Lens Driving Module Damping for Stable Autofocus Feedback
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Solution Overview
Problem
The existing lens driving devices face challenges in miniaturization due to limited internal space in camera modules, leading to issues with vibration frequency and auto-focus speed, particularly in detecting the optimal focus position and stabilizing 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 bobbin with a coil unit, elastic members, and a detection unit for accurate position feedback, which stabilizes phase shift and reduces 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 vibration frequency of elastic members increases causing control problems
Solution Approach 1:
A damping member is introduced as an intermediary element between the elastic member and the bobbin/holder member. This damping member absorbs and dissipates vibration energy, acting as a mediator that reduces the harmful vibration frequency effects caused by miniaturization while allowing the compact camera module design to be maintained.
2Length of moving object
If the lens driving distance is increased to improve focus range, then the auto-focus speed decreases due to excessive driver scrambling
Solution Approach 1:
The damping member serves as an intermediary that suppresses driver scrambling vibrations during the lens driving process. By reducing these vibrations, the damping member enables smoother and faster lens movement over longer distances, thereby improving auto-focus speed while maintaining the required lens driving distance.
3Volume of moving object
If elastic members are designed to fit narrow internal spaces, then the camera module size is reduced, but vibration control and feedback stability deteriorate
Solution Approach 1:
The damping member is positioned between the elastic member and the bobbin/holder member to act as a vibration-damping intermediary. This allows the elastic member to be designed in a compact form suitable for narrow internal spaces while the damping member compensates for the increased vibration, maintaining feedback control stability.
4Measurement precision
If the bobbin position detection accuracy is improved for precise auto-focus, then the feedback control complexity increases
Solution Approach 1:
A detection unit is implemented to provide accurate position information of the bobbin as feedback to the control system. This feedback mechanism enables precise auto-focus control by continuously monitoring the bobbin position and adjusting the driving force accordingly, improving measurement precision while managing feedback control complexity through systematic implementation.
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 and speed of auto-focus operations, improves the stability of feedback control, and reduces the occurrence of product faults during manufacturing, while maintaining the compact size required for miniaturized camera modules.
Implementation Method 1
a damping member contacting the bobbin and the elastic member
Implementation Method 2
reduces resonant frequency peaks and stabilizes phase shift
Implementation Method 3
a bobbin being moved in upward and downward directions is elastically supported by an upper and a first elastic member
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
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.