Fibre-Optic Sensor Structure for Passive Thermal Strain Compensation
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Solution Overview
Problem
Traditional fibre-optic sensors are susceptible to temperature-induced measurement errors due to thermal expansion, requiring complex calibration and post-processing to compensate for temperature changes, which can lead to inaccuracies outside the calibrated temperature range.
Innovation Solution
The sensor employs structural members made from materials with different coefficients of thermal expansion to minimize temperature-induced strain in the optical fibre, using a passive compensation method that maintains a constant suspended length, thereby reducing the need for active calibration and post-processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature compensation is performed by integrating a temperature sensor and extensive calibration, then measurement accuracy is improved, but device complexity and calibration effort increase significantly
Solution Approach 1:
The patent changes the material parameters (coefficients of thermal expansion) of the structural members to achieve temperature compensation. By selecting materials with different thermal expansion coefficients for the first and second structural members, the system passively compensates for temperature-induced measurement errors without requiring additional sensors or complex calibration procedures.
Solution Approach 2:
The patent converts the harmful effect of thermal expansion into a beneficial compensation mechanism. The different thermal expansion coefficients of the structural members create opposing effects that cancel each other out, transforming temperature-induced errors into a self-correcting system that maintains measurement accuracy across temperature variations.
2Adaptability or versatility
If the sensor operates over a broad temperature range, then adaptability is improved, but measurement accuracy deteriorates due to temperature-induced errors
Solution Approach 1:
The patent achieves broad temperature range adaptability while maintaining accuracy by changing the material parameters of the structural members. The different coefficients of thermal expansion allow the system to operate across wide temperature ranges without suffering from temperature-induced measurement errors, as the thermal effects are passively compensated through material selection.
Solution Approach 2:
The patent directly applies the principle of thermal expansion by selecting materials with different coefficients of thermal expansion for the structural members. This causes the members to expand or contract by different amounts in response to temperature changes, creating a compensating effect that maintains measurement accuracy across broad temperature ranges without requiring active temperature control or calibration.
3Measurement precision
If complex post-processing is performed to compensate for non-linear temperature effects, then measurement accuracy is improved, but loss of time and processing complexity increase
Solution Approach 1:
The patent performs the compensation action preliminarily through material selection rather than through post-processing. By choosing structural members with different thermal expansion coefficients, the system is pre-configured to automatically compensate for temperature effects during operation, eliminating the need for time-consuming non-linear post-processing and calibration procedures.
Solution Approach 2:
The patent implements self-service temperature compensation where the sensor structure automatically compensates for its own temperature-induced errors. The different thermal expansion coefficients of the structural members create a self-correcting mechanism that eliminates measurement errors without requiring external calibration or complex post-processing, saving time and computational resources.
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 provides a more robust fibre-optic sensor with reduced temperature sensitivity, ensuring accurate measurements over a broad temperature range without the need for complex calibration or post-processing.
Implementation Method 1
the one of the first and second structural members is arranged to move in dependence of the physical quantity that is measured; and wherein said first structural member is made from a first material having a first coefficient of thermal expansion and said second structural member is made from a second material having a second coefficient of thermal expansion that is different from said first coefficient of thermal expansion
Data Source
AI summary
A fibre-optic sensor for measuring a physical quantity, such as a pressure, force, acceleration or tilt, includes an optical fibre having a measurement section for measuring a strain in the fibre, and first and second structural members. The optical fibre is connected to a first fibre connection section of the first structural member and to a second fibre connection section of the second structural member. The first and second connection sections are arranged on opposite sides of the measurement section, such that at least the measurement section is suspended between the first and second fibre connection sections. At least one of the structural members is movable relative to the other in dependence of the physical quantity that is measured. The structural members are made from materials having different coefficients of thermal expansion such that a temperature induced strain in said optical fibre due to a temperature change is reduced.