Universal-burning linear tungsten—halogen lamps

A solution to the problem of halogen separation in linear tungsten-halogen lamps burning at arbitrary angles to the horizontal is presented. Two major advances in the technology of these lamps are reported. These are an understanding of the precise physical mechanism of halogen separation, and the advent of new forms of halogen compounds which permit the use of highly reactive halogens, such as bormine and chlorine, without excessive filament damage. By combination of these two areas of research, a universal-burning lamp has been developed, and is reported here.