A droplet-intermixing printing method for high-uniformity pixel ink volume control based on integer programming

Abstract

Inkjet printing is a promising technology for new display mass production. However, a major challenge in inkjet printing applications is pixel ink volume nonuniformity caused by the volume error of droplets ejected from multiple nozzles. This nonuniformity can lead to nonuniform pixel film thickness and Mura defects in a display panel. To address this issue, an integer programming-based droplet-intermixing printing method for high-uniformity pixel ink volume control is proposed in this study. The printing method is used to homogenize the volume of ink deposited in each pixel by intermixing droplets from different nozzles to improve the whole-panel uniformity. To ensure that the droplet intermixing results meet the printing process requirements, a specific scheduling and printing planning model for the method is established. According to the droplet volume from each nozzle and the printing pattern, the most efficient printing path and nozzle ejection action are obtained by the established model while meeting the volume uniformity requirement of pixel ink. Experiments show that the proposed printing method can realize pixel film thickness error control under ±6 nm on a 400 cm2 display substrate, and the uniformity of different pixels is less than ±4.62 %. Compared with traditional method, the achieved uniformity is improved at 45.4 % under the same conditions. This method has been applied in printed display manufacturing equipment and achieved good results.