Stress Sensor Using Laminated Magnetic Layers for Multi-Directional Detection
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Solution Overview
Problem
Conventional stress sensors can only detect stress in a limited direction, requiring multiple sensors to detect stress in any in-plane direction, which is inefficient.
Innovation Solution
A stress sensor with a laminated stress detection layer comprising a first magnetic layer, a first non-magnetic layer, and a second magnetic layer, where the first and second magnetic layers have different magnetoelastic coupling constants, allowing stress detection by varying electrical resistance based on the relative angle of magnetization, enabling detection of stress in any in-plane direction with a single element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single resistor element is used for stress detection, then the device complexity is reduced, but the measurement precision is insufficient because it can only detect stress in a limited direction
Solution Approach 1:
The invention transitions from detecting only longitudinal stress to detecting stress in any in-plane direction by utilizing the planar geometry of the laminated magnetic layer structure. The stress detection layer is configured with specific in-plane directions that enable detection of stress components along multiple axes simultaneously, effectively adding dimensional capability to a single sensor element.
Solution Approach 2:
The stress detection layer employs a composite laminated structure consisting of multiple magnetic layers with different magnetoelastic coupling constants separated by nonmagnetic layers. This composite structure enables the sensor to detect stress in any in-plane direction by combining the responses of layers with different magnetic anisotropy properties, achieving multi-directional detection capability within a single element.
2Measurement precision
If multiple sensor elements are used to detect stress in any in-plane direction, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The invention merges the functionality of multiple stress sensors into a single laminated magnetic layer structure. By combining multiple magnetic layers with different magnetoelastic coupling constants and orientations within one stress detection layer, the device achieves multi-directional stress detection capability that would otherwise require multiple separate sensor elements, thereby reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The laminated stress detection layer is designed to perform multiple detection functions simultaneously. A single stress detection layer can detect stress components in different in-plane directions by utilizing the different magnetoelastic coupling constants of its constituent magnetic layers, making the sensor universal for multi-directional stress measurement without requiring additional specialized elements.
3Manufacturing precision
If conventional resistor-based stress sensors are used, then the manufacturing precision is easier to achieve, but the sensitivity is insufficient for accurate stress detection
Solution Approach 1:
The invention replaces the conventional electrical resistance-based detection mechanism with a magnetoresistive detection mechanism. Instead of relying solely on mechanical deformation of a resistor, the stress detection utilizes changes in electrical resistance caused by magnetization rotation in magnetic layers under stress, providing enhanced sensitivity while maintaining manufacturability through sputtering deposition 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
Enables accurate detection of stress in any in-plane direction using a single sensor element, enhancing sensitivity and reducing the need for multiple sensors, through the giant magnetoresistance effect.
Implementation Method 1
the first magnetic layer and the second magnetic layer have mutually different magnetoelastic coupling constants, such that a stress is detected by an electrical resistance dependent on a relative angle of magnetization between the first magnetic layer and the second magnetic layer varying depending on the stress that is externally applied
Implementation Method 2
enabling detection of stress in any in-plane direction with a single element through the giant magnetoresistance effect
Data Source
AI summary
A stress sensor includes a stress detection layer including a laminated body including a first magnetic layer, a first non-magnetic layer, and a second magnetic layer that are laminated, wherein the first magnetic layer and the second magnetic layer have mutually different magnetoelastic coupling constants, such that a stress is detected by an electrical resistance dependent on a relative angle of magnetization between the first magnetic layer and the second magnetic layer varying depending on the stress externally applied.