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SEM micrographs of the resulting fiber
cross-section, illustrating the uniform
conservation of the cross-section
structure from the macroscopic
preform to the microscopic fiber.
(Credit: Fink Lab/MIT) |
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The team of researchers was led by Associate Professor Yoel Fink of the Department of Materials Science and Engineering (DMSE). Currently, the researchers are focusing their efforts on bringing the developed fiber web to the application level. The project currently stands at being able to capture 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 Fink. “This work constitutes a new approach to vision and imaging.” Optical fiber webs can provide a distributed imaging capability where the input comes from all sides of the material, and ‘blindness’ can be completely avoided.
The device does not depend solely on one main fiber and can still function even if part of the fiber is damaged. “We are saying, instead of a tiny, sensitive object [for capturing images], let’s construct a large, distributed system,” said Fink.
Less than a millimeter thick, the fiber web is composed of layers of light-detecting materials nested one within another. These layers consist of two rings of a light sensitive, semiconductor material that has a diameter of 100 billionth of a meter. Each of these rings is connected using four metal electrodes extending the length of the fiber. The metal electrode connected to the semiconductor ring is in turn enclosed in rings of polymer insulator that act as a divide between its neighbors.
These minute components are fabricated using a macroscopic cylinder, also known as preform. The preform is positioned in a specially designed furnace that melts the components and slowly draws them into miniscule fibers that maintain the initial arrangement of the range of layers. This method allows fabricating several meters of fiber.
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The camera is made of a collection of
polymer fibers, each of which consists
of eight semiconductor light sensors that
circle the center of the fiber, as shown
here in this scanning electron microscope
image. (Credit: Fink Lab/MIT) |
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A demonstration was performed by positioning a smiley face object between a light source and the fiber web which was linked up to an external amplifying electrical circuit and computer. The device works with the fibers measuring the intensity of light illuminating on them. This intensity is then translated to an electric signal. The fibers were also designed to identify color by distinguishing between different wavelengths of light.
Currently the images can only be retrieved through two separate wavelengths. The image produced a distinct pattern on the fabric mesh which was transferred to the computer for processing. The team developed an algorithm that compiles and translates the data into black and white images.
“This paper furthers our vision of designing fiber materials and fabrics with ever-increasing sophistication and complexity,” Fink added. He and his colleagues note that additional optoelectronic layers in the fibers will lead to crisper images that could be displayed in color.
TFOT has previously written about the camera with 6 million frames per second capability, which was designed to capture high-speed events such as shockwaves, communication between living cells, neural activity, laser surgery, and elements of blood analysis. You can also check out our article on Scallop Imaging surveillance camera, which sports seven-megapixels without fisheye distortion, and provides a 180-degree full situational awareness image through use of five video feeds. You are also welcome to read our coverage of the invisibility cloak, which could eliminate the impression of an object placed underneath it.
Additional information on MIT’s fiber web can be obtained at MIT’s website. |
