Integrated Folding, Alignment, and Latching for Reconfigurable Origami Microelectromechanical Systems

The design, implementation, and characterization of passively aligned reconfigurable three-dimensional (3-D) microelectromechanical systems via origami folding is presented. The process integrates into a two-mask pattern all of the features necessary for actuation, aligning, and latching segments into their correct positions under the influence of a single driving force with high tolerance to magnitude inaccuracy. Lorentz force folds the two-dimensional (2-D) elements out-of-plane. Their alignment is controlled by cascaded alignment features that create an initial interaction at coarse levels of alignment and deterministically drive the system to its as-designed final position. Reversible mechanical latches engage passively, preventing unfolding when the actuation force is released. The latches are designed to be able to be unlatched for future reconfiguration, either by returning to the unlatched state or by relatching into a second state. The proposed approach was demonstrated in an SU-8 corner cube connected by thin-film gold flexural hinges. The alignment mechanism is shown to correct for up to 11° of misalignment. The latches fasten and unfasten under forces of 13.1 and 12.5 μN, respectively. The average angle between folded segments of the final system is measured at 90.4° as compared with the design value of 90°, with a standard deviation of 0.6°.