Magnetic Field Measuring Device Using Convergence Plates
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Solution Overview
Problem
Magnetic field sensors face challenges in detecting the position, movement, or rotation of objects with low magnetic field strength and high magnetic noise disturbance, leading to increased jitter and inaccurate output duty.
Innovation Solution
A magnetic field measuring device utilizing first to fourth magnetoelectric transducers and magnetic convergence plates to convert horizontal magnetic field vectors into vertical vectors, combined with a calculation unit that adds or subtracts outputs to eliminate noise and achieve low-jitter, accurate duty cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic field sensors are used to detect position, movement, or rotation, then detection capability is provided, but magnetic noise disturbance increases and output jitter increases at low magnetic field strengths
Solution Approach 1:
The sensor is divided into multiple Hall ICs (first Hall IC and second Hall IC) with different sensitivities. The first Hall IC has high sensitivity for detecting weak magnetic fields, while the second Hall IC has low sensitivity for rejecting magnetic noise. By segmenting the detection function into separate sensors with different characteristics, the system can simultaneously achieve accurate detection at low field strengths and immunity to magnetic noise disturbance.
Solution Approach 2:
Different parts of the sensor system are given different local qualities - the first Hall IC is optimized for high sensitivity to detect weak magnetic fields, while the second Hall IC is optimized for low sensitivity to reject magnetic noise. This local differentiation allows each component to perform its specific function optimally, resolving the contradiction between detection accuracy and noise rejection.
2Measurement precision
If magnetic field strength is increased for better detection, then detection accuracy improves, but magnetic noise disturbance also increases
Solution Approach 1:
The detection system is segmented into two parallel Hall IC paths with different sensitivity characteristics. The high-sensitivity path captures the signal, while the low-sensitivity path captures only the noise floor. By segmenting the measurement function this way, the system can accurately detect weak fields without being overwhelmed by magnetic noise disturbance.
Solution Approach 2:
The second Hall IC acts as an intermediary reference that measures the magnetic noise disturbance level. This intermediary measurement allows the system to compensate for or reject the magnetic noise disturbance from the first Hall IC's output, enabling accurate detection even when magnetic field strength is low.
3Measurement precision
If output jitter is reduced for accurate duty cycles, then measurement precision improves, but device complexity increases
Solution Approach 1:
The sensor is segmented into multiple Hall ICs with different sensitivity characteristics, which increases device complexity. However, this segmentation enables the system to reduce output jitter by using the low-sensitivity Hall IC to reject magnetic noise disturbance, thereby achieving accurate duty cycle detection.
Solution Approach 2:
The system changes the sensitivity parameter of different Hall ICs to create a contrast between signal detection capability and noise rejection capability. By adjusting the sensitivity parameters of the individual Hall ICs, the system achieves low jitter output while maintaining the necessary detection accuracy.
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 effectively eliminates magnetic noise disturbance and provides low-jitter, accurate output even at low magnetic field strengths, enhancing the detection of position, movement, or rotation of objects.
Implementation Method 1
magnetic convergence plates made up of a magnetic body... convert magnetic field vectors produced in a horizontal direction with respect to the magneto-sensing surface... into magnetic field vectors in a vertical direction
Implementation Method 2
first to fourth magnetoelectric transducers... detect the strength of a magnetic field produced from a magnetic field-producing body
Data Source
Figure 1A~1C
Figure 2
Figure 3
AI summary
The present invention provides a magnetic field measuring device that provides accurate output according to a magnetic field fromamultipolarmagnet in an environment of large magnetic field disturbance. The magnetic field measuring device comprises first to fourthmagnetoelectric transducers, magnetic convergence plates, and a calculation unit that calculates the strength of a magnetic field applied in a horizontal direction and/or a vertical direction with respect to a magneto-sensing surface of the magnetoelectric transducers,wherein the magnetic convergence plates are placed so as to convert magnetic field vectors produced in a horizontal direction with respect to the magneto-sensing surfaces of the first and second magnetoelectric transducers into magnetic field vectors in a vertical direction with respect to the magneto-sensing surfaces of the first and second magnetoelectric transducers, and also in opposite directions at eachmagneto-sensing surface, and convert magnetic field vectors produced in a horizontal direction with respect to the magneto-sensing surfaces of the third and fourth magnetoelectric transducers into magnetic field vectors in a vertical direction with respect to the magneto-sensing surfaces of the third and fourth magnetoelectric transducers, and also in opposite directions at each magneto-sensing surface, and the calculation unit includes a first calculation block that adds or subtracts output from the first to fourth magnetoelectric transducers, and outputs a calculation result.