Adjustable Multipass Sample Cell for Compact Gas Detection
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Solution Overview
Problem
Existing gas analysis systems face challenges in achieving compactness and efficient gas detection due to the arrangement of sample cells and optical components, which complicates their integration into portable housings.
Innovation Solution
A novel optical cell design featuring first and second reflecting elements with entrance and exit apertures, allowing light to reflect multiple times before exiting, and an adjustment apparatus for modifying the path length by moving or rotating these elements, enabling flexible path length adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional sample cell arrangement is used, then the system can perform gas analysis, but the system size becomes large and difficult to housing within compact portable units
Solution Approach 1:
The patent employs a multi-pass optical path arrangement where light reflects multiple times between two opposing mirrors within a compact cell volume. This transforms a single-pass linear geometry into a multi-dimensional reflected path, effectively increasing the optical path length without proportionally increasing the physical cell volume, thereby enabling compact portable housing while maintaining gas detection capability
Solution Approach 2:
The optical path is nested within the compact cell structure by having light bounce repeatedly between opposing mirrors, effectively folding the optical path into the available space. This nesting allows the optical path length to be much longer than the physical dimensions of the cell, achieving compact size while preserving detection reliability
2Measurement precision
If the optical path length is increased to improve detection precision, then measurement precision improves, but the device complexity and size increase
Solution Approach 1:
By transforming the optical path from a simple linear arrangement to a multi-pass reflected path between opposing mirrors, the patent achieves extended optical path length within a compact footprint. This dimensional transformation allows increased measurement precision through longer interaction path without proportionally increasing device complexity
Solution Approach 2:
The two opposing mirrors serve multiple functions: they define the optical cavity boundaries, provide the reflection surfaces for multi-pass light routing, and enable adjustable path length through their relative positioning. This multi-functionality reduces the number of separate components needed, thereby reducing device complexity while achieving extended optical path for improved precision
3Adaptability or versatility
If the optical path length is fixed to simplify the device, then device complexity reduces, but adaptability to different detection requirements decreases
Solution Approach 1:
The patent implements adjustability by allowing relative movement between the two opposing mirrors through a mounting mechanism. This dynamic configuration enables the optical path length to be adjusted by changing the mirror spacing or angular orientation, providing adaptability to different detection requirements while keeping the adjustment mechanism relatively simple
Solution Approach 2:
The optical path length parameter can be changed by adjusting the physical configuration of the mirror assembly, such as the distance between mirrors or their angular positions. This parameter adjustability provides versatility for different detection applications without requiring a completely different device design, balancing adaptability with manageable complexity
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 design allows for a compact and efficient gas detection system with adjustable path length, enhancing the system's ability to detect multiple gases with high precision and reduced interference.
Implementation Method 1
light introduced into the cell via the entrance aperture is reflected at least once by the second reflecting element and at least once by the first reflecting element before leaving the cell via the exit aperture
Implementation Method 2
gas analysis based on laser absorption spectroscopy
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
An optical cell comprises first and second opposed reflecting elements (80, 82), an entrance aperture (84) in the first reflecting element and an exit aperture (86) in the second reflecting element, wherein the entrance and exit apertures are configured such that, in operation, light introduced into the cell via the entrance aperture is reflected at least once by the second reflecting element and at least once by the first reflecting element before leaving the cell via the exit aperture. The optical cell may further comprise an adjustment apparatus for obtaining relative movement, e. g., translation or rotation, of the first and second reflecting elements to modify the path length of the light within the cell.