Gas-plasma displays works by applying an electrical current to excite a gas. This type of display was first seen in the 1960's at the University of Illinois with the Plato terminal. The display emits an orange-red light because of the type of gas and the voltage applied. The problems with gas plasma is the amount of power the display uses.
A gas-plasma screen consists of a grid of cells each filled with a tiny amount of gas, usually neon gas. Each cell has electrodes on each side, and when a high voltage is applied across the electrodes, the neon gas activates and begins to emit an orange-red light.