Modeling study of the dynamics of silicone-phosphor in jet dispensing process for LED packaging

Jet dispensing is one of the key technologies in LED packaging as the consistency of the dispensed volume can directly affect the LED color and quality. Studying the dynamics of silicone-phosphor during the jet dispensing process is of great value. In this paper, a multi-physical model was developed and verified by the experiments. The silicone-phosphor thread profile during the jet dispensing process and break-up time were obtained and analyzed. The effects of piston velocity, nozzle size and dispensing height on the jet dispensing process were studied. It is found that the proper piston velocity is about 2.0 m/s, and the optimized dispensing height is about 10 times of the diameter of the nozzle tip. Nozzle size can speed up the break time but the effect is limited. These findings will be helpful for dispenser design and dispensing technology development in modern LED packaging.