[sdiy] Re: Vactrol (opt align) VCF rev 2: help needed

[mirwin at qouest.net]

Or... use an ultraviolet LED (or several) to excite a phosphor-coated 
plate (short or long-persistence)... give a nice even  diffuse 
illumination, without requiring HT supply.

The white LED's use a phosphor-coated blue-emitting chip and emit 
diffuse light... these might be good by themselves... check the polar 
graphs in the spec sheets.
Cheers, Mike