Micro-barometer with Interferometric Transducer for Infrasonic Detection
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Solution Overview
Problem
Current bellows microbarometers have limited measurement spectral band, are sensitive to electromagnetic disturbances, and retain thermal sensitivity due to assembly constraints, limiting their effectiveness in measuring infrasonic waves.
Innovation Solution
The design incorporates an interferometric transducer with integrated optics technology, using a silica substrate with etched optical guides and separation zones to measure pressure variations, replacing traditional electromagnetic sensors and minimizing thermal influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic sensors (LVDT type) are used to measure bellows displacement, then the measurement function is achieved, but the device becomes sensitive to electromagnetic disturbances and has limited spectral band
Solution Approach 1:
The patent replaces the electromagnetic LVDT sensor with an optical interferometric transducer. The interferometric component uses optical beams and reflective elements to measure bellows displacement, substituting electromagnetic measurement principles with optical principles, thereby eliminating sensitivity to electromagnetic disturbances while maintaining measurement capability
Solution Approach 2:
The patent changes the measurement parameter domain from electromagnetic field measurements to optical field measurements. By using interferometric techniques with optical beams, the system transforms the measurement approach to operate in the optical domain, which is inherently immune to electromagnetic interference affecting traditional sensors
2Device complexity
If traditional electromagnetic sensors are used, then the device structure is established, but thermal sensitivity remains due to assembly constraints
Solution Approach 1:
The patent replaces the electromagnetic sensor assembly with an integrated optical interferometric component that can be directly mounted on the bellows cover. This substitution simplifies the mechanical assembly structure and reduces the number of thermal pathways, thereby reducing thermal sensitivity while maintaining the measurement function
3Measurement precision
If LVDT electromagnetic sensors are used, then displacement measurement is achieved, but the measurement spectral band is limited
Solution Approach 1:
The patent changes the measurement system's operational domain from electromagnetic to optical frequencies. The interferometric transducer uses optical beam interference to measure displacement, enabling the system to respond to a broader range of frequencies including higher spectral bands that were previously limited by electromagnetic sensor characteristics
Solution Approach 2:
The patent enhances the dynamic response capability of the measurement system. The optical interferometric component can track rapid bellows displacements across a wider frequency spectrum, improving the system's ability to measure infrasonic waves across different spectral bands with enhanced adaptability
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 enhances the spectral measurement band, reduces thermal sensitivity, and minimizes electromagnetic interference, enabling more precise detection of infrasonic waves with improved robustness for outdoor use.
Implementation Method 1
this component comprising guide lines optical, separation and optical combination zones within the same substrate, in integrated technology, this interferometric component being formed of a silica substrate, zones of which have been modified so as to form said optical lines, the separation and combination zones
Implementation Method 2
emit a fraction of a beam towards this element and capture this beam after reflection on this reflecting element
Implementation Method 3
Any variation in pressure deforms this bellows by generating a linear displacement of its upper part
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5J
AI summary
A microbarometer with a bellows comprises a reference base 11, a bellows 12 of which one edge is fixed to a reference surface of said base, having an elongation direction perpendicular to this reference surface, a cover 13 closing the other edge of this bellows so as to sealingly insulate it from the outside, the bellows being placed in conditions in which the variations in elongation of same are directly proportional to the pressure variations induced by infrasonic waves around it; it further comprises a reflective element 14 integral with this cover and an interferometric component 16 designed to be able to receive a beam from a source and integral with the reference surface of the base, having an input/output optical path facing the reflective element, parallel to the elongation direction of the bellows, so as to be able to emit a beam fraction towards this element and to sense this beam after reflection on this reflective element, this component comprising optical guide lines, and optical separation and combination areas within a same substrate, using integrated technology.