Auxetic Meta‐Display: Stretchable Display without Image Distortion

Abstract

Mechanical metamaterials possess unusual mechanical properties that cannot be found in nature. Auxetic metamaterials have negative Poisson's ratios and tend to expand in a direction perpendicular to the axial extension direction. When the Poisson's ratio of a display circuit board is forced to be −1 by adopting an auxetic metamaterial, a display can be stretchable without image distortion, and this display is called a meta‐display in this study. The critical obstacles to implementing a stretchable display are large stretchability, high deformation uniformity, and low image distortion. The meta‐display overcomes these obstacles by incorporating micro‐LEDs and a kirigami‐based auxetic circuit board. An auxetic meta‐display with a stretchability of 24.5%, Poisson's ratio of −1, and no image distortion under uniaxial stretching is demonstrated. Finally, the roll transfer process enabled the scaling‐up of a 3‐inch meta‐display attachable to surfaces with non‐zero Gaussian curvatures. This conformity to the non‐zero Gaussian curvature helps realize biomedical applications such as wearable display, phototherapy, and skincare.

Materials and design strategies for stretchable electroluminescent devices

“…3j). 83 Micro-LEDs were transferred to a meta-printed circuit board (PCB) with a Poisson's ratio of À1 using the roll transfer technique. During stretching, the meta-PCB with the kirigami cutting lines formed a geometry of rotational squares and hinge structures (Fig.…”

Flexible micro-LED display and its application in Gbps multi-channel visible light communication

“…Recently, micro-light-emitting diodes (micro-LEDs) have emerged as next-generation display technology because of their superior ability to withstand moisture and provide ultrahigh luminance, and long lifespan compared to organic light-emitting diode (OLED) displays and liquid crystal displays (LCDs) [1][2][3][4][5][6] . Owing to these properties, researchers have applied micro-LEDs in smart wearable displays, automobile displays, stretchable displays, and outdoor signage 4,[7][8][9] . In addition, micro-LEDs can be used as transmitters in VLC due to their high switching rate, high energy efficiency, and high modulation bandwidth 10,11 .…”

High-Quality Microprintable and Stretchable Conductors for High-Performance 5G Wireless Communication

“…5G wireless technology is unleashing a huge Internet of Things ecosystem where wireless networks can serve billions of connected electronic devices. With the advent of 5G wireless technology, printed circuit boards (PCBs) need to be designed to address all the specifications when receiving signal transmissions, maintaining the signal integrity, and providing electrical connections. − Material considerations are the top aspect that must be evaluated for designing the PCBs. Higher frequencies and higher speed for 5G wireless communication require the appropriate conductors within the PCBs to capture and transmit various signals simultaneously. , Moreover, an additional problem is that the electronic devices become lighter and smaller.…”