Humidity Sensor Using Charge Relaxation for Rapid Detection
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Solution Overview
Problem
Conventional humidity sensors face issues with rapid and accurate detection, reliability, and stability under high temperature and humidity conditions, often experiencing hysteresis, slow response, and degradation due to parasitic capacitance and moisture absorption by polymer films.
Innovation Solution
A humidity sensor utilizing a conductive material with electric charge relaxation effects, where charges are discharged based on surface resistance and capacitance changes, and a transistor structure with a hydrophobic layer and conductive material layer connected through a through-hole, allowing for rapid and accurate humidity detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a polymer-based humidity sensing film is used, then the sensor can detect humidity through moisture absorption, but the response rate is slow and hysteresis occurs
Solution Approach 1:
The patent changes the sensing mechanism from moisture absorption (chemical interaction) to surface conduction (physical interaction). By measuring changes in surface conductivity of the insulating layer rather than moisture absorption of polymer, the sensor achieves rapid response without hysteresis while maintaining accurate humidity detection through the relationship between surface conductivity and humidity levels.
Solution Approach 2:
The patent replaces the chemical absorption mechanism of polymer films with an electrical conduction measurement of surface properties. Instead of measuring capacitance change due to moisture absorption, the sensor measures surface conductivity changes of the insulating layer, which respond instantaneously to humidity changes without the slow absorption/desorption kinetics of polymer materials.
2Measurement precision
If a polymer-based humidity sensing film is used, then the sensor can detect humidity, but stability under high temperature and humidity conditions deteriorates
Solution Approach 1:
The patent replaces the vulnerable polymer sensing film with a semiconductor-based insulating layer that can be integrated into a standard transistor structure. This solid-state implementation eliminates the degradation issues of organic polymers under high temperature and humidity, providing long-term stable operation while maintaining humidity detection capability through surface conductivity measurements.
Solution Approach 2:
The patent uses a composite structure combining semiconductor materials (for the transistor and insulating layer) with metal electrodes. This composite approach leverages the electrical properties of semiconductors and the stability of metals to create a sensor that maintains reliable humidity detection under harsh environmental conditions, unlike pure polymer-based solutions.
3Ease of manufacture
If a conventional humidity sensing film structure is used, then the manufacturing process is simple, but parasitic capacitance distorts the signal and reduces reliability
Solution Approach 1:
The patent merges the humidity sensing function with the gate structure of a transistor. The insulating layer serves dual purposes as both the transistor gate dielectric and the humidity sensing element. This integration eliminates the need for separate sensing film deposition and reduces parasitic capacitance by using the transistor's inherent low-capacitance structure, while maintaining manufacturing simplicity through standard semiconductor fabrication processes.
Solution Approach 2:
The patent extracts the sensing function from a separate polymer film and embeds it within the transistor's insulating layer. This extraction eliminates the parasitic capacitance problems associated with thick polymer films while maintaining the ease of manufacture through standard semiconductor processing techniques for forming insulating layers and through-holes.
4Adaptability or versatility
If polymer material is used for humidity sensing, then the sensor can function in various environments, but the polymer is vulnerable to organic solvents and has adhesion problems with electrodes
Solution Approach 1:
The patent replaces the chemically vulnerable polymer material with a semiconductor-based insulating layer that is inherently resistant to organic solvents and environmental degradation. This solid-state material maintains versatility across different environments while eliminating adhesion problems through standard semiconductor fabrication techniques that ensure reliable metal-to-semiconductor interfaces.
Solution Approach 2:
The patent employs a composite structure of semiconductor insulating layer and metal electrodes, where the semiconductor material provides chemical stability and resistance to organic solvents. This composite approach maintains environmental adaptability while solving the adhesion and chemical vulnerability issues inherent in polymer-based sensors.
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 overcomes hysteresis, slow response, and stability issues, enabling rapid and accurate humidity detection in any medium, with improved reliability and mass production capabilities, and stability under varying conditions.
Implementation Method 1
A humidity sensor utilizing a conductive material with electric charge relaxation effects, where charges are discharged based on surface resistance and capacitance changes
Implementation Method 2
charges are discharged based on surface resistance and capacitance changes
Implementation Method 3
a hydrophobic layer covering the gate, the source and the drain
Data Source
AI summary
Disclosed is a humidity sensor including: a conductive material in which electric charges are charged; a charger which charges the electric charges in the conductive material; and a measurer which measures a change amount of the electric charges charged in the conductive material.