Close

Search

Search Menu
Photonics Media Photonics Buyers' Guide Photonics EDU Photonics Spectra BioPhotonics EuroPhotonics Industrial Photonics Photonics Showcase Photonics ProdSpec Photonics Handbook
More News
SPECIAL ANNOUNCEMENT
2016 Photonics Buyers' Guide Clearance! – Use Coupon Code FC16 to save 60%!
Photonics Dictionary

narrow-angle dark-field illumination

An imaging system designed to highlight small deviations in a planar reflective object such as a mirror. The system can be used to detect minute flaws or to image faint marks that are made in the polished surface. A ringlight is positioned concentric to and close to a telecentric lens, such that the diameter of the ringlight is only slightly larger than, and in the same plane as, the entrance pupil. If the distance between the entrance pupil and the object is at least 10 times the diameter of the entrance pupil, then the lighting will be narrow-angle dark-field illumination.
Terms & Conditions Privacy Policy About Us Contact Us
back to top

Facebook Twitter Instagram LinkedIn YouTube RSS
©2016 Photonics Media
x We deliver – right to your inbox. Subscribe FREE to our newsletters.