Fabry-Perot Sensor With Inclined Reflective Surface
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Solution Overview
Problem
Existing sensors for measuring large displacements are prone to interference from temperature and electromagnetic sources, limiting their precision and durability, especially in dynamic and extreme temperature conditions.
Innovation Solution
A Fabry-Perot sensor utilizing an optic fiber with a displacement converting device, where the optic fiber forms a Fabry-Perot cavity with a reflecting surface, allowing for precise measurement of displacement by varying the cavity length, which is resistant to temperature and electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If electric principle sensors are used to measure large displacement, then measurement range is improved, but susceptibility to temperature and electromagnetic interference worsens
Solution Approach 1:
The patent replaces electric principle sensors with an optical fiber-based Fabry-Perot sensor system. The measuring probe connects through a conversion body to a longitudinal sliding block with an inclined reflective surface, forming an optical cavity that measures displacement optically rather than electrically, thereby eliminating susceptibility to electromagnetic interference while maintaining large measurement range capability
Solution Approach 2:
The patent changes the measurement parameter from electrical signals to optical path length changes. By forming a Fabry-Perot cavity where the cavity length varies with displacement, the system measures large displacements through optical phase changes rather than electrical resistance or voltage changes, providing immunity to electromagnetic interference and temperature effects
2Reliability
If optic fiber sensor is used to eliminate electromagnetic interference, then anti-interference capability is improved, but measurement precision for large displacement worsens
Solution Approach 1:
The patent introduces an inclined reflective surface at an angle θ to the optical axis on the longitudinal sliding block. This converts linear displacement along the optical axis into angular reflection, creating an optical path length change that is magnified by the factor 1/cos(θ). This dimensional transformation allows precise measurement of large displacements while maintaining optical fiber immunity to electromagnetic interference
Solution Approach 2:
The patent modifies the optical cavity parameters by introducing the inclined reflective surface angle θ. The relationship between probe displacement and cavity length change becomes non-linear (y=ax where a>1), providing enhanced measurement sensitivity for large displacements while maintaining the optical fiber's inherent anti-interference properties
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
The sensor achieves high precision and durability, capable of measuring large displacements with minimal impact from temperature variations and electromagnetic interference, suitable for static and dynamic forces in extreme conditions.
Implementation Method 1
the optic fiber end surface disposed at the bottom end of the optic fiber and the reflecting surface arranged on the upside of reflecting surface, thus a Fabry-Perot cavity is formed between the end surface of optic fiber and the reflecting surface on the upside of the longitudinal sliding block
Implementation Method 2
A reflecting surface is disposed at the upside of the longitudinal sliding block, wherein the reflecting surface has an inclined angle of θ with the central axis of the present sensor; the conversion body converts the lateral slide of the measuring probe to the longitudinal slide of the longitudinal sliding block
Data Source
AI summary
The present invention provides the Fabry-Perot (F-P) sensor compromising housing, measuring probe, longitudinal sling block, and displacement converting device. The optic fiber passes through upside sealing ring and extends into upside through hole with the optic fiber end surface disposed at the bottom; the upside of longitudinal sliding block is disposed with reflecting surface, thus a Fabry-Perot cavity is formed between part of the fiber end surface at the bottom of the fiber and the reflecting surface on the upside of longitudinal sliding block. The displacement converting device will convert the lateral slides of the measuring probe into the slides of the longitudinal sliding block, which thus changes the distance from the reflecting surface to the fiber end surface and changes the Fabry-Perot cavity length. Further, the sliding distance of the measuring probe can be calculated after the variation of the Fabry-Perot cavity length measured in according with the Fabry-Perot principle.