Summary: MIT Confidential 1
Title: Two-axis Optical MEMS Scanner
Inventors: Shorya Awtar, Klint Rose, Hoe Phong Tham
Two axis optical MEMS mirrors find use in many applications including raster scanning, image
projection, optical networking, bio-medical imaging, etc. In all these applications micro-mirrors
are employed to steer a beam of light. While successive single axis mirrors may be used to steer
the beam along multiple axes, a single two-axis mirror provides a simpler, more compact and
inexpensive alternative. In this document, we present a two-axis optical scanning mirror design
based on a novel resonant structure that provides optimal raster scanning action. The two
scanning axes are orthogonal and are designed to be highly decoupled. Furthermore, translational
errors of the mirror are eliminated by using the principle of virtual pivot for cantilever beams.
PZT electrodes are employed to excite the structure at the frequencies that correspond to its two
desired natural vibration modes. A simple fabrication process flow allows for mass production of
the device. Detailed analysis is provided to support the performance claims of the device.
Background and Prior Art
Optical mirrors have become critically important in areas of medical imaging, microvision,
displays, bar code recognition etc., where beam alignment, steering and scanning is needed.
MEMS technology enables miniaturization and integration of such optical mirror systems and
hence offers some very promising solutions to the above applications.