Particle Characterization by Light Diffraction with Asymmetry Filtering
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Solution Overview
Problem
Conventional particle characterization instruments using light diffraction struggle with accurately determining particle size distribution due to inhomogeneities in the dispersant medium, such as thermal or pressure variations, and contaminants, which cause random scattering patterns difficult to distinguish from particle scattering.
Innovation Solution
The method involves identifying and rejecting measurement contributions from light scattered by inhomogeneities in the dispersant by analyzing the asymmetry and temporal characteristics of the scattered light, using a detector array arranged to detect asymmetry about the illumination axis and processing the data to separate particle peaks from spurious peaks, thereby improving the accuracy of particle size distribution calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional light diffraction measurement is used to characterize particles, then particle size distribution can be obtained, but measurement accuracy deteriorates due to scattering from inhomogeneities in the dispersant medium
Solution Approach 1:
The patent applies asymmetry by arranging detector elements at different angular positions about the illumination axis to detect asymmetric scattering patterns. Particle scattering produces symmetric patterns while inhomogeneity scattering produces asymmetric patterns, allowing differentiation and removal of spurious signals to improve measurement accuracy.
Solution Approach 2:
The patent extracts and removes the harmful scattering contribution from inhomogeneities by identifying asymmetric scattering patterns and subtracting them from the total measured scattering signal, leaving only the symmetric particle scattering data for accurate particle size distribution calculation.
2Reliability
If thermal or pressure variations are minimized by waiting for equalisation in a temperature controlled environment, then measurement stability improves, but measurement time increases excessively or settling does not occur
Solution Approach 1:
The patent transitions from a static approach (waiting for thermal equilibrium) to a dynamic approach by continuously monitoring scattering patterns and actively identifying/removing inhomogeneity contributions in real-time, allowing measurements to proceed without prolonged settling periods while maintaining reliability.
Solution Approach 2:
The patent changes the measurement parameter from waiting for environmental parameter stabilization (temperature, pressure) to directly measuring and compensating for the optical effect (scattering patterns), enabling measurements under varying environmental conditions without excessive settling time.
3Device complexity
If no filtering is used to remove fluorescent light, then measurement complexity is reduced, but spurious scattering from inhomogeneities cannot be distinguished from particle scattering
Solution Approach 1:
The patent uses asymmetry as a discrimination parameter, arranging detectors to detect the angular distribution of scattered light. Particle scattering produces symmetric angular patterns while inhomogeneity scattering produces asymmetric patterns, enabling signal discrimination without additional filtering hardware, thus maintaining simplicity while improving precision.
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 effectively removes spurious data from inhomogeneities, enhancing the accuracy of particle size distribution measurements and improving the signal-to-noise ratio, allowing for more precise characterization of particles even in challenging conditions.
Implementation Method 1
A diffraction based particle characterisation instrument works by measuring light scattered from particles
Implementation Method 2
method of characterising particles suspended in a fluid dispersant by light diffraction
Implementation Method 3
The detector elements are arranged to measure the intensity of scattered light at a plurality of scattering angles
Data Source
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AI summary
A method of characterising particles (105) suspended in a fluid dispersant (104) by light diffraction, comprising: obtaining measurement data (108) from a detector element (107), the detector element (107) being arranged to measure the intensity of scattered light (106); identifying a measurement contribution arising from light scattered by inhomogeneities in the dispersant (104); processing the measurement data (108) to remove or separate the measurement contribution arising from light scattered by inhomogeneities in the dispersant (104); calculating a particle size distribution from the processed measurement; wherein identifying a measurement contribution arising from light scattered by inhomogeneities in the dispersant comprises identifying measured scattered light with predetermined temporal characteristics.