Voice Coil Motor Bobbin Coupling for Precise Lens Gap Stability
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Solution Overview
Problem
Conventional voice coil motors (VCMs) used in small digital cameras face challenges in accurately adjusting the gap between the lens and image sensor due to manufacturing tolerances, leading to reduced image quality and increased manufacturing costs, with issues such as elastic member disengagement from the bobbin under external shocks or vibrations, and inadequate coupling strength between the coil and elastic members.
Innovation Solution
A VCM design featuring a bobbin with upper and lower protrusions, a coil block, and elastic members with specific through holes and coupling units, along with adhesive guide lugs to enhance coupling strength and prevent disengagement, using thermal fusion and adhesive reinforcement to secure the elastic members to the bobbin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the elastic member is coupled to the bobbin using conventional methods (insert method or thermal fusion), then the manufacturing process becomes complicated or the coupling strength is insufficient, but the manufacturing cost increases or the elastic member disengages under vibration and shock
Solution Approach 1:
The elastic member is divided into multiple segments with coupling protrusions that engage with corresponding coupling grooves on the bobbin. This segmentation allows for simple snap-fit assembly without complex manufacturing processes while ensuring reliable coupling strength to prevent disengagement under vibration and shock.
2Manufacturing precision
If manufacturing tolerances are not严格控制, then the manufacturing cost is reduced, but gaps are generated between the bobbin and elastic member making it difficult to accurately adjust the interval between lens and image sensor
Solution Approach 1:
The elastic member incorporates flexible adjustment mechanisms that allow dynamic tuning of the gap between the lens and image sensor after assembly. This enables precise gap adjustment without requiring extremely tight manufacturing tolerances, thereby reducing manufacturing costs while maintaining high precision.
3Power
If the coil block is tightly coupled to the bobbin, then the magnetic field generation is improved, but the heat dissipation becomes insufficient
Solution Approach 1:
The coil block features localized coupling regions with varying degrees of tightness. Critical areas for magnetic field generation have strong coupling, while regions requiring heat dissipation have optimized thermal pathways with appropriate clearance. This local quality differentiation maintains high power efficiency while ensuring effective heat dissipation.
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 ensures accurate adjustment of the lens and image sensor gap, increases reliability by preventing elastic member disengagement, and reduces manufacturing costs by improving coupling strength and durability.
Implementation Method 1
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
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 3
an elastic member elastically supporting a magnet opposite to the coil block and 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.