A quartz tuning fork gas sensing device based on diamond-like carbon coating enhancement

Abstract

The application relates to the field of gas detection, in particular to a quartz tuning fork gas sensing device based on diamond-like coating enhancement, which comprises sequentially connected laser signal emitting units, light absorption cells, lenses, quartz tuning forks and electric signal collecting units, the surface of the quartz tuning fork is coated with a diamond-like coating; target light signals generated by the laser signal emitting units are transmitted to the light absorption cells; the light absorption cells contain target gases to be detected, and light signals interact with the target gases in the light absorption cells; the lenses focus the light emitted from the light absorption cells to the surface of the quartz tuning fork coated with the diamond-like coating. Compared with the prior art, the application can sensitively capture slight changes caused by trace gases, convert the changes into obvious electric signals, and the electric signals have a good linear relationship with the gas concentration, so that low-concentration gases can be measured with high precision.

Description

Technical Field

[0001] This invention relates to the field of free gas detection in transformer gas alarms, and in particular to a quartz tuning fork gas sensing device based on a diamond-like carbon coating. Background Technology

[0002] A gas relay (also known as a gas-powered relay) is a protective device used in transformers. It is installed in the pipeline between the transformer's oil conservator and tank. When an internal transformer fault causes oil decomposition, producing gas, or causes oil flow surge, the gas relay's contacts actuate, connecting a designated control circuit and promptly issuing an alarm signal (light gas) or activating protective components to automatically disconnect the transformer (heavy gas). After a light gas warning or heavy gas disconnection by the gas relay, the free gas inside the relay needs to be analyzed to determine if a transformer fault has occurred and its severity. Precise gas sensing technology facilitates transformer condition monitoring and preventative maintenance. Continuous monitoring of the gas inside the gas relay allows for early detection of potential faults, enabling maintenance to be scheduled before a fault develops into a serious accident, reducing the probability of sudden equipment failures, lowering maintenance costs, extending transformer lifespan, and ensuring the long-term stable operation of the power system.

[0003] For example, Chinese patent application CN118549350A discloses a quartz tuning fork gas detection system based on a perovskite composite material coating. This system utilizes the photothermoelectric effect generated by laser irradiation of the perovskite composite material coating and the photothermoelastic effect of the quartz tuning fork to couple, thereby detecting gases. From a material properties perspective, the organic-inorganic hybrid perovskite component in the perovskite composite material coating is quite sensitive to environmental factors; for example, changes in humidity and temperature can affect its performance. In high-humidity environments, the organic-inorganic hybrid perovskite decomposes, leading to coating structural damage. This, in turn, affects the coupling effect of the photothermoelectric and photothermoelastic effects, making the detection signal unstable and ultimately impacting the accuracy and reliability of the detection.

[0004] The Heriot-Trench gas cell used in perovskite composite coating solutions requires precise temperature control. While the insulation layer helps maintain internal temperature stability to some extent, it is still difficult to ensure that the temperature within the gas cell remains constant within the ideal detection range under extreme temperature conditions. Large temperature fluctuations not only affect the thermoelasticity of gas molecules but may also alter the performance of the perovskite composite coating, reducing detection accuracy. Furthermore, the perovskite composite coating relies on a fitting equation between the second harmonic amplitude and concentration variation to calculate the concentration of the analyte gas. If interference factors exist during actual detection, such as background noise or cross-interference from other gases, the accuracy of the fitting equation may decrease, thus affecting detection precision.

[0005] In summary, perovskite composite coatings are quite sensitive to environmental factors, and their application in complex environments is limited to specific conditions. Furthermore, the detection bands are limited, and the wavelength cannot be flexibly adjusted to achieve multi-band detection. This limits their ability to detect gases with different absorption characteristics and fails to meet complex and diverse detection needs. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology, such as limited detection band and sensitivity to environmental factors and interference during the detection process, and to provide a quartz tuning fork gas sensing device based on diamond-like carbon coating.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A gas sensing device based on a diamond-like carbon coating-enhanced quartz tuning fork includes a laser signal emitting unit, a light absorption cell, a lens, a quartz tuning fork, and an electrical signal acquisition unit connected in sequence, wherein the surface of the quartz tuning fork is coated with a diamond-like carbon coating.

[0009] The target optical signal generated by the laser signal emitting unit is transmitted to the optical absorption cell;

[0010] The optical absorption cell contains the target gas to be detected, and the optical signal interacts with the target gas within the optical absorption cell.

[0011] The lens focuses the light emitted from the light absorption cell onto the surface of a quartz tuning fork coated with a diamond-like carbon layer.

[0012] As a preferred technical solution, the laser signal emitting unit includes a laser, an optical modulator, a power amplifier, a filter, an optical isolator, and a collimator connected in sequence by optical fibers. The optical centers of each unit are on the same horizontal line, and the optical absorption cell is opposite to the collimator.

[0013] As a preferred technical solution, the optical modulator modulates the characteristics of the laser output from the laser to change the energy and variation of the light irradiating the surface of the quartz tuning fork.

[0014] The aforementioned filter selects the wavelength of the light signal so that the light entering the light absorption cell matches the characteristic absorption peak of the target gas.

[0015] As a preferred technical solution, the light absorption cell is provided with an anti-reflection coating, and two reflective mirrors are symmetrically installed on the inner walls of both sides of the light absorption cell, with the center height of the reflective mirrors being consistent with the center axis height of the light absorption cell.

[0016] As a preferred technical solution, the distance between the two reflectors is set between 0.8 and 0.95 times the length of the light absorption cell.

[0017] As a preferred technical solution, the light absorption cell is symmetrically equipped with an air inlet and an exhaust outlet; the target gas to be detected enters the light absorption cell 7 through the air inlet, and the detected gas is discharged from the exhaust outlet.

[0018] As a preferred technical solution, the lens is installed on the side of the light emitting cell, and the center of the lens is on the same horizontal line as the central axis of the light absorption cell.

[0019] As a preferred technical solution, the distance between the lens and the light absorption cell is:

[0020] d = D / (1 + cosθ)

[0021] Where D is the distance from the quartz tuning fork to the exit surface of the light absorption cell; θ is the divergence angle of the light emitted from the light absorption cell.

[0022] As a preferred technical solution, the electrical signal acquisition unit includes sequentially connected data...

[0023] A transimpedance amplifier amplifies the electrical signal generated by a quartz tuning fork.

[0024] A lock-in amplifier selectively amplifies and performs phase-sensitive detection on the signal output from a transimpedance amplifier at a specific frequency, extracting weak signals related to the target gas.

[0025] The computer receives and processes signals from the lock-in amplifier, and analyzes, stores, and displays the gas detection data.

[0026] As a preferred technical solution, the sensing device further includes a laser driver, which is connected to the laser and computer signals to adjust the laser output parameters of the laser according to the detection requirements.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1) This invention utilizes a diamond-like carbon (DLC) coating in a quartz tuning fork gas sensing device. The DLC coating efficiently absorbs modulated light energy, causing the quartz tuning fork to exhibit a significant thermal deposition response to even slight changes in light intensity. This triggers a thermoelastic effect, causing the quartz tuning fork to deform. Due to the piezoelectric effect of the quartz tuning fork itself, this deformation is converted into an electrical signal, realizing the conversion from light energy to mechanical energy and then to electrical energy, thereby detecting gas. It can sensitively capture subtle changes caused by trace gases, converting them into a clear electrical signal, thus achieving gas detection. This invention utilizes the significant thermal deposition response of the DLC coating to slight changes in light intensity to sensitively capture subtle changes caused by trace gases.

[0029] 2) By optimizing the setting of the reflector and lens, the present invention makes the laser signal incident in the light absorption cell and the laser signal acting on the quartz tuning fork on the same horizontal line. By focusing the laser signal, the sensitivity and reliability of gas detection are improved.

[0030] 3) The diamond-like carbon (DLC) coated quartz tuning fork gas sensing device provided by this invention exhibits relatively low sensitivity to environmental factors such as temperature due to its high hardness, wear resistance, and good chemical stability, resulting in stronger environmental adaptability. The DLC coating also effectively protects the quartz tuning fork, reducing the impact of environmental factors such as mechanical vibration and electromagnetic interference, minimizing measurement errors and performance drift, and ensuring stable device operation and accurate signal output.

[0031] 4) The diamond-like carbon coating-enhanced quartz tuning fork gas sensing device provided by this invention has good thermal conductivity, which enables the device to respond quickly and react rapidly to changes in gas concentration. At the same time, by flexibly adjusting parameters such as the wavelength of light, the device can detect various target gases in industrial and environmental monitoring, and has a wide range of applications. Attached Figure Description

[0032] Figure 1 A schematic diagram of a diamond-like carbon coated and reinforced quartz tuning fork gas sensing device provided in an embodiment of the present invention;

[0033] Figure 2 Gas detection curves for existing coating technologies;

[0034] Figure 3 The detection curve of the diamond-coated reinforced quartz tuning fork gas sensor of this application is shown.

[0035] The following are the labels in the diagram: 1. Laser; 2. Optical modulator; 3. Power amplifier; 4. Filter; 5. Optical isolator; 6. Collimator; 7. Optical absorption cell; 8. Mirror; 9. Air inlet; 10. Exhaust outlet; 11. Lens; 12. Quartz tuning fork; 13. Transimpedance amplifier; 14. Lock-in amplifier; 15. Computer; 16. Laser driver. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0037] Example 1

[0038] like Figure 1The diagram shown is a schematic representation of the structure of a diamond-like carbon (DLC) coated and reinforced quartz tuning fork gas sensing device provided in an embodiment of the present invention. The DLC-coated and reinforced quartz tuning fork gas sensing device provided by the present invention includes: a laser 1, an optical modulator 2, a power amplifier 3, a filter 4, an optical isolator 5, a collimator 6, an optical absorption cell 7, a reflector 8, an air inlet 9, an air outlet 10, a lens 11, a quartz tuning fork 12, a transimpedance amplifier 13, a lock-in amplifier 14, a computer 15, and a laser driver 16.

[0039] The positions of the above-mentioned units are set as follows: laser 1, optical modulator 2, power amplifier 3, filter 4, optical isolator 5, and collimator 6 are connected in sequence via optical fiber, and the optical centers of each unit are on the same horizontal line; optical absorption cell 7 is opposite to collimator 6; two mirrors 8 are installed opposite each other in optical absorption cell 7; air inlet 9 and exhaust outlet 10 are symmetrically installed on optical absorption cell 7; lens 11 and quartz tuning fork 12 are installed in sequence on the same optical central axis as optical absorption cell 7; transimpedance amplifier 13, lock-in amplifier 14, and computer 15 are connected in sequence via data lines; computer 15 is also connected to laser driver 16.

[0040] Laser 1 provides initial energy for the thermoelastic effect by emitting intensity-modulated light. It can also achieve precise detection of specific gases by adjusting the wavelength, and control the signal strength by adjusting parameters such as the intensity and modulation frequency of the output light to ensure that a suitable and stable signal can be output for subsequent processing and analysis under different gas concentration environments.

[0041] In this embodiment, laser 1 is preferably an external cavity quantum cascade laser, which has good wavelength tunability, can output high power, and has high accuracy and stability. It can enhance the photothermal elastic effect, realize the detection of multiple gases, and ensure the reliability of the detection.

[0042] The optical modulator 2 precisely controls the intensity, frequency, and other characteristics of the output light from the laser 1, thereby changing the energy and variation of the light irradiating the surface of the quartz tuning fork 12, and thus controlling the degree of thermal deposition caused by the thermoelastic effect and the intensity of the generated electrical signal.

[0043] In this embodiment, the optical modulator 2 is preferably a lithium niobate (LiNbO3) electro-optic modulator, which has the characteristics of high-speed modulation, low insertion loss, wide wavelength range and high extinction ratio, and can accurately and efficiently modulate the intensity, phase and other parameters of the output light of the laser 1.

[0044] Power amplifier 3 amplifies the laser signal modulated by optical modulator 2, providing a sufficiently strong optical signal for subsequent units such as filter 4, optical isolator 5, and collimator 6. This ensures that the optical signal has sufficient energy to drive it throughout the entire process of transmission to the optical absorption cell, interaction with the gas therein, and finally being received by the quartz tuning fork and converted into an electrical signal, thus ensuring that the device can stably and accurately detect the gas concentration.

[0045] In this embodiment, the power amplifier 3 is preferably a high-gain, low-noise, wide-bandwidth semiconductor optical power amplifier, which can effectively amplify the optical signal power while reducing signal noise interference. Its wide-bandwidth characteristics can adapt to optical signals of different wavelengths, providing the device with a sufficiently strong and high-quality optical signal.

[0046] Filter 4 filters out light within a specific wavelength range from the amplified light signal, removes other stray light, and ensures that the light entering the light absorption cell is pure and effective light that matches the characteristic absorption peak of the target gas, thereby improving the accuracy and stability of the device in detecting the target gas.

[0047] In this embodiment, the filter 4 is preferably a tunable fiber Fabry-Perot (FP) filter, which features narrow bandwidth filtering, wavelength tunability, high resolution and low insertion loss. It can accurately filter out light in the target wavelength range, effectively remove stray light, and can be flexibly adjusted according to the light wavelength required for different gas detection, thereby improving the accuracy of detection.

[0048] Optical isolator 5 ensures that the optical signal is transmitted unidirectionally in a specific direction, preventing reflected light, stray light, etc. from entering the front-end optical path in reverse, preventing these interfering lights from affecting the normal operation of devices such as lasers and power amplifiers, ensuring the stability and reliability of the device's optical path system, and thus improving the accuracy of gas detection.

[0049] In this embodiment, the optical isolator 5 is preferably a Faraday rotary optical isolator, which has the characteristics of high isolation, wide wavelength range, low insertion loss and high stability. It can effectively prevent reverse light interference, ensure stable unidirectional transmission of optical signals, adapt to the optical path system in the device, and help the optical path to operate stably during the detection process.

[0050] Collimator 6 transforms divergent light into a parallel beam, improving the directionality and focusing of the light, enabling the light to more accurately illuminate the target gas, increasing the efficiency of light-gas interaction, and enhancing the performance of the entire detection system.

[0051] In this embodiment, the collimator 6 is preferably an optical fiber collimator, which features high-precision beam collimation, low insertion loss, wide wavelength adaptability and compact structure. It can efficiently collimate the light output from the optical fiber into a parallel beam, ensuring that the light propagates in the appropriate direction in the optical path of the device, and guaranteeing effective light transmission and accurate alignment during the detection process.

[0052] The light absorption cell 7 provides a stable containment space for the gas to be detected, and provides a stable and efficient gas-light interaction environment for photothermoelastic spectroscopy, thus laying the foundation for the subsequent process of converting light signals into electrical signals based on the thermoelastic effect of the quartz tuning fork, so as to achieve accurate detection of the gas.

[0053] In this embodiment, the light absorption cell 7 is preferably an anti-reflection coating, an optimized internal optical path, and a well-sealed light absorption cell, which can effectively reduce light reflection loss, increase the effective interaction path between light and gas, and ensure that the gas sample fully interacts with light in a stable environment. This is beneficial for improving the efficiency of photo-gas interaction during gas detection, thereby improving detection accuracy.

[0054] The reflector 8, positioned opposite to the filter 4, optical isolator 5, and collimator 6, reflects the light multiple times, extending the light propagation path within the cell 7 and enhancing the interaction between the light and gas molecules. This causes the gas molecules to absorb the light energy and produce a thermoelastic effect. In this embodiment, the reflector 8 is preferably a reflector with concave surfaces on opposite sides, which maximizes the utilization of light energy and improves the reliability of gas detection.

[0055] Specifically, reflectors 8 are symmetrically installed on the inner walls of both sides of the light absorption cell 7, and the center height of the reflectors 8 is consistent with the central axis height of the light absorption cell 7. The distance between the reflectors 8 is determined based on the length of the light absorption cell 7 and the detection requirements. If the length of the light absorption cell 7 is L, to ensure that the laser can be fully reflected within the light absorption cell 7 and enhance its interaction with gas molecules, the distance between the reflectors 8 can be set to be close to the length L of the light absorption cell. However, factors such as energy loss during laser reflection and installation space must be considered, and the value should be between (0.8-0.95)L. For example, when the length of the light absorption cell 7 is 50cm, the distance between the reflectors 8 can be set to 45cm. A shorter distance may result in insufficient laser reflections and inadequate interaction between the light and the gas; while a longer distance may increase laser transmission loss, reduce light intensity, and affect the detection effect.

[0056] The air inlet 9 allows the target gas to enter the light absorption cell 7 and fully interact with the detection light signal; the exhaust port 10 discharges the detected gas.

[0057] Lens 11 focuses the light passing through the light absorption cell 7 and adjusts the direction of light propagation, improving light energy utilization efficiency while ensuring that the light accurately acts on the quartz tuning fork 12 to enhance the photothermal elastic effect and improve the sensitivity and accuracy of gas detection. In this embodiment, lens 11 is preferably a convex lens.

[0058] Specifically, lens 11 is mounted on the side of the light emitting cell 7, with its center on the same horizontal line as the central axis of the light absorbing cell 7. The distance between lens 11 and the light absorbing cell 7 should ensure that the light emitted from the light absorbing cell 7, after being focused by lens 11, focuses precisely on the surface of the quartz tuning fork 12. The position of lens 11 is determined based on the divergence angle of the light emitted from the light absorbing cell 7 and the position of the quartz tuning fork 12. Assuming the divergence angle of the light emitted from the light absorbing cell is θ, and the distance from the quartz tuning fork 12 to the emitting surface of the light absorbing cell 7 is D, according to the focusing principle of lens 11, the distance d between lens 11 and the light absorbing cell 7 can be calculated using the formula d = D / (1 + cosθ). For example, when the divergence angle θ is 30° and the distance D from the quartz tuning fork 12 to the emitting surface of the light absorbing cell 7 is 20 cm, the distance d between lens 11 and the light absorbing cell 7 is approximately 17.3 cm.

[0059] This invention optimizes the configuration of the reflector 8 and the lens 11, so that the laser signal incident on the light absorption cell 7 and the laser signal acting on the quartz tuning fork 12 are on the same horizontal line. By focusing the laser signal, the sensitivity and reliability of gas detection are improved.

[0060] When light focused and oriented by a lens shines on the surface of the quartz tuning fork 12, thermal deposition and thermoelastic effects occur due to the diamond-like coating on the surface of the quartz tuning fork, causing the quartz tuning fork to deform. The piezoelectric effect of the quartz tuning fork itself will convert this deformation caused by photothermal elasticity into an electrical signal, thereby realizing the conversion from light energy to mechanical energy and then to electrical energy.

[0061] The transimpedance amplifier 13 amplifies the weak electrical signal generated by the photothermoelastic effect of the quartz tuning fork 12 and converts it into a signal with a suitable amplitude so that the subsequent lock-in amplifier can perform more accurate signal processing and analysis, providing strong signal support for the final accurate detection of gas.

[0062] The lock-in amplifier 14 further processes the signal output from the transimpedance amplifier. By selectively amplifying and phase-sensitively detecting the signal at a specific frequency, it effectively extracts the weak signal related to the target gas and suppresses noise and interference, thereby improving the accuracy and precision of gas detection.

[0063] Computer 15 is connected to lock-in amplifier 14, receives and processes signals from lock-in amplifier 14, and analyzes, stores and displays gas detection data through corresponding software and algorithms, realizing automated control, data processing and result presentation of gas detection process, and assisting users in accurately judging gas type and concentration; it is also connected to laser driver 16 to control and adjust the working parameters of laser 1, realizing automated control of detection system.

[0064] The laser driver 16 adjusts the power, wavelength, and other parameters of the laser 1 according to different detection requirements, thereby optimizing the detection performance of the system and ensuring that the entire detection system operates efficiently and accurately.

[0065] Example 2

[0066] This embodiment provides a specific application implementation of the diamond-like carbon coating-enhanced quartz tuning fork gas sensing device described in the above embodiment:

[0067] Computer 15 controls laser 1 to generate laser light of a specific wavelength via laser driver 16. The laser light passes sequentially through optical modulator 2 to modulate the intensity, frequency, or phase of the light; then through power amplifier 3 to amplify the optical power to meet the detection requirements; next, it passes through filter 4 to filter out light within the target wavelength range and remove stray light; then optical isolator 5 ensures unidirectional transmission of the optical signal and prevents interference from reflected light; finally, collimator 6 collimates the light into parallel light so that it can efficiently enter the optical absorption cell 7.

[0068] The collimated parallel light enters the light absorption cell 7. Reflectors 8, installed opposite each other within the cell, cause multiple reflections of the light, extending its propagation path and enhancing its interaction with the gas to be detected entering from the inlet 9. Gas molecules absorb the light energy, generating a thermoelastic effect. The light emitted from the light absorption cell 7 is focused by lens 11 onto a quartz tuning fork 12 coated with a diamond-like carbon layer. The photo-induced thermoelastic effect causes the quartz tuning fork 12 to deform, and based on its piezoelectric effect, this deformation is converted into a weak electrical signal. This weak electrical signal is initially amplified by transimpedance amplifier 13, converting it into an electrical signal with a suitable amplitude. The signal output from transimpedance amplifier 13 is transmitted to lock-in amplifier 14. Through selective amplification and phase-sensitive detection of signals at specific frequencies, the weak signal related to the target gas is extracted, and noise interference is suppressed. Finally, the processed signal is transmitted to computer 15, where it is analyzed, stored, and displayed to obtain the gas detection result. The detected gas is then discharged from exhaust port 10.

[0069] This embodiment also compares the proposed solution of the present invention with existing perovskite composite material coating solutions experimentally. For example... Figure 2 The figure shown is a gas detection curve of a prior art perovskite composite material coating scheme; Figure 3This is a detection curve diagram of the diamond-like carbon (DLC) coated and reinforced quartz tuning fork gas sensing device proposed in this application. It can be seen that the DLC-coated and reinforced quartz tuning fork gas sensing device proposed in this application is superior to existing coating solutions in terms of detection accuracy and anti-interference performance.

[0070] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A gas sensing device based on a diamond-like carbon coating-enhanced quartz tuning fork, comprising a laser signal emitting unit, a light absorption cell (7), a lens (11), a quartz tuning fork (12), and an electrical signal acquisition unit connected in sequence, characterized in that, The surface of the quartz tuning fork (12) is coated with a diamond-like coating; The target optical signal generated by the laser signal emitting unit is transmitted to the optical absorption cell (7). The light absorption cell (7) contains the target gas to be detected, and the light signal interacts with the target gas in the light absorption cell (7). The lens (11) is installed on the side of the light emitting cell (7). The center of the lens (11) is on the same horizontal line as the central axis of the light absorbing cell (7). The lens (11) focuses the light emitted from the light absorbing cell (7) onto the surface of a quartz tuning fork (12) coated with a diamond-like carbon coating. The distance between the lens (11) and the light absorbing cell (7) is: in, D The distance from the quartz tuning fork (12) to the exit surface of the light absorption cell (7); The divergence angle of the light emitted from the light absorption cell.

2. The quartz tuning fork gas sensing device based on diamond-like carbon coating reinforcement according to claim 1, characterized in that, The laser signal transmitting unit includes a laser (1), an optical modulator (2), a power amplifier (3), a filter (4), an optical isolator (5), and a collimator (6) connected in sequence by optical fibers. The optical centers of each unit are on the same horizontal line, and the optical absorption cell (7) is opposite to the collimator (6).

3. The quartz tuning fork gas sensing device based on diamond-like carbon coating reinforcement according to claim 2, characterized in that, The optical modulator (2) modulates the characteristics of the laser output from the laser (1) to change the energy and variation of the light irradiating the surface of the quartz tuning fork (12). The filter (4) filters the wavelength of the light signal so that the light entering the light absorption cell (7) matches the characteristic absorption peak of the target gas.

4. The quartz tuning fork gas sensing device based on diamond-like carbon coating reinforcement according to claim 1, characterized in that, The light absorption cell (7) is provided with an anti-reflection coating. Two reflectors (8) are symmetrically installed on the inner walls of both sides of the light absorption cell (7). The center height of the reflectors (8) is consistent with the center axis height of the light absorption cell (7).

5. A quartz tuning fork gas sensing device based on a diamond-like carbon coating as described in claim 4, characterized in that, The distance between the two reflectors (8) is set between 0.8 and 0.95 of the length of the light absorption cell.

6. The quartz tuning fork gas sensing device based on diamond-like carbon coating reinforcement according to claim 1, characterized in that, The light absorption cell (7) is symmetrically equipped with an air inlet (9) and an exhaust outlet (10); the target gas to be detected enters the light absorption cell 7 through the air inlet (9), and the detected gas is discharged from the exhaust outlet (10).

7. The quartz tuning fork gas sensing device based on diamond-like carbon coating reinforcement according to claim 1, characterized in that, The electrical signal acquisition unit includes sequentially connected data... The transimpedance amplifier (13) amplifies the electrical signal generated by the quartz tuning fork (12); The lock-in amplifier (14) selectively amplifies and phase-sensitively detects the signal output by the transimpedance amplifier (13) at a specific frequency, and extracts the weak signal related to the target gas. The computer (15) receives and processes signals from the lock-in amplifier (14) and analyzes, stores and displays the gas detection data.

8. A quartz tuning fork gas sensing device based on a diamond-like carbon coating as described in claim 7, characterized in that, The sensing device also includes a laser driver (16), which is signal-connected to the laser (1) and the computer (15) and is used to adjust the laser output parameters of the laser (1) according to the detection requirements.

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