Optical Chopper for Nanoparticle Size Resolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for measuring nanoparticle properties in polydisperse samples are inaccurate due to difficulties in resolving nanoparticles of different sizes and varying light scattering intensities, leading to errors in concentration and size distribution analysis.
Innovation Solution
A system utilizing an optical chopper with rotating filters to rapidly adjust light intensity synchronized with the sensor's frame rate, allowing for accurate detection and tracking of particles of varying sizes by alternating between different filter settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods measure light scattered from all nanoparticles simultaneously, then the measurement process is simple, but the ability to resolve nanoparticles of different sizes is poor
Solution Approach 1:
The patent segments the measurement process by dividing the light scattering detection into separate temporal intervals. Different size ranges of nanoparticles are measured sequentially at different time points, allowing resolution of polydisperse samples without requiring complex simultaneous multi-channel detection systems.
Solution Approach 2:
The patent employs periodic action by using a chopper to alternately block and transmit light at specific frequencies. This creates periodic illumination patterns that synchronize with the camera's frame rate, enabling temporal separation of scattering signals from different particle sizes through periodic modulation rather than continuous simultaneous measurement.
2Measurement precision
If the light source intensity is increased to detect small nanoparticles, then the detection sensitivity for small particles improves, but the large nanoparticles become oversaturated
Solution Approach 1:
The patent uses periodic action with a chopper to modulate the light source intensity at specific frequencies. By alternating the light on/off cycles synchronously with camera framing, the system can detect small nanoparticles during low-intensity phases without saturating large nanoparticles during high-intensity phases, achieving dynamic range optimization through time-separated measurement.
Solution Approach 2:
The patent applies dynamics by making the light source intensity time-dependent rather than static. The chopper creates dynamically varying intensity levels that adapt to different particle sizes during different time intervals, allowing the system to optimize detection for each particle size category separately without compromise.
3Reliability
If the light source intensity is decreased to avoid saturation of large nanoparticles, then the measurement of large particles remains accurate, but small nanoparticles become undetected
Solution Approach 1:
The patent employs periodic action by using a chopper to create alternating light intensity cycles synchronized with camera framing. During certain phases, reduced intensity allows accurate measurement of large nanoparticles without saturation, while during other phases, sufficient intensity enables detection of small nanoparticles, achieving comprehensive coverage through temporal separation.
Solution Approach 2:
The patent applies preliminary action by pre-modulating the light source with the chopper before the actual measurement. This preliminary intensity modulation creates predictable temporal patterns that allow the system to anticipate and prepare for different particle size detections, ensuring both small and large particles are captured at appropriate intensity levels.
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 precise determination of particle sizes and concentrations by optimizing light intensity for different size ranges, overcoming the limitations of wild varying scattered light intensities and improving measurement accuracy.
Implementation Method 1
a light source is directed at a sample and a portion of the light is allowed to scatter when illuminating particles within the sample
Implementation Method 2
The chopper includes a rotation structure with a first filter and a second filter. The first filter permits a different amount or a different type of electromagnetic radiation to pass there through than the second filter
Data Source
AI summary
The disclosure provides for a novel optical chopper that can rapidly change the intensity of light incident on a colloid under investigation. This helps recording various sizes of nanoparticles that scatter light with very different efficiencies (effective cross-sections), typically orders of magnitude different.