Lens Driving Device Coil Positioning via Segmented Restricting Protrusions
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Solution Overview
Problem
Existing lens driving devices face issues with coil positional shift due to external impacts, leading to conductor wire breakage and solder joint damage, and require excessive adhesive for stabilization, which affects productivity and accuracy.
Innovation Solution
A lens driving device design featuring a movable part with alternating first and second restricting protrusions, where the coil is wound with varying widths in opposing and non-opposing parts, preventing coil movement without strong adhesion, and ensuring secure fixation using minimal adhesive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of adhesive is used to bond the coil to the lens holding part, then the coil position is stabilized, but the productivity is reduced due to adhesive contamination
Solution Approach 1:
The lens holding part is segmented with multiple restricting protrusions (first and second types) distributed around its circumference. These protrusions divide the coil-winding area into multiple restricted zones, providing localized mechanical constraints that collectively stabilize the coil position without requiring excessive adhesive
Solution Approach 2:
The restricting protrusions create localized restricted spaces between them and the lens holding part's inner wall. Each restricted space provides targeted mechanical constraint for the coil conductor, ensuring stable positioning only where needed rather than requiring uniform adhesive coverage across the entire coil
2Productivity
If no adhesive is used to bond the coil, then the productivity is maintained, but the coil position shifts during external impacts
Solution Approach 1:
The restricting protrusions are pre-formed on the lens holding part before coil winding. These protrusions create predetermined restricted spaces that automatically constrain the coil conductor during the winding process itself, eliminating the need for post-winding adhesive application while ensuring position stability against external impacts
3Reliability
If the coil is tightly wound to prevent movement, then the position stability is improved, but the conductor wire tension increases and may cause breakage
Solution Approach 1:
Multiple restricting protrusions are distributed around the lens holding part's circumference, creating multiple separate restricted spaces. This segmentation allows the coil conductor to be constrained at multiple discrete locations rather than being subjected to uniform high tension across the entire winding, reducing the risk of wire breakage while maintaining overall position stability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively prevents coil movement and conductor wire breakage during external impacts, reducing the need for excessive adhesive and maintaining productivity while ensuring precise focusing in camera modules.
Implementation Method 1
A drive current is applied from the connection terminals via the lower plate spring to the coil to cause the lens holding part to move in the optical axis direction of the lens body
Data Source
AI summary
A lens driving device includes a movable part, a plate spring that movably supports the movable part, a coil provided on the movable part, and magnets facing the coil. An outer portion of the movable part includes protrusion opposing parts where first restricting protrusion and second restricting protrusions face each other in an optical axis direction and non-opposing parts where the first restricting protrusion and the second restricting protrusions do not face each other in the optical axis direction, the coil is formed by winding a conductor wire around the outer portion in a circumferential direction and includes first coil portions positioned in the protrusion opposing parts and second coil portions positioned in at least some of the non-opposing parts, and the width of the second coil portions in the optical axis direction is greater than the width of the first coil portions in the optical axis direction.