Dual-Magnet Camera Module Autofocus for Precise Lens Stabilization
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Solution Overview
Problem
Current mobile electronic devices face challenges in achieving precise auto-focus and optical image stabilization, leading to suboptimal image quality due to limitations in actuator design and control mechanisms.
Innovation Solution
The implementation of a camera module with a housing containing a lens assembly and an auto-focus actuator, comprising magnets and coils, along with position sensors and driving circuits, allows for precise control of the lens movement along the optical axis, enabling both auto-focus and optical image stabilization functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single AF magnet and coil system is used, then the device complexity is reduced, but the focus precision and image stabilization accuracy deteriorate
Solution Approach 1:
The patent divides the single AF magnet into two separate magnets (first AF magnet and second AF magnet) positioned at opposite ends of the lens assembly. Each magnet has its own dedicated coil and position sensor, creating two independent control systems that work together to achieve precise focus adjustment and image stabilization without the interference present in single-magnet designs.
2Measurement precision
If dual AF magnets and coils are implemented, then focus precision and stabilization accuracy are improved, but the device complexity increases
Solution Approach 1:
The patent merges the functions of two separate control systems (focus adjustment and image stabilization) into a unified dual-magnet architecture. Both the first and second AF magnets are integrated onto the same lens assembly, sharing common structural support and working in coordination through a unified control circuit that processes position data from both sensors to achieve both focus precision and stabilization simultaneously.
Solution Approach 2:
The patent implements feedback control by using position sensors to continuously monitor the positions of both the first and second AF magnets. The control circuit receives real-time position data from both sensors and dynamically adjusts the current applied to each coil based on the detected positions, creating a closed-loop control system that maintains precise focus and stabilization despite variations in operating conditions.
3Measurement precision
If position sensors are added to detect magnet positions, then control accuracy is improved, but the manufacturing cost and device complexity increase
Solution Approach 1:
The position sensors in the patent serve multiple functions: they detect the positions of their respective AF magnets for both focus adjustment control and image stabilization control. The same sensors provide feedback for both operational modes, eliminating the need for separate sensing systems and reducing the overall component count despite the dual-magnet configuration.
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 solution enhances image capture quality by ensuring accurate focus and stabilization, reducing distortion and tilt, thereby improving the overall performance of mobile device cameras.
Implementation Method 1
a first AF coil disposed to face the first AF magnet, a first driving circuit including a first position sensor detecting a position of the first AF magnet and configured to control a current applied to the first AF coil
Data Source
AI summary
An electronic device is provided. The electronic device includes a housing, a lens assembly disposed along an optical axis, and an AF actuator. The AF actuator includes a first AF magnet disposed on a first surface of the lens assembly facing a first direction, a second AF magnet disposed on a second surface facing a direction opposite to the first direction with respect to the lens assembly, a first AF coil disposed inside the housing to face the first AF magnet, a first driving circuit disposed at the center of the first AF coil to control a current applied to the first AF coil, a second AF coil disposed inside the housing to face the second AF magnet, and a second driving circuit disposed at the center of the second AF coil to control a current applied to the second AF coil.