Voice Coil Motor Elastic Coupling for Precise Lens Gap Control
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Solution Overview
Problem
Conventional voice coil motors (VCMs) face challenges in accurately adjusting the gap between a lens and an image sensor due to manufacturing tolerances, leading to reliability issues and increased manufacturing costs.
Innovation Solution
The proposed VCM design includes a bobbin with protrusions, a coil block, a magnet, and elastic members with specific structural features such as adhesive guide lugs and thermal fusion units to enhance coupling strength and prevent disengagement from vibrations or shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manufacturing methods are used for the bobbin and elastic member, then manufacturing cost is reduced, but a gap is generated between the bobbin and elastic member due to manufacturing tolerance, making it difficult to accurately adjust the lens-image sensor interval
Solution Approach 1:
The patent applies preliminary action by pre-forming protrusions on the bobbin and corresponding recesses on the elastic member during the manufacturing process. These coupling features are created in advance to eliminate gaps caused by manufacturing tolerances, ensuring accurate lens-image sensor interval adjustment without requiring additional post-assembly adjustments or increasing manufacturing complexity.
2Reliability
If the elastic member is simply supported by the bobbin without coupling features, then the device complexity is reduced, but the elastic member may disengage due to vibrations or shocks
Solution Approach 1:
The patent merges the coupling function into the existing bobbin and elastic member structures by integrating protrusions and recesses directly into these components. This combination approach provides reliable elastic member coupling that prevents disengagement from vibrations or shocks without introducing separate coupling mechanisms, thereby maintaining device simplicity while enhancing reliability.
3Strength
If adhesive is used to couple the elastic member to the bobbin, then coupling strength is improved, but manufacturing process becomes more complex and adhesive application precision is difficult to control
Solution Approach 1:
The patent replaces the chemical bonding mechanism (adhesive) with a mechanical coupling system consisting of protrusions and recesses. This mechanical substitution provides inherent coupling strength through the interlocking geometry of the features, eliminating the need for adhesive application processes and their associated complexity while maintaining or improving coupling strength.
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 design effectively reduces manufacturing costs, enhances reliability by preventing elastic member disengagement, and improves the coupling power between the coil and the elastic member, allowing for accurate adjustment of the lens-image sensor interval.
Implementation Method 1
a VCM (voice coil motor) on a wide range base... The VCM is a motor that uses a force from a magnetic field generated by a magnet and a magnetic field generated by a coil block facing the magnet
Implementation Method 2
an elastic member elastically supporting a magnet opposite to the coil block and the bobbin... the elastic member is coupled to a boss protruded from a bottom distal end of the bobbin
Data Source
AI summary
A VCM (voice coil motor) is disclosed, the VCM including: a rotor including a cylindrical bobbin for accommodating a lens and protruded at a bottom end with a boss, and a coil block arranged at a periphery of the bobbin; a stator including a magnet facing the coil block and a yoke fixing the magnet; and an elastic member including a first elastic member formed with a through hole coupled to the boss of the bobbin and a second elastic member coupled to an upper end facing the bottom end of the bobbin; wherein the boss is formed with a disengagement prevention unit inhibiting the first elastic member from being disengaged from the boss, and the first elastic member is formed with a coupling unit contacting a joint where the disengagement prevention unit and the coupling unit meet.