Particle Sizing via Brownian Motion with Defocus Error Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing FPT devices suffer from optical errors in the condensing optical system, leading to inaccuracies in particle size measurement due to magnification errors caused by defocusing, which affect the calculated movement amount of particles and their sizes.
Innovation Solution
A particle measuring device and method that corrects the movement amount of particles using pre-determined correction values to account for magnification errors from defocusing, allowing for accurate particle size determination by using a flow passage irradiation and scattered light condensation at specific positions, and employing a control computation unit to calculate and correct movement amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a condensing optical system is disposed at such a position as to be opposed to a sample flow direction, then only Brownian motion of particles can be observed without flow interference, but magnification errors occur due to defocusing that reduce measurement precision
Solution Approach 1:
The patent applies preliminary action by pre-calculating magnification error correction values for different defocus positions before actual particle measurement. The system stores these correction values and applies them during measurement to compensate for optical errors, thereby maintaining both reliable Brownian motion observation and precise particle size measurement.
Solution Approach 2:
The patent changes the parameter of magnification by introducing correction values that adjust for defocus-induced magnification errors. By varying the correction applied based on defocus position, the system compensates for optical errors and maintains measurement precision despite the optical configuration necessary for reliable observation.
2Measurement precision
If telecentric optical systems are used to eliminate magnification errors, then measurement precision improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent replaces the expensive and complex telecentric optical system with a simpler condensing optical system paired with software-based correction. Instead of using costly telecentric lenses, the system uses standard optics with pre-calculated correction values, effectively substituting hardware complexity with computational compensation.
Solution Approach 2:
The patent substitutes the mechanical/optical solution (telecentric optical system) with a computational solution (magnification error correction using pre-calculated values). This replaces complex optical mechanics with software-based error compensation, reducing device complexity while maintaining measurement precision.
3Adaptability or versatility
If the condensing optical system uses large apertures and angles to capture particle movement, then measurement capability improves, but optical errors and magnification variations increase
Solution Approach 1:
The patent changes the parameter of magnification by introducing position-dependent correction values that compensate for the magnification errors inherent in using large aperture optical systems. This allows the system to maintain both high adaptability in particle detection and precision in movement measurement through parameter correction.
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
The method enables precise measurement of particle sizes by correcting for magnification errors, improving accuracy and reducing the need for telecentric optical systems, thus enhancing the overall measurement precision.
Implementation Method 1
capturing light scattered from the particle by irradiating a sample with light
Implementation Method 2
light scattered from a particle contained in a sample passing through a detection region that is formed in a prescribed section of a flow passage is condensed at a position obtained by extending the prescribed section in a flow direction
Implementation Method 3
movement amount of the particle due to Brownian motion
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
In the present invention, irradiation light is radiated to a flow channel, and scattered light from particles included in a material passing through a detection region formed in a predetermined section is condensed at a position virtually extended in the flow direction of a sample and imaged at a predetermined frame rate. An amount of movement in the direction perpendicular to the flow direction of the particles due to Brownian motion is then calculated on the basis of a plurality of frame images. In order to correct an error in the amount of movement on an image, caused by magnification in a defocus position, the amount of movement is corrected using a correction value determined in advance, and the diameter of the particles is specified.