Optical Gas Sensor with Joule-Heated Reflective Layer
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Solution Overview
Problem
Existing gas detectors for volatile compounds are complex, expensive, and require long operating times to determine chemical nature and concentration, often requiring additional analyses and consuming high energy.
Innovation Solution
An optical detection device with a sensitive reflective element that uses a transparent, porous sensitive layer and an electrically conductive layer for thermal desorption, allowing rapid detection and quantification of volatile compounds by varying light intensity, which correlates with desorption temperature and concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gas chromatography oven and concentrator are used for thermal desorption and concentration, then detection capability is improved, but device complexity and energy consumption increase
Solution Approach 1:
The patent extracts and eliminates the gas chromatography oven and concentrator from the detection system, retaining only the essential thermal desorption function integrated directly with the sensor. This removal of unnecessary components directly reduces device complexity while preserving the core detection capability through the sensitive layer's direct thermal desorption process.
Solution Approach 2:
The heating element in the patent serves multiple functions: it provides thermal desorption of volatile compounds from the sensitive layer, concentrates the desorbed compounds through localized heating, and enables detection. This multi-functionality eliminates the need for separate concentrator and oven devices, reducing overall system complexity while maintaining detection precision.
2Measurement precision
If additional analysis devices are used to determine pollutant presence, then measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The sensitive layer in the patent performs multiple functions: it selectively adsorbs specific volatile compounds based on chemical affinity, provides thermal desorption when heated, and enables optical detection through refractive index changes. This multi-functionality eliminates the need for separate analysis devices, reducing device complexity while maintaining the ability to accurately identify and measure pollutant presence.
Solution Approach 2:
The patent utilizes optical reflection measurements to detect changes in the sensitive layer's properties during volatile compound adsorption and desorption. The variation in reflected light intensity provides direct information about compound presence and concentration, eliminating the need for additional analysis devices while maintaining measurement accuracy.
3Temperature
If ITO layer and non-conductive element are used for heating and transduction, then heating function is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the heating function and optical transduction function into a single integrated sensitive layer structure. The sensitive layer itself serves as both the heating target and the optical detection element, eliminating the need for separate ITO heating layers and non-conductive separating elements. This integration significantly simplifies the manufacturing process and reduces component costs while maintaining effective heating and detection capabilities.
4Ease of operation
If resistance change measurement is used for desorption detection, then detection method is simplified, but chemical nature determination capability is lost
Solution Approach 1:
The patent uses optical reflection measurements to detect desorption events, providing simplified detection through light intensity variations. Simultaneously, the specific optical response characteristics and desorption temperature profiles obtained through this method enable determination of the chemical nature of desorbed compounds, thus avoiding information loss while maintaining operational simplicity.
Solution Approach 2:
The patent monitors changes in optical reflection parameters (intensity, wavelength) during thermal desorption to detect volatile compounds. By analyzing the specific parameter changes at different desorption temperatures, the system can both simplify detection and determine the chemical nature of compounds, resolving the contradiction between simplicity and information retention.
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 simple, rapid, and cost-effective detection and quantification of volatile compounds, even at low concentrations, with improved response times and reduced complexity compared to prior art.
Implementation Method 1
optical device (1) for detecting volatile compounds, characterised in that it comprises a sensitive reflective element (3), the reflected light intensity of which varies according to the volatile compounds contained in an atmosphere to be tested and their concentration
Implementation Method 2
illumination of the sensitive layer under an incident angle with the light source and measurement of the light intensity reflected by the sensitive reflective element
Implementation Method 3
an electrically conductive layer configured to heat the sensitive layer in order to allow desorption of the volatile compounds from the sensitive layer
Implementation Method 4
a sensitive reflective element whose reflected light intensity varies according to the volatile compounds contained in an atmosphere to be tested and their concentration
Data Source
Figure 1
Figure 2~3A
Figure 3B~4B
AI summary
The present invention relates to an optical device (1) for detecting volatile compounds, comprising: - a sensitive reflective element (3) comprising: * a substrate layer (31), * at least one sensitive layer (33) configured to allow the adsorption and desorption of the volatile compounds, and * an electrically-conductive layer (35) between the substrate layer (31) and the sensitive layer (33), configured to heat the sensitive layer (33) via the Joule effect, - a light source (5) arranged to illuminate the sensitive layer (33), - a light detector (7) configured for measuring the light intensity reflected by the sensitive reflective element (3), and - a processing and calculation unit (9). The present invention also relates to a method for detecting and quantifying volatile compounds using this optical detection device.