Lidar

Abstract

The application provides a laser radar, which comprises a plurality of optical channels and a scanning device; the plurality of outgoing light provided by the plurality of optical channels is converged on the scanning device; the scanning device is used for receiving the plurality of outgoing light to scan and emit; and is also used for receiving a plurality of echo light beams to make the plurality of echo light beams enter the plurality of optical channels respectively to detect; the plurality of optical channels comprises: a transmitting device, which is used for providing a plurality of transmitting light beams; a plurality of reflecting units, which are used for reflecting the plurality of transmitting light beams respectively to form the outgoing light converged on the scanning device; and are also used for receiving the plurality of echo light beams scanned by the scanning device to reflect the plurality of echo light beams; a receiving device, which is used for detecting the plurality of echo light beams; and a light beam changing device, which is located on the light paths between the transmitting device and the reflecting units and between the reflecting units and the receiving device, and is used for increasing the distance between the plurality of transmitting light beams and decreasing the distance between the plurality of echo light beams. The application improves the compactness of the light path and reduces the difficulty of assembling and adjusting the transmitting device and the receiving device.

Description

Technical Field

[0001] This invention relates to the field of lidar, and more particularly to a scanning lidar. Background Technology

[0002] LiDAR plays an important role in autonomous driving, including curb detection, obstacle recognition, and real-time localization and mapping (SLAM).

[0003] Specifically, a LIDAR system includes a laser emitting system and a light receiving system. The laser emitting system includes a light emitting unit that generates an emitted light pulse. This emitted light pulse is incident on a target object and reflected to produce an echo beam, which is ultimately received by the light receiving system. The receiving system accurately measures the propagation time of the incident light pulse from emission to its reflection. Because the light pulse propagates at the speed of light, and the speed of light is known, the propagation time can be converted into a distance measurement.

[0004] LiDAR can accurately measure the position (distance and angle), motion state (velocity, vibration, and attitude), and shape of targets, enabling it to detect, identify, distinguish, and track targets. Due to its advantages such as high measurement speed, high accuracy, and long range, LiDAR has been widely used in autonomous vehicles.

[0005] However, publicly available technologies such as lidar suffer from the problem of insufficiently compact optical paths. Summary of the Invention

[0006] The problem solved by this invention is to provide a lidar that improves the compactness of the optical path.

[0007] To address the aforementioned technical problems, this invention provides a lidar, comprising multiple optical channels and a scanning device. The multiple optical channels provide multiple emitted beams, which are converged by the scanning device. The scanning device receives the multiple emitted beams and scans them; it also receives echo beams formed after the emitted beams are reflected by a target object, allowing the echo beams to enter the multiple optical channels for detection. Each multiple optical channel includes: a transmitting device for providing multiple emitted beams; multiple reflecting units for reflecting the emitted beams to form emitted beams converged by the scanning device; and receiving echo beams scanned by the scanning device and reflecting them; a receiving device for detecting the multiple echo beams; and a beam-changing device located on the optical path between the transmitting device and the reflecting units, and between the reflecting units and the receiving device, for increasing the distance between the multiple emitted beams and decreasing the distance between the multiple echo beams.

[0008] Optionally, the beam-changing device is further configured to expand the emitted beam and compress the echo beam.

[0009] Optionally, in the multiple optical channels, the plane from the beam changing device to the plane where the reflecting unit is located is a first plane; in the first plane, the optical path direction of the emitted beam from the beam changing device to the reflecting unit is a first direction, and the direction perpendicular to the first direction is a second direction; the emitting device provides the emitted beam in a direction perpendicular to the first plane; the receiving device detects the echo beam returning in a direction perpendicular to the first plane.

[0010] Optionally, the beam changing device includes: a first reflector group located on the first plane and corresponding to the position of the transmitting device, for receiving the emitted beam provided by the transmitting device and deflecting the emitted beam in a second direction; and a second reflector group including a plurality of separate first reflectors, the position of each first reflector corresponding to the position of the reflecting unit, for receiving the emitted beam reflected by the first reflector group and deflecting the emitted beam in a first direction.

[0011] Optionally, the lidar further includes: a plurality of first convex lenses, respectively located between the reflecting unit and the beam changing device; the beam changing device further includes: a plurality of second convex lenses, respectively located between the first reflecting mirror group and the second reflecting mirror group, wherein the diameter of the second convex lens is smaller than the diameter of the first convex lens.

[0012] Optionally, the first reflector is used to deflect the emitted beam in a first direction and then project it onto the first convex lens.

[0013] Optionally, the beam changing device includes: a third reflector group located on a second plane parallel to the first plane and corresponding to the position of the transmitting device, for receiving the emitted beam and deflecting the emitted beam in a second direction on the second plane; a fourth reflector group including a plurality of second reflectors located on the second plane and separated from each other, the position of each second reflector on the first plane corresponding to the position of each of the reflecting units, for receiving the emitted beam reflected by the third reflector group and deflecting the emitted beam in a direction perpendicular to the first plane; and a fifth reflector group including a plurality of third reflectors located on the first plane and corresponding to the positions of the second reflectors, the plurality of third reflectors being staggered in the first direction for deflecting the emitted beam in a first direction within the first plane.

[0014] Optionally, the multi-path optical channel further includes: a plurality of third convex lenses, respectively located between the reflecting unit and the beam changing device; a plurality of fourth convex lenses, respectively located between the second reflecting mirror and the third reflecting mirror; the diameter of the fourth convex lens is smaller than the diameter of the third convex lens.

[0015] Optionally, the third reflector is used to deflect the emitted beam in the first direction and then project it onto the third convex lens.

[0016] Optionally, the transmitting device includes: a transmitting unit array for providing the multiple transmitted beams; the receiving device includes: a receiving unit array for detecting the multiple echo beams.

[0017] Optionally, the lidar further includes: a beam splitter for transmitting the emitted beam provided by the transmitting unit array and for reflecting the echo beam to the receiving unit array; or, for reflecting the emitted beam provided by the transmitting unit array and for transmitting the echo beam to the receiving unit array.

[0018] Optionally, the beam splitter includes: a polarization beam splitter for transmitting light of one polarization state and reflecting light of another polarization state; and a waveplate for adjusting the polarization state of the emitted beam and the echo beam.

[0019] Optionally, the polarization beam splitter is a polarization beam splitter prism or a polarization beam splitter sheet.

[0020] Optionally, the lidar further includes a lens array located between the beam splitter and the receiving unit array. The lens array includes multiple lenses with different eccentricities to deflect some or all of the echo beams to reduce the distance between the multiple echo beams.

[0021] Optionally, the echo beam received by the lens array includes: a first echo beam close to the receiving unit array and a second echo beam away from the receiving unit array relative to the first echo beam, wherein the lens eccentricity corresponding to the second echo beam is greater than the lens eccentricity corresponding to the first echo beam.

[0022] Optionally, the lidar further includes: a prism array located between the beam splitter and the receiving unit array, the prism array including multiple prisms with different wedge angles, used to deflect the echo beam to increase the distance between the multiple echo beams; and a converging lens located between the prism array and the receiving unit array, used to converge the deflected echo beam.

[0023] Optionally, the echo beams received by the prism array include: a first echo beam close to the receiving unit array and a second echo beam away from the receiving unit array relative to the first echo beam, wherein the prism wedge angle corresponding to the second echo beam is greater than the prism wedge angle corresponding to the first echo beam.

[0024] Optionally, the multi-channel optical path further includes a correction unit for ensuring that the multiple light spots formed by the outgoing light from the multi-channel optical path are parallel to each other in a specific direction.

[0025] Optionally, the correction unit is a Dowell prism located between the transmitting device and the beam changing device.

[0026] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0027] The lidar of this invention uses a beam-changing device to increase the distance between multiple transmitted beams and decrease the distance between multiple echo beams, thereby making the transmitted beams have a narrow beam at a position close to the transmitting and receiving devices relative to a position far from the transmitting and receiving devices. This improves the optical path compactness of the lidar and reduces the product size.

[0028] Furthermore, embodiments of the present invention provide a beam-changing device in the optical path, enabling the lidar to have a wide beam at a position far from the transmitting and receiving devices. By switching between wide and narrow beams, the purpose of achieving independence and no spatial interference between multiple optical channels can be realized. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the optical path of a lidar in publicly available technology;

[0030] Figure 2 This is a schematic diagram of the optical path of the lidar according to the first embodiment of the present invention;

[0031] Figure 3 yes Figure 2 The diagram shows the structure of a lidar.

[0032] Figure 4 yes Figure 2 A schematic diagram of the optical path of a laser emitting and receiving device.

[0033] Figure 5 yes Figure 4 A schematic diagram of the device shown;

[0034] Figure 6 This is a schematic diagram of the optical path of the lidar according to the second embodiment of the present invention;

[0035] Figure 7 This is a schematic diagram of the optical path of the lidar according to the third embodiment of the present invention;

[0036] Figure 8 This is a schematic diagram of the optical path of the lidar according to the fourth embodiment of the present invention. Detailed Implementation

[0037] As described in the background section, the disclosed lidar technology suffers from the problem that the optical path with multiple optical channels is not compact enough. Figure 1The diagram shows the optical path of a lidar in the disclosed technology, and analyzes the cause of the aforementioned problem. It should be noted that, for simplicity and clarity, the diagram uses a four-channel optical path as an example.

[0038] like Figure 1 The lidar shown includes multiple optical channels 1, 2, 3, and 4, and a scanning device 14. Each optical channel includes: a light source 10 for providing an emitted beam, a beam splitter 11 for transmitting the emitted beam, a lens 12 for converging the emitted beam, and a reflector 13 for reflecting the emitted beam to the scanning device 14. The scanning device 14 scans the multiple emitted beams to form an emitted beam E for detecting the target object. The scanning device 14 also receives the echo beam formed by the reflection of the emitted beam E from the target object and scans the echo beam, allowing it to enter each of the multiple optical channels for detection. Specifically, in each optical channel, the echo beam is reflected by the beam splitter 11 and projected onto the detector 15 to achieve echo beam detection.

[0039] like Figure 1 In this design, due to the large distance between the four optical channels, separate light sources 10 and detectors 15 are required, typically necessitating multiple transmitters and receivers. Therefore, the lidar suffers from poor optical path compactness. Furthermore, installation requires mounting and adjusting the optical paths of each optical channel's transmitter and multiple receivers, resulting in low production efficiency.

[0040] To improve the compactness of the optical path, this invention provides a lidar including multiple optical channels and a scanning device. The multiple optical channels include: a transmitting device for providing multiple emitted beams; multiple reflecting units for reflecting the emitted beams to form the outgoing light converged at the scanning device; and a receiving device for receiving and reflecting the echo beams scanned by the scanning device; a receiving device for detecting the multiple echo beams; and a beam-changing device located on the optical path between the transmitting and reflecting units and between the reflecting units and the receiving device, for increasing the distance between the multiple emitted beams and decreasing the distance between the multiple echo beams.

[0041] The lidar of this invention uses a beam-changing device to increase the distance between multiple transmitted beams and decrease the distance between multiple echo beams, thereby making the transmitted beams narrower relative to the positions far from the transmitting and receiving devices, and closer to the transmitting and receiving devices, thus improving the optical path compactness of the lidar and reducing the product size.

[0042] Furthermore, by setting a beam-changing device in the optical path, the present invention enables the lidar to have a wide beam at a position far from the transmitting and receiving devices. By switching between the wide and narrow beams, the invention facilitates the goal of achieving independence and no spatial interference between multiple optical channels.

[0043] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0044] refer to Figure 2 and Figure 3 The diagrams show the optical path and structure of the lidar according to the first embodiment of the present invention. It should be noted that the lidar in this embodiment is a scanning lidar, comprising: multiple optical channels a, b, c, and d, and a scanning device 104.

[0045] Multiple optical channels a, b, c, and d are used to provide multiple beams for detection. This example uses four optical channels a, b, c, and d. In other embodiments, the number of optical channels can be two, three, five, etc.

[0046] The scanning device 104 is used to receive the multi-channel emitted light for scanning; it is also used to receive the echo beam formed after the emitted light is reflected by the target object, so that the echo beam enters the multi-channel optical channels a, b, c, and d for detection.

[0047] Specifically, the scanning device 104 can be a scanning galvanometer, which scans and reflects the emitted beams from multiple optical channels to form outgoing light for detecting the target object. The outgoing light is reflected by the target object to form an echo beam, which is then reflected by the scanning galvanometer and enters each optical channel.

[0048] The multi-channel optical system includes: a transmitting device 100, multiple reflecting units 103, a receiving device 105, and a beam changing device 110.

[0049] The transmitting device 100 is used to provide a transmitted light beam. In this embodiment, the transmitted light beams provided by the multi-channel optical transmitting device are parallel to each other.

[0050] Specifically, the emitting device 100 employs an edge-emitting laser (EEL). EELs are characterized by miniaturization, stable coherent light, and narrow emission wavelength, making them widely used in lidar. In other embodiments, the emitting device 100 may also be a vertical-cavity surface-emitting laser (VCSEL).

[0051] In this embodiment, the EEL is a laser light source, and the emitting device 100 may include multiple EELs. For example... Figure 3 In the present embodiment, the multiple EELs in the transmitting device 100 are arranged in a one-dimensional manner. In other embodiments, the multiple EELs may also be arranged in a two-dimensional manner.

[0052] Multiple reflection units 103 are used to change the propagation direction of the emitted light beam to form the emitted light that is converged in the scanning device 104; they are also used to receive the echo beam scanned by the scanning device 104 and reflect the echo beam.

[0053] In this embodiment, the reflecting unit 103 is an independent reflecting mirror located in each optical channel. Since the multiple optical channels are distributed at different positions in the scanning device 104, and the emitting device 100 provides mutually parallel emitting beam lines, in order to converge the reflected light from each optical channel to the scanning device 104, the reflecting mirrors of each optical channel have different spatial arrangement positions, that is, the reflecting mirrors of each optical channel have different spatial angle normal directions.

[0054] The receiving device 105 is used to detect multiple echo beams in order to enable the lidar to detect targets.

[0055] Specifically, the receiving device 105 is typically a photodetector that converts optical signals into electrical signals. For example, the photodetector is an avalanche photodiode (APD), a silicon photomultiplier tube (SiPM), or a single-photon avalanche diode (SPAD) array. In this embodiment, the receiving device 105 is a linear APD array composed of multiple APDs arranged in a straight line.

[0056] A beam alteration device 110, located between the transmitting device 100 and the plurality of reflecting units 103, is used to increase the distance between the multiple transmitted beams. The beam alteration device 110 is also located in the optical path between the reflecting units 103 and the receiving device 105, and is used to decrease the distance between the multiple echo beams.

[0057] The transmitting device 100 and the receiving device 105 are located on the same side of the beam changing device 110. Specifically, the transmitting device 100 and the receiving device 105 are both located on the side of the beam changing device 110 away from the reflecting unit 103 in the optical path.

[0058] The lidar of this embodiment of the invention, by incorporating a beam-changing device 110, increases the distance between multiple emitted beams and decreases the distance between multiple echo beams. This results in the emitted beams having a narrow beam position near the emitter 100 and receiver 105, relative to the side furthest from the emitter 100 and receiver 105. This improves the optical path compactness of the lidar and reduces the product size. It should be noted that the distance between beams here refers to the distance between optical axes.

[0059] Furthermore, by setting a beam changing device 110 in the optical path, the lidar has a wide beam at a position far away from the transmitting device 100 and the receiving device 105. By switching between the wide beam and the narrow beam, the purpose of achieving independence and no spatial interference between multiple optical channels can be achieved.

[0060] The lidar in this embodiment of the invention further includes a lens 102, used to focus the emitted beam onto the reflective unit 103 to improve the light utilization rate of the emitted beam.

[0061] like Figure 2 As shown, the lens 102 consists of multiple first convex lenses, which are located between each reflection unit 103 and the beam changing device 110. The first convex lenses are used to expand the emitted beam and to compress the echo beam.

[0062] Please continue to refer to this. Figure 2 and Figure 3 In this embodiment, in the multiple optical channels, the plane from the beam changing device 110 to the reflection unit 103 is the first plane (XY plane); in the first plane XY, the optical path direction of the emitted beam from the beam changing device 110 to the reflection unit 103 is the first direction (Y direction), and the direction perpendicular to the first direction Y is the second direction (X direction). The emitting device 100 provides the emitted beam along the direction perpendicular to the first plane XY (Z direction); the receiving device 105 detects the echo beam returning along the direction Z perpendicular to the first plane XY.

[0063] In this embodiment of the lidar, the transmitting device 100 and the receiving device 105 are positioned along the optical path in the Z direction, perpendicular to the first plane XY. This fully utilizes the vertical space in the Z direction, improving the compactness of the lidar structure and reducing its size. Furthermore, since the transmitting device 100 and the receiving device 105 are not located within the first plane XY, more space is freed up for optical components within the first plane XY, increasing the possibility and flexibility of arranging optical components within the first plane XY.

[0064] The beam changing device 110 includes: a first reflector group 111, located in the first plane XY and corresponding to the position of the transmitting device 100, for receiving the emitted beam provided by the transmitting device 100 and deflecting the emitted beam in the second direction X.

[0065] Specifically, in this embodiment, the transmitting device 100 provides four parallel emitted beams along the Z direction perpendicular to the first plane XY. The meaning of the first reflector group 111 corresponding to the position of the transmitting device 100 is that the first reflector group 111 is located at the position of the transmitting device 100 on the first plane XY that can reflect the emitted beams.

[0066] Compared to Figure 1 The four separately arranged transmitting devices 1-4 shown have four emitted beams that are relatively close to each other. For example, the transmitting device 100 may be an embodiment of a linear array laser composed of multiple lasers on the same laser plate, with the distance between the lasers on the order of millimeters. Therefore, the distance between the emitted beams is also on the order of millimeters, resulting in a close proximity between the emitted beams. In contrast, the distance between the separately arranged multiple transmitting devices is typically on the order of centimeters, indicating a greater distance between them. Correspondingly, the first reflector group 111 includes four mirrors arranged side by side and adjacent to each other, each reflecting the emitted beam from each optical channel. That is, each mirror receives the four emitted beams from the transmitting device 100 and reflects the emitted beams in the second direction X.

[0067] It should be noted that in the four parallel and adjacent reflectors in this embodiment of the invention, adjacent reflectors face opposite directions, used to reflect adjacent emitted beams in different directions. In other embodiments, adjacent optical paths can share a single reflector to reflect adjacent emitted beams in the same direction. For example, two reflectors with opposite reflection directions can be used, one reflector reflecting two adjacent emitted beams so that they propagate in the forward X direction, and the other reflector reflecting two adjacent emitted beams so that they propagate in the reverse X direction. By sharing a single reflector between two adjacent optical paths, the number of reflectors can be reduced.

[0068] It should also be noted that, in order to make the optical path lengths of the four optical channels relatively close, in this embodiment of the invention, the emitting device is located at the center of the four optical channels. To ensure that the four emitted beams are reflected to their respective optical channel positions, the mirrors in the first mirror group 111 have different orientations. In other embodiments, if the light-emitting device is located on the same side of the four optical channels, the mirrors in the first mirror group can have the same orientation. Correspondingly, the first mirror group 111 can use only one mirror, meaning multiple optical channels share one mirror. The second mirror group 131 includes multiple separate first mirrors 113, the position of each first mirror 113 corresponding to the position of the reflecting unit 103, for receiving the emitted beam reflected by the first mirror group 111 and deflecting the emitted beam in the first direction Y.

[0069] Multiple separate first reflectors 113 correspond to the positions of the reflective unit 103, that is, the first reflectors 113 are located on the optical axis of each optical channel.

[0070] The first reflector group 111 receives emitted beams that are close to each other along the optical axis in the Z direction and causes the emitted beams to propagate in the X direction. Then, the propagation path of the emitted beams changes at the position of the first reflector 113, and they are redirected to the optical axis directions of each optical channel, resulting in a larger distance between the optical axis channels. In this embodiment of the invention, the beam changing device 110, through the cooperation of the first reflector group 111 and the second reflector group 131, achieves the purpose of increasing the distance between the optical axes of the multiple emitted beams.

[0071] Based on the reversibility of the optical path, when the echo beam returns to the receiving device 105 via the second reflector group 131 and the first reflector group 111 in sequence, the distance between the multiple echo beams can be reduced.

[0072] In this embodiment, a first convex lens 102 is also provided in each optical channel along the optical path of the emitted beam. The first reflector 113 is used to deflect the emitted beam in the first direction Y and then project it onto the first convex lens 102, and then onto each reflector unit 103.

[0073] Continue to refer to Figure 2 and Figure 3 The beam changing device 110 further includes a plurality of second convex lenses 112, respectively located between the first reflector group 111 and the second reflector group 131, wherein the diameter of the second convex lens 112 is smaller than the diameter of the first convex lens 102. That is, relative to the large-sized first convex lens 102 near the reflecting unit 103 in the optical path, the second convex lenses 112 in the beam changing device 110 are small lenses to accommodate the aperture of the beam in the beam changing device 110.

[0074] For any one of the optical channels, the emitted beam first passes through the small second convex lens 112 and then through the large first convex lens 102, changing the emitted beam from a narrow beam to a wide beam in the direction of the emitted light path, thus achieving the effect of beam expansion; while the echo beam first passes through the large first convex lens 102 and then through the small second convex lens 112, changing the echo beam from a wide beam to a narrow beam in the direction of the received light path, thus achieving the effect of beam compression. This enables the multiple optical channels to be independent of each other and free from spatial interference, further improving the compactness of the lidar transmitting and receiving devices.

[0075] Please continue to refer to this. Figure 2 and Figure 3 The mirrors in each optical channel have different spatial angles, such as Figure 2 As shown in figures a and d, the spatial incident angle (i.e., the angle between the optical axis of the emitted light and the normal of the reflecting mirror) is relatively large, while the spatial incident angles in figures b and c are relatively small. This results in different rotation angles of the emitted light spot formed after scanning by the scanning device 104. Specifically, the larger the spatial incident angle, the larger the rotation angle of the light spot. In addition, the rotation directions of the emitted light spot also differ in the optical channels distributed on opposite sides of the scanning device.

[0076] In the lidar of this embodiment of the invention, the multi-channel optical system further includes a correction unit 160, used to make the multiple light spots formed by the outgoing light of the multi-channel optical system parallel to each other in a specific direction. By making the multiple light spots formed by the outgoing light parallel to each other, that is, the outgoing light spots between the multiple optical channels have no relative rotation angle, the spatial arrangement of the outgoing light spots of the multi-channel system is improved, thereby increasing the coverage range of the outgoing light spots.

[0077] like Figure 3 As shown, the correction unit 160 is a Dowell prism located between the transmitting device 100 and the beam changing device 110.

[0078] It should be noted that in this embodiment of the invention, the emitted light spot is an elliptical light spot, and the specific direction is the slow axis direction of the elliptical light spot (i.e., the major axis direction of the ellipse). For example, the slow axis direction is a vertical direction, and the light spots of each channel are parallel to each other in the slow axis direction. In this way, multiple light spots are parallel in the extension direction of the maximum size of the light spot, which can further improve the detection coverage.

[0079] The Daowei prism utilizes the critical angle principle to achieve total internal reflection. Under the premise that the direction of the incident light remains unchanged, when the Daowei prism 106 rotates around its optical axis by an angle θ, the rotation angle of the outgoing light is 2θ (that is, the rotation angle of the outgoing light is twice the rotation angle of the prism itself).

[0080] Since multiple optical channels are distributed at different positions in the scanning device, the spatial incident angle of each optical path is different, and correspondingly, the rotation angle of the light spot that needs to be corrected is also different.

[0081] Reference Figure 3 The angle of rotation of the Daowei prism around its optical axis is set such that the light spots formed by the outgoing light corresponding to the multiple optical channels are parallel to each other.

[0082] Continue to refer to Figure 4 and Figure 5 , indicating Figure 2 and Figure 3 Enlarged view of the transmitting and receiving devices. Figure 4 This is the optical path diagram. Figure 5 This is a schematic diagram of the structure.

[0083] The transmitting device 100 includes a transmitting unit array for providing the multiple transmitted beams. The transmitting unit array can be formed on a transmitting board. Correspondingly, the receiving device 105 includes a receiving unit array for detecting the multiple echo beams. The transmitting array can be formed on a receiving board. This embodiment of the invention uses a transmitting unit array and a receiving unit array, improving the integration of the device. Furthermore, as... Figure 5 The transmitter and receiver are arranged in parallel, which improves the structural compactness of the lidar.

[0084] It should be noted that Figure 4 The following description uses a one-dimensional linear array emitting unit as an example. In other embodiments, the emitting unit array can also be a planar array emitting unit, including multiple columns (or rows) of linear array emitting units. For example, the emitting unit array includes two columns of linear array emitting units, where one column of linear array emitting units is deflected in the positive direction along the X direction after being reflected by the first set of mirrors, and the other column of linear array emitting units is deflected in the negative direction along the X direction after being reflected by the first set of mirrors. As another example, the emitting unit array includes three or more columns of linear array emitting units. It can utilize the vertical space in the Z direction to arrange multiple optical channels similar to the XY plane on multiple planes perpendicular to Z (e.g., X1Y1, X2Y2), respectively corresponding to propagating the emitted beams emitted by different columns of linear array emitting units of the planar array emitting unit.

[0085] Continue to refer to Figure 4 and Figure 5 The lidar further includes a beam splitter 101, used to reflect the emitted beam provided by the emitting unit array and to transmit the echo beam to the receiving unit array.

[0086] The lidar also includes a lens array 120 located in the optical path between the transmitting device 100 and the beam splitter 101, for collimating the emitted beam.

[0087] The beam splitter 101 includes: a polarization beam splitter 1012 for transmitting light of one polarization state and reflecting light of another polarization state; and a waveplate 1011 for adjusting the polarization state of the emitted beam and the echo beam.

[0088] Specifically, the polarization beam splitter 1012 can be a polarization beam splitter (PBS) or a polarization beam splitter. The waveplate 1011 can be a quarter-wave plate.

[0089] For example, the polarization beam splitter 1012 is a polarization beam splitter prism used to reflect S-polarized light and transmit P-polarized light. The light emitted by the transmitting unit 100 includes S-polarized light, whose polarization state remains unchanged after passing through the lens array 120. At the polarization beam splitter 1012, the S-polarized light is reflected and then its polarization state is adjusted by a quarter-wave plate, becoming the emitted beam E. When the emitted beam E is reflected by the target to form the echo beam B, it returns and its polarization state is adjusted again by a quarter-wave plate, becoming P-polarized light. The P-polarized light is transmitted through the polarization beam splitter 1012 and enters the receiving optical path, thereby achieving the purpose of beam splitting.

[0090] It should be noted that, in other embodiments, the beam splitter can also be configured to: transmit the emitted beam provided by the transmitting unit array, and reflect the echo beam to the receiving unit array. Furthermore, the beam splitter can also employ other principles to achieve beam splitting.

[0091] Continue to refer to Figure 4 After the echo beam B is transmitted through the polarization beam splitter 1012, it is projected onto the filter 130. The filter 130 is used to allow light of wavelengths that can be detected by the receiving device 105 to pass through, and to filter out light that cannot be detected, thereby reducing the noise interference of the receiving device 105.

[0092] In addition, the lidar also includes a lens group 140, located between the beam splitter 101 and the receiving unit array, for converging the echo beam B onto the receiving device 105, thereby increasing the light intensity of the echo beam B.

[0093] like Figure 5 As shown, the transmitting device 100 and the receiving device 105 of the present invention can be integrated together, resulting in a smaller volume.

[0094] Furthermore, for schemes employing multiple separately configured transmitting and receiving devices, it is necessary to first adjust the optical path of each optical channel and then perform joint debugging of multiple optical channels. In this embodiment of the invention, the transmitting device 100 and the receiving device 105 are integrated together, allowing for unified adjustment of multiple optical channels and reducing the assembly and debugging difficulty of the transmitting and receiving devices.

[0095] refer to Figure 6 The diagram shows a schematic of a lidar according to a second embodiment of the present invention. The similarities between this embodiment and the first embodiment will not be repeated. The differences between this embodiment and the first embodiment are as follows:

[0096] The beam-changing device includes a third reflector group 201, located on a second plane X2Y2 parallel to the first plane X1Y1 and corresponding to the position of the transmitting device 200, for receiving the emitted beam and deflecting the emitted beam 200 in the second direction X2 along the second plane X2Y2. The third reflector group 201 consists of reflectors arranged side-by-side and adjacent to each other, each corresponding to receive the emitted beam from the transmitting device 200.

[0097] The fourth reflector group 215 includes a plurality of second reflectors 205 located on the second plane X2Y2 and separated. The position of each second reflector 205 on the first plane X1Y1 corresponds to the position of each of the reflective units (not shown). Here, "corresponding" means that the second reflector 205 can reflect the emitted beam toward the first plane X1Y1, and the position of the emitted beam when it reaches the first plane X1Y1 is located on the optical axis of each optical channel. It is used to receive the emitted beam reflected by the third reflector group 201, so that the emitted beam is deflected in a direction Z perpendicular to the first plane X1Y1.

[0098] In this embodiment, the second reflector 205 and the corresponding reflectors in the third reflector group 201 are integrated into an optical element 206. The optical element 206 is disposed in the second plane X2Y2 and extends along the second direction X2. The emitted light beam propagates along the second direction X2 in the optical element 206 based on the principle of total internal reflection and is reflected when it reaches the second reflector 205. On the one hand, the optical element 206 increases the distance between the optical paths of each optical channel in this embodiment of the invention. On the other hand, the optical element 206 in this embodiment of the invention also improves the utilization rate of the emitted light beam.

[0099] The fifth reflector group 213 includes a plurality of third reflectors 203 located on the first plane X1Y1 and corresponding to the position of the second reflector 205. Here, "corresponding" means that the third reflector 203 is located on the first plane X1Y1 at a position that can reflect the emitted light beam. Specifically, the plurality of third reflectors 203 are staggered in the first direction Y1 to deflect the emitted light beam in the first plane X1Y1 toward the first direction Y1.

[0100] The beam changing device of the present invention has only a third reflecting mirror arranged in the first plane X1Y1, and the other optical elements are all located in the space perpendicular to the first plane X1Y1. This makes fuller use of the three-dimensional space, reduces interference to the optical path of the first plane X1Y1, and improves the flexibility of the arrangement of optical elements in the first plane X1Y1.

[0101] In this embodiment of the invention, the beam alteration device works in conjunction with the third reflector group 201, the fourth reflector group 215, and the fifth reflector group 213 to increase the distance between the optical axes of the multiple emitted beams. Furthermore, based on the reversibility of the optical path, when the echo beams return to the receiving device 200 sequentially via the fifth reflector group 213, the fourth reflector group 215, and the third reflector group 201, the distance between the multiple echo beams can be reduced.

[0102] The multi-path optical channel further includes: a plurality of third convex lenses 204, respectively located between the reflection unit (not shown) and the beam changing device; a plurality of fourth convex lenses 202, respectively located between the second reflector 205 and the third reflector 203; the diameter of the fourth convex lens 202 is smaller than the diameter of the third convex lens 204.

[0103] The fourth convex lens 202 can expand the emitted beam and compress the echo beam, further improving the compactness of the lidar transmitting and receiving devices.

[0104] In this embodiment of the invention, the third reflecting mirror 203 is used to deflect the emitted beam in the first direction Y1 and then project it onto the third convex lens 204.

[0105] To further reduce the size of the transmitting and receiving devices, reference Figure 7 A schematic diagram of the receiving device in a lidar according to a third embodiment of the present invention is shown. The lidar according to this embodiment includes:

[0106] Lens array 301 is located between the beam splitter (not shown) and the receiving unit array 300. Lens array 301 includes multiple lenses 302 with different eccentricities, which are used to deflect part or all of the echo beams to reduce the distance between the multiple echo beams.

[0107] This allows the receiver array 300 to detect multiple echo beams with a smaller size, thereby reducing the size of the lidar.

[0108] By giving the lenses 302 on the lens array 301 different shapes, the eccentricity of the lenses 302 is changed, thereby altering the optical axis of the lenses 302. Specifically, the echo beams received by the lens array 301 include: a first echo beam close to the receiving unit array and a second echo beam farther from the receiving unit array relative to the first echo beam, wherein the lens eccentricity corresponding to the second echo beam is greater than that corresponding to the first echo beam.

[0109] like Figure 7 As shown, for echo beams B and C near the center of the receiving unit array 300, the lens 302 on the lens array 301 is not eccentrically set, so that echo beams B and C are projected onto the receiving unit array 300 along the original optical path. However, for echo beams A and D far from the center of the receiving unit array 300, the lens 302 on the lens array 301 is eccentrically set to deflect echo beams A and D toward the receiving unit array 300.

[0110] In application, the optical path offset can be set according to the actual receiving unit array. For example, by setting the offset, the offset of echo beams A and D can be within the range of 1 to 5 mm. During the design, the light spots formed by echo beams A, B, C, and D on the receiving unit array 300 do not overlap, so as to realize the detection of each light path. For example, the light spot spacing between adjacent echo beams on the receiving unit array 300 is within the range of 0.3 to 5 mm.

[0111] refer to Figure 8 This diagram illustrates a lidar receiving device according to a fourth embodiment of the present invention. This embodiment is similar to... Figure 7 The difference in the third embodiment shown is that the lidar further includes: a prism array 401 located between the beam splitter (not shown) and the receiving unit array 400, the prism array 401 including a plurality of prisms 402 with different wedge angles, used to deflect the echo beam to increase the distance between the multiple echo beams; and a converging lens 403 located between the prism array 401 and the receiving unit array 400, used to converge the deflected echo beam.

[0112] In this embodiment, the optical axes of the various echo beams are first deparallelized using a prism array 401, and then converged using a converging lens 403. The receiving unit array 400 is located at the focal point of the converging lens 403. When adjusting the optical path offset, with the converging lens 403 unchanged, a smaller prism wedge angle β results in a smaller spacing between the multiple echo beams, while with the prism 402 unchanged, a larger focal length of the converging lens results in a larger spacing between the multiple echo beams.

[0113] Therefore, this embodiment allows for more flexible adjustment of the spacing between echo beams using prism 402 and converging lens 403. This satisfies the requirement for a compact device structure while also allowing adjustment of the spacing between adjacent light spots on the receiving unit array. Consequently, it can adapt to the design requirements of different lidar systems.

[0114] like Figure 8 As shown, the prism array 401 receives echo beams including first echo beams B' and C' close to the center of the receiving unit array 400, and second echo beams A' and D' far away from the receiving unit array 400 relative to the first echo beams B' and C'. The prism wedge angle β corresponding to the second echo beams A' and D' is set to be greater than the prism wedge angle β corresponding to the first echo beams B' and C', so that the optical path deflection of the second echo beams A' and D' is greater than that of the first echo beams B' and C', thereby making the light spots formed on the receiving unit array 400 after the four echo beams pass through the converging lens 403 not overlap.

[0115] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A laser radar comprising a plurality of optical channels and a scanning device; said plurality of optical channels providing a plurality of outgoing light beams which converge at said scanning device; said scanning device being adapted to receive said plurality of outgoing light beams and to scan them out, and to receive a plurality of return light beams formed by said plurality of outgoing light beams after reflection from a target object and to direct said plurality of return light beams into said plurality of optical channels for detection; characterized in that, The multiple optical channels comprise a first optical channel and a second optical channel, wherein the first optical channel and the second optical channel respectively comprise: a transmitting device for providing a transmitting light beam; a reflecting unit for reflecting the transmitting light beam to form an outgoing light converging on the scanning device, and for receiving the echo light beam scanned by the scanning device to reflect the echo light beam; a receiving device for detecting the echo light beam; a beam changing device located on the light paths between the transmitting device and the reflecting unit and between the reflecting unit and the receiving device, for increasing the distance between the multiple transmitting light beams and for decreasing the distance between the multiple echo light beams; wherein the first optical channel and the second optical channel are independent of each other, and the reflecting unit of the first optical channel and the reflecting unit of the second optical channel are separated from each other.

2. The lidar of claim 1, wherein, The beam changing device is further configured to expand the transmitting light beam and compress the echo light beam.

3. The lidar of claim 1, wherein, In the multiple optical channels, a plane from the beam changing device to the reflecting unit is a first plane, in the first plane, a direction of the light path of the transmitting light beam from the beam changing device to the reflecting unit is a first direction, and a direction perpendicular to the first direction is a second direction; the transmitting device provides the transmitting light beam along a direction perpendicular to the first plane; the receiving device detects the echo light beam returned along a direction perpendicular to the first plane.

4. The lidar of claim 3, wherein, The beam changing device comprises: a first mirror group located in the first plane and corresponding to the position of the transmitting device, configured to receive the transmitting light beam provided by the transmitting device and deflect the transmitting light beam to the second direction; a second mirror group comprising multiple separated first mirrors, each first mirror corresponding to the position of the reflecting unit, configured to receive the transmitting light beam reflected by the first mirror group and deflect the transmitting light beam to the first direction.

5. The lidar of claim 4, wherein, The laser radar further comprises multiple first convex lenses respectively located between the reflecting unit and the beam changing device. The beam changing device further comprises multiple second convex lenses respectively located between the first mirror group and the second mirror group, wherein the diameter of the second convex lens is smaller than the diameter of the first convex lens.

6. The lidar of claim 5, wherein, The first mirror is configured to project the transmitting light beam deflected to the first direction to the first convex lens.

7. The lidar of claim 3, wherein, The beam changing device comprises: a third mirror group located in a second plane parallel to the first plane and corresponding to the position of the transmitting device, configured to receive the transmitting light beam and deflect the transmitting light beam to the second direction in the second plane; a fourth mirror group comprising multiple separated second mirrors located in the second plane, each second mirror corresponding to the position of each reflecting unit in the first plane, configured to receive the transmitting light beam reflected by the third mirror group and deflect the transmitting light beam to a direction perpendicular to the first plane. A fifth mirror group includes a plurality of third mirrors located in the first plane and corresponding to positions of the second mirrors, the plurality of third mirrors being arranged in the first direction with a positional offset, for deflecting the emitted light beams in the first plane in the first direction.

8. The lidar of claim 7, wherein, The multi-path optical channel further includes: a plurality of third convex lenses respectively located between the reflecting units and the beam changing device; A plurality of fourth convex lenses are respectively located between the second mirrors and the third mirrors, and a diameter of the fourth convex lens is smaller than a diameter of the third convex lens.

9. The lidar of claim 8, wherein, The third mirrors are configured to project the emitted light beams after being deflected in the first direction to the third convex lenses.

10. The lidar of any one of claims 1-9, wherein, The emitting device includes: an array of emitting units configured to provide the multi-path emitted light beams. The receiving device includes: an array of receiving units configured to detect the multi-path returned light beams.

11. The lidar of claim 10, wherein, The laser radar further includes: a light splitting device configured to transmit the emitted light beams provided by the array of emitting units and reflect the returned light beams to the array of receiving units, or configured to reflect the emitted light beams provided by the array of emitting units and transmit the returned light beams to the array of receiving units.

12. The lidar of claim 11, wherein, The light splitting device includes: a polarization splitting device configured to transmit light of one polarization state and reflect light of another polarization state; and a wave plate configured to adjust polarization states of the emitted light beams and the returned light beams.

13. The lidar of claim 12, wherein, The polarization splitting device is a polarization splitting prism or a polarization splitting film.

14. The lidar of claim 11, wherein, The laser radar further includes: a lens array located between the light splitting device and the array of receiving units, the lens array including a plurality of lenses with different eccentricities, for deflecting part or all of the returned light beams to reduce distances between the multi-path returned light beams.

15. The lidar of claim 14, wherein, The returned light beams received by the lens array include: first returned light beams close to the array of receiving units and second returned light beams away from the array of receiving units relative to the first returned light beams, and the second returned light beams correspond to lenses with larger eccentricities than the first returned light beams.

16. The lidar of claim 11, wherein, The laser radar further includes: a prism array located between the light splitting device and the array of receiving units, the prism array including a plurality of prisms with different wedge angles, for deflecting the returned light beams to increase distances between the multi-path returned light beams. A converging lens is located between the prism array and the array of receiving units, for converging the deflected returned light beams.

17. The lidar of claim 16, wherein, The returned light beams received by the prism array include: first returned light beams close to the array of receiving units and second returned light beams away from the array of receiving units relative to the first returned light beams, and the second returned light beams correspond to prisms with larger wedge angles than the first returned light beams.

18. The lidar of any one of claims 1-9, wherein, The multi-path optical channel further includes: a correction unit configured to make a plurality of light spots formed by exiting light of the multi-path optical channel parallel to each other in a specific direction.

19. The lidar of claim 18, wherein, The correction unit is a Dove prism located between the emitting device and the beam changing device.

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