Active focusing device based on MOEMS technology

摘要

A MEMS based device for active focus control is presented. The concept has been developed using coupled field FEM simulation. The focus length is adjusted by a reflective membrane which is electro-statically deformed. Using a special ring shaped counter electrode and an optimized weak membrane suspension, a perfect parabolic shape of the deformed membrane is obtained over a very large diameter at reasonable low driving voltages. The counter electrode is part of the chip package which simplifies the fabrication process. Using SOI-technology, the realization of stress free membranes with a diameter up to 10 mm has been proven. The device can be used in active optical applications where large numerical apertures are needed. Potential applications are e.g. confocal microscopy or scanning applications for focus control. In this paper, detailed results of the design optimization process are presented.