UV stands for Ultra-Violet Ray with the range of wavelength from 200nm to 450nm. Based on the wavelength, it is grouped into the followings：

UVA 320nm～400nm
UVB 275nm～320nm
UVC 200nm～275nm
Vacuum 100nm～200nm

UV lamp is the lamp in which gas discharges light, grouping into arc light and glow discharging. How does the UV lamp work? An amount of mercury is put into the glass pipe; and both of the electrodes are provided with high voltage, the voltage difference between the two ends could lead to discharge electricity, bringing UV radiation.