Friday, March 28, 2008

Foldable, Stretchable Circuits

Continued from page 1

By Kate Greene

The research offers "a completely new circuit concept," says Zhenqiang Ma, an electrical-engineering and computer-science professor at the University of Wisconsin-Madison. Ma has previously built ultrafast silicon transistors on bendable substrates, which operate at high frequencies, making them useful for antennas built onto the wings of airplanes, for instance. (See "Record-Breaking Speed for Flexible Silicon.") While Rogers's transistors are slower, his integrated circuits have the advantage of being designed with the wavy geometry of thin silicon in mind, so that they can be optimized on a stretchy substrate.

Rogers says that one field in which the foldable, stretchable circuits could be useful is neuroscience. (See "TR10: Personalized Medical Monitors.") He is working on a project that could enable a thin sheet of electronics to wrap around the brain, monitoring electrical activity for indicators of future seizures in people with epilepsy. In addition, Rogers and his colleagues are building latex surgical gloves with integrated electronics that could add sensing functionally or, in some cases, provide tactile feedback for training surgical students.

"There are many applications for these new types of circuits," says Ma. "In some of the applications ... stretchable and foldable integrated circuits may be the only choice." He adds that the new integrated-circuit concept "has filled an important application gap" that rigid, chip-based circuits can't fill.