Lens Driving Device with Segmented Magnets for Multi-Axis OIS
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Solution Overview
Problem
Current lens driving devices face challenges with increased driving force requirements due to larger image sensors, rolling torque issues during optical image stabilization (OIS) operations, reliability problems from external impacts, component separation, high-frequency vibrations, and dynamic tilt due to spring structures, as well as magnetic field interference and complex driving order management for multi-axis OIS operations.
Innovation Solution
A lens driving device with a housing containing a lens assembly and magnets arranged at specific distances and orientations to manage movement around different rotation axes, along with a control unit that generates and sequences driving signals to optimize OIS operations based on movement detection and compensation angles, ensuring equal influence of each axis on Hall sensor output and minimizing cross-talk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the size of the image sensor is increased, then the image quality and stabilization performance are improved, but the driving force required for OIS operation increases
Solution Approach 1:
The magnet assembly is divided into multiple magnet parts (first magnet part, second magnet part, third magnet part) that can be independently controlled. Each magnet part corresponds to a specific coil part and works on a particular rotation axis, allowing the system to apply driving force only where needed rather than requiring all magnets to move simultaneously, thereby reducing the overall driving force requirement while maintaining image sensor stabilization performance.
Solution Approach 2:
The patent implements dynamic control of magnet parts based on detected shaking directions. The control unit selectively activates specific magnet parts corresponding to the detected shaking axis (pitch, yaw, or roll), rather than continuously activating all magnet parts. This dynamic activation pattern reduces the average driving force required while maintaining effective image stabilization across different shaking conditions.
2Reliability
If multiple magnet parts are used for multi-axis OIS operation, then the stabilization performance is improved, but magnetic field interference between magnets increases
Solution Approach 1:
The magnet assembly is segmented into multiple independent magnet parts, each associated with a specific rotation axis and coil part. This segmentation allows the system to activate only the necessary magnet parts based on the detected shaking direction, reducing the number of active magnetic fields in the system at any given time and thereby minimizing magnetic field interference between magnets.
Solution Approach 2:
The control unit acts as an intermediary that selectively activates specific magnet parts based on shaking detection. By controlling which magnet parts are active at any given time, the control unit prevents simultaneous activation of multiple magnet parts that could generate interfering magnetic fields, thus reducing magnetic field interference while maintaining stabilization performance.
3Productivity
If magnet parts are arranged at different distances from the rotation axis, then the movement range is optimized, but the influence on Hall sensor output becomes unequal causing cross-talk
Solution Approach 1:
The patent applies local quality by positioning each magnet part at a specific distance from the rotation axis center based on its functional requirements. The first magnet part is positioned at a first distance, the second magnet part at a second distance, and the third magnet part at a third distance, with each positioning optimized for its specific axis while maintaining equal influence on the Hall sensor output through coordinated control.
Solution Approach 2:
The control unit dynamically adjusts the driving parameters (current, voltage, activation timing) of each magnet part to compensate for their different distances from the rotation axis. By changing the driving parameters in proportion to the distance, the system ensures that each magnet part produces an equal influence on the Hall sensor output, eliminating cross-talk while maintaining optimal movement range for each axis.
4Reliability
If spring structures are used for lens support, then the shock absorption and reliability are improved, but high-frequency vibration and dynamic tilt occur
Solution Approach 1:
The patent replaces the mechanical spring support system with an electromagnetic driving system consisting of coil parts and magnet parts. Instead of relying on springs to provide both support and shock absorption, the system uses electromagnetic forces to actively control and stabilize the lens assembly position, thereby eliminating the high-frequency vibrations and dynamic tilt inherent in spring-based mechanical systems while maintaining shock absorption capability through active control.
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
Improves the accuracy and reliability of 3-axis OIS operations by ensuring equal movement distance and influence of each magnet part, reduces the force required for image sensor shift and tilt, prevents component separation, and optimizes image quality by minimizing dynamic tilt and vibrations.
Implementation Method 1
a lens driving device includes a first housing in which a lens assembly is disposed and a magnet is disposed; and a second housing in which a coil is disposed and disposed to surround the first housing
Data Source
AI summary
A lens driving device according to an embodiment can include a first housing in which a lens assembly is disposed therein and a magnet is disposed; and a second housing in which a coil is disposed and disposed to surround the first housing, wherein the magnet includes a plurality of magnet parts that move the lens assembly based on different rotation axes, and the plurality of magnet parts are arranged in the first housing to be spaced apart from a center of the rotation axis of the lens assembly at a same distance.