Light emission of electroluminescent lamps under different operating conditions

Electroluminescent (EL) lamps are flat solid-state ac driven devices in which light is generated by impact excitation to optical energies of luminescent centers in a Mn-, Cu- or Tb doped ZnS phosphor layer by high-energy electrons and radiant decay to ground state of these luminescent centers. They are useful in applications which require diffuse low level uniform illumination. This paper presents measurements of light emission and related spectra of EL lamps as function of operation frequency and sinusoidal voltage amplitude. The excitation of other voltage waveforms is also analyzed and parameters of the equivalent electrical circuit are presented.