Coil Actuated Pressure Sensor Magnetic Field Isolation
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Solution Overview
Problem
Current pressure sensing technologies using magnetic fields face challenges in accurately detecting pressure differentials due to interference from directly coupled magnetic fields and stray signals, which affect the sensitivity and accuracy of pressure measurements.
Innovation Solution
A pressure sensor design incorporating a chamber with a conductive and deformable portion, utilizing multiple magnetic field sensing elements to detect differences in distance between the conductive portion and the sensing elements, generating a reflected magnetic field to produce an output signal indicative of pressure differential, and employing materials like stainless steel, copper beryllium, and sapphire for the deformable membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic field sensing elements are used to detect pressure differentials, then pressure measurement capability is provided, but directly coupled magnetic fields and stray signals interfere with measurement accuracy
Solution Approach 1:
The pressure sensor divides the sensing system into separate functional components: a deformable membrane structure that experiences pressure differentials, and magnetic field sensing elements positioned to detect only reflected magnetic fields. The membrane is segmented into a conductive portion and a deformable portion, allowing differential movement that modulates the reflected magnetic field while isolating the sensing elements from direct magnetic field interference.
Solution Approach 2:
The conductive deformable portion of the membrane acts as an intermediary between the pressure differential and the magnetic field sensing elements. It converts mechanical deformation into reflected magnetic field variations that the sensing elements can detect, while the sensing elements remain positioned to avoid direct coupling with the magnetic field source, thus eliminating stray signal interference.
2Measurement precision
If multiple magnetic field sensing elements are used to detect distance differences, then measurement sensitivity is improved, but device complexity increases
Solution Approach 1:
The sensing system uses multiple magnetic field sensing elements positioned at different locations to detect differential distance changes of the membrane. Each sensing element measures the reflected magnetic field from a specific region of the deformable membrane, and by comparing these measurements, the system achieves enhanced pressure sensitivity without requiring complex individual sensor structures.
Solution Approach 2:
Multiple magnetic field sensing elements perform the same basic function of detecting reflected magnetic fields, but their different positions allow them to collectively measure differential membrane displacement. This multi-functional arrangement enables the system to extract multiple measurement parameters from identical sensing technology, improving sensitivity while maintaining structural simplicity.
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 design enhances the accuracy and sensitivity of pressure measurements by isolating the reflected magnetic field from directly coupled fields, providing a robust and precise method for detecting pressure changes.
Implementation Method 1
means for generating a reflected magnetic field from the chamber; means for generating a magnetic field signal in response to the reflected magnetic field
Implementation Method 2
at least one magnetic field sensing element disposed proximate to the coil and configured to detect a reflected field produced by the coil
Implementation Method 3
a chamber comprising a conductive portion and a deformable portion coupled to the conductive portion and susceptible to deformation in response to a pressure differential
Data Source
Figure 1
Figure 2
Figure 2A
AI summary
A pressure sensor includes a chamber comprising a conductive portion and a deformable portion coupled to the conductive portion and susceptible to deformation in response to a pressure differential between an interior of the chamber and an exterior of the chamber; at least one coil responsive to an AC coil drive signal; at least one magnetic field sensing element disposed proximate to the at least one coil and to the conductive portion of the chamber and configured to generate a magnetic field signal in response to a reflected magnetic field generated by the at least one coil and reflected by the conductive portion; and a circuit coupled to the at least one magnetic field sensing element to generate an output signal of the pressure sensor indicative of the pressure differential between the interior of the chamber and the exterior of the chamber in response to the magnetic field signal.