22 Jan
2003
22 Jan
'03
10:36 a.m.
Doug Jackson wrote:
A UV LED?????
[...]
I was aware that we have White, and blue (Through
Phospor, and funky
doping), but these UV devices are new to me...
Blue LEDs don't require any phosphor. The phosphors are used to get
*other* colors from blue or UV LEDs, such as white. Agilent made some
really nice white LEDs that didn't have the remaining blue tint of
the common ones, but they were expensive and no one wanted to pay
the premium, so they've been discontinued.
The earliest blue LEDs (Silicon Carbide) had very low output, so RGB LEDs
needed two blue dice to one each red and green to get decent matching.
However, so much R&D has been done to improve them that now blue LEDs
(gallium nitride) are now the *most* efficient, at least in the visible
spectrum.