Scanning micromirror for large, quasi-static 2D-deflections based on electrostatic driven rotation of a hemisphere

•The theoretical model includes now the phase and is therefore more consistent.•The measured oscillation (at 1980 Hz) is analysed further and its deviations are discussed. Mainly the deviation from the theoretical model results from high-frequency oscillations of the stage itself. Furthermore, the oscillation at 1980 Hz is compared with another one at 1750 Hz where the movement is chaotic as predicted by the model.•The mechanical wear is analysed and an outlook regarding aspects of its future application is given.

A micromirror (mirror area 3.1 mm2) for laser tracking applications is presented. The mirror, which is based on a hemisphere, is designed to achieve large quasi-static deflection around two rotational axes by adapting the principle of ultrasonic motors. Here, the deflection of the mirror is achieved by a periodic momentum transfer from a stage with electrostatically driven oscillations. Due to the periodic hemisphere-stage-contact, the system has multiple degrees of freedom and is non-linear. A simple model of stage-hemisphere-interaction is presented and verified in order to identify design rules and adequate excitation regimes.The actuator is fabricated in standard SOI-technology. The final system is excited as well in a non-resonant (2000 Hz) as in a resonant mode (2900 Hz). Thus excitation frequencies over a wide range are possible. For a resonant operation of the stage, a maximum quasi-static deflection of the mirror of up to +/−35.2° with a maximum angular velocity of 732°/s is demonstrated. In this case, the crosstalk (movement perpendicular to desired direction) is less than 22%. For the non-resonant operation the crosstalk is reduced significantly (less than 10%). In this case, a quasi-static deflection of +/−10.5° is found.