A novel electrostatically driven micromirror with lateral comb actuators and T-shaped torsion bars

There are many applications for micromirrors, such as laser communication, projection displays, optical scanners, optical switches, and so on. A novel electrostatically driven micromirror with lateral comb actuators and T-shaped torsion bars is proposed for the first time. It can be shown that the actuating force arm is larger and the actuating torsion moment is larger by using T-shaped torsion bars. It is also easily shown that the actuating voltage is lower than ever. At the same time, T-shaped bars can create higher in- and out-of-plane bending stiffness. Therefore, the micromirror is mechanically more stable and is prevented from pull-in to a great extent. The micromirror is fabricated by a standard bulk silicon process with novel isolation technology. The first test results show that the micromirror can rotate around the torsion bar and its side instability should be considered deeply for the flexibility of the bar connecting the comb actuators with the micromirror.