Light-Scattering Detection Device Aperture Optimization
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Solution Overview
Problem
Current multi-angle light scattering (MALS) detection devices face challenges in maintaining molecular weight and particle diameter precision due to variations in scattered light generation areas across different detector arrangement angles, especially when samples are non-uniformly distributed, leading to inaccurate peak shape analysis and reduced precision in chromatographic measurements.
Innovation Solution
A light-scattering detection device configuration that includes a transparent sample cell, a coherent light source, imaging optics, a slit plate to limit scattering angles, and aperture plates with adjustable widths based on detector positions, allowing for optimal light collection and minimizing the impact of detector arrangement angles on scattered light reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the solid angle of the detector is increased to efficiently receive scattered light, then the light reception efficiency is improved, but the angular resolution of each detector deteriorates
Solution Approach 1:
The patent transitions from horizontal detector arrangement to vertical detector arrangement, changing the spatial dimension of detection. This allows the detector to receive scattered light from a larger solid angle without compromising angular resolution, as the vertical positioning enables simultaneous capture of light from multiple scattering angles while maintaining precise angular discrimination capabilities
2Use of energy by moving object
If the detector size is increased to set a larger solid angle, then the light reception efficiency is improved, but the dark current increases
Solution Approach 1:
The patent introduces a lens as an intermediary optical element between the sample cell and the detector. The lens focuses and directs scattered light onto the detector surface, enabling efficient light collection with a smaller detector area, thereby maintaining high light reception efficiency while avoiding the increase in dark current that would result from using a larger detector
3Area of stationary object
If light is incident parallel to the flow path, then the solid angle in the horizontal direction can be set larger, but the accuracy is deteriorated at low scattering angles due to flow field turbulence
Solution Approach 1:
The patent employs an asymmetric detector arrangement where detectors are positioned at different vertical heights rather than symmetrically in the horizontal plane. This asymmetric configuration allows the detection system to capture scattered light at low scattering angles with high accuracy while maintaining a large effective solid angle, overcoming the limitations of parallel light incidence that suffer from flow field turbulence effects
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 configuration ensures consistent and precise molecular weight and particle diameter calculations by optimizing light reception across all detector positions, independent of detector arrangement angles, thereby maintaining precision in chromatographic measurements.
Implementation Method 1
a light source configured to emit coherent light to the sample cell
Implementation Method 2
an imaging optics configured to collect scattered light from the sample cell to a periphery thereof at different scattering angles
Data Source
AI summary
A light-scattering detection device includes a transparent sample cell, a light source for emitting coherent light onto the sample cell, an imaging optics for collecting scattered light from the sample cell to the periphery thereof at different scattering angles, a slit plate for limiting the scattering angle range, a detector for receiving collected light from the imaging optics, and an aperture plate for limiting, by the aperture width thereof, the width of the light received by the detector, the aperture plate being arranged in the detector with respect to the focal length of the imaging optics. A plurality of detection optics is arranged around the sample cell at equal intervals from the central axis of the sample cell. The aperture width of each aperture plate differs in accordance with the arrangement angle θ of each detector with respect to the sample cell.