Laser radar receiving unit and laser radar system
By optimizing the optical component layout and sealing design of the lidar receiver unit, the problems of large space occupation and structural instability of Ramanmi-micropulse lidar after adding polarization detection channels were solved, achieving miniaturization and improved stability of lidar.
Patent Information
- Application Number
- CN202520013354.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-03
- Publication Date
- 2026-02-10
- Estimated Expiration
- 2035-01-03
AI Technical Summary
Existing Raman-micropulse lidars, after adding polarization detection channels, occupy a large space and have unstable structures, affecting optical signal reception and making it difficult to achieve both miniaturization and stability.
A lidar receiving unit is designed. Through the rational layout of cemented lenses, reflector assemblies, and receiving optical path assemblies, polarizers and detectors are fixed inside the telescope housing, optimizing space utilization and enhancing stability. The combination of optical elements such as anti-reflection coatings, reflectors, plano-convex lenses, and beam splitters forms a sealed downstream dark box to prevent interference.
The addition of a polarization detection channel has enabled miniaturization and improved structural stability of the lidar, enhanced anti-interference capabilities, and ensured stable reception of optical signals.
Smart Images
Figure CN223897639U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to the technical field of laser radar, especially relates to a laser radar receiving unit and laser radar system. BACKGROUND
[0002] Laser radar is used to emit laser into the atmosphere, receive the echo signal generated by the interaction of the atmosphere and laser through the telescope, and monitor and judge the degree of atmospheric pollution or atmospheric composition by analyzing the echo signal.
[0003] Among them, the relatively low-cost Raman-microwave pulse laser radar combines the principles of Raman scattering and Mie scattering, as well as micro-pulse laser technology. It has the characteristics of high resolution, high sensitivity and high accuracy, and can be used in fields such as atmospheric environment monitoring, weather forecasting, and climate change research.
[0004] In order to meet the specific detection requirements, polarizing elements such as polarizers are often used to convert the light emitted by the laser into linearly polarized light. For example, in the polarization Raman laser radar transmission and reception system, the polarizer is used to improve the linear polarization purity of the laser emitted by the laser, so as to ensure that the polarization characteristics of the transmitted light meet the requirements of subsequent detection and data processing. For example, atmospheric polarization signals are very important and irreplaceable for atmospheric remote sensing, so almost all laser radar systems will add a polarization detection channel. How to connect the polarization detection channel with the laser radar to ensure stable performance is a technical problem that needs to be solved. Utility model content
[0005] In order to ensure stable performance on the basis of adding a polarization detection channel, the utility model provides a laser radar receiving unit and a laser radar system, and the specific technical scheme is as follows:
[0006] A laser radar receiving unit, comprising:
[0007] A cemented lens for focusing the light beam entering the telescope;
[0008] A mirror assembly comprising a plurality of mirrors for entering the focused light beam into the receiving light path assembly;
[0009] A receiving light path assembly is arranged in the telescope space between the cemented lens and the mirror assembly, and the receiving light path assembly is used to receive the light beam reflected by the mirror assembly; the receiving light path assembly is arranged in the direction parallel to the central axis of the telescope and towards the entrance of the telescope to form a receiving main light path; a polarizer is arranged on the receiving main light path;
[0010] A detection assembly comprising a first analog detector arranged at a position away from the cemented lens and in the polarization direction of the polarizer, for receiving a polarized light beam in one of the two perpendicular polarization directions of the polarizer.
[0011] Furthermore, the reflector assembly includes a first reflector and a second reflector arranged sequentially along the optical path. The first reflector reflects the light beam focused by the cemented lens onto the second reflector.
[0012] Furthermore, the receiving optical path assembly includes a small aperture stop disposed at the position where the second reflector reflects the light beam.
[0013] Furthermore, a plano-convex lens is provided behind the aperture stop, and the plano-convex lens is a hard-film bandpass filter.
[0014] Furthermore, it includes a window on the telescope input port, the window having an anti-reflective coating attached.
[0015] Furthermore, it also includes a follow-up dark box, which has a first mounting hole on the outer surface of the second reflector.
[0016] Furthermore, a beam splitter is also provided on the main receiving optical path behind the plano-convex lens. The beam splitter splits a first beam and a second beam into perpendicular beams. The first beam is split by a photometer mounted on a second mounting hole in the subsequent dark box to measure the number of beam molecules, and the second beam is then emitted onto the device on the main receiving optical path. In this embodiment, the second beam is emitted onto the polarizer.
[0017] Furthermore, the polarizer is disposed inside the mounting box. One end of the mounting box receives the second beam splitter that has passed through the bandpass filter and emits it onto the polarizer. The polarizer polarizes the second beam splitter into a first polarized beam and a second polarized beam. The first polarized beam is detected by a first analog detector, and the second polarized beam is emitted into the device after receiving the main optical path.
[0018] A converging lens is also provided on the main receiving optical path to converge the second polarized beam. The detection assembly further includes a second analog detector, which is positioned at the location of the second beam split off from the converging lens and is located on the main receiving optical path.
[0019] Furthermore, the pinhole aperture is disposed inside the sleeve assembly, the sleeve assembly is fixed on the side fixing bracket, and a partition plate for blocking stray light is disposed in the gap between the side fixing bracket and the telescope housing.
[0020] A lidar system includes a lidar receiving unit as described in any one of the above claims, and further includes a laser for emitting a laser beam.
[0021] The advantages of this utility model are:
[0022] (1) The layout and fixation of each component in the telescope housing in this application can effectively integrate space, so as to ensure the structural stability of the receiving unit after adding polarization detection channels, and effectively integrate space to achieve miniaturization of the receiving unit.
[0023] (2) Strong anti-interference capability; The first layer of protection is the radar shell and lens. The first layer of protection forms a relatively closed internal space for the radar. However, sometimes due to poor airtightness, water vapor will enter, forming fog and increasing humidity. The second layer of protection is the protection of the subsequent dark box. The optical components are fixed in the subsequent dark box. The stability is better than the previous version. The subsequent dark box and the telescope are designed as an integrated unit. The radar receiving part is sealed to prevent noise from interfering with the signal. Attached Figure Description
[0024] Figure 1 This is a structural cross-sectional view of a lidar receiving unit in one embodiment.
[0025] Figure 2 This is a perspective view of a lidar receiving unit in one embodiment.
[0026] In the picture:
[0027] 1. Cemented lens; 2. Telescope housing; 3. Telescope mounting plate; 4. First reflecting mirror; 5. Subsequent dark box; 51. First mounting hole; 52. Second mounting hole; 6. Partition plate; 7. Second reflecting mirror; 8. Sleeve; 9. Beam splitter; 10. Bandpass filter; 11. Polarizer; 12. Mounting box; 121. Third mounting hole; 20. Converging lens; 21. Sleeve assembly; 22. Side mounting bracket. Detailed Implementation
[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In the description of the embodiments of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0029] Raman-Mie micropulse lidar is a lidar technology that combines the principles of Raman scattering and Mie scattering with micropulse laser technology. It features high resolution, high sensitivity, and high accuracy, and can be used in fields such as atmospheric environment monitoring, weather forecasting, and climate change research.
[0030] When Raman-micropulse lidar detects atmospheric polarization signals, a polarization detection channel is added. The proper use of polarization elements helps improve the Raman-micropulse lidar's ability to detect weak signals. Through precise control of the polarization state and effective signal separation, signals related to atmospheric composition and particle characteristics can be detected more sensitively in complex atmospheric environments, thus achieving a more comprehensive and in-depth detection of the atmospheric environment.
[0031] To achieve the installation between the Raman-micropulse lidar and the polarization detection channel, such as Figure 1 As shown, the telescope in the Raman-micropulse lidar is connected to many structural components by a sleeve 8, and is completely suspended inside the lidar. Because the focus needs to be adjusted, it cannot be completely fixed, which not only occupies a large space, but also makes the structure unstable in its suspended state, easily damaging the internal structure of the Raman-micropulse lidar. Moreover, even a slight deviation will affect the received optical signal. In addition, since the lidar needs to achieve laser detection while miniaturizing itself, adding polarization detection channels will inevitably increase the overall space of the lidar.
[0032] Therefore, it is necessary to design an assembly for the polarization-splitting signal of the Raman-micropulse lidar optical receiving unit, and to optimize the Raman-micropulse laser telescope and polarization detection channel. Based on this, such as Figure 1 and Figure 2 As shown, this application discloses a lidar receiving unit, including:
[0033] Cemented lens 1 is used to focus the light beam entering the telescope;
[0034] A reflector assembly, comprising multiple reflectors, is used to direct a focused light beam into a receiving optical path assembly;
[0035] A receiving optical path assembly is disposed in the telescope space between the cemented lens 1 and the reflector assembly. The receiving optical path assembly is used to receive the light beam reflected by the reflector assembly. The receiving optical path assembly is arranged in a direction parallel to the central axis of the telescope and facing the telescope entrance to form a main receiving optical path. A polarizer 11 is disposed on the main receiving optical path.
[0036] The detection component includes a first analog detector positioned along the polarization direction of the polarizer 11 and away from the cemented lens 1, for receiving and measuring a beam of polarized light in one of the two perpendicular polarization directions of the polarizer 11.
[0037] This application uses a cemented lens 1 to focus the light beam entering the telescope onto the reflector assembly. The reflector assembly then changes the beam direction, making it parallel to the telescope's central axis and pointing towards the telescope entrance. This better utilizes the space in the receiving unit. Furthermore, the reflector assembly, the receiving optical path assembly, and the detection assembly can all be fixed inside the telescope housing 2, saving space and preventing the detection assembly from being suspended, thus ensuring the stability of the equipment. The telescope housing 2 is fixed to the support component by a telescope mounting plate 3.
[0038] In one embodiment, the receiving unit includes a window on the telescope input port, the window having an anti-reflection coating. The anti-reflection coating reduces reflections, thereby increasing the telescope's light transmittance. This structure ensures light transmission and the propagation of transmitted waves while protecting circuit boards and other electronic instruments from environmental influences.
[0039] In one embodiment, the window panel is fixed to the flange by adhesive, the flange is fixed to the U-shaped frame, the flange and the U-shaped frame are fixed with screws, and a sealing strip (not shown in the figure) is added in the middle.
[0040] In one embodiment, the reflector assembly includes a first reflector 4 and a second reflector 7 arranged sequentially along the optical path. The first reflector 4 reflects the light beam focused by the cemented lens 1 onto the second reflector 7, thereby changing the direction of the light beam emitted by the cemented lens 1 to a direction parallel to the receiving optical path assembly.
[0041] In one embodiment, the cemented lens 1 is mounted on the telescope body, the distance between the cemented lens 1 and the first reflector 4 is 370 mm, the distance between the first reflector 4 and the second reflector 7 is 90 mm, the size of the first reflector 4 is 2 inches, and the size of the second reflector 7 is 1 inch.
[0042] In another embodiment, the receiving optical path assembly includes a pinhole aperture disposed at the position where the second reflector 7 reflects the light beam. The pinhole aperture is made of stainless steel, and the pinhole is a circular pinhole. In yet another embodiment, the diameter of the pinhole in the pinhole aperture is 200 μm, and the distance between the second reflector 7 and the center of the pinhole aperture is 20.877 mm. The first reflector 4 and the second reflector 7 are fixed to the telescope housing 2 by a subsequent dark box 5.
[0043] In another embodiment, a plano-convex lens is further disposed after the pinhole aperture, the plano-convex lens being a hard-film bandpass filter 10. The pinhole aperture and the bandpass filter 10 are connected by an aperture sleeve 8. In yet another embodiment, the center distance between the plano-convex lens and the pinhole aperture is 45.467 mm.
[0044] In one embodiment, the aperture stop is disposed within the sleeve 8 assembly, which is fixed to the side mounting bracket 22. A baffle plate 6 for blocking stray light signals is provided in the gap between the side mounting bracket 22 and the telescope housing 2. The sleeve 8 assembly includes an aperture sleeve 8, an M30 locking ring, and an eyepiece sleeve 8. The aperture sleeve 8 and the eyepiece sleeve 8 are connected by the M30 locking ring, and the aperture sleeve 8 is fixed to the side mounting bracket 22.
[0045] In one embodiment, a beam splitter 9 is also provided on the main receiving optical path after the bandpass filter 10. The beam splitter 9 is fixed to the prism frame by a lens sleeve 8, and the prism frame is also used to fix the subsequent dark box 5 and polarizer 11 (not shown in the figure).
[0046] In one embodiment, the beam splitter 9 splits a first beam and a second beam perpendicularly. The first beam is split by an optical meter mounted on a second mounting hole 52 in the successor cassette 5 to measure the number of beam molecules, and the resulting second beam is emitted onto a device in the main receiving optical path. In this embodiment, the second beam is emitted onto a polarizer 11. The second mounting hole 52 is located on the side of the successor cassette 5 away from the mounting housing, thereby enabling the installation of the optical meter while miniaturizing the receiving unit.
[0047] In one embodiment, the polarizer 11 is disposed inside the mounting box 12. One end of the mounting box 12 receives the second beam splitter that has passed through the bandpass filter 10 and emits it onto the polarizer 11. The polarizer 11 polarizes the second beam splitter into a first polarized beam and a second polarized beam. The first polarized beam is detected by a first analog detector installed at the position of the third mounting hole 121 of the mounting box 12, and the second polarized beam is emitted into the device after receiving the main optical path.
[0048] In one embodiment, a converging lens 20 is further disposed on the receiving main optical path, the converging lens 20 being used to converge the second polarized beam. The detection assembly further includes a second analog detector, the second analog detector being disposed at the position of the second beam split off from the converging lens 20, and the second analog detector being disposed on the receiving main optical path.
[0049] In one embodiment, the successor cassette 5 is provided with a first mounting hole 51 on the outer surface of the second reflector 7 for observing whether the direction of light is correct.
[0050] This application is based on the Mie scattering lidar, which is constructed by adding a polarization polarization element and a polarization analysis element to the receiving optical path.
[0051] Based on the structure of the receiving unit described above, for example, when the radar receives the echo light signal corresponding to the 532nm laser emitted by the laser, it first passes through the window, then through the cemented lens 1, and the echo light signal enters the subsequent dark box 5 part, and then passes through the first reflector and the second reflector, the pinhole aperture, and the beam splitter 9.
[0052] The converging lens 20 splits the light beam into a first beam and a second beam. The first beam is detected by a first detector, and the second beam is detected by a second detector. This arrangement of the echo optical path allows for the miniaturization of the receiving unit.
[0053] Based on the above inventive concept, this application also discloses a lidar system, which includes a lidar receiving unit of any of the above embodiments and a laser for emitting a laser beam.
[0054] In this specification, references to terms such as "some embodiments" or "examples" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. The illustrative expressions of the above terms in this specification 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. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.
[0055] The above are merely preferred embodiments of this utility model and do not constitute any limitation on this utility model. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and contents disclosed in this utility model without departing from the scope of the technical solutions of this utility model shall still fall within the protection scope of this utility model.
Claims
1. A lidar receiving unit, characterized in that, include: Cemented lenses are used to focus the light beam entering a telescope; A reflector assembly, comprising multiple reflectors, is used to direct a focused light beam into a receiving optical path assembly; A receiving optical path assembly is disposed in the telescope space between the cemented lens and the mirror assembly. The receiving optical path assembly is used to receive the light beam reflected by the mirror assembly. The receiving optical path assembly is arranged in a direction parallel to the central axis of the telescope and facing the telescope entrance to form a main receiving optical path. A polarizer is disposed on the main receiving optical path. The detection assembly includes a first analog detector positioned along the polarization direction of the polarizer and away from the cemented lens, for receiving a beam of polarized light in one of the two perpendicular polarization directions of the polarizer.
2. The lidar receiving unit according to claim 1, characterized in that, The reflector assembly includes a first reflector and a second reflector arranged sequentially along the optical path; the first reflector reflects the light beam focused by the cemented lens onto the second reflector.
3. A lidar receiving unit according to claim 1, characterized in that, The receiving optical path assembly includes a small aperture stop disposed at the position where the second reflector reflects the light beam.
4. A lidar receiving unit according to claim 3, characterized in that, A plano-convex lens is also provided behind the pinhole aperture, and the plano-convex lens is a hard-film bandpass filter.
5. A lidar receiving unit according to claim 1, characterized in that, This includes a window on the telescope's input port, on which an anti-reflective coating is attached.
6. A lidar receiving unit according to claim 5, characterized in that, It also includes a follow-up dark box, which has a first mounting hole on the outer surface of the second reflector.
7. A lidar receiving unit according to claim 4, characterized in that, A beam splitter is also provided on the receiving main optical path behind the plano-convex lens. The beam splitter splits a first beam splitter and a second beam splitter vertically. The first beam splitter measures the number of beam molecules by an optical meter installed on the second mounting hole of the subsequent dark box, and the second beam splitter is emitted to the device on the receiving main optical path.
8. A lidar receiving unit according to claim 7, characterized in that, The polarizer is disposed in the mounting box. One end of the mounting box receives the second beam that has passed through the bandpass filter and emits it onto the polarizer. The polarizer polarizes the second beam into a first polarized beam and a second polarized beam. The first polarized beam is detected by a first analog detector, and the second polarized beam is emitted into the device after receiving the main optical path. A converging lens is also provided on the main receiving optical path, which is used to converge the second polarized beam; the detection component also includes a second analog detector, which is located at the position of the second beam split off by the converging lens and is located on the main receiving optical path.
9. A lidar receiving unit according to claim 4, characterized in that, The pinhole aperture is disposed inside the sleeve assembly, which is fixed to the side mounting bracket. A partition plate for blocking stray light is disposed in the gap between the side mounting bracket and the telescope housing.
10. A lidar system, characterized in that, The device includes a lidar receiving unit as described in any one of claims 1-9, and further includes a laser for emitting a laser beam.