Lens Driving Magnet Layout for Tilt-Stable Auto Focus Feedback
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Solution Overview
Problem
Conventional camera modules with auto focus feedback functions suffer from static and dynamic tilts due to the sensing structure for the bobbin's position, affecting the precision of auto focus control.
Innovation Solution
A lens driving device is designed with a first magnet for sensing the bobbin's position and a second magnet establishing magnetic force equilibrium, along with a sensor part to provide precise auto focus and feedback functions, including a camera module and optical apparatus with a housing, bobbin, driving parts, and mounting components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single magnet is used for sensing the bobbin's position, then the sensing function is achieved, but static and dynamic tilts occur affecting auto focus precision
Solution Approach 1:
The patent introduces a second magnet as a counterbalancing element to the first magnet. The second magnet is positioned to create magnetic force equilibrium, counteracting the destabilizing magnetic forces generated by the first magnet during bobbin movement. This counterweight approach eliminates static and dynamic tilts while preserving position sensing capability through the sensor part.
2Extent of automation
If the sensing structure is added to achieve auto focus feedback, then auto focus feedback function is enabled, but static tilt and dynamic tilt are generated
Solution Approach 1:
The second magnet serves as a counterbalancing element that neutralizes the posture-disturbing effects of the sensing structure. By positioning the second magnet to establish magnetic force equilibrium with the first magnet, the system maintains bobbin stability while preserving the automated feedback function for precise auto focus control.
3Stability of the object's composition
If magnetic force equilibrium is established with two magnets, then static and dynamic tilts are reduced, but device complexity increases
Solution Approach 1:
The patent divides the magnetic system into two separate mounting parts: a first mounting part for the first magnet and a second mounting part for the second magnet. This segmentation allows independent positioning and adjustment of each magnet to achieve magnetic force equilibrium, thereby reducing tilts while maintaining manageable structural complexity through modular design.
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 reduces static and dynamic tilts, enhancing the precision of auto focus and optical image stabilization functions, leading to improved camera performance.
Implementation Method 1
a sensor part sensing a position of the first magnet
Implementation Method 2
a second magnet disposed on the second mounting part, wherein the second magnet establishes magnetic force equilibrium with the first magnet
Data Source
AI summary
A lens driving device is provided, the lens driving device including: a housing; a bobbin disposed at an inner side of the housing; a first driving part disposed on the bobbin; a second driving part disposed on the housing and facing the first driving part; a first mounting part disposed on the bobbin; a second mounting part disposed on the bobbin and disposed at an opposite side of the first mounting part based on a center of the bobbin; a first magnet disposed on the first mounting part; a sensor part sensing a position of the first magnet; and a second magnet disposed on the second mounting part.