Biaxially Stretchable Active‐Matrix Micro‐LED Display with Liquid Metal Interconnects

Abstract

A stretchable active‐matrix (AM) display is a next‐generation display that breaks away from displaying limited information on flat and curved screens. However, the implementation of stretchable displays requires much more complex fabrication processes and meticulous efforts compared to traditional flat/curved displays. Here, the biaxially stretchable AM micro‐light emitting diode (LED) display on polydimethylsiloxane (PDMS) with liquid metal (LM) interconnects is reported. The pixel islands consisting of oxide TFTs and micro‐LEDs, which are fabricated on the polyimide (PI) substrate, are formed through green laser cutting and transfer to the PDMS substrate. LM interconnects integrate on the pixel island and PDMS by a lift‐off process. The oxide TFTs and micro‐LEDs comprising the 2T1C (2 TFT + 1 capacitor) pixel circuit on the PI island, along with LM interconnects, demonstrate stable electrical characteristics even under a relaxed state as well as when biaxially stretched up to 24%. For 24% stretching of display pixels with the same ratio of PI island and LM interconnects, the LM interconnects operate at 48% stretching. The combination of pixel island array and LM interconnects successfully demonstrates the implementation of a two‐axis stretchable display capable of displaying characters of “A”, “D”, “R”, and “C” through AM driving.

Strain-Sensor-In-Pixel Technology for Resolution-Sustainable Stretchable Displays

“…However, stretchable displays must satisfy stricter requirements than those imposed on existing flexible or foldable displays to maintain their electrical and optical properties under mechanical stretching. , While commercial products with flexible or foldable displays have recently emerged, the absence of commercial products with stretchable displays indicates an even more challenging technological hurdle. This difficulty arises from variations in the net display area, not during folding conditions but during stretching conditions .…”