LiDAR

Abstract

The present invention provides a lidar, comprising: a plurality of optical channels, where each optical channel includes: a transmitting device for providing transmitted light, a reflecting device for reflecting the transmitted light to form reflected light; a scanning device for scanning and emitting the reflected light corresponding to the plurality of optical channels to form emitted light for detecting a target object; and the plurality of light spots formed by the emitted light of the plurality of optical channels are parallel to each other in a specific direction. The lidar of the present invention improves the spatial arrangement of the emitted light spots of the plurality of optical channels and increases the coverage range of the emitted light spots by enabling the plurality of light spots formed by the emitted light to be parallel to each other, that is, there is no relative rotational angle between the emitted light spots of the plurality of optical channels, thereby improving the detection coverage rate of the target object.

Description

Technical Field

[0001] The present invention relates to the field of laser detection, and particularly to a scanning lidar. Background Art

[0002] Lidar (Light Detection and Ranging) undertakes important tasks such as curb detection, obstacle recognition, and Simultaneous Localization and Mapping (SLAM) in autonomous driving.

[0003] Specifically, a lidar system includes a laser emission system and an optical reception system. The laser emission system includes an optical emission unit that generates an emitted light pulse. The emitted light pulse is incident on a target object, reflected, and generates an echo beam. Finally, the echo beam is received by the optical reception system. The reception system accurately measures the propagation time of the incident light pulse from emission to reflection back. Since the light pulse propagates at the speed of light, and the speed of light is known, the propagation time can be converted into a measurement of distance.

[0004] Lidar can accurately measure the target position (distance and angle), motion state (speed, vibration, and attitude), and shape, and detect, identify, distinguish, and track targets. Due to advantages such as fast measurement speed, high accuracy, and long ranging distance, lidar has been widely used in driverless vehicles.

[0005] However, in the disclosed technologies, lidar has the problem of low detection coverage. Summary of the Invention

[0006] The problem solved by the present invention is to provide a lidar to improve the detection coverage.

[0007] The technical solution of the present invention provides a lidar, including: a plurality of optical channels, where each optical channel includes: a transmitting device for providing transmitted light, a reflecting device for reflecting the transmitted light to form reflected light; a scanning device for scanning and emitting the reflected light corresponding to the plurality of optical channels to form emitted light for detecting a target object; the plurality of light spots formed by the emitted light of the plurality of optical channels are parallel to each other in a specific direction.

[0008] Optionally, the light spot is an elliptical light spot, and the specific direction is the slow axis direction of the elliptical light spot.

[0009] Optionally, the reflecting device is an independent reflecting mirror in each optical channel, and the optical channel further includes: a Dove prism located on the optical path between the transmitting device and the reflecting device.

[0010] Optionally, the rotation angle of the Dove prism around the optical axis is set such that the light spots formed by the emitted light corresponding to the plurality of optical channels are parallel to each other.

[0011] Optionally, the optical channel includes: a first optical channel incident on the scanning device at a first incident angle; and a second optical channel incident on the scanning device at a second incident angle, where the first incident angle is greater than the second incident angle; the rotation angle of the Dove prism around the optical axis in the first optical channel is greater than the rotation angle of the Dove prism around the optical axis in the second optical channel.

[0012] Optionally, the reflection device is an independent mirror in each optical channel, and the light output angle of the emission device is set such that the spots formed by the emitted light corresponding to the multiple optical channels are parallel to each other.

[0013] Optionally, the optical channel includes: a first optical channel incident on the scanning device at a first incident angle; and a second optical channel incident on the scanning device at a second incident angle, where the first incident angle is greater than the second incident angle; the rotation angle of the emission device in the first optical channel is greater than the rotation angle of the emission device in the second optical channel.

[0014] Optionally, the reflection device is a shared mirror in each optical channel.

[0015] Optionally, the emitted light provided by the emission device of each optical channel is on the same plane, and the angle between the normal of the reflection device and the plane is the same.

[0016] Optionally, the emission devices of the optical channels provide emitted light in different directions, and the multiple emitted lights converge on the mirror.

[0017] Optionally, in each optical channel, an optical path changing device is further provided on the optical path between the emission device and the reflection device, for converging the multiple emitted lights to the reflection device in different directions.

[0018] Optionally, the emission devices of each optical channel provide parallel emitted light.

[0019] Optionally, the optical path changing device is a wedge prism, and the wedge angle of the wedge prism is set such that the multiple emitted lights converge to the reflection device in different directions.

[0020] Optionally, the emission device includes an edge-emitting laser.

[0021] Optionally, the optical channel further includes: a beam splitting device, which is used to transmit the emitted light provided by the emission device and also used to reflect the echo beam, or used to reflect the emitted light provided by the emission device and also used to transmit the echo beam.

[0022] Optionally, the optical channel further includes: a lens, which is used to converge the emitted light to the reflection device.

[0023] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0024] In the lidar according to the embodiment of the present invention, the multiple light spots formed by the emitted light can be parallel to each other, that is, there is no relative rotation angle between the emitted light spots of multiple optical channels, thereby improving the spatial arrangement of the emitted light spots of multiple optical channels, increasing the coverage range of the emitted light spots, and further improving the detection coverage rate of the target object. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic optical path diagram of a lidar in the disclosed technology;

[0026] Figure 2 is Figure 1 a schematic diagram of the light spot of the emitted light of the lidar in

[0027] Figure 3 is a schematic optical path diagram of the lidar according to the first embodiment of the present invention;

[0028] Figure 4 is Figure 3 a schematic diagram of a Dove prism in

[0029] Figure 5 is Figure 3 a schematic principle diagram of the Dove prism in

[0030] Figure 6 is Figure 3 a schematic diagram of the light spot of the emitted light of the lidar in

[0031] Figure 7 is Figure 3 a schematic diagram of another light spot of the emitted light of the lidar in

[0032] Figure 8 is a schematic optical path diagram of the lidar according to the second embodiment of the present invention;

[0033] Figure 9 is a schematic optical path diagram of the lidar according to the third embodiment of the present invention;

[0034] Figure 10 is a schematic optical path diagram of the lidar according to the fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] As described in the background art, the light emitting unit of the lidar in the disclosed technology has the problem of low detection coverage rate. Combining Figure 1 with the schematic optical path diagram of a lidar in the disclosed technology shown in Figure 2 and the schematic diagram of the light spot, the reason for the problem is analyzed. It should be noted that, for the sake of simplicity and clarity, the schematic diagram is described by taking a four-channel optical path as an example.

[0036] As Figure 1 shown, the lidar includes multiple optical channels a, b, c, d and a scanning device 14. Among them, each of the optical channels includes: a light source 10 for providing emitted light, a beam splitter 11 for transmitting the emitted light, a lens 12 for converging the emitted light, and a mirror 13 for reflecting the emitted light to the scanning device 14. The scanning device 14 scans and emits the multiple outgoing lights to form an outgoing light E for detecting a target object. The scanning device 14 also receives an echo beam formed after the outgoing light E is reflected by the target object, scans the echo beam, and makes the echo beam enter the multiple optical channels for detection respectively. Specifically, in each optical channel, the echo beam is reflected by the beam splitter 11 and projected onto a detector 15 to realize the detection of the echo beam.

[0037] In practical applications, the light source 10 can be an edge emitting laser (EEL). Correspondingly, as Figure 2 shown, the outgoing light spot 16 formed by the outgoing light E is elliptical.

[0038] It should be noted that in other embodiments, the light source 10 can also be a vertical-cavity surface-emitting laser (VCSEL) for emitting a circular light spot. When the circular light spot passes through the optical devices in the optical channel, due to aberrations (such as astigmatism, distortion, etc.), it becomes an elliptical light spot or an approximately elliptical light spot when emitted.

[0039] By comparing the outgoing light spots 16 corresponding to the optical channels a, b, c, d, it can be found that the extension direction of the major axis of the elliptical outgoing light spot 16 is different. That is to say, there is a problem of light spot rotation between different optical channels a, b, c, d, resulting in a reduced light spot coverage range when the outgoing lights of each optical channel are scanned, thus affecting the detection coverage rate of the lidar.

[0040] After analysis, the problem of the light spot rotation lies in that the mirrors in each optical channel have different spatial angles. As Figure 2 shown in a and d, when the spatial incident angle (i.e., the angle between the optical axis of the emitted light and the normal of the mirror) is larger, the rotation angle of the light spot is larger. In addition, in the optical channels distributed on the opposite side of the scanning device, the rotation directions of the outgoing light spots are also different.

[0041] To solve the problem of spot rotation and improve the detection coverage rate, an embodiment of the present invention provides a lidar, which includes multiple optical channels. The optical channels include: a transmitting device for providing transmitted light; a reflecting device for reflecting the transmitted light to form reflected light; a scanning device for scanning and emitting the reflected light corresponding to the multiple optical channels to form emitted light for detecting a target object; and the multiple spots formed by the emitted light of the multiple optical channels are parallel to each other in a specific direction. The lidar according to the embodiment of the present invention enables the multiple spots formed by the emitted light to be parallel to each other, that is, there is no relative rotation angle between the emitted spots of the multiple optical channels, thereby improving the spatial arrangement of the emitted spots of the multiple channels, increasing the coverage range of the emitted spots, and further improving the detection coverage rate of the target object.

[0042] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following will describe the specific embodiments of the present invention in detail with reference to the accompanying drawings.

[0043] Reference Figure 3 , which shows the optical path schematic diagram of the lidar according to the first embodiment of the present invention. The lidar according to the embodiment of the present invention is a scanning lidar, including:

[0044] Multiple optical channels for providing multiple beams for detection. It should be noted that, for example, three optical channels a, b, and c are taken as examples here. In other embodiments, the number of multiple optical channels can also be two, four, five, etc.

[0045] Specifically, each optical channel includes:

[0046] A transmitting device 100 for providing transmitted light. In this embodiment, the transmitted lights provided by the transmitting devices of the multiple optical channels are parallel to each other.

[0047] Specifically, the transmitting device 100 uses an EEL. The EEL has the characteristics of miniaturization, stable coherent light, and narrow emission wavelength, and is thus widely used in lidars.

[0048] In this embodiment, the EEL is a laser light source, and the spot formed by the emitted light corresponding to the EEL is an elliptical spot.

[0049] The transmitting device 100 may include multiple EELs. Preferably, the multiple EELs can be arranged in a one-dimensional or two-dimensional manner.

[0050] A beam splitter 101 for reflecting the transmitted light provided by the transmitting device 100 and for transmitting the echo beam to the receiving unit for detection. Alternatively, the beam splitter 101 is for transmitting the transmitted light provided by the transmitting device 100 and for reflecting the echo beam to the receiving unit for detection.

[0051] The beam splitter 101 can make the optical paths of the emitted light and the echo beam share most of the optical elements, thereby improving the structural compactness of the lidar.

[0052] Specifically, the beam splitter 101 includes: a polarized beam splitter prism (Polarized Beam Splitter, PBS) or a polarized beam splitting film, a quarter-wave plate, and the like.

[0053] As Figure 3 shown, the optical channel further includes: a Dove prism 106 on the optical paths of the transmitting device 100 and the reflecting device 103, which is used to correct the spot formed by the outgoing light, so that the spots corresponding to the multiple optical channels are parallel to each other in a specific direction. Thus, there is no relative rotation angle between the spots of the multiple optical channels, increasing the coverage range of the outgoing spot, and thus being beneficial to improving the detection coverage rate.

[0054] It should be noted that in the embodiment of the present invention, the spot is an elliptical spot, and the specific direction is the slow axis direction of the elliptical spot (i.e., the long axis direction of the ellipse). Preferably, the slow axis direction is the vertical direction, and the spots of each optical channel are parallel to each other in the slow axis direction. In this way, multiple spots are parallel in the extending direction of the maximum size of the spot, increasing the coverage range of the outgoing spot, and can further improve the detection coverage rate.

[0055] With reference to Figure 4 , the Dove prism uses the critical angle principle to achieve total internal reflection inside. On the premise that the direction of the incident light P remains unchanged, when the Dove prism 106 rotates by an angle θ around its optical axis, the rotation angle of the outgoing light B is 2θ (i.e., the rotation angle of the outgoing light is twice the rotation angle of the prism itself).

[0056] For example, referring to Figure 5 A-5C, the optical path diagrams of the Dove prism at different rotation angles are respectively shown. Relative to Figure 3 A, when the Dove prism in Figure 5 B rotates by θ = 45 degrees around its optical axis, the outgoing light rotates by 2θ = 90 degrees with respect to the prism itself (the rotation angle with respect to the Y axis). Similarly, relative to Figure 5 A, when the Dove prism in Figure 5 A, when the Dove prism in Figure 5 C rotates by θ = 90 degrees around its optical axis, the outgoing light rotates by 2θ = 180 degrees with respect to the prism itself (the rotation angle with respect to the Y axis).

[0057] Since the multiple optical channels are distributed at different positions of the scanning device, therefore, the spatial incident angles of each optical path are different, and correspondingly, the spot rotation angles that need to be corrected are also different.

[0058] With reference to Figure 6, the rotation angle of the Dove prism 106 around its optical axis is set such that the spots formed by the outgoing light corresponding to multiple optical channels are parallel to each other.

[0059] Combined with reference Figures 3 to 6 , the lidar of this embodiment includes three optical channels a, b, and c. Among them, the second optical channel b is located at the central position, and its reflected light is incident on the scanning device at a second incident angle. The first optical channel a is located on one side of the second optical channel b, and the third optical channel c is located on the other side of the second optical channel b away from the first optical channel a. And in this embodiment, the first optical channel a and the third optical channel c are symmetrically distributed on both sides of the second optical channel b. Correspondingly, the reflected light of the first optical channel a (or the third optical channel c) is incident on the scanning device at a first incident angle, and the first incident angle is greater than the second incident angle. Because, the larger the incident angle, the larger the rotation angle of the spot, that is, the larger the angle that the Dove prism needs to correct. Correspondingly, the rotation angle of the Dove prism around its optical axis in the first optical channel a or the third optical channel c is greater than the rotation angle of the Dove prism around its optical axis in the second optical channel b.

[0060] In practical applications, the reference direction can be defined first, and then the correction angles of each optical channel can be obtained based on the reference direction.

[0061] In this embodiment, taking the vertical direction as the reference direction, the slow axis direction of the outgoing spot is corrected and adjusted to the vertical direction. In this embodiment, the Dove prisms in the first optical channel a, the second optical channel b, and the third optical channel c are adjusted respectively, so that the slow axes (i.e., the major axes of the ellipse) of the outgoing spots of the first optical channel a, the second optical channel b, and the third optical channel c are all parallel along the vertical direction. Specifically, taking the angle between the slow axis direction of the elliptical spot when the Dove prism is not set in the first optical channel a, the second optical channel b, and the third optical channel c and the vertical direction as the correction angle, and then based on the angle that needs to be corrected, the rotation angle of the Dove prism around the optical axis on each optical channel is adjusted, so that the slow axes of the respective elliptical spots 1, 2, and 3 of the first optical channel a, the second optical channel b, and the third optical channel c are parallel along the vertical direction (as Figure 6 shown).

[0062] It should be noted that since the rotation angle of the outgoing light B of the Dove prism is twice the rotation angle of the incident light P around its optical axis, when adjusting the Dove prism based on the correction angle, the rotation angle of the incident light P of the Dove prism is set to half of the correction angle.

[0063] The lens 102 is used to converge the emitted light to the reflection device 103, improving the light utilization rate of the emitted light.

[0064] Such as Figure 3As shown, the lens 102 is located between the beam splitter 101 and the mirror, and is used to converge the emitted light passing through the beam splitter 101 to the mirror. Specifically, the lens 102 is a convex lens.

[0065] It should be noted that in this embodiment, the Dove prism 106 is located between the beam splitter 101 and the lens 102, thus having a better optical path compactness. In other embodiments, the Dove prism 106 can also be located between the lens 102 and the reflection device 103.

[0066] The reflection device 103 is used to change the propagation direction of light, so that the emitted light is reflected to form a reflected light, and the propagation direction of the reflected light is towards the scanning device 104 and converges at the position of the scanning device 104.

[0067] In this embodiment, the reflection device 103 includes: mirrors that are located in each optical channel and are independent of each other. Since the multiple optical channels are distributed at different positions of the scanning device 104, the emitted light provided by the emitting device 100 in this embodiment is parallel to each other. In order to make the reflected light of each optical channel converge at the scanning device 104, the mirrors of each optical channel have different spatial arrangement positions, that is to say, the mirrors of each optical channel have normal directions with different spatial angles.

[0068] The scanning device 104 is used to scan and emit the reflected light corresponding to the multiple optical channels to form an emitted light for detecting the target object.

[0069] Specifically, the scanning device 104 can be a scanning galvanometer, which scans and reflects the emitted light of multiple optical channels to form an emitted light for detecting the target object. The emitted light is reflected by the target object to form an echo beam, and the echo beam enters each optical channel through the scanning of the scanning device 104. The beam splitter 101 of each optical channel projects the echo beam to the receiving unit 105.

[0070] The receiving unit 105 is usually a photodetector, and the detection of the target object by the lidar is realized by detecting the echo beam.

[0071] In the embodiment of the lidar of the present invention, a Dove prism is used to correct the spot rotation caused by different normal directions of the mirrors in each optical channel, so that the spots formed by the outgoing light are parallel to each other in a specific direction, thereby optimizing the spatial arrangement of multiple outgoing spots, increasing the coverage range of the outgoing spots, and improving the detection coverage rate of the lidar. In addition, by adjusting the spot angle with a Dove prism, it is not necessary to adjust the angles of the transmitting device (for example, a laser) and the receiving device (for example, a photodetector). Lasers and photodetectors are both precision instruments, and their assembly and position correction are of a certain degree of difficulty. In the embodiment of the present invention, the spot is adjusted by a simple optical element (for example, a Dove prism), reducing the limitation of spot adjustment on the spatial arrangement of the laser and the detector, which is beneficial to the installation and adjustment of the laser and the detector.

[0072] It should be noted that in Figure 6 the shown spot schematic diagram, the spots of the outgoing light of multiple optical channels are parallel to each other in the vertical direction. In the embodiment of the lidar of the present invention, the spots of the outgoing light of multiple optical channels are parallel to each other in a specific direction. Here, the specific direction means parallel in any specific direction, and also includes Figure 7 as shown in, the spots 1', 2', 3' of the outgoing light corresponding to multiple optical channels a', b', c' are parallel to each other in a direction with a certain inclination angle with respect to the vertical direction, increasing the coverage range of the outgoing spots. Such spots of the outgoing light also improve the detection coverage rate of the lidar. In practical applications, a direction with a certain inclination angle with respect to the vertical direction can be used as the reference direction, and the correction angles corresponding to each optical path a', b', c' can be obtained respectively to make the spots 1', 2', 3' of each outgoing light parallel to each other.

[0073] Referring to Figure 8 , the optical path schematic diagram of the lidar according to the second embodiment of the present invention is shown. In this embodiment, multiple optical channels are described by taking four optical channels a, b, c, d as an example.

[0074] The same parts of the embodiment of the present invention and the first embodiment will not be described in detail. The difference is that in this embodiment, a Dove prism is not used to adjust the rotation angle of the outgoing spot, but by setting the outgoing light angle of the transmitting device 200, the outgoing spots corresponding to the multiple optical channels are made parallel to each other.

[0075] Specifically, as Figure 8As shown in the figure, the reflection device 203 in this embodiment includes: mirrors located in each optical channel, and the mirrors are independent of each other. The normal directions of the mirrors in each optical channel have different spatial angles. Therefore, before the correction of the spot angle, there is a rotation angle between the outgoing spots of each optical channel. The lidar in this embodiment sets the outgoing light angle of the emission device 200 so that the spots formed by the outgoing light corresponding to the multiple optical channels are parallel to each other.

[0076] In this embodiment, the emission device 200 is a laser or a laser array, both of which include an outgoing light surface. By adjusting the relative position of the outgoing light surface of the laser or the laser array and the mirror, the correction of the rotation angle of the outgoing spot is realized by adjusting the angle of the outgoing light surface, and further the purpose of making the spots parallel to each other is achieved.

[0077] Specifically, before adjusting the angle of the outgoing light surface, the angle to be corrected can be determined according to the direction of the outgoing spot, and the rotation angles β1, β2, β3, and β4 of the outgoing light surface of the laser are set based on the angle to be corrected for correcting the spot rotation. In this embodiment, the rotation angle of the outgoing light surface is the same as the angle to be corrected.

[0078] As Figure 8 shown, the four optical channels a, b, c, and d are arranged symmetrically on the return light path of the scanning device. Specifically, the second optical channel b and the third optical channel c are symmetrically arranged at positions close to the scanning device. The first optical channel a is located at a position far from the scanning device relative to the second optical channel b, and the fourth optical channel d is located at a position far from the scanning device relative to the third optical channel c. And the second optical channel b and the third optical channel c are symmetrically arranged, and the first optical channel a and the fourth optical channel d are symmetrically arranged.

[0079] Define the incident angle of the first optical channel a and the fourth optical channel d incident on the scanning device as the first incident angle, and define the incident angle of the second optical channel b and the third optical channel c incident on the scanning device as the second incident angle. Since the first optical channel a and the fourth optical channel d are relatively far from the scanning device 204, correspondingly, the first incident angle is greater than the second incident angle. The larger the incident angle, correspondingly, the larger the rotation angle of the outgoing spot. Therefore, when correcting the angle of the outgoing spot by rotating the emission device, the angle of the outgoing light surface of the emission device can be configured based on the rotation angle of the spot when the emission device is not adjusted. In this embodiment, the rotation angles β1 and β4 of the emission device in the first optical channel a and the fourth optical channel d are greater than the rotation angles β2 and β3 of the emission device in the second optical channel b and the third optical channel c.

[0080] Continue to refer to Figure 8, facing the direction of the paper surface (hereinafter, both the clockwise and counterclockwise directions are facing the paper surface), the first optical channel a and the second optical channel b are located on the left side of the scanning device 204, and the third optical channel c and the fourth optical channel d are located on the right side of the scanning device 204. Therefore, the rotation directions of the outgoing light spots of the first optical channel a, the second optical channel b, the third optical channel c, and the fourth optical channel d are also different. Correspondingly, compared with the light-emitting surface before correction shown by the dashed line Figure 8 In this embodiment, the light-emitting surfaces of the emitting devices in the first optical channel a and the second optical channel b rotate clockwise, and the third optical channel c and the fourth optical channel d rotate counterclockwise.

[0081] The beam splitting device 201, the lens 202, and the receiving unit 205 of the lidar according to the embodiment of the present invention refer to the description of the first embodiment and will not be elaborated here.

[0082] The lidar of this embodiment corrects the rotation angle of the outgoing light spot by changing the angle of the light-emitting direction of the emitting device, without the need to rely on other optical elements, which can reduce the cost of the lidar.

[0083] Refer to Figure 9 , which shows the optical path schematic diagram of the lidar according to the third embodiment of the present invention.

[0084] The same parts of the embodiment of the present invention and the first embodiment will not be elaborated. The differences are as follows: The reflection device 303 of the present invention uses a common mirror for multiple optical channels. Because multiple optical channels share the same mirror, the reflection devices 303 of each optical channel have the same normal direction, thereby reducing the problem of light spot rotation caused by different normal space angles of each mirror, so as to achieve the parallelism of the outgoing light spots in a specific direction.

[0085] As Figure 9 shown, in this embodiment, four optical channels a, b, c, and d are taken as examples for multiple optical channels. The emitted light provided by the emitting devices 300 in the four optical channels a, b, c, and d is on the same plane (paper surface), and the angle between the normal of the reflection device 303 and the plane is the same (the angle is zero here), which can further ensure that there is no rotation angle between the outgoing light spots of each optical channel, and achieve the effect that the outgoing light spots are parallel to each other in a specific direction.

[0086] In this embodiment, the first optical channel a and the fourth optical channel d are located at positions away from the scanning device relative to the second optical channel b and the third optical channel c. In order to make the reflected light of the first optical channel a and the fourth optical channel d converge to the scanning device 304, if the emitting device of the optical channel is parallel light, then relative to the optical path offset amounts γ2 and γ3 of the second optical channel b and the third optical channel c, the reflecting device 303 needs to have larger optical path offset amounts γ1 and γ4 for the first optical channel a and the fourth optical channel d. However, in this embodiment, each optical channel shares the same reflecting mirror, and the degree of change in the optical path is limited. In order to enable the reflected light to converge at the scanning device 304, it is necessary to change the optical path direction of the optical channel in advance and introduce an optical path offset amount to ensure that the reflected light of each optical channel converges at the position of the scanning device.

[0087] In addition, facing the direction of the paper surface, the first optical channel a and the second optical channel b are located on the left side of the scanning device 304, and the third optical channel c and the fourth optical channel d are located on the right side of the scanning device 304. Therefore, the rotation directions of the outgoing light spots of the first optical channel a and the second optical channel b are also different from those of the third optical channel c and the fourth optical channel d. Correspondingly, compared with Figure 9 the optical path direction when not corrected as shown by the dotted line, in this embodiment, the optical path offset amounts in the first optical channel a and the second optical channel b are offset clockwise compared with the uncorrected direction, and the optical path offset amounts in the third optical channel c and the fourth optical channel d are rotated counterclockwise compared with the uncorrected direction.

[0088] In the lidar according to the embodiment of the present invention, the beam splitting devices 301, the lenses 302, and the receiving units 305 of each optical channel are located on their respective optical paths, and the multi-optical paths are incident on the reflecting device 303 in a converging manner.

[0089] Compared with the Figure 8 embodiment, the embodiment of the present invention adopts the method of sharing the same reflecting mirror for each optical channel, thereby reducing the problem of spot rotation caused by different spatial angles of the normal lines of the reflecting mirror. Moreover, the lidar according to the embodiment of the present invention realizes the purpose of converging each optical path at the reflecting device by changing the arrangement of the optical paths, and the optical path structure is relatively simple.

[0090] In other embodiments, if the requirement for optical path compactness is not high, the emitted light provided by the emitting devices of each optical channel may not be completely parallel. For example, each optical path is generally parallel and converges toward the reflecting device. This method has lower requirements for the optical path changing device and can also achieve the purpose of solving the spot rotation in the embodiment of the present invention.

[0091] Refer to Figure 10, which shows the optical path schematic diagram of the lidar according to the fourth embodiment of the present invention. The similarities between the lidar according to the embodiment of the present invention and the third embodiment are that the reflecting device 403 also uses a mirror shared by multiple optical channels to solve the problem of the rotation of the outgoing light spot.

[0092] The differences of the embodiment of the present invention are as follows: the transmitting devices 400 of each optical channel provide parallel transmitting light, and an optical path changing device is arranged on each optical channel to adjust the offset amount of each optical path.

[0093] Specifically, as Figure 10 shown, in this embodiment, there are four optical channels a, b, c, and d for the multiple optical channels, and the first optical channel a and the fourth optical channel d are located at positions away from the scanning device relative to the second optical channel b and the third optical channel c. In order to make the reflected light of the first optical channel a, the fourth optical channel d and the second optical channel b, the third optical channel c converge to the scanning device 404, the reflecting device 403 needs to have a larger optical path offset amount for the first optical channel a and the fourth optical channel d relative to the second optical channel b and the third optical channel c. In addition, the first optical channel a, the second optical channel b and the third optical channel c, the fourth optical channel d are distributed on opposite sides of the reflecting device 403, and the directions of the optical path offset are also different. Therefore, in the embodiment of the present invention, different optical path changing devices are respectively arranged for the optical channels a, b, c, and d to respectively perform corresponding adjustments according to the requirements of each optical path for the optical path offset amount and the optical path offset direction.

[0094] In this embodiment, the optical path changing device 406 is a wedge prism, and the wedge angle of the wedge prism is set so that the multiple transmitting lights converge to the reflecting device in different directions. Specifically, the larger the wedge angle of the wedge prism, the larger the optical path offset amount that the wedge prism can change; the outgoing light on the wedge prism is deflected and emitted in the direction of the wedge angle.

[0095] Therefore, in this embodiment, wedge prisms with larger wedge angles are arranged on the first optical channel a and the fourth optical channel d, while wedge prisms with smaller wedge angles are arranged on the second optical channel b and the third optical channel c, so as to meet the adjustment requirements of each optical channel for the optical path offset amount. Specifically, the wedge prisms of the first optical channel a and the fourth optical channel d change the optical path by larger angles δ1 and δ4, and the wedge prisms in the second optical channel b and the third optical channel c change the optical path by smaller angles δ2 and δ3.

[0096] In addition, the wedge angle directions of the wedge prisms in the first optical channel a, the second optical channel b, the third optical channel c, and the fourth optical channel d also correspondingly point to the reflection device 403, so as to meet the adjustment requirements of the optical path offset directions of each optical channel. Specifically, the first optical channel a, the second optical channel b, the third optical channel c, and the fourth optical channel d are distributed on opposite sides of the reflection device 403. By setting the wedge angle directions of the wedge prisms to correspondingly point to the reflection device 403, the optical path offset amounts in the first optical channel a and the second optical channel b are offset counterclockwise relative to the uncorrected direction, and the optical path offset amounts in the third optical channel c and the fourth optical channel d are rotated clockwise relative to the uncorrected direction.

[0097] In this embodiment, by setting the optical path changing device, the emission devices 400 of each optical channel can provide parallel emission light, and finally converge at the scanning device 404, thereby improving the optical path compactness of the lidar.

[0098] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims. Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. A lidar, characterized in that, Comprising: Multiple optical channels, including a first optical channel, a second optical channel, a third optical channel, and a fourth optical channel, each of the multiple optical channels comprising: A transmitting device for providing transmitted light; and A reflecting device including a reflecting mirror for reflecting the transmitted light to form reflected light; A scanning device for scanning and emitting the reflected light emitted from the multiple optical channels to form emitted light for detecting a target object; Wherein, the multiple reflecting mirrors in the multiple optical channels are independent of each other, and the normal directions of the multiple reflecting mirrors have different spatial angles, such that the propagation direction of the reflected light faces the scanning device; The second optical channel and the third optical channel are located at positions close to the scanning device and are symmetrically arranged with respect to the scanning device, The first optical channel is located at a position farther from the scanning device than the second optical channel, The fourth optical channel is located at a position farther from the scanning device than the third optical channel, and The first optical channel and the fourth optical channel are symmetrically arranged with respect to the scanning device; The multiple light spots formed by the emitted light from the multiple optical channels are parallel to each other in a specific direction.

2. The lidar according to claim 1, characterized in that, The light spot is an elliptical light spot, and the specific direction is the slow axis direction of the elliptical light spot.

3. The lidar according to claim 1, characterized in that, The optical channel further includes: a Dove prism located on the optical path between the transmitting device and the reflecting device.

4. The lidar according to claim 3, wherein, The rotation angle of the Dove prism around the optical axis is set such that the light spots formed by the emitted light corresponding to the multiple optical channels are parallel to each other.

5. The lidar according to claim 4, wherein The incident angle of the reflected light emitted from the first optical channel incident on the scanning device is a first incident angle, and the incident angle of the reflected light emitted from the second optical channel incident on the scanning device is a second incident angle, and the first incident angle is greater than the second incident angle; The rotation angle of the Dove prism in the first optical channel around its own optical axis during installation is greater than the rotation angle of the Dove prism in the second optical channel around its own optical axis during installation.

6. The lidar according to claim 1, wherein, The light-emitting angle of the transmitting device is set such that the light spots formed by the emitted light corresponding to the multiple optical channels are parallel to each other.

7. The lidar according to claim 6, wherein, The incident angle of the reflected light emitted from the first optical channel incident on the scanning device is a first incident angle, and the incident angle of the reflected light emitted from the second optical channel incident on the scanning device is a second incident angle, and the first incident angle is greater than the second incident angle; The rotation angle of the transmitting device in the first optical channel around its own optical axis during installation is greater than the rotation angle of the transmitting device in the second optical channel around its own optical axis during installation.

8. The lidar according to any one of claims 1 to 7, characterized in that, The transmitting device includes an edge-emitting laser.

9. The lidar according to any one of claims 1 to 7, characterized in that, The optical channel further includes: a beam splitter for transmitting the transmitted light provided by the transmitting device and also for reflecting an echo beam, or for reflecting the transmitted light provided by the transmitting device and also for transmitting an echo beam.

10. The lidar according to any one of claims 1 to 7, characterized in that, The optical channel further includes: a lens for converging the transmitted light to the reflecting device.

11. A lidar, characterized in that, Comprising: Multiple optical channels, including a first optical channel and a second optical channel; Each of the first optical channel and the second optical channel includes: A transmitting device for providing transmitted light, A reflecting device including a mirror for reflecting the transmitted light to form reflected light; A Dove prism located on the optical path between the transmitting device and the reflecting device; A scanning device for scanning and emitting the reflected light corresponding to the multiple optical channels to form emitted light for detecting a target; Wherein, the mirrors in the multiple optical channels are independent of each other; in the first optical channel, the reflected light is incident on the scanning device at a first incident angle, and in the second optical channel, the reflected light is incident on the scanning device at a second incident angle, and the first incident angle is greater than the second incident angle; The Dove prism is arranged to make the spots formed by the emitted light corresponding to the multiple optical channels parallel to each other.

12. The lidar according to claim 11, wherein, The rotation angle set by the Dove prism in the first optical channel around its own optical axis during installation is greater than the rotation angle set by the Dove prism in the second optical channel around its own optical axis during installation.

Images