Multi-Camera Nanoparticle Detection with Calibration Mask Alignment
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Solution Overview
Problem
Conventional methods for detecting nanoparticles in polydisperse samples face challenges in accurately resolving particle sizes due to varying light scattering intensities, leading to errors in concentration measurement, and existing systems struggle with aligning multiple detectors to record the same region of interest.
Innovation Solution
A system utilizing multiple light sources and greyscale cameras, with a calibration mask and processor, to simultaneously record light scattered at different wavebands, allowing for precise alignment and accurate counting of nanoparticles by determining calibration corrections based on calibration marks, ensuring all cameras capture the same region of interest.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple detectors are used to record light scattered at different wavebands, then measurement precision for different particle sizes is improved, but alignment accuracy between detectors deteriorates
Solution Approach 1:
The patent applies preliminary action by capturing an alignment mark image before the actual nanoparticle measurement. The alignment mark contains known geometric features that are imaged under the same optical conditions as the nanoparticle measurements. This pre-captured reference image enables subsequent computational alignment of multiple detector images without requiring physical realignment, thus resolving the alignment accuracy deterioration issue while maintaining multi-wavelength measurement precision.
Solution Approach 2:
The patent uses a virtual copy of the alignment mark embedded in the calibration structure. Instead of physically adjusting multiple detectors to align perfectly, the system creates a digital copy of the alignment mark pattern that can be computationally processed to determine relative positions of all detectors. This virtual copying approach eliminates the need for precise mechanical alignment while preserving measurement precision across all detectors.
2Measurement precision
If light scattering intensity is used to distinguish particle sizes, then particle size differentiation is improved, but measurement accuracy deteriorates due to signal saturation from larger particles
Solution Approach 1:
The patent segments the light scattering measurement into multiple wavelength channels, with each detector optimized for a specific wavelength range. By dividing the spectral range into segments and assigning dedicated detectors to each segment, the system avoids signal saturation from larger particles while maintaining the ability to differentiate particle sizes through wavelength-specific scattering patterns. This segmentation enables accurate concentration measurement across the entire size distribution.
Solution Approach 2:
The patent applies local quality by optimizing each detector for specific wavelength ranges and particle size ranges. Each detector is assigned a specialized role based on its spectral sensitivity and the local requirements of the measurement. This localized optimization ensures that small particles are detected with high precision using appropriate wavelength channels, while avoiding the saturation issues that would occur with a single detector capturing all wavelengths simultaneously.
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 precise and accurate detection of nanoparticle concentrations by ensuring all cameras capture the same volume, overcoming alignment issues and improving the accuracy of particle size distribution analysis.
Implementation Method 1
a calibration mask (95), the mask including at least two calibration marks (100), with a calibration light source (110) constructed to emit a calibration beam (112)
Implementation Method 2
observation of scattered light from the nanoparticles, usually at a 90-degree angle relative to the light sheet plane
Data Source
AI summary
A system and method are provided to observe and count particles in polydisperse solutions with dark field microscopy while distinguishing among particles of different sizes and accurately counting particles. A calibration mask, calibration light source, and multiple wavelengths of light are used. Opaque calibration marks on the transparent calibration mask define a region of interest. Multiple beams of various wavelengths are combined into a beam or a light sheet and the perpendicular component of scattered light from the specimen particles is then split into separate wavelengths and detected by separate sensors attuned to each wavelength. By calibrating the region of interest and measuring rotational and translational differences between images captured by differing sensors, the images may be aligned exactly and merged, enabling: i) removal of duplicate particles which yields more accurate particle counts, ii) more accurate estimation of the examined volume, and iii) accurate particle concentration measurements.