New XR-E has smaller die?

[bshanahan14rulz]

I just got two LEDs from a chinese distributer. They were both marketed as R2 (have my doubts about both) but they look different. Both are the silver-backed versions, both have same tint (according to seller), same color phosphor, both are the xr-e die with the three bars and 4 bondwires, same metalic-looking substrate that is more rectangular. Difference? die size. One's die was almost as wide as the substrate in one dimension, while the other die had a smaller area and left a copper-colored square on the substrate that would be covered up had a normal sized die been used.

Has anybody else noticed this on your LEDs? (easy way to tell: look for copper square around die) Anybody have any insight into which of my LEDs, if either, is the R2? the smaller one seems brighter, but I think it throws a smaller spot..

 

[Illum]

The only LED I know that has the exact same external appearance to the XR-E is the XR-C [see different between an XR-E and an XR-C ]
But I don't recall anything copper related

if not, no...I have not heard of it:candle:

 

[ergotelis]

If only you can post some photos!

 

[bshanahan14rulz]

I will have to remember to bring these in for picture taking. for the moment, all I can do is photochop. So these are photochopped versions just to give you an idea of what I'm noticing. They are not xr-c because the die has same pattern as xr-e, just smaller. xr-c only has 2 bars in the middle, xr-e has 3.

Credits to Illum for image from pictorial review of LEDs thread that I photochopped. (lol just noticed you posted in my thread too! :wave:)
These pictures are pretty accurate representations of what my LEDs look like. And I lied, I MSPainted, not photochopped. sue me. Anyways, the copper-colored metal is the same as the silver piece, just looks like copper, almost like it was plated silver but they left some space for the die or something. Also note that the outer inverted-U shape on the die is present on both dies. the dies look exactly the same, just one is smaller. And it might just be my eyes can't see that small, but I could swear that the + sign left of the die on the silver thing is a square on mine.

Larger Die

Smaller Die (MSPainted)

 

[taschenlampe]

Looking at the bonding wires I would denote this picture is a fake ...

tl

 

[ergotelis]

he said photochop... he took a picture,cut the core of the led,made it smaller to tell the difference, not the original photos of course..But we still do need the original ones!

 

[mds82]

post both pictures side by side. the 2 pics you posted also are taken from different angles so its hard to see

 

[phantom23]

http://www.kaidomain.com/ProductImages.aspx?ProductId=9033
http://www.kaidomain.com/ProductImages.aspx?ProductId=8324
Second pictures in both links - orange edging is clearly visible.

 

[bshanahan14rulz]

Good pictures, thanks for the link, phantom. Yes, my LED looks like that. My other LED the chip seems to be closer to the long edge of the substrate. I'll have to bring them into work tomorrow to take pics w/ friend's camera phone. Any factual evidence or even speculative ideas as to which is the real R2 or if they both are, or why cree would do this?

Edit: btw, yes, the two pictures I posted are from the same angle. and yes, they are the same picture, but "photoshopped" to show what I was talking about.

 

[saabluster]

http://www.kaidomain.com/ProductImages.aspx?ProductId=9033
http://www.kaidomain.com/ProductImages.aspx?ProductId=8324
Second pictures in both links - orange edging is clearly visible.

Good job catching that.

Good pictures, thanks for the link, phantom. Yes, my LED looks like that. My other LED the chip seems to be closer to the long edge of the substrate. I'll have to bring them into work tomorrow to take pics w/ friend's camera phone. Any factual evidence or even speculative ideas as to which is the real R2 or if they both are, or why cree would do this?

Edit: btw, yes, the two pictures I posted are from the same angle. and yes, they are the same picture, but "photoshopped" to show what I was talking about.

I have never seen any XR-Es that looked like that. Not saying it hasn't happened before but it seems unlikely that this is some random fluke that happens in production every now and then. That wouldn't explain the two pictures bshanahan14rulz posted and the LEDs you received. What are the odds right? So here are a few theories. Theory #1 You have counterfeit LEDs. I doubt this is the case but it could happen. Theory #2 Manufacturing variance. Considering the available evidence I also feel this is unlikely. Theory #3 This one we will break up into two parts under the idea that these are genuine Cree LEDs. #3A Cree has merely made a slight design change in the way they produce the XR-E. #3B Cree is making the SiC, that the LED sits on, bigger so that the new XP-G's die can be used in the XR package.

Assuming that the LED die is in fact an XR-Es the SiC base in those pictures is larger than all the ones I have seen. This is what makes me think it may be the new XR-G SiC base being used across the board with the XR-E die and what you see around the edge is the excess solder pad for the larger die.


Of course none of the above may be correct. What is clear is that we need some really good close-up shots of what you have.

 

[Illum]

http://www.kaidomain.com/ProductImages.aspx?ProductId=9033
http://www.kaidomain.com/ProductImages.aspx?ProductId=8324
Second pictures in both links - orange edging is clearly visible.

hosted over




interesting...I wonder if that helps with heatsinking at all:candle:
More than likely it may be a form of marker, but more often than not appearances like this would have been previously thought of as a fried [or fully cooked] XR-E

 

[bshanahan14rulz]

I like SaaBlaster's idea 3A, or whichever was about updating the package to be able to work with both ez1000 and the new larger dice used in xp-g. I brought both LEDs to work today, but all we have is a 3G-S camera, and I can't find my TSX clear aspheric to help magnify >.<

Saa, are you used to using american cree or chinese cree? Someone here stated that american cree emitters have phosphor over the entire visible substrate under the lens, while chinese cree emitters have a silver back.

 

[saabluster]

I like SaaBlaster's idea 3A, or whichever was about updating the package to be able to work with both ez1000 and the new larger dice used in xp-g. I brought both LEDs to work today, but all we have is a 3G-S camera, and I can't find my TSX clear aspheric to help magnify >.<

Saa, are you used to using american cree or chinese cree? Someone here stated that american cree emitters have phosphor over the entire visible substrate under the lens, while chinese cree emitters have a silver back.

I have both but mainly the silver backs.

 

[bshanahan14rulz]

Ok, folks, not the best shots, but my friend at work says he has a nicer camera that should be able to do macro, although not both at the same time unless it's sunny again... perhaps I should finish up that mag mini mod as a bribe...

The LEDs are oriented at the same height. I also noticed that the angle between the bond wires that go to the top of the die is smaller on one, and as expected, it is the smaller one. the domes look exactly the same in profile.

First pic, kind of blurry, camera is not quite centered... kinda closer to the larger one on the left

Second pic, also kind of blurry, camera is more over the smaller one now

Third pic, sharpest pic, directly over the smaller one.

Ok, honestly, I was trying to have it centered the whole time except that last pic, so the first two pics didn't show up too well, the third pic doesn't show the larger die too well, Sorry, perhaps better pics tomorrow.


P.S. to SaaBlaster: I couldn't tell for sure, but I don't think that the SiC looks any different in size... I am assuming the SiC substrate is only that rectangle with the + mark on it and that the die sits on

 

[Helmut.G]

#3B Cree is making the SiC, that the LED sits on, bigger so that the new XP-G's die can be used in the XR package.

+1
that's what I thought
could be possible

bshanahan14rulz, skip the "normal" left one if you take more pictures, just show us the interesting die, as big as possible :huh:

 

[bshanahan14rulz]

I'll see if I can do that tomorrow. Looks to me like substrate is same size. bond wires look like they diverge less. I mean, it's obvious that the image of the die is smaller from one compared to the other because the 3 small rectangles are smaller, but since everything else in there looks the same size, my brain concluded that the die is smaller. I'm kind of surprised nobody else has noticed this yet. It seems like it would be important for those of you who are very precise with your builds, esp. the thrower crowd, who need small area to throw better. People, get all your various assorted LEDs and give 'em a good looking over.

 

[Marduke]

I recently got a K-106. Looking close, and lo and behold it has the smaller die. At first I thought they changed the dome geometry, so from looking from the outside it just has a smaller apparent die size, but looking closer it's only the die itself that looks smaller.

At least that's how it looks by the naked eye.

I suspect it has something to do with the newer XP-E and XP-G series.

Oh, and I do see the exposed copper pad area as well. So no, you are not crazy.

 

[saabluster]

I recently got a K-106. Looking close, and lo and behold it has the smaller die. At first I thought they changed the dome geometry, so from looking from the outside it just has a smaller apparent die size, but looking closer it's only the die itself that looks smaller.

At least that's how it looks by the naked eye.

I suspect it has something to do with the newer XP-E and XP-G series.

Oh, and I do see the exposed copper pad area as well. So no, you are not crazy.

Although I may be right on this that is hardly evidence that I'm not crazy.:p Looking at those pictures it looks like there is more going on though. If they are both XR-E dies then the base being larger does not explain the fact that one die appears much smaller. So either the small one is an updated XR-C die or there are other changes such as the index of refraction of the gel and glass used to encapsulate the LED causing a reduction in the magnification.:shrug: I don't know. Just thinking out loud.

 

[Marduke]

Well, it looks like the base is the same size, but the physical die is shrunk. Perhaps they did something to shrink the EZ1000 dice for the XP-E and no one noticed the small change before, or attributed the slightly different look to the dome shape difference between the models.

It is possible the base is larger and the die is the same size, but then the geometry or materials of the dome would HAVE to be different.

 

[znomit]

Can they change the die and still call it an XR-E?
A smaller brighter die may give the same lumens but none of the current optics would give the same beam.