Infrared night-vision imaging systems typically installed in military vehicles and planes cost about $100,000, making them impractical for most civilian applications. Researchers at ORNL, however, have developed a revolutionary Uncooled Microcantilever Infrared Camera using microcantilevers, which are similar to miniature phonographic needles. The new technology could improve resolution and reduce the cost to less than $1,000 if mass production can be achieved.
In automobiles, night-vision cameras could allow drivers to see past oncoming headlight glare and beyond what they can see with headlights. These cameras would most likely be used much the way drivers use rear-view mirrors, for occasional but vital monitoring of traffic. Aboard airplanes, infrared cameras could aid pilots when weather conditions reduce visibility.
While conventional infrared night-vision systems require cryogenic coolers, sophisticated optics and costly sensor materials, ORNL's Uncooled Microcantilever Infrared Camera uses inexpensive, mass-produced silicon microcantilevers and a mirror.
"The heart of this novel camera consists of a mirror and a cantilever placed at the focus of the mirror," said Thomas Thundat, principal researcher and a member of ORNL's Molecular Imaging Group, a part of the Health Sciences Research Division. "The mirror forms an infrared image of the object to be photographed.
"Brighter areas of the image formed at the focal plane have a higher number of photons and are, therefore, hotter compared to darker areas. The infrared photograph is taken by scanning the cantilever sensor over the image at the focal plane."
As the cantilever scans the focal plane, the amount of cantilever bending changes with brightness of the image because of heat absorption by the cantilever. This bending is monitored as electrical resistance changes in the cantilever and is displayed as a two-dimensional photograph of the object.
Instead of scanning using a single cantilever, ORNL's team is developing a device that can generate instantaneous photographs by using a two-dimensional array of microcantilevers closely packed on a support structure.
Thundat and colleagues Bruce Warmack, Rick Oden and Panos Datskos envision their camera being used in hundreds of industry process control systems, by the military, in automobiles, airplanes and in security systems. It could also be adapted for use by firefighters and in energy conservation.
"The main advantages of our Uncooled Microcantilever Infrared Camera are its lower cost, reduced size and the fact it doesn't require liquid nitrogen cooling," Warmack said.
Research for the uncooled microcantilever infrared camera was funded in part by DOE's Environmental and Biological Sensor Development Program and by the National Science Foundation.
ORNL, one of DOE's multiprogram research facilities, is managed by Lockheed Martin Energy Research Corporation.