FTIR Spectrometer Internal Reference Interferograms for Drift Compensation

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Solution Overview

Problem

FTIR instruments require recalibration due to changes in ambient conditions, which increases measurement time and complexity, necessitating skilled operator intervention to eliminate instrument-induced artifacts.

Innovation Solution

Utilizing internal interferograms from interfering beams reflected back towards the beam source or directed outside the instrument to compensate for spectral changes, allowing continuous data acquisition without operator intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual recalibration is performed to eliminate instrument-induced artifacts, then measurement precision is improved, but measurement time increases and operational complexity increases

Engineering Contradiction:
Improvespectral data accuracyVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs self-calibration by automatically acquiring internal reference interferograms and processing them to generate correction spectra. The processor automatically compares reference spectra with sample spectra and applies corrections without requiring manual intervention, thereby maintaining measurement precision while eliminating the need for operator intervention during recalibration

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system continuously monitors instrument performance by acquiring internal reference interferograms and uses the processed reference spectra as feedback to automatically correct sample spectra. This closed-loop feedback mechanism allows the system to compensate for drift and artifacts in real-time without stopping data acquisition

Inventive Principle:
Principle #23Feedback

2Measurement precision

If manual recalibration is performed to eliminate instrument-induced artifacts, then measurement precision is improved, but operational complexity increases

Engineering Contradiction:
Improvespectral data accuracyVSAvoidoperational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system automatically manages its own calibration by acquiring internal reference interferograms, processing them through the Fourier transform, and applying corrections to sample data. This self-service capability eliminates the need for skilled operator intervention and reduces operational complexity while maintaining high measurement precision

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system pre-acquires and stores internal reference interferograms before sample measurement. These reference interferograms are processed in advance to create correction spectra that can be automatically applied to sample data, preparing the system in advance for potential drift or artifacts without requiring manual recalibration during operation

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If recalibration is performed to compensate for instrument changes, then measurement precision is improved, but productivity decreases

Engineering Contradiction:
Improvespectral data accuracyVSAvoiddata acquisition rate
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system continuously acquires internal reference interferograms during the measurement process, allowing uninterrupted data collection. The reference interferograms are processed and applied to correct sample spectra in real-time, maintaining continuous productivity while ensuring measurement precision through ongoing compensation for instrument drift

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system uses continuously acquired reference interferograms as feedback to automatically correct sample spectra during data acquisition. This real-time feedback mechanism allows the system to maintain measurement precision without stopping data collection, thereby preserving productivity

Inventive Principle:
Principle #23Feedback

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

Compensates for instrument-induced artifacts by using internal reference scans, enabling continuous FTIR data acquisition and reducing the need for manual recalibration, thus improving measurement efficiency and reducing operational complexity.

Implementation Method 1

a scannable interferometer... producing interfering beams by varying optical path length differences between the interfering beams

Methodology Applied
Scientific EffectOptical interference: Interference

Implementation Method 2

at least one detector situated to selectively receive interfering sample beams from a sample or interfering internal beams from the scannable interferometer

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP4628858A1Reference method for spectrometer
Publication Date: 2025.10.08 THERMO ELECTRONICS SCI INSTR LLC
  • EP4628858A1 patent drawingFigure 1
  • EP4628858A1 patent drawingFigure 2
  • EP4628858A1 patent drawingFigure 3~4

AI summary

Interfering internal beams can be used to generate an internal reference interferogram. This interferogram can be used to compensate for changes in FTIR instrument performance in response to variable environmental conditions or other instrument variations. Acquisition of such internal interferograms can be done during, after, or prior to acquisition of actual sample data.