Comparison of modeled and experimental behavior of a thermoelectrically actuated varifocal micromirror

The finite element analysis (FEA) simulation results of a bimorph silicon-gold varifocal micromirror (VFM) are reported. For a 1.2 mm diameter silicon VFM, the simulation shows that a variation of the surface radius of curvature (ROC) from 18.8 mm to 31.3 mm can be achieved between device temperatures of 10 °C and 100 °C. The ROC versus temperature relationship is highly sensitive to the values of Young's modulus and residual stress of the gold layer used in this model. The simulation results are compared with our experimentally measured ROCs obtained at different temperatures, yielding accurate modeling of the VFM behavior.