White Luxeon LS phosphor(s)

In the published data for White Luxeon and Nichia LEDs the spectral power distribution is very similar with the exception that the Luxeons have a prominent narrow peak at around 610nm that is not present in the Nichia spectrum. Nichia uses YAG as the phosphor but I have not seen any Luxeon literature that discusses their phosphor choice. It appears that they may be using a mixture of YAG and a second phosphor that gives that 610nm peak. Does anyone know?

Here are a couple of EARLY spectra I got from a white Nichia LED and a white Luxeon Star, taken shortly after I first got my spectrometer.

Note, this was BEFORE I had correction software written to quell a nasty response hump that was showing up around 700nm, and BEFORE a second program was written to get rid of those asinine nanometer intervals along the X-axis.

I'll see if I can re-take these tonight.
I know I have at least one white LED spectrum that has the corrections applied, but I can't seem to find it at the moment.

Bumping this in case anyone in the know missed it the first time.
Craig, while a bit off the original topic, do you remember if the color quality of the Luxeon you tested to get the above spectrum? It would be interesting to see the spectra of white and PG-white Luxeons compared. You are probably the only one here that could provide that info.

I'm pretty sure it came from one of the user mods, like the Lambda Illuminator. Newer style optic. I do remember it was a "good" Luxeon, not the kind with the rotten dog urine color to it.

If I can find the original .SPE files for these, I can apply the new correction filters to them and come up with more accurate plots.

Nice to see this topic back up again. Got a question to add here too:

Does anyone know *why* the luxeons suffer so badly in terms of color consistency? Is it the thickness of the phosphor application causing this or the composition of the phosphor itself? Or ... *shudder* are they having problems with the basic blue die underneath the phosphor - or all of the above?

I would like to know that too. Are the Luxeon/O that are being made now have that icky green color still, or did they fix that problem?

http://www.lumileds.com/pdfs/techpaperspres/IEEEJSTQE-HighPowerPCLEDs.pdf

Artical you all may like.

Originally posted by McGizmo:
Doug S.,

I am so glad you assimilated this document! Good to know there are folks here who can handle such material.

After taking a look at the article, for me, it was a toss up; digest this article or tackle Tolstoy in sanscript. I opted for Tolsty.

- Don

Click to expand...

<font size="2" face="Verdana, Arial">Don, you crack me up! I must admit, in a few places I considered the Tolstoy option too.

You mean Sanskrit? Russian is in Syrilic I think. Sanskrit is in Bhagavad Gita or something like that. Trying to be helpful.

Originally posted by Marked:
http://www.lumileds.com/pdfs/techpaperspres/IEEEJSTQE-HighPowerPCLEDs.pdf

Artical you all may like.

Click to expand...

<font size="2" face="Verdana, Arial">Marked,
Thanks for the fabulous link. This was fairly heavy reading. It took me a pot of coffee and a couple of readings to fully assimilate this. Since this paper was written by the Lumileds guys [and gals] I strongly suspect that figure 14 hints at the answer to my original question. It does appear that they are adding a second, red phosphor to their white LEDs.

Doug S.,

I am so glad you assimilated this document! Good to know there are folks here who can handle such material.

After taking a look at the article, for me, it was a toss up; digest this article or tackle Tolstoy in sanscript. I opted for Tolsty.

- Don