Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2008 · 13 citations · 0 references
EngineeringMeasurementOptical TestingEducationSensor TechnologyInnovative SolutionCalibrationOptical PropertiesMirror Alignment MonitoringLargest TelescopesSegmented Primary MirrorInstrumentationElectrical EngineeringInductive Edge SensorsStructural Health MonitoringOptical SensorsMicrofabricationApplied PhysicsSensor DesignSegment EdgesOptical Sensor
The largest telescopes (ELT) involve a highly segmented primary mirror. The monitoring of the mirror shape use thousands of sensors, located on segment edges, which measure the relative piston, tip and tilt of all segments. Today, telescopes with segmented primary mirrors use capacitance-based edge sensors. Although this technology offers excellent metrological performances, its practical use is limited by the intrinsic sensitivity to humidity, dust and condensation, whose effect exceeds the requirements for future ELTs. Being specialized in both capacitive and inductive metrology, Fogale nanotech has developed a novel concept of edge sensors using the inductive technology, which does not suffer from humidity, condensation, and dust effects. Cost effective sensor with specific layout, associated electronics, demonstrated metrological performance (sub-nanometer resolution and nanometer stability) that outperforms the capacitive concept.