Fluorine-cycle incandescent lamps

Tungsten-halogen incandescent lamps containing either bromine or iodine as the halogen are commercially available and exhibit a life or light output superior to that of nonhalogen lamps. To further increase the life of this kind of lamp, fluorine was tried as the halogen. By adding bromotrifluoromethane (CBrF3) to the fill gas, lamp life more than twice that of lamps containing bromine alone was achieved. To avoid deleterious side effects of the fluorine cycle, a small amount of oxygen is required in the lamp. This oxygen can be supplied simply by omitting some of the processing steps normally used to remove residual oxygen.