Lumileds Luxeon V, test of a 4000K 70CRI emitter

Your suspicion sounds quite plausible, but lack of variation does not seem to rule out separation. If there is some defect in the dome adhesion process, it could result in similar looking failures.

EDIT: Fixed typo. Didn't include the word "not".

Cool. I don't think djozz was trying to say you caused the damage. I thought he was just asking a reasonable question to gain data. I imagine dome separation could be caused by a defect in the manufacturing process. That could explain how I could beat the hell out of mine with no failures, while other emitters failed for no apparent cause.

Ok, I was impatient (as mostly) and “cold” dedomed the LED including phosphor using my fingernails and tweezers.
Was hard to take close pictures with my low end smartphone but finally I put it on top of the lens of my 3rd hand which also (hopefully) helped to keep my eyes undamaged since I don’t have UV protection glasses. This is the (still ugly) result:

The orientation of the 2 pictures might be different since I moved the MCPCB after taking the first picture.
It’s only the inner square of the LED surface which is lit and I can only see a small difference between the halfes. But I powered the LED with a couple of milli amps only since otherwise my smartphone camera had been blasted. Might be there is a bigger difference at higher currents.

Edit: in the 1st picture the LED is not powered and the inner square doesn’t look patterned as seen in the picture, it’s even.

Actually the inner square is not completely even. Take a look at my first picture, you see a vertical line, a tiny bit left from the middle of the inner square. You don’t see it clearly with naked eyes, but with my tiny microscope there is very narrow line visible. It doesn’t appear to be a crack, more like the remaining kink in a paper sheet which has been folded and unfolded again, somewhat elevated. Don’t know at all the meaning of this, perhaps a conductive trace underneath the kink has been blown.

So it looks like the fault is in the die? The Luxeon V may be a double die led? Or so? And you can (partly) blow up one and the other keeps going.

Maybe…
But the strange thing is that when you do a continuity test (polarity check / “beep” it) with a DMM the whole thing does light up like any other LED.
Only when you push more current through it (like 150mA or more), the problem becomes evident.

Now we're starting to cook with gas. Thanks to Flashy Mike's and Jerommel's last contributions we know a lot more. It looks kind of like a layer is not properly lined up. Here is a diagram of some other type of chip scale package LED. I like it because it gives a sense of how the electrical pads connect to the layers that create light and, therefore, how come these types of emitters are so much harder to fry (due to connection with no bond wires).

What doesn't jive with that possibility is that Jerommel had an LED that initially didn't manifest the failure.

EDIT: Maybe the phosphor doesn't hold up well to the layer it is resting on that should normally be covered by another material. So over time the defect reveals itself.

EDIT2: I unpackaged my remaining 6 emitters and just momentarily tested them at 200mA. None appeared to have the defect. All 10 of my emitters are the 4K tint from Mouser. I want to again thank Flashy Mike for taking one for the team to help gain insight into this issue.

@ImA4Wheelr:
Thanks for your efforts, too.

Meanwhile I found my notes from my first tests with the Luxeon V. What I see there is a loss of about 33 to 36% both in max current and lumens after the damage occured - which is very close to a third. I have to concede that I’ve driven 2 of the LEDs pretty hard for test, up to 10 Amps which is not recommended at all. All LEDs have been ok on delivery, 2 went bad pretty fast, another one somewhat later in a light which has been driven with less current.
Btw. the highest lumen measurement I got (before the LEDs got damaged) was about 1800 lumens in a X3 at almost 10 Amps. Less than I expected.

I measured just over 2000 lumen at 30 seconds in a Thorfire VG10, at 9A. Mind that my lumen is probably about 9% high compared to official calibrated measurements (and low compared to other BLF and flashlight manufacturer calibrations), so your 1800 lumen is quite similar.

More great info. It's probably way to tiny to detect, but do you see any signs of delamination (layers separating) on that dedomed emitter?

How does the Luxeon V compare to the SST 40 as far as throw?

Now I have a Luxeon V without phosphor left. It emits UV as I learned. Which wavelength should I expect?

450nm (royal blue), UV is <400nm.

Thanks. Is this valid for all white LEDs (with phosphor removed)? I could make royal blue LEDs by myself then (I ordered royal blue for my D4 RGBW, but they didn’t show up yet). Protection glasses not required, I guess?

Are LED4POWER’s custom MCPCBs so far all there is for a good fit with these Luxeon V’s?

My understanding is that most white emitters use a Royal Blue emitter (not sure of peak frequency at the moment). There was an LED that was to center around 410nm by SORAA LED. I don't know if it ever came out. Here was a thread on it:

https://budgetlightforum.com/t/-/40456

Did you see my question in Post 127 above?

Imagine Emisar D7 with 21700 Samsung 30T, copper sandblasted head, anodized aluminium sandblasted body, copper dtp board for 7 Luxeon V emitters together with Ledil ANNA 7up spot optics! :innocent:

Is D7 released light? I will probably make a new batch of mosX boards next month, I already have few boards that I'd like to make,if there is enough interest I can add few other designs.

D7 is not yet released but as far as I know it should use 3x18650 and 7 emitters I suppose judging by name. I would love to see 21700 design though! In my opinion Emisar series should be single cell lights and Noctigon series multiple cell. I hope we will find out soon what D7 will look like!

I would love to see 7 luxeon V mosx boards compatible with Ledil ANNA! It’s the way to go. I am very optimistic in believing that in 2018th we will se more 20700 and 21700 single cell flashlights.

Btw I’ve built S2+ triple luxeon V with your parts led4power. I saw 16.2A with my Uni-T UT58E with extra thick 3.6mm short speaker wires and vtc5a. Output is insane.
Should be 5500 led lumens being on a conservative side. If 20% is lost (I am not using lens in front if optic and I I grinded lip to have optic and exposed as much as possible) I should be getting 4400 lumens OTF :partying_face: