Gas Sensor Noise Suppression via Shielded Film Structure
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Solution Overview
Problem
Existing gas sensors face challenges in accurately detecting gas concentrations due to noise in the electrical resistance signals, which is exacerbated by high currents used for heating, leading to reduced sensitivity and accuracy.
Innovation Solution
Incorporating a conductive member with fixed potential between the resistance layer and conductive layer in the sensor design, which acts as a shield to suppress noise, while maintaining a higher current flow through the conductive layer for effective heating and a lower current through the resistance layer for precise detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high current is used for heating the conductive layer, then heating effectiveness is improved, but noise in the electrical resistance signal increases
Solution Approach 1:
The sensor structure is segmented into distinct functional layers: a conductive layer for heating and a resistance layer for detection, positioned at different locations. This spatial segmentation allows independent optimization of heating efficiency and detection accuracy, enabling high current for heating without directly affecting the detection region.
Solution Approach 2:
A gap is introduced as an intermediary space between the conductive layer and the resistance layer. This gap acts as a thermal mediator that allows heat to reach the detection region while electrically isolating the high-current heating path from the low-current detection path, thereby suppressing noise in the resistance signal.
2Measurement precision
If current through the resistance layer is reduced for precise detection, then measurement precision is improved, but heating effectiveness deteriorates
Solution Approach 1:
The sensor divides the current path into two separate routes: one through the conductive layer for heating and another through the resistance layer for detection. This segmentation enables the heating current to flow independently at high amplitude without passing through the sensitive resistance layer, maintaining both heating effectiveness and detection accuracy.
Solution Approach 2:
The gap between the conductive layer and resistance layer serves as an intermediary that thermally couples the two layers while electrically decoupling them. This allows the resistance layer to be heated effectively by the conductive layer without requiring high current to flow directly through it, thus preserving measurement precision.
3Measurement precision
If conductive member with fixed potential is added between resistance layer and conductive layer, then noise suppression is improved, but device complexity increases
Solution Approach 1:
A conductive member with fixed potential is introduced as an intermediary element between the conductive layer and the resistance layer. This intermediate structure provides a stable electrical reference that shields the resistance layer from electrical noise and potential fluctuations, improving signal quality without requiring complex active noise cancellation circuits.
Solution Approach 2:
The conductive member is maintained at a fixed potential, creating an equipotential region that electrically shields the resistance layer from noise sources. By establishing this equipotential barrier, the design simplifies noise suppression without requiring complex feedback or active control mechanisms.
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 configuration enhances the accuracy and sensitivity of gas detection by effectively suppressing noise in the signal, allowing for reliable detection of gas concentrations and states.
Implementation Method 1
a first electrical resistance of the first resistance layer is configured to change according to a state of a detection target around the first element
Implementation Method 2
a first conductive member provided between the first resistance layer and the first conductive layer. A potential of the first conductive member is fixed
Data Source
AI summary
According to one embodiment, a sensor includes an element section including a first base and a first element. The first element includes a first fixed member fixed to the first base, a first connecting member supported by the first fixed member, and a first film portion supported by the first connecting member. A first gap is provided between the first base and the first film portion. The first film portion includes a first resistance layer, a first conductive layer, and a first conductive member provided between the first resistance layer and the first conductive layer. A potential of the first conductive member is fixed. A first electrical resistance of the first resistance layer is configured to change according to a state of a detection target around the first element.