Thin Film Plasmonic Emitter for Low Power NDIR Gas Sensors
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Solution Overview
Problem
Conventional non-dispersive infrared (NDIR) gas sensors with blackbody emitters suffer from high power consumption, heat management issues, and fragility due to broadband emission and the need for precision optics, limiting their application in compact and hazardous environments.
Innovation Solution
A thin film plasmonic emitter with a small thermal mass, capable of producing narrow-bandwidth, time-modulated infrared radiation, eliminating the need for focusing optics and enabling self-calibration, thus reducing power consumption and enhancing mechanical durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional blackbody emitters are used in NDIR gas sensors, then broadband infrared radiation is emitted for gas detection, but power consumption increases significantly and heat management becomes complex
Solution Approach 1:
The patent applies local quality by using a thin film emitter with selective spectral emission characteristics tailored to specific gas absorption wavelengths, rather than broadband blackbody radiation. This localized spectral quality matches the absorption bands of target gases, reducing wasted energy across the entire infrared spectrum and lowering power consumption while maintaining detection reliability.
Solution Approach 2:
The patent changes the emitter parameters from conventional blackbody characteristics to thin film plasma resonance characteristics, enabling narrowband emission at specific wavelengths. This parameter change allows the emitter to operate at lower temperatures with reduced power consumption while providing the necessary infrared radiation for gas detection.
2Measurement precision
If narrow band-pass filters are used to block out-of-band radiation from blackbody emitters, then radiation reaching the photodetector is improved, but greater than 90% of the radiation is converted into wasted heat
Solution Approach 1:
The patent applies preliminary action by pre-filtering the infrared radiation at the emitter level through thin film plasma resonance structures, so that only the desired narrow wavelength band is emitted toward the gas cell. This eliminates the need for subsequent narrow band-pass filters and prevents the energy waste that would occur if most radiation were blocked after emission.
Solution Approach 2:
The patent extracts only the necessary wavelength components from the infrared spectrum at the emitter level, removing unwanted out-of-band radiation before it reaches the gas cell and photodetector. This extraction approach avoids the energy waste inherent in using narrow band-pass filters that block most radiation after full-spectrum emission.
3Measurement precision
If precision focusing and collimating optics are incorporated to use emitted radiation efficiently, then detection sensitivity is improved, but manufacturing costs increase and device fragility increases
Solution Approach 1:
The patent applies self-service by designing the thin film emitter to inherently produce a collimated beam of infrared radiation through its plasma resonance characteristics and geometric configuration. This self-collimating property eliminates the need for external focusing and collimating optics, reducing manufacturing complexity and cost while maintaining detection sensitivity.
Solution Approach 2:
The patent replaces the mechanical optical system (focusing and collimating lenses, mirrors) with an electromagnetic field-based solution embedded in the thin film emitter structure. The plasma resonance characteristics and geometric design of the emitter directly produce the desired collimated radiation pattern, substituting complex mechanical optics with an integrated electromagnetic field approach.
4Illumination intensity
If conventional blackbody emitters are used, then sufficient infrared radiation is emitted for gas detection, but the gas sensor module requires sophisticated heat management schemes to prevent hotspots
Solution Approach 1:
The patent changes the emitter parameters from blackbody radiation characteristics to thin film plasma resonance characteristics, enabling efficient infrared emission at lower operating temperatures. This parameter change allows sufficient radiation intensity for gas detection without generating the excessive heat that would require sophisticated thermal management systems.
Solution Approach 2:
The patent applies local quality by confining the thermal energy generation to the thin film emitter layer with high thermal selectivity, rather than heating a large blackbody surface. The thin film structure with its small thermal mass and selective emission properties localizes the energy conversion, preventing heat diffusion and hotspot formation in the surrounding module components.
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 solution results in compact, low-power gas sensors that are intrinsically safe for hazardous environments, capable of accurate and efficient gas detection with improved sensitivity and selectivity, and reduced manufacturing costs.
Implementation Method 1
thin film plasmonic emitter with a small thermal mass, capable of producing narrow-bandwidth, time-modulated infrared radiation
Implementation Method 2
When optical radiation from an infrared emitter is absorbed by the gas molecule at its characteristic wavelength, the measured value of optical radiation at that specific wavelength is reduced
Implementation Method 3
a photodetector for measuring intensity of light that passes through the gas cell
Data Source
AI summary
Systems and methods herein provide low power non-dispersive infrared (NDIR) gas sensors. The gas sensors comprise a thin film plasmonic light source that produces a time modulated parallel light beam at multiple selected wavelengths. The parallel light beam from the light source passes through a gas chamber without using focusing or collimating optical components. The gas sensors are continuously self-calibrated against environmental changes, such as temperatures and relative humidity, and aging. The gas sensors are suitable for use in hazardous environments because their low power and small thermal mass reduces the risk of explosion. The gas sensors can be integrated into conventional mobile device platforms.