The challenges and focuses on plastic welding by picosecond laser in the field of camera module assembly

Polycarbonate (PC) and cyclic olefin copolymers (COC) are extensively employed in optical lenses due to their exceptional optical properties. However, mechanical clamping forces connecting lenses to each other and barrel within the camera module assembly (CMA) can lead to image quality degradation. Laser welding of plastics has emerged as an innovative technique for addressing this issue. Picosecond laser welding has successfully achieved joints between PC to PC, PC to COC, and COC to COC under optical contact (OC) and non-optical contact (NOC) conditions. Comprehensive analyses of weld zone morphology and mechanical properties have revealed diffusion bonding as the mechanism for joint formation and brittle fracture as the mechanism for fracture. By contrasting the requirements of camera module assembly with these plastic joints, the joint bonding strength is deemed adequate. However, numerous challenges and limitations hinder the advancement of laser plastic welding within the CMA field. Pertinent suggestions have been provided to address these obstacles, including the optimization of welding parameters, utilization of a high-NA focal system, and surface polishing of materials. The implementation of improved laser welding techniques is expected to significantly contribute to the future development of CMA.