Optical Sensor Arrangement for Chemical Reaction Measurement
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Solution Overview
Problem
Current measuring arrangements for chemical reactions suffer from low signal-to-noise ratio (SNR) and high detection thresholds due to the splitting of optical signals among multiple photodetectors, leading to reduced resolution and increased noise from adjacent photodetectors not originally assigned to the relevant test section.
Innovation Solution
A measuring arrangement with a sample carrier and photosensitive sensor where the distance between test sections and photodetectors is less than 700 μm, featuring a thin transparent cover layer over photodetectors to protect them from sample material and a microfluidic system that allows for precise alignment, ensuring that most light falls on individual photodetectors, thereby enhancing SNR and reducing dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a photodiode array with multiple photodetectors (5-7 photodetectors per test section) is used to capture the test section, then the test section can be captured by multiple photodetectors, but the electromagnetic radiation incident on each individual photodetector is reduced and the signal is split between several photodetectors, resulting in a very low signal-to-noise ratio
Solution Approach 1:
The patent applies segmentation by using a large number of photodetectors (e.g., 1024 photodetectors in a linear array or 2048 in a 2D array) to capture the optical signal from test sections. Each photodetector is assigned to a specific test section, allowing the optical signal to be concentrated on individual photodetectors rather than split among few photodetectors. This segmentation approach maintains high light intensity per photodetector while achieving precise spatial resolution and high signal-to-noise ratio.
2Measurement precision
If the optical detector is placed at a greater distance from the test section, then the detection system is easier to implement, but the signal intensity decreases and the detection threshold increases
Solution Approach 1:
The patent introduces an intermediary optical system comprising lenses or lens arrays positioned between the test sections and the photodetector array. This optical intermediary focuses and directs the optical signal from each test section onto its corresponding photodetector, maintaining high signal intensity even when the detector is positioned at a practical distance from the test section. The optical intermediary enables both adequate working distance and high detection sensitivity.
3Measurement precision
If photodetectors are arranged in a array to capture multiple test sections, then spatial resolution can be achieved, but noise from adjacent photodetectors not originally assigned to the relevant test section increases
Solution Approach 1:
The patent uses a dense photodetector array where each photodetector is specifically assigned to monitor a particular test section. This segmentation ensures that the optical signal from each test section is captured by its dedicated photodetector, minimizing cross-talk and noise from adjacent photodetectors. The high spatial resolution is achieved through the dense packing of photodetectors, each with a small active area that corresponds to its assigned test section.
Solution Approach 2:
The patent applies local quality by ensuring that each photodetector has optimized characteristics for its specific position and assigned test section. The photodetector array is configured such that each element has the appropriate sensitivity and spatial characteristics for its local measurement task, reducing interference from adjacent areas and improving the signal-to-noise ratio for each specific test section.
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 achieves a higher signal-to-noise ratio and lower detection threshold, allowing for more accurate and sensitive chemical reaction measurements by concentrating light intensity on specific photodetectors and minimizing noise from adjacent areas.
Implementation Method 1
a photodetector (6) arranged opposite the test section (9) for detecting brightness incident from the test section (9)
Data Source
AI summary
The invention relates to a measuring arrangement for optically evaluating a chemical reaction quantitatively, comprising a sample carrier having a carrier layer and a sample layer having an analysis side and a light outlet side opposite the analysis side, and comprising a photosensitive sensor having a plurality of photodetectors on a carrying body and having a transparent surface layer arranged over the photodetectors. A plurality of test sections are arranged on the analysis side at a distance from each other in a longitudinal direction of the sample layer. The analysis side is arranged on the carrier layer in such a way that the test sections face a volume of a microfluidic system. The sample carrier is detachably arranged in an accommodating device, so that the light outlet side faces the photosensitive sensor and the test sections are arranged over the photodetectors. Furthermore, the distance between the test sections and the photodetectors is less than 700 μm.