Particle Sensor Dual-Path Light Splitting for Noise Suppression
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Solution Overview
Problem
Conventional particle sensors based on light extinction struggle to detect small particles in the nanometer and micrometer range due to limitations in intensity stability of the light beam, making it difficult to distinguish particle-induced attenuation from noise fluctuations.
Innovation Solution
The particle sensor splits the light beam into two partial beams, with one path through the measurement region and another as a reference, allowing for the calculation of a difference signal that suppresses intensity fluctuations, thereby improving the detection of small particles by enhancing the signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional light extinction detection is used, then the detection system is simple, but the ability to detect small particles is limited due to intensity fluctuations
Solution Approach 1:
The light beam is segmented into two separate paths: a measurement path that passes through the particle-laden flow and a reference path that does not. This segmentation allows the system to compare the measurement path intensity against the reference path intensity, thereby canceling out common-mode fluctuations and isolating the particle-induced attenuation signal.
Solution Approach 2:
A beam splitter is introduced as an intermediary component to divide the original light beam into two partial beams. The beam splitter enables the creation of the dual-path configuration without requiring two independent light sources, thus achieving fluctuation suppression while maintaining system simplicity.
2Measurement precision
If the light beam intensity is increased to improve signal strength, then small particles become more detectable, but intensity fluctuations also increase making detection harder
Solution Approach 1:
The system uses the reference path as a feedback mechanism to continuously monitor and compensate for light source intensity fluctuations. By comparing the reference path signal with the measurement path signal, the system can distinguish between fluctuations caused by the light source and those caused by particle attenuation, thereby maintaining measurement precision even with higher intensity beams.
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 approach enables the detection of small particles with improved accuracy by isolating the attenuation caused by particles from the noise, allowing for precise characterization of particle size and presence, even in harsh environments.
Implementation Method 1
a beam splitter unit (5) that is configured to split the light beam (3) into a first partial beam (3a) that propagates along a signal path (7a) and a second partial beam (3b) that propagates along a reference path (7b)
Implementation Method 2
a first photodetector (8a) arranged in the signal path (7a) to detect an intensity (I1) of the first partial beam (3a) and a second photodetector (8b) arranged in the reference path (7b) to detect an intensity (I2) of the second partial beam (3b)
Implementation Method 3
When a particle flows through a light beam that propagates through the measurement region with a pre-defined intensity distribution, the particle scatters, reflects and/or absorbs part of the intensity of the light beam
Implementation Method 4
the particle scatters, reflects and/or absorbs part of the intensity of the light beam
Data Source
Figure 1~3
AI summary
The invention relates to a particle sensor (1), comprising: a light source (2) configured to generate a light beam (3) propagating along a light path (4), a beam splitter unit (5) configured to split the light beam (3) into a first partial beam (3a) propagating along a signal path (7a) and a second partial beam (3b) propagating along a reference path (7b), the signal path (7a) passing through a measurement region (9) that is accessible to particles (P), a first photodetector (8a) arranged in the signal path (7) and configured to detect an intensity (I1) of the first partial beam (7a) after propagating through the measurement region (9), and a second photodetector (8b) arranged in the reference path (7b) and configured to detect an intensity (I2) of the second partial beam (3b), wherein the particle sensor (1) is configured to detect, in particular to characterize, particles (P) in the measurement region (9) based on a difference (I1 - I2) between the intensity (I1) of the first partial beam (3a) and the intensity (I2) of the second partial beam (3b). The invention also relates to a device comprising such a particle sensor (1) as well as to a corresponding method for detecting, in particular for characterizing, particles (P).