Ultraviolet (UV) Imaging for Surface Inspection
Ultraviolet (UV) imaging is beginning to emerge as a useful inspection option for industrial processes. Although it is in its infancy compared to the more established visible light or even infrared inspection processes, the drop in cost of UV cameras and controlled light sources is pushing the technology into new applications in production and research environments.
Most materials strongly absorb ultraviolet light making it easier to visualize the surface textures and topology of an object without the light penetrating into the subsurface. Fine surface structure also tends to scatter the shorter wavelengths of UV light compared to the visible spectrum. Collectively, these characteristics of ultraviolet light make it a better choice for inspection of fine surface details.
Reflected UV Imaging is not to be confused with UV-fluorescence imaging. UV reflected imaging captures ultraviolet light reflected or scattered from a surface at the same wavelength as the illuminating source. UV fluorescence imaging, on the other hand, uses ultraviolet light to excite molecules in the material inspected into a state of fluorescence in which light is re-emitted at a wavelength of lower energy and hence longer wavelengths.
The choice of UV reflected or UV fluorescence imaging of course impacts the choice of optics, lens filters, and even camera hardware. UV reflected imaging requires an ultraviolet sensitive camera with spectral sensitivity reaching down to 200nm-250nm, ultraviolet transmissive lenses, and filters to block out ambient visible light. UV fluorescence imaging does not require a ultraviolet sensitive camera or UV transmissive lenses. However, since fluorescence is typically emitted at low levels, fluorescence imaging does require a camera capable of low light detection and lens filters selected precisely for the fluorescence wavelengths imaged.
Selecting An Ultraviolet Camera and Optics
Industrial Camera Sales has partnered with Universal Optics to provide high quality UV quartz lenses to match with our ultraviolet sensitive cameras. Lenses are available for C-Mount, T-Mount, and S-Mount style cameras and boards. A unique characteristic of quartz lenses is their relatively uniform spectral transmission above 80% from 200nm through 1100nm, making these lenses an ideal choice for Ultraviolet, Visible, or Near Infrared imaging systems.
Use the image sensor size of your camera, desired working distance, and field of view to select that appropriate lens from the table below. Click on the Lend Model No. to access the product sales page and technical specifications.