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 the 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 a 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.