A fast focusing method for CCM auto-focusing handlers

This paper proposes an auto-focusing method for production of compact camera module (CCM). The CCM AF (auto-focusing) handlers are mainly used in the final CCM production stage to measure and adjust the lens focus of CCMs. To improve the productivity of CCM AF handlers, we propose an efficient focusing method adjusting the lens focus quickly. The max-min-difference (MMD) method is newly developed to compute the focus value (efficiently, and two-stage searching method is also developed to find the best focus position quickly. Experimental results are presented to verify the usefulness of proposed method.