Nichia offers a Superflux LED with impressive luminous efficacy (160 lm/W)
and they may be cheap enough in volume, but I can't find much pricing info.

http://www.nichia.com/specification/led_09/NSPWR70CSS-K1-E.pdf

http://www.leds.de/Bestseller/Nichia-Superflux-LED-weiss-25lm-80-RAIJIN-NSPWR70CSS-K1.html?redirected=1

_____________

The current limited availability of that part is why I'm asking. Things will
change, but at the moment it's tight. I know the price, but if I told you
I'd have to kill myself (or Nichia would :-).) It would be permissible to
say that $/Watt it's nowhere near as good as its somewhat bigger brothers
from all major manufacturers, but in its class it's incomparable. Sadly.

The 160 l/W is at 20 or 30 mA and drops off somewhat when run at its full
rated 50 mA. At 50 mA it has a 15,000 hour life to 70% output. A very nice
little LED.

The Cree CP41B-WES and WGS (60 degrees and 90 degrees) are OK but not in the
same class.  The top P0 flux bin gives 8.7 minimum, 11 maximum lumen or
about 100 lumen/Watt.

     Russell


2010/1/14 Michael Rigby-Jones <Michael.Rigby-Jones@oclaro.com>

>
>
> > -----Original Message-----
> > From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
> > Of Russell McMahon
> > Sent: 13 January 2010 10:26
> > To: Microcontroller discussion list - Public.
> > Subject: [EE]:: LED suggestions sought
> >
> > I'm in need short term of a high performance small LED.
> > Cost sensitive so needs to be lowest price while meeting the minimum
> > specs..
> > There are numerous LEDs available which meet the specs while running
> > at a fraction of their rated capacity. Technically that's fine BUT
> > cost is unacceptable.
> > (eg Luxeon Rebel, Cree XR-xxxr, Osram xxx Dragon, ...)
> >
> > Osram LUW-CN5M is close to OK - not what I'd use if I can help for
> > various reasons.
> >
> > ____________
> >
> > MUST have following specs.
> >
> > White. Prefer cool White   (around CIE1931 0.31, 0.31) but Anything
> > considered.
> > 40 mA operation minimum.  (Max not much over this due to cost)
> > 15,000 hour operation to 70% or better
> > Highest possible lumen/Watt but really want > 75 l/W at 40 mA.
> > Ideally a P4 package through hole mount (such as eg Cree CP41B) BUT
> > any mount considered.
> > Radiation angle preferred around 80 degrees, As low as 60 degrees may
> > be OK. Over 90 degrees may be OK but less desired.
> >
> > Lowest cost desired. Ideally WELL under $US0.75 in good volumes.
> >
> > Reputable manufacturer, online data sheet.
> >
> > Finders fee by no means guaranteed but an especially good find may
> > qualify or something nominal.
> > NOTE MUST meet above specs.
> > ________
> >
> >
> > 2 or 3 x 5mm LEDs may apply as a group IF specs otherwise met.
>
>
>
>
> Regards
>
> Mike
>
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