TNO Industrie en Techniek
|Source:||Burge, J.H.Fähnle, O.W.Williamson, R., Optical Manufacturing and Testing VIII, 4 August 2009 through 5 August 2009, San Diego, CA, 7426|
|Proceedings of SPIE - The International Society for Optical Engineering|
Instruments · Asphere · Freeform · Measurement · Metrology · NANOMEFOS · Non-contact · Optics · Asphere · Freeform · Metrology · NANOMEFOS · Non-contact · Computer software · Optical systems · Probes · Surface measurement · Uncertainty analysis · Measurements
Applying aspherical and freeform optics in high-end optical systems can improve system performance while decreasing the system mass, size and number of required components. The NANOMEFOS measurement machine is capable of universal non-contact and fast measurement of aspherical and freeform optics up to Ø500 mm, with an uncertainty of 30 nm (2σ). In this machine, the surface is placed on a continuously rotating air bearing spindle, while a specially developed optical probe is positioned over it by a motion system. A separate metrology system measures the probe and product position relative to a metrology frame. The prototype realization, including custom electronics and software, has been completed. The noise level at standstill is 0.88 nm rms. A reference flat was measured with 13 μm and 0.73 mm tilt. Both measurements show an rms flatness of about 8 nm rms, which correspond to the NMi measurement. A hemisphere has also been measured up to 50° slope, and placed 0.2 mm eccentric on the spindle. These measurements reproduce to about 5 nm rms. Calibration and software are currently being improved and the machine is applied in TNO aspherical and freeform optics production. © 2009 SPIE.