Dark Field Collimated Illumination/DFC-2
This illumination is suitable for detecting the microscopically small scratches, foreign substances, soils and so on by visual inspection. It is very easy to find the above abnormalities on the surface of transparent substrate and mirror (ex. glass, lens, filter, film).
The abnormalities on the curved surface can be detected easier by transmitted light. On the other hand, in the case of inspecting flat surface, reflected light is good for detection.
