Miniaturized Optical Sensor for Trace Gas Detection

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Solution Overview

Problem

Current gas leak detection systems, especially those using hand-held laser sighted guns and gas-draw sensors on drones, face challenges such as high costs, manual inspection overhead, and accuracy issues due to downdraft dispersion, making them unsuitable for large-scale applications like refinery monitoring.

Innovation Solution

A miniaturized high-sensitivity optical instrument using integrated photonics and wafer-scale fabrication for remote detection of trace gases, mounted on UAVs, which employs interferometers and Fourier-transform spectrometry to generate spectrum information for accurate gas species identification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If hand-held laser sighted guns and gas-draw sensors are used for gas leak detection, then portability is improved, but measurement precision deteriorates due to downdraft dispersion

Engineering Contradiction:
ImproveportabilityVSAvoidmeasurement precision
Core Design Contradiction:
Length of moving objectVSMeasurement precision

Solution Approach 1:

The patent replaces mechanical gas-draw sensors with an optical detection system using laser beams and interferometers. The system uses optical fields instead of mechanical sampling to detect trace gases, eliminating the downdraft dispersion problem while maintaining portability through miniaturized integrated photonic components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an optical intermediary (laser beam) to transfer energy through the gas plume without physical contact. The laser beam acts as a mediator that interacts with gas molecules via Raman scattering and absorption, allowing remote detection without being affected by aerodynamic downdraft.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If high-sensitivity optical cavity systems are used for trace gas detection, then measurement precision is improved, but manufacturing cost and device complexity increase

Engineering Contradiction:
Improvemeasurement precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent extracts the essential detection function from complex optical cavity systems and implements it using simpler integrated photonic components. By taking out only the necessary interferometric measurement capability and implementing it through compact waveguide-based interferometers, the system achieves comparable precision with much lower manufacturing cost and complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses integrated photonic copies of traditional optical components. Instead of building large optical cavities, the system uses miniaturized waveguide interferometers that replicate the essential interference measurement function in a compact, manufacturable form factor using standard semiconductor fabrication processes.

Inventive Principle:
Principle #26Copying

3Measurement precision

If multiple interferometers are used for spectrum analysis, then gas species identification accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvegas species identification accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple interferometer functions into a single integrated photonic chip. Multiple interferometers are fabricated simultaneously on the same chip using waveguide structures, sharing common input/output channels and processing electronics, thereby reducing overall device complexity while maintaining the spectral resolution benefits of multiple interferometers.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated photonic chip serves multiple functions: it acts as a beam splitter, waveguide array, and interferometer bank simultaneously. The same physical structure performs spectral analysis for multiple gas species detection, eliminating the need for separate dedicated components for each function and reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution enables accurate, cost-effective, and scalable gas leak detection at standoff distances, improving measurement precision and reducing manufacturing costs compared to traditional high-sensitivity optical cavity systems, while avoiding downdraft interference.

Implementation Method 1

applying, by the processing circuitry, a forward Fourier-transform on the digitized signal to generate spectrum information for the plurality of interferometers, and determining, by the processing circuitry, a gas species has been detected using one or more intensity of absorption features of the spectrum information

Methodology Applied
Scientific EffectAbsorption spectroscopy: Absorption Spectroscopy

Data Source

PatentEP3690418B1Optical sensor for trace-gas measurement
Publication Date: 2021.07.28 HONEYWELL INTERNATIONAL INC
  • EP3690418B1 patent drawingFigure 1
  • EP3690418B1 patent drawingFigure 2
  • EP3690418B1 patent drawingFigure 3

AI summary

A system for detecting trace-gas includes an optical sensor mounted on a vehicle and processing circuitry. The optical sensor includes a plurality of interferometers configured to collect samples. The processing circuitry is configured to generate a digitized signal based on the samples, apply a forward Fourier-transform on the digitized signal to generate spectrum information for the plurality of interferometers, and determine a gas species has been detected using one or more intensity of absorption features of the spectrum information corresponding to the gas species from the spectrum information.