text: Since development of the aluminium gallium nitride LED in the early 2000s, UV LED technology has seen sustained growth in the UV curing marketplace. Generating energy most efficiently in the 365-405 nm UVA wavelengths, continued technological advances, have allowed for improved electrical efficiency of UV LEDs as well as significant increases in output. UV LED lamps generate high energy directed to a specific area which strengthen the uniformity. Benefiting from lower-temperature operation and the lack of hazardous mercury, UV LEDs have replaced medium-pressure lamps in many applications. Major limitations include difficulties in designing optics for curing on complex three-dimensional objects, and poor efficiency at generating lower-wavelength energy, though development work continues.