Optical Magnetic Sensor Using Magnetostrictive Material
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Solution Overview
Problem
Current magnetic sensors face challenges in accurately measuring low-strength magnetic fields and distinguishing between ferromagnetic objects while being sensitive to environmental factors like temperature and acoustic disturbances.
Innovation Solution
The integration of magnetically sensitive materials, such as Terfenol-D, into optical resonators and interferometers that change dimension in response to magnetic fields, combined with advanced signal processing techniques like differential operation and tomographic processing, to enhance sensitivity and reduce environmental interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic sensors are used, then they can detect magnetic fields, but they cannot accurately measure low-strength magnetic fields and are sensitive to environmental factors
Solution Approach 1:
The patent introduces an optical intermediary system that converts magnetic field changes into optical signal changes. The magnetic field induces dimensional changes in the test object, which are then detected optically through resonant frequency shifts or interference pattern changes, providing high precision while being immune to environmental factors like temperature and acoustic disturbances that affect conventional sensors
Solution Approach 2:
The patent replaces conventional mechanical/electrical magnetic sensors with an optical measurement system. Instead of using coils or Hall effect sensors that are mechanically and environmentally sensitive, the system uses optical resonators and interferometers that detect magnetic field-induced dimensional changes through light wave interactions, achieving superior precision and environmental immunity
2Measurement precision
If ferromagnetic objects are detected, then magnetic fields can be measured, but it becomes difficult to distinguish between target objects and clutter
Solution Approach 1:
The patent applies local quality by measuring the specific resonant frequency characteristics and dimensional change patterns of different ferromagnetic objects. Each object has unique magnetic properties that produce distinct optical response signatures, allowing the system to discriminate between target objects and clutter based on their individual frequency and amplitude characteristics
Solution Approach 2:
The patent utilizes parameter changes by monitoring variations in resonant frequency and dimensional response as objects are subjected to varying magnetic field strengths. The system measures how different objects respond at different frequencies and amplitudes, creating a signature profile that enables accurate discrimination and identification of target objects from background clutter
3Measurement precision
If magnetic sensors are made more sensitive, then low-strength fields can be detected, but environmental interference increases
Solution Approach 1:
The optical system acts as an intermediary that decouples the magnetic field detection from environmental influences. The optical resonators and interferometers are inherently immune to temperature and acoustic disturbances, providing reliable high-sensitivity measurement even in harsh environmental conditions where conventional sensors would fail
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 approach enables the detection of magnetic fields as low as one femto-Tesla and effectively discriminates between target objects and clutter, providing high accuracy and robustness against environmental effects.
Implementation Method 1
incorporating into resonators or interferometers materials that change dimension in a changing magnetic field
Implementation Method 2
materials that change dimension in response to changes in magnetic field
Implementation Method 3
optical resonators... supports dimensional change sensitivity down to less than one part in 10^11 when operated at high signal-to-noise ratio
Data Source
AI summary
An optically sensitive device includes a material that changes dimension in response to a change in a magnetic field. In an embodiment, the optically sensitive device is configured to measure a change in a magnetic field as a function of the change of dimension of the material.