Multi-Wavelength Light Scattering for Particle Size Air Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing air quality sensors, such as smoke detectors, do not provide information on particle size and mass concentration, limiting their ability to offer comprehensive air quality measurements.
Innovation Solution
An air quality sensing system utilizing two light sources with different wavelengths, oriented to provide pre-configured scattering angles, processes light scattering measurements to estimate particle size and mass concentration, leveraging existing optical hardware like LEDs and photodiodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional light scattering measurement devices are used, then the presence of particles can be detected, but air quality measurements like particle size and mass concentration cannot be provided
Solution Approach 1:
The patent makes existing smoke detector optical hardware (LEDs and photodiodes) perform multiple functions by using multiple wavelengths of light. The same optical components that detect smoke presence are also used to measure particle size and mass concentration, enabling air quality monitoring without additional specialized hardware.
Solution Approach 2:
The patent changes the wavelength parameter of the light source to enable different measurement capabilities. By using multiple wavelengths (e.g., 850nm and 450nm LEDs), the system can differentiate between particle types and sizes, transforming a simple presence detector into a comprehensive air quality measurement device.
2Measurement precision
If multiple light sources with different wavelengths are used, then particle size and mass concentration can be measured, but device complexity increases
Solution Approach 1:
The patent reuses existing optical components (LEDs and photodiodes) for multiple measurement purposes. The same photodiode detects both smoke presence and particle characteristics when illuminated by different wavelengths, reducing the need for additional specialized sensors and simplifying the overall device architecture.
Solution Approach 2:
The patent combines multiple measurement functions (smoke detection, particle size measurement, mass concentration measurement) into a single integrated system using shared optical hardware. The processing circuit consolidates signals from multiple wavelengths to simultaneously determine various air quality parameters, reducing device complexity.
3Measurement precision
If specialized air quality sensing hardware is used, then accurate particle measurements can be obtained, but hardware cost and complexity increase
Solution Approach 1:
The patent enables existing smoke detector components to serve air quality measurement functions without requiring additional specialized hardware. The system uses the already-present LEDs and photodiodes, making the existing hardware work harder and smarter rather than adding more expensive components.
Solution Approach 2:
The patent makes commodity optical components (standard LEDs and photodiodes) perform specialized air quality measurement functions. By using multiple wavelengths with the same hardware platform, the system achieves accurate particle characterization at the cost of inexpensive, widely-available components rather than specialized 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
Enables accurate estimation of particle size and mass concentration, reducing hardware complexity and cost by utilizing existing smoke detector components, and improving measurement accuracy by minimizing ambient light interference.
Implementation Method 1
Light scattering can occur when light propagates through particles (e.g., smoke particles) in a space and scattered by the particles in the space
Data Source
AI summary
Techniques are described herein for air quality sensing. In some examples, the techniques are implemented as an apparatus including first and second light sources, a light detector having a detector output, and a processing circuit having a processing input coupled to the detector output and a processing output. The first light source is configured to generate a first light signal having a first wavelength. The second light source is configured to generate a second light signal having a second wavelength different from the first wavelength. The light detector is configured to generate a first detection signal at the detector output responsive to the first light signal and a second detection signal at the detector output responsive to the second light signal. The processing circuit is configured to generate a third signal representative of an air quality measurement at the processing output responsive to the first and second detection signals.