After The two substrates are bonded, possibly an ultraviolet (UV) beam is directed, or heat or even a strain is partly used the sealant between the main and next substrates 510 and 520, for placing the sealant to fix the 1st and second substrates 510 and 520 (stage 5S in https://jiutustore.com/collections/optical-bonding-machine/Optical-Bonding-Machine