Design and fabrication of 2D fast electrothermal micromirrors with large scan range and small center shift

We report an elliptical micromirror actuated by a curved electrothermal multimorph that bends and twists upon controlled Joule heating. The mirror plate is elliptical with 92 μm major axis and 142 μm minor axis. The micromirror has an optical scan angle of 22° at 0.37 V applied voltage or 9 mW power input. Mirror-center shift produced by multimorph bending and twisting compensate each other and is only 14.5 μm at an optical scan angle of 22°. The curved actuator shape maximizes chip-area utilization and ensures a high resonant frequency. The first three resonant modes are at 3.9 kHz, 8.6 kHz and 17 kHz. Two-dimensional (2D) optical scanning is demonstrated using the second and third resonant modes.