Large rotation actuated by in-plane rotary comb-drives with serpentine spring suspension

In-plane rotary comb-drives suspended by serpentine flexures were demonstrated to achieve larger rotation angles than those suspended by clamped straight beams. The serpentine flexures enabled the in-plane rotary comb-drives to mechanically rotate over 9° in each angular direction at driving voltage bias of less than 60 V. The resonant frequencies of such devices were measured to be about 410 Hz. The devices under test were made of single-crystal silicon and had dimensions of about 1 mm × 1 mm. These large stable rotation angles at lower driving voltages were designed based on the principle of radial instability.