The Plasma Display was one of the first displays used in portable computers. Most plasma displays glow with an orange colour. They work by ionizing neon gas. As the voltage over the gas rises over ca. 100V the process starts. The optimum operating voltage is about 200V. This type of display has a good contrast (about 30:1) but the light intensity is low (30-35cd/m2).
The last few years a new type of plasma display has been available. This display is built up of many enclosed cells arranged in a grid pattern. Each of these cells contain a gas mix that emit ultraviolet light when ionized. This UV light in turn makes a phosphor light up. By arranging these cells in a RGB-triplet, a colour image can be produced.
When the gas has been 'lighted', it can be sustained by a lower voltage. This means that by having an extra electrode in each cell and let it supply a sustained voltage the cell can continue to emit light until the next refresh cycle. This means that you have a active screen (similar to Active Matrix LCDs) but without the need for thin film transistors.
Though this screen type is relatively thin it is also heavy so a wall might have to be reenforced to take the weight.