Panasonic Production Engineering Co.,Ltd. - High resolution inkjet printing technology for QD color converter on Micro LED

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 0.8pL+/-1.8% droplet variation across all nozzles, with 3sigama accuracy of 1.0um for droplet landing position. By combining optimized ink, inkjet head and equipment technology, we successfully fabricated color converter-type Micro LEDs display panels.