Abstract: A scanning flat back light source for use with light valve devices such as liquid crystal displays. It is formed by an array of parallel fluorescent tubes with fluorescent layers therein. One end of each tube is provided with an electrode and the other end connected together through a transverse chamber to form a single vacuum unit. When electrical potential is applied across electrodes in two different chambers, the two chambers and the portion of the transverse chamber connecting the two chambers form a fluorescent lamp where gas discharge produces ultraviolet light that causes a fluorescent layer on the inside walls of the tubes to produce single-color or multi-color light.