Fluorescence interference prevention laser radar device

Abstract

The utility model provides an anti-fluorescence interference laser radar device, which comprises a receiving window sheet arranged at the upper end of a window sheet fixing seat; and the transmitting window sheet is mounted on the receiving window sheet through a transmitting window sheet fixing structure. Therefore, the transmitting window piece and the receiving window piece are arranged in a split and isolated manner, and the scattering phenomenon of the transmitting window piece is prevented from being transmitted to the receiving window piece, so that the influence of scattered light on received signals is reduced, the fluorescence interference is eliminated, the accuracy of the received signals is ensured, and the credibility of data is improved.

Description

Technical Field

[0001] The embodiments of this disclosure generally relate to the field of atmospheric monitoring equipment technology, and more specifically, to a lidar device that is resistant to fluorescence interference. Background Technology

[0002] In recent years, global energy consumption has increased year by year, and the air pollution situation is severe. LiDAR is widely used to detect atmospheric aerosols, visibility, boundary layer, ozone and other parameters. In order to improve the measurement progress and service life of lidar, lidar is usually installed inside a container. It uses laser as a light source and emits it into the atmosphere through a skylight. The laser is scattered and absorbed by the atmosphere. The backscattered signal is then received by the lidar telescope through the skylight glass. It is converted into an electrical signal by a photodetector. Through data acquisition and algorithm inversion, information on atmospheric molecules and aerosol particles is obtained.

[0003] The physical mechanism behind Raman spectroscopy is Raman scattering. When a sample is irradiated with excitation light of a certain frequency, some incident photons undergo elastic collisions with sample molecules, emitting elastically scattered light. This type of scattering does not involve energy exchange and is called Rayleigh scattering. Other incident photons undergo inelastic collisions with sample molecules, resulting in energy transfer. This type of scattering is called Raman scattering.

[0004] When a substance is irradiated by a laser and absorbs photons of certain characteristic frequencies, it can transition from the ground state to different vibrational-rotational energy levels of the first electronically excited state or the higher electronically excited state. Molecules in the electronically excited state descend to the lowest energy level of the first electronically excited state through relaxation processes such as thermal vibration, and then transition from this lowest energy level to various vibrational-rotational energy levels of the ground state and emit fluorescence. The fluorescence spectrum has a wide range and usually overlaps with the Raman spectrum in the instrument. It cannot be suppressed by filters, and the presence of fluorescence will drown out the Raman signal, making Raman spectroscopy undetectable.

[0005] Therefore, given the impact of fluorescence on lidar detection operations, there is an urgent need for a lidar device that can prevent fluorescence interference. Utility Model Content

[0006] To address or at least partially address the aforementioned deficiencies, according to embodiments of this disclosure, an anti-fluorescence interference lidar device is provided, which can avoid fluorescence interference and improve the accuracy of detection results.

[0007] Specifically, the anti-fluorescence interference lidar device includes: a receiving window, which is disposed at the upper end of the window fixing base;

[0008] The transmitting window is mounted on the receiving window via a transmitting window fixing structure, thereby isolating the transmitting window from the receiving window.

[0009] According to the aspect and any possible implementation manner as above, further provided is an implementation manner, the emitting window piece fixing structure is arranged as an emitting window piece fixing cylinder,

[0010] The receiving window piece is formed with an emitting window piece mounting hole, the emitting window piece fixing cylinder penetrates the emitting window piece mounting hole of the receiving window piece, and the emitting window piece is arranged at the upper end of the emitting window piece fixing cylinder.

[0011] According to the aspect and any possible implementation manner as above, further provided is an implementation manner, the inner side wall surface of the emitting window piece fixing cylinder is arranged as black and formed with light extinction lines to eliminate reflected light of the emitting window piece.

[0012] According to the aspect and any possible implementation manner as above, further provided is an implementation manner, a sealing ring is arranged between the emitting window piece fixing cylinder and the upper contact surface of the receiving window piece.

[0013] A nylon gasket is arranged between the emitting window piece fixing cylinder and the lower contact surface of the receiving window piece, and the lower end of the nylon gasket is arranged with a locking ring locked with the emitting window piece fixing cylinder.

[0014] According to the aspect and any possible implementation manner as above, further provided is an implementation manner, the emitting window piece is fixed at the upper end of the emitting window piece fixing cylinder through a compression ring matched with an O-shaped ring, and the O-shaped ring is mounted in a compression ring clamping groove.

[0015] According to the aspect and any possible implementation manner as above, further provided is an implementation manner, the upper surface of the window piece fixing seat is arranged with a limiting structure corresponding to the receiving window piece to be positioned and fixed with each other.

[0016] According to the aspect and any possible implementation manner as above, further provided is an implementation manner, the upper end of the window piece fixing seat is arranged as inclined, and the inclined angle of the upper end of the window piece fixing seat is arranged to be matched with the inclined angle of the receiving window piece.

[0017] According to the aspect and any possible implementation manner as above, further provided is an implementation manner, the upper end of the emitting window piece fixing cylinder is arranged as inclined, and the inclined angle of the upper end of the emitting window piece fixing cylinder is arranged to be matched with the inclined angle of the emitting window piece.

[0018] According to the aspect and any possible implementation manner as above, further provided is an implementation manner, the receiving window piece and the emitting window piece adopt quartz glass.

[0019] According to the aspect and any possible implementation manner as above, further provided is an implementation manner, the emitting window piece fixing structure adopts a light-proof metal material.

[0020] According to the embodiments of the present disclosure, the following technical effects are achieved:

[0021] 1. In the prior art, laser emission is through the sunroof glass, and the laser wavelength used is in the ultraviolet band, so it will cause fluorescence interference. In the present embodiment, the emission area (emission window piece) and the receiving area (receiving window piece) are separately arranged, which forms a physical isolation through the structural member, blocks the scattering phenomenon of the emission window piece from being transmitted to the receiving window piece, and the emission window piece fixing cylinder is made of light-proof metal, and the inner wall of the emission window piece is blackened and processed with light extinction lines to reflect light, so that the emission window piece and the receiving window piece of the present system reduce the influence of scattered light on the received signal in the detection work, eliminate the reflected light of the emission window piece, avoid the influence of fluorescence effect on the received signal, and realize the elimination of fluorescence interference.

[0022] 2. In the prior art, the size of the sunroof glass is large, so the surface accuracy can only reach one wavelength. In the present embodiment, the center window piece can be reduced to two inches through isolation processing, so that the surface accuracy can be improved by 10 times. The improvement of the surface reduces the scattering influence, further reduces the interference of the nearby miscellaneous flashes, and improves the detection accuracy.

[0023] 3. In order to improve the water vapor detection distance, the emission laser energy needs to reach hundreds of millijoules, and the stronger the emission laser is, the more likely it is to cause damage to the window piece, especially the side in contact with the atmosphere, which is inevitably attached with pollutants, and the attachment of pollutants aggravates the damage degree. Therefore, the sunroof in the high-energy laser radar system needs to be replaced regularly. If the sunroof is replaced as a whole, the cost is high, and the operation is not convenient. The present embodiment adopts a split window piece, and the emission window piece and the receiving window piece are isolated, so that only the middle emission window piece needs to be replaced, which is simple to maintain and greatly reduces the maintenance cost.

[0024] 4. The small area window piece can be processed to have a higher precision surface, and better processing can be easily realized. Through split processing, the emission laser can be better and the divergence angle can be smaller.

[0025] 5. The center emission window piece can be independently inclined, compared with the overall inclination, the center small window piece can control the inclination angle, so that the inclination angle of the receiving window piece is reduced, and better receiving effect is obtained.

[0026] 6. The center emission window piece can be higher than the surrounding receiving window piece, which reduces the attachment of water droplets and has less influence in rainy weather.

[0027] It should be understood that the content described in the utility model content part is not intended to limit the key or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become apparent through the following description. BRIEF DESCRIPTION OF DRAWINGS

[0028] The above and other features, advantages, and aspects of the present disclosure will become more apparent by describing in detail the embodiments thereof with reference to the annexed drawings in which:

[0029] Figure 1 A structure schematic diagram of the anti-fluorescent interference laser radar device provided by the embodiment of the present application is shown;

[0030] Figure 2 A cross-sectional structure schematic diagram of the anti-fluorescent interference laser radar device provided by the embodiment of the present application is shown;

[0031] Figure 3 A center part structure cross-sectional schematic diagram of the anti-fluorescent interference laser radar device provided by the embodiment of the present application is shown;

[0032] Figure 4 A structure diagram of the emission window sheet of the anti-fluorescent interference laser radar device provided by the embodiment of the present application is shown;

[0033] Figure 5 A comparison diagram of application effects of the present device and a conventional integral window sheet is shown;

[0034] Figure 6 A water vapor detection precision diagram of fluorescent interference influence when a conventional integral window sheet is applied is shown.

[0035] Corresponding relationship between the reference signs and the component names in the drawings is as follows: Figures 1 to 4

[0036] 1, receiving window sheet; 2, window sheet fixing seat; 3, sealing strip; 4, decorative frame; 5, emission window sheet; 6, emission window sheet fixing cylinder; 7, sealing ring; 8, pressing ring, 9, O-ring; 10, nylon gasket; 11, locking ring. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present disclosure.

[0038] ​In addition, the term "and / or" used in the present document is only used to describe the relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the existence of A alone, the existence of A and B simultaneously, and the existence of B alone. In addition, the character " / " in the present document generally represents an "or" relationship between the front and rear associated objects.

[0039] In the present disclosure, a fluorescence interference prevention laser radar device is provided, the emission window sheet and the receiving window sheet are arranged in a split type, the emission window sheet and the receiving window sheet are isolated, and the receiving window sheet and the central emission window sheet are isolated by the emission window sheet fixing structure made of light-proof metal, the scattering phenomenon of the emission window sheet is blocked from being transmitted to the receiving window sheet, the influence of scattered light on the receiving signal is reduced, the fluorescence interference is eliminated as much as possible, the accuracy of the receiving signal is ensured, and the reliability of the data is improved.

[0040] The embodiments of the present application will be described below with reference to Figures 1 to 4 to provide a fluorescence interference prevention laser radar device.

[0041] As shown in Figure 1 , the fluorescence interference prevention laser radar device provided by the present application comprises a receiving window sheet 1, a window sheet fixing seat 2, a sealing strip 3, a decorative frame 4, an emission window sheet 5, an emission window sheet fixing cylinder 6, a sealing ring 7, a pressing ring 8, an O-shaped ring 9, a nylon gasket 10 and a locking ring 11.

[0042] Specifically, as shown in Figure 1 , the receiving window sheet 1 is arranged at the upper end of the window sheet fixing seat 2, and preferably, the receiving window sheet 1 is fixed to the window sheet fixing seat 2 by glass glue. The upper surface of the window sheet fixing seat 2 and the receiving window sheet 1 can be provided with corresponding limiting structures, for example, as shown in Figure 1 , the four peripheral edges of the receiving window sheet 1 can form an extension part protruding to one side of the window sheet fixing seat 2 and then extending horizontally outward, so that when the receiving window sheet 1 is relatively covered on the window sheet fixing seat 2, the extension part at the edge of the receiving window sheet 1 can limit its deviation from the window sheet fixing seat 2; or, a fixing hole is formed in the extension part of the receiving window sheet 1, and a corresponding protrusion is formed on the side surface of the upper part of the window sheet fixing seat 2, so that the receiving window sheet 1 and the window sheet fixing seat 2 can be connected by buckling. Therefore, through the limiting structure of the receiving window sheet 1 and the window sheet fixing seat 2, the positioning and fixing between the receiving window sheet 1 and the window sheet fixing seat 2 are facilitated, the installation of the receiving window sheet 1 is more convenient, and the quartz glass receiving window sheet 1 can also be prevented from sliding during the gelation process when using adhesive fixation.

[0043] The receiving window sheet 1 is made of quartz glass, which can transmit ultraviolet light and infrared light and has high spectral transmittance.

[0044] The window piece fixing seat 2 is made of stainless steel and is painted on the surface. It has good reliability, corrosion resistance, durability and appearance selection. The upper end of the window piece fixing seat 2 is inclined. The inclination angle of the upper end of the window piece fixing seat 2 formed by the height of the side wall of the window piece fixing seat 2 is matched with the inclination angle of the received window piece 1 according to actual needs.

[0045] A sealing strip 3 extending outward is arranged around the lower part of the window piece fixing seat 2. The sealing strip 3 is provided with a fixing hole. A self-tapping screw is used to fix the window piece fixing seat 2 to the top of the detection shelter through the fixing hole. A decorative frame 4 is arranged on the lower side of the window piece fixing seat 2 and is installed in cooperation with the window piece fixing seat 2. It has good visibility and is beautiful. The decorative frame 4 is formed with a frame extending to one side of the window piece fixing seat 2 in the longitudinal direction and a sealing strip extending outward from the lower end of the frame. Alternatively, the decorative frame 4 can be provided with a bottom surface at the lower end of the frame. The size of the frame is slightly larger than that of the window piece fixing seat 2, so that a part of the lower part of the window piece fixing seat 2 is embedded in the frame of the decorative frame 4. Alternatively, the size of the frame is slightly smaller than that of the window piece fixing seat 2, so that the frame of the decorative frame 4 is embedded in the lower part of the window piece fixing seat 2.

[0046] Furthermore, the sealing strip 3 of the window piece fixing seat 2 is arranged at a distance from the lower end of the window piece fixing seat 2. When the window piece fixing seat 2 is embedded in the decorative frame 4, the sealing strip 3 of the window piece fixing seat 2 abuts against the sealing strip of the decorative frame 4. The sealing strip 3 of the window piece fixing seat 2 and the sealing strip of the decorative frame 4 are respectively formed with opposite fixing holes. A self-tapping screw is used to fix the sealing strip 3 of the window piece fixing seat 2 and the sealing strip of the decorative frame 4 to the top of the detection shelter.

[0047] Furthermore, glass glue can be used to seal the joint between the window piece fixing seat 2 and its sealing strip 3, the joint between the decorative frame 4 and its sealing strip, and the joint between the sealing strip 3 of the window piece fixing seat 2 and the sealing strip of the decorative frame 4, to ensure waterproof sealing.

[0048] As shown in Figure 2 , 3 , the transmitting window piece 5 is arranged at the center of the receiving window piece 1. The receiving window piece 1 and the transmitting window piece 5 are independent structures and are assembled separately and isolated from each other. The transmitting window piece 5 is installed on the receiving window piece 1 through a transmitting window piece fixing cylinder 6.

[0049] The receiving window sheet 1 is formed with a transmitting window sheet mounting hole, the transmitting window sheet fixing cylinder 6 is arranged through the transmitting window sheet mounting hole of the receiving window sheet 1, the transmitting window sheet fixing cylinder 6 extends from the upper outer side of the receiving window sheet 1 to the inner side of the receiving window sheet 1, and the transmitting window sheet 5 is arranged at the upper end of the transmitting window sheet fixing cylinder 6. The transmitting window sheet 5 is arranged higher than the receiving window sheet 1 through the transmitting window sheet fixing cylinder 6. A sealing ring 7 is arranged between the transmitting window sheet fixing cylinder 6 and the upper contact surface of the receiving window sheet 1, and the sealing ring 7 is arranged around the outer side wall surface of the transmitting window sheet fixing cylinder 6. A nylon washer 10 is arranged between the transmitting window sheet fixing cylinder 6 and the lower contact surface of the receiving window sheet 1, the nylon washer 10 is arranged around the outer side wall surface of the transmitting window sheet fixing cylinder 6, the lower end of the nylon washer 10 is provided with a locking ring 11, and the locking ring 11 is threadedly locked with the transmitting window sheet fixing cylinder 6. The nylon washer 10 is arranged between the receiving window sheet 1 and the locking ring 11, and functions as a buffer and facilitates locking. The outer peripheral surface of the transmitting window sheet fixing cylinder 6 is partially formed with threads, so that the locking ring 11 is threadedly locked with the transmitting window sheet fixing cylinder 6, and the transmitting window sheet fixing cylinder 6 is locked and fixed through the locking ring 11. The installation is simple, reliable, easy to maintain, and good in sealing performance.

[0050] The transmitting window sheet fixing cylinder 6 can be customized according to the inclined angle of the transmitting window sheet 5, the diameter of the transmitting window sheet 5 and the required shielding length, and meets different requirements. Figure 2 、 3 The upper end of the transmitting window sheet fixing cylinder 6 is arranged obliquely, so that the transmitting window sheet 5 is arranged obliquely at a certain angle on the upper end of the transmitting window sheet fixing cylinder 6.

[0051] The transmitting window sheet 5 is fixed on the upper end of the transmitting window sheet fixing cylinder 6 by a pressing ring 8 and an O-shaped ring 9. The O-shaped ring is made of rubber material and is arranged in a pressing ring clamping groove on the lower surface of the pressing ring 8, functions as a sealing ring, and fixes the transmitting window sheet 5 through the pressing ring 8. Preferably, the pressing ring 8 is threadedly pressed on the upper end of the transmitting window sheet fixing cylinder 6.

[0052] The transmitting window sheet fixing cylinder 6 is made of aluminum alloy, can meet different inclined angles of the transmitting window sheet through processing, and is provided with a black inner side wall surface and a spiral light extinction pattern formed on the inner side wall surface, so as to eliminate the reflected light of the transmitting window sheet.

[0053] The transmitting window sheet 5 is made of quartz glass, can transmit ultraviolet light and infrared light, and has high spectral transmittance. A small area of the transmitting window sheet can be used, the size of the transmitting window sheet is small, the processing performance is better, and higher precision can be obtained. Meanwhile, the window sheet has a T-shaped structure, and is convenient to install and fix.

[0054] As shown in Figure 5As shown in the figure, this is a comparison of the effects of using a conventional overall window and this device. The graph displays the backscattered signal intensity profile of the water vapor channel. The upper part of the graph shows an upward tilt in the signal value at 4km. The reason for this upward tilt and stronger signal at high altitudes is the false signal from fluorescence. This false signal is used as a water vapor signal for inversion, leading to an inflated water vapor measurement. The lower part of the graph shows that after using this device, the upward tilt in the signal beyond 4km is no longer observed; that is, the fluorescence signal disappears. Therefore, this device effectively reduces the impact of fluorescence interference on the received signal and improves the accuracy of detection.

[0055] like Figure 6 As shown in the figure, this plot represents the data observed using a conventional skylight structure. The results show that the water vapor mixing ratio measured by lidar is significantly higher than that measured by sounding data beyond 4 km. The reason for this result, combined with... Figure 5 As can be seen from the original profile, the signal is relatively weak after 4km. At this time, the interference signal of fluorescence becomes the main signal. This false signal leads to the deviation of the inversion results.

[0056] According to the embodiments of this disclosure, the following technical effects are achieved:

[0057] 1. In existing solutions, laser emission occurs through a skylight glass, and the laser wavelength used is in the ultraviolet band, which can cause fluorescence interference. In this embodiment, by separating the emitting area (emitting window 5) and the receiving area (receiving window 1), physical isolation is achieved through structural components. Furthermore, the emitting window fixing cylinder 6 is made of opaque metal, and the inner wall of the emitting window is blackened and processed with matte textures to eliminate reflective light. Therefore, during detection, the scattering phenomenon from the emitting window is blocked from reaching the receiving window, eliminating reflected light from the emitting window and preventing the fluorescence effect from affecting the received signal, thus eliminating fluorescence interference.

[0058] 2. In existing solutions, the surface accuracy is limited to one wavelength due to the large size of the skylight glass. This implementation, however, uses isolation processing to reduce the central window to two inches, thus improving surface accuracy tenfold. This improved surface accuracy reduces scattering effects, further minimizing interference from near-field stray light and enhancing detection accuracy.

[0059] 3. To improve the water vapor detection range, the emitted laser energy needs to reach the hundreds of millijoules level. The stronger the emitted laser, the more easily it damages the window, especially the side in contact with the atmosphere, where pollutants inevitably accumulate, exacerbating the damage. Therefore, the window in a high-energy lidar system needs to be replaced periodically. Replacing the entire window is costly and inconvenient. This implementation uses a split window design, with the emitting and receiving windows isolated. This allows for replacement only of the middle emitting window, simplifying maintenance and significantly reducing costs.

[0060] 4. Smaller window panels can be processed to produce higher precision surfaces, making them easier to process. Through split processing, laser emission can be improved and the divergence angle can be reduced.

[0061] 5. The central transmitting window can be tilted independently. Compared with the overall tilt, the tilt angle of the central small window can be controlled, thereby reducing the tilt angle of the receiving window and obtaining better reception effect.

[0062] 6. The central transmitting window can be higher than the surrounding receiving windows, reducing the adhesion of water droplets and having less impact on use in rainy weather.

[0063] In the description of this specification, the terms "connection," "installation," and "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0064] In this specification, the terms "one embodiment," "some embodiments," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0065] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A laser radar device for preventing fluorescence interference, characterized in that, include: The receiving window is located at the upper end of the window fixing seat; The transmitting window is mounted on the receiving window via a transmitting window fixing structure, thereby isolating the transmitting window from the receiving window.

2. The anti-fluorescence interference lidar device according to claim 1, characterized in that, The launching window fixing structure is configured as a launching window fixing cylinder. The receiving window has a transmitting window mounting hole, and the transmitting window fixing cylinder passes through the transmitting window mounting hole, placing the transmitting window at the upper end of the transmitting window fixing cylinder.

3. The anti-fluorescence interference lidar device according to claim 2, characterized in that, The inner wall of the firing window fixing cylinder is black and has a matte texture.

4. The anti-fluorescence interference lidar device according to claim 2, characterized in that, A sealing ring is provided between the transmitting window fixing cylinder and the contact surface of the receiving window; A nylon washer is provided between the transmitting window fixing cylinder and the lower contact surface of the receiving window, and a locking ring is provided at the lower end of the nylon washer to lock it to the transmitting window fixing cylinder.

5. The anti-fluorescence interference lidar device according to claim 2, characterized in that, The emitting window is fixed to the upper end of the emitting window fixing cylinder by a pressure ring and an O-ring, with the O-ring installed in the pressure ring groove.

6. The anti-fluorescence interference lidar device according to claim 1, characterized in that, The upper surface of the window fixing seat and the receiving window are provided with corresponding limiting structures for mutual positioning and fixation.

7. The anti-fluorescence interference lidar device according to claim 1, characterized in that, The upper end of the window slat fixing seat is inclined, and the inclination angle of the upper end of the window slat fixing seat is set to match the inclination angle of the receiving window slat.

8. The anti-fluorescence interference lidar device according to claim 2, characterized in that, The upper end of the launching window fixing cylinder is inclined, and the inclination angle of the upper end of the launching window fixing cylinder is set to match the setting angle of the launching window.

9. The anti-fluorescence interference lidar device according to claim 1, characterized in that, The receiving window and the transmitting window are made of quartz glass.

10. The anti-fluorescence interference lidar device according to claim 1, characterized in that, The fixing structure of the emission window is made of opaque metal.

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