Flat TV - Plasma Plasma is a flat, lightweight surface covered with millions of tiny glass bubbles. Each bubble contains a gas-like substance, the plasma, and has a phosphor coating. Think of the bubbles as the pixels. Now, think of each pixel-bubble as having three sub-pixels – one red, one green and one blue. When it is time to display an image signal (RGB or video), a digitally controlled electric current flows through the flat screen, causing the plasma inside designated bubbles to give off ultraviolet rays. This light in turn causes the phosphor coatings to glow the appropriate color.