Optical Gas Sensor Temperature Drift Mitigation
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Solution Overview
Problem
Conventional non-dispersive infrared (NDIR) gas sensors face challenges in maintaining measurement accuracy due to temperature variations in the substrate, especially when the light source and light receiver are mounted on the same substrate, leading to fluctuations in gas concentration values.
Innovation Solution
The optical gas sensor device employs a light source that emits infrared rays, an optical filter transmitting wavelengths corresponding to gas absorption, and a light receiver generating detection signals. A signal processor intermittently controls the light source's on/off state, calculating gas concentration by subtracting detection values when the light source is off from those when it is on, thereby mitigating the impact of substrate temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the light source and light receiver are mounted on the same substrate, then the device configuration is miniaturized and simplified, but the substrate temperature variations cause large effects on the detection signal and gas concentration measurement accuracy
Solution Approach 1:
The light source is driven to emit infrared light intermittently in a periodic manner, alternating between emission periods and non-emission periods. During emission periods, the light source emits infrared light to detect gas concentration. During non-emission periods, the light source does not emit, allowing the substrate to cool down. This periodic operation enables the system to capture detection signals at different temperature states, and through differential processing, eliminates temperature drift effects while maintaining miniaturized configuration.
Solution Approach 2:
The system changes the operational parameters of the light source by switching between on and off states, creating varying temperature conditions on the substrate. By measuring detection signals under different temperature parameters (when light source is on vs. off), the system can calculate differential values that cancel out temperature-induced drift, thereby maintaining measurement precision in a compact design.
2Productivity
If the light source continuously emits infrared light, then the detection signal is continuously available, but the substrate temperature increases causing variation in gas concentration values
Solution Approach 1:
The light source operates periodically rather than continuously, emitting infrared light for detection during emission periods and remaining off during non-emission periods. This periodic operation prevents continuous heating of the substrate, thereby stabilizing the substrate temperature and ensuring reliable, drift-free gas concentration measurements while maintaining detection capability.
Solution Approach 2:
The system proactively prevents substrate temperature increase by introducing non-emission periods before temperature drift can significantly affect measurement reliability. During these non-emission periods, the substrate is allowed to cool down in advance, cushioning against future temperature-induced measurement variations and ensuring stable operation.
3Adaptability or versatility
If the substrate temperature changes, then the device operates in varying thermal conditions, but the detection signal varies leading to inaccurate gas concentration calculations
Solution Approach 1:
The system deliberately changes the thermal parameter of the substrate by alternating the light source between on and off states. This creates measurable detection signals under different temperature parameters, allowing the system to calculate differential values that eliminate temperature drift effects and maintain accurate gas concentration calculations despite varying thermal conditions.
Solution Approach 2:
The system uses feedback from detection signals obtained at different temperature states (light source on vs. off) to calculate differential values. This feedback mechanism allows the system to compensate for substrate temperature changes and maintain precise gas concentration measurements by continuously adjusting for thermal drift effects.
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 approach stabilizes gas concentration measurements by reducing the effect of substrate temperature variations and shortens the time to achieve accurate readings, improving the reliability and efficiency of gas detection.
Implementation Method 1
a light source that emits an infrared ray to a gas as a detection target
Implementation Method 2
an optical filter that transmits the infrared ray with a wavelength corresponding to an absorption wavelength of the gas as the detection target
Implementation Method 3
a light receiver that generates a detection signal by detecting the infrared ray incident through the optical filter
Data Source
AI summary
An optical gas sensor device includes the following. A light source emits an infrared ray to a gas as a detection target. An optical filter transmits the infrared ray with a wavelength corresponding to an absorption wavelength of the gas as the detection target. A light receiver generates a detection signal by detecting the infrared ray incident through the optical filter. A substrate is provided, and the light source and the light receiver are mounted on the substrate. A signal processor intermittently drives and controls on and off of the light source, and calculates a gas concentration value of the gas as the detection target from a difference value acquired by subtracting a detection value of the detection signal when the light source is off from the detection value of the detection signal when the light source is on.