The NANOMEFOS non-contact measurement machine for freeform optics

• Published in: Precision engineering Vol. 35; no. 4; pp. 607 - 624
• Main Authors: Henselmans, R., Cacace, L.A., Kramer, G.F.Y., Rosielle, P.C.J.N., Steinbuch, M.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.10.2011; Elsevier
• Subjects: Applied sciences; Asphere; Bearings, bushings, rolling bearings; Design engineering; Drives; Exact sciences and technology; Freeform optics; Industrial metrology. Testing; Measurement machine; Mechanical engineering. Machine design; Metrology; Metrology frame; Nanocomposites; Nanomaterials; NANOMEFOS; Nanostructure; Non-contact; Optical components; Precision engineering, watch making; Silicon carbide; Weight reduction; Non-contact; Asphere; Freeform optics; NANOMEFOS; Measurement machine; Metrology frame; Measuring machine; Uncertainty; Testing machine; Position control; Free form; Precision engineering; High precision; Optics; Surface metrology; Aspheric surface; Direct method; Nanometer scale; Uncertain system; Displacement measurement; Optical component; Parallel configuration; Gas bearing; Experimental study; Telemetry; Optical measurement; Repeatability; Silicon carbide; Non contact measurement
• ISSN: 0141-6359; 1873-2372
• DOI: 10.1016/j.precisioneng.2011.04.004

► A non-contact measurement machine for freeform optics has been developed. ► The machine design, consisting of a motion system, metrology system and non-contact probe is shown. ► Preliminary performance validation on aspherical and freeform surfaces is demonstrated. Aspherical and freeform optics are applied to reduce geometrical aberrations as well as to reduce the required number of components, the size and the weight of the system. To measure these optical components with nanometre level uncertainty is a challenge. The NANOMEFOS machine was developed to provide suitable metrology (high accuracy, universal, non-contact, large measurement volume and short measurement time) for use during manufacturing of these surfaces. This paper describes the design, realization and testing of this machine. In particular it describes the design and testing of the air-bearing motion system with parallel stage configuration, and the separate metrology system with Silicon Carbide metrology frame and an interferometry system for direct displacement measurement of the optical probe. Preliminary validation measurements demonstrate the nanometer level repeatability for freeform surface measurement.