Novel "Auxetic Meta-Display" Widens as It Stretches to Keep Images in the Correct Aspect Ratio

Researchers at the Korea Institute of Machinery and Materials (KIMM) have developed a new meta-display system based on a stretchable LED matrix that, they say, can cleverly avoid distorting the displayed image.

Putting displays on flexible and even stretchable substrates isn't a new concept, but when you move beyond simply curving a display into stretching it you hit a snag: The further you stretch the display, the more distorted the image becomes — turning perfect squares into wide-aspect rectangles.

The "auxetic meta-display" created by first author Bongkyun Jang and colleagues, though, avoids the problem — by using a material with a Poisson's ratio of negative-one, meaning that for whatever amount it's stretched lengthwise it will also grow the same amount width-wise and thus preserve the aspect ratio of the displayed image.

The team's work comes from a 2019 project on meta-display technologies built around micro-LED systems, and uses the same core display type. The new prototype is built using micro-LED roll transfer technology and applied to a circuit board designed using kirigami concepts — the Japanese art of paper cutting, closely aligned to origami and often used in the production of electronics designed to flex or stretch.

No path to commercialization of the technology has yet been detailed, but the researchers say they are hoping the project will be of interest to fields including wearables displays, phototherapy, and skincare, as well as in the creation of "ultra-realistic metaverses."

The work has been published under open-access terms in the journal Advanced Functional Materials.