Color‐Tunable SWIR Upconversion Display Based on InGaN Red MicroLEDs

ABSTRACT Smart interactive displays that integrate multiple functions for information visualization have become increasingly important in the intelligent era. Color‐tunable upconverter displays (UCDs) convert photons from the infrared to the visible light spectrum and allow visualization of multiple signals on a visible display in accordance with external changes. In the study, we propose a new color‐tunable short‐wavelength infrared (SWIR) UCD based on InGaN red micro‐light‐emitting diodes (microLEDs) and InGaAs/InP micro‐photodiode (microPD) integrated using flip‐chip bonding technology. The proposed UCD features a 960 × 540 array with a pixel of 10 µm and a pitch of 15 µm, reaching 1600 pixels per inch (PPI). Under 1550 nm laser illumination, the fabricated UCD exhibits a maximum current density on/off‐ratio of 76 at 5 V, photon‐to‐photon conversion efficiency of 1.3% at 7 V, turn‐on voltage of 3.2 V at dark and only 1 V at a low laser power density of 10 mW/cm 2 , maximum‐luminance on‐off ratio of 1.6 × 10 4 at 3 V, and maximum‐luminance linear dynamic range of 75 dB at 3 V. Besides, the UCD can show the mask images and videos through the 1550 nm laser illumination or even the incandescent bulb as the light source. More importantly, not only does the luminance of the UCD increase with the infrared power density, but also the color gradually changes from red to yellow. The superiority of color‐tunable SWIR UCD based on InGaN red microLEDs opens new possibilities for the development of intelligent displays and has promising multi‐disciplinary applications.