Optical Detection Assembly for Fluid Concentration Monitoring
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Solution Overview
Problem
Conventional optical detection assemblies for monitoring biological fluids in fluid flow circuits face issues due to varying refractive indices and inconsistent light transport through flexible plastic tubing, leading to inaccurate and inconsistent measurements of fluid properties, and the use of single photodiodes that cannot effectively capture dispersed light from turbid media.
Innovation Solution
An optical detection assembly featuring a light source, a light detector array, and a controller, where the light source is oriented to emit light into a vessel with a vessel attachment that has parallel faces to minimize refraction, and the light detector array receives and processes light intensity signals to determine substance concentration, improving measurement accuracy and consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If light is transmitted through flexible plastic tubing with varying refractive indices, then the optical detection assembly can be easily manufactured and installed, but the light transport becomes inconsistent leading to measurement errors
Solution Approach 1:
The invention extracts the problematic flexible plastic tubing from the optical path and replaces it with a rigid vessel having optically consistent properties. This removes the source of refraction variability while maintaining the fluid containment function, thereby resolving the contradiction between ease of manufacture and measurement precision.
Solution Approach 2:
The invention changes the refractive index parameter of the vessel wall material to match or closely approximate the refractive index of the biological fluid. This parameter matching minimizes refraction at the interface, ensuring consistent light transport while allowing for manufacturable solutions.
2Device complexity
If a single photodiode is used as the light detector, then the device complexity is reduced, but the dispersed light from turbid media cannot be fully captured
Solution Approach 1:
The invention segments the single photodiode detector into multiple photodiodes arranged in an array. Each photodiode captures a portion of the dispersed light, and their signals are combined to provide a complete measurement. This segmentation resolves the contradiction by enabling full capture of dispersed light while maintaining relatively simple device architecture.
Solution Approach 2:
The invention transitions from a single-point detection (0D/1D) to a distributed array detection (2D/3D spatial distribution). By arranging photodiodes in a two-dimensional array, the system captures light dispersed in multiple directions, effectively adding spatial dimensionality to the detection process and resolving the limitation of single photodiode detection.
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 more accurate and consistent optical monitoring of fluid properties by minimizing light refraction and effectively capturing dispersed light, leading to improved determination of substance concentrations in biological fluids.
Implementation Method 1
A light source is provided and oriented to emit a light into a fluid in a vessel. A light detector array is provided and oriented to receive at least a portion of the light exiting the vessel.
Implementation Method 2
when light 'L' is incident upon plastic tubing 'T ', the transport of light into the tubing lumen may vary according to Snell's Law depending on the refractive indices 'n1' and 'n2' of the materials and incident light angles 'θ1' formed by the tubing surface
Implementation Method 3
whereas light transmitted through turbid media (e.g., blood or a blood component) will be dispersed, rather than exiting along a single path that can be fully received by a single photodiode
Data Source
AI summary
An optical detection assembly for monitoring a fluid includes a light source, a light detector array, and a controller. The light source emits light into a fluid, while the light detector array includes a plurality of light detectors and receives light exiting the fluid. The controller determines the concentration of one or more substances in the fluid based on signals received from the light detector array. The assembly may include a second light detector array, with one array receiving transmitted light exiting the fluid, with the other receiving scattered light exiting the fluid. The assembly may include a vessel attachment receiving a portion of a vessel or a vessel connector connecting two vessels. The controller may be configured to determine the concentration of one or more substances in a fluid within a vessel received by a vessel attachment or in a fluid within a conduit defined by a vessel connector.