Link to Lumileds paper on the future of White LEDs

Here is a link to a paper on this subject. Note: it is a bit technical, long, in PDF format, and contains a few errors [sloppy proofreading]. It is worth a read if you have the stamina for the technical stuff.
http://www.lumileds.com/pdfs/techpaperspres/OIDA_28May2002.pdf

MrAl,

1. That issue was addressed on page 23 of the paper. They acknowledge that they are having thermal epoxy failures.

2. When people are beating down your door to buy your product, quality control suffers. It's not good, but it happens. As somebody who has to replace diminished quality products on demand, I am not happy with this, but I have to live with it. If Lumileds offers me a handful of 5W parts that are even slightly white tomorrow, I will buy them because I have customers screaming for them.

Further, on page 10 of the paper, the author addresses the question indirectly by noting that with UV LED + RGB Phosphors "White point determined by phosphors ONLY! (i.e. tolerant to LED variation)". Lumileds is certainly not advertising unwanted color variation, but they are not dismissing it out of hand or hiding it.

It seems ungracious to describe the producer of the best white LEDs available as comical on this forum. Especially since that paper was presented on the 28th of May, well before the 5W white parts problems were determined unsolvable in the near term. Remember that 500 hours is about three weeks of continuous testing and represents a tremendous committment of resources to verify.

Lumileds is doing great things for us. Please don't be mean to them.

Check out page 19 of this document:

http://www.lumileds.com/pdfs/techpaperspres/IWN2002.pdf

72 lm/W on Orange!

170+ lm in cyan, green, and white! (5W)
187 lm from a 5W white! (driven at 4.2 W)

-Darin

Also, look at page 16 of the same presentation - they show a 1W pushing 4W (in CW operation, which I assume is similar to using a PWM)

-Darin

Looks worthwhile. Thanks Doug!

Hello there,

I found that link quite interesting, but just a tad comical.

I especially liked the page on "LED Skulduggery", where they forgot
to mention at least two things in "What am i hiding":

1. Publishing papers that have charts that say 20,000 hours lifetime
when some of their's only have 500 hours lifetime.

and

2. Calling all LED's that emit something that looks like white light
"White LEDs" when really they put out a greenish tinted white light.

Good luck with your LED circuits,
Al

IMHO
CW is "Continued Wave", in DC current operation will be "continud current".

Hello there,

shipinretech:

I dont quite understand what you meant by
pointing out page 23 or even the other page,
but i guess i should have mentioned some things
i liked about the products as well.

I have found that i would prefer pure white
light, but if i had a choice between a violet
tint and a green tint, i have to choose the
green tint (which Lumileds seems to be making
these days). The reason is i have found that
the greenish tint renders color coding
(such as used on resistors) a bit better
then the violet tint. Now this has been
deemed "puke green" and such by others, but
i have found it to be more useful for my own
applications.

What i dont like is that the new 5w not only
went down in lifetime hours, but also went
up in price. When they first hit Future,
they were $36 US. Now i think they are $45?
What's up with that?
Also, Future seems to be the only supplier for
the Lumileds LED's...whats up with that too?

Also on the plus side, i use my 1watt LS almost
EVERY SINGLE day for something or another,
and would never want to go back to a standard
flashlight bulb under any circumstances
LED's are still beating bulbs by a longshot
in my opinion.
If Lumileds could get the runtime of the 5w
produce up near the 1w product then i'd surely
buy into it. I just wonder what the color
of these guys are going to be... green, purple,
red, yellow, orange, or really close to white?

Good luck with your LED circuits, and your
LED color tints and runtime hours

Al

PS. Im still pro LED's and i always will be.