Area array scanning lidar transmission system based on MEMS galvanometer

Abstract

The present application discloses a MEMS galvanometer-based area array scanning laser radar transmission system, which relates to the field of laser radar technology; the system comprises: a laser for emitting a laser beam; a laser collimator for collimating the beam; a beam splitter, located on a side of the laser collimator away from the laser, for splitting the collimated beam into a first beam and a second beam; a detector, located on a side of the beam splitter, for receiving the second beam and recording the receiving time; a diffraction spectrometer, located on a side of the beam splitter away from the laser, for receiving the first beam and splitting the first beam into an N×N laser dot matrix, where N is greater than or equal to 2; a MEMS galvanometer, located on a side of the diffraction spectrometer away from the beam splitter, for reflecting the laser dot matrix and adjusting the reflection direction of the laser dot matrix; and a lens, located on a side of the MEMS galvanometer away from the laser, for adjusting the working distance of the transmission system and allowing the reflected laser dot matrix to be emitted to the surface of the target to be measured.

Description

Technical Field

[0001] The present invention relates to the field of laser radar technology, and more specifically, to a MEMS galvanometer-based area array scanning laser radar transmission system. Background Art

[0002] LiDAR (LiDAR) is a technology that uses the high directivity of lasers, using laser pulses as carrier waves to detect distant targets and obtain target information through the return signal. Since its emergence, LiDAR technology has demonstrated significant advantages in high-precision and high-speed detection, making it a hot research area.

[0003] LiDAR is essentially laser ranging, and its ranging methods can be categorized into four types: time-of-flight (TOF), phase measurement, interferometry, and triangulation. Each method has varying ranges, accuracy, and applications. Currently, TOF is the most commonly used ranging method in LiDAR, due to its mature development, simple principle, and stable performance.

[0004] In addition, LiDAR can be divided into two types according to the detection method: scanning and non-scanning. Among them, the scanning type uses a single-point laser beam to use a scanning mirror or mechanical structure to complete the three-dimensional detection of the entire object. This detection method has high accuracy and a long range, but it has high requirements for scanning devices and slow sampling speed, which restricts its application. The scanning mirror is the core component of the scanning type. The commonly used optical scanning mirrors are large in size and power consumption, and have great limitations in practical applications. At present, with the development of micro-electromechanical system (MEMS) technology, MEMS scanning mirrors are small in size, light in weight, and highly integrated, and have become a common scanning method for current three-dimensional imaging LiDARs. Although MEMS has increased the scanning speed of scanning LiDARs, there is still room for improvement in their scanning time.

[0005] Non-scanning lidar uses a completely different approach. It uses a dot-matrix laser beam to cover the target. An avalanche photodiode (APD) receives the reflected laser beam and measures the flight time of each dot to determine the target's surface distance. Non-scanning lidar has evolved into flash lidar, with the dot-matrix beam size gradually increasing from 8×8 to 128×128, resulting in higher accuracy and stronger anti-interference capabilities. However, the limited detection angle of non-scanning lidar has hampered its development.

[0006] In the prior art, CN207623628U discloses a collimation system and laser radar based on a MEMS galvanometer, comprising: a laser emitting unit for emitting a modulated laser beam; a front beam shaping unit for shaping the laser emitted by the laser emitting unit; a MEMS galvanometer scanning unit for performing field-of-view scanning on the plane of the object to be measured after resonant reflection of the beam shaped by the front beam shaping unit using a MEMS galvanometer; and a rear collimation unit for performing secondary shaping on the beam reflected by the MEMS galvanometer scanning unit, so that the edge beam and the center beam deflected by the MEMS galvanometer have equal optical path lengths at the entrance pupil of the rear collimation unit. Obviously, the content disclosed in CN207623628U does not involve a diffraction spectrometer. It can be seen that what is disclosed in CN207623628U is still a point scanning process, that is, it only includes the use of a scanning laser radar, and its scanning time still has room for improvement. Summary of the Invention

[0007] In view of this, the present invention provides a MEMS galvanometer-based area array scanning laser radar transmission system to reduce scanning time and increase detection angle, thereby improving the scanning accuracy and scanning speed of the laser radar.

[0008] In a first aspect, the present application provides a MEMS galvanometer-based area array scanning laser radar transmission system, comprising:

[0009] A laser, for generating and emitting a laser beam;

[0010] A laser collimator, located on the light-emitting side of the laser, for collimating the laser beam;

[0011] A beam splitter is located on a side of the laser collimator away from the laser, and is used to split the collimated laser beam into a first beam and a second beam, wherein an extension direction of the first beam intersects an extension direction of the second beam;

[0012] a detector, located on a side of the beam splitter away from the laser collimator, for receiving the second light beam and for recording a time when the second light beam is received;

[0013] a diffraction beam splitter element, located on a side of the beam splitter away from the laser collimator and with a space between the beam splitter and the detector, for receiving the first light beam and splitting the first light beam into an N×N laser dot matrix to form a planar array structure, where N ≥ 2 and N is a positive integer;

[0014] a MEMS galvanometer, located on a side of the diffraction beam splitter away from the beam splitter, for reflecting the planar array structure formed by the N×N laser dot matrix and adjusting a reflection direction of the planar array structure formed by the N×N laser dot matrix;

[0015] A lens is located on a side of the MEMS galvanometer away from the diffraction beam splitter, and is used to adjust the working distance of the emission system and to allow the area array structure formed by the reflected N×N laser dot matrix to be emitted to the surface of the target to be measured;

[0016] The diffraction spectrometer element adopts a Dammann grating, and the diameter of the first light beam irradiated on the Dammann grating is P, where P is ≥ 2.78 mm.

[0017] Optionally, where:

[0018] The laser collimator adopts an adjustable aspheric optical fiber collimator.

[0019] Optionally, where:

[0020] The laser dot matrix is a 64×64 laser dot matrix.

[0021] Optionally, where:

[0022] The lens includes a converging lens.

[0023] Optionally, where:

[0024] The MEMS galvanometer is a dual-axis galvanometer, and the dual-axis scanning angle of the dual-axis galvanometer ranges from ±1.15°.

[0025] Optionally, where:

[0026] The laser is a Q-switched laser;

[0027] Wherein, the output power of the laser is W1, 500mW≤W1≤1500mW.

[0028] Optionally, where:

[0029] The diameter of the laser beam emitted by the laser is R1, 1mm≤R1≤2mm.

[0030] Optionally, where:

[0031] The diameter of the laser beam after the collimation process is R2, 1mm≤R2≤4mm.

[0032] Compared with the prior art, the MEMS galvanometer-based area array scanning laser radar transmission system provided by the present invention achieves at least the following beneficial effects:

[0033] The present application provides a MEMS galvanometer-based area array scanning laser radar transmission system, wherein the diffraction spectrometer element will split the received first light beam into N×N laser dot arrays (area array blocks), and then irradiate the beam to the MEMS galvanometer, completing the scanning process with the vibration of the galvanometer; wherein, the use of the MEMS galvanometer belongs to the use of scanning laser radar, and the area array scanning belongs to the use of non-scanning laser radar; that is, the present application achieves high-precision detection of the target to be measured by combining the scanning laser radar and the non-scanning laser radar, while also improving the scanning accuracy and scanning speed of the laser radar.

[0034] Of course, any product implementing the present invention does not necessarily need to achieve all of the technical effects described above at the same time.

[0035] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0037] Figure 1 Shown is a schematic diagram of a laser radar transmission system provided in an embodiment of the present application;

[0038] Figure 2 Shown is a simulation diagram of the laser radar transmission system provided in an embodiment of the present application;

[0039] Figure 3 Shown is a model diagram of the laser radar transmission system provided in an embodiment of the present application;

[0040] Figure 4 The figure shows a simulation diagram of the effect of a laser beam irradiating a target in a laser radar transmitting system provided in an embodiment of the present application;

[0041] Figure 5 The figure shows the energy distribution diagram of the cross section of the target column illuminated by the laser beam in the laser radar transmission system provided by the embodiment of the present application;

[0042] Figure 6 The figure shows the energy distribution diagram of the cross-section of the target line illuminated by the laser beam in the laser radar transmission system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention.

[0044] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0045] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0046] In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0047] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0048] In the existing technology, LiDAR can be divided into two types according to the detection method: scanning and non-scanning. Among them, the scanning type uses a single-point laser beam to use a scanning mirror or a mechanical structure to complete the three-dimensional detection of the entire object. This detection method has high accuracy and a long range, but it has high requirements for the scanning device and slow sampling speed, which restricts its application. The scanning mirror is the core component of the scanning type. The commonly used optical scanning mirror has a large size and power consumption, which has great limitations in practical applications. At present, with the development of micro-electromechanical system (MEMS) technology, MEMS scanning mirrors are small in size, light in weight, and highly integrated, and have become a common scanning method for current three-dimensional imaging LiDARs. Although MEMS has improved the scanning speed of scanning LiDARs, its scanning time still has room for improvement.

[0049] Non-scanning lidar uses a completely different approach. It uses a dot-matrix laser beam to cover the target. An avalanche photodiode (APD) receives the reflected laser beam and measures the flight time of each dot to determine the target's surface distance. Non-scanning lidar has evolved into flash lidar, with the dot-matrix beam size gradually increasing from 8×8 to 128×128, resulting in higher accuracy and stronger anti-interference capabilities. However, the limited detection angle of non-scanning lidar has hampered its development.

[0050] In view of this, the present invention provides a MEMS galvanometer-based area array scanning laser radar transmission system to reduce scanning time and increase detection angle, thereby improving the scanning accuracy and scanning speed of the laser radar.

[0051] Figure 1FIG. 1 is a schematic diagram of a laser radar transmitting system provided in an embodiment of the present application. Figure 2 The figure shows a simulation diagram of the laser radar transmitting system provided in the embodiment of the present application. Figure 1 and Figure 2 The present application provides a planar array scanning laser radar transmission system 100 based on a MEMS galvanometer 15, comprising:

[0052] A laser 11, configured to generate and emit a laser beam;

[0053] The laser collimator 12 is located on the light-emitting side of the laser 11 and is used to collimate the laser beam;

[0054] The beam splitter 13 is located on the side of the laser collimator 12 away from the laser 11 and is used to split the collimated laser beam into a first beam 131 and a second beam 132, where the extension direction of the first beam intersects with the extension direction of the second beam;

[0055] The detector 18 is located on a side of the beam splitter 13 away from the laser collimator 12, and is used to receive the second light beam 132 and record the time when the second light beam 132 is received;

[0056] The diffraction beam splitter element 14 is located on a side of the beam splitter 13 away from the laser collimator 12 and includes a space between the beam splitter 13 and the detector 18, and is used to receive the first light beam 131 and split the first light beam 131 into an N×N laser dot array to form a planar array structure, where N ≥ 2 and N is a positive integer;

[0057] The MEMS galvanometer 15 is located on the side of the diffraction beam splitter 14 away from the beam splitter 13 and is used to reflect the surface array structure formed by the N×N laser dot array and to adjust the reflection direction of the surface array structure formed by the N×N laser dot array;

[0058] The lens 16 is located on the side of the MEMS galvanometer 15 away from the diffraction beam splitter 14 and is used to adjust the working distance of the transmitting system 100 and to make the surface array structure formed by the reflected N×N laser dot matrix be emitted to the surface of the target 17 to be measured;

[0059] The diffraction spectrometer uses a Dammann grating, and the diameter of the first light beam irradiated on the Dammann grating is P, where P is ≥ 2.78 mm.

[0060] Specifically, the present application provides a surface array scanning laser radar transmitting system 100 of a MEMS galvanometer 15, wherein the laser radar transmitting system 100 includes a laser 11, a laser collimator 12, a beam splitter 13, a detector 18, a diffraction spectrometer 14, a MEMS galvanometer 15 and a lens 16; wherein the laser 11 is used to generate a laser beam and emit the laser beam to one side of the laser collimator 12, specifically, the laser beam can be connected to the laser collimator 12 through an optical fiber; then, the laser collimator 12 will collimate the received laser beam, which can be used to reduce the divergence angle of the laser beam; then, the collimated laser beam will be emitted to the beam splitter 13, and the beam splitter 13 is used to split the collimated laser beam into two, namely, a first beam 131 and a second beam 132, wherein the extension direction of the first beam and the extension direction of the second beam are different; then, the second beam 132 will be emitted to one side of the detector 18, the The second light beam 132 can be used as a reference signal, that is, the detector 18 records the receiving time when receiving the second light beam 132. This time can be used as the time point when the laser beam starts to be emitted, and can be used for subsequent detection of the distance between the transmitting system 100 and the target 17 to be measured; the first light beam 131 will be emitted to one side of the diffraction spectrometer 14, and the diffraction spectrometer 14 is used to split the first light beam 131 into an N×N laser dot matrix, that is, to split the first light beam 131 into a surface array block (surface array structure), and the N×N laser dot matrix will then be emitted to the MEMS galvanometer 15, and the MEMS galvanometer 15 is used to reflect the surface array structure formed by the received N×N laser dot matrix, and the MEMS galvanometer 15 can vibrate according to needs, thereby adjusting the specific reflection direction of the N×N laser dot matrix, so that the laser reflected by the MEMS galvanometer 15 can be evenly emitted to the entire surface of the target 17 to be measured, avoiding the problem of the laser only being emitted to part of the surface of the target 17 to be measured. It should also be added that a lens 16 is provided between the MEMS galvanometer 15 and the target 17 to be measured. The lens 16 can be used to adjust the working distance of the emission system 100 so that the laser beam spot can be dispersed after passing through the lens 16 and fall on the surface of the target 17 to be measured. Figure 2 As shown, the laser beam after collimation and splitting is irradiated onto the diffraction splitter element 14 and split into a 64×64 laser dot matrix, which is then reflected by the MEMS galvanometer 15 and completes the scanning process following the swing of the MEMS galvanometer 15.

[0061] The use of the MEMS galvanometer 15 proposed in this application is a scanning laser radar, and the diffraction spectrometer 14 splits the laser beam into a 64×64 laser dot array (area array block), which is a non-scanning laser radar. Since scanning laser radars have the advantage of fast scanning speed, and non-scanning laser radars have the advantages of high precision and fast imaging speed, compared to conventional technologies that use only scanning laser radars or only non-scanning laser radars, this application combines the advantages of scanning laser radars and non-scanning laser radars to achieve high-precision detection of the target 17 to be measured, while also improving the scanning accuracy and scanning speed of the laser radar.

[0062] The detector 18 may be an APD detector 18 , wherein the second light beam 132 irradiating the APD detector 18 may serve as a timing start signal for the laser beam to be emitted.

[0063] The present application provides an optional setting method, in which the diffraction spectrometer 14 adopts a Dammann grating, the working wavelength is 1064nm, the splitting ratio is 64×64, the minimum beam diameter is 2.78mm, the beam separation angle is 0.13°×0.13°, and the field of view angle is 8.31°×8.31°. Considering that the divergence angle of the collimated laser passing through the laser collimator 12 is 0.032°, a 64×64 laser dot matrix with a duty cycle of 4:1 is finally generated.

[0064] It should be added that the design of the Dammann grating is related to the wavelength, and a specific value is generally taken for design. The overall wavelength range of the Dammann grating is between 180nm-11um. Among them, the Dammann grating requires the minimum diameter of the incident laser beam to be 2.78mm. If it is smaller than this diameter, it may affect the spectroscopic effect. Among them, the beam separation angle and field angle of the Dammann grating are limited by the design of the Dammann grating. The beam separation angle generally ranges from 0.3° to 0.05°, and the field angle generally ranges from 1° to 15°. Among them, the divergence angle of the laser collimator 12 is the result of the collimation of the laser collimator 12, and it may not take a fixed value (the aforementioned 0.032°), as long as the value is smaller than the separation angle.

[0065] In this application, the higher the splitting ratio of the diffraction spectrometer element 14, the greater the manufacturing difficulty, the higher the detection accuracy, and the more requirements on the quality and diameter of the laser beam. If other splitting ratios are used, it is necessary to reasonably consider the laser quality and the obtained laser dot array separation angle and field of view angle.

[0066] Please refer to Figure 1 Optionally, the laser collimator 12 is an adjustable aspheric fiber collimator. Optionally, the diameter of the laser beam after collimation is R2, 1mm≤R2≤4mm.

[0067] Specifically, the present application provides an optional setting method in which the laser collimator 12 adopts an adjustable aspheric fiber collimator with an operating wavelength of 1064nm, an output beam diameter of 1mm-4mm, and a beam divergence angle of 0.032°.

[0068] It should be added that the adjustable aspheric fiber collimator here can also be replaced by an ordinary fiber collimator, as long as the wavelength is guaranteed to be consistent and the beam diameter and beam divergence angle meet the requirements; this application does not limit the above-mentioned adjustable aspheric fiber collimator as the laser collimator 12.

[0069] Other devices that can collimate the laser beam, such as the plano-convex lens 16 and the lens group 16, need to consider both the divergence angle and the beam diameter after collimation, and are difficult to meet the collimation requirements.

[0070] Please refer to Figure 1 Optionally, the laser dot matrix is a 64×64 laser dot matrix.

[0071] Specifically, the present application provides an optional embodiment in which the diffraction beam splitting element 14 can split the first light beam 131 into a 64×64 laser dot matrix. It should be noted that the 64×64 laser dot matrix is only one of the optional N×N values provided by the present application, but is not limited to this. Users can adjust the specific N×N value according to actual needs.

[0072] It should also be added that a large splitting ratio can improve the scanning accuracy of the laser radar, but it will also be more difficult to manufacture; in addition to the specific value of the N×N laser dot matrix provided above, which is 64×64 laser dot matrix, other values can actually be taken, such as 5×5, or 19×19, or 32×32, etc.; however, if a larger splitting ratio than 64×64 is taken, there may be a problem that the size of other devices in the laser radar transmitting system 100 does not meet the requirements; among them, the main component limiting the large splitting ratio is the MEMS galvanometer 15, specifically the size of the MEMS galvanometer.

[0073] Please refer to Figure 1 Optionally, the lens 16 includes a converging lens 16 .

[0074] Specifically, a converging lens 16 with a suitable focal length may be selected according to the distance to the detection target. The converging lens 16 may be a lens 16 with a converging function, such as a convex lens 16 .

[0075] Figure 3 The figure shows the model diagram of the laser radar transmitting system provided in the embodiment of the present application. Figure 1 Reference Figure 3 Optionally, the MEMS galvanometer 15 is a dual-axis galvanometer, and the dual-axis scanning angle of the dual-axis galvanometer is ±1.15°.

[0076] Specifically, the MEMS galvanometer 15 can be a dual-axis galvanometer, such as Figure 3 As shown, it can swing in two axis directions perpendicular to the propagation direction of the light beam and can be driven by electromagnetic force. The dual-axis scanning angle of the dual-axis galvanometer is ±1.15°, the mirror diameter (light-clearing aperture) is 7.5mm, and the vibration frequency is 100Hz~1000Hz, which meets the laser beam size requirements after beam splitting.

[0077] The MEMS galvanometer 15 can swing within a preset deflection angle to form a scanning beam, and finally completes the scanning of the target 17 through the lens 16. The dual-axis scanning angle of ±1.15° provided above is only an optional embodiment provided by the present application. Different scanning angles can be selected for MEMS galvanometers of different sizes, such as ±3°, ±4.5°, ±7.5°, etc., and the present application does not make specific limitations on this.

[0078] In this application, the MEMS galvanometer 15 (also referred to as a MEMS micromirror) refers to an optical MEMS device that is manufactured using an optical micro-electro-mechanical system 100 (MEMS) manufacturing process and integrates a micro-light reflector and a MEMS driver.

[0079] It should be added that MEMS has electrostatic, electromagnetic, piezoelectric, electrothermal and other driving modes, each with its own advantages and disadvantages. Other driving modes besides electromagnetic driving can also be selected to meet the size requirements. This application does not make specific restrictions on this.

[0080] It should also be added that the greater the vibration frequency, the better the scanning effect; however, a large vibration frequency is not easy to manufacture; the vibration frequency here is 100Hz~1000Hz, which is the range of 7.5mmMEMS, and a vibration frequency that is too small will affect the scanning effect.

[0081] In addition, if other models of MEMS galvanometers are selected, the trade-off between the mirror's aperture, scanning angle, and vibration frequency must be carefully considered. Generally speaking, the larger the mirror's aperture, the lower the scanning angle and the lower the vibration frequency. However, a mirror with an aperture that is too small can affect the overall structure and even prevent the laser beam from being fully received.

[0082] Please refer to Figure 1 , optionally, the laser 11 is a Q-switched laser 11;

[0083] The output power of the laser 11 is W1, 500 mW≤W1≤1500 mW.

[0084] Specifically, the laser 11 can be a Q-switched laser 11, specifically a Q-switched pulsed laser 11, with an adjustable output laser pulse power within a range of 500mW to 1500mW and a wavelength of 1064nm. Optionally, the diameter of the laser beam emitted by the laser 11 is R1, where 1mm≤R1≤2mm. The output laser beam diameter can be 1.5mm, and the laser beam divergence angle is 0.1°.

[0085] It should be noted that Q refers to the quality factor of the laser 11 resonant cavity. The Q value can be changed by changing the loss in the cavity to obtain a high-peak, narrow-pulse-width pulse laser. This application uses this laser 11 to ensure that the laser intensity after beam splitting is sufficient.

[0086] It should also be noted that the output power W1 of the laser 11 proposed in this application ranges from 500mW to 1500mW. This is merely one optional embodiment provided by this application and is not intended to be limiting. While theoretically, a higher laser power is better, high-power lasers 11 are more difficult to manufacture and may be harmful to the human eye when used on land. Too little power can affect subsequent laser beam splitting, and too low a power of the split laser beam can affect the scanning effect.

[0087] It should also be noted that the 1064nm laser wavelength proposed in this application is selected in conjunction with the Dammann grating; this application does not limit the value range of this laser wavelength, and the value depends on the operating wavelength of the Dammann grating and the operating wavelength of the detector 18.

[0088] It should also be noted that the diameter of the laser beam is 1mm-2mm, which is an optional value range provided by this application. A value that is too low will affect the laser power, and a value that is too high will affect the coordination with subsequent components.

[0089] It should also be noted that the laser beam divergence angle of 0.1° is an optional value provided in this application, but is not limited to this. This divergence angle depends on the performance of the laser 11. Generally speaking, the smaller the better. The value here can be less than 1.5 mrad.

[0090] That is, as long as the wavelength, power, and beam diameter are appropriate, the laser 11 can be selected arbitrarily; after the laser is emitted, it is transmitted by optical fiber and then transmitted to the laser collimator 12 for collimation.

[0091] Alternatively, the beam splitter 13 may be a common prism beam splitter 13 or other device with light splitting capability, which is not specifically limited in the present application.

[0092] Figure 4 The figure shows a simulation diagram of the effect of a laser beam irradiating a target in a laser radar transmitting system provided in an embodiment of the present application. Figure 5The figure shows the energy distribution diagram of the cross section of the target column illuminated by the laser beam in the laser radar transmission system provided by the embodiment of the present application. Figure 6 The figure shows the energy distribution diagram of the target line cross section of the laser beam irradiated in the laser radar transmitting system provided by the embodiment of the present application. Figure 1 Reference Figure 4-Figure 6 It should be added that Figure 4 The incoherent irradiance is a process in which the blackness gradually increases from 0 to 41.7.

[0093] Attachment Figure 4 The image shows the distribution of the laser dot matrix on a simulated target. The horizontal and vertical axes represent the x-axis and y-axis coordinates on the simulated image plane, respectively. The darkness of the dots represents the incoherent irradiance of the laser dot matrix. It can be seen that after diffraction and reflection from the MEMS galvanometer 15, the laser dot matrix produces a clear and uniform image.

[0094] Attachment Figure 5 , Attachment Figure 6 This image shows the energy distribution of the laser lattice on the target. The horizontal axis represents the row and column cross-section coordinates, with the laser lattice diffraction center as the zero point. The vertical axis represents the incoherent irradiance. Simulation results show that the scanning lattice produced by the laser scanning device of the present invention has a uniformity of greater than 90%.

[0095] The laser radar transmitting system 100 provided in the present application has high laser dot array uniformity, which can greatly improve the scanning accuracy, scanning speed and detection resolution of the laser radar during the block scanning process.

[0096] It can be seen from the above embodiments that the MEMS galvanometer-based area array scanning laser radar transmission system provided by the present invention achieves at least the following beneficial effects:

[0097] The present application provides a MEMS galvanometer-based area array scanning laser radar transmission system, wherein the diffraction spectrometer element will split the received first light beam into N×N laser dot arrays (area array blocks), and then irradiate the beam to the MEMS galvanometer, completing the scanning process with the vibration of the galvanometer; wherein, the use of the MEMS galvanometer belongs to the use of scanning laser radar, and the area array scanning belongs to the use of non-scanning laser radar; that is, the present application achieves high-precision detection of the target to be measured by combining the scanning laser radar and the non-scanning laser radar, while also improving the scanning accuracy and scanning speed of the laser radar.

[0098] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should be understood by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A MEMS galvanometer-based area array scanning laser radar transmission system, characterized in that: include: A laser, for generating and emitting a laser beam; A laser collimator, located on the light-emitting side of the laser, is used to collimate the laser beam. The laser collimator adopts an adjustable aspheric fiber collimator; A beam splitter is located on a side of the laser collimator away from the laser, and is used to split the collimated laser beam into a first beam and a second beam, wherein an extension direction of the first beam intersects an extension direction of the second beam; a detector, located on a side of the beam splitter away from the laser collimator, for receiving the second light beam and for recording a time when the second light beam is received, wherein the detector is an APD detector; a diffraction beam splitting element, located on a side of the beam splitter away from the laser collimator and with a space between the beam splitter and the detector, for receiving the first light beam and splitting the first light beam into an N×N laser dot matrix to form a planar array structure, where N ≥ 2 and N is a positive integer; a MEMS galvanometer, located on a side of the diffraction beam splitter away from the beam splitter, for reflecting the planar array structure formed by the N×N laser dot matrix and adjusting a reflection direction of the planar array structure formed by the N×N laser dot matrix; A lens is located on a side of the MEMS galvanometer away from the diffraction beam splitter element, and is used to adjust the working distance of the emission system and to allow the area array structure formed by the reflected N×N laser dot matrix to be emitted to the surface of the target to be measured; The diffraction spectrometer element adopts a Dammann grating, and the diameter of the first light beam irradiated on the Dammann grating is P, where P is ≥ 2.78 mm.

2. The MEMS galvanometer-based area array scanning laser radar transmitting system according to claim 1 is characterized in that: The laser dot matrix is a 64×64 laser dot matrix.

3. The MEMS galvanometer-based area array scanning laser radar transmitting system according to claim 1, characterized in that: The lens includes a converging lens.

4. The MEMS galvanometer-based area array scanning laser radar transmitting system according to claim 1, characterized in that: The MEMS galvanometer is a dual-axis galvanometer, and the dual-axis scanning angle of the dual-axis galvanometer ranges from ±1.15°.

5. The MEMS galvanometer-based area array scanning laser radar transmitting system according to claim 1, characterized in that: The laser is a Q-switched laser; Wherein, the output power of the laser is W1, 500mW≤W1≤1500mW.

6. The MEMS galvanometer-based area array scanning laser radar transmitting system according to claim 1, characterized in that: The diameter of the laser beam emitted by the laser is R1, 1mm≤R1≤2mm.

7. The MEMS galvanometer-based area array scanning laser radar transmitting system according to claim 1, characterized in that: The diameter of the laser beam after the collimation process is R2, 1mm≤R2≤4mm.

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