Gas Sensor Resonant Cavity Design for Signal Isolation
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Solution Overview
Problem
Existing gas sensors suffer from sensitivity issues and measurement errors due to electrical interference between the infrared transmitter and acoustic sensor, as well as noise interference from external sounds, leading to inaccurate gas concentration detection.
Innovation Solution
A gas sensor design featuring a shell with a receiving cavity divided into two cavities by a flexible film, where the infrared transmitter is in one cavity and the acoustic sensor is in the other, forming a resonant system with an intrinsic frequency matching the modulation frequency of the infrared transmitter, reducing interference and enhancing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the infrared transmitter and acoustic sensor are located in the same cavity, then the device structure is simple, but electrical interference occurs leading to measurement errors and reduced sensitivity
Solution Approach 1:
The receiving cavity is divided into two separate cavities by a partition plate: a first cavity housing the infrared transmitter and a second cavity housing the acoustic sensor. This segmentation physically isolates the two components, eliminating electrical interference while maintaining a compact overall structure.
2Productivity
If external sound signals are present, then the sensor can detect gas, but strong noise interference occurs resulting in inaccurate detection results
Solution Approach 1:
A resonant system is formed using the flexible film, first cavity, and second cavity, with an intrinsic frequency matching the modulation frequency of the infrared transmitter. This resonance amplifies the acoustic signal from gas absorption by 20 dB, significantly improving signal strength and enabling accurate detection while filtering out ambient noise through frequency selectivity.
3Measurement precision
If the resonant system frequency matches the infrared transmitter modulation frequency, then sensitivity is significantly improved with 20 dB signal increase, but the device requires precise frequency matching
Solution Approach 1:
The resonant frequency of the cavity system is designed to match the modulation frequency of the infrared transmitter. By adjusting the volume and dimensions of the first and second cavities, the resonant frequency can be tuned to coincide with the infrared transmitter's operating frequency, achieving maximum sensitivity without requiring complex external frequency control mechanisms.
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 design significantly improves sensitivity by minimizing electrical interference and noise interference, allowing for more accurate gas concentration measurements with enhanced signal strength, specifically increasing sound signal intensity by 20 dB and isolating ambient noise.
Implementation Method 1
the flexible film, the first cavity and the second cavity form a resonant system, an intrinsic frequency of the resonant system is the same as a modulation frequency of the infrared transmitter
Implementation Method 2
This wavelength of the infrared light is strongly absorbed by the gas to be measured and converted into heat. An alternating pressure signal is generated in the internal chamber
Data Source
AI summary
The present disclosure provides a shell with a receiving cavity, an infrared transmitter and an acoustic sensor accommodated in the receiving cavity, and a flexible film connected with the side wall, the shell includes a cover, a substrate, and a side wall, the flexible film divides the receiving cavity into a first cavity and a second cavity, the infrared transmitter is located in the first cavity, the acoustic sensor is located in the second cavity, the shell comprises a vent hole communicating with an outside and the first cavity, the flexible film, the first cavity and the second cavity form a resonant system, an intrinsic frequency of the resonant system is the same as a modulation frequency of the infrared transmitter. Compared with the related art, the gas sensor disclosed by the present disclosure could improve the sensitivity of the product.