Optical Flow Cell With Dynamic Pathlength Switching for Accurate Measurement

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Solution Overview

Problem

Existing optical flow cells face inaccuracies in measurement due to non-linear absorption responses at high or low concentrations, and require multiple optical paths or complex systems, which increase cost and complexity.

Innovation Solution

An optical flow cell with a retractable optical pathlength adjuster and modifier, using a piezo-electric cantilever driver mechanism or magnetic element, allows rapid adjustment of optical pathlength without multiple waveguides, enabling accurate and fast pathlength variation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a fixed optical path length is used, then the device complexity is reduced, but the measurement precision deteriorates at high or low concentrations due to non-linear absorption responses

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements a variable optical path length flow cell where the optical path length can be dynamically adjusted between at least two different lengths. This allows the system to adapt to different concentration ranges, maintaining linear absorption responses and measurement precision across varying conditions, thereby resolving the contradiction between fixed simplicity and variable precision.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If multiple optical paths or waveguides are provided to enable variable pathlength, then the measurement precision improves, but the device complexity and cost increase

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the single optical path into multiple selectable path lengths within the same flow cell structure. By providing at least two distinct optical path lengths through a single cell design, the system achieves variable pathlength capability without requiring multiple separate flow cells or waveguide systems, thus reducing complexity while maintaining measurement precision.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If a moveable optical fibre is used to vary optical pathlength, then the adaptability improves, but the speed of adjustment deteriorates making real-time measurement impossible

Engineering Contradiction:
ImproveadaptabilityVSAvoidadjustment speed
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The patent implements rapid switching capability between different optical path lengths, enabling real-time adaptation to varying concentration conditions. This dynamic switching mechanism allows the system to change path lengths quickly enough for real-time measurements in fast-flowing fluids, resolving the contradiction between adaptability and adjustment speed.

Inventive Principle:
Principle #15Dynamics

4Adaptability or versatility

If an adjustable cell length is used to vary optical pathlength, then the adaptability improves, but the ease of operation deteriorates due to difficulty in achieving high accuracy and repeatability

Engineering Contradiction:
ImproveadaptabilityVSAvoidease of operation
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent provides discrete, predefined optical path length options within a single flow cell, eliminating the need for continuous adjustment mechanisms. This segmented approach allows operators to select from specific path length configurations, ensuring high accuracy and repeatability while maintaining ease of operation through simple selection rather than complex adjustment procedures.

Inventive Principle:
Principle #1Segmentation

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 accurate and fast optical pathlength adjustment, improving measurement range and reducing complexity and cost by eliminating the need for multiple optical paths and waveguides.

Implementation Method 1

using a piezo-electric cantilever driver mechanism

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

or magnetic element

Methodology Applied
Scientific EffectMagnetic effect: Magnetic Field

Implementation Method 3

the amount of light passing though the fluid in a cavity of the optical flow cell adheres to the Beer-Lambert law

Methodology Applied
Scientific EffectBeer-Lambert law absorption: Absorption (EM radiation)

Data Source

PatentEP4165392B1Optical flow cell for bioprocessing
Publication Date: 2025.07.30 CYTIVA SWEDEN AB
  • EP4165392B1 patent drawingFigure 1A~1C
  • EP4165392B1 patent drawingFigure 2
  • EP4165392B1 patent drawingFigure 3A~3B

AI summary

Disclosed is an optical flow cell (100, 300) and a method (400) for bioprocessing applications. The optical flow cell (100, 300) comprises a fluid inlet (102, 302), a fluid outlet (104, 304), and a fluid flow channel (106, 306) provided between said fluid inlet (102, 302) and said fluid outlet (104, 304). The optical flow cell (100, 300) also comprises an output optical waveguide (108, 308) configured to emit light into said fluid flow channel (106, 306), and a collector optical waveguide (110, 310) configured to collect light from said fluid flow channel (106, 306). An optical pathlength adjuster (120, 320) for varying the optical pathlength (130, 330) between said output optical waveguide (108, 308) and said collector optical waveguide (110, 310) is also provided.