Take a look at this colourful character: it’s a robot chameleon (see video above).
Guoping Wang of Wuhan University, China, and his colleagues created it to show off their camouflage technology, which could one day allow military vehicles or body armour to blend perfectly into the background.
The chameleon is amodel covered in plasmonic displays, which produce colours by exploiting the interactions between nanoscale structures and electric fields. The team made the displays by taking a glass sheet bearing a grid of holes, each 50 nanometres across, and depositing gold on to it. This formed gold domes inside each hole. They then placed the sheet inside a casing filled with an electrolyte gel containing silver ions.
When light hits the gold nanostructures it produces, called plasmons, that determine its reflective and absorbing properties – in this case, making the glass sheet appear red. Applying an electric field deposits some silver ions on to the gold domes, modifying their properties and producing different colours. Reversing the field strips off these ions and restores the red colour.
The team experimented with different strengths of field and durations to find out which colours they could make. To emulate a chameleon’s, they used light sensors to recognise the background colour and apply the appropriate field.
At the moment the sensors are limited to recognising only the primary colours red, green and blue. A more advanced system should be able to detect any colours, says Wang. “This would fully merge the mechanical chameleon into the surroundings.” If these advanced sensors can be miniaturised, the same principle could be used to develop adaptive camouflage systems for use by the military, he says.
More on these topics:
This entry passed through the Full-Text RSS service – if this is your content and you’re reading it on someone else’s site, please read the FAQ at fivefilters.org/content-only/faq.php#publishers.