Lens Actuator Magnetic Layout for Barrel Stability and Sensitivity
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Solution Overview
Problem
Existing lens driving devices utilize a single open-loop magnetic circuit system, resulting in ineffective mass distribution during lens assembly movement, leading to reduced sensitivity and increased risk of failure.
Innovation Solution
A closed-loop magnetic circuit system is implemented, with first and second driving assemblies arranged diagonally on the first bracket, and stabilization coils fixed to the bottom plate, reducing the total mass of the lens assembly's movement along the optical axis while enhancing sensitivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single open-loop magnetic circuit system is used, then the device complexity is reduced, but the sensitivity and reliability of lens assembly movement control deteriorates
Solution Approach 1:
The patent divides the magnetic circuit system into two separate closed-loop magnetic circuit systems (first and second magnetic circuit systems), each independently controlling different aspects of lens assembly movement. This segmentation improves control reliability by eliminating the weaknesses of a single open-loop system while managing complexity through modular design.
2Measurement precision
If the driving coil extends to the outer side of the magnetic yoke via notches, then the mass distribution is optimized for sensitivity, but the manufacturing precision requirements increase
Solution Approach 1:
The notches are pre-formed in the magnetic yoke at specific positions during manufacturing, establishing predetermined pathways for the driving coil. This preliminary action ensures accurate coil positioning and optimal mass distribution for sensitivity without requiring high-precision assembly operations, thus managing manufacturing precision requirements.
3Stability of the object's composition
If stabilization coils are fixed to the bottom plate, then the swing mode suppression is improved, but the device complexity increases
Solution Approach 1:
The stabilization coils are integrated with the first magnetic circuit system and shared magnetic circuit components, merging the stabilization function with the existing driving structure. This reduces the overall device complexity compared to having completely separate stabilization systems, while still achieving effective swing mode suppression.
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 closed-loop magnetic circuit system reduces the total mass of the lens assembly's movement, improving sensitivity and reducing the risk of failure, while the stabilization coils balance the mass to suppress swing modes.
Implementation Method 1
a first driving assembly, wherein two first driving assemblies are provided and arranged at a set of diagonal positions of the first bracket and configured to drive the second bracket to move along a direction of an optical axis of the lens assembly; the first driving assembly includes a first magnetic circuit system fixed to the first bracket and a driving coil fixed to the second bracket
Implementation Method 2
a second driving assembly configured to drive the second bracket to move along a direction perpendicular to the optical axis of the lens assembly, wherein the second driving assembly includes a second magnetic circuit system fixed to the bottom plate and an stabilization coil fixed to the first bracket
Data Source
AI summary
A lens driving device, including: a shell including a bottom plate and an upper cover; a first bracket elastically supported at the bottom plate; a second bracket elastically supported at the first bracket and for mounting a lens assembly; a first driving assembly, two first driving assemblies being provided and configured to drive the lens assembly to move, and the first driving assembly including a first magnetic circuit system fixed to the first bracket and a driving coil fixed to the second bracket; and a second driving assembly configured to drive the second bracket to move, and including a second magnetic circuit system fixed to the bottom plate and an stabilization coil fixed to the first bracket. The lens driving device reduces a risk of falling failure of a barrel of the lens assembly, and suppresses a swinging mode of the barrel of the lens assembly.