Curved Flow Cell Reflector for High NA Particle Detection
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Solution Overview
Problem
Conventional particle counters with a planar flow cell and separate collection optics suffer from limited numerical aperture, leading to non-linear response curves as particle size increases, making them ineffective in the Mie regime, and fail to detect smaller particles without introducing spherical aberration.
Innovation Solution
A 90-degree light scatter collection optics system with an optional lens and reflector in the flow cell, where the reflector redirects scattered light back to the center, increasing numerical aperture and light gathering capability without aberration, allowing for improved detection of particles across various size regimes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a planar flow cell with separate collection optics is used, then the instrument structure is simple and easy to manufacture, but the numerical aperture is limited causing non-linear response in Mie regime
Solution Approach 1:
The patent merges the flow cell and collection optics into an integrated structure where the flow cell itself acts as part of the optical collection system. The curved surfaces of the flow cell are optimized to simultaneously contain the fluid and collect scattered light, eliminating the need for separate collection optics and increasing numerical aperture while maintaining manufacturing simplicity
Solution Approach 2:
The patent transitions from a planar flow cell geometry to a three-dimensional curved geometry. The flow cell features curved entry and exit surfaces that are optimized for both fluid flow and light collection, adding dimensional complexity to improve numerical aperture and response linearity across different particle size regimes
2Measurement precision
If the numerical aperture is increased to detect smaller particles, then particle sensitivity improves, but spherical aberration is introduced degrading measurement quality
Solution Approach 1:
The patent applies different optical properties to different regions of the flow cell. The entry and exit surfaces have specifically optimized curvatures that vary across their areas, with each region designed to minimize spherical aberration while contributing to high numerical aperture. This local optimization allows increased particle sensitivity without degrading measurement quality
Solution Approach 2:
The patent optimizes specific geometric parameters of the flow cell, including the curvature radii of the entry and exit surfaces, to achieve the desired balance between numerical aperture and aberration control. By carefully selecting and adjusting these parameters, the system achieves high particle sensitivity while maintaining measurement accuracy
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 solution provides improved response linearity and increased sensitivity for detecting particles, enabling effective detection of smaller particles and maintaining linearity through both Rayleigh and Mie scatter size regimes.
Implementation Method 1
the reflector redirects scattered light back to the center, increasing numerical aperture and light gathering capability
Implementation Method 2
The Flow Cell Lens serves to increase the light gathering capability of the 90 Degree Collection Optics without aberration
Implementation Method 3
light scattered in its direction back to the center of the flow cell making the light available for the collection system
Data Source
AI summary
A device (FIG. 2) that uses light to detect particles in fluid is disclosed. The device incorporates a lens and reflector on a flow cell to increase the numerical aperture of a subsequent light collection system without any increase in spherical aberration.