Linearization of electrostatically actuated surface micromachined 2-D optical scanner

This paper presents an effective method of linearizing the electrostatic tr ansfer characteristics of micromachined two-dimensional (2-D) scanners, The orthogonal scan angles of surface micromachined polysilicon scanner are co ntrolled by using quadrant electrodes for electrostatic actuation, By using a pair of differential voltages over a bias voltage, we could improve the distortion of projected images from 72% to only 13%, A theoretical model ha s been developed to predict the angle-voltage transfer characteristics of t he 2-D scanner. The simulation results agree very well with experimental da ta. Differential voltage operation has been found to suppress the crosstalk of two orthogonal scan axes by both experimentally and theoretically. We h ave found that a circular mirror is expected to have the lowest angular dis tortion compared with square mirrors. Perfect grid scanning pattern of smal l distortion (0.33%) has been successfully obtained by predistorting the dr iving voltages after calibration.