I venture to say there is no one person here that knows more than me about all the major LED products all the way down to the technology used at the die level.
I would have no problem venturing that I have every bit as much if not more knowledge about LED products on the market, what is coming down the pipe, and yes how LEDs work all the way down to the die level. That is the benefit to working with them on both a technical and business level virtually as long as high powered LEDs have existed and for a few years beyond that as well. It is also the benefit to having a corporate LED spend somewhere in the range of a million USD. No I am not going to reveal who I work for. I am on a first name basis with many senior people at Nichia, Lumileds, Cree, Seoul, Bridgelux, Luminous, etc. I don't mind sharing my opinion (and non NDA information) with the community, but I need to maintain my relationships too.
I think if you read through my posts it is obvious I know what I am talking about.
I made a quick comment about the Rebel-ES to clarify what I was talking about. The object of my post was not to compare the ES to the XPG.
In terms of availability of the R3 bin and "just asking for it" from Cree, I have done that. Your comment "I seem to remember that if you are big enough you can go straight to Cree" ... tells me that you are not that tied into what is available. My comment about availability comes from those discussions. Yes I can get them, but not in the consistency and price range I need. I am still waiting on similar confirmation from Lumileds on the 120 bin Rebels.
By massive quantities do you mean 100's or 10's (or 100's) of thousands? Cutter is not a high volume distributor. When I consider volume I mean at a minimum 10's of thousands.
Since you are comparing to a R3 bin Cree (CRI 75), you really need to compare to a 120 lumen Rebel cool white CRI 70. Lumileds generally does poor on their lower CRI parts because they have a hole at 460-490nm. At longer wavelengths their phosphor tracks pretty well with Crees.
We use XRE as well in a few of our legacy products and will not be changing them due to the unique optical properties which no one seems to be replicating except perhaps OSRAM.
In terms of the heat degradation between XPE/Rebel, since you do some many tests, you should have this already... ;-) ... We have a somewhat proprietary die temp measurement system that pulses the die off for very short periods of time and uses a thermal camera to measure the package and into the die during these periods. The off time is very short to ensure the temp is consistent. The techniques we use are somewhat like lock in thermography in order to get high accuracy. That is about as much detail as I can reveal.
For most of our products the output versus die temp does not make make of a difference in output, but for some of our specialty products where we drive them hard, it does start to impact performance. This would not be unlike the high performance flashlights that people on CPF like to play with hence my comment.
The other issues I run into with the XPE and XPG (not XRE) is that I am somewhat forced into a metal core board for higher temp and drive products. The Rebel is far more amenable to a FR4 with vias thermal design while still achieving very good thermal transfer results. That lets me keep my costs down for most of my products. My customers are still more concerned about dollars/lumen versus lumens/watts for 90% as long as the product has reasonably good efficiency. They also like consistency of color and hence Nichia tends to be a strong player for us for mainly warm white. We are split pretty equally between Cree, Lumileds and Nichia with a few niche products based on other LEDS.
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