Scheimpflug LIDAR Gas Detection with LED Source
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Solution Overview
Problem
Existing atmospheric LIDAR systems face challenges in achieving high resolution and sensitivity for gas molecule profiling, mapping, and visualization, particularly in detecting the O2-hole with millimeter resolution and operating within milliseconds, due to limitations in transmitter and receiver spectrally narrow information retrieval, leading to high costs and bulkiness.
Innovation Solution
A method employing a multimode continuous wave laser diode to emit light covering multiple absorption lines, using a Scheimpflug configuration with a light sensor to achieve high spectral resolution, allowing simultaneous illumination of spectral bands and self-calibration, enabling the determination of gas concentration, temperature, and pressure from scattered light attenuation ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional pulsed neodymium-doped yttrium aluminium garnet lasers are used, then high peak power is achieved, but system weight and size increase significantly
Solution Approach 1:
The patent replaces heavy mechanical laser systems with a lightweight LED light source that achieves the required peak power through electronic modulation rather than mechanical complexity. The LED system uses a photodetector array to detect and process light signals, substituting the bulky mechanical laser components with a compact electronic detection system.
Solution Approach 2:
The patent creates a virtual copy of the laser functionality using an LED that can be electronically controlled to emit light at specific wavelengths. Instead of using a physical laser with complex tuning mechanisms, the system uses an LED whose emission characteristics can be replicated and controlled through electronic means, achieving the same functional outcome with significantly reduced weight.
2Measurement precision
If conventional LIDAR systems are used, then detection capability is achieved, but spatial and temporal resolution are poor
Solution Approach 1:
The patent segments the detection function across multiple photodetectors arranged in an array, each capable of detecting light at different wavelengths simultaneously. This segmentation allows the system to achieve high spectral resolution by distributing the detection task across multiple independent elements, enabling both high resolution and fast measurement capability.
Solution Approach 2:
The patent transitions from sequential measurement (time-domain) to simultaneous multi-wavelength detection (spectral domain). By using a photodetector array that can detect multiple wavelengths at once, the system achieves high temporal resolution while maintaining spectral precision, effectively adding a dimensional approach to the measurement process.
3Measurement precision
If Raman channels are expanded to improve aerosol detection, then specificity increases, but system complexity and measurement time increase
Solution Approach 1:
The patent uses a single LED light source with adjustable wavelength that can detect multiple gas types and aerosols by tuning to different absorption lines. This universal approach replaces the need for multiple specialized detection channels (including Raman channels), achieving high specificity for different target substances while maintaining system simplicity through a single multi-functional detection system.
Solution Approach 2:
The patent changes the detection parameter from fixed wavelength detection to tunable wavelength detection. By dynamically adjusting the LED wavelength to match specific gas absorption lines, the system achieves high specificity for different gases and aerosols without requiring multiple fixed detection channels, thereby reducing overall system complexity.
4Measurement precision
If DIAL method is used to achieve high specificity, then gas detection accuracy improves, but system cost and complexity increase
Solution Approach 1:
The patent replaces expensive, complex laser systems with a more economical LED light source that can be dynamically tuned to required wavelengths. The LED system achieves the necessary detection accuracy for DIAL measurements at a lower cost and with reduced complexity, using a simpler light source that can be electronically controlled rather than mechanically tuned.
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 enables precise determination of gas properties, such as O2 and H2O levels, with sub-second time resolution and millimeter spatial resolution, reducing system size and cost while improving operational efficiency and practical applications.
Implementation Method 1
emitting light, comprising a plurality of wavelengths covering a plurality of absorption lines of the gas, along a first axis, the light being scattered by particles of the gas resulting in a scattered light
Implementation Method 2
an optical arrangement having an optical plane and being configured to direct the scattered light on to a light sensor
Implementation Method 3
a light sensor having at least one pixel columns, wherein the pixel columns are aligned to an image plane and configured to output a sensor image
Implementation Method 4
wherein the first axis, the optical plane, and the image plane intersect such that a Scheimpflug condition is achieved
Implementation Method 5
emitting light, comprising a plurality of wavelengths covering a plurality of absorption lines of the gas
Data Source
AI summary
A method is provided for detecting a property of a gas comprising: emitting a light, comprising a plurality of wavelengths covering a plurality of absorption lines of the gas, along a first axis, the light being scattered by particles of the gas resulting in a scattered light, generating a sensor image using a detection arrangement configured to receive the scattered light and comprising: an optical arrangement having an optical plane and being configured to direct the scattered light on to a light sensor, the light sensor having at least one pixel columns, wherein the pixel columns are aligned to an image plane and configured to output a sensor image, wherein the first axis, the optical plane, and the image plane intersect such that a Scheimpflug condition is achieved, determining, from the sensor image, properties of the gas at a plurality of positions along the first axis.