> =A0I put before the LED guru's eyes the following to ruminate and
> disseminate upon.
>
> http://www.epistar.com.tw/
>
> Epistar say they have produced a 110lm/W for 1W and 3W warm white
> LED's. According to them the 1W offering has a CRI (hmm some sort of
> index I suspect) of 90 @ 15v the CCT (I know that one) is 3000K

CRI =3D color rendering index =3D quality that colours are rendered in
compared to "true" white.
80 =3D Reasonably good.
90 =3D extremely good.

110/lm/W is very good for warm whites, which are down somewhat on
"daylight white".

Note in the Nichia catalog that I referred to here a few days ago, at
power levels of only about 150 mW:

NSPLR70CS-K1 =3D warm white =3D 116 lm/W typical
NSPWR70CS-K1 =3D daylight white =3D 129 lm/W typical.

In fact the latter is even better in practice than in the catalog as
Vf in practice clusters very tightly around 2.95 V, giving lm/W of
more like 135 /m/W - and more again at lower currents. (Looking at one
at a metre or so at 50 mA hurts the eyes).

Also note that the Epistar product is probably 'not quite available
yet', whereas the Nichia parts have been on the market for about a
year.

Epistar do seem to be trying hard in that they are using more LED
colours and perhaps more phosphors than the norm.


     Russell

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