Photoacoustic gas sensing device based on polyvinylidene fluoride piezoelectric film

Abstract

The invention discloses an opto-acoustic gas sensing device based on a polyvinylidene fluoride piezoelectric film. The opto-acoustic gas sensing device comprises a light source (1) and a tubular acoustic resonant cavity (6) on an optical path (2) of the light source (1), as well as an opto-acoustic gas sensor arranged at the side opening of the tubular acoustic resonant cavity (6) and a modulation-demodulation component adapting to the opto-acoustic gas sensor, particularly, the tubular acoustic resonant cavity (6) is 20 mm-150 mm in length, and 3 mm-10 mm in internal diameter, the side opening of the tubular acoustic resonant cavity (6) is a small hole (4) communicated with the tubular acoustic resonant cavity (6), the small hole (4) is 1.5 mm-2.5 mm in depth and 1.5 mm-2.5 mm in diameter, the opto-acoustic gas sensor is a polyvinylidene fluoride piezoelectric film (5), the distance between the film plane and the end plane of the small hole (4) is 0.1 mm-3 mm, and the output terminal of the opto-acoustic gas sensor is electrically connected with the input terminal of a phase-locked amplifier (8) of the modulation-demodulation component through a pre-amplifier (6). The opto-acoustic gas sensing device has the characteristics of simple structure, larger response band width and stability in operation, and can be widely used for detecting and determining the strength or chemical compositions of gas.

Description

technical field [0001] The invention relates to a photoacoustic gas sensing device, in particular to a photoacoustic gas sensing device based on polyvinylidene fluoride piezoelectric film. Background technique [0002] Detecting and determining the concentration or chemical composition of gases has a wide range of applications in environmental monitoring, climate, agriculture, security, medical diagnostics, and industry. With the development of laser technology and weak signal detection technology, photoacoustic spectroscopy technology has also been developed rapidly, and photoacoustic spectroscopy technology is considered to be a spectral technology with zero background, high sensitivity and high selectivity. [0003] Photoacoustic spectroscopy is a unique spectroscopic technique that is different from traditional absorption spectroscopy based on the Beer-Lambert absorption law. It is a spectroscopic technique based on the photoacoustic effect. light intensity. When a lig...

AI Technical Summary

Problems solved by technology

Although this gas sensing device using a quartz tuning fork has the characteristics of strong anti-interference ability, because the response bandwidth of the quartz tuning fork is generally less than 5Hz, and the accuracy of the modulation frequency of the laser source is very high, the deviation should be less than 0.1Hz. When the environmental conditions of the detection - temperature, carrier gas composition, etc. change, the modulation frequency of the laser source needs to be corrected in time to ensure accurate signal output.

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