Camera Module Suspension Wire Buckling Prevention
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Solution Overview
Problem
Existing camera modules with image stabilizing functions face challenges in drop impact resistance due to the susceptibility of suspension wires to buckling and permanent deformation, as they are flexible in directions perpendicular to their longitudinal axis and have limited deformation tolerance in the longitudinal direction.
Innovation Solution
A camera module configuration that includes a lens drive device with suspension wires supported by an elastic body and a locking member, where the suspension wire and elastic body have spring constants set to prevent stress from exceeding the buckling and yield stresses, thereby controlling the deformation amount and reducing the risk of buckling and permanent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If suspension wires are used to support the movable section in the image stabilizing mechanism, then the movable section can be driven in directions perpendicular to the optical axis, but the suspension wires are susceptible to buckling and permanent deformation under drop impact
Solution Approach 1:
The support system is segmented into multiple suspension wires (typically four) arranged symmetrically around the optical axis. Each wire independently supports the movable section, distributing the mechanical load and reducing the stress on any single wire during impact events.
Solution Approach 2:
The patent introduces a shock-absorbing structure positioned between the movable section and the fixed section. This structure includes a shock-absorbing member that elastically deforms to absorb impact energy before it reaches the suspension wires, preventing buckling and permanent deformation during drop impacts.
2Adaptability or versatility
If the suspension wire is made flexible in directions perpendicular to its longitudinal axis, then the movable section can move freely, but the deformation tolerance in the longitudinal direction is extremely small
Solution Approach 1:
The suspension wires are designed with anisotropic mechanical properties: highly flexible in radial directions (perpendicular to longitudinal axis) to enable free movement of the movable section, but with sufficient longitudinal strength to resist buckling under compressive loads during impact. This is achieved through careful selection of wire material and diameter.
Solution Approach 2:
The shock-absorbing structure is positioned to engage before the suspension wires experience compressive loads that would cause buckling. The shock-absorbing member deforms elastically to absorb impact energy, preventing the suspension wires from exceeding their longitudinal deformation tolerance.
3Adaptability or versatility
If the image stabilizing function is added to mobile phone camera modules, then advanced imaging capability is achieved, but the device size increases
Solution Approach 1:
The image stabilizing mechanism is nested within the existing lens drive device structure. The movable section that holds the lens is integrated with the stabilization mechanism, and the shock-absorbing structure is positioned within the annular space between the movable and fixed sections. This nested arrangement minimizes the overall volume increase while providing full image stabilizing functionality.
Solution Approach 2:
The shock-absorbing structure utilizes an elastic body that can be formed as a thin-walled structure or flexible component. This allows the shock-absorbing element to provide sufficient cushioning while occupying minimal space within the compact camera module architecture.
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 buckling and permanent deformation of suspension wires, enhancing the drop impact resistance of the camera module by distributing deformation across the suspension wire and elastic body, ensuring the stress remains within safe limits.
Implementation Method 1
an elastic body which is connected to at least one end of the suspension wire and prevents buckling and permanent deformation of the suspension wire
Implementation Method 2
the suspension wire and the elastic body each having a spring constant that is set so that a maximum value of stress does not exceed buckling stress and yield stress of the suspension wire
Data Source
AI summary
A camera module (50) is provided with a suspension wire (16) and an AF spring. The spring constant of the suspension wire (16) and the AF spring is set so that the maximum value of stress specified according to the degree of deformation in the longitudinal direction of the suspension wire (16) does not exceed the buckling stress or the yield stress of the suspension wire (16) when a movable section moves within a moving range.