Magnetic Sensor Free Layer Shape Optimization
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Solution Overview
Problem
Conventional magnetic sensors with magnetoresistive effect elements struggle to achieve improved response characteristics, such as higher sensitivity and lower noise, due to the difficulty in optimizing the materials and film thickness of the free layers for different response requirements.
Innovation Solution
A magnetic sensor design featuring two types of magnetoresistive effect elements with distinct free layer shapes, where the first element has a shape that increases the slope of output exponentially and the second element has a shape that decreases the slope linearly, allowing for improved response characteristics tailored to each type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If materials and film thickness of the free layer are optimized, then response characteristics such as sensitivity are improved, but it becomes very difficult to further improve response characteristics for different response requirements
Solution Approach 1:
The patent applies local quality by giving different shapes to the free layers of different magnetoresistive effect elements. The first free layer has a first shape while the second free layer has a second shape different from the first. This allows each element to have locally optimized properties tailored to its specific response characteristic requirements, rather than using a uniform design for all elements.
Solution Approach 2:
The patent changes the shape parameter of the free layer to achieve different response characteristics. By varying the geometric shape of the free layer between different magnetoresistive effect elements, the patent creates exponential response characteristics in one element and linear response characteristics in another, thereby improving measurement precision without increasing device complexity.
2Ease of manufacture
If the same free layer shape is used for both magnetoresistive effect elements, then manufacturing is simplified, but different response characteristics (exponential and linear) cannot be achieved
Solution Approach 1:
The patent implements local quality by assigning different shapes to the free layers of different magnetoresistive effect elements. The first magnetoresistive effect element has a free layer with a first shape, while the second element has a free layer with a second shape. This enables each element to exhibit different response characteristics (exponential vs. linear) while maintaining a relatively simple multilayer structure that can be manufactured using standard processes.
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 design effectively enhances the sensitivity and accuracy of position detection for both absolute and incremental magnetic signals, achieving exponential and linear output changes respectively, thereby improving detection precision.
Implementation Method 1
a magnetoresistive effect element (MR element) where resistance is changed in association with a magnetization direction of the free layer according to an external magnetic field
Data Source
AI summary
A magnetic sensor is provided with first and second magnetoresistive effect elements that can detect an external magnetic field. The first and second magnetoresistive effect elements are a plurality of layers of multilayer body including free layers where their magnetization directions vary due to the external magnetic field. Shapes of the first and second magnetoresistive effect elements viewed from the upper side in the lamination direction are different from each other. The first magnetoresistive effect element has a shape that can increase a slope of an output of the first magnetoresistive effect element relative to the change of the external magnetic field. The second magnetoresistive effect element has a shape that can decrease a slope of an output of the second magnetoresistive effect element relative to the change of the external magnetic field compared to the slope of the output of the first magnetoresistive effect element.