ABSTRACT
Due to the flat irradiation angle used, the scattered-light measuring procedure provides the possibility of fading-out surface structures, and of illuminating only particles on the surface. With this method, all types of technical surfaces can be examined for particulate contamination, independent of their surface roughness. Due to the detection principle and the technical set-up of the light-optical microscope, the ability to optimize scattered light detection exists, should an additional grazing-angle illumination source be used. This approach combines the advantages of the light-optical microscope, with bright field and dark field illumination, with the possibility of adapting scattered light detection when examining extremely textured technical surfaces. Thus all types of technical surfaces may be examined for particulate contamination. Particle concentrations of up to 8 particles/ square centimeter can be detected with sufficient accuracy using 400 measuring points. The accuracy achieved using 400 measuring points is perfectly adequate when examining a surface for particulate cleanliness, regardless of the detected particle concentration.
