Fem modelling of an electro-optical micro-shutter

The goal of this paper is to present a numerical tool which has been designed for studies of electro-optical micro-shutters. After a brief introduction on recent works about shutters in the Fiat Research Center, the authors describe the FEM modelling of a micro-shutter device. The next section presents the numerical methodology used for this electro-mechanical coupled study. The main simplification concerns the plane strain hypothesis to perform a two-dimensional modelling. The coupled study is made in two steps: at first, an electrostatic analysis is computed to determine the force acting on the flexible conductor; then a structural analysis is performed to obtain the deformation which will be used to remesh the electrostatic model. The next section shows different threshold voltages obtained in function of the petal and dielectric layer thickness. These results indicate how threshold voltages are very dependant on these geometrical parameters. In conclusion, the authors explain the interest of this numerical tool for the prediction of optimum parameters before designing a micro-shutter device. At last a discussion is shown about the plane strain hypothesis and the necessity to design a three-dimensional model.