Gas Sensor With Phononic Crystal Support Layer
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Solution Overview
Problem
Existing gas sensors face challenges in reducing power consumption, particularly for multi-sensor technologies, which affects their ability to perform continuous monitoring and maintain detection accuracy in environments with interference gases.
Innovation Solution
A gas sensor design featuring a substrate with a cavity, a support layer with a phononic crystal structure, and a gas sensing layer that is heated efficiently using a resistance heating wire, reducing thermal conductivity and enabling low-power operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional gas sensor design is used, then the sensor can detect target gases, but the power consumption is high (e.g., 120 mW for hydrogen sensor SB-19)
Solution Approach 1:
The sensor structure is segmented into distinct functional layers: a substrate with cavity, a support layer with phononic crystal structure, a base layer, a heater layer, and a gas sensing layer. This segmentation allows each layer to perform its specific function efficiently, contributing to overall low power consumption while maintaining reliable operation.
Solution Approach 2:
The phononic crystal structure is applied locally to the support layer in the portion contacting the cavity, creating regions with different thermal properties. This local modification of thermal conductivity allows heat to be retained where needed (at the gas sensing layer) while reducing overall power consumption, enabling continuous monitoring with lower energy input.
2Measurement precision
If the gas sensing layer is heated continuously, then detection accuracy is maintained, but power consumption increases
Solution Approach 1:
The heater layer is designed to operate with periodic heating cycles rather than continuous heating. The phononic crystal structure in the support layer helps maintain thermal energy during the heating cycles, allowing the gas sensing layer to reach and maintain the necessary temperature for accurate detection while the heater can be cycled on and off, significantly reducing average power consumption.
Solution Approach 2:
The phononic crystal structure changes the thermal conductivity parameters of the support layer, creating a thermal environment that retains heat more effectively. This parameter change allows the system to maintain detection accuracy at lower average temperatures and with shorter heating durations, reducing power consumption while preserving measurement precision.
3Use of energy by moving object
If a phononic crystal structure is added to reduce thermal conductivity, then power consumption is reduced, but device complexity increases
Solution Approach 1:
The phononic crystal structure introduces asymmetric patterning to the support layer, creating a structure that is more complex in one aspect (the patterned support layer) but simpler in others (reduced need for additional insulation layers or complex heating control systems). This asymmetric approach achieves low thermal conductivity with a relatively straightforward implementation.
Solution Approach 2:
The phononic crystal structure in the support layer serves multiple functions: it provides mechanical support, manages thermal conductivity, and contributes to the overall structural integrity of the sensor. This multi-functionality reduces the need for separate components, offsetting the added complexity with consolidated design benefits.
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 design achieves significant reductions in power consumption, allowing for continuous monitoring and improved detection accuracy by effectively heating the gas sensing layer with reduced thermal conductivity, enabling battery-driven operation and enhanced reliability.
Implementation Method 1
The support layer has a first phononic crystal structure in a portion in contact with the cavity
Implementation Method 2
a heater layer disposed on or above the base layer
Data Source
AI summary
A gas sensor includes a substrate, a support layer, a base layer, a heater layer disposed on or above the base layer, a gas sensing layer that is disposed on or above one of the heater layer and the base layer and that has a gas concentration dependent electrical impedance, and a detection electrode that is electrically connected to the gas sensing layer and that detects the impedance of the gas sensing layer. The substrate has a cavity and an opening formed by the cavity. The support layer is disposed on the substrate so as to cover at least an entire periphery of the opening. The base layer is supported by the support layer above the cavity so as to be separated from the substrate. A portion of the support layer in contact with the cavity has a first phononic crystal structure structured by a plurality of regularly arranged through-holes.