AC PDP with MgO protective layer coated with the optimum evaporation rate of 5 angstrom/s can generate more enhanced efficiency through the vacuum in-line sealing process. However, the optimized process conditions still require the optimum driving scheme on the ramp-up and ramp-down slope of the reset waveform for enhancing discharging efficiency. For the in-situ vacuum sealed PDP with the optimum evaporation rate of MgO protective layer, the delay times of address discharge were investigated with various slopes of ramp waveforms during a reset ramp-up and ramp-down period. And the optimal driving scheme was also obtained. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.