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 th e maximum sustain voltages, the minimum sustain voltages, and the volt age margins for 100% helium, 100% xenon, and for 2% xenon in helium an d a 400 torr pressure (p) and a gap (L) of 100 mu m. The multipulse si mulations describe the growth in mall voltage at the so called ON volt age and the decay in wall voltage at the so-called OFF voltage. For sq uare wave forms, the ON voltage is the voltage at which a pixel attain s to a stable operation in which a discharge occurs in each succeeding pulse and the wall voltage equal to the applied voltage. The OFF volt age 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 sim ulations are almost identical to the values obtained from the wall vol tage transfer curve method. In the helium-xenon Penning mixture, the i onization rate for xenon ground state increases dramatically compared to its ionization rate in pure xenon due to the modification in the el ectron velocity distribution function in the mixture. This feature pro vides enhanced volumetric ionization in the discharge and hence a rapi d growth rate of the wall voltage which is desirable for a sharp trans ition from OFF to ON in a pixel.