As it relates to Cree Semiconductors:
Cree currently is manufacturing a line of power LEDs that they call the XLamp 7090 XR-E series. We on CPF abbreviate this to just "Cree XR-E." This chip uses a semiconductor die (That is, the semiconductor concoction that produces light when it has electricity run through it) known as the "EZ-1000."
Cree uses a binning structure that has a letter, then a number. The higher for both, the brighter the bin, for example P2, P3, P4, etc. The "P" bins are the best XR-E bins available at the moment, with P4s being the brightest. We are awaiting the "Q" bin XR-E parts, which so far have proven to be unobtanium.
Cree emitter parts do not resemble Luxeon packaging, but are available on familiar stars. They have a super-clear glass or silica lens retained by a metal ring, and a number of very small solder points. I believe the "slug," or thermal transfer point, is electrically neutral. Their radiation pattern is a 70-degree cone, if I recall.
As it applies to Seoul Semiconductors
Seoul Semiconductors is also currently manufacturing a new high-power LED. Somewhat confusingly, the Seoul Semiconductors (SSC) part is known as the "P4" series. So, saying "Seoul P4" is just like saying "Philips Luxeon" or "Cree XR-E." These LEDs are using the Cree EZ-1000 die, but are using a different phosphor mix to make the "white" light.
Seoul's binning structure is at present a mystery to me, but the parts that we have been seeing most often are "U" flux bins - this may mean they use a Lumileds-esque binning structure.
The SSC part seems to mimic much of the Luxeon packaging, appearing very similar in outward dimensions. They have a "gummy," or soft lens over the die itself, on which dust can settle and become "stuck." The lens is not as clear as the Cree part, although this does not seem to adversely affect the output. SSC P4 devices have a more-or-less Lambertian radiation pattern, which is similar to Luxeon devices. However, reflectors or LED heights have to be adjusted .030" in order to achieve correct focus with relation to Luxeon-designed reflector units. The "slug" on the SSC parts is electrically positive, necessitating the electrical isolation of the slug from heat sinking appratus, usually through nonconductive thermal epoxy.
My overlong .02 lumens!
I'm really sorry for asking such a dumb question, but:
, but I was hoping someone could shed some like on it. Thanks in advance. I'm learning (slowly),
So the name of SSC's series is actually P4, whereas Cree's equivilent to the P4 is the XR-E? Is that correct? Where does flux bin come in? The bin is the brightness category, right? Hmm..sorry...still a bit confused, but I'll get it eventually... 
Thanks everyone.
