Multi-degree-of-freedom active alignment for camera modules via a sequential method and streamlined setup

The cumulative misalignments in optical modules have become a major constraint on imaging quality, making precision alignment crucial in advanced manufacturing. However, traditional passive alignment is inefficient, and existing active alignment (AA) often relies on specialized equipment such as wavefront sensors, struggling to balance accuracy, speed, and practicality. This study introduces a sequential AA method using the modulation transfer function (MTF) as the key metric. The proposed method implements a sequential process: first, compensating for lens group decenters using a sensitivity matrix derived from defocus curves; second, optimizing lens group tilt via Bayesian optimization (BO); and finally, fine-tuning the image sensor by leveraging physical information from multiple fields of view (FoVs). The experimental results demonstrate that our method achieves alignment in merely 8.485 seconds, which is 59% faster than the traditional search-based method, while attaining a superior average MTF compared to mainstream solutions. This approach provides an accurate, efficient, and practical pathway for multi-degree-of-freedom AA of camera modules, with substantial potential for industrial application.