Fabricating Quantum Dot Color Conversion Layers for Micro-LED-Based Augmented Reality Displays

Colloidal quantum dots have attracted much attention for their potential application in the color conversion scheme of next-generation microdisplays. One of the possible methods to pattern these nanoparticles into arrays is to use quantum dot photoresists. We will demonstrate a high-resolution color conversion layer with a 1.5 μm by 4 μm subpixel size and a pixel density exceeding 2000 pixels-per-inch (PPI). The photonic characteristics are analyzed, and the estimated color conversion efficiencies are 9.51% for green and 16.55% for red. A full National Television Standards Committee (NTSC) (gamut coverage: 100%, area ratio: 114%) color gamut is achieved in a 992-PPI microdisplay by adding an optical reflector on the top. Without this reflector, the coverage drops to 82.9%. A comparative study found a steady improvement for the photoresist method over the past decade, and a color conversion layer with an even higher resolution can be expected.