It was reported that a plasma display panel with hump electrode in the long gap has improved discharge characteristics such as luminous efficacy, addressing jitter than long gap electrode structure. In this paper, as an extended study of previous work, we report properties of long gap discharge with hump electrode for various Xe concentration ratio in a Ne-Xe binary gas mixture. Due to the hump electrodes between long gap, discharge voltage is reduced by 20-30 V and high luminous efficacy is obtained at low voltages in high Xe percentage. For more detailed observation of discharge, ICCD images of infrared light emission from excited Xe in discharge cell are taken. The results show that the discharge is initiated between short gap of hump electrodes and the main part of the discharge is maintained between long gap electrodes. In addition, 3-dimensional simulation study shows that hump electrode shape has higher number of excited Xe and Xe(2) than the conventional one. This is well correlated with the experimental result showing higher luminance in the hump structure. (C) 2010 Elsevier B.V. All rights reserved.