Lens Driving Device Leaf Spring Torsional Rigidity Reduction
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Solution Overview
Problem
Existing lens driving devices are prone to suspension wire breakage when subjected to impacts in directions other than the optical axis, due to the high torsional rigidity of buckling prevention parts, which concentrates stress on the wires rather than the parts themselves.
Innovation Solution
A lens driving device with a leaf spring design featuring torsionally deformable first and second beams, formed as a monolithic component, that disperses stress by reducing torsional rigidity at the wire fixing points, allowing the suspension wires to deform and preventing breakage during impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If buckling prevention parts are made with high torsional rigidity to prevent wire buckling in optical axis direction, then buckling prevention capability is improved, but stress concentration on suspension wires occurs during twisting impacts
Solution Approach 1:
The leaf spring is designed with non-uniform thickness distribution, featuring a thicker spring body portion for overall support and thinner beam portions (first and second beams) at the wire fixing part. This local quality variation allows the spring body to provide buckling prevention while the thinner beams reduce torsional rigidity at the wire connection points, preventing stress concentration on the suspension wires during twisting impacts.
2Reliability
If plate-shaped buckling prevention parts are used to deform elastically in optical axis direction, then wire buckling is prevented, but torsional rigidity remains high causing wire breakage
Solution Approach 1:
The invention changes the geometric parameters of the leaf spring by introducing varying thickness along its length. The spring body has a first thickness while the beams have a second thickness smaller than the first. This parameter change enables the spring to maintain sufficient elastic deformation capability in the optical axis direction while reducing torsional rigidity at critical wire connection points, preventing wire breakage during twisting impacts.
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
The design effectively reduces the risk of suspension wire breakage and fatigue by distributing torsional forces, ensuring the lens driving device can withstand external impacts without damaging the suspension wires.
Implementation Method 1
a first beam and a second beam that are disposed between the spring body and the wire fixing part and torsionally deformable
Data Source
AI summary
A lens driving device includes a base, a lens holder capable of holding a lens body, a movable support, a leaf spring that is disposed on the movable support and supports the lens holder such that the lens holder is movable along an optical axis of the lens body, a suspension wire that rises from the base along the optical axis and supports the movable support such that the movable support is movable in a direction intersecting the optical axis, and a drive mechanism that moves the movable support in the direction intersecting the optical axis. The leaf spring includes a spring body fixed to the movable support, a wire fixing part to which the suspension wire is fixed, and a first beam and a second beam that are disposed between the spring body and the wire fixing part and torsionally deformable.