Gas Sensor Buffer Layer for Thermal Stability
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Solution Overview
Problem
Micro gas sensors fail due to long-term high working temperatures, which affect their sensitivity and mechanical strength, leading to potential breakage and reduced accuracy in gas detection, especially when detecting specific gases like carbon monoxide in environments with interfering substances like alcohol.
Innovation Solution
A gas sensor design incorporating a substrate, insulating film, heating unit, electrode pair, buffer layer, and gas sensing layer with a nano-catalyst, where the buffer layer enhances mechanical strength and thermal stability, reducing the impact of high temperatures and improving sensitivity by acting as a conductive intermediary between the electrode pair and gas sensing layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gas sensor operates at high temperature to achieve good sensitivity, then the sensing sensitivity is improved, but the mechanical strength deteriorates leading to potential breakage
Solution Approach 1:
The patent employs a composite structure consisting of a ceramic substrate, metal heating electrode, insulating film, and buffer layer. This composite material approach allows the sensor to operate at high temperatures for good sensitivity while the ceramic substrate and buffer layer provide the necessary mechanical strength and thermal stability to prevent breakage.
2Duration of action of moving object
If the gas sensor operates at high temperature for long-term use, then the detection function is maintained, but the reliability deteriorates due to component failure
Solution Approach 1:
The buffer layer is specifically designed to withstand thermal stress and protect the electrode pair from damage during long-term high-temperature operation. This preventive measure ensures that the electrode pair maintains good electrical contact with the ceramic substrate throughout the sensor's operational life, preventing premature failure and maintaining reliability.
Solution Approach 2:
The sensor is divided into distinct functional layers (ceramic substrate, heating electrode, insulating film, buffer layer, gas sensing layer), where each layer is optimized for its specific function. This segmentation allows the electrode pair to be protected from thermal stress while maintaining heating functionality, enabling long-term reliable operation.
3Device complexity
If a conventional structure without buffer layer is used, then the device complexity is reduced, but the sensing sensitivity deteriorates
Solution Approach 1:
The buffer layer acts as an intermediary between the electrode pair and the gas sensing layer. It provides a stable platform that ensures good electrical contact while allowing the gas sensing layer to maintain high sensitivity. The buffer layer's specific resistance and thermal expansion properties are optimized to enhance overall sensor performance without adding excessive complexity.
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
The buffer layer significantly improves the mechanical strength and sensitivity of the gas sensor, allowing for accurate detection of target gases like carbon monoxide while minimizing interference from other gases, such as alcohol, and enabling a more reliable and practical measurement circuit for electronic products.
Implementation Method 1
The heating unit is embedded in the insulating film and located above the opening
Implementation Method 2
The buffer layer is electrically connected to the electrode pair, and at least part of an orthogonal projection of the buffer layer on the first surface is located on the substrate next to the opening
Implementation Method 3
The gas sensing layer is disposed on the buffer layer, and the gas sensing layer is provided with a nano-catalyst therein
Data Source
AI summary
A gas sensor is provided. The substrate of the gas sensor has a first surface, a second surface and a cavity. The cavity has an opening at the first surface. An insulating film is disposed on the first surface and covers the opening. A heating unit is embedded in the insulating film and located above the opening. An electrode pair is disposed on the insulating film and electrically separated from the heating unit. A buffer layer is disposed on the insulating film and located above the heating unit. The buffer layer is electrically connected to the electrode pair, and at least part of an orthogonal projection of the buffer layer on the first surface is located on the substrate next to the opening. The gas sensing layer is disposed on the buffer layer and has a nano-catalyst therein.