Large rotation angle micromirror based on hypocycloidal electrothermal actuators

A large rotation angle micromirror using hypocycloidal electrothermal actuators (HEAs) is presented. The mechanical rotation angle of the micromirror is ~35° at 2.6 V in nonresonant mode. The Cr/Au coated square mirror plate is supported by two groups of HEAs in order to achieve single axis rotation. Four Al/Si bimorph structures are staggerly connected in parallel to form a HEA. This structure is experimentally demonstrated to increase the deflection angle. Moreover, the rotation axis keeps still and there is no lateral shifting effect. The -3 dB cutoff frequency was found to be about 29 Hz as the large signal frequency response.