Folded Optical Flow Cell for Photometric Analysis
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Solution Overview
Problem
Existing photometric analysis flow cells face challenges with backscattering noise and bulky fiber optic cable packaging due to large bend radii, leading to reduced signal-to-noise ratio and space constraints in compact applications.
Innovation Solution
A flow cell with a folded optical path and center divider, featuring co-located, collinear fiber optic cables that eliminate backscattered light and allow for compact, rugged packaging by separating fluid passages during light passes, enabling improved optical performance and reduced cable looping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a cross flow cell configuration is used with fiber optic cables on opposite sides, then optical signal performance is improved by eliminating backscattering, but cable packaging becomes bulky due to large minimum bend radius requirements
Solution Approach 1:
The flow cell is divided into two separate flow paths (first and second flow paths) that are spatially separated by a partition wall. This segmentation allows the fiber optic cables to be positioned in different regions, enabling compact routing while maintaining the transmission configuration that eliminates backscattering interference.
Solution Approach 2:
The invention transitions from a planar cross configuration to a three-dimensional arrangement where the optical path is folded back through the fluid. The light travels through the first flow path, reflects off a mirror, and returns through the second flow path, creating a compact folded geometry that reduces the spatial footprint while maintaining optical performance.
2Reliability
If fiber optic cables are routed with large loops to satisfy minimum bend radius, then cable reliability is improved by avoiding fiber breakage, but device complexity increases due to excessive cable looping
Solution Approach 1:
The flow cell body is partitioned into distinct regions that accommodate the fiber optic cables at different locations. The first and second optical ports are positioned to allow cables to enter at separate points, enabling shorter, more direct routing paths that satisfy bend radius requirements without excessive looping.
Solution Approach 2:
The folded optical path configuration positions the optical ports and cables in a three-dimensional arrangement that reduces the horizontal spread of cable routing. By folding the light path back through the cell, the cables can be routed more compactly while maintaining adequate bend radii.
3Volume of moving object
If a folded optical path with co-located fiber optic cables is used, then cable packaging becomes compact and rugged, but backscattered light may interfere with measurements
Solution Approach 1:
A partition wall divides the flow cell into two separate flow paths, physically separating the regions where backscattered light could interfere with the detection. The first and second flow paths are spatially distinct, allowing the detection optics to be positioned where they are not exposed to backscattering from the illumination region.
Solution Approach 2:
The folded optical path uses a mirror to redirect light back through a separate flow path rather than returning through the same path. This spatial separation in the folded configuration ensures that the detection fiber does not receive backscattered light from the illumination region, eliminating interference while maintaining compact packaging.
4Measurement precision
If transmission flow cell configuration is used, then optical signal performance is improved by eliminating backscattering, but fiber optic cables must be positioned on opposite sides increasing packaging difficulty
Solution Approach 1:
The flow cell is segmented into two flow paths with optical ports positioned to accommodate cable routing. The partition wall creates distinct regions that allow cables to be packaged more easily while maintaining the transmission configuration for optimal optical performance.
Solution Approach 2:
The folded optical path configuration brings the cable connection points closer together in space by folding the light path back through the cell. This three-dimensional arrangement allows co-located or near-co-located cable positions while maintaining the transmission geometry that eliminates backscattering.
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 minimal backscattered stray light, a well-defined optical path length, and compact fiber optic cable packaging, enhancing measurement accuracy and ease of use in space-constrained environments.
Implementation Method 1
Attenuation of the transmitted light is caused by absorption or scattering of light by the fluid or by particles suspended in the fluid
Implementation Method 2
Attenuation of the transmitted light is caused by absorption or scattering of light by the fluid or by particles suspended in the fluid
Implementation Method 3
The light passes through the sample, is reflected off a pair of turning mirrors and returns through the fluid for a second pass
Data Source
AI summary
A flow cell and method for photometric transmission measurements are disclosed in which a folded optical path provides for co-located, collinear fiber optic read and illumination cables that can be bundled together. Light passes through a fluid sample, is reflected off a pair of right-angle turning mirrors and returns through the fluid for a second pass. A center divider separates fluid passages on the first pass of the light through the fluid and the second pass of the light through the fluid to block any undesired backscattered light from reaching a detector.