Lens Driving Module Damping and Hall Sensing for Fast Autofocus
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Solution Overview
Problem
The existing lens driving devices face challenges in accurately detecting the position of the bobbin and maintaining focus speed due to internal space constraints and vibration issues in miniaturized camera modules, leading to reduced auto-focusing speed and instability in feedback control.
Innovation Solution
A lens driving device is designed with a damping member and support unit that minimizes distortion and damage, allowing for efficient assembly and improved product usability, featuring a detection unit with a Hall sensor for precise position detection and a damping member to stabilize phase shift and reduce resonant frequency peaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the camera module is miniaturized to reduce size, then the internal space is reduced, but the position detection accuracy and focus control stability deteriorate
Solution Approach 1:
The patent replaces mechanical position detection mechanisms with a magnetic field-based detection system using Hall sensors. This substitution allows for accurate position detection without requiring large mechanical structures, thereby maintaining detection precision while enabling camera module miniaturization.
Solution Approach 2:
The patent changes the detection parameter from mechanical displacement to magnetic field strength variations. By detecting changes in magnetic field strength caused by bobbin movement, the system achieves accurate position detection in a compact form factor, resolving the contradiction between miniaturization and detection accuracy.
2Volume of moving object
If the elastic member is designed for miniaturization, then the internal space is reduced, but the vibration frequency increases causing control instability
Solution Approach 1:
The patent converts the harmful high-frequency vibrations caused by miniaturized elastic members into beneficial damping effects. By strategically placing damping members at vibration nodes, the system utilizes the high-frequency vibrations to enhance damping efficiency, thereby stabilizing feedback control while maintaining miniaturization benefits.
Solution Approach 2:
The patent introduces damping members as intermediary elements between the miniaturized elastic member and the bobbin. These damping members act as mediators that absorb and dissipate vibration energy, preventing control instability while allowing the elastic member to remain miniaturized for compact design.
3Loss of time
If the driver scrambling is increased to improve response, then the setting time is reduced, but the auto-focusing speed decreases
Solution Approach 1:
The patent applies damping material selectively at specific locations (vibration nodes) rather than uniformly throughout the structure. This localized application provides effective vibration control and optimal setting time without adding excessive mass that would reduce auto-focusing speed, thereby resolving the contradiction between response time and focusing speed.
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 solution enhances the accuracy of position detection and auto-focus speed, stabilizes feedback control, and reduces product faults and assembly complexity, while maintaining the structural integrity of miniaturized camera modules.
Implementation Method 1
A lens driving device is designed with a damping member and support unit that minimizes distortion and damage, allowing for efficient assembly and improved product usability, featuring a detection unit with a Hall sensor for precise position detection
Implementation Method 2
a damping member to stabilize phase shift and reduce resonant frequency peaks
Implementation Method 3
an elastic member coupled to the bobbin and the housing
Implementation Method 4
The VCM operates by an electromagnetic interaction between a magnet fixed in a housing and a coil unit wound on an outer circumferential surface of a bobbin coupled with a lens barrel
Data Source
AI summary
A lens driving device is provided, including: a cover member; a bobbin installed with at least one lens and having a coil unit arranged on an outer circumferential surface of the bobbin; a magnet arranged at a positon corresponding to that of the coil unit; first and second elastic members, where one end of each of the first and second elastic members may be respectively coupled to an upper surface and a lower surface of the bobbin and supporting movement of the bobbin in an optical axis direction; a detection unit configured to detect movement of the bobbin in a direction parallel to the optical axis direction; a damping member arranged at a connecting portion between the bobbin and the first elastic member; and a support unit provided at at least one of the bobbin and the first elastic member and maintaining an arranged position of the damping member.