Sensor Assembly With Internal Toothed Traps for Stray-Light Reduction
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Solution Overview
Problem
Existing optical sensor arrangements face challenges in effectively reducing stray light interference, leading to reduced signal quality and increased size due to separate housings for light sources and detectors, and existing coatings and light traps have limited effectiveness.
Innovation Solution
A sensor arrangement with a housing featuring a window and toothing on internal chambers to absorb and redirect stray light, using annular teeth oriented to reflect stray light away from detectors and towards the light source or window, with the window offset from the flange center and toothing positioned to minimize reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light source and detection elements are mounted in separate housings, then stray light interference is reduced, but the overall size of the sensor arrangement increases
Solution Approach 1:
The patent combines the light source and detection elements into a single housing, eliminating the need for separate housings and tubes. This merging approach reduces the overall size of the sensor arrangement while implementing internal light trapping structures (toothing) to manage stray light, thus resolving the contradiction between compact size and signal quality.
2Illumination intensity
If anti-reflective coating is applied to the window, then light transmission is improved, but stray light reduction is limited without additional measures
Solution Approach 1:
The patent converts the harmful scattered light into a beneficial effect by using the toothing structure to redirect stray light toward the light source or window, where it can be absorbed or re-reflected. This transforms what would be interference into a control mechanism, effectively reducing stray light while maintaining good light transmission through the window.
3Measurement precision
If toothed scattered light traps are added to filter stray light, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent applies the toothing structure locally at specific positions within the housing where stray light generation is most problematic, rather than making the entire sensor arrangement complex. The toothing is strategically placed to intercept stray light paths while maintaining simplicity in other areas of the device.
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
Significantly reduces stray light intensity, improving signal quality and compactness by absorbing and redirecting stray light, enhancing the ratio of useful signal to background noise.
Implementation Method 1
the intensity of the scattered light reaching the detector from the light source that has not traveled via the sample is reduced by being absorbed by the toothing and/or reflected away from the detector
Implementation Method 2
the toothing is arranged in the area between the light source and the window in such a way that it reflects scattered light in the direction of the light source
Data Source
Figure 1~3
Figure 2
Figure 4~5
AI summary
A sensor arrangement (10) is equipped with a housing (12) having an opening in which a window (18) transparent to electromagnetic waves is mounted, a light source (40) arranged in the housing (12) for generating electromagnetic waves, and a detector (32) arranged in the housing (12) for detecting electromagnetic waves entering through the window (18) that have passed from the light source through the window onto a sample adjacent to the window (18) and have been reflected by the sample. A toothed arrangement (54, 56, 58) is arranged inside the housing (12) which is configured to reduce scattered light reaching the detector (32) from the light source (40).