Analysis, design and characterisation of comb-actuated MEMS micro-mirror for raster and Lissajous scanning

Abstract

This dissertation focuses on the simulation, characterisation and design of MEMS scanning micro-mirrors intended for micro-display applications such as pico-projectors and head-up displays in vehicular systems. An insight to the architecture and device operation behind MEMS scanning micromirrors is given, highlighting the requirements of these devices whilst considering the applications these types of devices are implemented for. The fabrication processes carried out to manufacture such devices are discussed, whilst keeping in mind the advantages and disadvantages behind the actuation principles that are used to actuate the micro-mirror for operation. A detailed analysis on the electromechanical characteristics of a linear micro-mirror for raster-type scanning provided by ST Microelectronics is provided. The performance of the electrostatic comb drive actuation together with the mechanical characteristics of the micro-mirror design were evaluated using theoretical calculations and numerical simulations. Finite Element (FE) simulations for modal, mechanical and electrostatic analyses were performed using CoventorWare 10. Results were compared against measurements undertaken using an electromechanical probing station and a MOEMS optical test bench. The relevant methodologies considered for the analysis of the linear micro-mirror were applied to develop a novel design of a single layer two-directional comb-actuated MEMS scanning micro-mirror aimed for Lissajous scanning with a target optical resolution of 800x600 (SVGA). A verification step on a reported SOIMUMPS 1D micro-mirror was carried out to verify the operation of 2D micro-mirror scanners having one structural layer.