The ability to manipulate and characterize materials on the nanoscale is important to the development of a number of nanotechnologies. Nanopositioning devices are able to move objects through small distances with nanoscale resolution, and are available commercially either as stand-alone devices or as integrated structures in other instrumentation such as atomic force microscopes. Comb drives are one type of actuator for nanopositioning systems and use electrostatic forces between the teeth of metallic combs for precise movement at small scales. Jason Clark, an assistant professor of electrical and computer engineering and mechanical engineering at Purdue University, has designed a novel nanopositioning device called a monolithic comb drive in which the stator and shuttle are mechanically connected. In conventional comb drives, these components are not connected. Clark states that the advantage of the new design lies in its ability to deflect in multiple directions as well as to reduce measurement error.
Clark recently presented results of his modeling on monolithic comb drives at the University/Government/Industry Micro/Nano Symposium in Louisville, KY. The modeling showed that deflections of 7.6 microns in the x-direction and 7.9 microns in the y-direction are possible with the use of 3 to 4 volts, and Clark states that larger deflections may be possible with the use of longer comb drive fingers. The modeling was performed using finite element analysis as well as 3D lumped analysis using Sugar 2, a MEMS simulation tool that Clark developed and plans to make available on the nanoHub website.
Many applications of nanopositioning are possible, including nanomanufacturing; biological and medical imaging, manipulation and analysis; industrial metrology; precise optical devices needed in astronomy; and data storage.
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Image from Clark, J.V. “Modeling a Monolithic Comb Drive for Large-Deflection Multi-DOF Microtransduction” University/Government/Industry Micro/Nano Symposium, 2008. Reprinted with permission from Dr. Jason Clark.
