Influence of initial curvature effect on micromachined thermal bimorph actuation

While the micro bimorph structures are fabricated with enough initial curvatures or so-called geometrical imperfections, structural instability may occur to result in snap-through behaviors and exhibit large deflection strokes. The bimorph structures with various initial deflections ratios and various heating area ratios are simulated and fabricated to predict the stable and unstable regions of the curved bimorph structures with clamped boundary condition. Four major types of load-deflection curves are described and discussed. Testing results and some observations are reported.