Beam-Guiding Cavity Structure for Compact NDIR Gas Sensors
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Solution Overview
Problem
Conventional non-dispersive infrared (NDIR) gas sensors face challenges in increasing the light path length while maintaining a compact design, leading to poor signal-to-noise ratios due to optical losses and increased dimensions.
Innovation Solution
A beam-guiding cavity structure with curved surfaces having focal points is used, allowing for an extended optical length without increasing spatial extent, reducing reflections and power loss, and enabling a compact gas sensor design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light path length is increased to achieve meaningful absorption, then the measurement precision is improved, but the device dimensions increase and optical losses increase leading to poor signal-to-noise ratio
Solution Approach 1:
The patent employs curved reflective surfaces (ellipsoidal or parabolic) instead of flat surfaces to guide electromagnetic radiation. These curved surfaces enable the radiation to traverse a longer optical path length within a compact spatial footprint, resolving the contradiction between measurement precision and device dimensions.
Solution Approach 2:
The invention transforms the light path from a straight linear trajectory to a curved multi-dimensional path using reflective surfaces. This allows the optical path to fold back on itself, increasing the effective path length without proportionally increasing the device's external dimensions.
2Measurement precision
If the light path length is increased to achieve meaningful absorption, then the measurement precision is improved, but optical losses increase leading to poor signal-to-noise ratio
Solution Approach 1:
The curved reflective surfaces are designed with specific geometries (ellipsoidal or parabolic) that optimize the reflection of electromagnetic radiation. These shapes ensure that radiation follows a controlled path with minimal scattering and absorption losses at each reflection, maintaining signal strength despite the extended path length.
Solution Approach 2:
The patent optimizes parameters such as the curvature radius, focal points, and reflective surface angles to minimize optical losses. By carefully tuning these geometric parameters, the system achieves long light paths while maintaining high signal-to-noise ratios through reduced energy loss at each reflection point.
3Volume of moving object
If curved surfaces with focal points are used to extend optical length, then the compactness is improved, but the device complexity increases
Solution Approach 1:
The patent uses standard geometric shapes (ellipsoidal or parabolic surfaces) that, while curved, can be manufactured using conventional techniques. The complexity is managed by selecting from well-established geometric forms rather than arbitrary curved surfaces, balancing compactness with manufacturability.
Solution Approach 2:
The curved reflective surfaces serve multiple functions simultaneously: they extend the optical path length, guide the electromagnetic radiation, and define the cavity geometry. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in overall device complexity despite the curved surface design.
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 enhances the compactness of gas sensors, reduces energy consumption, and improves detection limits by minimizing reflections and maintaining a high signal-to-noise ratio.
Implementation Method 1
The beam-guiding cavity structure is configured, for example in respect of the shape and reflectivity of the curved surface(s), in such a way that (a substantial proportion or substantially all of the) electromagnetic radiation from the second focal point impinges on the first focal point after (precisely one) reflection at the curved surface
Implementation Method 2
for example by the curved surface having an ellipsoidal shape
Data Source
AI summary
In an embodiment a beam-guiding cavity structure includes at least one first curved surface, one second curved surface and one third curved surface spanning a cavity, the first-third curved surfaces respectively having at least one first focal point and one second focal point, wherein the cavity is configured such that substantially no distance is laterally formed between the first focal point of the first curved surface and the second focal point of the second curved surface, wherein the cavity is further configured such that substantially no distance is laterally formed between the first focal point of the second curved surface and the second focal point of the third curved surface, wherein the first focal point of the second curved surface is arranged next to a connecting line of the first and second focal points of the first curved surface, wherein the first focal point of the third curved surface is arranged next to a connecting line of the first and second focal points of the second curved surface, and wherein the first, second and third curved surfaces have different shapes or dimensions to one another.