Design and fabrication of an electrothermal microactuator for multi-level conveying

During the past years, a variety of microactuators developed for micro-conveyors have been presented. However, such micro-conveyors can only provide conveying motion in a single plane. Here an electrothermally driven microactuator with a capability of adjustable height is proposed, which may act as a basic unit for multi-level conveyors. This microactuator is based on the principle of thermal bimorph actuation with two long conveying fingers to exert out-of-plane bending motions in the transversal direction, which are connected and lifted by an initially curved height adjuster in the longitudinal direction. The devices can provide conveyance of micro-objects between two plane levels of different heights. The testing results show that the two fingers and a height adjuster can be actuated simultaneously and individually with little thermal crosstalk. The proposed device with a dimension of 900x100x4.5 mu m(3) can provide 5 mu m vertical displacements by the height adjuster at 1 V and 18 mu m lateral displacements by the conveying finger at 2 V. Simulations by finite-element program ANSYS 5.7 have been performed and widely match with testing results.