Surface-micromachined electrostatic-comb driven scanning micromirrors for barcode scanners

This paper describes the design and fabrication of micromachined resonant scanners that have large scan angles at fast scan speeds. Driven by an electrostatic comb motor, these 200 μm by 250 μm scanning-micromirrors can scan about 12° (optical) at the resonance frequency of 3 kHz with a sinusoidal voltage input of 20 V in amplitude. Fabricated with a four-poly-layer silicon-surface-micromachining process, these resonant scanners are compact, extremely light in weight, and potentially very low in cost. The power consumption is also minimal since the capacitive motor draws very little current. We have demonstrated the scanner as a laser-beam deflector in a barcode reader, a potentially important application that has a growing popularity in many industries