Electrostatic combdrive-actuated micromirrors for laser-beam scanning and positioning

We describe the design and fabrication of surface-micromachined resonant microscanners that have large scan angles and fast scan speeds. These scanning micromirrors, which are hundreds of micrometers on a side, are driven by electrostatic-comb actuators and have resonant frequencies in the kilohertz range. Fabricated with two or three structural layers of polysilicon, the scanners are compact, extremely light in weight, and potentially very low in cost. Their power consumption is also minimal because the capacitive motors draw very low currents. High-precision positioning (0.01° dynamically and 0.038° statically) over a large angular range (up to 28° optical angle) makes the micromirrors suitable for a variety of optical applications such as laser scanners and printers, displays, holographic data storage, and fiber-optic switches. We have demonstrated microscanners of this type in bar-code readers, which are important devices with a growing number of applications in many industries