Camera Actuator Nested Magnet Coil Design for OIS
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Solution Overview
Problem
Camera actuators face challenges in implementing a long stroke and miniaturization while maintaining high driving efficiency and coupling strength between driving magnets, especially in ultra-slim and ultra-small devices with high pixel density, where space constraints limit lens size and increase magnetic field interference.
Innovation Solution
A camera actuator design featuring a housing with a driving unit that includes a driving coil and magnet, where the magnet is positioned between the coil and the lens assembly, and a ball unit facilitates movement, allowing for adjustable positions of the driving magnet and coil to achieve a long stroke and high driving efficiency, while minimizing counter electromotive force and magnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the actuator for OIS is disposed around the lens to enable optical image stabilization, then the lens can tilt or move to correct image shake, but the space required for the actuator limits the lens size and increases device complexity
Solution Approach 1:
The patent positions the driving magnet and driving coil such that the magnet is located between the coil and the lens assembly, utilizing the optical axis direction (Z-axis) for arrangement. This spatial reconfiguration allows the actuator components to be stacked along the optical path rather than disposed radially around the lens, enabling OIS functionality while maintaining a compact lens diameter and reducing overall device volume.
2Measurement precision
If the pixel density of the image sensor is increased to improve resolution, then the image quality improves, but the amount of light received decreases and hand shaking becomes more severe
Solution Approach 1:
The patent implements an optical image stabilization mechanism that uses electromagnetic actuation (driving coil and magnet interaction) to physically move the lens assembly for correcting image shake. This mechanical compensation system counteracts the harmful effects of hand shaking that become more severe with high pixel density sensors, allowing the camera to maintain both high resolution and stability.
3Object-generated harmful factors
If the driving coil is spaced apart from the driving magnet in the optical axis direction to reduce interference, then magnetic field interference decreases, but counter electromotive force increases and driving efficiency decreases
Solution Approach 1:
The patent optimizes the spacing parameter between the driving coil and driving magnet along the optical axis. By carefully controlling this distance, the design achieves a balance where magnetic field interference with other components (such as AF or zoom magnets) is sufficiently reduced, while the counter electromotive force remains at acceptable levels to maintain driving efficiency. This parameter optimization allows the actuator to function effectively in a compact configuration.
4Volume of moving object
If the camera device is miniaturized to meet ultra-slim requirements, then the device size decreases, but the space for arranging actuators and lenses is severely constrained
Solution Approach 1:
The patent arranges the driving magnet and driving coil in a nested configuration where the magnet is positioned between the coil and the lens assembly. This nested layout allows multiple functional components (actuator, lens, and mounting structures) to be compactly integrated along the optical axis, achieving ultra-slim device dimensions while maintaining all necessary functional spaces for OIS operation.
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 solution enables a camera actuator with improved reliability and increased moving distance for auto focusing, supporting high-magnification zoom and reducing counter electromotive force, thus enhancing the camera's performance in compact devices.
Implementation Method 1
a driving unit configured to move the first lens assembly and the second lens assembly, wherein the driving unit includes a driving coil and a driving magnet facing the driving coil
Implementation Method 2
a ball unit disposed between the first lens assembly and the housing and between the second lens assembly and the housing
Data Source
AI summary
An embodiment of the present invention provides a camera actuator comprising: a housing; a first lens assembly and a second lens assembly which are moved in the optical axis direction on the basis of the housing; a driver which moves the first lens assembly and the second lens assembly; and ball portions arranged between the first lens assembly and the housing and between the second lens assembly and the housing, wherein the driver comprises: a driving coil; and a driving magnet facing the driving coil, and the driving magnet comprises: an upper magnet; and a lower magnet arranged on the lower portion of the upper magnet. The driving coil comprises: an upper coil facing the upper magnet; and a lower coil facing the lower magnet, and the upper magnet and the lower magnet are arranged between the upper coil and the lower coil and are coupled to one of the first lens assembly and the second lens assembly.