VLT 4LGSF OTA L2 lens measurement on NANOMEFOS

VLT 4LGSF OTA L2 lens measurement on NANOMEFOS Aspherical and freeform optics enable significant improvements in the performance of optical instruments for the semiconductor industry, medical applications, space, astronomy and other scientific research fields. Freeform optics results in fewer optical aberrations, and considerably reduces the number of components needed, which leads to better optical transmission, smaller dimensions and a lower instrument mass. Innovative designs are also made possible. Classical methods of measuring are not suitable for measuring these complex, asymmetric and strongly curved surfaces. To solve this problem TNO developed NANOMEFOS (Nanometer Accuracy Non-contact Measurement of Freeform Optical Surfaces), a device that can measure large freeform optics quickly and without contact at a measurement uncertainty of just a few nanometres. NANOMEFOS signifies a revolution for the manufacture of freeform optics. The object to be measured (which may also have non-rotational symmetry or an interrupted surface) is placed on a continually rotating, air-bearing spindle over which an optical probe moves enabling very high scanning speeds (up to 1.5 m/s). The position of the probe and the spindle are measured by an interferometry system and capacitive sensors relative to a silicon carbide metrology frame, thereby compensating the measurements for drift as well as static and dynamic position errors. More info at: www.tno.nl/vlt4lgsf and www.tno.nl/nanomefos