Camera Module Yoke Structure for OIS Flux Leakage Control
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Solution Overview
Problem
Existing camera module actuators for optical image stabilization (OIS) suffer from magnetic flux leakage, which affects the performance and efficiency of the OIS operation.
Innovation Solution
The camera module incorporates a design with a yoke installed on both the fixed and movable bodies, and a coil positioned to face the yoke, along with an elastic member providing restorative force. This configuration prevents magnetic flux leakage and enhances the reluctance force for efficient OIS operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a coil and permanent magnet are disposed similarly to the AF actuator for OIS operation, then the OIS function can be implemented, but magnetic flux leaks externally causing performance degradation
Solution Approach 1:
A yoke is introduced as an intermediary component between the coil and external environment. The yoke serves as a magnetic flux guide that channels the magnetic field lines through a defined path, preventing direct leakage into the surrounding space while maintaining the electromagnetic interaction necessary for OIS operation.
Solution Approach 2:
The harmful magnetic flux leakage is extracted and redirected through the yoke structure. By providing a dedicated magnetic path, the unwanted external magnetic field interaction is separated from the functional electromagnetic drive, isolating the harmful effect while preserving the useful OIS function.
2Force
If a yoke is attached to the external surface of the coil to increase generated force and prevent magnetic flux leakage, then the electromagnetic force is enhanced, but the device complexity increases
Solution Approach 1:
The yoke is designed to perform multiple functions simultaneously: it acts as a magnetic flux guide to prevent leakage, provides structural support for the coil assembly, and serves as a mounting platform for the permanent magnet. This multi-functionality increases force generation while minimizing the addition of separate components.
Solution Approach 2:
The yoke structure is integrated with the existing actuator components rather than being added as a separate external element. The coil is wound around or mounted on the yoke, and the permanent magnet is positioned in relation to the yoke geometry, merging these elements into a unified assembly that reduces overall structural complexity.
3Device complexity
If the actuator is driven back and forth for OIS operation without a yoke, then the structure is simpler, but magnetic flux leaks externally affecting performance
Solution Approach 1:
The yoke serves as a necessary intermediary component that enables reliable OIS operation by controlling magnetic flux containment. Without this mediating structure, the magnetic field would leak uncontrollably, causing performance degradation and unreliable stabilization function.
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 proposed solution effectively prevents magnetic flux leakage, improves the reliability of OIS operations, and reduces magnetoresistance, leading to enhanced camera module performance.
Implementation Method 1
drive the lens barrel upwardly and downwardly by generating electromagnetic force through an interaction between an internal permanent magnet and the outer coil
Implementation Method 2
A yoke is attached to an external surface of the coil to increase the generated force and prevent external magnetic flux leakage
Implementation Method 3
an elastic member connected to the fixed body and the first movable body and configured to provide a restorative force to the first movable body
Data Source
AI summary
A camera module is provided. The camera module includes a fixed body which has an internal space; a first movable body movably disposed on the fixed body; a substrate disposed on the first movable body, and on which an image sensor is mounted; a yoke disposed on one of the fixed body and the first movable body; a coil disposed on the other of the fixed body and the first movable body, and disposed to face the yoke; and an elastic member connected to the fixed body and the first movable body, and configured to provide a restorative force to the first movable body.