Two-dimensional selectively thinned steel micromirrors

Abstract

This thesis mainly deals with electromagnetically actuated resonant steel MOEMS scanners developed for a scanner-based projection system and focuses on the design of micromirrors to achieve QVGA and VGA specs. Types of scanners designed for this work are 2D gimballed torsional scanner and its design variations with the addition of sub-arms and increasing the number of beams in inner and/or outer frames. Stainless steel 420 is used as the structural material. Selective thinning is applied in the fabrication of some designs. Resonant-mode dynamic actuation is done with a time-varying current carrying external coil. Two di erent techniques are used for the fabrication of scanners: (i) electrochemical etching after photolithographic process (ii) electric discharge machining (EDM). In order to increase the total optical scan angle (TOSA), designs favoring the mechanical coupling are employed.