Tolerances for surface form deviations

The evolution of the old standard DIN 3140 for the tolerances of surface form deviations to the actual standard ISO 10110-5 introduces a more complex description of the form deviations and their tolerances. The drawing standard ISO 10110-5 is accompanied by the measurement standard ISO 14999-4, that complements the old test glass measurements by interferometric test methods. The different types of surface deformations have different impact on the performance of an optical system, and the selected tolerances must limit the image degradation within the specified limits. For some specific applications the most appropriate description of the relevant surface deformation is not yet foreseen in the actual standard, but future versions of the standard might include reasonable extensions.