XPG3 The upgrade?

saabluster

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I'll be honest. As much of a throw junkie as I am I have spent the last year almost completely ignoring anything throw related. It is not a change of heart as much a change of circumstance. Not being able to use the collar has been a let down. I know I know. Better to have loved and lost than to never have loved at all. Says the man who never lost his love. But it is hard for us as a species to go backwards in our material possessions and abilities. We are wired for one thing. Progress. Improvement.

And here we are with the latest improvement in the hallowed XPG line from Cree. The mighty XPG3. As alluded to earlier although I have known of this LED's existence I have all but completely ignored it. Things to do. People to see. It seems my disinterest was warranted. In the configuration that any self respecting throw junkie cares about(dedomed) the XPG3 has turned out to be a colossal downgrade. Worth only shoving into the spare bin drawer next to the Luxeon 3's and XRE's. I have sat back as many a pundit has attempted to ascertain why this paper upgrade is a real life downer. I have finally had enough.

One thing I never told you all was that I was one of if not the first to start dedoming LEDs. If you look back at some of my earlier announcements of record breaking lights this was a key component to most of them. Over the years I have developed many many solutions to the dedoming problem. In the early days when XREs were all the rage I made a connection with the water permeability of the silicone encapsulant and the properties of water itself. Basically I found an ideal soak time for the XREs in water that when extracted and exposed to high heat would flash steam and expand to separate the die from the encapsulant perfectly. Anyway I say this just to hint at a large toolbox of ideas that have been collected over years of research. This XPG3 has suddenly peaked my curiosity. Why I don't know entirely. To some extent it is the potential I see in this XPG3. The what ifs. It is also the challenge to tame the beast. I love a good technical challenge. Genuinely. It gets my heart pumping like nothing else. So I have made it my goal to find the hidden potential of this LED. I can't promise anything will come of it. But the search for answers will be immensely rewarding either way.

There is an end goal other than just the pleasure of discovery. Whatever I can glean from this investigation will be applied towards an upgrade of the DEFT-X/Victor line. I cannot at this time make new lights with the collar but there is nothing stopping me from applying the latest technology to already purchased lights. So I am currently attempting to create an upgrade path for older lights. I really don't know how far I will be able to take it or if I will be able to surpass the amazing level of performance of the Victor Enthusiast but I promise to do my best. I will inform you with more info when I have it. The tests are already underway. :)
 

dc38

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Where is that like button?

P.s., is there a way to use a combo lens system to maginfy the LED image and project it onto a focusing lens? Like with a telescope. It would probably cost more than those "appropriated" collar designs which would drive up end price, but there may be a way to match, if not exceed the throw from a conventional collar/lens design.
 

houser23

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I've been waiting for you to offer something like this. This is very good news indeed. Thanks Michael:popcorn:
 

saabluster

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Where is that like button?

P.s., is there a way to use a combo lens system to maginfy the LED image and project it onto a focusing lens? Like with a telescope. It would probably cost more than those "appropriated" collar designs which would drive up end price, but there may be a way to match, if not exceed the throw from a conventional collar/lens design.
I had such a system in very early DEFTs. It was what I called the precollimator. But this only works to boost the intensity if your main optics are subpar. Adding an extra lens to a well designed aspheric lens most likely will decrease the throw. There is no way to exceed or even come anywhere close to the effect provided with the collar using just optics.
 

Enderman

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There is a thread on the other flashlight forum of someone dedoming it and getting worse lux than the XP-G2.
This is probably due to the way the new XP-G3 is made with the phosphor over the whole die.

I still want more throw than my XP-G2 so I spent a few bucks for two XP-G3s and I will see for myself how they perform, I always like confirming stuff for myself.
First I will try with dome on, then I will try with shaved dome, but not dedoming because it seems like dedoming this LED pretty much ruins it.

I'm at 1.46Mcd with the XP-G2, so I'm really hoping a shaved dome XP-G3 can outdo it to reach the magical 1.5 million lux.
XP-G3s should arrive in the mail in a few days so I'll share what I find too in addition to saabluster :)
 

saabluster

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There is a thread on the other flashlight forum of someone dedoming it and getting worse lux than the XP-G2.
This is probably due to the way the new XP-G3 is made with the phosphor over the whole die.

I still want more throw than my XP-G2 so I spent a few bucks for two XP-G3s and I will see for myself how they perform, I always like confirming stuff for myself.
First I will try with dome on, then I will try with shaved dome, but not dedoming because it seems like dedoming this LED pretty much ruins it.

I'm at 1.46Mcd with the XP-G2, so I'm really hoping a shaved dome XP-G3 can outdo it to reach the magical 1.5 million lux.
XP-G3s should arrive in the mail in a few days so I'll share what I find too in addition to saabluster :)

Congrats on hitting the 1.4Mcd+ level. If you don't mind my asking what is your setup? I can confirm that the XPG3 dedomed performs horribly. Roughly 60% that of the XPG2. :barf: I'm not giving up this easy though. The underlying chip does appear superior so I want to see if there is any way to utilize it. My goal is to first ascertain WHY the poor surface brightness. I think it is going to be a multifold answer. Based upon my initial tear down of the XPG3 I believe the thickness of the phosphor layer itself is causing a decrease in surface brightness as the light is being emitted from a relatively large area thickness wise. I am also thinking that Cree is using a silicone with significantly higher refractive index to encapsulate the LEDs than they have in the past. The chips in these new LEDs have a smooth surface which to me seems really odd. Normally they would want to etch that surface to aid in light extraction. But I suppose it would not be as big a deal if they match the refractive index of the SiC chip. That would make it more difficult to get the light out of the package but the benefits may outweigh the downsides as the outer layer of the package would have the benefit of more perpendicular rays. If true then removing this dome would create essentially a "mirror" as the rays would be predominantly at shallower angles and more likely to bounce back down than to escape. The other issue I see is light leakage to the sides of the chip. The light exiting out the side would not in any way contribute to the top surface brightness.

My goals are to chemically treat the phosphor in many different ways to see if I can get a better result. I don't expect that to have a positive outcome but still. I am also attempting a phosphor transplant. Last I looked at encapsulants there was nothing available to me with a refractive index near SiC so I also need to look into etching the surface of the chip. I've got my work cut out for me.
 

vadimax

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Looking here:

Original-CREE-XPG3-S3-1A-1B-165LM-6500K-SMD-LED-beads-Cree-xlamp-Cool-White-flashlight.jpg_640x640.jpg


we may notice that phosphorus is being "dissolved" in the dome material as well -- it is not entirely transparent. So, if you dedome the LED, you kill its performance. Period :)
 

degarb

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Saabluster, too many technical points raised here for me to pass over:

Most importantly for me, is the water permability of silicone. This is something I need more education. As the debate between polyurethane (traditional v. Waterborne) , silicone, tripolymer (even amazing goop polymer), rages for new window trim out, to hardy board, to roof flashing, to water/snow proofing my boots, to ruggedized backside of my grinding leather gloves for an extra second warning.

Then, I have a vague idea if this collar from threads read years ago. . It has been discontinued?
 

Enderman

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Congrats on hitting the 1.4Mcd+ level. If you don't mind my asking what is your setup? I can confirm that the XPG3 dedomed performs horribly. Roughly 60% that of the XPG2. :barf: I'm not giving up this easy though. The underlying chip does appear superior so I want to see if there is any way to utilize it. My goal is to first ascertain WHY the poor surface brightness. I think it is going to be a multifold answer. Based upon my initial tear down of the XPG3 I believe the thickness of the phosphor layer itself is causing a decrease in surface brightness as the light is being emitted from a relatively large area thickness wise. I am also thinking that Cree is using a silicone with significantly higher refractive index to encapsulate the LEDs than they have in the past. The chips in these new LEDs have a smooth surface which to me seems really odd. Normally they would want to etch that surface to aid in light extraction. But I suppose it would not be as big a deal if they match the refractive index of the SiC chip. That would make it more difficult to get the light out of the package but the benefits may outweigh the downsides as the outer layer of the package would have the benefit of more perpendicular rays. If true then removing this dome would create essentially a "mirror" as the rays would be predominantly at shallower angles and more likely to bounce back down than to escape. The other issue I see is light leakage to the sides of the chip. The light exiting out the side would not in any way contribute to the top surface brightness.

My goals are to chemically treat the phosphor in many different ways to see if I can get a better result. I don't expect that to have a positive outcome but still. I am also attempting a phosphor transplant. Last I looked at encapsulants there was nothing available to me with a refractive index near SiC so I also need to look into etching the surface of the chip. I've got my work cut out for me.
Thanks!
Currently it's built inside a PVC sewer pipe, dedomed XP-G2 S4 2B, 6 amp mountain electronics buck driver, a large cylindrical CPU heatsink with a fan, 70mm wavien collar, and a 100mm fasttech aspheric lens.
Quite the setup :) Before I was running the XP-G2 direct drive to a 4.2v lipo but it was only drawing 3-4A and I only got 1M cd, the 6A driver is doing wonders.
I need to get some pictures together and post it on this forum, but if you want to you can see some pics on this other forum: https://linustechtips.com/main/topic/442305-the-lightcanon-flashlight/

My orinigal theory about the XP-G3 is that dedoming it took off a layer of phosphor, but if you read the post above it might actually be that the dome itself contains phosphor in it?
If so, even dome shaving would reduce the output.
Will find out soon I guess...


Then, I have a vague idea if this collar from threads read years ago. . It has been discontinued?
Wavien disappeared, their site is up but there is no store anymore and apparently people have tried to contact them with no reply.
All it is is a hemispherical reflector with a hole in the middle, so if you really want one you can get someone like phoenix or optiforms to make you one and it should work just as well.
 

saabluster

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we may notice that phosphorus is being "dissolved" in the dome material as well -- it is not entirely transparent. So, if you dedome the LED, you kill its performance. Period :)
The dome is entirely transparent. The phosphor is all in a conformal coating.


My orinigal theory about the XP-G3 is that dedoming it took off a layer of phosphor, but if you read the post above it might actually be that the dome itself contains phosphor in it?
If so, even dome shaving would reduce the output.
Will find out soon I guess...
No phosphor in the dome.

I did some tests on the XPG-2 and XPG-3 to try and ascertain how much surface brightness loss there is and what it can be attributed to. The numbers are just arbitrary taken from my light meter readings with the two LEDs being run in series to assure equal current.

Surface brightnesscomparison
XPG-2 S3 8.6
XPG-3 S5 7.1

Corrected surfacebrightness (like for like binning). Shows effect of differing phosphorapplication.
XPG-2 9.8
XPG-3 7.1 = 38%decrease in surface brightness with dome on.

This means a huge reason for the decrease in surface brightness is due to phosphor application and in my opinion lateral light leakage. I performed a phosphor transplant an hour ago and will report my findings later once the silicone has cured. On one XPG-3 chip half has a completely new phosphor while the other half is split between shaved and shaved plus silicone sealant cover. Will be interesting.
 

saabluster

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Here are the results of my testing on the XPG-3.

All dedomed
XPG-3 modded with the one chip subdivided into three distinct sections.
Stock shaved 3.3 -57% dec over XPG2
Shaved plus thin silicone coating 4 - 48% dec over XPG2
Transplant 4.7 -39% dec over XPG2
XPG-2 S4 7.7

As you can see it seems this LED may have nothing to offer us throw junkies. My modifications did indeed make a positive improvement but not enough to bring it anywhere near the performance of the XPG-3 S4 which is even one performance bin below the S5 XPG-3. I was surprised to see my mod increase the performance 42%. Everything I'm seeing in this data is confirming my initial thoughts as to the reason this LED has such horrible surface brightness. I could probably continue to improve the performance by honing the phosphor transplant but my guess is that even if I were able to get it as good as possible the numbers would still be lower due to light leakage. Tis a sad day.
 

Enderman

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Welp, that sucks.
This is probably also the case with the XP L2 then...

I don't really understand how you "split" a single die into different sections with different coatings...or how that gives you an accurate number of the total LED intensity compared to a full XP-G2...
 

saabluster

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Welp, that sucks.
This is probably also the case with the XP L2 then...

I don't really understand how you "split" a single die into different sections with different coatings...or how that gives you an accurate number of the total LED intensity compared to a full XP-G2...

I shaved the XPG-3 down to within a hairs breadth of the chip leaving a thin layer of phosphor. Then I removed the phosphor over half of the chip. In its place I added phosphor from another LED(in this case a Luxeon). And then on the side that still had the original phosphor I coated half of that with a thin layer of optical grade silicone. That gave me three distinctive zones on one chip.
 

Enderman

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I shaved the XPG-3 down to within a hairs breadth of the chip leaving a thin layer of phosphor. Then I removed the phosphor over half of the chip. In its place I added phosphor from another LED(in this case a Luxeon). And then on the side that still had the original phosphor I coated half of that with a thin layer of optical grade silicone. That gave me three distinctive zones on one chip.
And then... you blocked out zones to take your lumen measurements to calculate the intensity per area?
tbh I would have just done 3 separate LEDs one for each method to have consistent results with no confound variables...
 

saabluster

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And then... you blocked out zones to take your lumen measurements to calculate the intensity per area?
tbh I would have just done 3 separate LEDs one for each method to have consistent results with no confound variables...
Using 3 separate LEDs adds a variable. Doing it the way I did reduces the variables. I have a chip with a known output and the only variables are the phosphor types. Testing each zone is super easy. I use a short focal length lens and only project the desired zone over the light meter's sensor. I can get very accurate readings of even small areas of each zone.
 

KITROBASKIN

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Very interesting reading about the process of evaluating an LED for enhanced throw.

Have you explored crafting a thrower with an outstanding tint? Is a shaved Nichia a possibility? I've heard that the dome on Nichia emitters is not suitable for manipulation.

Thanks again for this thread.
 

saabluster

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Very interesting reading about the process of evaluating an LED for enhanced throw.

Have you explored crafting a thrower with an outstanding tint? Is a shaved Nichia a possibility? I've heard that the dome on Nichia emitters is not suitable for manipulation.

Thanks again for this thread.
Generally speaking people seriously into throw aren't as concerned with high CRI. Not that aren't some out there but that would be a niche within a niche.

I haven't given up on this stupid LED. I performed yet another phosphor transplant today using a Cree phosphor this time. I'm stubborn and curious to know how much I can improve it.
 
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