Invisible Butterfly Wings Could Inspire Future Tablets/E-Readers

For a long time now, on-the-go readers and workers have had one common enemy: sunlight. Trying to read a good book or even just your emails in the glare of the Sun has been a massive source of frustration for tablet and e-reader owners. Now however, experts are looking to a unique species of butterfly to make reflective screens a thing of the past.

The glasswing butterfly (Greta Oto) is a stunning example of camouflage at its best. Instead of trying to match its wings with the colors that surround it, the aptly named insect simply boasts "invisible wings" that are so transparent that they could serve as paper-thin windows.

But unlike your basic window, these wings hardly reflect any light. Close up, the wings of G. Oto look like spindly twigs branching out from a barely-noticeable jet-black thorax. Only small strips of white would reveal this butterfly's presence from afar, even with the Sun shining directly on it.

Researchers at the Karlsruhe Institute of Technology (KIT) determined that amazingly, depending on the view angle, the specular reflection of light off a glasswing's surface varies between two and five percent. That's significantly lower than anything ever achieved with glass planes - even specially treated ones - which have only ever been able to achieve a minimum of eight percent reflection at very specific angles.

And most interesting of all, the butterfly wings also reflect or suppress infrared and ultraviolet light - visible to some small animals and potential avian predators.

So how does the glasswing pull this off? According to new electron microscope analyses, complete and utter chaos is key. Results were published in the journal Nature Communications.

Under the direction of researcher Hendrik Hölscher, the KIT team found that irregular nanostructures on the surface of the butterfly wing are what cause this significant reduction in reflection. Called "nanopillars," these structures varied wildly in high (between 400 and 600 nanometers) and were even spaced irregularly, ranging between 100 and 140 nanometers - about one thousandth of the width of your average human hair. (Scroll to read on...)

"In contrast to other natural phenomena, where regularity is of top priority, the glasswing butterfly uses an apparent chaos to reach effects that are also fascinating for us humans," researcher Radwanul Hasan Siddique, who discovered this effect, explained in a statement.

Now, Hasan Siddique, Hölscher, and their colleagues are investigating how exactly these wings develop with such stunningly chaotic surfaces - a boon that they hope could be applied to the development of glare-free electronic screens in the future.

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