Lens Drive Magnet Layout for AF Force and Low Magnetic Interference
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Solution Overview
Problem
Existing lens moving apparatuses face challenges in securing AF driving force while minimizing magnetic field interference with adjacent components.
Innovation Solution
A lens moving apparatus design featuring a housing, bobbin, coil, magnet, and yoke configuration with specific recesses and asymmetrical placement to reduce magnetic interference, ensuring AF driving force is maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the magnet is positioned centrally to maximize AF driving force, then the autofocus driving capability is improved, but magnetic field interference with adjacent lens moving apparatus increases
Solution Approach 1:
The magnet is intentionally positioned asymmetrically with its center line offset from the baseline by a distance K (0 < K ≤ 0.5 mm). This asymmetric positioning shifts the magnet away from the center, reducing magnetic field interference with adjacent lens moving apparatus while maintaining sufficient overlap with the coil to preserve autofocus driving force.
2Object-affected harmful factors
If the magnet is offset from center to reduce magnetic field interference, then magnetic field interference with adjacent components is reduced, but AF driving force may be compromised
Solution Approach 1:
The offset distance K is carefully controlled within a specific range (0 < K ≤ 0.5 mm). This parameter optimization ensures that the magnet is sufficiently offset to reduce magnetic field interference while maintaining adequate overlap with the coil to preserve autofocus driving force. The yoke center line is also positioned within 0-0.5 mm from the magnet center line to optimize magnetic flux distribution.
Solution Approach 2:
The yoke structure acts as an intermediary to guide and concentrate magnetic flux from the asymmetrically positioned magnet toward the coil. The yoke's extension portions are strategically positioned to ensure efficient magnetic coupling despite the magnet's offset location, thereby maintaining AF driving force while allowing the magnet to be positioned away from the center to reduce interference.
3Object-affected harmful factors
If recesses are added to the magnet structure to optimize magnetic field distribution, then magnetic field interference is reduced, but manufacturing complexity increases
Solution Approach 1:
The magnet structure is segmented by adding first and second recesses at its ends. These recesses divide the magnet's magnetic field distribution, creating regions of different magnetic field strength. This segmentation allows optimization of magnetic field interference reduction while maintaining a relatively simple manufacturing process through standard machining operations.
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 design secures AF driving force and reduces magnetic field interference with adjacent lens moving apparatuses, enhancing operational stability and performance.
Implementation Method 1
a coil disposed at the bobbin, a magnet disposed at the side portion of the housing
Data Source
AI summary
An embodiment comprises: a housing; a bobbin disposed in the housing; a coil disposed on the bobbin; a magnet disposed in a side portion of the housing, and including a first side surface facing the coil and a second side surface opposite to the first side surface; and a yoke disposed in the upper portion of the housing and overlapping the magnet in the optical axis direction, wherein: the centerline of the magnet is located on one side with reference to a reference line; a first groove adjoining one end of the first side surface of the magnet is disposed at a first end of the magnet; a second groove adjoining the other end of the first side surface of the magnet is disposed at a second end of the magnet; the reference line passes through the center of the housing and is perpendicular to the outer surface of the side portion of the housing where the magnet is disposed; and the centerline of the magnet is a straight line passing through the center between the first end and the second end of the magnet and perpendicular to the first side surface of the magnet.