Miniaturized Gas Sensor Series-Connected Units
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current miniaturized NOx gas sensors face challenges in achieving high sensitivity and low power consumption while maintaining a compact size, due to limitations in surface area to volume ratio and internal resistance, which hinders their effectiveness in portable and high-temperature applications.
Innovation Solution
A microfabricated gas sensor device with a base substrate, electrolyte layer, and potentiometric sensor units featuring tungsten oxide (WO3) sensing electrodes and platinum (Pt) reference electrodes, connected in series to enhance sensitivity, and optimized surface area ratios to minimize internal resistance and improve signal response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the sensor size is reduced using MEMS techniques, then the device size and power consumption decrease, but the surface area decreases leading to decreased signal strength
Solution Approach 1:
The sensor is divided into multiple sensor units (e.g., 5 units) connected in series. Each unit contributes to the overall signal, and the series connection amplifies the total output signal while maintaining a compact form factor suitable for MEMS integration.
Solution Approach 2:
Multiple sensor units are combined in a series configuration within a single MEMS device. This merging of functional elements increases the effective sensing surface area and signal output without proportionally increasing the device volume, thus resolving the contradiction between miniaturization and signal strength.
2Measurement precision
If multiple sensor units are connected in series to increase sensitivity, then the detection capability improves, but the internal resistance increases
Solution Approach 1:
The electrolyte layer thickness is optimized to balance ionic conduction and signal generation. By controlling the thickness parameter, the sensor achieves sufficient sensitivity from series-connected units while minimizing the increase in internal resistance. The tungsten oxide sensing electrode material is also selected for its optimal electrical properties at micro-scales.
3Measurement precision
If hand assembly techniques are used to fabricate sensors, then sensitivity can be achieved, but the minimum size is limited and manufacturing complexity increases
Solution Approach 1:
Manual hand assembly techniques are replaced with MEMS fabrication processes. This substitution enables precise control of sensor unit dimensions at the micrometer scale, allowing for miniaturization while maintaining sensitivity through standardized, repeatable manufacturing of multiple small sensor units that can be series-connected.
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 solution achieves increased sensitivity and reduced power consumption, enabling detection of NOx at low concentrations and operation across a broad temperature range, including high temperatures, while reducing sensor size and cost through batch fabrication.
Implementation Method 1
solid-state electrochemical sensors being one such technique
Implementation Method 2
an electrolyte layer disposed on the base substrate
Data Source
AI summary
Various embodiments of a gas sensor device and method of fabricating a gas sensor device are provided. In one embodiment a gas sensor device includes a base substrate, an electrolyte layer disposed on the base substrate and a plurality of potentiometric sensor units electrically coupled to the base substrate. Each potentiometric sensor unit includes an electrolyte layer disposed on the base substrate, a sensing electrode comprising tungsten oxide (WO3) and platinum (Pt), a reference electrode comprising Pt, and a plurality of connectors coupled to the plurality of potentiometric sensors to connect the plurality of potentiometric sensors in series.