Auto halogen headlight bulb, referred to as halogen bulbs or halogen lamps, also known as tungsten halogen bulbs, quartz bulbs, are a variant of incandescent lamps. The principle is to inject halogen gas such as iodine or bromine into the bulb. At high temperature, the sublimated tungsten wire and the halogen chemically act, and the cooled tungsten will re-solidify on the tungsten wire to form a balanced cycle to avoid premature rupture of the tungsten wire. Therefore, halogen bulbs are longer than incandescent lamps.

Auto halogen headlight bulb can also operate at higher temperatures than ordinary incandescent lamps, and they are brighter and more efficient. However, at this temperature, ordinary glass may soften, so halogen bulbs need to use quartz glass with a higher melting point. Since quartz glass does not block ultraviolet light, this halogen bulb usually requires an additional UV filter. Halogen lamps are commonly used in applications where centralized illumination is required, for CNC machine tools, rolling mills, lathes, turning centers and metalworking machines, automotive headlights, and in public places such as homes, offices, and office buildings.