Multi-Wavelength Optical Particle Sensor for Smoke Discrimination
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Solution Overview
Problem
Existing smoke detectors face issues with false alarms, contamination, reduced sensitivity, bulkiness, and inability to discriminate between smoke and water vapor, as well as limited ability to analyze fire stages and progression.
Innovation Solution
A particle detector using multiple wavelength ranges of light, an optical sensor, and a controller to distinguish between different wavelengths, allowing for discrimination of particle sizes and types, and integrated into various devices for enhanced fire detection and prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single wavelength light source and sensor are used for smoke detection, then the device structure is simple, but it cannot discriminate between smoke particles and water vapor droplets
Solution Approach 1:
The detection function is segmented into multiple wavelength channels. The light source emits multiple wavelengths simultaneously, and the sensor distinguishes different wavelength ranges separately. This segmentation allows the system to measure scattering at different wavelengths to discriminate particle types based on their distinct scattering characteristics at each wavelength.
Solution Approach 2:
The optical detection system is designed with multi-functionality by using a single sensor that can detect multiple wavelength ranges. This universal approach allows the same sensor to perform discrimination between smoke and water vapor by analyzing scattering patterns across different wavelengths, eliminating the need for separate detection systems for each particle type.
2Measurement precision
If multiple sensors at different angles are used to discriminate particle sizes, then particle size discrimination is improved, but the device becomes bulkier and less compact
Solution Approach 1:
Instead of using multiple spatial dimensions (multiple sensors at different angles), the invention transitions to using the wavelength dimension for discrimination. A single sensor measures scattering intensity at multiple wavelengths, achieving particle size and type discrimination through spectral analysis rather than angular analysis, thereby maintaining a compact form factor.
3Reliability
If the detector chamber uses a labyrinth structure to block external light, then light interference is reduced, but air flow to the detector is reduced and the device becomes bulkier
Solution Approach 1:
The invention extracts the light blocking function from the complex labyrinthine chamber structure. By using a simpler chamber design combined with the multi-wavelength detection capability, the system achieves reliable detection without requiring elaborate light-blocking structures, thereby improving air flow and reducing device bulk while maintaining detection accuracy.
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 reduces false alarms, improves sensitivity and compactness, allows for accurate differentiation between smoke and water, and provides earlier detection of fire stages, enabling more effective countermeasures.
Implementation Method 1
The scattering of particles is highly dependent on the particle size. The size determines at which wavelength the particle will either scatter according to Mie or according Rayleigh scattering.
Implementation Method 2
The one or more light sources are collectively operable to simultaneously produce at least two wavelength ranges of emitted light
Data Source
AI summary
A particle detector. The particle detector comprises one or more light sources, an optical sensor, and a controller. The one or more light sources are collectively operable to simultaneously produce at least two wavelength ranges of emitted light. The optical sensor is configured to sense light of the at least two wavelength ranges emitted by the one or more light sources and to distinguish each range. The controller is configured to detect particles based on the light sensed by the optical sensor.