Variable Angle Reflective Surface for Optical Sensor Misalignment
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Solution Overview
Problem
Current optical sensors for detecting pathogens in food and environmental samples face challenges such as low sensitivity, misalignment errors, and inefficiencies in light delivery and recovery, particularly in handling large sample volumes and heterogeneous samples like raw foodstuffs, which affect the accuracy and reliability of pathogen detection.
Innovation Solution
An optical sensor design featuring a variable reflected propagation angle reflective surface and a radially segmented bifocal lens system that enhances light delivery and recovery, minimizing misalignment errors and optimizing the evanescent electric field strength, even in the presence of lateral, axial, and angular misalignments, to improve sensitivity and accuracy across a range of sample conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional optical sensor is used, then the structure is simple, but misalignment errors significantly degrade light delivery and signal recovery
Solution Approach 1:
The patent employs dynamically adjustable optical elements including a variable focus lens and a reflective surface with variable propagation angle that can be adjusted in real-time to compensate for misalignment errors. This dynamic adjustment capability allows the system to maintain optimal performance despite lateral, axial, or angular misalignments between the sensor and light source
Solution Approach 2:
The system changes optical parameters such as focal length, reflection angle, and beam divergence to optimize light delivery and recovery. By varying these parameters in response to detected misalignment conditions, the system compensates for positioning errors and maintains reliable sensing performance
2Measurement precision
If the evanescent wave region size is reduced to improve specificity, then the detection specificity increases, but the sensitivity decreases
Solution Approach 1:
The system employs periodic modulation of the light source and synchronized detection to enhance signal specificity. By using time-resolved detection and periodic excitation, the system can distinguish specific analyte-binding events from non-specific background signals, improving measurement precision without sacrificing sensitivity
Solution Approach 2:
The system incorporates feedback mechanisms where the detected signal is continuously monitored and used to adjust excitation parameters. This feedback loop allows optimization of the evanescent field interaction conditions to maintain high sensitivity while ensuring that only specific binding events are detected through pattern recognition and signal validation
3Measurement precision
If the sensor is designed for high sensitivity to detect low concentration pathogens, then the detection limit decreases, but the device complexity increases
Solution Approach 1:
The optical system is segmented into distinct functional modules: a light source module, a sensor module with waveguide, and a detection module. This segmentation allows each component to be optimized independently for sensitivity while managing overall system complexity. The modular design facilitates easier alignment and maintenance
Solution Approach 2:
The patent introduces intermediary optical elements such as lens systems and reflective surfaces that mediate between the light source and the evanescent wave generation region. These intermediaries enhance light coupling efficiency and evanescent field strength, enabling high sensitivity detection without requiring excessively complex direct coupling mechanisms
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 solution significantly enhances the sensitivity and reliability of pathogen detection by maximizing the amount of excitation light delivered and signal recovery light collected, maintaining high evanescent electric field strength despite misalignment errors, thus improving the overall performance of the optical sensor in detecting pathogens in complex samples.
Implementation Method 1
a variable reflected propagation angle θ0i reflective surface 227 that is selected to maximize the amount of the excitation light 30 that it reflects into the sensing waveguide 228
Implementation Method 2
An electromagnetic wave, traveling through one material, that is reflected at a dielectric interface produces an exponentially decaying electric field within the second material on the opposite side of the interface. At optical frequencies this is termed the evanescent wave effect
Implementation Method 3
The evanescent field produced by light 108 passing through the fiber 102 then excites the fluorophores into light emission 110
Data Source
AI summary
A misalignment compensating optical sensor (222), that is operable to receive excitation light (30) having a range of input propagation angles ω. The sensor (222) has a variable reflected propagation angle θ0i reflective surface (227) and a sensing waveguide (228). The shape of the reflective surface (227) is selected to maximize the amount of the excitation light (30) it reflects into the sensing waveguide (227) despite misalignment errors between the sensor (222) and the source (58) of excitation light (30). The sensor may also have a lens portion (160) for focusing the excitation light (30) onto the reflective surface (227), and/or a lens portion (174) for collimating the output of signal recovery light (32) from the waveguide (228). An iterative method may be used for designing any particular lens portion (160, 174).