Adaptive Optics Rotational Design and Electro-Magnetic Actuation

Abstract

This paper presents the utilization of polymer and reflective polyester and other flexible films to fabricate deformable rotational mirrors, where the rotation is utilized to help and filter a reflected image impacted by mirror surface impurities. A self-supporting membrane is fabricated using Mylar polyester film, with a diameter of 120mm and a thickness of 1mm. Electromagnetic actuation is used in combination with a magnetic electrode array beneath the mirror membrane to deform the reflective surface and change the location of the focal point. The mechanical properties of the Mylar polyester film are such that the deflection required for focal point position is minimal, thus increasing mirror flexibility and sensitivity when controlled electromagnetically, whilst the fabrication process is simple and potentially low cost. The developed mirror in this paper consists of two similar membranes lying on top of each other, both rotating at equal speeds around the center to ensure electro-magnetic forces used for deflection are spread evenly between each reflective film sector. The developed mirror prototype functionality was successfully demonstrated when used to filter an image using rotational motion and focus an unfocused picture taken by a regular camera. Therefore, the two main features of the developed mirror are: The rotational behaviour of the mirror and its divided surface that give it the ability to filter the impact of surface impurities on the reflected image and the flexibility to concave and change focal point location while in rotation. This design can be implemented on MEMS devices that look to reduce manufacturing costs by dealing with less than perfect reflective surfaces or other example applications that aim to digitize objects (take images) to be used in virtual reality related projects.