THREE-DIMENSIONAL SIMULATIONS OF THE INKJET PRINTING PROCESS FOR PLED DISPLAY

摘要

Because the inkjet deposition process reduces manufacturing costs and process steps when compared with the traditional etching and/or lithography, it seems to be an attractive alternative in the PLED display manufacturing processes. However, some microflow issues in the deposition process should be carefully treated to ensure the manufacturing quality of the PLED display. The droplets dispensing from the inkjet head, which generally contains an array of nozzles, have a volume in several picoliters, while each nozzle responds very quickly and jets the droplets into cavities on substrates with micrometer size. The nature of droplet impingement depends on the material properties, the initial state of droplet, the impact parameters and the surface characteristics. The commonly chosen non-dimensional numbers to describe this process are the Weber number, the Reynolds number, the Ohnesorge number, and the Bond number. This paper discusses the influence of droplet initial velocity on microflow characteristics in the deposition process via a numerical approach. The numerical investigations show that for the studied droplet and cavity size, an acceptable velocity range has been found to ensure the deposition quality, while this result agrees well with existing industrial experiences. The numerical simulation seems to be an efficient and reliable way to evaluate the inkjet deposition process.