DIN ISO 14997:2013-08

This standard describes the physical principles and specifies the practical means for the implementation of methods for measuring surface imperfections. The methods evaluate the surface areas obscured or affected by the imperfections. This standard was developed in response to the demand for test methods for surface imperfections that are objective and permit fast assessment of component quality. Existing standards have been assessed and found to be too variable in use to satisfy the current requirements of optical industry. Surface imperfections, such as digs and scratches, arise from localized damage during or after manufacture. They can be visible as a result of the light they scatter, giving rise to a false impression of poor quality. Alternatively, this light can appear as unwanted veiling glare (stray radiation) in an image plane, or it can lead to a degradation in signal quality at an image sensor. Imperfections can also provide centres of stress, eventually leading to failure of components exposed to high laser radiation power/energy densities. Since modern methods of surface examination are capable of atomic resolution, no surface is likely to be found totally free of localized imperfections. Most surfaces produced are satisfactory for their intended purpose, but a small proportion can have suffered obvious damage and will be reworked or regarded as unacceptable. This can leave some components which, although slightly damaged, can still be found acceptable, when tested, depending on the level of acceptability of surface imperfections requested by the customer and specified on drawings in ISO 10110-7. This International Standard describes how these methods are implemented. This International Standard ISO14997:2011 has been prepared by ISO/TC 172 "Optics and photonics", Subcommittee SC 1 "Fundamental Standards" the secretariat of which is held by DIN. Working Committee "Grundnormen der Optik" ("Fundamental standards for optics") of the Standards Committee Optics and Precision Mechanics (NAFuO) at DIN is responsible for the preparation of this standard.