Ring-Oscillator Fluorescence Detection Circuit
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Solution Overview
Problem
Classical time-resolved fluorescence detection systems face challenges in sensitivity due to the need for fast electronic circuits and high gain settings, which can lead to saturation and recovery delays, especially with fluorescent labels having short decay times, limiting the use of larger PIN photodiodes and requiring complex gain adjustments.
Innovation Solution
The system detects accumulated phase shifts in the form of ring-oscillator frequency, eliminating the need for fast gain adjustments and allowing the use of larger PINs, integrating phase shifts to frequency for natural signal gain and noise reduction, thus enhancing sensitivity without sample/hold circuits and averaging filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fast gain adjustments are used in classical time-resolved fluorescence detection, then sensitivity is improved, but saturation and recovery delays occur with short decay time fluorescent labels
Solution Approach 1:
The patent replaces the mechanical/electronic gain adjustment system with a phase-shift integration system. Instead of using fast gain adjustments that cause saturation, the system integrates phase shifts of the fluorescent signal over time to produce a frequency output that is proportional to the fluorescent intensity, eliminating the saturation problem while maintaining sensitivity.
Solution Approach 2:
The patent changes the detection parameter from direct intensity measurement with gain adjustment to phase-shift integration frequency measurement. By measuring the frequency of the integrated phase shifts rather than directly amplifying the fluorescent signal, the system achieves high sensitivity without the saturation and recovery delays associated with fast gain adjustments.
2Measurement precision
If high gain settings are used to detect short decay time fluorescent labels, then detection sensitivity is improved, but circuit recovery delays limit the measurement window
Solution Approach 1:
The patent substitutes the high-gain amplification circuit with a phase-shift integration system that naturally handles short decay times. The integration process accumulates phase information over the fluorescent decay period, allowing sensitive detection of short decay time labels without requiring fast circuit recovery.
Solution Approach 2:
The system performs preliminary phase-shift integration during the fluorescent decay period itself, rather than requiring post-decay amplification. This preliminary integration of phase information captures the full signal energy before decay completes, eliminating the need for recovery delays while maintaining sensitivity.
3Measurement precision
If larger PIN photodiodes are used to increase signal collection, then detection sensitivity is improved, but fast electronic circuits are required which increase system complexity
Solution Approach 1:
The patent replaces the need for fast electronic circuits with a phase-shift integration approach. By integrating the phase shifts in the time domain, the system can use larger PIN photodiodes for better signal collection without requiring complex fast-switching electronics, as the integration process naturally handles the signal timing.
Solution Approach 2:
The patent introduces phase-shift integration as an intermediary process between the photodetector and the final measurement. This intermediary integration step converts the raw fluorescent signal into a frequency output that can be measured without requiring fast electronic circuits, allowing the use of larger, simpler photodiodes.
4Reliability
If sample/hold circuits and averaging filters are used to reduce noise, then measurement stability is improved, but device complexity increases
Solution Approach 1:
The patent merges the noise reduction function into the phase-shift integration process itself. The integration of phase shifts over time naturally averages out random noise while preserving the signal, eliminating the need for separate sample/hold circuits and averaging filters while maintaining measurement stability.
Solution Approach 2:
The phase-shift integration system performs self-service noise reduction through its inherent time-domain integration process. The integration naturally filters high-frequency noise while preserving the lower-frequency signal components, providing measurement stability without requiring additional dedicated noise-reduction circuitry.
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 approach provides sensitive detection with natural signal gain, reduced noise, and the ability to use larger PINs, overcoming the limitations of classical systems by integrating phase shifts to frequency, allowing for more accurate and reliable measurement of fluorescent labels.
Implementation Method 1
a photodetector that detects the light released by a labeling material
Implementation Method 2
The fluorescence material may be excited with a light pulse, and the fluorescence decay may be detected
Data Source
AI summary
The present disclosure relates generally to methods and materials for detecting light released from a labeling material using self triggering excitation. In particular, the present disclosure provides an architecture for a detection system that detects accumulated phase shifts in the form of a ring-oscillator frequency. The present disclosure provides devices for detection of a light released by a labeling material, the device comprising: a start-up circuit that provides power to a pulse generator block that drives an LED driver, a photodetector that detects the light released by a labeling material and provides a first signal; a variable reference that provides a second signal; a slicer for comparing the first signal to the second signal, wherein the slicer generates an output signal with a delay that triggers the pulse generator block after the start-up circuit is disabled; a frequency reference; and a frequency counter for comparing the output from the slicer to the frequency reference thereby producing a output signal.