I did some development a while back for a customer who wanted to sell
advertising stuff with EL lighting.  I learned some things y'all may find
interesting:

1.  There are several different kinds of phosphors, and many varieties of
each.  Color, voltage and drive frequency vary.
2.  Voltages range from 30-40 VAC to as high as 800 VAC.
3.  Higher frequencies tend to make the colors more blue, lower
frequencies, more green.  You can run some phosphors from 60 to as high
as 1000 Hz.
4.  The lamps look like lossy (resistive) capacitors.  Thus the current,
power dissipation, and light output are closely related to voltage and
frequency.
5.  Phosphors degrade with time, and faster if you use them.  The harder
you drive them the shorter the life.
6.  Phosphors degrade with moisture.  That's why most sheets should not
be cut (it destroys the edge seal).  There are some materials that have
micro-encapsulated phosphors.  These can easily be cut without affecting
the reliability.
7.  Attaching electrodes may be the most problematic item for hobbyists.
The thing is basically a capacitor with phosphor in the dielectric.  The
back plate can be heavy and opaque, but the front plate needs to be
transparent.  I don't know a lot about how they do it, but it ends up
being a very thin metallic layer with a protective insulator over it.

Hope this is helpful, or at least enlightening.  Time for some
ZZZZZ's....


Don