Study of a high-efficiency, -precision, one-shot OCA dispensing technique

This study presents a technique for fast precise coating an optically clear adhesive (OCA) layer. A well-sealed loop dispensing system and a small multi-nozzle array are developed. Step-difference depth for obtaining highly reliable adhesive thickness is schemed to facilitate estimation of the total amount of adhesive needed for dispensing, and thus save on subsequent procedures such as shaving and OCA repair. The distribution method for OCA-droplet array is based on a 'middle-dense, outer-sparse, up-down-bilateral symmetry' strategy whereby air bubbles are expelled from gaps in the droplet array. Experimental results show that the developed one-shot adhesive dispensing technique is a highly efficient for the bonding task and encapsulation of LED (Light Emitting Diode) arrays with microelectronic chips.