Magnetic Sensor Position Detection for Noise-Resistant Lens Positioning
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Solution Overview
Problem
Position detection devices using magnetic sensors are prone to errors in detection due to noise magnetic fields, leading to inaccurate lens positioning in autofocus mechanisms.
Innovation Solution
A position detection device utilizing a combination of first and second magnetic field generation units and sensors, with opposing magnetic field components, generates a sum of detection signals to mitigate noise interference, ensuring accurate position detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic sensor is used to detect lens position, then position detection is enabled, but noise magnetic fields cause errors in detection values
Solution Approach 1:
The detection system is divided into two independent position detectors (first and second), each detecting magnetic fields in different directions. This segmentation allows the system to separate the useful position information from noise interference by processing signals from multiple detection axes independently and then combining them.
Solution Approach 2:
The patent combines the detection signals from two independent position detectors to generate the final position detection signal. By merging the output signals from detectors oriented in different directions, the system achieves noise cancellation while preserving accurate position information.
2Ease of operation
If a single position sensor detects composite vector angle, then lens position can be detected, but noise magnetic fields cause changes in composite vector angle leading to detection errors
Solution Approach 1:
The patent transitions from single-dimension angle detection to two-dimensiona l position detection by adding a second position detector oriented perpendicular to the first. This dimensional expansion allows the system to resolve position information independently in two axes, making the detection less susceptible to noise that affects single-axis measurements.
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 device achieves high-accuracy position detection even in the presence of noise magnetic fields by reducing variations in detection signals, enhancing the precision of autofocus mechanisms.
Implementation Method 1
a magnetic sensor configured to detect a composite magnetic field generated by the first magnetic field and the second magnetic field and to generate a detection signal that varies in magnitude according to a direction of the composite magnetic field
Data Source
AI summary
A position detection device includes a first position detector, a second position detector, and a signal generator. The first position detector includes a first magnetic field generation unit, a second magnetic field generation unit, and a first magnetic sensor. The second position detector includes a third magnetic field generation unit, a fourth magnetic field generation unit, and a second magnetic sensor. The positions of the second and fourth magnetic field generation units vary in response to variations in a detection-target position. The signal generator generates a position detection signal, which is the sum of a first detection signal generated by the first magnetic sensor and a second detection signal generated by the second magnetic sensor. Each of the first and second position detectors includes a bias magnetic field generation unit.