High‐precision and high‐stability inkjet printing technology for QD color converter‐type micro‐LED display

Abstract This paper reports on the development of a specialized inkjet printing head and equipment for high‐resolution printing of QD dispersed inks. First, to achieve a robust process, we proposed an inkjet head design compatible with higher ink viscosity and with an ink circulation system to avoid particle aggregation. Further, we introduce a multi‐restrictor inside the head to minimize ink fluid pumping pulsations on the print head and a drive‐per‐nozzle technology with individual nozzle waveform control. Results include down to 0.8 pL ± 1.8% droplet variation across all nozzles, with a three‐sigma accuracy 1.0 μm for droplet landing position. By combining optimized ink, inkjet head, and equipment technology, we successfully fabricated color converter‐type micro‐LED display panels.