Laser radar device

Abstract

The invention relates to the technical field of laser radars, in particular to a laser radar device. According to the invention, through the collaborative design of integrating the dual-wavelength coherent detection loop, the double galvanometers and the rotating mirror, the field angle is flexibly and dynamically adjusted. Specifically, by adjusting the relative positions and angles of the first galvanometer, the second galvanometer and the rotating mirror, the overlap ratio of the scanning range of the signal light with the two wavelengths can be changed, so that the field angle can be adaptively switched in different application scenes, the coverage area can be expanded when large-range detection is needed, and high-density point cloud scanning can be realized when a local area is concerned. Therefore, the environmental adaptability and detection efficiency of the laser radar are remarkably improved, the detection range and precision are considered, meanwhile, the system integration degree and reliability are enhanced through optical structure multiplexing, and the laser radar is suitable for the multi-scene requirements of automatic driving, robot navigation and the like.

Description

Technical Field

[0001] This invention relates to the field of lidar technology, and more specifically to a lidar device. Background Technology

[0002] Frequency Modulated Continuous Wave (FMCW) lidar is widely used in fields such as roads, warehouse storage, and drone patrols. The core requirements for FMCW lidar vary significantly depending on the application scenario. For example, some scenarios require it to have a large field of view (FOV) to quickly detect large-area spatial information, while other scenarios require it to accurately identify local areas.

[0003] In existing technologies, most common FMCW lidars are semi-solid-state rotating mirror lidars with galvanometers. On the one hand, the polyhedral rotating mirror structure is large in size, occupying the effective space inside the lidar. Only one face of the polyhedral rotating mirror is used at the same time, resulting in low utilization efficiency. On the other hand, due to the fixed field of view design, it cannot dynamically adjust the field of view according to the scene, making it difficult to simultaneously meet the dual requirements of "large-area detection" and "local accurate recognition", and it has significant limitations in multi-scene adaptability. Summary of the Invention

[0004] In view of this, the present invention provides a lidar device to solve the technical problem that lidar in the prior art has significant limitations in its ability to adapt to multiple scenarios.

[0005] The technical solution provided by this invention is as follows:

[0006] The first aspect of the present invention provides a lidar device, the device comprising: a first wavelength coherent detection circuit, a second wavelength coherent detection circuit, a first galvanometer, a second galvanometer, and a rotating mirror; The first wavelength coherent detection circuit is used to split the first wavelength optical signal into a first wavelength reference light and a first wavelength signal light, and input the first wavelength signal light to the first galvanometer. The second wavelength coherent detection circuit is used to split the second wavelength optical signal into a second wavelength reference light and a second wavelength signal light, and input the second wavelength signal light to the second galvanometer. The first galvanometer is used to illuminate the first wavelength signal light onto the first surface of the rotating mirror; The second galvanometer is used to illuminate the second wavelength signal light onto the second surface of the rotating mirror; The rotating mirror illuminates the first wavelength signal light and the second wavelength signal light onto the same target object, and receives the first wavelength signal light and the second wavelength signal light reflected by the target object. After the reflected first wavelength signal light and the second wavelength signal light pass through the first galvanometer and the second galvanometer respectively, the reflected first wavelength signal light enters the first wavelength coherent detection circuit and the first wavelength reference light for coherent detection, and the reflected second wavelength signal light enters the second wavelength coherent detection circuit and the second wavelength reference light for coherent detection. When the lidar device is applied to different scenarios, the positions and angles of the first galvanometer, the second galvanometer, and the rotating mirror are different, so that the overlap of the scanning ranges of the first wavelength signal light and the second wavelength signal light is different, and the field of view of the lidar device is different.

[0007] This invention achieves flexible and dynamic adjustment of the field of view by integrating a dual-wavelength coherent detection circuit, dual galvanometers, and a rotating mirror. Specifically, by adjusting the relative positions and angles of the first galvanometer, the second galvanometer, and the rotating mirror, the overlap of the scanning ranges of the two wavelength signal lights can be changed, thereby adaptively switching the field of view in different application scenarios. This allows for expanding the coverage area when large-scale detection is needed, and achieving high-density point cloud scanning when focusing on local areas. This significantly improves the environmental adaptability and detection efficiency of the lidar, balancing detection range and accuracy. Furthermore, the reuse of optical structures enhances system integration and reliability, making it suitable for various scenarios such as autonomous driving and robot navigation.

[0008] In one alternative embodiment, the device further includes: a first rotating shaft, a second rotating shaft, a slide rail, and a control system; The first galvanometer is mounted on the first rotating shaft, the second galvanometer is mounted on the second rotating shaft, and the rotating mirror is mounted on the slide rail; The control system is used to control the swing angle of the first galvanometer and the second galvanometer via the first rotating shaft and the second rotating shaft, change the position of the galvanometer via the slide rail, and change the rotation angle of the galvanometer.

[0009] In this invention, an integrated control system enables coordinated control of the first galvanometer, the second galvanometer, and the rotating mirror. Specifically, the system can precisely control the swing angle of the galvanometer by independently adjusting two rotating axes, while simultaneously using a slide rail to flexibly adjust the spatial position and rotation angle of the rotating mirror. This achieves full-degree-of-freedom dynamic control of the optical path, allowing for precise adjustment of the beam's scanning range, pointing accuracy, and focusing area.

[0010] In one optional implementation, when the application scenario is that the field of view of the lidar device is greater than the field of view of the first threshold, the control system controls the rotating mirror to move towards the first galvanometer and the second galvanometer via the slide rail; When the application scenario is that the field of view of the lidar device is less than the field of view of the second threshold, the control system controls the rotating mirror to move away from the first galvanometer and the second galvanometer via the slide rail; In different scenarios, the control system controls the swing angle of the first galvanometer and the second galvanometer, as well as the rotation angle of the rotating mirror, to achieve point cloud scanning in the X and Y directions.

[0011] In this invention, by dynamically adjusting the spatial position and angle of the galvanometer and the rotating mirror through a control system, the rotating mirror can be automatically controlled to move closer to or further away from the galvanometer assembly according to the required field of view of the application scenario, thereby flexibly adjusting the spatial layout of the scanning optical path. This enables the lidar to achieve wide-coverage detection in scenarios with a large field of view, and to perform localized high-density scanning in scenarios with a small field of view, effectively balancing detection range and point cloud accuracy. Simultaneously, through coordinated control of the galvanometer's swing angle and the rotating mirror's rotation angle, the accuracy and adaptability of point cloud scanning in the X and Y directions are ensured, comprehensively improving the lidar's scanning performance and scene adaptability in different environments.

[0012] In an optional implementation, when the application scenario is that the field of view of the lidar device is less than the field of view of the second threshold, the control system is further configured to control the swing angles of the first galvanometer and the second galvanometer to be different, so that the scanning points of the first wavelength signal light and the second wavelength signal light appear alternately in the Y direction.

[0013] In this invention, the control system causes the first and second galvanometers to swing at different angles, resulting in alternating scanning points of two wavelength signal lights in the Y direction. This effectively increases the density of the point cloud distribution in the vertical direction, especially in applications where the lidar has a small field of view (requiring high-precision local detection), effectively enhancing scanning resolution without increasing the scanning frequency. This helps acquire richer and more continuous surface information of the target area, improving the accuracy of imaging details and contour reconstruction, thereby significantly improving the performance of lidar in tasks such as target recognition and feature extraction for detailed local detection.

[0014] In one alternative implementation, the first wavelength signal light and the second wavelength signal light have different reflectivities on the same target object, and the coherent detection probability of the target object is greater than a third threshold.

[0015] This invention effectively overcomes the detection blind spots of a single wavelength in specific materials or environments by complementing the difference in reflectivity between two wavelengths, significantly improving the system's success rate in detecting complex, low-reflectivity, or highly interference-prone targets and enhancing its identification reliability. This strengthens the adaptability and robustness of lidar in diverse real-world scenarios, enabling it to perform detection tasks more stably and accurately in critical applications such as autonomous driving and target recognition.

[0016] In one optional embodiment, the device further includes: a lidar chip and a scanning system, wherein the first wavelength coherent detection circuit and the second wavelength coherent detection circuit are disposed on the lidar chip, and the first galvanometer, the second galvanometer, and the rotating mirror are disposed in the scanning system; The lidar chip also includes a beam combining module, which is used to combine the first wavelength signal light and the second wavelength signal light to obtain a combined signal and input it to the scanning system. The beam combining module is also used to split the reflected first wavelength signal light and the second wavelength signal light and transmit them to the first wavelength coherent detection circuit and the second wavelength coherent detection circuit respectively. The scanning system further includes a beam splitting module, which is used to split the combined signal into beams, and then illuminate the first wavelength signal light after splitting into beams onto the first galvanometer and the second wavelength signal light after splitting into beams onto the second galvanometer. The beam splitting module is also used to combine the reflected first wavelength signal light and second wavelength signal light and transmit them to the beam combining module.

[0017] In this invention, a highly modular design is achieved by integrating the first and second wavelength coherent detection circuits onto a lidar chip, and placing the first galvanometer, second galvanometer, and rotating mirror within the scanning system. Specifically, the beam combining module on the chip side performs efficient beam combining of the dual-wavelength signals and beam splitting of the echo signals, while the beam splitting module in the scanning system is responsible for precisely distributing and recovering the beam in conjunction with the galvanometers. This collaborative structure effectively reduces optical crosstalk and energy loss, ensuring the stability of signal transmission and processing, thereby significantly improving the overall detection accuracy and reliability of the lidar system, and providing feasibility for system miniaturization and integration.

[0018] In one alternative implementation, the beam combining module includes a wavelength mixer and an optical mode conversion waveguide; The wavelength mixer is used to combine the first wavelength signal light and the second wavelength signal light to obtain a combined signal light; The optical mode conversion waveguide is used to amplify the combined signal light and input it into the scanning system; The optical mode conversion waveguide is also used to transmit the reflected first wavelength signal light and second wavelength signal light to the wavelength mixer; The wavelength mixer is also used to split the reflected first wavelength signal light and the second wavelength signal light into beams.

[0019] In one alternative embodiment, the beam splitting module includes: a collimating lens and a wavelength splitter; The collimating lens is used to collimate the expanded and combined signal light and transmit it to the wavelength splitter. The wavelength splitter is used to split the collimated beam-combined signal into beams that are then directed onto the first and second galvanometers respectively. The wavelength splitter is also used to combine the reflected first wavelength signal light and second wavelength signal light and transmit them to the collimating lens. The collimating lens is also used to transmit the reflected first wavelength signal light and second wavelength signal light to the optical mode conversion waveguide.

[0020] In this invention, the precise and efficient beam combining and splitting of dual-wavelength signals is achieved through the collaborative design of a beam combining module (including a wavelength mixer and an optical mode conversion waveguide) and a beam splitting module (including a collimating mirror and a wavelength splitter), reducing the coupling loss between the integrated chip and free space transmission of optical signals. The mode conversion and collimation process ensures optical field mode matching, improving energy utilization efficiency and signal integrity. At the same time, this modular optical path design enhances the stability and reliability of the system, providing key technical support for the miniaturization and high-precision integration of optical detection systems such as lidar.

[0021] In one optional embodiment, the first wavelength coherent detection loop includes a first optical waveguide coupler, a second optical waveguide coupler, a third optical waveguide coupler, a first balanced detector, and a first incident waveguide; The first input waveguide is used to receive a first wavelength optical signal and transmit the first wavelength optical signal to the second optical waveguide coupler. The second optical waveguide coupler is used to split the first wavelength optical signal into a first wavelength signal light and a first wavelength reference light. The first wavelength reference light is transmitted to the third optical waveguide coupler, and the first wavelength signal light is transmitted to the first optical waveguide coupler. The first optical waveguide coupler is used to output the first wavelength signal light. The first optical waveguide coupler is also used to receive the reflected first wavelength signal light and transmit the reflected first wavelength signal light to the third optical waveguide coupler. The third optical waveguide coupler is used to combine the first wavelength signal light and the first wavelength reference light and transmit them to the first balanced detector for coherent detection.

[0022] In one optional embodiment, the second wavelength coherent detection circuit includes a fourth optical waveguide coupler, a fifth optical waveguide coupler, a sixth optical waveguide coupler, a second balanced detector, and a second input waveguide; The second input waveguide is used to receive a second wavelength optical signal and transmit the second wavelength optical signal to the fifth optical waveguide coupler. The fifth optical waveguide coupler is used to split the second wavelength optical signal into a second wavelength signal light and a second wavelength reference light. The second wavelength reference light is transmitted to the sixth optical waveguide coupler, and the second wavelength signal light is transmitted to the fourth optical waveguide coupler. The fourth optical waveguide coupler is used to output the second wavelength signal light. The fourth optical waveguide coupler is also used to receive the reflected second wavelength signal light and transmit the reflected second wavelength signal light to the sixth optical waveguide coupler. The sixth optical waveguide coupler is used to combine the second wavelength signal light and the second wavelength reference light and transmit them to the second balanced detector for coherent detection.

[0023] This invention achieves precise beam splitting, combining, and coherent detection of the signal and reference beams through a two-wavelength coherent detection loop design. Specifically, this structure improves the stability and efficiency of optical signal transmission and reduces optical path loss; furthermore, by using a balanced detector for coherent detection, it significantly enhances the system's sensitivity and signal-to-noise ratio for weak echo signals; simultaneously, this structure simplifies the optical path layout, enhances the system's reliability and integration, and provides a key technological foundation for achieving high precision and miniaturization in optical detection equipment such as lidar. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a structural block diagram of the lidar device in an embodiment of the present invention; Figure 2 This is a schematic diagram of the operation of the rotating mirror and galvanometer of the lidar device in an embodiment of the present invention; Figure 3 This is a structural block diagram of the lidar chip in the lidar device of the present invention. Figure 4 This is a structural block diagram of the scanning system of the lidar device in an embodiment of the present invention; Figure 5 This is a schematic diagram of a large field-of-view scanning laser radar device in an embodiment of the present invention; Figure 6 This is a schematic diagram of point cloud stitching scanning of the lidar device in an embodiment of the present invention; Figure 7 This is a schematic diagram of point cloud stitching for a lidar device in an embodiment of the present invention. Detailed Implementation

[0026] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] This invention provides a lidar device, such as... Figure 1 As shown, the device includes: a first wavelength coherent detection circuit 21, a second wavelength coherent detection circuit 22, a first galvanometer 14, a second galvanometer 16, and a rotating mirror 13; The first wavelength coherent detection circuit 21 is used to divide the first wavelength optical signal into a first wavelength reference light and a first wavelength signal light, and input the first wavelength signal light to the first galvanometer 14; The second wavelength coherent detection circuit 22 is used to split the second wavelength optical signal into a second wavelength reference light and a second wavelength signal light, and input the second wavelength signal light to the second galvanometer 16; The first galvanometer 14 is used to illuminate the first wavelength signal light onto the first surface of the rotating mirror 13; The second galvanometer 16 is used to illuminate the second wavelength signal light onto the second surface of the rotating mirror 13; The rotating mirror 13 illuminates the first wavelength signal light and the second wavelength signal light onto the same target object, and receives the first wavelength signal light and the second wavelength signal light reflected by the target object. After the reflected first wavelength signal light and the second wavelength signal light pass through the first galvanometer 14 and the second galvanometer 16 respectively, the reflected first wavelength signal light enters the first wavelength coherent detection circuit 21 and the first wavelength reference light for coherent detection, and the reflected second wavelength signal light enters the second wavelength coherent detection circuit 22 and the second wavelength reference light for coherent detection. When the lidar device is applied to different scenarios, the positions and angles of the first galvanometer 14, the second galvanometer 16, and the rotating mirror 13 are different, so that the overlap of the scanning ranges of the first wavelength signal light and the second wavelength signal light is different, and the field of view of the lidar device is different.

[0031] Specifically, to address the varying requirements of lidar in different application scenarios—that is, to use the same lidar device to meet different detection needs in different application scenarios—this embodiment sets up two sets of wavelength coherent detection loops in the lidar device, outputting two signal beams with different wavelengths. It also includes two galvanometers and one rotating mirror. The two galvanometers are symmetrically positioned on either side of the rotating mirror, illuminating the two signal beams onto different surfaces of the rotating mirror, which then reflects the signal beams to the target object. By changing the position and angle of the galvanometers and the rotating mirror, the scanning range of the signal beams can be altered, resulting in different degrees of overlap between the scanning ranges of the two signal beams.

[0032] Specifically, when the lidar device needs a large field of view for rapid detection of large-area spatial information, the scanning range of the signal beams can be adjusted to minimize the overlap between the scanning ranges of the two beams. In this case, the overall scanning range of the two beams is larger, thus achieving a large field of view. When the lidar device needs to accurately identify a local area, the overlapping of the scanning ranges of the two beams can be increased, meaning that both beams simultaneously scan a specific area, thereby achieving accurate identification.

[0033] It should be noted that for the first wavelength coherent detection circuit and the second wavelength coherent detection circuit, a structure capable of coherent detection in related technologies can be adopted, that is, a structure capable of coherently detecting the reflected signal light and the pre-splittered reference light.

[0034] In one optional embodiment, the device further includes: a first rotating shaft, a second rotating shaft, a slide rail, and a control system; the first galvanometer is disposed on the first rotating shaft, the second galvanometer is disposed on the second rotating shaft, and the rotating mirror is disposed on the slide rail; the control system is used to control the swing angle of the first galvanometer and the second galvanometer through the first rotating shaft and the second rotating shaft, change the position of the rotating mirror through the slide rail, and change the rotation angle of the rotating mirror.

[0035] Specifically, to achieve automatic control of the angle and position of the galvanometer and rotating mirror, the lidar device includes a first rotating axis for the first galvanometer, a second rotating axis for the second galvanometer, and a slide rail for the rotating mirror. Controlling the first and second rotating axes allows control of the swing angles of the first and second galvanometers; controlling the slide rail allows control of the rotating mirror; and controlling the rotating mirror itself allows for changing its angle. The control system can incorporate motors to control the first and second rotating axes, the slide rail, and the rotating mirror itself. Therefore, in different application scenarios, only the control system needs to control the first and second rotating axes, the slide rail, and the rotating mirror to meet the application requirements of different scenarios, i.e., dynamically adjusting the field of view according to the scene.

[0036] In one optional implementation, when the application scenario is that the field of view of the lidar device is greater than the first threshold field of view, the control system controls the rotating mirror to move closer to the first galvanometer and the second galvanometer via the slide rail; when the application scenario is that the field of view of the lidar device is less than the second threshold field of view, the control system controls the rotating mirror to move away from the first galvanometer and the second galvanometer via the slide rail.

[0037] Specifically, when the application scenario involves a lidar device with a field of view greater than a first threshold, the control system controls a slide rail to move the rotating mirror closer to the two galvanometers. This results in a larger overlap range between the two signal beams output from the two surfaces of the rotating mirror, achieving a large field of view scanning. Conversely, when the application scenario involves a lidar device with a field of view less than a second threshold, the control system controls a slide rail to move the rotating mirror further away from the two galvanometers. This results in a smaller overlap range between the two signal beams output from the two surfaces of the rotating mirror, achieving a small field of view scanning. The first and second thresholds can be determined based on the lidar device's structure, such as by determining the maximum and minimum field of view achievable by the lidar device when the rotating mirror is moved. This allows for the reasonable setting of the first and second thresholds, which can be the same or different.

[0038] It should be noted that changing the position of the rotating mirror can adjust the field of view in the X direction, and changing the position of the galvanometer can adjust the field of view in the Y direction. However, in this embodiment, only the position of the rotating mirror is changed, that is, only the field of view in the X direction is adjusted. In other embodiments, if it is necessary to change the field of view in the Y direction, slide rails can be set under the two rotating axes to achieve the change of the galvanometer position.

[0039] Furthermore, in different scenarios, the control system controls the swing angles of the first and second galvanometers and the rotation angle of the rotating mirror to achieve point cloud scanning in the X and Y directions. Specifically, in addition to moving the rotating mirror position via a slide rail to change the field of view of the lidar device in the X direction, the rotating mirror is also in a 360° rotating state during the operation of the lidar device, and the galvanometer is also in a continuously swinging state. The rotation of the rotating mirror enables the scanning of the signal light in the X direction, and the swing of the galvanometer enables the scanning of the signal light in the Y direction.

[0040] Specifically, such as Figure 2 As shown, the galvanometer, driven by the rotating shaft, can rotate uniformly along the shaft by several angles. The galvanometer rotates N angles, acting as a reflector. When a beam of light hits the galvanometer at its first rotation angle, the reflected light hits the mirror. The mirror rotates 360°, with each face occupying 90°, which can be further divided into N1 angles. When light hits the mirror at the first angle, the mirror reflects the light into space, forming the first point in the point cloud. The mirror rotates to the second angle, reflecting the light into space again, forming the second point, and so on until it completes a 90° rotation. This yields the first row of point clouds, represented by the N1 points in the X-direction on the point cloud map. The galvanometer then rotates to the next angle, reflecting light back onto the mirror. After a 90° rotation, the second row of point clouds is obtained. This process continues until the galvanometer has rotated N angles, resulting in N rows in the Y-direction on the point cloud map. The system repeatedly generates N rows during operation. N1 column point cloud.

[0041] In an optional implementation, when the application scenario is that the field of view of the lidar device is less than the field of view of the second threshold, the control system is further configured to control the swing angles of the first galvanometer and the second galvanometer to be different, so that the scanning points of the first wavelength signal light and the second wavelength signal light appear alternately in the Y direction.

[0042] Specifically, when the rotating mirror moves under the drive of the slide rail to adjust the field of view, when the horizontal field of view is adjusted to be small, if the swing angles of the left and right galvanometers are the same, the point clouds formed by the light emitted by each galvanometer after passing through the rotating mirror will be in a row, with the number of points in each row multiplied by 2. At this time, the swing angle ranges of the two galvanometers can be different. For example, the swing angles of the first galvanometer are 6.2°, 6.4°, 6.6°, etc., and the swing angles of the second galvanometer are 6.3°, 6.5°, 6.7°, etc. In this way, the light beams emitted by the two galvanometers to the rotating mirror will appear alternately in the Y direction, thereby obtaining denser point cloud data than a single wavelength scan.

[0043] In one alternative implementation, the first wavelength signal light and the second wavelength signal light have different reflectivities on the same target object, resulting in a coherent detection probability of the target object greater than a third threshold. Specifically, light signals of different wavelengths have different reflectivities on natural objects; one wavelength of light is largely reflected, while another wavelength may be rarely reflected. The reflection effects of the two wavelengths are complementary, which can improve the detection probability of the target object.

[0044] In one optional embodiment, the device further includes: a lidar chip and a scanning system, wherein the first wavelength coherent detection circuit and the second wavelength coherent detection circuit are disposed on the lidar chip, and the first galvanometer, the second galvanometer, and the rotating mirror are disposed in the scanning system; The lidar chip also includes a beam combining module, which is used to combine the first wavelength signal light and the second wavelength signal light to obtain a combined signal and input it to the scanning system. The beam combining module is also used to split the reflected first wavelength signal light and the second wavelength signal light and transmit them to the first wavelength coherent detection circuit and the second wavelength coherent detection circuit respectively. The scanning system further includes a beam splitting module, which is used to split the combined signal into beams, and then illuminate the first wavelength signal light after splitting into beams onto the first galvanometer and the second wavelength signal light after splitting into beams onto the second galvanometer. The beam splitting module is also used to combine the reflected first wavelength signal light and second wavelength signal light and transmit them to the beam combining module.

[0045] Specifically, to ensure that the two wavelength signal lights output by the lidar chip accurately illuminate the two galvanometers, in addition to the two wavelength coherent detection loops, a beam combining module is installed in the lidar chip. This beam combining module combines the two wavelength signal lights before transmitting them to the scanning system. Simultaneously, a beam splitting module is installed in the scanning system. This beam splitting module further splits the combined two wavelength signal lights and transmits them separately to the two galvanometers. Meanwhile, the two wavelength signal lights reflected back from the target object return along their original path; that is, the reflected two wavelength signal lights are reflected by the rotating mirror and galvanometers before re-entering the beam splitting module. The beam splitting module combines the reflected two wavelength signal lights before transmitting them to the lidar chip. The lidar chip's beam combining module receives the combined two wavelength signal lights, splits them, and transmits the split first and second wavelength signal lights to the first and second wavelength coherent detection loops, respectively.

[0046] It should be noted that by incorporating two wavelength coherent detection loops and a beam combining module into the lidar chip, and by setting the first galvanometer, the second galvanometer, the rotating mirror, and related control structures into the scanning system, the integration of the lidar device is improved.

[0047] In one optional embodiment, the beam combining module includes a wavelength mixer and an optical mode conversion waveguide; the wavelength mixer is used to combine the first wavelength signal light and the second wavelength signal light to obtain a combined signal light; the optical mode conversion waveguide is used to expand the combined signal light and input it into the scanning system; the optical mode conversion waveguide is also used to transmit the reflected first wavelength signal light and the second wavelength signal light to the wavelength mixer; the wavelength mixer is also used to split the reflected first wavelength signal light and the second wavelength signal light.

[0048] The beam splitting module includes a collimating lens and a wavelength splitter; the collimating lens is used to collimate the expanded and combined signal light and transmit it to the wavelength splitter; the wavelength splitter is used to split the collimated and combined signal light and illuminate the first galvanometer and the second galvanometer respectively; the wavelength splitter is also used to combine the reflected first wavelength signal light and the second wavelength signal light and transmit them to the collimating lens; the collimating lens is also used to transmit the reflected first wavelength signal light and the second wavelength signal light to the optical mode conversion waveguide.

[0049] Specifically, in the beam combining module, a wavelength mixer acts as a beam combiner, combining the two wavelength signal beams output from two coherent detection loops and sending them to the optical mode conversion waveguide. In the lidar chip, the waveguide used for light transmission, such as a silicon waveguide, has a relatively small beam size, approximately 0.22µm × 0.5µm. Therefore, an optical mode conversion waveguide with beam-expanding function is incorporated into the lidar chip to expand the beam to a size of 3µm × 3µm before transmitting it to the scanning system. This allows for better coupling with subsequent structures and improves coupling efficiency. The beam transmitted to the scanning system via the optical mode conversion waveguide first passes through a collimating lens in the beam splitting module to be collimated before being transmitted to a wavelength splitter. This wavelength splitter then splits the collimated beam and illuminates the first and second galvanometer mirrors respectively.

[0050] In addition, the wavelength splitter is also used to combine two wavelength signal beams reflected by the target object, and then enter the optical mode conversion waveguide of the lidar chip after passing through the collimating lens. The beams are then transmitted to the wavelength mixer, which splits the combined wavelength signal beams. The split wavelength signal beams are then coherently detected with the corresponding reference beams.

[0051] In one optional embodiment, the first wavelength coherent detection circuit includes a first optical waveguide coupler, a second optical waveguide coupler, a third optical waveguide coupler, a first balanced detector, and a first incident waveguide. The first input waveguide is used to receive a first wavelength optical signal and transmit the first wavelength optical signal to the second optical waveguide coupler. The second optical waveguide coupler is used to split the first wavelength optical signal into a first wavelength signal light and a first wavelength reference light. The first wavelength reference light is transmitted to the third optical waveguide coupler, and the first wavelength signal light is transmitted to the first optical waveguide coupler. The first optical waveguide coupler is used to output the first wavelength signal light. The first optical waveguide coupler is also used to receive the reflected first wavelength signal light and transmit the reflected first wavelength signal light to the third optical waveguide coupler. The third optical waveguide coupler is used to combine the first wavelength signal light and the first wavelength reference light and transmit them to the first balanced detector for coherent detection.

[0052] In one optional embodiment, the second wavelength coherent detection circuit includes a fourth optical waveguide coupler, a fifth optical waveguide coupler, a sixth optical waveguide coupler, a second balanced detector, and a second input waveguide. The second input waveguide is used to receive a second wavelength optical signal and transmit the second wavelength optical signal to the fifth optical waveguide coupler. The fifth optical waveguide coupler is used to split the second wavelength optical signal into a second wavelength signal light and a second wavelength reference light. The second wavelength reference light is transmitted to the sixth optical waveguide coupler, and the second wavelength signal light is transmitted to the fourth optical waveguide coupler. The fourth optical waveguide coupler is used to output the second wavelength signal light. The fourth optical waveguide coupler is also used to receive the reflected second wavelength signal light and transmit the reflected second wavelength signal light to the sixth optical waveguide coupler. The sixth optical waveguide coupler is used to combine the second wavelength signal light and the second wavelength reference light and transmit them to the second balanced detector for coherent detection.

[0053] As one or more specific application embodiments of the present invention, such as Figure 3 and Figure 4 As shown, the lidar device includes a lidar chip and a scanning system. The lidar chip includes a mode-spot conversion waveguide 1, a wavelength mixer 2, a first beam splitter coupler 3, a second beam splitter coupler 4, a third beam splitter coupler 5, a first balanced detector 6, a first input waveguide 7, a second input waveguide 8, a second balanced detector 9, a sixth beam splitter coupler 10, a fifth beam splitter coupler 11, and a fourth beam splitter coupler 12. The scanning system includes a multi-faceted rotating mirror 13 (which can be tetrahedral, pentahedral, etc.), a first galvanometer mirror 14 for scanning the beam in the Y direction, a wavelength splitter 15, a second galvanometer mirror 16 for scanning the beam in the Y direction, a reflector 17, a collimating mirror 18, and a sliding rail 19.

[0054] The first wavelength optical signal is input from the first input waveguide 7. The light is split into two paths by the second optical waveguide coupler 4. One path serves as the reference light (also known as the local light) and enters the third optical waveguide coupler 5. The other path serves as the signal light and enters the first optical waveguide coupler 3, before being transmitted to the wavelength mixer 2. The second wavelength optical signal is input from the second input waveguide 8. The light is split into two paths by the fifth optical waveguide coupler 11. One path serves as the reference light and enters the sixth optical waveguide coupler 10, while the other path serves as the signal light and enters the fourth optical waveguide coupler 12. The light is then transmitted to the wavelength mixer 2, and the two wavelength signal lights are finally output from the optical mode conversion waveguide 1.

[0055] Then, the signal light is transmitted to the same collimating mirror 18, and the two wavelength signal lights are separated by the wavelength splitter 15. The first wavelength signal light is irradiated by the first galvanometer 14 onto one side of the rotating mirror 13, and the second wavelength signal light is irradiated by the reflector 17 to the second galvanometer 16, and finally onto the other side of the rotating mirror 13.

[0056] by Figure 4 Using the position of rotating mirror 13 as a reference, the first wavelength signal light is horizontally projected onto the surface of rotating mirror 13 via the first galvanometer 14, and the second wavelength signal light is horizontally projected onto the other surface of rotating mirror 13 via the second galvanometer 16. To obtain a larger field of view (FOV), the system automatically moves rotating mirror 13 forward in slide rail 19, adjusting the relative positions of rotating mirror 13 with the first galvanometer 14 and the second galvanometer 16 as follows: Figure 5 As shown, the scanning range of the first wavelength signal light is indicated by the thick dashed line, and the scanning range of the second wavelength signal light is indicated by the light dashed line. The overlapping area of ​​the scanning ranges of the two beams is small, and the overall scanning range is larger than that of the single-surface scanning of the rotating mirror 13, resulting in a larger FOV.

[0057] To capture more detail of the target scene, the system automatically moves the rotating mirror 13 in the slide rail 19 backward, adjusting the relative positions of the rotating mirror 13 with the first galvanometer 14 and the second galvanometer 16 as follows: Figure 6 As shown, the scanning range of the first wavelength signal light is indicated by the thick dashed line, and the scanning range of the second wavelength signal light is indicated by the light dashed line. The scanning ranges of the two beams highly overlap. Adjusting the swing angle of the second galvanometer 16 to offset it from the first galvanometer 14, the scanning effect is as follows. Figure 7 The point cloud stitching diagram includes scanning points of the first wavelength signal light and scanning points of the second wavelength signal light. The two wavelength signal scanning points appear alternately in the Y direction to obtain denser point cloud data than a single wavelength scan.

[0058] Furthermore, light signals of different wavelengths have different reflectivities when they shine on natural objects. One wavelength of light is reflected in large quantities, while another wavelength of light may be reflected very little. The reflection effects of the two are complementary, which can improve the probability of detecting the target object.

[0059] In addition, after the two beams of light hit the target, the reflected light is coupled to the optical mode conversion waveguide 1 of the lidar chip through the scanning system. The two wavelength return light signals are split into two paths by the wavelength mixer 2. The first wavelength signal light is mixed with the first wavelength reference light by the first optical waveguide coupler 3 and then enters the first balanced detector 6 for photoelectric conversion. The second wavelength signal light is mixed with the second wavelength reference light by the fourth optical waveguide coupler 12 and then enters the second balanced detector 9 for photoelectric conversion. Finally, the radar system processes the two wavelength point cloud data.

[0060] In this invention, the lidar chip of the lidar device features two coherent detection photon circuits of different wavelengths. These circuits are output through the same waveguide and transmitted to the scanning system via the same collimating lens. The light is then split into two parts by a wavelength splitter, passed through a galvanometer, and projected onto the two surfaces of a rotating mirror. Simultaneously, the relative positions of the rotating mirror and the galvanometer are adjusted in real time according to the target scene, enabling large field-of-view scanning or point cloud stitching focusing on key areas. This improves local detection density and matches the perception needs of different environments in various scenarios. This not only enhances the utilization rate of the rotating mirror but also solves the problem of a fixed field of view in ordinary FMCW lidar.

[0061] While exemplary embodiments and their advantages have been described in detail, those skilled in the art can make various changes, substitutions, and modifications to these embodiments without departing from the spirit of the invention and the scope of protection defined by the appended claims. Such modifications and variations all fall within the scope defined by the appended claims. For other examples, those skilled in the art should readily understand that the order of process steps can be changed while remaining within the scope of the invention.

[0062] Furthermore, the scope of this invention is not limited to the processes, mechanisms, manufacturing methods, material compositions, means, methods, and steps of the specific embodiments described in the specification. From the disclosure of this invention, those skilled in the art will readily understand that any existing or future processes, mechanisms, manufacturing methods, material compositions, means, methods, or steps that perform substantially the same function or obtain substantially the same results as the corresponding embodiments described in this invention can be applied according to this invention. Therefore, the appended claims are intended to include these processes, mechanisms, manufacturing methods, material compositions, means, methods, or steps within their scope of protection.

Claims

1. A lidar device, characterized in that, The device includes: a first wavelength coherent detection circuit, a second wavelength coherent detection circuit, a first galvanometer, a second galvanometer, and a rotating mirror; The first wavelength coherent detection circuit is used to split the first wavelength optical signal into a first wavelength reference light and a first wavelength signal light, and input the first wavelength signal light to the first galvanometer. The second wavelength coherent detection circuit is used to split the second wavelength optical signal into a second wavelength reference light and a second wavelength signal light, and input the second wavelength signal light to the second galvanometer. The first galvanometer is used to illuminate the first wavelength signal light onto the first surface of the rotating mirror; The second galvanometer is used to illuminate the second wavelength signal light onto the second surface of the rotating mirror; The rotating mirror illuminates the first wavelength signal light and the second wavelength signal light onto the same target object, and receives the first wavelength signal light and the second wavelength signal light reflected by the target object. After the reflected first wavelength signal light and the second wavelength signal light pass through the first galvanometer and the second galvanometer respectively, the reflected first wavelength signal light enters the first wavelength coherent detection circuit and the first wavelength reference light for coherent detection, and the reflected second wavelength signal light enters the second wavelength coherent detection circuit and the second wavelength reference light for coherent detection. When the lidar device is applied to different scenarios, the positions and angles of the first galvanometer, the second galvanometer, and the rotating mirror are different, so that the overlap of the scanning ranges of the first wavelength signal light and the second wavelength signal light is different, and the field of view of the lidar device is different.

2. The lidar device according to claim 1, characterized in that, The device further includes: a first rotating shaft, a second rotating shaft, a slide rail, and a control system; The first galvanometer is mounted on the first rotating shaft, the second galvanometer is mounted on the second rotating shaft, and the rotating mirror is mounted on the slide rail; The control system is used to control the swing angle of the first galvanometer and the second galvanometer via the first rotating shaft and the second rotating shaft, change the position of the galvanometer via the slide rail, and change the rotation angle of the galvanometer.

3. The lidar device according to claim 2, characterized in that: When the application scenario is that the field of view of the lidar device is greater than the first threshold field of view, the control system controls the rotating mirror to move closer to the first galvanometer and the second galvanometer via the slide rail; When the application scenario is that the field of view of the lidar device is less than the field of view of the second threshold, the control system controls the rotating mirror to move away from the first galvanometer and the second galvanometer via the slide rail; In different scenarios, the control system controls the swing angle of the first galvanometer and the second galvanometer, as well as the rotation angle of the rotating mirror, to achieve point cloud scanning in the X and Y directions.

4. The lidar device according to claim 2, characterized in that, When the application scenario is that the field of view of the lidar device is less than the field of view of the second threshold, the control system is also used to control the swing angle of the first galvanometer and the second galvanometer to be different, so that the scanning points of the first wavelength signal light and the second wavelength signal light appear alternately in the Y direction.

5. The lidar device according to claim 1, characterized in that, The first wavelength signal light and the second wavelength signal light have different reflectivities on the same target object, and the coherent detection probability of the target object is greater than the third threshold.

6. The lidar device according to claim 1, characterized in that, The device further includes: a lidar chip and a scanning system, wherein the first wavelength coherent detection circuit and the second wavelength coherent detection circuit are disposed on the lidar chip, and the first galvanometer, the second galvanometer, and the rotating mirror are disposed on the scanning system; The lidar chip also includes a beam combining module, which is used to combine the first wavelength signal light and the second wavelength signal light to obtain a combined signal and input it to the scanning system. The beam combining module is also used to split the reflected first wavelength signal light and the second wavelength signal light and transmit them to the first wavelength coherent detection circuit and the second wavelength coherent detection circuit respectively. The scanning system further includes a beam splitting module, which is used to split the combined signal into beams, and then illuminate the first wavelength signal light after splitting into beams onto the first galvanometer and the second wavelength signal light after splitting into beams onto the second galvanometer. The beam splitting module is also used to combine the reflected first wavelength signal light and second wavelength signal light and transmit them to the beam combining module.

7. The lidar device according to claim 6, characterized in that, The beam combining module includes a wavelength mixer and an optical mode conversion waveguide; The wavelength mixer is used to combine the first wavelength signal light and the second wavelength signal light to obtain a combined signal light; The optical mode conversion waveguide is used to amplify the combined signal light and input it into the scanning system; The optical mode conversion waveguide is also used to transmit the reflected first wavelength signal light and second wavelength signal light to the wavelength mixer; The wavelength mixer is also used to split the reflected first wavelength signal light and the second wavelength signal light into beams.

8. The lidar device according to claim 7, characterized in that, The beam splitting module includes: a collimating lens and a wavelength splitter; The collimating lens is used to collimate the expanded and combined signal light and transmit it to the wavelength splitter. The wavelength splitter is used to split the collimated beam-combined signal into beams that are then directed onto the first and second galvanometers respectively. The wavelength splitter is also used to combine the reflected first wavelength signal light and second wavelength signal light and transmit them to the collimating lens. The collimating lens is also used to transmit the reflected first wavelength signal light and second wavelength signal light to the optical mode conversion waveguide.

9. The lidar device according to claim 1, characterized in that, The first wavelength coherent detection circuit includes a first optical waveguide coupler, a second optical waveguide coupler, a third optical waveguide coupler, a first balanced detector, and a first input waveguide; The first input waveguide is used to receive a first wavelength optical signal and transmit the first wavelength optical signal to the second optical waveguide coupler. The second optical waveguide coupler is used to split the first wavelength optical signal into a first wavelength signal light and a first wavelength reference light. The first wavelength reference light is transmitted to the third optical waveguide coupler, and the first wavelength signal light is transmitted to the first optical waveguide coupler. The first optical waveguide coupler is used to output the first wavelength signal light. The first optical waveguide coupler is also used to receive the reflected first wavelength signal light and transmit the reflected first wavelength signal light to the third optical waveguide coupler. The third optical waveguide coupler is used to combine the first wavelength signal light and the first wavelength reference light and transmit them to the first balanced detector for coherent detection.

10. The lidar device according to claim 1, characterized in that, The second wavelength coherent detection circuit includes a fourth optical waveguide coupler, a fifth optical waveguide coupler, a sixth optical waveguide coupler, a second balanced detector, and a second input waveguide; The second input waveguide is used to receive a second wavelength optical signal and transmit the second wavelength optical signal to the fifth optical waveguide coupler. The fifth optical waveguide coupler is used to split the second wavelength optical signal into a second wavelength signal light and a second wavelength reference light. The second wavelength reference light is transmitted to the sixth optical waveguide coupler, and the second wavelength signal light is transmitted to the fourth optical waveguide coupler. The fourth optical waveguide coupler is used to output the second wavelength signal light. The fourth optical waveguide coupler is also used to receive the reflected second wavelength signal light and transmit the reflected second wavelength signal light to the sixth optical waveguide coupler. The sixth optical waveguide coupler is used to combine the second wavelength signal light and the second wavelength reference light and transmit them to the second balanced detector for coherent detection.

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