LED is used as indicator lamps in many devices, and is increasingly used for lighting. LED is available across the visible, ultraviolet and infrared wavelengths, with very high brightness. UV LED is one kind of LED, which is short for ultra-violet light emitting diode. It is featured with portable, low cost, environment friendly, lower energy consumption, longer lifetime, improved robustness, smaller size, faster switching, and greater durability and reliability. UV LED is widely used as replacements for aviation lighting, automotive lighting (particularly brake lamps, turn signals and indicators) as well as in traffic signals. The compact size, the possibility of narrow bandwidth, switching speed, and extreme reliability of UV LED has allowed new text and video displays and sensors to be developed, while their high switching rates are also useful in advanced communications technology.