Laser-Based Gas Analysis Apparatus for High Accuracy
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Solution Overview
Problem
Existing solid sample analyzing apparatuses face challenges in maintaining high analysis accuracy, especially in low concentration ranges, due to poor signal-to-noise ratios caused by wavelength selective filters, and require frequent maintenance of ultraviolet light sources.
Innovation Solution
The apparatus employs a laser light source that irradiates the gas with a modulated laser light tailored to the component being measured, eliminating the need for wavelength selective filters and using wavelength modulation spectroscopy to calculate component concentrations, thereby reducing maintenance frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a wavelength selective filter is provided in front of the photodetector to measure component concentration, then the measurement specificity is improved, but the light intensity is reduced resulting in poor signal-to-noise ratio
Solution Approach 1:
The patent removes the wavelength selective filter from the optical path and replaces it with a laser light source that inherently emits only at the specific absorption wavelength of the target component. This extraction of the filtering function and its replacement with a wavelength-specific light source eliminates the light intensity loss while maintaining measurement specificity.
Solution Approach 2:
The patent changes the light source parameter from broad-spectrum infrared light to monochromatic laser light at a specific wavelength matching the absorption peak of the target component. This parameter change in light wavelength enables direct resonance with the molecular absorption characteristics without requiring spectral filtering.
2Measurement precision
If an ultraviolet light source is used in the ultraviolet fluorescence method to achieve high sensitivity, then the analysis accuracy in low concentration range is improved, but the light source intensity decreases with age requiring frequent replacement
Solution Approach 1:
The patent replaces the expensive, short-lived ultraviolet light source with a more stable laser light source that has longer operational life. While the ultraviolet source provides high sensitivity, it requires frequent replacement; the laser source trades some sensitivity for significantly improved reliability and reduced maintenance frequency.
Solution Approach 2:
The patent substitutes the ultraviolet fluorescence excitation mechanism with a laser-based absorption detection mechanism. This substitution changes the fundamental detection principle from fluorescence to direct absorption, using a more stable light source while achieving comparable or superior measurement performance.
3Illumination intensity
If a laser light source with oscillation wavelength tailored to the component is used, then the signal-to-noise ratio is increased by eliminating the wavelength selective filter, but the device complexity increases
Solution Approach 1:
The patent makes the laser light source perform multiple functions: it provides the illumination source, acts as the wavelength selector, and serves as the reference for absorption measurement. This consolidation of functions into a single component simplifies the overall device structure despite the sophistication of the laser technology itself.
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 enhances signal-to-noise ratios, improves analysis accuracy across all concentration ranges, and reduces maintenance needs, particularly by eliminating the requirement for frequent ultraviolet light source replacements.
Implementation Method 1
a gas analysis section which comprises a laser light source that irradiates the gas with laser light, and a photodetector which detects an intensity of the sample light as being the laser light that has transmitted through the gas
Implementation Method 2
The laser light source emits a modulated light whose wavelength is modulated at a predetermined modulation frequency
Data Source
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AI summary
The present claimed invention is a sample analyzing apparatus that analyzes a component to be measured securely while reducing a frequency of maintenance of the sample analyzing apparatus. The sample analyzing apparatus comprises a heating furnace 2 that heats a sample (W) held by a sample holding body and a gas analysis section 3 that analyzes a component to be measured contained in a gas generated by heating the sample (W), and the gas analysis section 3 comprises a laser light source 12 that irradiates the gas with a laser light, and a photodetector 13 that detects an intensity of a sample light as being the laser light that has transmitted through the gas.