not have any clue to what they really mean. Its just some what Logical from my POV.


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## Lucien (May 28, 2005)

*Re: K2 Emitter*

That leaked datasheet (if I'm looking at the same one) also lists the red, red-orange, and amber as having a max drive current of 700mA. I wonder if that's going to be updated in light of the recently released Lux IIIs.

Also, pin (lead) 1 and 3 of the 4 lead package are not connected.

The new binning structure is going to be complicated, but I guess we just pick based on what our intended drive current will be, and work from there.

On a related note, do the coloured LEDs also experience colour shifts with drive current? Thus far, my understanding is that this was an issue with whites because of the phosphor.


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## evan9162 (May 28, 2005)

*Re: K2 Emitter*

All LEDs experience color shift with drive current. The white color shift is at least partially due to the blue LED underneath the phosphor shifting spectrum at high current/temperature.


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## IsaacHayes (May 28, 2005)

*Re: K2 Emitter*

Lucien: the K2 red/amber/etc have the same small size die of the 1W part, but can be overdriven to 700ma. This means they will throw farther than the lux1/luxIII versions. Perhaps they will release a K2 with the larger die'd LuxIII red's, and perhaps the current will be double again, but that would be pretty crazy though!!!

Colored LED's aren't too noticble of a shift, but some usually get lower in wavelength as heat/current goes up.


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## WildRice (May 28, 2005)

*Re: K2 Emitter*

about colorshifting, I was scrapping an OLD green 7 segment display that came apart, but before 'filing' it I wanted to check how bright the dies were. This unit was at least 10 years old. Well it went from a sickly green to an almost pure yellow, to orange, then to red... and then back again, albiet a bit dimmer. It would be nice if this effect could be made stable.
Jeff


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## IsaacHayes (May 28, 2005)

*Re: K2 Emitter*

Jeff, Interesting! I guess it depends on what the LED is made of. That increased in wavelength, while Cyan leds will go bluer'r with more current. I wonder if one were to push an Amber luxeon up really high if it would turn orange/red....


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## WildRice (May 28, 2005)

*Re: K2 Emitter*

they do. sadly this means they are NOT happy. I have amber super flux LED's. at 50mA they are yellow, at 75 they start to look orangy, at 100mA, they look REALLY unhappy, really orange.
Jeff


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## idleprocess (May 28, 2005)

*Re: K2 Emitter*

I've updated the LED DB with the Luxeon K2 specs and a host of other newer "power" LEDs.


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## andrewwynn (May 29, 2005)

*Re: K2 Emitter*

Lucien: regarding the pins 1 and 3 not being connected.. i would be a buck that they are.. just like in the lux 3.. that the leads that are cut off almost to the emitter base are connected during fabrication and then just cut off.. i have recovered lux3s on two occasions where i tore off an emitter lead by utilizing the fact that the tiny bit of lead-frame as they call it is electrically the same as the emitter lead on that side of the emitter. I have no idea why they would do this and not say this, but i've seen it before and i'll bet a buck as i said.. they are the same..


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## evan9162 (May 29, 2005)

*Re: K2 Emitter*

Andrew,

Page 14 of the leaked datasheet shows that the two extra pins (in both the 4 leg, and 2 leg versions) are labeled NC.


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## andrewwynn (May 29, 2005)

*Re: K2 Emitter*

Yup..i know.. I just don't believe them.. they also said that the little 'bits' on the lux3 are 'nc' yet they are directly connected to the lead near them.


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## chimo (May 29, 2005)

*Re: K2 Emitter*

I would go with Andrew on this one. They did say the leads were backward pin-compatible with the LuxIIIs on p13 of the datasheet. The LuxIII stars I have seen seem to use the wide lead and the bare emitters seem to use the narrow lead. Has anyone else noticed there are some other leads on the sides of the K2 that are clipped flush to the package? (This may only be in the pre-production run).







Paul


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## evan9162 (May 29, 2005)

*Re: K2 Emitter*

[ QUOTE ]
*andrewwynn said:*
Yup..i know.. I just don't believe them.. they also said that the little 'bits' on the lux3 are 'nc' yet they are directly connected to the lead near them. 

[/ QUOTE ]

Ah, gotcha - I didn't realize that the clipped nubs on a Lux I/III/V were "officially" NC. Guess we'll have to wait and see...


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## andrewwynn (May 30, 2005)

*Re: K2 Emitter*

what a nice picture, thanks for posting.. note that i updated the model to include the detail of the hex shape around the die. for some reason the transparency is not working properly on the gif animation.. arg. 

-awr


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## wquiles (Jun 1, 2005)

*Re: K2 Emitter*

So basically, with the introduction of the K2's, will there be no more 5W (4 dies in one package) as we known them today?

Will


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## IsaacHayes (Jun 1, 2005)

*Re: K2 Emitter*

wquiles, perhaps they may phase out the luxV some day. I think they will be avalible for a while but you won't get many good bins probably... as you can put ~ 5w into a K2 and get around the same lumens as a typical 5w in a smaller area of emitted light.. But in the past we have seen W,X bin LuxV, and I bet output levels of those sorts with the K2 will be rare-to-non-exsistant..


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## yaesumofo (Jun 1, 2005)

*Re: K2 Emitter*

I have a feeling that these are a mere sign of things to come.
Now that I have the data sheet I should be able to start work on the K2 version of the O-Sink. The "Hex-Sink".
Cool. I think there will also be a high power Lumiled part soon 2 or 3 x the k part.
One can always hope.
Yaesumofo


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## McGizmo (Jun 1, 2005)

*Re: K2 Emitter*

I look forward to these LED's but I am as excited as about the S bin at 350 mA as I am at the V bin running at 1500 mA; in some ways more excited about the S. Yes, getting 140 lumens out of a single die will be amazing but we will be paying the price in wasted power and its manifestation as heat to be dealt with. From the preliminary data sheet I got a peek at, you go from 50 lumens/watt with the S at 350 to a best case of 24 lumens/watt with the V at 1500 mA. If I am not missing something, the V bin is pointed at 120 lumens at 1000 mA and an additional 500 mA nets you 20 more lumens. That last bit of light sure costs extra power! /ubbthreads/images/graemlins/icon15.gif

Color shift aside, I wonder what a V bin would yield at 350 mA? Will it be better than a S bin in terms of flux?


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## andrewwynn (Jun 1, 2005)

*Re: K2 Emitter*

The 'S' bin is the bomb.. at 700mA it is 40lumen/watt which is double the output of the current lux3s and the V bin K2 is 'only' 24 or so lumens/watt.... the implications for multi-emitter lights is tremendous.. i have a 'gigasonic' design on the back burner that has 14 emitters.. 1400 lumen and 25,000 lux estimated.


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## idleprocess (Jun 2, 2005)

*Re: K2 Emitter*

Summary of my LEDDB entries on the K2:





I think that there will be more interest in 350/700mA parts than 1000/1500mA parts due to the huge efficiency gap... unless they operate at similar efficiencies at 350/700mA.


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## McGizmo (Jun 2, 2005)

*Re: K2 Emitter*

I joked with Wayne Y that Lumileds probably picks the LED's that are in the bunk color bins and then designates them as the heavy current fellows as the color shift will move them out of where they were! /ubbthreads/images/graemlins/grin.gif It will be very interesting to get a feel of what a V bin will do at 350 or 700 mA!! It may be telling as well to see what color bins are available in what drive levels. /ubbthreads/images/graemlins/icon3.gif


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## ViReN (Jun 2, 2005)

*Re: K2 Emitter*

It's Als Interesting to note that K2 S @ 350 will produce 60 Lumens AND has 50.13 Lm/Watt

Rest of Lm/Watt Figures are just sooo poor.... It looks like they are just "overdriving" and Adjusting/Labeling the Specifications... !

K2 S Bin @ 350 mA is a Real Improvement I think.


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## andrewwynn (Jun 3, 2005)

*Re: K2 Emitter*

the trade off is this.. the relatively crummy lumen/watt rating on the TUV models is countered by the fact they can be driven so hard.. if you have a single emitter light, you can get up to 140 lumens .. which is only a marginal improvement over the 5W emitter, but w/o the drawbacks (big die.. donut hole beam, etc).. and the up-side also is that with the SMD machinable capabilities.. it should drive up the production quantities and keep the prices down.

-awr


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## evan9162 (Jun 3, 2005)

*Re: K2 Emitter*

Well, you can also drive the R and S bins at 1500mA if you want to. I'd venture to say that an R bin at 1500mA is somewhere between a T and U, and an S bin is equivalent to a V bin.


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## NewBie (Jun 3, 2005)

*Re: K2 Emitter*

Keep in mind, the light output levels are with the die at 25 degree C. As the die heats up, the efficiency drops. There is thermal resistance from the die to the slug on the bottom. Makes it impractical to achieve their advertized efficiency level.

But the K2 has a lower thermal resistance than the Luxeon III. Just from that alone, the efficiency is increased (more light output for a given power).

The nice thing about higher efficiency parts, on top of more light output for a given current...is that you also produce less heat in the first place.


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## ViReN (Jun 3, 2005)

*Re: K2 Emitter*

I fully Agree with NewBie.....

and Personally, Given a choice from the above mentioned (idleprocess's List of K2 & it's Figures) I would not like to have any thing other than the S Binned K2 because it will run it at 350 mA from a LDO driven by Li-ion CR123 Battery AND it will produce 60 Lumens AND has 50.13 Lm/Watt(approx) AND will have almost 2 Hours of Runtime !!!

It will have comparitively Less Heat Generation (as compared with the others, being run at just 350 mA) AND hense Less Losses AND Higher Lm/Watt Figures (yes definatell less than 50.. but still better than the other counterparts) AND also the Life expectancy will be far far more (than the other overdriven LED's)... AND the Tj will be relatively lower (so again less losses in Heat, giving relatively More Brightness)

What Else would want more?

It is very Important to consider following Factors and are Highly Desirable
1) More Lumens / Watt (At a Given Temprature... instead of just the Tj=25(practically useless))
2) Higher Light Output 
3) Lower Currents
4) Lower Heat Generation (instead of Better Thermal management).... Remember, Prevention is better than Cure...

K2 S (@ 350 mA) Fits best .... for above factors...


Are there any plans to K2 Star ??? (just curious)


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## Kiessling (Jun 3, 2005)

*Re: K2 Emitter*

Now ... can someone please make a new big nasty diagramm with all the binning info in one place for the LuxI, III, V and K2 as well as color binning, pleeease? /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif
bernie


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## IsaacHayes (Jun 3, 2005)

*Re: K2 Emitter*

Sounds like perhaps a lot of folks will go back to 350ma drive levels and build lights around that as you can have luxIII output levels at that power. ~3w levels for tri-mag mods making the same lumens as we are now! 

Then there will be some who need a super thrower, and will drive the led at max power for 140 lumens in a hig reflector. That would be around double what luxIII mag mods are doing now, allthough your efficiency would be less, but it's a different kind of animal light anyways, for a specific purpose.

I think now more than ever the need for varible drive current setups is needed. Keep it low and bright with long runtime, then ramp it up to full power when you need to reach-out-and-touch something. Then ramp it back down to save power..


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## Billson (Jun 3, 2005)

*Re: K2 Emitter*

But the big question is the availability of the S bin. How does it equate to our current bins. It wouldn't be of much use to us if it was as rare as the Lux III H-vf or U-flux bins.


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## idleprocess (Jun 3, 2005)

*Re: K2 Emitter*

I'll update my "Luxeon Binning" document when more information becomes available.

I really ought to .html it anyway...


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## andrewwynn (Jun 4, 2005)

*Re: K2 Emitter*

I'm a little worried about that 'S' bin's availability.. It will also be very interesting to see how the TUVs perform at lower current and how the RS perform above 700.

-awr


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## Kiessling (Jun 4, 2005)

*Re: K2 Emitter*

So ...

The new K2 R-bin is 45 and the S-bin 60 lumens at 350mA.

In the old days long gone we got R2H high-domes that were binned 39.8-51.7 lumens at 350mA.

What's the deal about these new K2 pieces???

That you might get an S-bin that is a little better than the super-old R-bin?

Or only that you can drive them harder up to 1500mA without damage and that you will be getting 140lm from one emitter?
OK, that's great, but I thought all this talk was about efficiency ... ?????

bernie


----------



## Lucien (Jun 4, 2005)

*Re: K2 Emitter*

I think the gist was that for the older Lux I, the _typical_ luminous output was 40.5 lumens*. Getting a part that would do 50+ lumens would be (far?)less common. The new K2 parts I understand should be able to do 60 lumens typical...

And of course lower thermal resistance, etc. etc.

As everyone is wondering though, it'd be no use if they wave this "60 lumen" figure about, but aren't able to actually supply them in any substantial quantity.

*_I opened up the Lux I datasheet as I had to check this figure and it said 18 lumens typical. Then I checked the date of the file on my HD, it was dated Sept 2002. /ubbthreads/images/graemlins/tongue.gif Things have definitely changed..._

EDIT:_And I thought I remembered the current typical lumen figure was 30-ish. The 40.5 figure is from a datasheet released in April._


----------



## NewBie (Jun 4, 2005)

*Re: K2 Emitter*

[ QUOTE ]
*idleprocess said:*
Summary of my LEDDB entries on the K2:






I think that there will be more interest in 350/700mA parts than 1000/1500mA parts due to the huge efficiency gap... unless they operate at similar efficiencies at 350/700mA. 

[/ QUOTE ]

You should extract a Lux III vs. K2 chart, and also add column for lumen drop due to die heating. There is a huge difference for lumen drop which is much less in the K2, due to the much lower thermal resistance. Assume the slug is at 25 degrees, and adjust your lumen/watt numbers due to the die heating.


----------



## idleprocess (Jun 7, 2005)

*Re: K2 Emitter*

Updated with Lumileds' entire _white Luxeon_ product line - save the "Flash":





Thermal derating is a bit out of the scope of a simple table. Perhaps if I get around to building an actual database...


----------



## SemiMan (Jun 7, 2005)

*Re: K2 Emitter*

In the rest of the world (non-flashlight), I still think people are more interested in lumens\dollar than lumens\watt. If they need lumens\watt and lots of lumens, there are still better technologies. However, when you have LEDS starting to put out significant amounts of light (i.e. over 100 lumens) at a reasonable cost, then efficiency will get more important as the replacement light market will start to become important.

For my flashlight, I am looking forward to having 50 lumens per watt (or more if I run it lightly). 10-15 lumens is often enough for the task at hand. Then when I need it, I can crank it up for a while and get 120 lumens or so. With the 185C die temperature, since I am not looking at it lasting forever, I can keep the heat sink size reasonable too.

Semiman


----------



## andrewwynn (Jun 8, 2005)

*Re: K2 Emitter*

people consider both.. but they don't realize they are considering lumen/watt when the compare run-times of comparably bright lights. 

I think that with the K2 release and those lower power models, that more lights with multiple emitters will be released.. i did the math and the MM should be more than 100 lumen/cubic inch.. that is pretty amazing..


----------



## HarryN (Jun 8, 2005)

*Re: K2 Emitter*

The charts at this stage are interesting, but perhaps not as telling as the real world use will be. A good simple comparison will be to compare Lux III to K2 for T bin and the same Vf (say 3.8V) at 500 and 1000 ma. Regardless of the simple charts, a Lux III will loose big time in Lumens / watt to the K2 in any reasonable heat sink configuration. Lumen losses from heat above 500ma drive currents are quite significant, at least using the TWOKs on my bench tests.


----------



## andrewwynn (Jun 8, 2005)

*Re: K2 Emitter*

I agree.. my latest prototype i made is a 4-up lux 3 in a mag head.. over-driven U-bins to 1200mA.. I left it running 'til the switcher chip overheated .. and after i turned it off for a minute or so i measured the lux reading.. it was about 6000 lux.

I waited about 10 minutes to let it cool down and tried again.. 9550 lux!

I am hoping i am right, but it seems that the coefficient of lumens lost due to heating is about 1/2 that with the K2 compared to the L3.. i have some high-hopes.. i'm not expecting miracles, or necessarily a 'quantum leap', however i believe there will be a significant difference.. especially for certain designs.. specifically the likes of the minimighty. who's designed hard-limited to 2 lux 3's maximum due to the power constraints of the battery/driver.. but with the K2.. I can easily run 3... no matter what the boost of lumens, even if it was zero, i'd get 50% more light.. the reality is that more than likely there will be at least a 20% increase in lumens per emitter in that particular application but also 50% increase in the quantity of emitters.. so the expected boost in lumens is from 160 lumen up to 300 lumen.. almost twice the output for exactly the same power input.. and that is huge.. and helps me get over a pretty elusive goal.. 100 lumens per cubic inch.

-awr


----------



## wquiles (Jun 8, 2005)

*Re: K2 Emitter*

/ubbthreads/images/graemlins/wow.gif

6000 to 9550 lux is a HUGE difference - all due to heat /ubbthreads/images/graemlins/frown.gif

Does anyone has a graph showing the decrease in light output due to heat vs. time? If most uses are brief, folks might not see the huge decreases you saw. I know it would depend on the heat sink and ambient conditions, but I am wondering what is the sweet spot (like 5-10 minutes before you start loosing big time?).

The new K2 does look very promising indeed /ubbthreads/images/graemlins/happy14.gif

Will


----------



## andrewwynn (Jun 8, 2005)

*Re: K2 Emitter*

Well i know that i've never once ever in hundreds of hours used noticed a regulated light dim from this effect.. i notice the output lower during normal use with my LionHeart, and with my pre-nano.. 'resistored' light... so i'm a big fan of using regulated lights.

I was pretty amazed to see the difference in the output level of the RT4 light.. but it's fair to say that the 9550 is more of a fluke that it's cold than the 6000 was a fluke because it was hot.. I only expect about 7000 lux out of the light during normal use.. it's designed to output 7500 and i usually measure between 7000 and 8000 if i let the light warm up a bit before measuring... but i can easily measure between 8500-9000 with a room temperature light.. which is fine anyhow.. because when 'showing off'.. or in real use.. it's the first minute that matters the most anyhow..

That all said.. the RT4 light prototype is pulling 21.6W from the batteries.. and the calculations are such that a light capable of a similar amount of output made with K2 emitters can do the same job with about 11W.. this is a tremendous amount of difference in the power=heat and combined with the lower difference of heat caused loss of light.. I believe that a simlar light will hold the output level more constant not to mention have a significantly longer runtime.

This light I just made was a test-bed for the upcoming K2-based models.. but to get similar light output I am using u-bin emitters and over driving them.. time will tell if those S bin K2s will output the light they are claimed to, but based on the fact that the U-bins i'm using are only outputting 20% more than the T bins that i have, when they are rated to output closer to 30% more, i wouldn't be too surprised if i have to over-drive them to get similar output.. nonetheless.. the heat think will be a big issue and i think it will be a huge help.

I will be starting a thread in a minute about the RT4 and within a week or so i would expect i can get a runtime plot of light output.. maybe not a full runtime test on high.. the light is not meant to be run full power that long.. it has a dimmer for longer runs.

-awr


----------



## idleprocess (Jun 8, 2005)

*Re: K2 Emitter*

HarryN:
If you get your hands on some K2 samples, be sure to test them for us!

About all I (or anyone else) can do is "spec sheet comparisons" for the time being... unless some folks here with samples want to break any NDAs they might have signed.


----------



## Kiessling (Jun 8, 2005)

*Re: K2 Emitter*

idle ... thanx for the table /ubbthreads/images/graemlins/thumbsup.gif /ubbthreads/images/graemlins/bowdown.gif

Now ... LuxV X-bin is still among the best, and it sports quite old technology, as does the LuxI R-bin.
OK, you can drive the K2 harder and get more total lumens, but the price per lumen is still the same it seems ...

bernie


----------



## yaesumofo (Jun 9, 2005)

*Re: K2 Emitter*

[ QUOTE ]
*UncleFester said:*
Hmmm.... Does yaesumofo know about the new slug shape?????? 

[/ QUOTE ]

I do know about the new slug. I am awaiting the official spec sheet from Lumileds. Samples to follow. I will be working on the hex sink as soon as I have official data. With a little luck, ok, a lot of luck, the Hex sink will be available around the same time the K2 hits the market.
Yaesumofo


----------



## Sway (Jun 9, 2005)

*Re: K2 Emitter*

[ QUOTE ]
*yaesumofo said:*

With a little luck, ok, a lot of luck, the Hex sink will be available around the same time the K2 hits the market.
Yaesumofo 

[/ QUOTE ]

/ubbthreads/images/graemlins/poke2.gif Any idea when this will be, Lumileds release says summer and it has felt like that here for the past several weeks /ubbthreads/images/graemlins/mpr.gif

Later
Kelly


----------



## HarryN (Jun 9, 2005)

*Re: K2 Emitter*

[ QUOTE ]
*Kiessling said:*
idle ... thanx for the table /ubbthreads/images/graemlins/thumbsup.gif /ubbthreads/images/graemlins/bowdown.gif

Now ... LuxV X-bin is still among the best, and it sports quite old technology, as does the LuxI R-bin.
OK, you can drive the K2 harder and get more total lumens, but the price per lumen is still the same it seems ...

bernie 

[/ QUOTE ]

Hi Bernie

I am not sure what the price for K2 will be, but assuming equivalent price per part to a Lux III (??), I am strongly expecting that 1000ma driven through a similarly rated K2 and Lux III, the K2 will in fact put out more ACTUAL Lumens, so the Lumens / $ will be bettter. Bottom line, the specs are more realistic.

Idle - When I get some K2's, they will get the HarryN torture test (not scientific, just abusive), then they will go into some lights I am building. /ubbthreads/images/graemlins/smile.gif (which already have a PCB on order which can handle the Lux III, Cree X lamp, and the K2) /ubbthreads/images/graemlins/smile.gif


----------



## tvodrd (Jun 9, 2005)

*Re: K2 Emitter*

A year and a half+ ago, I was at an engineering tradeshow. I stopped at a metal parts manufacturer's booth when I saw some Lumaleds raw mechanical parts. The guy showed me some proto hexagonal bare slugs(!) that were not on display. He didn't know anything, and when the first LuxIII's hit the street, it wasn't them! Imo, the hexagonal aspect of the slug will have no effect on heatsink design for anybody. Look at the bottom of an emitter and "picture" the slug being hex-shaped. /ubbthreads/images/graemlins/icon3.gif

Larry


----------



## andrewwynn (Jun 10, 2005)

*Re: K2 Emitter*

the hex shape is definitely part of the preliminary specs.. quite specific about some aspects of the size of it etc. An interesting thing is that the spec for the size of the hex slug is bigger than the size recommended for the solder mask below it.. it looks like the intent is that the solder mask insulates the slug from the copper ground plane.. i'd like to know if that's the fact or not.

-awr


----------



## yaesumofo (Jun 10, 2005)

*Re: K2 Emitter*

Larry, I am not sure I agree with what you said here. From my perspective there certainly will be a change needed.
The O-Sink design is made specifically for LUX III emitters and allows for perfect centering and locking placement of the emitter on the heat sink. Due to the change to a hexagonal shape of the slug a change in design will certainly have to be made to accommodate the new K2 slug shape to achieve the same centering and locking of the emitter into the heat sink.
yaesumofo

[ QUOTE ]
*tvodrd said:*
Imo, the hexagonal aspect of the slug will have no effect on heatsink design for anybody. Look at the bottom of an emitter and "picture" the slug being hex-shaped. /ubbthreads/images/graemlins/icon3.gif

Larry 

[/ QUOTE ]


----------



## andrewwynn (Jun 10, 2005)

*Re: K2 Emitter*

it actually looks like the hex points will match the original circle.. if they had their brains turned on when designing it.. it could not be different.. 

however.. i think it would be very sexy to have a purpose-built version and have considered making my universal heatsink designed with matching hex slugs and i really liked it a lot.. but it's harder to machine the matching parts.. introducing 'points' makes cnc mills very unhappy. Once i get an actual spec on that radius or a K2 sample to measure things can be different.

I think the bigger problem for things matching up will be the square shape of the body.. it looks like the K2 wouldn't fit on the O-sink because of the depth of the dent.. also.. not sure about it fitting into the reflector of the stock maglight.. i'm curious about that. 

-awr


----------



## yaesumofo (Jun 10, 2005)

*Re: K2 Emitter*

[ QUOTE ]
*andrewwynn said:*
I think the bigger problem for things matching up will be the square shape of the body.. it looks like the K2 wouldn't fit on the O-sink because of the depth of the dent.. also.. not sure about it fitting into the reflector of the stock maglight.. i'm curious about that. 

-awr 

[/ QUOTE ]

More will be revealed when the official documents arrive. I am expecting samples to follow.
Personally I would like to get away from the mag reflector anyway and go to something that is tighter to the emitter. That will kill the focus but I am pencil beam guy anyway. Lets just hope the emitter fits on the end of the pedestal. if it doesnt then a major system redesign will be needed. Or of course we can just use the Better binned LUX III's when they come down the pike for the mag mods. It is all about weather or not the emitter fits on the top of the pedestal. I will know soon.
Yaesumofo


----------



## yaesumofo (Jun 10, 2005)

*Re: K2 Emitter*

BTW having just done a measurement I am confident the K2 emitter will fit and function on a O-Sink (HEX) with no problem. The pedestal is 14.5 mm wide plenty of room for the 8.5mm wide K2.
The slug size is different with the k2's slug being 5.25mm (I hate mm's much prefer inches so does my machine shop) I believe the Lux III slug is 5.2mm a little smaller than the k2.
Yaesumofo


----------



## andrewwynn (Jun 10, 2005)

*Re: K2 Emitter*

the 5.25mm is the 'flats'.. i don't remember what i measured on the L3 slug but i think it's close to 5.9.. and the points of the hex appear to match almost exactly.. i.e. 5.9 'dent' will fit either the L3 round or the points of the K2.. the long point of the K2 measures about 10.3mm diameter. 

5.25=.2067
5.9 = .2323
10.3 = .4055

thousandths is a lot harder to design with compared to 'whole numbers' of mm.. but when the machine gear is all labeled in 000s.. yeah i'm sure it's harder to machine.. so i design in MM myself, but when done it's no biggie to convert everything to inches for machining.

-awr


----------



## IsaacHayes (Jun 10, 2005)

*Re: K2 Emitter*

I'm pretty sure the emitter will fit in the mag reflector. I think that a circle with the same diameter as the hex would be the way to go. Maybe even pegs for the case but I think that there might not be room on a single mag sink style HS. For multiple ones in the head then yes pegs sound nice.

yeasumofo, any progress on the intergrated HS/Reflector pencil beam project?


----------



## yaesumofo (Jun 10, 2005)

*Re: K2 Emitter*

[ QUOTE ]
*IsaacHayes said:*
yeasumofo, any progress on the integrated HS/Reflector pencil beam project? 

[/ QUOTE ]
Isaac, I don't want to draw this thread too far off topic but suffice to say that the O-Sink integrated reflector project is still on the rails. At the moment I am working on several different things. At the moment my focus is on the New HEX-Sink for the K2, with other projects to follow. Thanks for asking. To get this on the point again. The whole idea behind the integrated reflector is to have a reflector where just the dome of the emitter fits into the reflector, a large maglight size reflector. The K2 emitter with it's pin alignment system is a great candidate for this because those same alignment pins can be used to support/align the reflector.
Yaesumofo


----------



## Former_Mag_User (Jun 25, 2005)

*Re: K2 Emitter*

Will the K2, driven at 1000mA outshine a LuxV?

EDIT: It seems like it will.


----------



## McGizmo (Jun 25, 2005)

*Re: K2 Emitter*

Since the K2 slug can now be soldered to the heatsink, I suspect that if it is offered on a star, we may want to avoid the stars if the intent is to remove the emitter. /ubbthreads/images/graemlins/icon15.gif /ubbthreads/images/graemlins/icon3.gif


----------



## andrewwynn (Jun 25, 2005)

*Re: K2 Emitter*

the T, U, V K2s are rated 120, 130, 140 lumen at 1500mA.. and 80, 100, 120 at 1000mA the V is rated 120 lumen, i think at 1000mA, but could be 700 or 750, i forget. 

a lux V at 1000mA is about 6.8W... a K2 at 1000mA is 3.7W, but at 1500mA is 5.8W. 

I didn't see that the slug can be soldered, but i suppose if there is bare metal below the slug and it's wave soldered it would be, huh? 

it will be interesting to see what and if they make stars.. the star's point is to simplify assembly.. the K2 is SMD so there is much less point of a 'star'. anybody know the answer? 

-awr


----------



## alfaman (Jun 25, 2005)

*Re: K2 Emitter*

hi all,
the K2 will have the same star HS as current models - quote from firm source in San Jose. /ubbthreads/images/graemlins/smile.gif


----------



## McGizmo (Jun 25, 2005)

*Re: K2 Emitter*

alfaman,
If the HS is the same with Al under the slug, then I would assume an adhesive bond. /ubbthreads/images/graemlins/thumbsup.gif Me thinks that assuming and Lumileds in the same sentence is a sure path to the unexpected! /ubbthreads/images/graemlins/grin.gif


/ubbthreads/images/graemlins/popcorn.gif


----------



## andrewwynn (Jun 25, 2005)

*Re: K2 Emitter*

oh.. yeah really good point.. aluminum star = solder no workie.. definitely will be bonded with 2-part thermal adhesive. However.. i am very curious about how in the datasheet.. they say to make the solder mask SMALLER than the heatsink hex... i think that this is their clever way of making sure the slug can be electrically isolated from the copper ground plane which they recommend maximizing under the slug.. a dab of heat paste to get the heat out, but the thickness of the solder mask to keep it electrically isolated by a few thousandths of an inch.


----------



## wasBlinded (Jun 26, 2005)

*Re: K2 Emitter*

I just received one of the 'new' LuxV emitters with a round slug contact that came with a Lumileds star heat sink to be used if needed. While the HS is aluminum, the slug contact point on the HS is copper. FWIW.


----------



## McGizmo (Jun 26, 2005)

*Re: K2 Emitter*

wasBlinded,

The HS you describe is what I would assume for the K2. They can solder the slug to a sink plane that can radiate out in areas not needed for the lead wire traces and pads and likely get a superior transfer to the Al core over their previous adhesive bond. I would assume that slug and leads would be soldered in the same operation and save on assembly time. /ubbthreads/images/graemlins/icon3.gif Still assuming though! /ubbthreads/images/graemlins/grin.gif

The ease with which some of the LuxIII's pop off the star and the lack of any residual adhesive in some cases makes me suspect the adequacy of some of these stars! It also gives me a plausible suspicion as to why the slug on the emitters is now extended further below the case and presumably held to better tolerances. /ubbthreads/images/graemlins/thinking.gif If one were to ask why the change in the slug on 5W and LuxIII, I would offer a guess.


----------



## alfaman (Jun 26, 2005)

*Re: K2 Emitter*

hi bros,

if you are still hunger for K2 exclusive info, go google for a random lumileds' staff email address and contact them.
chances are they are more than willing to entertain you.
that was how I got the news on HS.
I was also told K2 will only be ready for sale late 2005.


----------



## idleprocess (Jun 27, 2005)

*Re: K2 Emitter*

Late 2005 is better than what I've been hearing.

I dissected the datasheet in this chart, posted earlier in this thread.

The same data is in the LED DB, linked in my signature.


----------



## McGizmo (Jun 27, 2005)

*Re: K2 Emitter*

If the Lumileds folks are lurking, *Please* loose the one full corner on the K2!! /ubbthreads/images/graemlins/rolleyes.gif Surely some other means of anode/cathode identification can be employed and a concentric package could be offered? /ubbthreads/images/graemlins/icon3.gif


----------



## alfaman (Jun 27, 2005)

*Re: K2 Emitter*

Idle,
The fact is K2 won't be ready in 05'
I couldn't believe my ears after all the harping in CPF.
what? another 5 months?!


----------



## IsaacHayes (Jun 27, 2005)

*Re: K2 Emitter*

Don, why the need for concentric package?

I guess upgraded tri-mods and single emitter throwers will have to wait. Good, I have no money now. But if they have a few cyan color bin 1 K2's sitting around I'll take those now...


----------



## McGizmo (Jun 27, 2005)

*Re: K2 Emitter*

IsaacHayes,
For me the easiest way to center a part in a concentric host is to have a concentric reference. The slug can be used but it is relatively shallow and smaller in diameter than the package . One has to allow for tolerances in dimensions and the larger the dimension the less effect the same tolerance has on the relative positioning. To exaggerate, +/- .005" in a hole that is 1" in diameter will feel and seem much less "sloppy" than +/-.005" in a hole that is .100" in diameter. 

To modify existing hosts for the K2, it is one thing to bore a larger diameter hole to accept the package. The K2 now requires a larger diameter hole as well as a milled relief for "Jack's" pointed hat! /ubbthreads/images/graemlins/tongue.gif

In some builds, I have used the lens of the LED as a centering reference with the aid of a centering jig. The soft gummy bear lens of the K2 is not something I would want to be using for moving the LED towards center. /ubbthreads/images/graemlins/icon3.gif (don't ask cause I won't answer!)

According to alfaman, these LED's are far enough down the road that the landscape may well be very different when the time comes anyways! Lumileds and Future have some competition in the wings and next season may see some new players!


----------



## andrewwynn (Jun 27, 2005)

*Re: K2 Emitter*

the point is ludicrous IMHO.. it really makes it a problem for retrofit.. the K2 will not fit into a lot of reflectors (i.e. IMS27) specifically because of the point.. it's also on the wrong side! (the only 'differen't' corner is on a NC lead... not on + OR -... the positive side is denoted by the absence of the point... which happens to be THREE of the points.

from a mechanical perspective the 'chamfered' corner is ideal for machine placement.. but it should be square on 3 corners and chamfered on only ONE.. but that would suck for building reflectors around it, but doable other than the AAA size. 

fortunately it's just plastic and i can dremel it away but that does not work for production runs just 'modders'. 

Ouch on the 'don't ask'.. i did see in a recent spec 'silicone' lens.. whoa.. never thought about it being soft... hmm. i kinda like the hard lens, what kinda problems will this cause for us. 

well my designs have space including the 'point' but one design could not handle 'square'.. so glad the other three corners are chamfered... I think they are 'set' on having the point, and i sure hope i could get my grubs on a few samples for my prototypes.

-awr


----------



## andrewwynn (Jun 27, 2005)

*Re: K2 Emitter*

addendum.. looking at specs on the K2 again.. they are very keen to point out that the sides of the K2 are not to any particular tolerance, and to align use the pins.. which i believe are exactly centered exactly 3.0mm over and 3.0mm up from the dead center of the emitter.. (and the other is of course 180 deg. from there)... the 3.0 could be just a coincidence.. i think the spec is the distance from center at a 45 deg. angle.. i just know i built my model from the pdf and that's where the hole ended up. 

-awr


----------



## IsaacHayes (Jun 28, 2005)

*Re: K2 Emitter*

Don, ah, I see. I'm used to eye-balling and hand centering things. So far all of my mag mods have been perfect or 98% so...

Silicone lens? So it doesn't fade from sunlight? Come on! I use the lens to lightly press down when setting epoxy... This will make these super fragile!!! yeesh!


----------



## Former_Mag_User (Jul 8, 2005)

*Re: K2 Emitter*

Any news or updates? /ubbthreads/images/graemlins/icon23.gif


----------



## andrewwynn (Aug 24, 2005)

*Re: K2 Emitter*

last newsflash i got was a clue that they will be in mass production Q2 of 06... not too surprised.. i was expecging spring.

-awr


----------



## 3rd_shift (Aug 24, 2005)

*Re: K2 Emitter*

As long as they don't make the slug (+) like they did in the Luxeon3 R/O fiasco, then it will be worth the wait. /ubbthreads/images/graemlins/smile.gif


----------



## andrewwynn (Aug 24, 2005)

*Re: K2 Emitter*

yeah what the heck was *that* about? well the reality is.. you are supposed to isolate the slug in ANY luxeon so as long as you do a good job no biggie.. i did notice that with the amber emittesr.. they use a different type of junction where the bond wire comes in from the top rather than from the side so it's a 'gimme' that the slug would be either neg or pos.. but how about a WARNING rather than just a generic 'it's not neutral'... 

"it's HOT" is decidedly different than "it's not electrically neutral"!

the white emitters as far as i know all use the same type of junction so should be the same isolation issues (i.e. even though they are not supposed to be grounnded.. likely can 'get away' with common chassis ground on white slugs in series. 

-awr


----------



## evan9162 (Aug 24, 2005)

*Re: K2 Emitter*

Actually, you can't get away with series luxeons with their slugs being common. Several people have reported trying to run series luxeons with the slugs tied to a common ground, and end up with only one lighting, or flickering/intermittent operation from the others due to partial contact.


----------



## HarryN (Aug 24, 2005)

*Re: K2 Emitter*

[ QUOTE ]
*evan9162 said:*
Actually, you can't get away with series luxeons with their slugs being common. Several people have reported trying to run series luxeons with the slugs tied to a common ground, and end up with only one lighting, or flickering/intermittent operation from the others due to partial contact. 

[/ QUOTE ]

I second that experience.


----------



## McGizmo (Aug 24, 2005)

*Re: K2 Emitter*

What HarryN said! And not only will the red LED slug be +, it might be gold plated as well! Unless you need a tiny point source of light for collumation on the red and R/O, I think the luxIII's will be a better choice for overall output but in any case, got to keep them cool or wave goodbye to the flux.


----------



## tvodrd (Aug 24, 2005)

*Re: K2 Emitter*

Dumb---->tvodrd!

Larry


----------



## IsaacHayes (Aug 24, 2005)

*Re: K2 Emitter*

andrew: I think you meant slugs in contact in parallel, not series.


----------



## andrewwynn (Aug 25, 2005)

*Re: K2 Emitter*

i'm sure i said something wrong.. what i *meant* was that a set of series connected white luxeons i thought i heard could have a common connection of their slugs.. as long as that connection was not connected to hot or ground.. a floating ground... i personally would isolate EACH of the slugs but i thought i heard you didn't have to.

-awr


----------



## HarryN (Aug 31, 2005)

OK, I received a pair of proto K2s - as you might expect, they are slightly different than what I thought the data sheet said. The slug is VERY short - almost too short for self centering, but great for auto SMT equipment. (too bad I don't have this) I think they are similar in this regard to comments made re the new Lux III slug size.

Have not had a chance to turn this on yet - but coming soon.


----------



## nemul (Aug 31, 2005)

HarryN said:


> OK, I received a pair of proto K2s - as you might expect, they are slightly different than what I thought the data sheet said. The slug is VERY short - almost too short for self centering, but great for auto SMT equipment. (too bad I don't have this) I think they are similar in this regard to comments made re the new Lux III slug size.
> 
> Have not had a chance to turn this on yet - but coming soon.




sweet more more


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## IsaacHayes (Aug 31, 2005)

andrew: ok, well, your're wrong. if they were in parallel, though, then it would be ok for slugs to be common negative connected. as all the negative leads are wired to the same wire goign to the battery. Now series it would be different...

Harry: Hmm, photos of the slug? Well if you can't do that, tell us how they perform as best as you can!!


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## McGizmo (Aug 31, 2005)

Here's an image of a gold plated slug on a red K2. I tried a recessed counter bore of 6 mm diameter to center on the rounded points of the slug but as suggested above, the height is not really enough for a good reference and once a thermal epoxy or grease is aded to the shallow depression, the detection of the pocket is even harder to notice. :shrug: I agree that if one was to mount one with the SMD equipment, it would be a piece of cake but even then, you now have some type of PCB that needs thermal transfer.


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## IsaacHayes (Aug 31, 2005)

hmm the slug doesn't extend eh... Well, I guess we'll have to use the cut out corner tabs for alignment with pegs after all. Does anyone have any samples of green/cyan/blue K2's yet or all the samples reds? I wonder when you can order the colored K2's, since those will most likely be avalible first.. I want a cyan 490nm of course...


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## andrewwynn (Aug 31, 2005)

the spec sheet for the lux3 says that the slug is not electrically neutral but that's ambiguous if can be connected to a common floating ground... i.e. yes you can't connect them to positive or negative.. but can 3 emitters have their slugs electricaly connected if their anodes and cathodes are connected so as to put them in series. 

normally the emitters are attached with a non-conductive epoxy but the new K2s will be sometimes soldered on.

I think it may be pretty clear that holes and pins will be the way to go for aligning K2.. i think a 1.0mm rod is exactly the size of the diameter of the top of the hole, so you could put 2 1mm holes and use a temporary pin for alignment .. that's my plan for minimighty and bam.

very exciting that people are actually getting samples.. just got my form in the mail today... whoo hoo.

-awr


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## evan9162 (Aug 31, 2005)

andrewwynn said:


> very exciting that people are actually getting samples.. just got my form in the mail today... whoo hoo.
> 
> -awr



Is there a form to fill out for samples??? ooh! ooh!


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## IsaacHayes (Aug 31, 2005)

andrew, the way series works you can't have the slugs common, as they are tied to the negative for the white/green/blue luxeons. Series is wired like this: Gnd...-lux+...-lux+...-lux+...Pos. It would however not affect parallel wiring, as every lux negative lead connects to the gnd wire, and every pos lead, connects to pos in. So if their leads are all common, it wouldn't matter if their slugs were all common. Hope that makes some sense... :shrug:

To answer your senario question:
If you have say 3 luxeons in series, and the HS is isolated from ground or postive, but the slugs of the luxeons are all connected to eachother through the HS, then you will still have problems. Why: (white/blue/green/cyan) luxeons slugs are connected to the negative lead. (amber/red/ro) slugs are connected to the pos lead. The white/blues don't have much problem usualy as the HS's are tied to negative, or people use parallel configurations. Also, you can't measure resistance through their slugs because they have a diode I belive so you can't just use your DMM and touch the neg lead and slug and get a reading. You can howerver do that with a (red/amber) luxeon on the postive lead as there isn't an ESD diode in them. (I guess they are more resistant to ESD than the blues)... SO! in series, keep the slugs away from pos/negative power source, and keep them away from each other! (away from electrical path) 

evan: if you fill one out, request blue/cyan if you can... more closer to white... And if you get cyan send it to me, er what? yes ok you can do that sure that'd be great!  :nana:


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## HarryN (Aug 31, 2005)

IsaacHayes said:


> hmm the slug doesn't extend eh... Well, I guess we'll have to use the cut out corner tabs for alignment with pegs after all. Does anyone have any samples of green/cyan/blue K2's yet or all the samples reds? I wonder when you can order the colored K2's, since those will most likely be avalible first.. I want a cyan 490nm of course...



Isaac - I think you might still be underestimating the challenge of using these by hand mount. I have almost exactly the same concept going as Don posted - but it painfully does not really work very well.

The pin type centering holes can be useful, or useless, depending on whether or not you are willing to throw away your old boards for Lux III and Cree and make a dedicated K2 board. It is also useful to note that PCBs often do not have the dimensional tolerances of machined Al parts. To me, this just makes the centering problem worse.

K2s cannot yet be purchased, they are being sent in very small qty to corporate customer accounts by special arrangement as engineering samples.

I am not an expert on the Lux III slug / electrical setup, but at least for white, I have tried a resistored setup where I attached the slug to + and - (not at the same time) and it did not seem to make any difference. No idea why, or I was just lucky. Of course, this gets more complex when you have multiple floating voltage and grounds.


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## IsaacHayes (Aug 31, 2005)

Harry, I agree we are going to have to create new HS/centering things for the K2. I was refering to an alumium HS. I don't work with lights that use pcbs, so I don't have input on that... But yes we can't adapt exsisting stuff to use the K2. We have to design new... But I'm sure we will.... BTW was your sample a red as well?


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## evan9162 (Aug 31, 2005)

IsaacHayes said:


> andrew, the way series works you can't have the slugs common, as they are tied to the negative for the white/green/blue luxeons. Series is wired like this: Gnd...-lux+...-lux+...-lux+...Pos. It would however not affect parallel wiring, as every lux negative lead connects to the gnd wire, and every pos lead, connects to pos in. So if their leads are all common, it wouldn't matter if their slugs were all common. Hope that makes some sense... :shrug:



Actually, the slugs aren't connected to ground - there are two ESD protection diodes connected from the slug to each power terminal. If you use the diode test function, with positive on the slug, and negative on either terminal, you will forward bias the ESD diode - it should show about 0.7V.


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## HarryN (Sep 1, 2005)

IsaacHayes said:


> Harry, I agree we are going to have to create new HS/centering things for the K2. I was refering to an alumium HS. I don't work with lights that use pcbs, so I don't have input on that... But yes we can't adapt exsisting stuff to use the K2. We have to design new... But I'm sure we will.... BTW was your sample a red as well?



Mine are white. The slug is a silvery color.


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## IsaacHayes (Sep 1, 2005)

Evan: hmm. interesting. I always thought they were negative biased.. :shrug: Well I do know for a fact the reds are pos biased slugs. I can see that with my eyes!  

Harry: white, cool. Have you tried to fire it up yet and compare it to some luxIII's? I see you have more than one... lucky dog!!


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## DSpeck (Sep 2, 2005)

Where can I find the datasheets, now that the samples are at least trickling out? Basically, I want to have the locating pin placements, and the solder pad locations.


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## HarryN (Sep 2, 2005)

I have an expired data sheet that I can email - send me a pm. Also, I think there is another K2 thread with a link by - maybe it was idleprocess ?


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## Burnt_Retinas (Sep 4, 2005)

So what's the real truth regarding the slug connection?. If what evan is saying is correct, then the K2's can be connected in series with a common slug connection for all LED's of the type his comments applied to. This of course means that the common slug/s connection point (heatsink etc) must always be connected to the negative supply or floating, NOT the positive supply. This would ensure all ESD diodes are reversed biased at all times during operation, other than an ESD discharge of course.

Wish I had some to tinker with.

Chris


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## HarryN (Sep 4, 2005)

I don't have enough to run tests which might damage the K2, so I am focused on building one up in my 2 x CR2 light side by side using the info at hand. At this point, it will be underdriven as well as this small of light has limited power and heat dissipation available.


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## evan9162 (Sep 4, 2005)

I have some bare luxeon emitters I can run in series, and connect all the slugs to a) a common electrical node, and b) ground - and see what happens. Might take till this afternoon


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## evan9162 (Sep 4, 2005)

Okay,

I've just done an initial test - and I can tell you from it, you should definitely *heed Lumiled's warning about slug isolation*. 

Using 3 bare emitters in series, once the slugs became connected to a common point (even a floating common point), the emitters went dim. 

After lunch, I will start a new thread, complete with diagrams and explanations for this phenomenon.


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## IsaacHayes (Sep 4, 2005)

Evan - sounds great. I always took caution except when hooking them in parallel, but I used AA epoxy even then... I always enjoy tests that clearly prove what is going on!

Harry - Hurry up and make some comparisions and PICS!


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## evan9162 (Sep 4, 2005)

Okay, I posted the definitive luxeon slug isolation thread, titled "Isolation of Luxeon slugs", in the H&M forum.


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## Burnt_Retinas (Sep 5, 2005)

Jumpin' over there. Thanks for being the one to nut this out given the lack of any finer detail data we would all love to have for these.

Chris


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## andrewwynn (Oct 13, 2005)

saaweeet.. i got my K2s.. a plenty.. i was surprised i got enough to make a full prototype of the BAM! and of the MiniMighty.. i even have a couple odd colors including a R/O.. i asked for a blue and got R/O.. the rest are white. 

-awr


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## IsaacHayes (Oct 13, 2005)

wow, you actually go samples. I should of filled that form out too!
Anyone that has samples do these put out more light than current T binned luxIII's??

Andrew: !! man how many did you get!? What did you have to do fill out to qualify?

I'd sure love to get a hand on a cyan!!!


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## HarryN (Oct 13, 2005)

Hi Isaac - Yes, they sure do put out more light than a Lux III. In my very quick and dirty testing with gadget lover on Thurs, we compared it to a TWOK in my proto CR2 light.

The light is resistored, and the board was fully assembled, so we fed it with a constant voltage power supply set to 5.5 V (to simulate the 2 x CR2 setup)

It behaves a lot like a J bin, drawing around 8 % more current that the TWOK, but the Lux readings were 33 % higher. Not quite the 2 X I had hoped for, but I think the "V" bin designation is not measured at the same current that a Lux III is. Not sure if the brightness of a Lux III is measured at 700 or 1000ma.


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## andrewwynn (Oct 13, 2005)

i think that lux3s are binned at 700.. something like 72lum at 700.. 80 at 1000 or something... My insight said that i should 'call' a K2 a UWOJ in my calculations and considering that my K2 samples actually have a hand-written note on them "UWOM".. i was close, just higher Vf.. which is a bit of a bummer.. i need the lower voltage to get full power from my MiniMIghty but since i got Ubin K2s in my sample i can run my BAM! sample higher power and maybe get upwards of 500 lumen out of it!

I think harry got "V" K2s and i got "U"s.. 130lumen at max.. but that is 5.8Wish.. i'll take measurements sometime but have to build the nanos so might be a month. 

-awr


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## evan9162 (Oct 13, 2005)

Hey Andrew,

M Vf, eh? Sounds high. Would you be able to run one for 24 hours to see if the Vf drops? I wonder if that phenomenon will still be present with K2s...


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## Nitroz (Oct 13, 2005)

Good Stuff!


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## HarryN (Oct 13, 2005)

evan9162 said:


> Hey Andrew,
> 
> M Vf, eh? Sounds high. Would you be able to run one for 24 hours to see if the Vf drops? I wonder if that phenomenon will still be present with K2s...




Hi Evan

The U bin Lux IIIs that are on the market are mostly L and M, so for a K2 to run a bit higher is not that surprising. I think we are going to have to be careful how we interpret Vf a bit with Lux III vs Lux V and K2. For my purposes, I was using these devices in a constant voltage (5.5 V) / resistance (2.5 ohm + approx 0.2 Vf protection diode) setup, which gave (approx) 700ma in the Lux III TWOK, and 800ma in the K2. For my purposes, that makes it behave a lot like a "J bin equivalent" in Lux III.

At the actual rated current (I think 1400 ma ?) the Vf will certainly be higher.

BTW, for those interested, the PN of mine are LXK2-PW14-V00.

Also, since the K2 die height is different than my remaining Lux IIIs, it is difficult to exactly compare Lux readings from the same optical system and make clear comparisons.


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## andrewwynn (Oct 13, 2005)

I will post the results of my voltage/current/power. I will be running mine with constant current.. but my max voltage on my boost driver is rated for 16V.. i could swap a capacitor and probably get that up higher though... My UX1L x 4 does run at 15.6V.. 3.9V/emitter at 1100mA.. 

the K2 spec sheet does imply that we can expect about 3.5V at 700mA and about 3.9V at 1500mA.. but with 'M' or 'N' Vf binning that would indicate it will likely be more like 4.2-4.5V Vf... although i did try an N bin UX1N and it ran at a much lower Vf than what i was hoping. 

-awr


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## evan9162 (Oct 13, 2005)

Ya gotta wonder about Vf binning sometimes.

I noticed that the higher binned Lux IIIs actually dropped 0.1-0.2V during the first few minutes of operation! A TY0L I tested dropped over 0.1V in the time it took me to cycle through 5-6 current levels (less than 1 minute). Maybe lumileds misbinned yours? Or perhaps the same kind of drop happened there as well?


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## IsaacHayes (Oct 14, 2005)

ewww M Vf bin. Hight I'd like to see is L. Well, I don't really even use L's.. hehe..
If the efficiency went up then the Vf needs to be down, unless for the added Vf we are seeing a ton more lumens pours out... :thinking: hmmm

The Vf binning is kind of weird sometimes. I've built a lot of TX0K emitter 3D alkaline mods with 1 ohm resistance in them and they have varried on current from 500ma to 1000ma on fresh cells! The TX0K stars in my personal tri-mag all are equal (thank god) in Vf and pull close to an amp each on recharables after a lot of cycles. I'm glad they are all equal as they are ran in parallel so Vf matching is important!

Evan: have you found that the lower Vf (J, H) luxeons still drop their Vf over use? If so is it less of a drop than the higher Vf ones?


A direct comparision of wattage/lumens on say a T binned luxeon with say, K Vf vs a K2 would be interesting. Match the power on both of them say, 3.5watts? throw them in front of a lux meter with no optic, and see what happens. Or throw them in those crude "home made intergrating sphere" and see what happens... Any takers?


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## evan9162 (Oct 14, 2005)

Isaac, 

I saw a loose general trend of higher Vf Luxeons showing more of a drop than lower Vf luxeons, but I only had a few samples of each, so I can't say anything definitive. There was also a loose general trend of higher current causing a larger drop faster, but again, not much sample data.

I think I would need at least 50 samples of each Vf bin to really have a good data set and make any definitive claims either way - right now, the data is rather scattered.


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## HarryN (Oct 14, 2005)

Isaac, don't get too excited or discouraged by higher Vf numbers just yet. The point in general is Lumens per watt - not necessarily Lumens per amp.

Also, there is a bit of a nomenclature change going on, as the K2s such as the 1400 series are being rated at the higher driver currents, not at 700ma like a Lux III. A TWOK looks has a very low Vf at 20 ma - well under 3 v, but rises sharply if you took it up to 1500ma as well.

There are quite a few lights out there that run on 2 x 123 Li primary cells, and use $ 20 circuits to regulate the LED. As the LED Vf rises closer to the Vbat, and if LED efficiencies stay at roughly similar levels (eventually), then the light actually would stay very efficient with more simplistic drive electronics. A good current example is the Lux III Red / Orange on a single primary 123. While a good driver is always beneficial, the voltage sag from a 123 under load, combined with the higher Vf at the higher drive current, and increased ma rating, combine to make this a candidate for an imperfect, but very simple candidate for direct drive.

I am skeptical that there is a good enough CR 123 or R123 that will be able to handle the demands of fully driving a K2 white at 1500ma, even with a high efficiency boost converter. My guess is that internal resistance and cells overheating will be a big issue.


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## evan9162 (Oct 14, 2005)

Harry, 

My understanding from reading the preliminary datasheets of the K2 is that the binning for -14 parts is done at 1A drive current. Thus, an M Vf K2 is roughly the same as an L binned Lux III - a somewhat "high" Vf bin.

BTW - the last version of the leaked K2 datasheet I have my hands on was labled as expiring on 7/21/2005 - does anyone have a more recent version?


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## McGizmo (Oct 14, 2005)

With the understanding that the K2 engineering samples are just that, engineering samples, we can hope that the Vf of production units get down to more manageable levels. I had one sample that I recall had a Vf of 5V for 1500 mA! In one test I did with a K2 that has Vf of 4.6 at 1500 mA in a build using a 1450 mA driver, I got the following:







Now in my opinion, this fellow reached RedLine!!!! :green:

Even the few red K2's I messed with so far have high Vf's as well as the blue. :shrug:


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## evan9162 (Oct 14, 2005)

Wow, what happened at the 35 minute mark? Something with the driver? Catastrophic LED failure?


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## HarryN (Oct 14, 2005)

Thanks for that graph Don. Just a dumb question - It looks like you had approx 6.7 watts going into it, and an air cooled light - no doubt, one of your nifty small ones.

On the Lux IIIs at least, they were recommending 3 sq inches of surface area per watt for cooling - so nearly 21 sq inches of Al. Even if the K2 takes 1/2 that amount, that is around 10 sq inches to keep it under control.

Just curious, would you expect similar behavior from running a Lux V at 800 - 1000ma ?


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## McGizmo (Oct 14, 2005)

I don't know what happened as I wasn't there!  The LED and driver are fine. I suspect that one of the batteries may have called it a day?!?! :shrug: This is my largest light with plenty of mass and I believe > 21 sq." of surface area. The head *is* the heat sink. None the less, I personally think that a 5W demand on a pair of CR123's is at the reasonable limit of power consumption for a LED light and this K2 is asking for more power than is *reasonable*.

Even in a wet run test, it was pretty ugly!!!!!! The Wiz2x2 goes into flicker maddness at a Vin of about 2.5 so did the 2x123 drop to this level during the test or was the starved power what caused the excess ink?!?! :shrug:

There were a couple drops of water in the battery tube and I am guessing that a drop wicked in through the thermacouple's sealed hole and beaded against the thermacouple and inside wall of the battery tube. This would explain the sudden drop in temp seen on the temp graph. Notice that this event was after the system had already gone supernova and the battery chamber temp was already on the wane. 

Unless the K2's efficiency improves drastically over this sample, I think it will take more than a pair of CR123's to drive it full speed. It may be a better idea to use a powerful boost driver on a 18650 Li-Ion? :thinking:






20 minutes of straightline regulation followed by 15 minutes of unstable confusion then followed by a period of moon mode. Hardly a pleasant picture!!!


Now I go up to Ghost Mountain! :wave:


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## modamag (Oct 14, 2005)

Wow, great stuff Don.
Just a stupid question, did you HS the converter?


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## andrewwynn (Oct 14, 2005)

that's a good question.. my drivers shut off if they overheat.. they don't really have any hysteresis built into that circuit so it 'blinks' if it's too hot. wild charts there holy cow 160F i presume that is the temp of the head of the light? i would say you def. hit critical mass on the temp. of the K2. wowza. i just calulated 6.9A on that K2.. even if they achieve the lower Vf they want (listed in the prerelease datasheet) K2s will be 5.8W at full power.. i'm much more interested in the Sbin rated at 700mA... 2.5W for 100Lumen vs 5.8 for 140. 

-awr


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## HarryN (Oct 14, 2005)

I think you are right on track Andrew, a really good place to run the K2 will be in the 700 - 800ma range (maybe 1000 ma on a big light). That is more or less in line with my tests on lux IIIs - run them at ~ 500ma vs rated 700.

I guess for me, this works out well, since 700 - 800ma is perfect for my 2xCR2 light. Of course, unlike Don's test light, it will not be throwing 6000 Lux either.

It is interesting that Don has already proven the need for something greater than 2 x 123s to run these at full power as well. Maybe a 3 x 123 with a buck driver ?


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## andrewwynn (Oct 14, 2005)

yeah know.. when i make a small light lux3.. 500-600 is where i set them if i use pri 123s for sure.. i set them to 830 if using R123s and an ldo driver (that works out to 3.0W.. that rubs me the right way.. a '3W' emitter outputting .. what are you kidding me.. actually 3 W?). 

-awr


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## firstrax (Oct 15, 2005)

evan9162 said:


> Harry,
> 
> My understanding from reading the preliminary datasheets of the K2 is that the binning for -14 parts is done at 1A drive current. Thus, an M Vf K2 is roughly the same as an L binned Lux III - a somewhat "high" Vf bin.
> 
> BTW - the last version of the leaked K2 datasheet I have my hands on was labled as expiring on 7/21/2005 - does anyone have a more recent version?


I have the october version, the data sheet has not changed.


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## mobile1 (Oct 20, 2005)

HarryN said:


> I am skeptical that there is a good enough CR 123 or R123 that will be able to handle the demands of fully driving a K2 white at 1500ma, even with a high efficiency boost converter. My guess is that internal resistance and cells overheating will be a big issue.



My partner is working on an improved version of the GatLight driver - which has an innovative feature which might allow to do just that. The prototype board looks promising however lots of tweaking is needed.... Give it two months, maybe we can all surprise you - it should defenitely allow you to run stuff you can't run with normal drivers....

We'll see....


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## McGizmo (Oct 20, 2005)

The wiz2x2 board is clamped down and sandwiched between the head and contact ring so there is some thermal relief but the IC is not given any great thermal path to the head or body. The thermocouple in these tests was placed against the battery, between it and the battery tube.

Personally at present, I think the strength of the K2 is in its ability to perform in less than ideal thermal conditions and take abuse from either poor thermal relief or in cases of high ambient conditions. Driving it at max seems to have very marginal returns and I too am most interested in the high flux LED's rated at the lower current. I suspect that there will be equal achievers in the higher current part numbers but their color binning will be off in underdriven states.

I want more power potential so I can get where I want with less foot on the throttle. Cost aside, driving a Luxeon at 30 mA beats the heck out of driving a 5 mm at 30 mA in terms of efficacy.

I am a bit surprised at the high Vf of the K2 and it seems to be more in line with the Cree and Nichia dies. If you look at the pic below with both blue LED's, you can see that the K2 has a different die structure and I wonder if this is evidenced in the seemingly higher Vf's?!? :thinking:


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## McGizmo (Oct 20, 2005)

Mobile1,
It will be interesting to see what you come up with! Wayne's NexGenx2 is pretty efficient and capable of high current, both in and out. Mated to a single CR123, in a run test I did, there is no real indication of constant current but what appears to be the power curve of the CR123 at its capacity?!?! This is a runtime on a UX1J which is a very efficient Luxeon to start with and in comparison to current K2's, it will provide superior flux levels over the K2 at significantly lower power requirements.


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## Billson (Oct 20, 2005)

mobile1 said:


> My partner is working on an improved version of the GatLight driver - which has an innovative feature which might allow to do just that. The prototype board looks promising however lots of tweaking is needed.... Give it two months, maybe we can all surprise you - it should defenitely allow you to run stuff you can't run with normal drivers....
> 
> We'll see....



Even with extremely efficient drivers, the question still remains whether a single CR123 can provide the current requirements of the K2 when driven at full power for any usable period of time.


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## HarryN (Oct 20, 2005)

The challenge of driving a K2 at full power (1500ma) is not the electronics (which our enlightened EE friends can certainly do), it is the 123 cells themselves. 1500ma out of the driver at something like 4.5 - 5 V will require something like 7 - 8 watts in. 

Using the plots by Silverfox at 2 amp draws, they barely maintain 2.5 V, so marginally 5 watts. Perhaps we can convince Tom to run a few cells at an 8 watt draw rate and see what happens, but his comments in the thread indicate the potential of thermal runaway from 1 cell.

Frankly, this is probably not that important - as 8 watts of LED heat plus the internal resistance heat of the cell would force a short run time in a small light anyway - I probably could not hold it for more than 30 seconds.

I am starting to get a handle on how to optically deal with the K2 die height, which is useful. It is not so straight forward to work with optics like this for some applications.


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## SemiMan (Oct 20, 2005)

I have a sample K2 running about 3.8V at 1.5Amps or less than 6 watts. It runs about 3.5V at 750mA. I see a huge increase in light between those two settings by the way. I am using a reasonable heat sink for my tests. Something a that would make for a large flashlight heat, but not unusable. Boy does it put out a ton of light when you run it at 1.5A though!

In terms of efficiency, I can probably hit 90% efficiency with a driver as long as I am over 5V on the batteries. Getting that efficiency with a modern synchronous dc\dc is not too tough with a good controller/fets.

I would be curious to hear more about what people are achieving with optics on the K2 though. Some optics for the L1/L3 seem to give reasonable results with the K2 (reflectors), though the TIR lenses are a bit off.

Semi-Man


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## andrewwynn (Oct 21, 2005)

SM.. do you know which model K2 you have? that is right in-line with the specs of the datasheet ([email protected] [email protected]).. I will be getting some K2s into some IMS20s and McR20 reflectors soon.. results will be posted. 

I've only lit up a couple K2s briefly .. DD from an AAA LiON and constant current a different time at 1000mA (amber model).. in both cases 'dazzling' applies. I'm dying to get a 4-up 'BAM-K2' going to compare with the 4x UX1L i have now. 

-awr


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## evan9162 (Oct 21, 2005)

From Don's picture, it looks like the K2 uses a different current spreading technology than the classic Luxeon - the current way uses parallel bars to ensure even current spread across the area of the junction - the only structure I see in the K2 are a set of dots - perhaps they are a vertical contact that still spreads the current evenly?

Don, what kind of image do you get if you focus the beam with a lens or acrylic sphere? Doing so on a classic Luxeon results in a projection of the die, complete with the "grille pattern" due to the current spread contact pattern blocking light emission - is there a similar pattern for the K2?


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## McGizmo (Oct 21, 2005)

Evan,
A focused projection with an acrylic ball gives you a very clean square of light. There is just a hint of nulls where the holes are but you really have to look for it. I was told by a Future rep that the holes are for thermal relief. :shrug:


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## andrewwynn (Oct 21, 2005)

now i'm really getting excited to get my K2s running.. so sad to have like 10 K2s and not having the time to put them into something. aargh. off to make the nanos finally.

-awr


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## mobile1 (Oct 21, 2005)

Are those ten all white ones? We only got 4 white K2's.


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## andrewwynn (Oct 22, 2005)

8 white a couple color ones. i had specifically requested 'at least 7' so i could make 1 full prototype of BAM and of MiniMighty.. i was pretty surprised when futurelids came through but quite happy about that. 

-awr


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## pete102 (Oct 22, 2005)

Having read and downloaded the spec sheets on the new K2 could someone please tell me if these are available to the public and if so where can they be obtained. (UK if possible)
I am currently building a dive torch that uses 7 Lux III LED's and would like to possibly replace these with the K2 models.


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## mobile1 (Oct 22, 2005)

The latest I have heard they won't be available before April. And we got some samples because we (or at least I) got through some interview process - where they decide whether they wanna give you some. Ours however came unmarked without any bin codes... so we'll see.


*Don -* regarding driver - it's my partner who is doing it (I don't know jack????  ) about drivers. However our driver is regulated (my personal preference). What I understand is that they found a way to regulate without wasting (too much) energy. They are patenting the thing at the moment.

So as soon as we have a couple of prototype boards ready, I would love to send out a board to someone who can test it and compare it to existing drivers - just to get an independent test of whether this thing really does what we think it does. The board will probably come as a Luxeon Sandwich combo. What do you think who would be the best person to send a sample board to, in order to run some comparison tests, YOU? :thinking: Let me know. Time frame until everything is finalized is about 2 months.


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## McGizmo (Oct 22, 2005)

Mobile1,
I would be happy to stick one of your drivers on the bench and take it through some paces. I have some doubts if as I understand it, we already are seeing some drivers working in the 90% efficiency ranges. An additional 10% will just not amount to much in terms of gains from the CR123, IMHO. At this point, significant gains will be due to increased efficacy in the LED, itself, I believe. The few K2's I have messed with all had high relative Vf's and due to this, they needed to have greater flux at specific current levels comparied to the LuxIII's just to reach parity, let alone step out ahead. To date, the only advantage of the K2 I have seen is that of lumen maintenance under adverse thermal conditions; either self induced by drive levels or as a result of poor thermal relief or less than optimal ambient conditions. 

On the K2 front in specific and the current Luxeon offerings in general, I have heard rumors as well as experienced some issues which leave me less than optimistic about Lumiled's future or Future's Lumiled's for that matter! :nana:

If I thought it would make a difference, I would start a thread in C&J regarding the state of Luxeons. :green: I truely look forward to the day we have viable options and can place our "votes" elsewhere out of spite if nothing else!! We all have a debt of grattitude owed to Lumileds for providing us the Luxeons when there has been nothing else available and they indeed have charted new territory for us. Likely we have paid this debt and it may be we have paid more than we should have had Lumileds been more forth coming and less exploitive of the situation. :shrug:

I will try not to bite the hand that feeds me but I do have my eyes out for another hand to go to!  April is a ways away and who knows what tomorrow will bring.


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## andrewwynn (Oct 23, 2005)

I agree for the most part about the K2 and when they help.. with Vf in the 4V range like Don said, they are at parity with Lux3s when the same WATTAGE is applied in many cases.. I will have a BAM-K2 operational soon and will also have a BAM-Tbin running soon so i will have some direct comparisons between Tbin Lux3, Ubin Lux and K2 lux3 using 4-up in a single head. 

Somebody just mentioned above getting their grubs on some low Vf K2s.. mine alas are not.. they are M and N but they are binned 'W0'. so at least i can compare directly to some TWOJs i have around.. i will work on running them the same CURRENT and test that.. and the same WATTAGE and test that for output. 

-awr


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## SemiMan (Oct 26, 2005)

I have not had a chance to put my K2 samples through proper optic tests yet, but to use a technical term, they are "stinking" bright when I run them hard. I seem to have "good" parts. I would not say they are a lot brighter at 350mA then LuxIII, but when you run them at 1A, and higher, they seem to put out a lot more light than T bin LuxIII.

Semiman


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## goldserve (Oct 27, 2005)

I have K2 parts too but i believe the voltage is too high. I need a good driver that will drive these parts.


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## HarryN (Oct 27, 2005)

SemiMan said:


> I have not had a chance to put my K2 samples through proper optic tests yet, but to use a technical term, they are "stinking" bright when I run them hard. I seem to have "good" parts. I would not say they are a lot brighter at 350mA then LuxIII, but when you run them at 1A, and higher, they seem to put out a lot more light than T bin LuxIII.
> 
> Semiman



Yes, the ones I have are clearly brighter, almost pain level at 700ma. I can still stand to look at a TWOK at 700ma, but not the K2.


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## Opto-King (Oct 28, 2005)

Hi everyone,

Thanks for charing your test results and thougths!
I must ask if someone have been testing Power LED's (1W, 2.5W or 5W) from Seoul Semiconductors. And if so; how was the result?
Thanks!


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## HarryN (Oct 28, 2005)

Opto-King said:


> Hi everyone,
> 
> Thanks for charing your test results and thougths!
> I must ask if someone have been testing Power LED's (1W, 2.5W or 5W) from Seoul Semiconductors. And if so; how was the result?
> Thanks!



That might be a good question for its own thread. Perhaps you would like to start a post on that to keep the info straight ?


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## andrewwynn (Nov 1, 2005)

HarryN said:


> Yes, the ones I have are clearly brighter, almost pain level at 700ma. I can still stand to look at a TWOK at 700ma, but not the K2.



miliamps smiliamps.. how about WATT comparisons... 700mA at 4.1V = 2.9W.. (expected K2 reading in the early batches)... 700mA at 3.3V = 2.3W.. with 24% more power i'd hope they are brighter.. but those are just random numbers, so i'm quite curious about the comparative lumen/W figures. 

-awr


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## HarryN (Nov 1, 2005)

Hi Andrew

All I can tell you is that using the same setup (batteries and resistors) that gave me 700ma in a TWOK produced 800ma in the K2s I have. That is not exactly science, but it is a pretty good indication that the Vf was lower than "K". (at 700ma) Backing the K2 down to 700ma, it was "painfully" brighter than the TWOK at 700ma.

BTW, the identical setup using the latest Cree 3 watt Xlamp (which is a VERY nice part BTW) produced something like 550 ish ma drive currents


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## evan9162 (Nov 1, 2005)

Would you prefer to answer here or via email?


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## HarryN (Nov 1, 2005)

Maybe Ron will be kind enough to start a Cree Xlamp thread. That would be a wonderful resource.


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## SemiMan (Nov 1, 2005)

Ron, Cree states in your documentation that you have 50,000 hour life at "recommended" operating paremeters. However, you also state that at a 94C die temperature in a thermal example that the LED life will be reduced, though your maximum die temperature is much higher.

Can you tell me what die temperature for you white product that you will support that 50,000 hour, 70% of initial brightness specification?

Semiman


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## McGizmo (Nov 1, 2005)

Semiman and Ron,
Please, for all of us interested, can we start a new thread on Cree LED's so this info is not lost in a thread based on another topic?  I too would like some insight into the Cree LED's!!! :thumbsup:


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## SemiMan (Nov 1, 2005)

Works for me!


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## IsaacHayes (Nov 4, 2005)

Just getting back into this thread. Don - very interesting the shape of the die. The grill on the luxIII is to disperse the current evenly over the die IIRC. The K2 doesn't have this but has dots. I'm wondering if those dots aren't for thermal releif, but for current distrubution (or both). Perhaps surface of the "grill" to the die relates to Vf? On the other hand it seems more light would be exposed from the die, and a direct image would be cleaner.. 

But alas the higher Vf resulting in higher wattage negates any gains in lumens in power/watt compared to most luxIII's it seems... I only hope these "samples" people have right now are early prototype stock and that when they go to release they have much since then perfected them to typical luxIII Vf area levels...


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## 3rd_shift (Nov 4, 2005)

Can someone email me a copy of the form needed to fill out to get a few of these?
Or a link to get the form will work too.
I am wanting to try these in a miniquad.
Pictures and beamshots WILL BE COMING! as soon as I have the leds. :rock:


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## andrewwynn (Nov 7, 2005)

Got to do some 'first tests' with my K2 samples. 

First off.. they are very neat emittesrs.. but they are the -14 models that don't have substantially more lumen/watt than the lux 3s.. in-fact they were binned "UW0M" and "UW0N"... pretty high Vf.. so... though they were ranked "U" for brightness.. that is at 1000 mA not 700.. so the reality is they had about the same exact output as the Tbin emitters i have in stock (TW0J). 

The built quality and fit n finish is awesome.. i really like the new domes they are so clear that you can't even see them straight on... though from a sharp angle you can actually see a tinge of blue and hazyness... 

For people that missed it or didn't know this... the lux 3 emitter dome is hard acrylic shell filled with silycone.. the K2 emitter, the dome is a hard molded silicone.. not as hard as the acrylic. 

A couple other things 'of note'... 

1) with almost unimaginable odds.. the 'nc' leads.. really are not connected unlike the Lux3 which they are.. 

2) reverse powering... fortunately.. at a reasonable applied voltage the 'diode' part of LED does its job and nothing bad happens. 

3) heat... they do in-fact deal with a LOT more heat than lux3.. i accidentally heated up one a lot hotter than a lux 3 would have survived and it's still ticking... i did notice that the output was starting to dim from the heat before i realized just how hard i was driving the emitter.. whoa! 

They are 'the way of the future'.. the fact they can be smt soldered directly to PCBs will make them 'the emitter' of choice for mass assembly.. and i believe that the price of the K2s will be very reasonable almost from the get-go.... maybe a 'gut feeling' i have. 

I still have my fingers crossed for that Sbin model.. i have a feeling that will be the new 'Ubin' and i suspsect those will sell at a premium price for sure. 

I hope to have a prototype BAM running soon from the K2s.. but the Vf is too high i'll have to swap out the capacitor at least on the driver board before i can output enough voltage (like 17+) to run them full power, or even at 1A.. 

So.. the summary so far.. output doesn't blow me away compared to lux3s.. but the design is quite superior.. so just have fingers crossed they can pull off the estimated 3.5Vf they have for the Sbin models. 

-awr


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## mobile1 (Nov 22, 2005)

Here some results comparison of a K2 @1000mA (left) and a Lux III @1000mA both in a GatLight.
This is what the result looks like.
LuxIII at 1000mA got 235 lux at 10inch
K2 at 1000mA got 315 lux at 10 inch
The K2 looked quite a bit brighter - and the light gets quite a bit less warm (so all good news). Here are some beamshots - unfortunately the K2's we got are pretty yellow (compared to the nice LuxIII we got)

This first shot, how the K2 (left) and LuxIII (right) compare in real color






Then here converted to black/white to better see the difference





Everyone with a GatLight can send in their driver - once the K2 becomes available, to do an upgrade.


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## IsaacHayes (Nov 22, 2005)

The hotspot looks less bright and larger on the K2. I bet this is because the die postion is different. But the light meter says it's brighter?

If you could get it to focus as tight as the luxIII, I bet it would really be a whole lot brighter.

Can you confirm that the K2's have a different die hieght compared to luxIII's? What about compared to the new round slug luxeons... is it the same?


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## Sengoku (Nov 22, 2005)

I can confirm that the die is lower compared to lux3s and the new joker lux3s with the round slug. heres a photo:





Photo from http://forum.flashlight-fan.com/cbbs.cgi


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## nemul (Nov 22, 2005)

someone please feel free to send me a K2 sample!


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## IsaacHayes (Nov 22, 2005)

Sengoku: Wow, that's really low!!! I wish Lumileds would pick a die height and stick with it. Now we have 2 adjustments to make on optics/reflectors now...

Also note the bond wires are flat compared to round loops. I wonder if they would be more of a shadow with the die since they are parallel kind of with it now..


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## mobile1 (Nov 22, 2005)

IsaacHayes said:


> The hotspot looks less bright and larger on the K2. I bet this is because the die postion is different. But the light meter says it's brighter?
> 
> If you could get it to focus as tight as the luxIII, I bet it would really be a whole lot brighter.
> 
> Can you confirm that the K2's have a different die hieght compared to luxIII's? What about compared to the new round slug luxeons... is it the same?



Yep light meter says its about a third brighter, I am sure the wider beam is due to the lower die - I guess filing down the optics a little bit would take care of that. - Have to test that.

Hmm I guess that makes the GatLight the first K2 (1000mA) light - or has anyone else put one of those into a light already.


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## chimo (Nov 22, 2005)

The dome on the K2 also seems to be a lot clearer. Is it just due to being less dirty/newer? 

I wonder there is a difference in Index of Refraction for the different dome materials that could contribute to a change in the optical properties as well.

Paul


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## IsaacHayes (Nov 22, 2005)

mobile1: There was a KIT (don't even ask me to spill that out!) sold with a k2 in it a bit ago. I think there was another light too someone had with a k2 in it. If you file down the optics and get it to focus as tight as the LuxIII, you will have HUGE difference in brightness I'm sure.

chimo: the k2 has a soft rubbery dome, and I bet it looks clearer because it's not as shiny sort of AR/Anti-glare to it. You can see that by the photo too btw, less reflections.


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## HarryN (Nov 22, 2005)

Hi - I have a K2 in one of my 2 x CR2 light protos. Definitely brighter, and the newer top style makes for a smoother beam.

I measured an increase in Lux of 25 + % over a TWOK, but that was with an optical setup for the older Lux III focal point.

I suspected that the Lux III was evolving toward the K2 technology, and that die height picture seems to indicate this as well.


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## NewBie (Dec 3, 2005)

*Re: K2 Emitter*



NewBie said:


> > *idleprocess said:*
> > Summary of my LEDDB entries on the K2:
> >
> >
> ...



I'm looking at your chart, and the T bin Vf on the K2 seen so far averages 4.051V at 1000mA (4.051W) and a Vf of 4.27 at 1500mA (6.405 W). This drops the lm/w to 19.75 when at 1A and 18.74 lm/w at 1500mA.

*So, the K2 at 1000mA:*
Then you'd have about another 10% loss for the die temp to ambient:
4W * 9 C/W, 36C die, plus another slug to ambient through the flashlight body rise of 20C, so you'd be looking at about 56C rise at the die (for the 1000mA K2), so ambient of 25C + 56C puts you at 71C, which equates to 10% loss in light output.
Thus the K2 in practical application at 4W, would be *17.78 lm/W, for 71 lumens total.*

*So, the K2 at 1500mA:*
Then you'd have about another 16% loss for the die temp to ambient:
6.405W * 9 C/W, so 57.7C die temp, plus another slug to ambient through the flashlight body rise of 30C, so you'd be looking at about 87.7C rise at the die (for the 1500mA K2), so ambient of 25C + 87.7C puts you at 112.7C at the die, which equates to 16% loss in light output.
Thus the K2 in practical application at 6.405W, would be 15.7 lm/W, for *100.6 lumens total.*

Blasting high power through the die is not a really the holy grail. In fact it is far from it. The better approach is to raise the efficiency extracting light from die, so that you don't generate the heat in the first place. This alone takes you very far, pretty quickly.

I'd certainly have to agree with others, that the K2 PW12, or under powering the PW14 version of the K2, looks very attractive though.

The 70lm/W CREE device should be out soon. 500mA should put it over 100 lumens (including die heating losses), with only 33% of the power consumption for K2 part.


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## HarryN (Dec 3, 2005)

One of the interesting things about working with the K2 / Lux III's has done for me, is had me take another look at the Lux V. There are some WWOS emitters starting to become more available, and (I know Newbie will cringe at this) can be burned to drop the Vf and run in and DD with 2 x CR123s to around 250ma - a very efficient setup.

I have demonstrated that this works on a bench. It won't win regulated prize of the year, but it is a remarkably easy and simple setup for flood apps.


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## NewBie (Dec 5, 2005)

Looks like the LumiLEDs Luxeon K2 has that bad Vf shift problem like their old parts.

Here you go Harrry:


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## nemul (Dec 5, 2005)

still waiting on my sample! hehehe


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## HarryN (Dec 6, 2005)

Interesting Vf curve Newbie. Not sure if I would call LEDs getting better with age a "problem" or not, since the pro's all current drive anyway.

What I found interesting, is that you could use a Li Ion cell in DD and still stay in spec, even after the Vf settles in. (not that I recommend that or anything, but it is interesting.


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## LITEmania (Dec 6, 2005)

Newbie :

If I run K2 around 500~700mA (for my poroject - non flashlight), 
MCPCB will not be neccesary ?

LML clams that K2 needs not any heatsink.......???


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## NewBie (Dec 6, 2005)

LITEmania said:


> Newbie :
> 
> If I run K2 around 500~700mA (for my poroject - non flashlight),
> MCPCB will not be neccesary ?
> ...



You'd still be making 1 to 2 Watts of heat.

Humm, I'd still definitely suggest a good heatsink path from the emitter to the surrounding environment.

Otherwise, you could suffer a 35% reduction in lumens from the get go.

If it is the red/orange/amber part, you could be looking at loosing 90% of the light output.

If you think about it, there is usually some way you can do something to help get rid of the heat. It doesn't have to be a MCPCB. I'd definitely hook a thermistor or something up to the slug to make sure it isn't getting too hot in the assembled product. It is a good idea to do so, in any design, there are some pretty big and respected companies that have been surprised when LumiLEDs pointed out it was the companies design that was killing the Luxeons due to heat.

We won't go into one company that didn't bother with the current regulation in an outdoor product...or another that decided to hook them up in a parallel arrangement and wondered why some of them barely lit up and others really bright, and how they were loosing parts in the field...


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## andrewwynn (Dec 6, 2005)

the 'non sink' solution implies stuck on an open PCB w/o being encapsulated... they can run hotter and have 1/2 the loss from heat so there are surely some solutions where no extra special care to sinking is incorporated. 

-awr


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## HarryN (Dec 6, 2005)

I would at least try to get some heat spread around on the surface of the board - maybe 3 oz copper, but ultimately, you need to get the heat out of the "system".


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## NewBie (Dec 7, 2005)

andrewwynn said:


> the 'non sink' solution implies stuck on an open PCB w/o being encapsulated... they can run hotter and have 1/2 the loss from heat so there are surely some solutions where no extra special care to sinking is incorporated.
> 
> -awr




Andrew...hello?

It doesn't have half the losses due to heat.

Lets take the part with no heatsinking and equal power between the two devices. Thus, with no heatsinking, at the same power, both die will attain the same temperature. 

Lets say the die reached 100 degrees C. At 100 degrees C die temperature, the Luxeon III light output would be down to 78.15%. This would be a drop of 21.85%.

Lets say the die reached 100 degrees C. At 100 degrees C die temperature, the Luxeon K2 light output would be down to 84.28%. This would be a drop of 15.72%.

The light output loss at equal die temperatures is only 28.05% lower with the Lux III, not 50% as you stated.







Where the K2 really helps alot is when you heatsink it robustly.

The K2 has a thermal resistance of only 9 C/W junction to case (die to slug).

The Luxeon III has a thermal resistance of 13 C/W junction to case (die to slug).

The K2 has a 30.77% lower thermal resistance. 


Now, assuming was have a nice low slug to ambient, such as a hotlips heatsink and say a 4D Maglight, and you properly bonded/soldered the K2 to the heatsink, we'd be looking at a rise in die temperature that is very roughly 30% lower. Assuming ambient is 25C, and with the Lux III we had 100 C die temp, the difference is 75 degrees C. Since we have 30% lower thermal resistance the die temperature rise would only be 52.5 Degrees C. 25C + 52.5 Degrees C = 77.5 Degrees C die temperature. This would give you a gain in light output of 4.84%.


Now we take the the 15.72% gain in light at any given die temperature from up above, and add the 4.84% from lower die temperatures due to lower thermal resistance, you are looking at roughly 20.56% more output overall. 

If someone was foolish enough to have no heatsinking, you are not going to be able to run the K2 at the full 1.5A they advertise, with out some very seriously adverse issues, and the light output would be **** poor. You'd also have to find better solder, as regular tin/lead would melt.

As I recall, their demo with no heatsinking, had the emitter soldered on a regular FR-4 PCB, which does act as a heatsink, and had to be ran in open air. Yes it is poor, but much better than no heatsinking at all. Though, I did notice they did not run the part at the full 1.5 Amps...

Ah, here it is:
"For example, New LUXEON can be mounted on an FR4 printed-circuit board (PCB) and driven at 400mA, in an ambient environment up to 40°C without a heat sink. This approach works for a wide range of applications such as undercabinet lighting, task lamps etc. With the New LUXEON, costs will be lowered and solution engineering simplified."
http://www.lumileds.com/newsandevents/releases/PR34.pdf

So folks, please don't be ignorant and put 1.5 Amps through your K2 parts when they come out and not heatsink them. 

If you solder them down on a large piece of FR-4, with a copper area on it that you solder the slug to, and the board is in open air, please keep the current below 400mA.


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## IsaacHayes (Dec 7, 2005)

I think they said that you could run 350ma with no heatsink bare star, or was it 350ma with emitter on normal pcb? Something along those lines. Just becaues you can, doesn't mean I want to...

I bet a K2 on a copper O-sink would really have some nice output at high current compared to LuxIII's.


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## mpf (Dec 7, 2005)

IsaacHayes said:


> ...
> I bet a K2 on a copper O-sink would really have some nice output at high current compared to LuxIII's.



Copper v Aluminium is not an improvement in steady state. You still need to get the heat out of the metal into the air (or hand or ??).

What we need is good heat transfer to a 'big' heat sink. The size of big depends on how long the batteries will last. 

In another thread I suggest a dummy battery filled with 'cold pack' liquid.

But I am open to alterative suggestions. In my case I need to dump about 17W for 60min. I don't have the strength to carry around that much copper. :-(
matthew


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## NewBie (Dec 7, 2005)

mpf said:


> Copper v Aluminium is not an improvement in steady state. You still need to get the heat out of the metal into the air (or hand or ??).
> 
> What we need is good heat transfer to a 'big' heat sink. The size of big depends on how long the batteries will last.
> 
> ...




If you don't need a waterproof setup, you could add a miniature fan. Sunon used to make a 6mm by 6mm, but I don't see it on their site (which doesn't mean it doesn't exist).

But they do have their more common 17mm by 17mm by 8mm fan that moves 0.9 cubic feet of air per minute. And a 25mm that moves 3.1 cfm.


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## mpf (Dec 7, 2005)

NewBie said:


> If you don't need a waterproof setup, you could add a miniature fan. Sunon used to make a 6mm by 6mm, but I don't see it on their site (which doesn't mean it doesn't exist).
> 
> But they do have their more common 17mm by 17mm by 8mm fan that moves 0.9 cubic feet of air per minute. And a 25mm that moves 3.1 cfm.



Thanks for that, I started looking at fans and was put off by the prices I saw.
Have you seen any pricing on these? I don't need waterproof, just rain proof.

At the moment I am thinking of a box without a bottom or lid and the heat sinks all facing inward so you dont scratch yourself. The air flow is then in the bottom out the top and the leds mounted on the front face. 

The handle is a tube across the to of the box.

matthew
p.s. sorry getting off thread here.


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## mobile1 (Dec 9, 2005)

Well regarding fans.... sometime ago I did a small Downboy powered 3x w-bin 5W mod powered by 8AA batteries that would fit into the palm of your hands. The heat this thing created was pretty insane, so I put a cpu fan with a heatsink underneath the LEDs (It was I think a 50mm fan - however the thing still got hot...
So I don't think such a small fan would make much of a difference other then that it's pretty cool.... to have spinning part in there...


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## Rommul (Dec 10, 2005)

All this talk about fans is pretty unrealistic unless there is substanstial surface area for the fan to blow over.

In other words if you want the fan to be effective the area being cooled will need to be finned in order to efficiently transfer the heat to the air (lets not even get into the issue of exhausting warm air and bringing in fresh air into a water resistant setup like a flashlight.)


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## gessner17 (Dec 13, 2005)

If I was able to get a K2 with a reasonable VF, any idea how these would work in something like a LC or LH? How would they react to PWM???


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## goldserve (Dec 13, 2005)

I really dislike the soft dome around the die. You can like press on it and deform the light coming out. Dirt seems to stick on it more.

Also, have you noiced the beams are not perfect? The hotspot has some hazy effects to it.


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## IsaacHayes (Dec 13, 2005)

goldserve: That's what I was afraid of. Dust sticking to it. Whats the hazzy artifacts you speak of? What reflector/etc are you using? Pics?


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## Sengoku (Dec 13, 2005)

Thats to do with the die position, you need to mod the reflector/optic in order to get a perfect beam.


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## goldserve (Dec 13, 2005)

I've seen it in a few reflectors...mcr-20, jil DD.

I can see the dome warp sometimes...maybe i've broken some bond with the die and now there are gaps? If that's the case, that sucks! 

Sorry, I can't seem to capture good enough beam shots.


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## HarryN (Dec 19, 2005)

I was playing around with a proto of my CR2 side x side with a K2 V bin tonight. The light has 3 levels (approx 25 / 250 / 750ma) so it is quite underdriven from the 1500ma spec. 

I originally was a little disappointed that the beam color seemed a tad yellow, but I assume it was an X1 type tint, and I am underdriving it a lot. I was grilling some steaks outside in the rain tonight, and noticed a couple of interesting things - as usual, the ability to discern red / cooked meet was not as good as an incan, but this one was enough better that I didn't believe what I was seeing, and overcooked the meat (ok, I do that pretty often, but usually, it is related to my cooking skills, not doubting the light) The second is the ability to see purple flowers - very well. The green leaf colors, etc, were definitely better than I remember on my other Lux IIIs.

At 750ma, even with the very small reflector (12mm) I am using, it puts out about 500 Lux, and I can see all over my yard, even at the 250ma. At full power, I can easily identify anything at 20 meters very well.


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## NewBie (Feb 3, 2006)

I was looking at the Future Electronics (the North American Luxeon distributor), and happened to notice their K2 pricing was lower than a Luxeon III.

Go figure...


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## Billson (Feb 3, 2006)

Maybe it's an introductory price?


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## andrewwynn (Feb 3, 2006)

It was expected from the beginning to be a lower price. I have a feeling that is because of the nature of the binning and the production styles.. I haddn't mentioned that from the beginning i'd expected the K2 to be cheaper, but consider the way they will be used.. in some cases by the 100,000s or the millions.. when step up to having a wave-solderable machine placeable part... it opens up some VERY big doors of opportunity for mass production which will bring the price way down. 

Kinda cool.. i had figured that LL would juice the customer 'because they could' and it's very nice to see they aren't going to it seems.

-awr


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## BentHeadTX (Feb 3, 2006)

Andrew,
The K2 is cheaper than the 1/2 price LuxeonIII?!! Woohoo! This would work well for the BAM! project. Hopefully, very low voltage-high output K2 bins won't cost over $10 higher per piece than "normal" K2 bins. May a SWAH or SX1H spool of a 1000 K2's roll your way.


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## HarryN (Feb 3, 2006)

What I am seeing is that both the K2 U brightness 14 series and unbinned Lux III are the same price - about $ 3.50/ each. The bottom line will be - how important are the rest of the binning numbers ? You still cannot really buy a premium binned Lux III for less than 3 - 4 x that.


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## andrewwynn (Feb 4, 2006)

The BAM and MM projects were BOTH re-directed toward using K2s for exactly the reason that i was anticipating a price on the order of $6-7 in quantity.. and if looks like that might be an over estimate. it will bode VERY well for both of those projects considering they both use like 3 emitters per unit.. One thing that is really nice with mult-emtters as well is that minor differences in color bin meld into one color. 

I will be aiming to pick up exacly like you mention.. a spool of 1000 Sbins very soon.

-awr


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## BentHeadTX (Feb 4, 2006)

Save some of those S__H bins for my BAM! order!


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## andrewwynn (Feb 4, 2006)

I have 60 K2s on order for the first 15-20 BAMs.. they will likely be higher power U-bin K2s.. brighter but at the cost of runtime and voltage limitations might possibliy limit to 3 emitters, but my test bench uses L bin L3s.. so 4 of them are almost 16V so i think we'll be good. They will be VERY VERY bright that can be rest assured.

-awr


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## Nitroz (Feb 6, 2006)

THis is great information, can't wait for the k2s!


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## trivergata (Feb 7, 2006)

any word yet on how tough this will be to get a good beam out of a McR27 with the new die height?

Josh


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## sonnebln (Feb 14, 2006)

Isn't the Cree better in terms of efficiency? (highest order bin: 57-67lm @1W)
And could be run directly with LiIon without driver or resistor (which would drop efficiency) - see https://www.candlepowerforums.com/threads/100228

And shouldn't cost more than a K2, see here:
https://www.candlepowerforums.com/threads/105667


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## LITEmania (Feb 15, 2006)




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## goldserve (Feb 15, 2006)

That's a really tight hotspot! What a difference!


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## Doug S (Feb 15, 2006)

Has anyone seen a diagram or have first hand experience on what a crossection of the slug and plastic housing looks like? On the old luxes it was pretty easy to inadvertantly push the plastic off of the slug. In the new gen Lux IIIs the slug is stepped to firmly lock the plastic to slug. There is a good diagram in the McGizmo Lux III Generation Issues thread 
https://www.candlepowerforums.com/posts/1115213&postcount=3


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