Very interesting CoB from Lumileds, it's unique because it's designed to be under BBL/with negative Duv (I think this is the only LED after some Nichia 219Bs with "factory default" negative Duv):
Duv of ellipse centers in -0.0042 to -0.0052 range at 85C, which sounds perfect, not too rosy, and if this CoB has very stable tint over temperature and current like most other Luxeon LEDs, then Duv will stay negative under all conditions.
Efficiency is quite high too- 135lm/W @85C
Overall sounds like a great CoB LED, but as usual its use in flashlights is potentially very limited due to LES size and Vf as with most CoB LEDs.
At least it seems manufacturers start to "copy" what flashlight enthusiasts are doing for some time, it reminds me of quite similar story with undomed LEDs.
Who knows, maybe they finally make some high power 3V LEDs with similar properties as this CoB?
Some (maybe most) samples of the Luminus SBT-70 "WDH" (5700K, 90CRI, R9>85) and very likely also the CBT-90 and CBT-120 (all from ~2012) with the same properties have a tint under the BBL. Unfortunately these are just about the most ineffcicient LEDs you can get.
I do hope though that we will get more LEDs with nice tints in the future. These COBs look nice.
Yeah, comparing the smallest one, at 9mm diameter die size, to a 36V MT-G2 Q0 at 300mA, the MT-G2 beats it in both efficiency and total output. But, it’s a new line, right? Perhaps more improvements can be made? With the pretty round LES, it still might be nice in a big light. Obviously, area lighting would be a better use for it, but I wouldn’t count it out yet for flashlight use, or at least searchlight use.
Having a high CRI and negative DUV will make it very attractive to some BLF’ers, even with a large diameter LES and low relative output.
I was comparing it on output alone. The MT-G2 was extremely popular here in the past, so a lot of BLF'ers remember what it's like, and some BLF'ers still like it a lot. The high CRI of this COB makes it more desirable to people that care about that. And high CRI is known to result in lower output, so it would be even closer to the output of the MT-G2 if their CRI were the same (this one were lower and/or MT-G2 were higher CRI). Even just as they are, this COB should have output not far from that of the MT-G2. But, of course, modern high power single die emitters would blow it away in raw performance.
Efficiency of the 80CRI Luxeon Cob compared to MT-G2 Q0 bin (highest bin of MT-G2 just in lowest CRI) is almost identical, 80CRI MT-G2 is available at max M0 bin which is 18.5% lower efficiency.
But these are hardly comparable leds, the MT-G2 was very compact with lots of light density for a Cob and so much more suitable for general flashlight use than these Cobs meant for floody general lighting.
