Revolutionary Kirigami-Inspired Design Achieves Unprecedented 200% Stretch in Multi-Pixel Display Arrays

A research team at POSTECH (Pohang University of Science and Technology) has achieved a significant milestone by creating the world’s first technology that allows for consistent stretching across multiple pixels in stretchable displays. This achievement overcomes a major obstacle in the field and has been recognized as a Back Cover article in the prestigious journal Advanced Functional Materials. Led by Professor Su Seok Choi and Ph.D. candidate Jun Hyuk Shin from the Department of Electrical Engineering, the team’s work represents a significant step forward in the evolution of display technology.

The landscape of display technology is rapidly evolving, with a focus on shape-deformable devices. Foldable, bendable, and slidable displays have already made their mark, and the spotlight has now shifted to stretchable displays, particularly in South Korea. These displays have the potential to integrate with sensors, creating electronic skin-like systems that mimic the flexibility and softness of human skin. The development of fully stretchable technology with precise control is essential for the advancement of these next-generation devices.

The Challenges of Current Stretchable Display Technologies

Most existing stretchable technologies rely on an extrinsic approach, utilizing rigid electronic components connected by wavy or serpentine interconnects. While this approach allows for some mechanical deformation, it comes with limitations such as a reduced stretching range, lower pixel density, and a decline in display uniformity and image quality under strain.

On the other hand, the intrinsic approach, which utilizes inherently stretchable materials like silicone or rubber, is considered the ideal path forward. However, these systems have struggled with non-uniform strain distribution, especially in multi-pixel arrays. The variation in deformation across pixels leads to inconsistencies in color, brightness, and signal transmission.

The root of this issue lies in geometry and physics: when a stretchable material is stretched, areas farther from the point of tension experience less strain. This disparity is akin to how the center of a rubber band stretches more than its edges. Achieving uniform stretching across all pixels in an intrinsically stretchable system has proven to be a critical and unresolved challenge.

To tackle this obstacle, the POSTECH team turned to kirigami, a traditional Japanese paper-cutting art. By incorporating finely patterned incisions on the stretchable substrate, they were able to distribute mechanical stress evenly during stretching.

As a result, the team successfully achieved uniform stretching of up to 200% in all areas of a 7×7 pixel array. Additionally, they introduced a “strain stopper”—a rigid structure embedded in specific areas of the material—to prevent unwanted deformation in certain directions. This breakthrough marks the first instance of fully controlled, uniform, multi-directional stretching in a multi-pixel stretchable display system.

The researchers also integrated chiral liquid crystal elastomer (CLCE)—a material that is both intrinsically stretchable and mechanochromic, changing color in response to mechanical stress. By combining CLCEs with their kirigami-structured platform, they developed a stretchable display capable of revealing hidden patterns only when stretched. This feature holds significant potential in encryption and anti-counterfeiting applications.

Furthermore, the CLCEs exhibit circular polarization selectivity, enabling high-level optical security. When combined with a polarization filter, the display can showcase different colors or patterns based on the viewing angle, allowing for dynamic, angle-dependent, secure information display. This technology could pave the way for encrypted displays that are invisible to the naked eye but detectable using specialized optical equipment.

Applications in the Real World

This breakthrough not only addresses a longstanding mechanical challenge in stretchable displays but also introduces new possibilities in wearable electronics, flexible displays, and data security. By demonstrating a functional system that combines consistent mechanical performance with advanced optical capabilities, the team has laid the groundwork for future commercial stretchable devices.

Professor Choi remarked, “By solving the issue of non-uniform deformation, this work significantly enhances the practical potential of inherently stretchable materials such as silicone, rubber, and artificial skin. It will also make a substantial contribution to the advancement of stretchable optical components and secure display technologies.”