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[APD] LEDs and color temperature
On Sat, 3 Jan 2004 18:14:35 -0500, Ivo Busko <busko at stsci_edu> wrote:
That link didn't work for me, but I have another one (that probably won't
"S. Hieber" <shieber at yahoo_com> wrote:
plants? I'd like to hear about that lamp, energy
efficiency, light dispersion, spectral output, etc.
Long time ago I posted something about LEDs (see
As far as I can tell, LEDs are not more efficient than
regular incandescent bulbs. And won't become better than
fluorescents are nowadays (about 30% efficiency). IMHO,
not good enough to justify the expense.
I'm not suggesting the 'organic LED's' of the article are worth waiting
for, but there was some interesting information. Specifically, it said
that normal (non-white) LED's produced light at only one wavelength. I
assume, it would therefore be expensive to make a white LED, and so it
would be better to use a large array of primarily red and blue LED's whose
wavelengths are in the absorbtion range of photosynthesis (does
photosynthesis occur over a wide range or a few discrete wavelengths?).
I'm not sure if the plants would appear well 'illuminated' if you just
used red and blue, though, because there would be no green light for you
to see them by! (Incidentally the organic LED described would be an
excellent all-round light source as it would produce a wide spectrum like
an incandescent but be more efficient?)
This link has a comparison of lumen/watt efficiency.
It also states that LED's are a horrendously inefficient way to light
larger objects (although it also says a 100W light bulb would still be
marginally less efficient than LED's?).
Happy Self-Confessed Armchair Aquarist (until I get my own room), Andrew
thefish at theabyssalplain_freeserve.co.uk
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