Performance improvement of a two-axis radial-vertical-combdrive scanner by using a symmetric spring design

A symmetric cross-bar spring structure is employed to improve the performance of a two-axis gimbal-less micromirror driven by radial vertical combdrive actuators. The actuators are hidden underneath the mirror to minimize the device form factor. The device is fabricated by the SUMMiT-V surface micromachining process. The entire improved cross-bar spring structure is made of the same layer with a 1-mum thickness and the torsion springs are shortened to suppress the lateral instability. The mechanical rotation angles are plusmn5.33deg (50.7 V) and plusmn6.04deg (52.8 V) for rotation about the x- and y-axes, respectively.