| Popis: |
The publication of a new ISO standard and the increasing need to tolerance the surface quality of laser components has created renewed interest in defining surface imperfection parameters. Assessment of the performance of conventional subjective methods using reference scratches stressed the importance of an objective approach. An analysis of the distribution of intensity in the image of the simplest imperfection in the form of a single step suggest that the eye could see such a feature with height of only 0.01 of the wavelength used. Various parameters for quantifying surface imperfections are reviewed leading to the selection of radiometric obscuration. This choice is justified on the basis of ease of measurement, traceability to natural standards for line width and a good range of sensitivity. The need for further work to relate the magnitude of this parameter to eh cosmetic appearance and/or function of a system is stressed. |
