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 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. 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. I also don't have the needed microscope power to resolve the details needed here :). 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. 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 sure what you're getting, and there is probably a lot of variance. They get bought on a secondary market, retested under less strict criteria ("does it light up?"), and wire-bonded into a generic adaptable case. The domed units are what I would expect for failing, marginal, or low bin chips coming off any fab line (even possibly Bridgelux). Where they the "domed" units (large bulky things with gull wing leads) or the silicone topped type? That is exactly why i asked, somone gave me a fixture that the drivers failed on (the dont like to go swiming) so i took all the LEDs off of it, In short, I have no idea if those LEDs are actually Bridgelux or a knockoff or a totally different die branded as Bridgelux because it's a familiar name.įor a fun read on this branding problem but with SD cards:
There was a patent lawsuit between Cree and SemiLEDs that settled in favor of Cree, barring the import of certain SemiLEDs products.
They make several spectral points, but no violets (despite seeing vendors claim stock they selling are Epistar 420nm, at $0.50 a package ) The other brand I see a lot is Epistar, which is a Taiwanese local manufacturer. I am unsure if Bridgelux sells phosphor coated chips, so who knows what phosphor you might be getting. Someone in China can take the actual chips and package them of course, except Bridgelux specializes in lighting so they will be 450nm only units.
As for packaged units, they really only market white COB modules, at least domestically.
Bridgelux specializes in GaN on Silicon chips which are their special sauce and much cheaper than the normal sapphire substrate for blue. I've always wondered if those are actual Bridgelux units.
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