One-dimensional single and multipulse simulations of the ON/OFF voltages and the bistable margin for He, Xe, and He/Xe filled plasma display pixels

A one-dimensional plasma model developed for ac plasma display pixels is used to perform multipulse and single-pulse simulations to model the maximum sustain voltages, the minimum sustain voltages, and the voltage margins for 100% helium, 100% xenon, and for 2% xenon in helium and a 400 torr pressure (p) and a gap (L) of 100 mu m. The multipulse simulations describe the growth in mall voltage at the so called ON voltage and the decay in wall voltage at the so-called OFF voltage. For square wave forms, the ON voltage is the voltage at which a pixel attains to a stable operation in which a discharge occurs in each succeeding pulse and the wall voltage equal to the applied voltage. The OFF voltage is the voltage at which a pixel that is ON goes off and no further discharges occur. Experimental data for helium show the hysteresis in the discharge current observed when the voltage is increased to turn ON pixels and then reduced to turn OFF pixels in a panel. Simulations which match the helium data are also shown. The difference between the ON and OFF voltages defines the bistable margin. For the helium-xenon Penning mixture, the ON and OFF voltages determined by multipulse simulations are almost identical to the values obtained from the wall voltage transfer curve method. In the helium-xenon Penning mixture, the ionization rate for xenon ground state increases dramatically compared to its ionization rate in pure xenon due to the modification in the electron velocity distribution function in the mixture. This feature provides enhanced volumetric ionization in the discharge and hence a rapid growth rate of the wall voltage which is desirable for a sharp transition from OFF to ON in a pixel.