High-efficiency and high-luminance are obtained at the transition from Townsend discharge to normal glow discharge, i.e., at subnormal glow discharge mode. Also found is that efficiency increases with shorter pulse duration and is inversely proportional to the mean discharge current. On the country, luminance increases by shortening pulse duration and has a maximum. Other optical and electrical characteristics are presented. Experiments are carried out with short pulsed voltage ranging from 20 to 1000 ns, and with Xe and Ne+Xe (2%) gases to excite phosphors for color display.