theatrus
100-mile-commuter
Where they the "domed" units (large bulky things with gull wing leads) or the silicone topped type?
The domed units are what I would expect for failing, marginal, or low bin chips coming off any fab line (even possibly Bridgelux). They get bought on a secondary market, retested under less strict criteria ("does it light up?"), and wire-bonded into a generic adaptable case. I'm not sure what you're getting, and there is probably a lot of variance.
The silicone topped units may be straight from a mainline manufacturer, though I'm sure packaging houses that specialize in second runs or non-premium stock have started encapsulating that way too (especially if they're trying to play in the knock-off market and make it look like a Cree).
I'm not aware of LED dies being marked in any particular way with manufacturer marks (like you find in ICs), but I'll do some research with a few contacts I have to see if there are any tell-tale signs. I also don't have the needed microscope power to resolve the details needed here
.Unless you control your supply lines in China very very carefully, its easy to get substandard, second run, or plain fake parts which looks just like the originals. Its happened to a past company I worked for with electrolytic caps, and it was even a knock-off of a reasonable Chinese brand (Samxon) that ended up in products. The distributor didn't cross their Ts and accepted parts that weren't the real deal, and passed them on, which then failed in four-corners burn in testing at a high rate, meaning a few thousand units needed manual rework. Its all about establishing trust, and eBay vendors aren't high on my list of people I can trust implicitly
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