Dielectrophoretic Particle Counting Through Aggregate Dispersion
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Solution Overview
Problem
Conventional methods for counting dielectric particles using dielectrophoresis fail to accurately count large numbers due to false negatives caused by particle aggregation, leading to undercounting.
Innovation Solution
A method involving the application of first-direction dielectrophoretic force to aggregate particles, followed by second-direction dielectrophoretic force to disperse them, allowing for accurate counting based on captured dispersion images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dielectrophoresis is used to collect dielectric particles in slit areas, then particle counting can be performed, but false negatives occur when a large number of particles exist, leading to inaccurate counting
Solution Approach 1:
The invention divides the particle collection process into multiple stages: first collecting particles in initial slit areas, then collecting remaining particles in second slit areas positioned at different locations. This segmentation prevents particle aggregation in single areas and enables accurate counting of large numbers of particles by distributing them across multiple collection zones.
Solution Approach 2:
The invention introduces a spatial dimension to particle collection by positioning multiple sets of slit areas at different locations within the measurement region. Instead of collecting all particles in a single area, particles are collected in different spatial zones, preventing aggregation and enabling accurate counting through multi-dimensional distribution.
2Quantity of substance
If particles are aggregated by first-direction dielectrophoretic force, then particles can be concentrated for imaging, but false negatives occur due to aggregation causing undercounting
Solution Approach 1:
The invention applies dielectrophoretic force in opposite directions at different time stages: first in a first direction to aggregate particles for initial imaging, then in a second direction (opposite to the first) to disperse the aggregated particles. This inversion prevents permanent aggregation and enables accurate counting by alternating between concentration and dispersion states.
Solution Approach 2:
The invention employs periodic application of dielectrophoretic force with alternating directions: aggregating particles in the first direction, imaging, then dispersing in the second direction, and repeating the cycle. This periodic action ensures particles are properly distributed for accurate counting while maintaining the ability to concentrate them when needed for imaging.
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
Reduces false negatives by dispersing aggregated particles, enabling more accurate counting of dielectric particles.
Implementation Method 1
aggregating particles in a sample by action of first-direction dielectrophoretic force
Implementation Method 2
dispersing the aggregated particles by action of second-direction dielectrophoretic force
Data Source
AI summary
A counting method includes aggregating particles in a sample by action of first-direction dielectrophoretic force, dispersing the aggregated particles by action of second-direction dielectrophoretic force, which is different from the first-direction dielectrophoretic force, capturing a dispersion image including the dispersed particles, and determining the number of particles on the basis of the dispersion image.