Fluorescence Polarization Measurement Device Spatial Modulation
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Solution Overview
Problem
Existing fluorescence measurement devices face challenges in obtaining a sufficient signal-to-noise ratio (SN ratio) for low fluorescence intensity measurements, which hinders accurate degree of polarization determination in fluorescence polarization immunoassays.
Innovation Solution
A fluorescence polarization measurement device that includes a light source unit emitting linearly polarized excitation light, a polarization direction modulation element that spatially modulates the polarization direction of the excitation light, a detector that captures the spatial distribution of fluorescence intensity, and a controller that extracts specific frequency components to calculate the degree of polarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temporal modulation of polarization plane is used to suppress polarization characteristics influence, then the influence of detector and filter polarization characteristics is suppressed, but the signal-to-noise ratio deteriorates when fluorescence intensity is low
Solution Approach 1:
The patent transitions from temporal modulation (rotating polarization plane over time) to spatial modulation (varying polarization direction across different spatial positions). The excitation light is modulated such that the polarization direction varies across the illumination area, and the detector captures spatial distribution information. This dimensional shift from time to space allows simultaneous suppression of polarization characteristics influence and maintenance of signal-to-noise ratio through spatial frequency analysis.
Solution Approach 2:
The patent employs periodic spatial modulation of the polarization direction across the illumination area. The polarization direction varies periodically in space, creating a spatial frequency pattern that can be detected and analyzed. This periodic spatial variation enables the system to encode polarization information that can be extracted through spatial frequency analysis, resolving the contradiction between suppressing polarization characteristics and maintaining signal quality.
2Measurement precision
If spatial distribution detection is implemented to extract frequency components, then the signal-to-noise ratio is enhanced, but the device complexity increases
Solution Approach 1:
The patent makes the detector multi-functional by enabling it to capture spatial distribution information of fluorescence intensity. The same detector used for measuring fluorescence intensity is also utilized to capture spatial patterns, eliminating the need for separate spatial resolution components. This universal use of the detector reduces device complexity while enabling spatial frequency analysis for enhanced signal-to-noise ratio.
Solution Approach 2:
The patent replaces complex mechanical polarization modulation systems with a spatial modulation approach that can be achieved through simpler optical elements. Instead of mechanically rotating polarizers or modulators, the system uses spatially varying polarization patterns that can be generated through optical interference or anisotropic materials, reducing mechanical complexity while achieving the same measurement objectives.
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
The device enhances the signal-to-noise ratio by extracting frequency components corresponding to the modulation frequency, allowing for accurate determination of the degree of polarization even at low fluorescence intensities, thereby improving measurement sensitivity and accuracy.
Implementation Method 1
a polarization direction modulation element that spatially modulates a polarization direction of the excitation light by a predetermined frequency
Implementation Method 2
fluorescence emitted from the measurement target solution due to the excitation light for which the polarization direction is spatially modulated
Implementation Method 3
a detector that detects a spatial distribution of fluorescence intensity of the fluorescence having a polarization direction in a predetermined direction
Data Source
AI summary
A fluorescence polarization measurement device includes a light source unit, a polarization direction modulation element, a detector, and a controller. The polarization direction modulation element spatially modulates a polarization direction of the excitation light by a predetermined frequency, and emits, on a measurement target solution, the excitation light for which the polarization direction is spatially modulated by the predetermined frequency. The detector detects a spatial distribution of fluorescence intensity of the fluorescence having a polarization direction in a predetermined direction from among fluorescence emitted from the measurement target solution due to the excitation light. The controller extracts, from the detected spatial distribution of fluorescence intensity, a direct current component and a component having a frequency identical to the predetermined frequency, and calculates, based on the extracted component and the direct current component, a degree of polarization of the measurement target solution.