9 February 2007 Electrostatic polymer-based microdeformable mirror for adaptive optics
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Future adaptive optics (AO) systems require deformable mirrors with very challenging parameters, up to 250 000 actuators and inter-actuator spacing around 500 &mgr;m. MOEMS-based devices are promising for the development of a complete generation of new deformable mirrors. Our micro-deformable mirror (MDM) is based on an array of electrostatic actuators with attachments to a continuous mirror on top. The originality of our approach lies in the elaboration of layers made of polymer materials. Mirror layers and active actuators have been demonstrated. Based on the design of this actuator and our polymer process, realization of a complete polymer-MDM has been done using two process flows: the first involves exclusively polymer materials while the second uses SU8 polymer for structural layers and SiO2 and sol-gel for sacrificial layers. The latest shows a better capability in order to produce completely released structures. The electrostatic force provides a non-linear actuation, while AO systems are based on linear matrices operations. Then, we have developed a dedicated 14-bit electronics in order to "linearize" the actuation, using a calibration and a sixth-order polynomial fitting strategy. The response is nearly perfect over our 3×3 MDM prototype with a standard deviation of 3.5 nm; the influence function of the central actuator has been measured. First evaluation on the cross non-linarities has also been studied on OKO mirror and a simple look-up table is sufficient for determining the location of each actuator whatever the locations of the neighbor actuators. Electrostatic MDM are particularly well suited for open-loop AO applications.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Frederic Zamkotsian, Frederic Zamkotsian, Veronique Conedera, Veronique Conedera, Hugues Granier, Hugues Granier, Arnaud Liotard, Arnaud Liotard, Patrick Lanzoni, Patrick Lanzoni, Ludovic Salvagnac, Ludovic Salvagnac, Norbert Fabre, Norbert Fabre, Henri Camon, Henri Camon, } "Electrostatic polymer-based microdeformable mirror for adaptive optics", Proc. SPIE 6467, MEMS Adaptive Optics, 64670P (9 February 2007); doi: 10.1117/12.705256; https://doi.org/10.1117/12.705256

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