New fabric 'can see farther than most shirts'

Posted by Emma Woollacott

Cambridge, MA - MIT researchers have developed a special fabric that acts as a camera, and have used it to take a rudimentary picture of a smiley face.

"This is the first time that anybody has demonstrated that a single plane of fibers, or 'fabric,' can collect images just like a camera but without a lens," said Associate Professor Yoel Fink of MIT's Department of Materials Science and Engineering (DMSE). "This work constitutes a new approach to vision and imaging."

Lenses, whether natural or man-made, have a limited field of view and are susceptible to damage. Optical fiber webs, in contrast, provide a distributed imaging capability right across the fabric's surface - if one area is damaged, other fibers can still function.

"While the current version of these fabrics can only image nearby objects, it can still can see much farther than most shirts can," said Fink.

The new fibers, less than a millimeter in diameter, are composed of layers of light-detecting materials nested one within another. The layers include two rings of a light-sensitive semiconductor material, with four metal electrodes contacting each of the rings. Each ring is encased in a polymer insulator.

The team starts with preform, of these elements which is placed into a special furnace that melts the components, drawing them into miniscule fibers that retain the original orientation of the layers. The process can produce many meters of fiber.

Fink's team placed a smiley face between a light source and a small swatch of the fabric, which was connected to an external amplifying electrical circuit and computer.

The fibers measure the intensity of the light illuminating them and convert it to an electrical signal. Importantly, they can differentiate between light at different wavelengths or colors.

The face was illuminated at two separate wavelengths, generating a distinct pattern on the fabric mesh that was then fed into a computer. From there, an algorithm created a black-and-white image of the object on a computer screen.

The researchers suggest the material could be used for soldiers' uniforms, for example, allowing them to look in all directions. It could be linked to a computer with a small display screen attached to a visor, providing the soldier greater awareness of his surroundings.

The research is published in Nanoletters.