Miniaturized Temperature Humidity Sensor With Spiral Inductor Electrode
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Solution Overview
Problem
Existing temperature and humidity sensors face challenges in miniaturization due to the need for large electrode areas and thin moisture-sensitive films, which complicates manufacturing and reduces oscillation frequency precision, making them susceptible to parasitic capacitance and resistance components.
Innovation Solution
A temperature and humidity sensor design featuring a substrate with a first electrode and a linear second electrode that extends along the first electrode, with a moisture-sensitive film in between, where the second electrode forms an inductor and includes spiral wiring and a signal lead-out wiring section, allowing for a compact and high-precision oscillation circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the area of electrodes is enlarged to increase electrostatic capacitance, then the electrostatic capacity of the humidity sensor is improved, but the sensor size increases and miniaturization becomes difficult
Solution Approach 1:
The patent transitions from planar electrode arrangements to a three-dimensional stacked configuration. Multiple electrode pairs are arranged vertically on different layers of the substrate, allowing the electrostatic capacitance to be increased by utilizing the third dimension (height) rather than expanding the planar area. This enables miniaturization while maintaining sufficient capacitance for precise humidity measurement.
2Measurement precision
If the thickness of the moisture sensitive film is thinned to increase electrostatic capacitance, then the electrostatic capacity of the humidity sensor is improved, but the manufacturing difficulty increases
Solution Approach 1:
Instead of reducing film thickness to increase capacitance, the patent increases the number of electrode pairs in the vertical stacking direction. Each electrode pair contributes to the total electrostatic capacitance, allowing the use of standard-thickness moisture sensitive films while achieving high capacitance values through the cumulative effect of multiple layers.
3Measurement precision
If the intervals between linear electrodes are narrowed to increase electrostatic capacitance, then the electrostatic capacity of the humidity sensor is improved, but the manufacturing difficulty increases
Solution Approach 1:
The patent arranges electrode pairs in multiple stacked layers with standard spacing between them. The increased electrostatic capacitance is achieved by having multiple such pairs in vertical succession rather than by narrowing the horizontal intervals between linear electrodes, thus maintaining ease of manufacturing while improving measurement precision.
4Device complexity
If a CR oscillation circuit is used, then the circuit configuration is simplified, but the oscillation frequency precision is low and the circuit is susceptible to parasitic capacitance and resistance components
Solution Approach 1:
The patent combines the humidity sensing function with the oscillation circuit function by integrating the electrode pairs directly into the oscillation circuit structure. The electrostatic capacitance of the moisture sensitive film is utilized as the frequency-determining capacitance element, merging the sensing element with the circuit component to achieve both simplified configuration and high precision.
5Area of stationary object
If the sensor is miniaturized, then the sensor size is reduced, but the electrostatic capacitance decreases and manufacturing becomes more difficult
Solution Approach 1:
The patent achieves miniaturization by stacking electrode pairs vertically rather than expanding them horizontally. This three-dimensional arrangement concentrates the sensing elements within a small planar footprint while maintaining sufficient electrostatic capacitance through the cumulative effect of multiple vertically stacked electrode pairs.
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 design enables the creation of a miniaturized temperature and humidity sensor with high precision, enhancing sensitivity and manufacturing ease while maintaining effective humidity detection capabilities.
Implementation Method 1
detect humidity based on a change in magnitude of resistance or electrostatic capacity
Implementation Method 2
the second electrode forms an inductor
Data Source
AI summary
A temperature and humidity sensor includes a substrate, a first electrode provided on the substrate, a linear second electrode at least part of which is so provided as to extend along the first electrode, and a moisture sensitive film provided between the part of the second electrode extending along the first electrode and the first electrode. The second electrode has a section that is formed in a spiral shape when viewed from above so as to form an inductor. With this, a precise oscillation circuit can be configured so that a temperature-humidity sensor small in size and capable of being easily manufactured can be provided.