Range Extension of a Bimorph Varifocal Micromirror Through Actuation by a Peltier Element
IEEE Journal of Selected Topics in Quantum Electronics
Deepak (2015) Range extension of a bimorph varifocal micromirror through actuation by a Peltier element. IEEE Journal of Selected Topics in Quantum Electronics, 21 (4). Abstract-A bimorph varifocal micromirror actuated thermoelectrically by a Peltier element is reported. The single crystal silicon micromirror is 1.2 mm in diameter with a centered 1 mm diameter gold coating for broadband reflection. The actuation principle is capable of varying the micromirror temperature above and below the
... ent temperature, which contributed to a 57% improvement in the addressable curvature range in comparison to previously reported electrothermal and optothermal actuation techniques for the device. Altering the device temperature from 10 C to 100 C provided a mirror surface radius of curvature variation from 19.2 mm to 30.9 mm respectively. The experimental characterization of the micromirror was used as a basis for accurate finite element modeling of the device and its actuation. Negligible optical aberrations are observed over the operating range, enabling effectively aberration-free imaging. Demonstration in an optical imaging system illustrated sharp imaging of objects over a focal plane variation of 212 mm. Index Terms-Varifocal micromirror (VFM), Silicon-oninsulator multi-user MEMS processes (SOIMUMPs), Imaging, Thermal actuation, Finite element analysis, Optical MEMS.