ESPI Fiber-Optic Interferometer for EM Field Displacement Measurement
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Solution Overview
Problem
Current measurement technologies cannot safely and accurately assess the mechanical properties of materials within strong electromagnetic fields due to interference and perturbation issues, limiting their use in hazardous environments like anechoic chambers.
Innovation Solution
A fiber-optic-based Electronic Speckle Pattern Interferometer (ESPI) system that uses a single-mode fiber to split coherent radiation into test and reference arms, allowing for remote, non-invasive, and non-perturbing measurements of displacement and thermomechanics by combining the beams with a large-beam collimator and multimode fiber, enabling long-range assessment without disrupting the EM fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EM interference shielding (Faraday cages) is used to protect electrical equipment, then equipment safety is improved, but the EM field is perturbed and measurement accuracy deteriorates
Solution Approach 1:
The patent replaces electrical/electronic measurement systems with an all-optical measurement system. The ESPI system uses laser beams, optical fibers, and cameras to measure material deformation, eliminating the need for electrical equipment that would require EM shielding. This substitution resolves the contradiction by removing the source of EM interference while maintaining measurement capability.
Solution Approach 2:
The patent introduces optical fibers as intermediaries to transmit measurement data from the hazardous EM field environment to safe measurement equipment located outside the anechoic chamber. The optical fibers act as isolators that carry information without conducting electromagnetic interference, allowing accurate measurement while protecting equipment.
2Measurement precision
If measurement equipment is placed in close proximity to the test material, then measurement capability is improved, but the equipment cannot withstand strong EM fields and safety deteriorates
Solution Approach 1:
Optical fibers serve as intermediaries that enable the measurement system to be positioned close to the test material while keeping the actual measurement equipment (cameras, processors) at a safe distance outside the EM field. The optical fibers transmit light and measurement data through the hazardous environment without being affected by strong EM fields.
Solution Approach 2:
The patent replaces electrical measurement sensors with optical sensors that are inherently immune to EM field interference. The laser-based ESPI system can operate in close proximity to the test material under EM field exposure without suffering from the electrical breakdown and arcing problems that plague conventional electrical equipment.
3Ease of operation
If conventional electrical measurement equipment is used, then ease of operation is improved, but the equipment suffers from electrical breakdown and arcing in strong EM fields
Solution Approach 1:
The patent replaces electrical measurement equipment with an all-optical ESPI system that uses laser illumination, optical beam splitting, and optical detection. This substitution eliminates electrical components that are vulnerable to breakdown and arcing in strong EM fields, while maintaining ease of operation through automated optical measurement and digital image processing.
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
Enables high spatial and temporal resolution measurements of material displacement and thermomechanics from a safe distance, providing real-time, non-destructive, and non-perturbing data on materials exposed to strong RF electromagnetic fields, overcoming previous limitations of proximity and interference.
Implementation Method 1
The laser produces coherent radiation that is coupled into a first portion of the single-mode fiber
Implementation Method 2
coupled into a first portion of the single-mode fiber by the first fiber optic coupler
Implementation Method 3
The first fiber beam splitter separates the coherent beam into a test arm directed by a second portion of the single mode fiber to the second output collimator and a reference arm
Implementation Method 4
a first output collimator, a splitter/combiner cube, and a camera... a second output collimator aimed at a first angle from a perpendicular axis to a test surface
Implementation Method 5
Electronic speckle pattern interferometer (ESPI) for long-range measurement of displacement of materials... measuring displacement of the test surface based on an electronic speckle pattern interferometer (ESPI) detected by the camera
Data Source
AI summary
A digital speckle pattern interferometer (DSPI) is provided for long-range measurement of displacement of materials within a hazardous environments. A test arm of a portion of coherent beam from a laser is aimed at a selected angle to traverse a distance to a test surface. An input collimator has a lens wide enough to receive a reflected beam from the test surface and is focused at a corresponding distance. The reflected beam is combined with a reference beam split from the coherent radiation onto a camera for measuring displacement of the test surface based on an electronic speckle pattern interferometer (ESPI).