There are tungsten vapor, iodine vapor, tungsten iodide gas and inert gas in the iodine tungsten lamp.

An iodine tungsten lamp is a kind of high-efficiency lighting fixture, which is generally composed of tungsten wire and quartz glass shell. Because of its small size and high internal temperature, the glass shell will undergo a cycle of "melting-cooling-solid reheating" after use. If there is an impurity attached to the bulb shell and the surface treatment is not carried out in time, the atomic arrangement of quartz glass will change at high temperatures, causing the surface to crystallize and lose its transparency. This phenomenon is called devitrification.

The tungsten filament of a tungsten iodine lamp is a conductor and can radiate visible light. A tungsten iodine lamp is a new type of electric light source, the main components are the internal tungsten filament and the external glass shell. Under the action of electric current, the spiral tungsten filament continuously gathers heat, making the temperature of the filament reach over 2000℃. Microscopically, the tungsten atom's electrons outside the nucleus are excited by heat to a high-energy state, to maintain stability and fall back to a low-energy state, the energy difference in the form of photons released, macroscopically visible luminescence phenomenon.

Quartz glass can be used as bulb shell of iodine tungsten lamp.Iodine tungsten lamp is one of the first choice products in green lighting engineering in China. It has the characteristics of high light efficiency, small volume and energy saving, and is suitable for the design and shape of various lamps and lanterns. It is widely used in lighting field.