Optical Particle Sizing via Dynamic Focal Point Scanning
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Solution Overview
Problem
Existing optical measurement technologies struggle to accurately measure the size distribution of particles performing Brownian motion in a three-dimensional space, as they fail to account for the depth direction of the particles.
Innovation Solution
The proposed solution involves a size distribution measurement device and method that scans the focal point position of measurement light faster than the Brownian motion speed of particles, allowing for accurate tracking and sizing of particles in the Z-axis direction, and utilizes reflected light intensity to calculate particle size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical measurement is performed on particles performing Brownian motion in three-dimensional space, then particle size distribution can be measured, but measurement accuracy deteriorates due to particle movement in the depth direction
Solution Approach 1:
The patent applies dynamics by making the measurement system adaptive to particle motion. The focal point position is dynamically adjusted to track particles performing Brownian motion, allowing continuous measurement despite particle movement in the depth direction. This dynamic tracking capability resolves the contradiction between maintaining measurement accuracy and dealing with unreliable stationary assumptions.
Solution Approach 2:
The patent transitions from two-dimensional plane position measurement to three-dimensional measurement by adding depth direction (Z-axis) focal point positioning. This dimensional extension allows the system to account for particle movement in the depth direction, thereby improving measurement reliability for particles performing Brownian motion in three-dimensional space.
2Measurement precision
If measurement light is not scanned in the depth direction, then measurement system complexity is reduced, but particle size measurement becomes difficult
Solution Approach 1:
The patent implements dynamic focal point position adjustment along the optical axis to track particles in the depth direction. This dynamic capability enables particle size measurement by capturing optical signals at different depth positions, resolving the contradiction between measurement capability and system complexity through adaptive tracking rather than exhaustive scanning.
Solution Approach 2:
The patent changes the focal point position parameter along the optical axis to measure particles at different depth positions. By varying this parameter dynamically rather than using fixed focal planes, the system achieves particle size measurement capability without requiring complex multi-plane scanning mechanisms.
3Measurement precision
If photodetection region moves faster than Brownian motion speed, then particle tracking accuracy is improved, but measurement time increases
Solution Approach 1:
The patent implements dynamic tracking where the photodetection region moves at speeds matching particle Brownian motion. This dynamic adjustment allows accurate tracking without requiring excessively fast scanning speeds, thereby reducing measurement time while maintaining tracking accuracy through adaptive velocity matching.
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 quantitative measurement of the size distribution of particles in a three-dimensional manner, effectively overcoming the limitations of previous technologies by accurately accounting for particle movement and depth positioning.
Implementation Method 1
scans the focal point position of measurement light faster than the Brownian motion speed of particles, allowing for accurate tracking and sizing of particles in the Z-axis direction
Implementation Method 2
utilizes reflected light intensity to calculate particle size
Data Source
Figure 1(a)~1(c)
Figure 2(a)~2(b)
Figure 3
AI summary
An object of the present invention is to provide an optical measurement technology capable of quantitatively measuring a size distribution of a particle that performs Brownian motion in a sample. A size distribution measurement device according to the present invention measures a reflected light intensity while scanning a focal point position along an optical axis direction of measurement light, and calculates the size distribution of the particle according to the highest reflected light intensity of the measured reflected light intensities (refer to Fig. 9).