Auto Focus Three-Location Ball Support for Tilt Stability

The patent applies local quality by differentiating the sizes of balls in the supporting structure. Specifically, it uses a combination of large balls and small balls at different locations rather than uniform balls. The large balls are positioned at critical contact points to maintain stable support, while small balls fill other positions. This non-uniform distribution resolves the contradiction by creating localized quality differences that prevent contact point changes and tilt faults, thereby improving reliability without requiring complete structural redesign.

The patent employs asymmetry by arranging balls of different sizes in an asymmetric pattern rather than a symmetric uniform arrangement. The asymmetric distribution of large and small balls creates a stable contact configuration that prevents the AF carrier from tilting during movement. This asymmetric structure ensures that contact points remain consistent, solving the reliability issue while maintaining reasonable structural complexity.

The patent applies local quality by strategically positioning large balls at specific locations where they are most needed for horizontal stability, rather than uniformly increasing all ball sizes. The large balls are placed at outer support positions to maximize horizontal stability, while smaller balls are used in positions where they adequately provide support. This localized differentiation achieves consistent point contact by matching ball size to functional requirements at each location.

The patent uses partial action by employing only three large balls instead of four, positioned at critical locations for horizontal support. This partial application of the large-ball concept is sufficient to achieve the desired horizontal stability and consistent point contact, avoiding the excessive complexity and manufacturing precision requirements that would result from using four equally large balls throughout the structure.