Things are definitely improving with this technology!

I still suspect, as the article in the link I pointed out (another post) the
LED manufacturers are cheating the measurments a bit as they don't include
ballast energy (they can't as they don't know the circuit) and they don't
include the losses of the lens and/or filter and as you article describes,
the input power vs output power.

Thanx!


"Don Klipstein" wrote in message
...
Yes. The usual white LEDs have blue-emitting chips coated by a phosphor
that absorbs some-most of the blue light and converts it to a
yellow/yellowish broad band whose spectral content typically covers
mid-green to mid-red. Some of the blue light is not absorbed but passes
through the phosphor, to mix with the yellow/yellowish light so that you
get white light.

Nowadays, some of these blue chips used for white LEDs are achieving
around 40-50% efficiency. The most efficient white LED on the market that
I am aware of, Nichia NSPWR70CSS-K1 at 20 mA, is a goodly 40% efficient
even after losses of the phosphor. At 20 mA, it is supposed to typically
achieve 150 lumens/watt.

- Don Klipstein )




In article , Josepi wrote:
How can the efficiency of a white LED be higher than it's constituent
LEDs?
Is this due to phosphour screens used?