Optical Particle Sensor with Focal Plane Photodetector Arrays
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Solution Overview
Problem
Current optical particle detection methods are complex, expensive, and lack robustness, making them unsuitable for low-cost, portable applications such as air quality control and fire detection, and they struggle to accurately determine the nature of particles.
Innovation Solution
A detector system with a channel for particles and a network of photodetectors, where each optical system converges light rays diffused by particles to a focal image plane, allowing all rays from parallel directions to converge to a single point, reducing the blind area and increasing the diffraction diagram's accessibility, thereby enhancing detection accuracy and analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical particle detection methods are used, then particle detection capability is achieved, but device complexity and cost increase significantly
Solution Approach 1:
The detection system is segmented into multiple independent photodetector arrays, each responsible for detecting scattered light at specific angles. This segmentation allows parallel detection of multiple scattering patterns simultaneously, maintaining comprehensive particle analysis capability while distributing system complexity across modular components rather than requiring a single complex detection mechanism
Solution Approach 2:
The photodetector arrays serve multiple functions: they detect scattered light intensity, determine scattering angles, and collectively reconstruct complete particle scattering patterns. This multi-functionality eliminates the need for separate specialized components for each detection task, reducing overall device complexity while maintaining comprehensive particle detection capability
2Measurement precision
If goniometer with rotating photodetector arm is used for angular scattering measurement, then particle concentration can be determined, but device becomes expensive and non-robust
Solution Approach 1:
The system replaces the dynamic rotating goniometer mechanism with a static array of photodetectors positioned at fixed angles. This static configuration eliminates mechanical moving parts while maintaining the ability to measure scattering at multiple angles simultaneously, significantly improving robustness and reducing complexity while preserving measurement precision
Solution Approach 2:
The system transitions from one-dimensional angular measurement (single photodetector moving through angles) to two-dimensional angular space measurement (array of photodetectors covering multiple angles simultaneously). This dimensional expansion allows complete scattering pattern capture without mechanical movement, eliminating the need for complex rotating mechanisms while enhancing measurement capability
3Measurement precision
If discrete array of photodetectors is used for scattering measurement, then particle analysis is enabled, but device robustness decreases and portability becomes difficult
Solution Approach 1:
Multiple photodetector arrays are merged into a single integrated detection system with a common light source and shared signal processing electronics. This consolidation reduces the number of independent subsystems, improving overall system robustness and facilitating portability while maintaining the precision of particle parameter analysis through the combined detection capability of all arrays
4Measurement precision
If complete scattering pattern collection is implemented, then particle nature determination accuracy improves, but device complexity increases
Solution Approach 1:
The system uses multiple photodetector arrays to capture copies of the scattering pattern at different angular positions simultaneously. Each array records a portion of the complete scattering pattern, and these copies are computationally reconstructed into the full pattern. This copying approach enables comprehensive particle nature determination while keeping individual detector arrays relatively simple and the overall optical system manageable
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 configuration improves the accuracy and sensitivity of particle detection while reducing complexity and cost, enabling quick and precise analysis of particle nature, even in the absence of a pump, and is suitable for various applications including air quality and fire detection systems.
Implementation Method 1
If particles are present in the illuminated area, they will both absorb the light from the source and deflect it away from the main direction of propagation, a phenomenon known as scattering
Implementation Method 2
Each optical system is convergent so as to converge the light rays from the source and not scattered by the particles towards an image focus located on the image focal plane
Implementation Method 3
at least one array of photodetectors configured so that at least some of the photodetectors receive light rays from the source and scattered by the particles present in the channel
Data Source
Figure 1~2
Figure 3
Figure 4a~4b
AI summary
The present invention relates to a particle detector comprising at least: ∘ at least one channel (20) intended to receive at least one fluid comprising particles (60) and configured to receive at least one light beam (111a, 111b) emitted by a light source (210); ∘ at least one array (230) of photodetectors (231) configured such that at least some of the photodetectors (231) receive light beams emitted by the source and scattered by the particles (60) present in the channel (20); characterized in that: ∘ the detector further comprises at least one optical system (15), ∘ each optical system (15) is associated with an array (231) of photodetectors (231) and has at least one image focal plane (151) and one optical axis (152), ∘ the detector is configured so that said image focal plane (151) of the optical system (15) is optically coupled to the array (230) of photodetectors (231).