How EL Lights work ?

Electroluminescent (EL) devices are actually lamps. They emit light, but they are unlike any traditional lamp. Instead of creating light by heating a filament - as in an incandescent light bulb - or by charging a gas field - as in a fluorescent or neon tube, EL relies on phosphorescent materials which glow when exposed to a small electrical current. El lamps are cool, low power and emit a soft light without any irritating glare. They are invariably very thin, almost like ribbons or sheets of paper, and they can be produced in a variety of colors. The source of light is a phosphorous mixture which is spread onto a transparent, conductive ITO (indium tin oxide) film and then covered with another thin sheet of conductive material.
The color produced by an EL panel can be altered by changing the frequency of the voltage supplied to it and/or the amplitude of the voltage. It all depends on who manufactured the panel, its size and the type of inverter