Extending displacements of comb drive actuators by adding secondary comb electrodes

[[abstract]]A method for extending displacements of comb drive actuators has been demonstrated in this paper. Differing from other methods which modify the shape of suspension to shift the maximum of the lateral spring constant curve, or adjust the lengths of the individual comb fingers to reduce the equivalent electrostatic spring constant, this method changes the configuration of comb electrodes to shift the minimum of the equivalent spring constant curve. In addition to the original set of comb electrodes, a set of secondary comb electrodes was added into a comb drive actuator. By sequentially powering these two sets of electrodes, the comb drive can acquire more displacement than the original. The feasibility of this method was examined based on the existing theories and simulation software. An inequality that predicts the extending displacement after using this method was given. Based on this inequality, additional displacement could be achieved by adding one set of secondary comb electrodes and switching them sequentially. In our experiment, a case with 40.6% additional displacement has been observed. This value is consistent with the result derived by the model presented in this paper.[[fileno]]2020205010007[[department]]動機