Swept-Frequency Fluorometry for Overlapping Species Identification

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Solution Overview

Problem

Traditional fluorescence sensing techniques struggle with ambiguous species identification due to overlapping fluorescence signatures, particularly in liquids containing multiple species.

Innovation Solution

A swept frequency fluorometer that utilizes a swept excitation frequency to measure fluorescence lifetime, providing an additional dimension of information for species identification by detecting the phase shift and amplitude changes of fluorescence signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional single-channel fluorometers use fixed frequency lock-in detection, then the detection is simple and reliable, but the species identification becomes ambiguous when fluorescence signatures overlap

Engineering Contradiction:
Improvespecies identification accuracyVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by sweeping the lock-in detection frequency across a range rather than using a fixed frequency. This dynamic frequency sweeping allows the system to capture fluorescence signals at multiple frequencies, enabling discrimination between species with overlapping fluorescence signatures based on their distinct fluorescence lifetimes and phase characteristics.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces another dimension of detection by measuring both amplitude and phase of fluorescence signals across multiple frequencies. This adds temporal dimensionality to the detection, transforming single-frequency amplitude measurement into multi-frequency amplitude-phase measurement, which provides sufficient information to distinguish between overlapping species.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If the excitation light modulation frequency is swept through the characteristic frequency of a species, then the phase shift and amplitude changes provide distinctive identification, but the measurement time increases

Engineering Contradiction:
Improvefluorescence lifetime measurement accuracyVSAvoidmeasurement duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent uses periodic action by sweeping the detection frequency through characteristic frequencies of different species in a systematic manner. The frequency sweeping follows a periodic pattern that allows efficient sampling of the fluorescence response across the frequency spectrum, enabling accurate lifetime measurement without excessive measurement time.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent maintains continuity of useful action by continuously sweeping the detection frequency through the entire range of interest without interruption. This continuous frequency sweeping ensures that no potential identification information is missed and maintains steady measurement progress, optimizing the balance between measurement accuracy and time efficiency.

Inventive Principle:
Principle #20Continuity of useful action

3Adaptability or versatility

If multiple fluorescence species are present in the liquid, then the application scope increases, but the fluorescence signatures overlap and become ambiguous

Engineering Contradiction:
Improvecomplex sample analysis capabilityVSAvoidfluorescence signature discrimination
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent applies segmentation by dividing the frequency spectrum into multiple discrete frequency points for measurement. This segmentation allows the system to separately characterize each species' fluorescence response at different frequencies, creating distinct spectral fingerprints that can be used to discriminate between multiple species even when their overall fluorescence signatures overlap.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes parameter changes by varying the detection frequency as a key parameter to distinguish between species. By changing the frequency parameter across the measurement and analyzing how the fluorescence signal responds at different frequencies, the system extracts distinctive characteristics for each species, enabling accurate identification in complex mixtures.

Inventive Principle:
Principle #35Parameter changes

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

Enhances species identification by distinguishing between overlapping fluorescence species based on their unique fluorescence lifetimes, offering improved detection accuracy.

Implementation Method 1

a light source configured to provide excitation light on a liquid sample having one or more fluorescent species, the excitation light having a variable frequency range

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 2

As the signal's modulation frequency is swept through the characteristic frequency of the species, f = (1/lifetime) [Hz], the phase of the signal undergoes an overall relative phase shift of 90 degrees in addition to a decrease in signal amplitude

Methodology Applied
Scientific EffectPhase shift:

Data Source

PatentEP4153972B1Swept frequency fluorometer
Publication Date: 2026.03.25 YSI INC
  • EP4153972B1 patent drawingFigure 1
  • EP4153972B1 patent drawingFigure 2A~2B
  • EP4153972B1 patent drawingFigure 3

AI summary

A swept frequency fluorometer having a signal processor or processing module configured to: receive signaling containing information about reflected light off one or more fluorescence species-of-interest in a liquid sample that is swept with light having a variable frequency range, the information including a characteristic optical frequency corresponding to a fluorescence species-of-interest in the liquid, and a characteristic/lifetime optical frequency corresponding to a distinct fluorescence lifetime in which the fluorescence species-of-interest remains in an excited state; and provide corresponding signaling containing information about an identity of the fluorescence species-of-interest detected and distinguished from overlapping fluorescence species in the liquid using the characteristic/lifetime optical frequency, based upon the signaling received