Camera Module Position Detection Using Dual Magnetic Sensors
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Solution Overview
Problem
Existing camera module position detection methods using magnetic sensors are inaccurate when the distance between the sensor and magnet varies, leading to unreliable two-dimensional position detection of the lens barrel, which is crucial for optical image stabilization.
Innovation Solution
The use of first and second magnetic sensors spaced apart by a predetermined distance on either side of the magnet allows for accurate detection of the magnet's position by summing their magnetic flux densities, maintaining a constant value regardless of the magnet's position, thereby reducing positional errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic sensor is disposed at a predetermined distance from a magnet to detect position, then the position can be detected, but the detection accuracy deteriorates when the distance between sensor and magnet varies
Solution Approach 1:
The patent divides the position detection function into two separate magnetic sensors positioned at predetermined distances from the magnet. Each sensor detects magnetic flux density at its specific location, and the position is determined by combining these two detection results. This segmentation allows the system to maintain accurate position detection even when the distance between sensors and magnet varies, as each sensor provides independent measurement data that can be processed together.
2Device complexity
If only one magnetic sensor is used to detect position, then the device complexity is reduced, but the measurement precision deteriorates due to inability to compensate for distance variations
Solution Approach 1:
The patent applies local quality by positioning two magnetic sensors at different predetermined distances from the magnet along the optical axis. Each sensor is optimized for detecting magnetic flux density at its specific location. The first sensor detects flux density at a first predetermined distance, while the second sensor detects at a second predetermined distance. This local optimization allows the system to compensate for distance variations and maintain high measurement precision without requiring complex additional components.
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 approach ensures accurate two-dimensional position detection of the lens barrel, minimizing errors and enhancing the reliability of optical image stabilization in camera modules.
Implementation Method 1
a magnetic sensor may be disposed spaced apart from a magnet that is used in moving a lens barrel by a predetermined distance, and the position of the lens barrel may be detected by a detection signal detected by the magnetic sensor
Data Source
Figure 1~3
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Figure 6A~6B
AI summary
Provided is a camera module including: a lens barrel (10) including at least one lens group (11); a moving frame (200) that includes the lens barrel, is movable in a first direction and in a second direction that is perpendicular to the first direction, and includes first and second magnets (211, 231) that are disposed on two sides in the first direction; a fixed frame (100) that movably supports the moving frame and includes first and second magnetic sensors (140, 150) that are spaced apart from each other in the first direction to respectively correspond to the first and second magnets; and a position information generating unit (3) that generates position information of the first and second magnets in the second direction based on a first detection signal detected by the first magnetic sensor and a second detection signal detected by the second magnetic sensor.