Particle Sensor Electrode Spacing for PM Size Detection
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Solution Overview
Problem
Conventional capacitive-type particle sensors are highly sensitive to ambient temperature and moisture, requiring calibration and lacking the capability to accurately measure particle sizes, only allowing for relative changes in particle amounts to be detected.
Innovation Solution
A particle sensing device with a three-dimensional stacking electrode design, featuring multiple electrode pairs with varying distances, integrated into a substrate with a groove and through hole, allowing for precise measurement of particulate matter sizes and density, while being protected from external temperature and moisture influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If a capacitive-type particle sensor is used to detect particulate matter, then the sensor can measure changes in particle amount, but the sensor becomes highly sensitive to ambient temperature and moisture, requiring additional calibration
Solution Approach 1:
The sensor is divided into multiple independent sensing regions with different electrode spacing configurations. Each region independently detects particles of different size ranges, allowing the system to differentiate between PM2.5 and PM10 without being affected by environmental conditions. This segmentation enables size-specific detection while reducing cross-sensitivity to temperature and moisture variations.
Solution Approach 2:
Different regions of the sensor have locally optimized electrode spacing tailored to detect specific particle sizes. The first sensing region has smaller electrode spacing optimized for PM2.5, while the second region has larger spacing optimized for PM10. This local quality differentiation allows each region to be optimally tuned for its target particle size, improving detection accuracy while reducing environmental sensitivity.
2Device complexity
If a conventional capacitive particle sensor is used, then the device structure remains simple, but the sensor lacks the capability to accurately measure particle sizes, only allowing relative changes in particle amounts to be detected
Solution Approach 1:
The sensor transitions from a single-dimensional detection approach to a multi-dimensional sensing architecture by incorporating multiple sensing regions with different electrode spacing. This dimensional expansion in the sensor design enables simultaneous detection of different particle sizes (PM2.5 and PM10) while maintaining a relatively simple planar structure that can be integrated into portable devices.
Solution Approach 2:
The sensor achieves multi-functionality by detecting both PM2.5 and PM10 particles simultaneously using a single integrated device. The multiple sensing regions with different electrode spacing configurations enable the sensor to perform multiple detection functions (different particle size ranges) without requiring separate sensors, thus maintaining structural simplicity while enhancing measurement precision.
3Measurement precision
If temperature and moisture calibration is performed for the capacitive particle sensor, then measurement accuracy improves, but the device complexity and calibration requirements increase
Solution Approach 1:
The sensor is pre-configured with multiple sensing regions having different electrode spacing during manufacturing, which preliminarily establishes the detection capabilities for different particle sizes. This preliminary structural configuration reduces the need for complex runtime calibration, as the size differentiation capability is built into the hardware architecture rather than requiring software-based environmental compensation.
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
Enables accurate sizing and density measurement of particulate matter, improving device reliability and eliminating the need for temperature and moisture calibration, while being easily integrated into portable electronic devices.
Implementation Method 1
a particle sensing element 220... may include a first electrode pair 222 and a second electrode pair 224... Two first sub-electrodes 222a of the first electrode pair 222 are disposed opposite to each other... Two second sub-electrodes 224a of the second electrode pair 224 are disposed opposite to each other
Implementation Method 2
the particulate matters change a dielectric constant between the first electrode fingers 112 and the second electrode fingers 122 thereby correspondingly changing a capacitance therein
Data Source
AI summary
A particle sensing device, including a substrate and at least one particle sensing element, is provided. The substrate has a groove, and a through hole is disposed at a bottom of the groove. The through hole penetrates a bottom of the substrate. The particle sensing element is disposed in the substrate. The particle sensing element may include a first electrode pair and a second electrode pair. Two first sub-electrodes of the first electrode pair are disposed nearby two sides of the groove, respectively. And, a first distance is provided between the two first sub-electrodes. Two second sub-electrodes of the second electrode pair are disposed nearby two sides of the groove, respectively. And, a second distance is provided between the two second sub-electrodes. The first distance is smaller than the second distance.