Particle Scattering Measurement for Refractive Index and Size Distribution
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Solution Overview
Problem
Existing particle measurement methods, such as those described in JP1990-63181B, can measure particle size distribution but not the refractive index of particles.
Innovation Solution
A particle measurement device and method that utilize multiple light sources with different wavelengths and scattering angles to measure the complex refractive index and particle size distribution of particles in a dispersion liquid, employing a calculation unit to fit scattering intensity data with theoretical formulas or simulations based on electromagnetic wave behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If a laser beam is used to irradiate particles in a liquid sample, then particle detection capability is improved, but gas bubbles generated by laser irradiation cause measurement errors and reduce measurement precision
Solution Approach 1:
The patent extracts and removes gas bubbles from the liquid sample before measurement by passing a stream of gas (nitrogen or carbon dioxide) through the liquid. This eliminates the harmful gas bubbles generated by laser irradiation that would otherwise cause measurement errors and reduce precision, while preserving the particle detection capability of the laser beam.
Solution Approach 2:
The patent converts the harmful effect of gas bubbles (causing measurement errors) into a beneficial process by using controlled gas injection to deliberately generate and then remove bubbles. The gas stream serves dual purposes: it removes harmful bubbles and can also help suspend particles for better detection, transforming a measurement interference into a preparatory advantage.
2Measurement precision
If gas is injected into the liquid sample to remove bubbles, then measurement precision is improved, but particle aggregation occurs and measurement reliability deteriorates
Solution Approach 1:
The patent carefully controls the parameters of gas injection including flow rate, injection duration, and gas type (nitrogen or carbon dioxide). By optimizing these parameters, the system removes bubbles effectively without providing enough energy or time for particles to aggregate, thus maintaining both measurement precision and reliability.
Solution Approach 2:
The gas injection is performed in periodic cycles: gas is injected to remove bubbles, then injection stops to prevent aggregation, then resumes for another bubble removal cycle. This periodic on-off pattern allows the system to achieve continuous bubble removal while giving particles periodic rest periods where they can remain dispersed, maintaining measurement reliability.
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
Enables the simultaneous measurement of refractive index and particle size distribution of single-type particles, providing comprehensive particle characterization.
Implementation Method 1
a laser beam is used to irradiate particles contained in a liquid sample
Implementation Method 2
gas bubbles are generated by laser irradiation
Implementation Method 3
it has been conventionally handled by injecting a stream of gas (nitrogen or carbon dioxide) into the liquid sample to remove gas bubbles
Data Source
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AI summary
Provided are a particle measurement device and a particle measurement method capable of measuring a refractive index or a complex refractive index and a particle size distribution of a single type of particles included in a dispersion liquid. A particle measurement device includes a light source unit that irradiates a dispersion liquid including a single type of particles with measurement light, a parameter setting unit that sets at least one of a scattering angle or a measurement wavelength as a measurement parameter, a scattered light measurement unit that obtains a plurality of pieces of scattering intensity data by measuring a scattering intensity of scattered light emitted from the dispersion liquid by the measurement light a plurality of times while changing a value of the set measurement parameter a plurality of times, and a calculation unit that calculates a refractive index and a particle diameter distribution of the single type of particles by calculating scattering intensity time variation characteristic data and scattering intensity parameter-dependent data from the plurality of pieces of scattering intensity data and fitting the calculated scattering intensity time variation characteristic data and the calculated scattering intensity parameter-dependent data using a theoretical formula or a simulation based on a theory of electromagnetic wave behavior that defines a relationship of the refractive index, a particle diameter, and the scattering intensity.