August 19, 2014
Octopus-Inspired Camouflage Sheet Developed By US, Chinese Research Team
redOrbit Staff & Wire Reports - Your Universe Online
Drawing inspiration from the color-changing capabilities of cephalopod skin, researchers have developed a new camouflage sheet capable of quickly reading its environment and adapting to mimic its surroundings.
The technology, known as an optoelectronic camouflage system, is based on the ability of the octopus, squid and cuttlefish to alter their appearance to hide from predators and as a way to issue warnings. In fact, in addition to changing color, the creatures can alter the shape and texture of their skin, said National Geographic’s Ed Yong.
“No man-made technology comes close” to matching the transforming talents of cephalopods, Yong said. However, the US and Chinese engineers behind this new technology – which is detailed in Monday’s edition of the Proceedings of the National Academy of Sciences (PNAS) – is “at least… nudging in the right direction,” he added.
Lead investigators Cunjiang Yu, assistant professor of mechanical engineering at the University of Houston, and John Rogers of the Beckman Institute for Advanced Science at the University of Illinois at Urbana-Champaign have developed a prototype that currently works in black and white, with shades of gray.
However, Yu said in a statement that the technology could be enhanced to operate in the full color spectrum. The device has a flexible skin comprised of extremely thin layers of semiconductor actuators, switching components and light sensors with inorganic reflectors and organic color-changing materials that combine to allow it to autonomously color-match its background.
“This is the first full, working system of its kind - it looks like a thin sheet of paper,” Rogers told BBC News science reporter Jonathan Webb. “But it's nothing close to being ready to deploy, in a military setting or anything else. It's really a beginning point, to focus on the engineering science around how you might create systems that have this type of function.”
“This is by no means a deployable camouflage system but it’s a pretty good starting point,” he told Yong. Rogers explained that he and his colleagues are working to develop adaptive sheets that can wrap around solid objects and change their appearance – technology that could allow military vehicles to automatically camouflage themselves, or clothing that can change its color based on current lighting conditions, the National Geographic reporter added.
Yu, Rogers and a team of experts in the fields of biology, materials, computing and electrical engineering joined forces to develop the optoelectronic camouflage system, Webb noted. The three-layer design of the device was copied from the skin of the marine animals, as they have a top layer that contains the colors, a middle layer that drives the color changes, and a lower layer that senses the background patterns to be copied, he reported.
In comparison, the camouflage system is a 16-by-16 grid of squares, each of which is comprised of multiple layers, Yong explained. The top one contains heat-sensitive dye that can change color from black at room temperature to colorless at 47 degrees Celsius and back again.
The next layer is a thin piece of silver used to create a bright white background, and the one below that heats the dye and controls the color. The final layer contains a light-detector in one corner, and each of the layers above it have notches removed from their corners to allow this instrument to always view the surrounding environment. The device also possesses a flexible base, allowing it to bend and contract without breaking.
“So, the light-detectors sense any incoming light, and tell the diodes in the illuminated panels to heat up,” Yong explained. “This turns the overlying dye from black to transparent. These pixels now reflects light from their silver layer, making them look white. You can see this happening in the videos below. Here, different patches of light are shining onto the material from below, and it’s responding very quickly.”
“While the most valuable applications would be for defense or industry, Yu said consumer applications such as toys and wearable electronics also could offer a market for such a technology,” the University of Houston said. “Another possibility? Luxury carmakers now try to give a car’s occupants the sensation that the car has disappeared by deploying cameras to shoot videos on the passenger side of the car and using LED mats to display the view. Yu said this technology could be incorporated for a similar purpose.”
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