High‐precision and high‐stability inkjet printing technology for QD color converter‐type micro‐LED display
Hidehiro Yoshida, Shuhei Nakatani, Yukiya Usui, Daisuke Wakabayashi, Futoshi Ohtsuka
Abstract
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.