Hi,
I agree with Rich’s list of advantages, but of course there
are also some limitations to take into account, at least in my limited
experience.
Directly coupled LEDs don’t have the same illumination
homogeneity as the latest generation of liquid light guide-coupled lamps. If
you don’t adjust the condensor lens correctly, you can see the structure
of the LED in your image. Of course you also have that problem with a directly
attached lamp, and I guess it would be eliminated by using a light guide with a
LEDs.
LEDS are not strictly monochromatic but have emission bands composed
of a set of transitions. When I was a student, one exercise we were asked to do
was to dip LEDs in liquid nitrogen, to get narrower bands, and analyze their spectra
and to figure out what semiconductors and doping had been used in their
construction... Unlike when you use a semiconductor laser, you may still need
to use excitation filters with a LED.
best regards,
Emmanuel
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