Homebrew PCBs

David Griffith wrote:
> Someone said that no professional board shops use ultraviolet LEDs.  Why 
> is that?
> 

An LED is a point source of light. Fluorescent tubes emit a more-or-less 
constant intensity of fairly diffused UV along almost their entire length.

Thus it's easier to calculate the exposure for the boards, then once 
you've got everything set up, it's easily repeatable. On top of that, 
you don't get brightness peaks and troughs as you move around the 
exposure platform (glass plate or whatever).

-- 
Phil.
ygroups@...
http://www.philpem.me.uk/