What is UV Light?

Ultraviolet light is a particular portion of the light spectrum, typically considered to be in the wavelength range from 200 nm (nanometers) to 400 nm. Light in this spectral range has many important uses including water purification, semiconductor lithography, sun tanning and, of course, adhesive curing.

Since ultraviolet light falls below the visible portion of the light spectrum, we cannot see pure UV light. Special equipment—a radiometer—is required to measure the intensity of UV light. The intensity of light falling on a surface is measured in milliwatts per square centimeter (mW/cm2), or power (mW) per unit area (cm2).