Ultraviolet light is most commonly used to cause materials such as inks or glues to fluoresce for identification or bonding integrity inspection. It also easily scatters off very small surface features such as scratches more so than longer wavelengths.

	Visible light illuminates both the PCB features as well as foreign matter so they are difficult to distinguish.	UV light does scatters from the top layer of the board illuminates only the foreign particle but not the PCB trace pattern.
	Uniformly illuminating the bottom of can is very difficult to do with any wavelength of light.	UV light can be used to make an invisible ink fluoresce brightly for easy detecting that doesn't require even illumination of the background.
	Visible light does not illuminate the authenticity code used to identify high value items from imitations.	UV light shows the invisible bar code used to authenticate the merchandise origins.
	Visible light penetrates the mat and does not provide sufficient contrast.	UV light reflects off the surfaces with high internal residual stress for reliable detection.

*The sample works used in this catalog were purchased and processed by CCS, and they do not represent their original qualities and performances.