Optoelectronic Detector Evaluation Circuit for Fluorescence Signal Separation
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Solution Overview
Problem
Current evaluation circuits for optoelectronic detectors struggle to distinguish between fluorescent and scattered light, particularly Raman scattered light, which interferes with precise fluorescence measurements and Raman spectrum analysis, due to the inability to effectively separate these signals in real-time without complex spectral filtering.
Innovation Solution
An evaluation circuit with a shift register that stores digital values from an analog-to-digital converter, allowing for time-resolved analysis of fluorescence events by defining time windows and using a marker value to differentiate between fluorescence and scattered light, enabling the suppression of scattered light signals without the need for complex time stamps or statistical analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard spectral filtering is used to separate fluorescence and scattered light, then the measurement of fluorescence is improved, but scattered light such as Raman scattering cannot be eliminated and interferes with precision measurements
Solution Approach 1:
The patent uses periodic light pulses to excite the sample, creating time-dependent fluorescence emission. By synchronizing the detection window with the periodic excitation cycles, the system captures fluorescence signals during specific time intervals while rejecting scattered light that occurs at different times within each cycle.
Solution Approach 2:
The evaluation circuit performs preliminary time-resolved analysis of detected photons by assigning time stamps to each photon based on its detection time relative to the excitation pulse. This preliminary temporal characterization allows subsequent separation of fluorescence and scattered light events without requiring complex spectral filtering during the measurement process.
2Measurement precision
If synchronous evaluation of the detector with light pulses is used, then fluorescence light can be recorded, but no distinction between fluorescence and scattered light is possible
Solution Approach 1:
The patent adds a temporal dimension to the signal evaluation by measuring the time of arrival of each photon relative to the excitation pulse. This time dimension provides an additional parameter for distinguishing between fluorescence and scattered light events, transforming a one-dimensional spectral problem into a two-dimensional temporal-spectral analysis.
Solution Approach 2:
The evaluation circuit performs preliminary time-resolved analysis of detected photons by assigning time stamps to each photon based on its detection time relative to the excitation pulse. This preliminary temporal characterization allows subsequent separation of fluorescence and scattered light events without requiring complex spectral filtering during the measurement process.
3Measurement precision
If complex spectral filtering is used to separate scattered light, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical or optical spectral filtering systems with an electronic time-resolved evaluation circuit. By measuring the time of arrival of each photon and using digital signal processing to separate fluorescence and scattered light based on their temporal characteristics, the system achieves high signal separation accuracy without requiring complex physical filters.
Solution Approach 2:
The evaluation circuit acts as an intermediary between the detector and the final signal analysis, performing time-resolved sorting of photons. This intermediary processing step separates fluorescence and scattered light in the time domain before further analysis, simplifying the overall system architecture compared to implementing complex spectral filtering in the optical path.
4Measurement precision
If time-resolved analysis with timestamps is used to distinguish fluorescence and scattered light, then signal separation is improved, but data processing complexity and time consumption increase
Solution Approach 1:
The patent uses periodic light pulses to excite the sample, creating time-dependent fluorescence emission. By synchronizing the detection window with the periodic excitation cycles, the system captures fluorescence signals during specific time intervals while rejecting scattered light that occurs at different times within each cycle.
Solution Approach 2:
The evaluation circuit performs preliminary time-resolved analysis of detected photons by assigning time stamps to each photon based on its detection time relative to the excitation pulse. This preliminary temporal characterization allows subsequent separation of fluorescence and scattered light events without requiring complex spectral filtering during the measurement process.
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
This solution allows for highly sensitive detection of fluorescence emissions by completely eliminating scattered light, enabling the measurement of low-intensity fluorescence signals that were previously inaccessible and improving the signal-to-noise ratio for precise fluorescence and Raman spectroscopy measurements.
Implementation Method 1
the detector captures light from the sample, converts it into an electrical signal
Implementation Method 2
fluorescence events under excitation by light pulses
Data Source
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AI summary
The invention relates to an evaluation circuit (1) for evaluating the electrical signals (A) of an optoelectronic detector (32) designed for photon detection during the recording of fluorescence events under excitation by light pulses, comprising an analog-to-digital converter (2) or a trigger with an input for connection to an output of the detector (32) and with an output for outputting a digital value (A), and a shift register (3), wherein the evaluation circuit (1) is configured such that light intensities recorded at different times during an illumination cycle are stored independently of one another in the stages of the shift register. The invention further relates to the use of the evaluation circuit (1) for the temporal separation of fluorescence and scattered light from fluorescence events, and to a method for recording fluorescence events.