Camera Module Movable Yoke Magnetic Flux Leakage
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Solution Overview
Problem
Camera module actuators face challenges in implementing optical image stabilization (OIS) due to magnetic flux leakage, which interferes with electronic components, unlike autofocusing (AF) actuators that can arrange yokes on the external side of the coil.
Innovation Solution
The camera module incorporates first and second movable yokes magnetized by coil portions, allowing movement perpendicular to the optical axis, with coil configurations and ball members to guide lens module movement and prevent magnetic flux leakage, using a housing with a focus adjustment and shake correction portion to maintain accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a yoke is arranged on the external side of the coil in an OIS actuator, then magnetic flux leakage is prevented, but the spacing between magnet and coil cannot be changed to implement OIS function
Solution Approach 1:
The yoke is divided into a fixed yoke and a movable yoke. The fixed yoke remains on the external side of the coil to prevent magnetic flux leakage, while the movable yoke can change spacing with the magnet to enable OIS function. This segmentation allows both functions to coexist without interference.
2Adaptability or versatility
If the spacing between magnet and coil is changed to implement OIS, then optical image stabilization is achieved, but magnetic flux leakage occurs causing interference with electronic components
Solution Approach 1:
The movable yoke acts as an intermediary between the magnet and the fixed yoke. It allows the magnet to move relative to the coil for OIS while maintaining magnetic flux containment through the yoke structure, preventing direct magnetic flux leakage to surrounding electronic components.
3Object-affected harmful factors
If a yoke is installed on the external side of the coil for AF actuator, then magnetic flux leakage is prevented, but the structure becomes more complex
Solution Approach 1:
The movable yoke serves multiple functions: it prevents magnetic flux leakage like a traditional yoke, enables OIS motion by changing spacing with the magnet, and provides a magnetic path for flux containment. This multi-functionality reduces the need for separate components and simplifies the overall structure.
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
This configuration effectively prevents magnetic flux leakage, enabling precise movement and positioning of the lens module for both focus adjustment and shake correction, enhancing image stability without interfering with electronic components.
Implementation Method 1
first and second movable yokes mounted on the lens module and first and second coil portions disposed to oppose the first and second movable yokes, respectively. The first coil portion is configured to attract the first movable yoke in response to power being applied to the first coil portion.
Implementation Method 2
The first and second movable yokes may be formed of a material magnetized by magnetic fields of the first and second coil portions.
Data Source
AI summary
A camera module includes: a housing in which a lens module is accommodated; and a shake correction portion including first and second movable yokes mounted on the lens module and first and second coil portions disposed to oppose the first and second movable yokes, respectively. The first coil portion is configured to attract the first movable yoke in response to power being applied to the first coil portion. The second coil portion is configured to attract the second movable yoke in response to power being applied to the second coil portion.