Metal halogen lamp, also known as metal halide lamp, is ultraviolet lamp that developed from the combination of high pressure mercury lamp and metal halide. As with the difference of the types of metal halide added into the lamps, the spectrum distributions of the lamps and their usage are different correspondingly. Once added with GaI3, the spectral energy of the lamp increases 403nm or 417nm and the lamp also turns into Iodine gallium light, copy light or exposure lamp.