Luxeon Q, observations and testing

Interesting thread .

I'm not in for the hidden giveaway because I have lots of emitters

nice testing :slight_smile: I could use another interesting led so please count me in!

Cool test and I dig the 3D Photos! Those are fun to look at, how do you make them? I am out of the giveaway. No reflow skills here. If oldlumens doesn’t enter you can give my entry to him if you want.

Thank’s for the test, djozz. I would very much like to try one of theese. I have bare boards for xpg types.
(PM sent)

djozz. You have seriously got me worried about what you are doing. For this I thank you. Very nice work indeed. Happy xmas. :beer:

Thanks everyone for the nice comments. I really like this exploring unusual emitters, I never know what comes out because the way every different factory make the leds are pretty different and the factory specs are so conservative and what we do here is way over specs. Of course I want a new emitter to perform better than the ones we are used to, but apparently the Cree leds are pretty hard to beat. I have a Luxeon Z that I will try to test sometime (1x1mm, no dome), but first I must find a way to mount it, the footprint does not fit any of the for me available copper boards and it is soooooooo tiny.

@RaceR : you are right, the xp-g2 and xp-e2 come at 70CRI minimum, also at cool temperatures, while I thought that was 65CRI, I should have checked that. So the LuxeonQ is not special CRI-wise. I corrected the OP.

@comfy: removing the phosfor at the sides of the die will produce a narrower beam, but the illuminance of the die (and thus throw) I expect not to increase. If you remove the surrounding phosfor straight up to the die there will be blue light leaking from the sides (should be cool looking in a reflector light :-) )

Xp-g2 and xp-e2 are 70CRI typical,Luxeon Q is 70CRI minimum,slight difference.

Your lumen results for xp-e2 are close to datasheet,but for luxeon Q they are too low(it should be around 300lm@1A).Maybe wider emitting agle causes more light hits reflector-more loss?You should send one to texaspyro,Int. shpere will be more precise.

Just a note, luxeon Q is totaly different technology from Luxeon Z,Z ES,TX etc. Vf and thermal resistance are worse.Vf is higher because chip is much thicker-longer vias,similar to cree sic chip.So this isn't true TFFC anymore.Thermal resistance is worse because supstrate is ordinary alumina,Luxeon Z(ES),TX,M are mounted on Aluminum nitride supstrate(thermal conducitivity is sky high compared to alumina).

And one more thing:I noticed your "death" current for Xp-g2 and Xm-L2 is much higher than what other people measured.
I killed two xp-g2 somewhere between 5 and 5.5A,others also reported 5.2-5.3Amp.Which multimeter do you measure current with?

My lumens are not bare led lumens but 'out-of-reflector' lumens, with the LuxeonQ at 1A I measure 245 lumens, the datasheet states 305, so I measure 20% less which could be typical for the light loss from a reflector. The XP-E2 R3 at 1A is 266 lumens minimum according datasheet, 20% reflector loss leaves 212 lumens, but I measure 240 lumens which seems higher than the datasheet. But my set-up with the led on copper and the board on a block of aluminium cools very well, so at 1A I expect the junction temperature to be closer to room temperature than to 85degC at which temperature the datasheet numbers were obtained. But then, the LuxeonQ should be cooled just as well, but still performs close to what the datasheet tells at 85degC, perhaps the wider emitting angle does indeed spoil the output more than the XP-E2... Well, I don't know, this is what I see with my limited equipment, And ok, I will send one to texaspyro so he can do some proper measuring on it.

I have hoped for some time for someone more accurate than me and with better equipment to stand up and do this led-stuff for BLF, even though I enjoy this playing around with leds very much. Nevertheless, I still presume that my -admittedly makeshift- set-up only suffers from relatively small inaccuracies that influence the numbers with say less than 5% . But I do not rule out that something is more off, that is why I always describe how the measurements are done so anyone can judge for themselves how trustworthy the method is. Thusfar I have had no reason to doubt the numbers I get to a great extent. Something I perhaps should not trust so much is the current reading from the power supply. The XP-G2 and XM-L2 measurements were done with a Peak switching mode power supply that can deliver 40A max. It has an inbuilt current reading that I used (I do not own a DMM that I trust the current reading from any better). This power supply is certainly on the budget side, but I would not expect a current reading that is 2A off at 8A .

Thanks for the information on the other Luxeons, it makes me more motivated to try to mount the LuxeonZ somehow and do some measuring on it :-)

On graph I see lux Q is around 240lm@1A,but Xp-e2 260lm?But you said you measure 240lm for xp-e2 which does make more sense.

It is known that cree drops more at higher temp. so you are right,this is one more important factor.

Well,it's time to buy one decent multimeterI wouldn't trust cheap power supplies,especially switching types.

I tested Lux Z ES,and voltages are much lower than xp-g2,so I expect the same with lux Z vs. Xp-e2.But nonexisting thermal pad is problem.

I'm sorry, I keep being inaccurate ;-) , I did measure 260 lumens at 1A for the XP-E2 R3, like the graph said. But mind that these measurements are done with my other power supply (a Kert, which I think is an ok one) that is difficult to set to the desired current, so a 1A reading could have been anywhere between 0.97 and 1.03A, this also creates some (minor, but everything adds up) noise in the numbers.

In theory, there are reasons enough to think of to distrust every bit of my amateurish set-up, but on the other side, the fair amount of measurements on various leds I have done using this set-up do produce numbers, trends and graphs that do make enough sense to suspect that it is not working that bad overall. For instance, if the currents that I read out would be off from a certain value on, I would see that reflected in a bump in the output-graph and the voltage-graph. But I don't see any of that. So apart from everything not calibrated well, and all numbers surely being off by a few percent I think that I sort of trust what I am measuring.

But it may be time to buy a very decent multimeter (instead of the ok multimeter that I have, it is not the worst of the worst, i paid 60 euro's for it at the time) for current measurements, so that I do not have to rely on whatever the power supply in use tells me. It is asked before on BLF, but does anyone have a suggestion for one that is not a 200+ dollar Fluke or Agilent (I can afford up to maybe 60 dollars), and does measure up to 10A accurately without introducing too much resistance? (I can make some monster-size leads myself :-) )

You have 60€ multimeter and you don’t trust it?
I have UT-71C and it was best price/performance at the time (maybe it still is,don’t know what’s popular these days). For <60$
this one looks good:
http://www.ebay.com/itm/UNI-T-UT-61E-Modern-Digital-Multimeters-UT61E-/300672753978?pt=LH_DefaultDomain_0&hash=item46017e213a
Good precision+true RMS.

hi, i currently work on…let’s say “dedoming device” so i’m in for giveaway, it will be interesting to try and slice something other than xml… :stuck_out_tongue:

Thank you for your research! I like to read about different LEDs; datasheets are boring. :bigsmile: I would like to try one of these Luxeon Q LEDs.

the giveaway, it just ended , and there's winners. 10 people showed interest, and I added Comfy because I guessed he would not mind one either :

random.coffeefilterholder.org did its magic on these names:

And the winners are:

I think that it would be neat if texaspyro puts one in his sphere as well, so I will send a sixth one to him as well . Winners, please PM me an address, I will send the leds on monday or tuesday.

[quote=djozz]

removing the phosfor at the sides of the die will produce a narrower beam, but the illuminance of the die (and thus throw) I expect not to increase. If you remove the surrounding phosfor straight up to the die there will be blue light leaking from the sides (should be cool looking in a reflector light )

[/qoute]

A hobby is there to try it all, and theory is not always what happens in reality, so here I went :

The result in stereo (@ Hbomb: the way I make these stereo pairs is just taking cell phone pictures through the left and right eyepiece of my stereo microscope):

I put the trimmed led in my Uniquefire UF-T20, and throw did improve, but just a bit: 73 klux@1 meter now, still way less than a dedomed xpg2 or xpe2. The hotspot was indeed much nicer without the yellow around it:

Last thing was to put the pill into a Convoy C8 host with a (Fasttech) smooth reflector that I have waiting for a friend's project. And the pill does not fit, wrong threading! A Fasttech C8 pill does not fit a Fasttech Convoy C8! (you C8-addicts thread boys already knew this of course). But with some fiddling and the bezel not quite screwed down I got it working for the test, I got 66 klux at 1 meter throw, with a OTF output of 376 lumen. (the C8 addicts I believe got around 100klux at 3A from a dedomed xpg2 or xpe2, up to 125klux with a xpg2 at higher amps) :

Nice hotspot though :

Well, it was nice messing about again with the led, but still no shock and awe compared to what is already there I'm afraid.

So it's not enough that you torture and kill emitters with current? You have to also slice and dice them? You, are a very very bad man.

Great work and pictures. Thank you for this excellent exploration into the Luxeon Q. I wonder if the manufacture will take note of your work. I hope so.

Thanks for the give away. PM will be incoming.

Oh, and very cool using a paperclip as a cutting guide. I think I'll be stealing that one... :D

for the giveaway.

I'm very happy to have the opportunity to measure a few things on the Luxeon Q (output and Vf @ 350mA, Tint color coordinates xc,yc and the final OTF output at perhaps 1.75A). I have an Integrating Sphere and a Color Analyzer to my disposal. I will post the results here when done.

Thanks djozz. I stand by my original post. Amazing dissecting on the led. There is not a hope in this world it would work again if I went near it with a scalpel.

Sure there is… just practice on yourself first… J)