Vertical Microlens Scanner for 3D Imaging

Abstract

We have designed, fabricated, and demonstrated a static vertical microlens scanner with large static displacement and low (<10V) driving voltage, using silicon-on-insulator (SOI) technology. The unique isolated vertical combdrive sets and the coupled-torsion flexure design provides for both upward and downward piston motions and the low driving voltage. Single- directional devices demonstrate maximum static downward displacement of 8 µm at 10 Vdc actuation voltage. Bi-directional devices demonstrate vertical actuation from -6.5 µm to +9 µm also at sub-10 V. The devices have mechanical resonant frequencies near 400 Hz, and when operated at resonance, a vertical displacement of up to 55 µm peak-to-peak is achieved at up to 7 Vrms. The lens motion shows near pure piston motion with very small tilt angle of less than 0.034° and the compensation of the tilt using an isolated comb bank is demonstrated.