Laser radar optical system and laser radar

Abstract

The present invention discloses a laser radar optical system and a laser radar, and relates to the technical field of measuring instruments. The laser radar optical system includes a transmitting system and a receiving system, wherein the transmitting system includes a laser light source, a corrective lens group and a collimating lens group in sequence along the light transmission direction, the laser light source is used to emit multiple light beams, the corrective lens group includes at least one corrective lens, and the corrective lens is used to correct the multiple light beams emitted by the laser light source so that the central axis of each of the light beams is aligned with the entrance pupil center of the collimating lens group. The present invention aims to provide a simple and effective laser radar optical system to improve the vertical spatial resolution of the laser radar.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring instruments, and in particular to a laser radar optical system and a laser radar. Background Art

[0002] At present, mechanical lidar is one of the most effective ways to achieve the stability of autonomous driving. It uses multiple lasers and photodetectors to achieve multi-path signal detection. Multiple lasers are arranged vertically at different heights on the focal plane of the transmitting lens according to predetermined pointing angles to achieve a preset vertical field of view.

[0003] To improve the vertical spatial resolution of LiDAR, the methods that are currently being used are: (1) reducing the spacing of lasers on a single transmitting board. However, when multiple lasers are integrated on a transmitting board, there needs to be a preset pointing angle between the lasers, which can easily cause interference during the manufacturing process, increasing the difficulty of processing and limiting the lower limit of the laser spacing, which in turn limits the vertical spatial resolution of LiDAR. (2) placing multiple transmitting boards side by side and staggering them in height, and reducing the laser spacing by staggering the laser height. This will make installation and debugging within a given space more difficult, and the system space is difficult to compress. With current technology, it is difficult to find a simplified way to improve the vertical spatial resolution of LiDAR. Summary of the invention

[0004] The main purpose of the present invention is to propose a laser radar optical system and a laser radar, aiming to provide a simple and effective laser radar optical system to improve the vertical spatial resolution of the laser radar.

[0005] To achieve the above-mentioned purpose, the present invention provides a laser radar optical system, which includes a transmitting system and a receiving system, wherein the transmitting system includes a laser light source, a corrective lens group and a collimating lens group in sequence along the light transmission direction, the laser light source is used to emit multiple light beams, the corrective lens group includes at least one corrective lens, and the corrective lens is used to correct the multiple light beams emitted by the laser light source so that the central axis of each of the light beams is aligned with the entrance pupil center of the collimating lens group.

[0006] Optionally, the corrective lens assembly comprises one corrective lens; and / or,

[0007] The corrective lens has positive optical power, and the corrective lens has a first surface disposed toward the laser light source and a second surface disposed away from the laser light source, wherein the first surface is a plane and the second surface is a convex surface.

[0008] Optionally, the corrective lens is a cut-edge lens.

[0009] Optionally, the laser light source includes at least one laser emitting plate, each of the laser emitting plate includes multiple lasers, the multiple lasers are arranged at intervals along the height direction of the laser emitting plate, the central axes of the light beams emitted by each laser are parallel to each other, and the central axes are parallel to the optical axis of the corrective lens group.

[0010] Optionally, the laser emitting plate further comprises at least one shaping microlens, and the shaping microlens is arranged on the light output side of the multiple lasers and is used to compress the fast-axis divergence angle of the lasers.

[0011] Optionally, the distance between the correction lens and the shaping microlens is D, 0.5mm≤D≤5mm; and / or,

[0012] The shaping microlens is a bare optical fiber, and the central axis of the bare optical fiber is arranged perpendicular to the light beam emitted by the laser.

[0013] Optionally, the surface of the bare optical fiber is coated with an anti-reflection film, and the anti-reflection film corresponds to the wavelength band of the light beam emitted by the laser.

[0014] Optionally, the receiving system includes a receiving lens group and at least one laser receiving plate in sequence along the light transmission direction;

[0015] The laser radar optical system also includes a transmitting reflector group and a receiving reflector group. The transmitting reflector group is arranged between the correcting mirror group and the collimating mirror group, and the receiving reflector group is arranged between the receiving lens group and the laser receiving plate.

[0016] Optionally, the emitting reflector group includes at least one emitting reflector; and / or,

[0017] The receiving reflector group includes at least one receiving reflector.

[0018] In addition, the present invention also proposes a laser radar, which includes the laser radar optical system as described above.

[0019] The laser radar optical system proposed in the present invention includes a transmitting system and a receiving system, wherein the transmitting system includes a laser light source, a corrective lens group and a collimating lens group in sequence along the light transmission direction. The corrective lens group is used to correct multiple light beams emitted by the laser light source, so that each light beam enters the collimating lens group in a manner in which the central axis is aligned with the entrance pupil center of the collimating lens group, so that the light beam emitted by the laser light source does not need to have a preset pointing angle, thereby avoiding mutual interference between the light beams, allowing the laser interval to be smaller, which is beneficial to improving the vertical spatial resolution of the laser radar. In addition, the optical system has a simple structure, low manufacturing difficulty, and is conducive to quantitative production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of a first embodiment of a laser radar optical system proposed by the present invention;

[0021] Figure 2 for Figure 1 Schematic diagram of the launch system;

[0022] Figure 3 for Figure 1 Front view of a medium corrective lens;

[0023] Figure 4 for Figure 3 a top view of the corrective lens shown;

[0024] Figure 5 A structural diagram of an embodiment of a laser emitting plate in a laser radar optical system proposed by the present invention;

[0025] Figure 6 A structural diagram of another embodiment of a laser emitting plate in a laser radar optical system proposed by the present invention;

[0026] Figure 7 A schematic diagram of a second embodiment of the laser radar optical system provided by the present invention;

[0027] Figure 8 This is a schematic diagram of a third embodiment of the laser radar optical system proposed in the present invention.

[0028] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings.

[0029] Description of Figure Numbers:

[0030]

[0031] DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0034] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0035] The vertical spatial resolution of LiDAR is determined by the vertical spacing of the lasers at the transmitting end. To improve the vertical spatial resolution of LiDAR, the methods that are currently used are mainly: (1) reducing the spacing of lasers on a single transmitting board. However, when multiple lasers are integrated on a transmitting board, there needs to be a preset pointing angle between the lasers, which is easy to cause interference during the manufacturing process, thereby increasing the difficulty of processing, limiting the lower limit of the laser spacing, and further limiting the vertical spatial resolution of LiDAR; (2) placing multiple transmitting boards side by side and staggered in height, and reducing the laser spacing by staggering the laser height. This will make it more difficult to install and debug within a given space, and the system space is also difficult to compress. As far as current technology is concerned, it is difficult to find a simplified way to improve the vertical spatial resolution of LiDAR.

[0036] In view of this, the present invention proposes a laser radar optical system 100, which includes a transmitting system 10 and a receiving system 20, wherein the transmitting system 10 includes a laser light source 1, a corrective lens group and a collimating lens group 3 in sequence along the light transmission direction. Figures 1 to 4 This is an embodiment of the laser radar optical system 100 proposed by the present invention.

[0037] Reference Figure 1 and Figure 2The laser radar optical system 100 includes a transmitting system 10 and a receiving system 20. The transmitting system 10 includes a laser light source 1, a correction lens group, and a collimator lens group 3 arranged in sequence along the light transmission direction. The laser light source 1 is used to emit multiple light beams. The correction lens group includes at least one correction lens 2, which is used to correct the multiple light beams emitted by the laser light source 1 so that each light beam enters the collimator lens group 3 in a manner such that the central axis of the light beam is aligned with the entrance pupil center of the collimator lens group 3. On the one hand, the correction lens 2 of this embodiment pre-corrects the light beam, so that the light beam emitted by the laser light source 1 no longer needs a preset pointing angle, thereby relaxing the restrictions on the laser light beam. If each light beam is emitted in a manner where the central axis is parallel to each other, it can not only avoid mutual interference between the light beams, so that the interval between the lasers 110 can be reduced, but also reduce the processing difficulty, which is conducive to improving the vertical spatial resolution of the laser radar. On the other hand, since the light beams corrected by the correction lens group are all incident on the entrance pupil center of the collimating lens group 3 with the central axis, the energy of each light beam can be fully utilized, so there is no need to increase the optical aperture of the system, thereby reducing the cost and space occupied by the collimating lens group 3. The collimating lens group 3 is composed of one or more optical lenses, and the lens preferably adopts a Gaussian structure, which is used to effectively collimate the light beam corrected by the correction lens group to form multiple parallel light beams with different field of view angles, thereby realizing the vertical field of view coverage of the laser radar.

[0038] Among them, Figure 1 As shown, the receiving system 20 includes a receiving lens group 8 and a laser receiving plate 6 which are sequentially arranged along the light transmission direction. The receiving lens group 8 is composed of one or more optical lenses, and the lens preferably adopts a Gaussian structure, which is used to converge the light beam reflected by the detection object on the laser receiving plate 6. The material of the receiving lens group 8 can be optical plastic; the laser receiving plate 6 includes a plurality of photodetectors for processing the received light beam. Further, in order to reduce the adverse effects caused by the interference light beam, the receiving system 20 can also include a filter 7, which is arranged between the receiving lens group 8 and the laser receiving plate 6, and is used to filter each received light beam to filter out the light beam whose wavelength is not within the preset wavelength range, so as to prevent these interference light beams from affecting the light beam within the wavelength range. Moreover, since the filter 7 is arranged on the light incident side of the laser receiving plate 6, it can also play a role in sealing and protecting the laser receiving plate 6.

[0039] After being corrected by the correcting lens group, the light beam emitted by the laser light source 1 enters the collimating lens group 3 with its central axis aligned with the entrance pupil center of the collimating lens group 3. The collimated light beam is reflected by the detection object in front, and at least part of the reflected light beam enters the receiving lens group 8 and then converges on the laser receiving plate 6.

[0040] In a specific implementation, the transmitting system 10 and the receiving system 20 may be as follows: Figure 1As shown, they are arranged symmetrically along the system axis 5, and a light isolation device is provided between the two to achieve spatial separation, thereby avoiding mutual interference. Moreover, the collimating lens group 3 and the receiving lens group 8 of this embodiment can use the same components, which is conducive to reducing costs during mass production.

[0041] The corrective lens assembly includes at least one corrective lens 2. Specifically, when the corrective lens assembly includes a plurality of corrective lenses 2, the plurality of corrective lenses 2 are coaxially arranged. Figure 1 As shown, the corrective lens assembly includes a corrective lens 2, so that it can ensure that most of the light beam can enter the collimating lens assembly 3 in a manner that the central axis of the light beam is aligned with the entrance pupil center of the collimating lens assembly 3, thereby reducing production costs while ensuring product quality.

[0042] See also Figure 3 and Figure 4 The corrective lens 2 has positive optical power, and the corrective lens 2 has a first surface 21 disposed toward the laser light source 1 and a second surface 22 disposed away from the laser light source 1, wherein the first surface 21 is a plane and the second surface 22 is a convex surface.

[0043] In order to install the corrective lens 2, the transmitting system 10 of this embodiment may also include a bracket for installing the laser light source 1 and the corrective lens group. Since the corrective lens group is arranged on the light-emitting side of the laser light source 1 and is arranged close to the laser light source 1, the corrective lens group can effectively protect the laser light source 1, avoid damage to the laser light source 1 during the installation and debugging process, and avoid impurities from being deposited on the surface of the laser light source 1. Furthermore, the bracket can also be set as a cylindrical structure with openings at both ends, the laser light source 1 is installed at the first end of the bracket, and the corrective lens group is installed at the second end of the bracket. In this way, the bracket, the laser light source 1 and the corrective lens group can enclose a closed space to prevent impurities from entering the closed space, thereby effectively increasing the device life and system life. Among them, the corrective lens 2 can be fixedly installed on the bracket by gluing.

[0044] In this embodiment, the corrective lens 2 is preferably a cut-edge lens. Based on a conventional circular lens, such as Figure 3 As shown, the symmetrically distributed areas A and B are cut off to form a trimmed lens. Compared with a conventional circular lens, the trimmed lens is smaller in size and more suitable for assembly. Not only is the required bracket easier to process, but also when installed on the bracket, the assembly is more convenient and occupies less space, which can make the optical system more compact. Figure 3 and Figure 4 As shown, the present embodiment preferably adopts a rectangular cut-edge lens, that is, a cut-edge lens obtained by cutting out regions A, B, C and D on the basis of a conventional circular lens, which further reduces the volume of the lens and enables the lens to form four straight sides, further reducing the difficulty of assembly.

[0045] The laser light source 1 of this embodiment includes at least one laser emitting board 11, and each laser emitting board 11 is arranged on the same vertical plane. Each laser emitting board 11 includes a plurality of lasers 110, and the plurality of lasers 110 are arranged at intervals along the height direction of the laser emitting board 11. The central axes of the light beams emitted by the lasers 110 are parallel to each other, and the central axes are parallel to the optical axis of the correction lens group. Figure 2 For example, the laser light source 1 of this embodiment includes a laser emitting plate 11, and the laser emitting plate 11 includes nine lasers 110 spaced apart from top to bottom. The central axes of the light beams emitted by the nine lasers 110 and the optical axis of the corrective lens 2 remain parallel to each other. That is to say, there is no interference angle between the light beams emitted by the nine lasers 110, which reduces the difficulty of manufacturing the laser emitting plate 11.

[0046] To optimize system performance, the laser emitting board 11 of this embodiment further includes at least one shaping microlens 120, which is disposed on the light-emitting side of the plurality of lasers 110 and is used to compress the fast-axis divergence angle of the lasers 110. Figure 5 and 6 , the right side of the laser 110 is the light-emitting side of the laser 110, and the shaping microlens 120 is arranged on the light-emitting side of the laser 110, so that the light beam emitted by the laser 110 is shaped by the shaping microlens 120 before being emitted. Since the light beams emitted by the multiple lasers 110 on the laser emitting board 11 of this embodiment are all emitted in a manner in which the central axes are parallel to each other, at least part of the light beams can be shaped at the same time, that is, one or more shaping microlenses 120 can be arranged on the light-emitting sides of the multiple lasers 110, as shown in FIG. Figure 5 As shown, a shaping microlens 120 is correspondingly arranged on the light-emitting side of each laser 110, or two or more adjacent lasers 110 may share a shaping microlens 120, or Figure 6 As shown, all lasers 110 share one shaping microlens 120 , which further simplifies the manufacturing process of the laser emitting plate 11 .

[0047] When the bare optical fiber is arranged on the light-emitting side of the laser 110 in a manner such that the central axis is perpendicular to the light beam emitted by the laser 110, the light beam emitted by the laser 110 can also achieve the effect of shaping the light beam after passing through the bare optical fiber. In this embodiment, the shaping microlens 120 is preferably a bare optical fiber, and Figure 5 and Figure 6 As shown, the central axis of the bare optical fiber is arranged perpendicular to the light beam emitted by the laser 110 .

[0048] Furthermore, in this embodiment, the surface of the bare optical fiber is coated with an anti-reflection film, and the anti-reflection film corresponds to the wavelength band of the light beam emitted by the laser 110, thereby reducing the reflected light formed on the surface of the bare optical fiber and increasing the light transmittance.

[0049] The light emitting position of the shaping microlens 120 forms a light emitting plane, and the distance between the light emitting plane and the first surface 21 of the correcting lens 2 is D. In this embodiment, the value range of D is preferably: 0.5mm≤D≤5mm. Within this range, the correction effect of the correcting lens 2 on the light beam can be ensured, and the smaller D is, the more compact the system is.

[0050] In order to further improve the compactness of the optical system, the laser radar optical system 100 of the present invention also includes a transmitting reflector group and a receiving reflector group, wherein the transmitting reflector group is arranged between the correcting lens group and the collimating lens group 3, and is used to fold the light transmitted from the correcting lens group to the collimating lens group 3, thereby shortening the distance between the laser light source 1 and the collimating lens group 3 by changing the optical path to make the transmitting system 10 compact, and adjusting the shape of the transmitting system 10 to adapt to different external structures by changing the optical path; the receiving reflector group is arranged between the receiving lens group 8 and the laser receiving plate 6, and is used to fold the light transmitted from the receiving lens group 8 to the laser receiving plate 6, thereby shortening the distance between the receiving lens group 8 and the laser receiving plate 6 by changing the optical path to make the receiving system 20 compact, or adjusting the shape of the transmitting system 10 to adapt to different external structures.

[0051] In a specific implementation, the emitting reflector group includes at least one emitting reflector, which can be a plane reflector or a curved reflector; similarly, the receiving reflector group includes at least one receiving reflector, which can be a plane reflector or a curved reflector.

[0052] exist Figure 7 In the second embodiment of the laser radar optical system 100 shown, the laser radar optical system 100 includes a transmitting system 10 and a receiving system 20. The transmitting system 10 includes a laser light source 1, a correction lens 2, a first reflector 41 and a collimating lens group 3 in sequence along the light transmission direction, and the first reflector 41 is a plane reflector; the receiving system 20 includes a receiving lens group 8, a third reflector 91, a narrow band filter 7 and a laser receiving plate 6 in sequence along the light transmission direction, and the third reflector 91 is a plane reflector. After the first reflector 41 and the third reflector 91 respectively fold the light path, the laser radar optical system 100 of this embodiment has a compact structure and occupies a small space.

[0053] exist Figure 8In the third embodiment of the laser radar optical system 100 shown, the laser radar optical system 100 includes a transmitting system 10 and a receiving system 20. The transmitting system 10 includes a laser light source 1, a corrective lens 2, a first reflector 41, a second reflector 42 and a collimating lens group 3 in sequence along the light transmission direction, and the first reflector 41 and the second reflector 42 are both plane reflectors; the receiving system 20 includes a receiving lens group 8, a fourth reflector 92, a third reflector 91, a narrow-band filter 7 and a laser receiving plate 6 in sequence along the light transmission direction, and the fourth reflector 92 and the third reflector 91 are plane reflectors.

[0054] Based on the structure of the laser radar optical system 100, the present invention further proposes a laser radar. The laser radar includes the laser radar optical system 100 as described above. Since the laser radar adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0055] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A laser radar optical system, characterized in that: The laser radar optical system includes a transmitting system and a receiving system, wherein the transmitting system includes a laser light source, a corrective lens group and a collimating lens group in sequence along the light transmission direction, the laser light source is used to emit multiple light beams, the corrective lens group includes at least one corrective lens, and the corrective lens is used to correct the multiple light beams emitted by the laser light source so that the central axis of each of the light beams is aligned with the entrance pupil center of the collimating lens group; The corrective lens assembly includes a corrective lens; The corrective lens has positive optical power, and the corrective lens has a first surface disposed toward the laser light source and a second surface disposed away from the laser light source, wherein the first surface is a plane and the second surface is a convex surface; The laser light source includes at least one laser emitting board, each of which includes a plurality of lasers, which are arranged at intervals along the height direction of the laser emitting board, and the central axes of the light beams emitted by the lasers are parallel to each other, and the central axes are parallel to the optical axis of the corrective lens assembly; The laser emitting plate further comprises at least one shaping microlens, which is arranged on the light-emitting side of the plurality of lasers and is used to compress the fast-axis divergence angle of the lasers; The shaping microlens is a bare optical fiber, and the central axis of the bare optical fiber is arranged perpendicular to the light beam emitted by the laser.

2. The laser radar optical system according to claim 1, characterized in that: The corrective lens is a cut-edge lens.

3. The laser radar optical system according to claim 1, characterized in that: The distance between the correction lens and the shaping microlens is D, 0.5mm≤D≤5mm.

4. The laser radar optical system according to claim 1, characterized in that: The surface of the bare optical fiber is coated with an anti-reflection film, and the anti-reflection film corresponds to the wavelength band of the light beam emitted by the laser.

5. The laser radar optical system according to claim 1, characterized in that: The receiving system includes a receiving lens group and at least one laser receiving plate in sequence along the light transmission direction; The laser radar optical system also includes a transmitting reflector group and a receiving reflector group. The transmitting reflector group is arranged between the correcting mirror group and the collimating mirror group, and the receiving reflector group is arranged between the receiving lens group and the laser receiving plate.

6. The laser radar optical system according to claim 1, characterized in that: The emitting reflector group includes at least one emitting reflector; and / or, The receiving reflector group includes at least one receiving reflector.

7. A laser radar, characterized in that: The laser radar comprises a laser radar optical system as described in any one of claims 1 to 6.

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