M.Sc Thesis

M.Sc StudentNaftali Matan
SubjectTowards a Linear Response of Vertical Comb-Drive
DepartmentDepartment of Mechanical Engineering
Supervisor PROF. David Elata


In this study the electromechanical response of tilting micromirrors is investigated. Tilting micromirrors are used in optical cross-connect applications to redirect a beam of light that may emanate from one of several sources, and is to be reflected onto one of several targets. In such applications accurate angular positioning is essential. A high accuracy of angular positioning is easier to achieve in a micromirror with a linear electromechanical response. This motivated the use of electrostatic Vertical Comb-Drive (VCD) actuators in micromirror devices. However, in this work it is shown that current VCD actuators have a nonlinear response due to the motion induced in secondary degrees of freedom. In this work, a novel design of a VCD actuator is presented in which the motion induced in secondary degrees of freedom is eliminated. The resulting electromechanical response of the new design is far more linear relative to previous designs. Several test devices of the novel VCD actuator were fabricated using SOI technology. The actuators were micromachined from a single layer, and vertical staggering of the stators was mechanically implemented after the fabrication. The electromechanical response of these devices was experimentally measured. These measurements are in good agreement with model predictions, and demonstrate a linear relation between the driving voltage and the angular position.