Raman Probe Stray Light Noise Reduction via Laser-Disabled Background Subtraction

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Solution Overview

Problem

Raman spectroscopy in bioprocessing applications is hindered by high sensitivity to stray light noise, which affects the accuracy of molecule monitoring due to ambient light interference.

Innovation Solution

A system and method that involves performing background noise measurements with the laser disabled and Raman signal acquisition measurements with the laser enabled, followed by processing to create a clean Raman spectrum by averaging and subtracting background noise, thereby reducing stray light noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional Raman signal acquisition is performed with laser enabled, then Raman spectrum data is obtained, but stray light noise significantly degrades measurement precision

Engineering Contradiction:
ImproveRaman spectrum accuracyVSAvoidstray light noise
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary background noise measurements by disabling the laser before performing Raman signal acquisition. This preliminary action captures the stray light noise characteristics without laser interference, allowing subsequent subtraction to improve measurement precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system extracts and separates the stray light noise component from the total signal by performing background measurements with the laser disabled. This extracted noise spectrum is then subtracted from the Raman spectrum to isolate the pure Raman signal, effectively removing the harmful stray light noise.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If background noise measurements are performed with laser disabled, then stray light noise is reduced, but additional measurement time is required

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidmeasurement cycle time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system implements periodic background noise measurements at defined intervals during Raman analysis. This periodic approach balances the need for noise reduction with time efficiency, performing background measurements when most beneficial rather than continuously or only once.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system performs a limited number of background noise measurements (e.g., one or a few) rather than continuous measurements, achieving sufficient noise reduction while minimizing time loss. This partial action approach provides adequate signal-to-noise improvement without excessive time investment.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If multiple background noise measurements are averaged, then noise reduction is improved, but processing complexity increases

Engineering Contradiction:
Improvebackground noise reductionVSAvoiddata processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs averaging of multiple background noise measurements in advance, before the final Raman spectrum is generated. This preliminary averaging simplifies subsequent processing by providing a single averaged background spectrum to subtract, reducing overall processing complexity while maintaining noise reduction benefits.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4411349A1Reduction of stray light noise in optical raman probe sensors
Publication Date: 2024.08.07 MERCK PATENT GMBH
  • EP4411349A1 patent drawingFigure 1
  • EP4411349A1 patent drawingFigure 2
  • EP4411349A1 patent drawingFigure 3

AI summary

A system and method for quantifying the stray light that enters a Raman optical sensor and removes this from the Raman spectrum is disclosed. One or more background noise measurements are performed by the Raman analyzer wherein the laser is disabled during these background noise measurements. One or more traditional signal acquisition measurements are then performed. The results from the background noise measurements and the traditional signal acquisition measurement are then processed. This results in a clean spectrum, where the background noise has been significantly reduced. In some embodiments, background noise measurements are performed before and after the traditional signal acquisition measurement and these noise measurements are averaged.