Particle Characterization Aperture Design for Large Particle Detection
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Solution Overview
Problem
Existing methods for characterizing large particles in suspensions predominantly composed of uniformly-sized fine particles are inefficient, leading to errors and statistical sampling issues due to the need for extensive dilutions, which can result in inaccurate reporting and increased experimental errors.
Innovation Solution
A method employing a device capable of characterizing particles according to the Coulter principle, where the suspension is prepared in an electrolyte and passed through an aperture with a diameter that allows for the characterization of large particles while minimizing the interference from small particles, thereby reducing the need for dilution and avoiding the coincidence effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If extensive dilutions are performed to characterize large particles in suspensions with fine particles, then measurement accuracy is improved, but experimental complexity and sampling errors increase
Solution Approach 1:
The patent applies local quality by using a large aperture that creates a localized measurement zone where large particles are selectively detected while small particles are excluded from the measurement volume. This allows accurate characterization of large particles without requiring dilution of the entire suspension, thereby reducing experimental complexity while maintaining measurement precision.
Solution Approach 2:
The patent segments the particle population into large particles (targeted for measurement) and small particles (excluded from measurement). By using an aperture sized to accommodate only large particles, the system separates the measurement function from the bulk suspension, allowing direct analysis without dilution and reducing sampling errors associated with extensive dilution procedures.
2Reliability
If extensive dilutions are performed to characterize large particles, then coincidence effect is reduced, but sampling errors and statistical reliability worsen
Solution Approach 1:
The large aperture creates a localized measurement zone that selectively detects large particles while excluding small particles from the measurement volume. This local selection mechanism ensures that each measurement event involves only large particles, eliminating the coincidence effect without requiring dilution, thereby maintaining statistical reliability and sampling accuracy.
Solution Approach 2:
The patent extracts the large particles from the mixed suspension for direct measurement using a large aperture. By taking out only the large particles into the measurement zone and excluding small particles, the system achieves accurate characterization without the need for extensive dilution, thereby avoiding the sampling errors and statistical issues that arise from diluting the entire suspension.
3Difficulty of detecting and measuring
If a large aperture is used to detect large particles, then detection sensitivity is improved, but interference from small particles increases
Solution Approach 1:
The patent applies local quality by creating a localized measurement zone with a large aperture that selectively detects large particles. The aperture size is specifically chosen to accommodate large particles while excluding small particles from the measurement volume, thereby achieving high detection sensitivity for large particles without interference from small particles.
Solution Approach 2:
The patent extracts large particles from the mixed suspension into the measurement zone using a large aperture, separating them from small particles. This extraction mechanism allows the system to detect large particles with high sensitivity while small particles are left outside the measurement zone, eliminating their interfering effect.
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 method enables accurate and efficient detection and characterization of large particles in various compositions, such as CMP slurries, pharmaceutical preparations, and toners, without the need for cumbersome dilutions, thereby reducing sampling errors and improving manufacturing processes.
Implementation Method 1
passing the prepared suspension, and a plurality of the particles therein, through an aperture of a device capable of characterizing particles according to the Coulter principle
Data Source
AI summary
Mixtures containing homogeneously-sized particles with a minimum concentration of agglomerates or larger particles are desired in various manufacturing processes such as, for example, in the manufacture and use of chemical mechanical polishing slurries, food emulsions, pharmaceutical products, paints, and print toner. The method disclosed herein provides these industries with an accurate and efficient method of screening such mixtures for such agglomerates and large particles. The method generally includes preparing a suspension of the mixture in an electrolyte, wherein the suspension includes a specified concentration of small particles per unit of electrolyte. The method further includes passing the prepared suspension, and a plurality of the particles therein, through an aperture of a device capable of characterizing particles according to the Coulter principle to obtain data on the particles. Still further, the method includes deriving a particle size distribution of the large particles from the obtained data. The suspension includes at least one small particle per aperture volume. The large particles have an average diameter that is at least five times greater than the average diameter of the small particles. The aperture has a diameter that is (i) at least 50 times greater than the average diameter of the small particles, and (ii) about 1.2 times greater than the average diameter of the large particles to less than about 50 times greater than the average diameter of the large particles.