Magnetic Sensor Device Detecting Hard Magnetic Materials
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Solution Overview
Problem
Conventional magnetic sensor devices face difficulties in accurately detecting hard magnetic materials due to saturation of magnetic output when both soft and hard magnetic materials are present, and existing devices lack clear differentiation between the two.
Innovation Solution
The magnetic sensor device employs a magnetoresistance effect element that utilizes a leakage magnetic field from a yoke to detect hard magnetic materials, avoiding saturation and enabling precise differentiation by using the leakage magnetic field as the bias magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a strong bias magnetic field is applied to detect both soft and hard magnetic materials, then the magnetic output is strong, but the magnetoresistance effect element becomes saturated and cannot differentiate between soft and hard magnetic materials
Solution Approach 1:
The patent applies different magnetic field strengths to different detection purposes: a strong bias magnetic field is applied to the first magnetoresistance effect element for detecting soft magnetic materials, while a weak bias magnetic field is applied to the second magnetoresistance effect element for detecting hard magnetic materials. This local differentiation of magnetic field quality enables both detection types to operate in their optimal ranges without mutual interference or saturation.
Solution Approach 2:
The patent divides the single detection function into two separate detection paths using two magnetoresistance effect elements. Each element is independently configured with its own bias magnetic field strength and detection threshold, allowing the system to segment the detection task into soft magnetic material detection and hard magnetic material detection, thereby resolving the saturation problem.
2Measurement precision
If a weak bias magnetic field is applied to avoid saturation, then the magnetoresistance effect element can differentiate magnetic materials, but the magnetic output becomes too weak for reliable detection
Solution Approach 1:
The patent segments the detection function into two parallel channels: one channel uses a weak bias magnetic field optimized for hard magnetic material detection with high precision, while the other channel uses a strong bias magnetic field optimized for soft magnetic material detection. This segmentation allows each channel to operate at its optimal sensitivity without compromising overall detection capability.
Solution Approach 2:
The magnetic sensor device achieves multi-functionality by incorporating two magnetoresistance effect elements that can simultaneously detect both soft and hard magnetic materials. Each element is universally capable of detection but is optimized for a specific material type through differentiated bias magnetic field application, enabling the system to handle diverse detection requirements.
3Device complexity
If a single magnetoresistance effect element is used to detect both soft and hard magnetic materials, then the device structure is simple, but it cannot achieve high accuracy in hard magnetic material detection due to saturation
Solution Approach 1:
The patent segments the single detection element into two specialized elements: the first magnetoresistance effect element is dedicated to soft magnetic material detection with strong bias field, and the second magnetoresistance effect element is dedicated to hard magnetic material detection with weak bias field. This segmentation resolves the saturation issue while maintaining relatively simple device architecture.
Solution Approach 2:
Instead of using a single element with compromised performance, the patent inverts the approach by using two elements with specialized optimization. Rather than trying to make one element work for both purposes, the solution reverses to dedicated specialization, where each element excels at its specific detection task.
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 configuration allows for high-accuracy detection of hard magnetic materials while minimizing sensitivity to soft magnetic materials, effectively distinguishing between the two.
Implementation Method 1
a magnetoresistance effect element to which is applied a leakage magnetic field released to the exterior of a yoke from the yoke
Implementation Method 2
uses a leakage magnetic field released to the outside of a yoke
Data Source
AI summary
A magnetic sensor device includes: a magnet; yokes arranged on the magnet; and a magnetoresistance effect element to which is applied a leakage magnetic field emitted from the yokes to an exterior thereof. A detection region of the magnetoresistance effect element is at the side opposite to the magnet. The magnetoresistance effect element detects a change of a bias magnetic field of the magnetoresistance effect element that occurs when the object to be detected including the hard magnetic material passes through the detection region. The magnetic sensor device can accurately detect an object to be detected using a hard magnetic material.