‘Skin-like’ full-color display can be applied to plastics, fabrics
The approach was inspired by nature, where the skin of animals such as chameleons, octopuses, and squid are able to change skin color without requiring a light source. In contrast, manmade displays require a light source, filters and a glass plate, and are inflexible.
“All manmade displays – LCD, LED, CRT – are rigid, brittle and bulky." says Professor Debashis Chanda of UCF’s NanoScience Technology Center and the College of Optics and Photonics. "But you look at an octopus, they can create color on the skin itself covering a complex body contour, and it’s stretchable and flexible. That was the motivation: Can we take some inspiration from biology and create a skin-like display?"
The new method uses an ultrathin nanostructured surface that reflects ambient light and whose color is voltage controlled. It is created by sandwiching a thin liquid crystal layer over a metallic nanostructure "egg carton" that absorbs some light wavelengths and reflects others depending on the voltage applied to the liquid crystal layer.
The interaction between liquid crystal molecules and the nanostructured metallic surface is key to enabling a polarization-independent, full-color tunable display. Previous research has resulted in displays having a limited color palette.
To demonstrate the color-changing abilities of their nanostructured display, the UCF researchers used an image of an Afghan girl from National Geographic. (Credit: University of Central Florida and National Geographic)
The display itself is a few microns thick – thin enough to be able to be applied to flexible materials. While the implications are potentially large for existing displays used in TVs and mobile phones, the researchers see even more opportunities for entirely new categories of displays.
"Your camouflage, your clothing, your fashion items – all of that could change," says Chanda. "Why would I need 50 shirts in my closet if I could change the color and pattern?"
The nano-imprinting technique used to create the display is described as simple and inexpensive. According to Chanda, "This is a cheap way of making displays on a flexible substrate with full-color generation. That’s a unique combination."
For more, see the paper in the journal Nature Communications: "Polarization-independent actively tunable colour generation on imprinted plasmonic surfaces."
University of Central Florida: www.ucf.edu