It looks a lot like a bicycle chain, except each link could comfortably rest on top of a human hair. Sandia National Laboratories in Albuquerque, N.M., has fabricated a microchain with a 50-μm distance between link centers (see the figure). Its designers expect it to be used in a number of microelectromechanical systems (MEMS) applications, like microcameras, mechanical timing, and decoding.
Even at this scale, a single, 50-link microchain could be used to rotate many drive shafts. It would then be unnecessary to place multiple MEMS motors in close proximity, as a separate driver usually powers each MEMS device. In turn, this would free up a lot of real estate on chips employing MEMS technology. Space is further saved because the microchain makes it possible to drive a MEMS device from a motor situated at a distance.
The microchain was designed to transmit power much like a typical drive belt. But silicon belts are spring-like and produce too much torque on gears not aligned in a straight line. Each link on the microchain, however, manages ±52° of rotation with respect to the preceding link without creating pressure on the support structure. This wide angle lets MEMS designers position a number of devices without many constraints. For details, go to www.sandia.gov.
