Camera Actuator Layout for Compact OIS With Low Magnetic Interference
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Solution Overview
Problem
Existing camera modules face challenges in securing sufficient space for image stabilization actuators due to space constraints, magnetic interference between OIS and AF/zoom magnets, and posture differences leading to moment changes and energy inefficiency, particularly in ultra-slim and high-resolution designs.
Innovation Solution
A camera actuator design with a housing, mover, and driving part that includes magnets and coils, where magnets and coils are arranged to minimize interference and optimize space usage, with a tilting guide part to facilitate precise tilting and reduce magnetic field interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels in the image sensor is increased to improve resolution, then the resolution is improved, but the amount of light received per pixel decreases causing more severe image shake
Solution Approach 1:
The camera module is divided into functionally independent sub-modules: the OIS actuator for shake correction, the AF/zoom actuator for focusing and magnification, and the lens assembly. This segmentation allows each module to operate independently, enabling the OIS function to counteract image shake even when using high-resolution sensors with smaller pixels that receive less light.
2Object-affected harmful factors
If an actuator for OIS is disposed around the lens to correct image shake, then the image stabilization function is improved, but the space required for the actuator limits the size of the lens and increases module complexity
Solution Approach 1:
The OIS actuator and the AF/zoom actuator are merged into a single integrated actuator assembly. The OIS magnet and AF/zoom magnet are positioned in close proximity within the same housing structure, sharing common components such as the housing, mounting structures, and control circuitry. This merging reduces the overall volume required compared to having separate actuators, while still providing both OIS and AF/zoom functions.
Solution Approach 2:
The OIS magnet is positioned within the magnetic field region of the AF/zoom magnet, creating a nested configuration where the OIS actuator is effectively nested within the spatial envelope of the AF/zoom actuator. This nested arrangement allows both actuators to coexist in a compact volume, with the OIS magnet disposed between the AF/zoom magnet and the lens assembly.
3Volume of stationary object
If the OIS magnet and AF or zoom magnet are disposed close to each other to save space, then the module size is reduced, but magnetic field interference occurs between the magnets
Solution Approach 1:
A magnetic shield or flux director is positioned between the OIS magnet and the AF/zoom magnet to guide and separate their respective magnetic field lines. This intermediary structure channels the magnetic flux from each magnet along predetermined paths, preventing the magnetic fields from interfering with each other while allowing the magnets to remain in close proximity for compact design.
Solution Approach 2:
The magnetic field distribution is optimized by locally adjusting the geometry and material properties in different regions of the actuator assembly. The AF/zoom magnet and OIS magnet are designed with specific shapes and orientations that create localized magnetic field regions, and magnetic shielding materials are strategically placed in areas where field interference would be most problematic, allowing close spacing while minimizing interference.
4Device complexity
If a conventional actuator design is used, then the structure is simple, but posture differences cause large moment changes reducing energy efficiency
Solution Approach 1:
The actuator design incorporates adjustable parameters such as the position of the center of gravity, the orientation of the magnetic fields, and the geometry of the magnetic circuits. By optimizing these parameters, the actuator maintains a more consistent moment requirement across different posture angles, reducing the energy variations that would otherwise occur with conventional fixed designs. The magnetic field strength and direction can be dynamically adjusted to compensate for posture changes.
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
Enables accurate rotation driving, improved reliability, and energy efficiency, allowing for ultra-slim, ultra-small, and high-resolution cameras with stable OIS functionality without increasing module size and minimizing magnetic interference.
Implementation Method 1
a driving part disposed in the housing and configured to drive the mover, wherein the driving part includes at least one magnet and at least one coil
Implementation Method 2
the driving part includes at least one magnet and at least one coil
Data Source
AI summary
An embodiment of the present invention provides a camera actuator comprising: a housing; a mover disposed inside the housing and including an optical member; a tilting guide part for guiding tilting of the mover; and a driving part disposed inside the housing and driving the motor, wherein, the driving part comprises at least one magnet and at least one coil, and the at least one magnet at least partially overlaps the tilting guide part in a first direction perpendicular to an optical axis or in a second direction perpendicular to the optical axis.