Optical Gas Sensor Layout Using Angle-Dependent Spectra
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Solution Overview
Problem
Existing optical physical quantity measuring apparatuses, particularly non-dispersive infrared absorption type gas concentration measuring apparatuses, face challenges in accurately measuring gas concentrations due to fluctuations in light source intensity, optical path reflectance, and detector characteristics, which are not adequately addressed by existing methods using reference signals.
Innovation Solution
The apparatus employs a light-emitting element with a different radiation spectrum depending on the radiation direction, multiple light-receiving elements arranged at different positions, and a reflector to configure optical paths, utilizing wavelength limiting means and absorbers or voids to suppress fluctuations and reduce apparatus size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple optical filters are used to detect different wavelengths, then measurement precision is improved, but device complexity and size increase
Solution Approach 1:
The patent merges multiple wavelength detection functions into a single optical path by using a light-receiving element that simultaneously detects both the first wavelength (gas absorption band) and second wavelength (reference) without requiring separate optical filters for each wavelength, thereby reducing apparatus size while maintaining measurement precision
Solution Approach 2:
The light-receiving element is designed to perform multiple functions: detecting light at the first wavelength for gas concentration measurement and detecting light at the second wavelength for reference signal generation, eliminating the need for separate detection paths and reducing overall device complexity
2Reliability
If a reference signal is used to suppress fluctuations, then reliability is improved, but measurement precision deteriorates due to inability to compensate spectral shape changes
Solution Approach 1:
The patent uses parameter changes by detecting light at two different wavelengths (first and second wavelengths) to capture both gas absorption information and reference information simultaneously, allowing the system to compensate for spectral shape changes caused by temperature and humidity variations while maintaining reliable fluctuation suppression
Solution Approach 2:
The light-receiving element acts as an intermediary that simultaneously captures information from both the absorption band and reference band, enabling the system to use the reference signal for fluctuation suppression while also accounting for spectral shape changes through wavelength-dependent detection
3Productivity
If light-emitting element characteristics fluctuate, then productivity is maintained, but measurement precision deteriorates
Solution Approach 1:
The patent implements feedback by continuously monitoring light intensity at both the first wavelength (affected by gas concentration) and second wavelength (reference) using the same light-receiving element, allowing real-time compensation for light-emitting element characteristic fluctuations while maintaining continuous measurement 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
This configuration enables highly accurate and compact gas concentration measurements by suppressing fluctuations in light-emitting and receiving elements, allowing for simultaneous measurement of different gas concentrations and reducing the size and complexity of the apparatus.
Implementation Method 1
a light-emitting element (L) that has a different radiation spectrum depending on a radiation direction and that emits light at least at a first radiation angle, a second radiation angle, and a third radiation angle
Implementation Method 2
a reflector that causes light emitted from the light-emitting element in different radiation directions to reach a plurality of different positions
Implementation Method 3
a first light-receiving element arranged in an optical path along which the light emitted at the first radiation angle travels, and a second light-receiving element arranged in an optical path along which the light emitted at the second radiation angle travels
Implementation Method 4
an absorber or a void is provided in an optical path along which the light emitted at the third radiation angle travels
Implementation Method 5
a non-dispersive infrared absorption type gas concentration measuring apparatus... based on how gas molecules have a unique absorption band for mid-infrared light
Data Source
AI summary
An optical physical quantity measuring apparatus (1) includes a light-emitting element (L), light-receiving elements (S) including at least a first light-receiving element and a second light-receiving element, and a reflector. The light-emitting element has a different radiation spectrum depending on a radiation direction and emits light at least at a first radiation angle, a second radiation angle, and a third radiation angle into a space in which an object to be measured is located. The reflector causes light emitted from the light-emitting element in different radiation directions to reach different positions. The first light-receiving element is arranged in an optical path formed by light emitted at the first radiation angle. The second light-receiving element is arranged in an optical path formed by light emitted at the second radiation angle. An absorber or a void is provided in an optical path formed by light emitted at the third radiation angle.