Optical Gas Detector Spherical Cavity Alignment Tolerance
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Solution Overview
Problem
Existing optical gas detectors with round-trip light beam systems are difficult to manufacture due to precise positioning requirements and are sensitive to misalignments between the transmitter, receiver, and reflector systems.
Innovation Solution
A spherical gas detector design with hemispherical caps assembled into a sphere, where the transmitter-receiver assembly is offset in the equatorial plane, allowing for tolerance in positioning and manufacturing simplicity, and incorporating an imager for additional functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If precise positioning of transmitter and receiver relative to reflector systems is used, then detection accuracy is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs a spherical resonant cavity instead of traditional planar or angular reflector systems. The spherical geometry provides inherent optical path stability where multiple reflections occur along curved paths that are less sensitive to positioning errors. This curvature-based approach maintains detection accuracy while significantly simplifying manufacturing compared to precision-aligned flat mirrors or angular reflectors.
Solution Approach 2:
The transmitter and receiver are pre-positioned at fixed locations on the spherical cavity surface, and the optical paths are pre-established through the spherical geometry. This preliminary configuration eliminates the need for post-assembly alignment adjustments, reducing manufacturing complexity while maintaining detection precision through the inherent stability of the spherical optical paths.
2Measurement precision
If precise positioning of transmitter and receiver relative to reflector systems is used, then detection accuracy is improved, but tolerance to misalignments decreases
Solution Approach 1:
The spherical resonant cavity provides inherent tolerance to misalignments through its curved geometry. When the transmitter or receiver shifts position, the spherical surfaces naturally redirect light rays to maintain stable optical paths, unlike flat or angular reflectors that would cause significant path deviations. This geometric property simultaneously maintains detection accuracy and increases tolerance to positioning errors.
Solution Approach 2:
The patent changes the geometric parameters of the optical system from linear/angular configurations to spherical configurations. This parameter change fundamentally alters the system's sensitivity to misalignments, transforming it from a precision-critical system to one that is inherently tolerant of positioning variations while maintaining detection performance.
3Difficulty of detecting and measuring
If round-trip light beam systems with reflectors are used, then gas detection capability is improved, but manufacturing difficulty increases
Solution Approach 1:
The spherical resonant cavity replaces complex reflector assemblies with a single monolithic spherical structure. This eliminates the need for multiple separate reflector components and their associated alignment requirements, significantly simplifying manufacturing while maintaining the round-trip light beam functionality necessary for sensitive gas detection.
Solution Approach 2:
The patent merges multiple reflector surfaces into a single spherical cavity structure. Instead of requiring separate reflectors positioned at specific angles, the spherical surface provides all necessary reflection surfaces in one integrated component, reducing assembly steps and manufacturing complexity while preserving the multi-reflection optical path for enhanced gas detection capability.
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 is insensitive to misalignment errors, reducing manufacturing complexity and costs while maintaining detection accuracy, and can integrate an imager for enhanced functionality like infrared imaging.
Implementation Method 1
optical detectors which detect the presence of a gas by measuring the absorption of a light beam at one or more wavelengths corresponding to one or more absorption lines of the gas
Implementation Method 2
the light beam propagating between the transmitter and the receiver is often provided to make one or more round trips via reflector systems
Data Source
Figure 1~2B
Figure 2C~3
AI summary
The detector has first and second hemispherical caps (1-1, 1-2) including opposite concavities and a plate arranged in an equatorial plane (5) of the hemispherical caps. The hemispherical caps are reflective on a portion of opposite surfaces. The plate is placed at distance from a center of an equatorial plane. A diverging light generator (AB) is directed toward the first hemispherical cap. A light detector (CD) is directed toward the second hemispherical cap. The hemispherical caps are assembled in a sphere and spaced apart from each other by a ring (3). An independent claim is also included for an imager detector.