Luminous Unit Angular Alignment for Optical Gas Detector
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Solution Overview
Problem
Existing gas detection systems using linearly polarized light radiation suffer from interference effects at the exit window, leading to fluctuations in light intensity and a compromised signal-to-noise ratio, particularly in open path gas detection, making it difficult to distinguish between gas absorption and interference-induced attenuation.
Innovation Solution
A luminous unit with a tunable wavelength is designed, where the light source is aligned such that the main emission direction forms an inclination angle of 10° to 50° with the exit window's normal and the polarization direction encloses a rotation angle of 22.5° to 67.5° with the plane of incidence, minimizing interference effects and reducing wavelength dependency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the exit window is tilted at the Brewster angle (57°) to reduce back-reflections, then the intensity stability is improved, but interference effects still occur at the exit window causing fluctuations in light intensity
Solution Approach 1:
The patent changes the inclination angle parameter from the conventional Brewster angle (57°) to a new range of 10°-50°, and simultaneously adjusts the polarization direction angle from 0° to 22.5°-67.5°. This parameter optimization eliminates interference effects while maintaining intensity stability, as verified by the transmission characteristics shown in the patent figures.
2Device complexity
If the light source is aligned perpendicular to the exit window, then the optical path is simplified, but disruptive optical modulations occur due to interference effects
Solution Approach 1:
The patent optimizes the inclination angle parameter to 10°-50° and the polarization angle to 22.5°-67.5°, transforming the optical path configuration from perpendicular alignment to an optimized angled configuration. This change eliminates interference-induced optical modulations while maintaining system simplicity.
3Adaptability or versatility
If the wavelength of light is varied for gas detection, then the spectral analysis capability is improved, but wavelength-dependent intensity variations due to interference effects compromise the signal-to-noise ratio
Solution Approach 1:
The patent optimizes the inclination angle (10°-50°) and polarization angle (22.5°-67.5°) parameters to eliminate wavelength-dependent interference effects. This allows full utilization of wavelength tuning capability for spectral analysis without the compromising intensity fluctuations, thereby improving signal-to-noise ratio across the entire tuning range.
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 alignment significantly reduces wavelength-dependent intensity variations, enhancing the stability and accuracy of gas detection by minimizing interference, allowing for better differentiation between gas absorption and interference effects, and simplifying manufacturing by providing four equally valid configurations.
Implementation Method 1
a light source for linearly polarised light radiation
Implementation Method 2
interference effects occur at the exit window which interfere with the signal that is to be measured
Implementation Method 3
the main emission direction (OA) of the light source encloses an inclination angle (φ) of between 10° and 50° with a normal (N) to the main extension plane (HE) of the exit window
Implementation Method 4
tilt the exit window relative to the optical axis or main direction of radiation by the Brewster angle (in this case about 57°). Such a tilt, in linearly polarised laser light in pure p-polarisation, can reduce unwanted back-reflections at the cover
Data Source
AI summary
A luminous unit for an optical gas detector, an optical gas detector including the luminous unit, and a method of recording an absorption spectrum in an optical gas detector include a light source for linearly polarised light radiation and a housing with an exit window. A wavelength of the light radiation radiated from the light source is tunable. The light source is arranged in the housing such that the main emission direction (OA) of the light source encloses an inclination angle (φ) of between 10° and 50° with a normal (N) to the main extension plane (HE) of the exit window. The direction of polarisation (P) of the light radiation encloses a rotation angle (θ) of between 22.5° and 67.5° with the plane of incidence on the exit window.