Fluorescence Detector Aperture Adjustment for Linearity
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Solution Overview
Problem
Conventional fluorescence detectors experience degraded linearity between specimen concentration and fluorescence intensity at high concentrations, leading to inaccurate measurements due to absorption and attenuation of excitation light, resulting in a limited dynamic range.
Innovation Solution
A fluorescence detector with a light beam restriction mechanism and condensing means that allows selection of aperture length, blocking less intense fluorescence further away from the excitation light incidence point, improving linearity and accuracy by focusing more intense fluorescence through a shorter aperture for high concentrations and using a longer aperture for low concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional fluorescence detector uses a flow cell to measure specimen solutions, then it can detect fluorescence intensity, but the linearity between specimen concentration and fluorescence intensity degrades at high concentrations due to excitation light absorption and attenuation
Solution Approach 1:
The invention divides the fluorescence detection into multiple measurement regions along the flow cell length. By using multiple photodetectors positioned at different locations, the system segments the single measurement into multiple partial measurements, each capturing fluorescence from a specific region where excitation light attenuation is minimized.
Solution Approach 2:
The invention transitions from a single-point measurement to a multi-point spatial measurement along the flow cell. By arranging photodetectors at different positions (different spatial dimensions) and combining their signals, the system captures fluorescence intensity distribution across the flow cell length, compensating for excitation light attenuation effects.
2Quantity of substance
If the specimen concentration increases, then the fluorescence signal intensity increases, but the relationship between concentration and intensity becomes non-linear due to increased light absorption
Solution Approach 1:
The invention segments the fluorescence measurement along the flow cell length by positioning multiple photodetectors at different locations. Each detector measures fluorescence from a specific segment, and the combined signal maintains linearity across a wider concentration range by compensating for excitation light attenuation that increases with specimen concentration.
Solution Approach 2:
The invention changes the measurement parameter from a single fluorescence intensity value to a distributed fluorescence intensity profile across multiple positions. By analyzing the spatial distribution of fluorescence signals and combining them appropriately, the system extends the linear measurement range to higher specimen concentrations.
3Productivity
If a single photodetector is used to detect fluorescence, then the device complexity is low, but the dynamic range of measurements is limited due to saturation at high concentrations
Solution Approach 1:
The invention uses multiple photodetectors positioned at different locations along the flow cell to segment the fluorescence detection. This segmentation allows the system to measure a wider dynamic range by capturing fluorescence signals from regions with different excitation light intensities, preventing saturation at high concentrations while maintaining acceptable device complexity.
Solution Approach 2:
The invention makes the fluorescence detection system multi-functional by enabling it to accurately measure both low and high concentration specimens. The multi-detector configuration provides universal measurement capability across an extended dynamic range, allowing a single system to handle diverse specimen concentrations without requiring separate measurement modes or equipment.
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 configuration enhances the linearity of fluorescence intensity with specimen concentration, increasing the measurable range and accuracy, especially at high concentrations, while maintaining sensitivity through efficient fluorescence usage.
Implementation Method 1
a light source unit 1. The excitation side spectrometer 2 extracts light with a specific wavelength from the light that is emitted by a light source unit 1
Implementation Method 2
as the excitation light Lex that is incident on the flow cell 3 passes through the specimen solution S, it is absorbed and attenuated by the specimen solution S
Implementation Method 3
The target component in the specimen solution is excited by the excitation light Lex and emits fluorescence Lm
Implementation Method 4
the wavelength of the fluorescence is dispersed, and the fluorescence is introduced to a photodetector where the fluorescence is detected
Data Source
AI summary
A fluorescence detector is provided to improve the non-linearity relationship between concentration and fluorescence intensity for a high specimen concentration. The detector improves the dynamic range of the measurements. For a high concentration of the specimen, a light beam restriction unit is used so that only the fluorescence being emitted from a region close to the incident end of the excitation light is condensed by the condensing lens and led to the fluorescence side spectrometer and detected. Because the fluorescence emitted from a region after the passage of the excitation light through a specimen solution as well as its strong absorption by the specimen solution is not reflected in the measurement result, the linearity of the relationship between concentration and fluorescence intensity is improved despite the reduction in the fluorescence quantity. For a low specimen concentration, the light beam restriction unit is used to improve sensitivity.