The principle of iodine-tungsten lamp is similar to that of incandescent lamp except that it is flushed with iodine vapor. The iodine vapor has a property that it is at low temperature (relatively) with tungsten and at high temperature it decomposes, so that it is located in the lamp tube other In part, the tungsten has been sublimated and removed, and then decomposed on the filament, so that the filament will not be quickly burned due to high temperatures.
Compared with ordinary incandescent lamps, the iodine tungsten lamp greatly reduces the evaporation of tungsten, prolongs the service life, and increases the working temperature and the luminous efficiency of the iodine tungsten lamp. The average service life of an ordinary incandescent lamp is 1,000 hours. The iodine tungsten lamp is half as long as it is and the luminous efficiency is increased by 30%. From a standpoint, iodine-tungsten lamps appear particularly small and exquisite. Similarly with a 500 watt bulb, the volume of iodine-tungsten lamps is only 1% of that of incandescent lamps. In addition to iodine, the glass bulb is filled with inert gas, small and strong, and the inflation pressure is as high as 1.5 to 10 atmospheres. According to different uses, iodine tungsten lamps can be divided into several types: Some iodine tungsten lamps can emit a large number of invisible infrared, high thermal efficiency, is the ideal heat source for heating and drying. Some iodine tungsten lamps have large power and can radiate a large amount of light energy. They are suitable for lighting in large workshops, squares, stadiums, airports, and ports.
Some iodine tungsten lamps are light sources for photojournalism, color photolithography, and cinematography and screening. Their high power, small size and light weight are their main advantages. In some laser devices, iodine tungsten lamps can also be used as light pumps. Tungsten-tungsten lamps have high luminous efficacy, high brightness, and compact structure. These are exactly the strengths of transportation vehicle lighting. Now trains, especially spotlights, fog lamps, and main headlights on automobiles, are gradually changing to iodine-tungsten lamps. The most common iodine tungsten lamp has a slender body like a pen. The main body of the lamp is a quartz tube with a diameter of 10 to 12 mm and a softening point of up to 1700 °C. The filaments support the filaments with a support ring at regular intervals. The rectangular flat blocks at both ends of the filaments are sealed to ensure that they are electrically conductive and do not leak gas.