Diffusion unit, emission system, lidar and vehicle

Abstract

The present application relates to the technical field of laser radar, and specifically provides a diffusion unit, a transmitting system, a laser radar and a vehicle, aiming to solve the problem that the existing diffusion unit is difficult to convert a single laser beam into a surface array laser beam. To this end, the diffusion unit of the present application comprises a lens, the lens comprising an incident surface and an exit surface opposite to each other, the base surface of the exit surface being a curved surface, the exit surface comprising a plurality of exit planes, the exit planes being planes, and the included angle between any two exit planes being greater than 0° and less than 180°. A single beam of light enters the incident surface of the lens and exits from the plurality of exit planes on the exit surface, the light exiting from each exit plane converges into a laser beam, and the plurality of laser beams exiting from the plurality of exit planes of one lens diffuse to form a surface array light.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser radar, and particularly provides a diffusion unit, a transmitting system, a laser radar and a vehicle. BACKGROUND

[0002] The laser radar is a key component for realizing automatic driving. The laser radar can map objects around the vehicle body to form a high-precision 3D map, and the vehicle can automatically drive according to the map formed by the laser radar mapping. The laser radar includes a transmitting system and a receiving system. The transmitting system can emit a planar laser array to a specified direction. The laser is reflected by an obstacle and is received by the receiving system. By measuring the propagation distance between the transmitting system and the target object, analyzing the reflection energy, amplitude, frequency and phase of the reflected wave on the surface of the object, and the like, the accurate three-dimensional structure information of the target object can be presented.

[0003] The laser radar is divided into three types according to the transmitting system, namely, a mechanical laser radar, a semi-solid laser radar and a solid laser radar. The mechanical laser radar can realize 360° scanning, and the semi-solid laser radar and the solid laser radar can realize scanning within a certain angle. The greater the scanning angle of the semi-solid laser radar and the solid laser radar, the greater the imaging range. Therefore, the diffusion unit is included in the transmitting system of the semi-solid laser radar and the solid laser radar. The diffusion unit can expand the emission angle of the laser to improve the scanning angle.

[0004] Taking the semi-solid laser radar as an example, the transmitting system of the semi-solid laser radar includes a plurality of laser emitters, a MEMS (Micro-Electro-Mechanical System) micro-mirror and a diffusion unit. The MEMS can drive the micro-mirror to swing at a high speed. Each laser emitter corresponds to one MEMS micro-mirror. After each laser beam is irradiated to the micro-mirror, the linear array laser is formed through the reflection of the micro-mirror. The linear array laser can expand the divergence angle of the linear array laser after passing through the diffusion unit. The linear array laser array generated by the laser emitter, the MEMS micro-mirror and the diffusion unit can form a planar laser array.

[0005] The commonly used diffusion unit currently includes one or more lens groups. Each lens group includes a convex lens and a concave lens arranged in sequence along the laser emission direction. The side of the concave lens facing the convex lens is a concave surface, and the side of the concave lens away from the convex lens is a flat surface. The laser irradiated to the convex lens is converted into parallel light after passing through the convex lens, and is converted into diffused light after passing through the concave lens, so as to be diffused outward with a larger wide angle. The diffusion unit has the disadvantage that it is difficult to directly convert a single laser beam into a planar laser array.

[0006] Therefore, there is an urgent need for a diffusion unit, a transmitting system, a laser radar and a vehicle to solve the problem that the existing diffusion unit is difficult to convert a single laser beam into a planar array laser beam. SUMMARY

[0007] The present application aims to solve the above technical problems, i.e., to solve the problem that the existing diffusion unit is difficult to convert a single laser beam into a planar array laser beam.

[0008] In a first aspect, the present application provides a diffusion unit, which comprises a lens, the lens comprising an incident surface and an exit surface, the base surface of the exit surface being a curved surface, the exit surface comprising a plurality of exit planes arranged based on the base surface, the included angle between any two exit planes being greater than 0° and less than 180°; when a light beam is incident from the incident surface, the light beam is refracted by the lens to be emitted from the exit planes to form a diffused planar array light.

[0009] In the specific embodiments of the diffusion unit, the incident surface is a plane, and the base surface is a convex surface; or, the incident surface and the base surface are both convex surfaces.

[0010] In the specific embodiments of the diffusion unit, the incident surface is a plane, and the base surface is a concave surface; or, the incident surface and the base surface are both concave surfaces.

[0011] In the specific embodiments of the diffusion unit, the areas of all the exit planes are the same; and / or, the spacings between any two adjacent exit planes are the same.

[0012] In the specific embodiments of the diffusion unit, the base line of the exit surface on the central cross section is one branch of a hyperbola, the base surface is obtained by rotating the base line around the principal optical axis, and any one exit plane is parallel to the circumscribed plane corresponding to the base surface.

[0013] In the specific embodiments of the diffusion unit, the edges of the exit planes are provided with light shielding members.

[0014] In the specific embodiments of the diffusion unit, the diffusion unit comprises a first lens and a plurality of second lenses, the first lens and the second lenses are the same in structure, and the plurality of exit planes of the first lens are arranged one by one corresponding to the plurality of second lenses; when a light beam is incident from the incident surface of the first lens, the light refracted and emitted from the exit planes of the first lens can be incident into the second lenses, and then be refracted and emitted by the second lenses.

[0015] In a second aspect, the present application provides a transmitting system, which comprises the above-mentioned diffusion unit and a laser transmitter, the laser transmitter being capable of emitting parallel laser beams, and the laser beams being converted into diffused light after being incident into the lens from the incident surface.

[0016] In the specific embodiments of the transmitting system, the transmitting system further comprises a rotator, and the laser transmitter and the diffusion unit are both mounted on the rotator.

[0017] In a third aspect, the present application provides a laser radar comprising the above-mentioned transmitting system.

[0018] In a fourth aspect, the present application provides a vehicle comprising the above-mentioned laser radar.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] The diffusion unit provided by the present application comprises a lens, the lens comprises an incident surface and an exit surface, the base surface of the exit surface is a curved surface, the exit surface comprises a plurality of exit planes arranged based on the base surface, and the included angle between any two exit planes is greater than 0° and less than 180°; a single beam of light is incident from the incident surface of the lens and is emitted from the plurality of exit planes on the exit surface, the light emitted from each exit plane converges to form a beam of light, and the plurality of beams of light emitted from the plurality of exit planes of one lens are diffused to form a planar array of light.

[0021] Furthermore, the edge of the exit plane is provided with a light shielding piece, the light shielding piece can shield the edge of the exit plane, avoid disorderly scattering of laser light at the edge of the exit plane, and improve the accuracy of the surveying result of the laser radar.

[0022] Furthermore, the diffusion unit comprises a first lens and a plurality of second lenses, the plurality of exit planes of the first lens are arranged one by one corresponding to the plurality of second lenses; when a beam of light is incident from the incident surface of the first lens, the light refracted out of the exit plane of the first lens can be incident into the second lens, and then be refracted and emitted out of the second lens. When the beam of light is incident on the incident surface of the first lens, the beam of light is diffused after passing through the first lens and is emitted out of the exit surface of the first lens as a plurality of primary beams of light, each primary beam of light is incident on the incident surface of one second lens, and the primary beam of light is diffused after passing through the second lens and is emitted out of the exit surface of the second lens as a plurality of secondary beams of light, the plurality of secondary beams of light emitted out of each second lens after diffusion can form a planar array of light, and the planar arrays of light formed after diffusion by the plurality of second lenses can be combined to form a planar array of light with a larger area, so as to improve the diffusion range of the beam of light. BRIEF DESCRIPTION OF DRAWINGS

[0023] The preferred embodiments of the present application will be described below with reference to the accompanying drawings, in which:

[0024] Figure 1 is a front view of the lens provided by the first embodiment of the present application;

[0025] Figure 2 is a left view of the lens provided by the second embodiment of the present application

[0026] Figure 3 is a cross-sectional view of A-A in Figure 2 ​

[0027] Figure 4 is Figure 3 an enlarged view of the local part B in FIG. 1;

[0028] Figure 5 is Figure 2 an enlarged view of the local part C in FIG. 1;

[0029] Figure 6 is a schematic diagram of a plane array laser formed after diffusion of a lens according to an embodiment of the present application;

[0030] Figure 7 is a light path diagram of a laser formed after diffusion of a lens according to an embodiment of the present application;

[0031] Figure 8 is a light path diagram of a laser formed after diffusion of a lens according to another embodiment of the present application;

[0032] Figure 9 is a front view of a lens according to an embodiment of the present application.

[0033] Explanation of Reference Signs:

[0034] 1, lens; 11, incident surface; 12, exit surface; 121, exit plane; 13, main optical axis; 2, light shielding member; 14, first lens; 15, second lens. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. It should be understood by those skilled in the art that the embodiments are merely used to explain the technical principles of the present application, and are not intended to limit the scope of protection of the present application.

[0036] It should be noted that, in the description of the present application, the terms indicating the direction or position relationship such as "upper", "lower", "left", "right", "inner", "outer" and the like are based on the direction or position relationship shown in the drawings, which is merely for the convenience of description, and does not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0037] In addition, it should be further noted that, in the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "setting", "connecting" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. Those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific circumstances.

[0038] Embodiment one

[0039] To solve the problem that the existing diffusion unit is difficult to convert a single laser beam into a planar array of laser beams, an embodiment of the present application provides a vehicle. The vehicle is provided with a laser radar, which can map objects around the vehicle to form a high-precision 3D map, and the vehicle performs autonomous driving according to the map formed by the laser radar mapping. The laser radar includes a transmitting system and a receiving system. The transmitting system can emit a planar array of laser beams in a specified direction. When the laser beams encounter an obstacle, they will be reflected and received by the receiving system. After receiving the reflected laser beams, the receiving system calculates the propagation distance between the transmitting system and the target object by the time of flight of the laser beams, and the receiving system can also present the accurate three-dimensional structure information of the target object by detecting the energy size and the amplitude, frequency and phase of the reflected laser beams. The transmitting system includes at least a laser emitter and a diffusion unit. The laser emitter emits parallel laser beams. The laser beams directly or indirectly after reflection or indirectly after refraction enter the diffusion unit. After passing through the diffusion unit, the laser beams increase the range of emission.

[0040] As shown in Figure 1 and Figure 2 , the diffusion unit includes a lens 1. The refractive index of the lens 1 is greater than the refractive index of the medium around the lens 1, and the lens 1 can convert the incident parallel light into diffuse light. Generally, the lens 1 is located in the air, and the refractive index of the lens 1 is greater than 1. The specific way in which the lens 1 converts the incident parallel light into diffuse light is that the lens 1 converts the incident parallel light into convergent light, and the convergent light converges and then diffuses into diffuse light.

[0041] The lens 1 includes opposite incident surface 11 and exit surface 12. The exit surface 12 has a base surface, and the exit surface 12 is machined based on the base surface. The base surface is a convex curved surface, and the incident surface 11 is a plane. The laser light enters from the incident surface 11 and exits from the exit surface 12. If the laser light is vertically incident from the incident surface 11, the direction of the laser light does not change after entering the lens 1, and the laser light is still parallel light.

[0042] Regarding the shapes of the incident surface 11 and the exit surface 12, it should be noted that although the incident surface 11 is a plane and the base surface of the exit surface 12 is a convex curved surface in this embodiment, this is not a limitation of the present application. Within the principle of the present application, those skilled in the art can also set the incident surface 11 as a convex surface and the base surface of the exit surface 12 as a convex surface in other embodiments, so as to convert the parallel light incident into the incident surface 11 into convergent light emitted from the exit surface 12, and the convergent light converges and then diffuses into diffuse light.

[0043] The exit surface 12 comprises a plurality of exit planes 121, which are machined by removing material on the base surface of the exit surface 12, and the included angle between any two exit planes 121 is greater than 0° and less than 180°. In the process of the laser emitted from the exit surface 12, the laser emitted from the same exit plane 121 has approximately the same emission direction, and a single beam of laser can be formed. The single beam of laser emitted from each exit plane 121 converges and then diverges to form a planar array of laser. Each exit plane 121 is an independent light emitting point. The purpose of setting the exit plane 121 is to concentrate part of the laser to form a single parallel laser, so as to avoid too much dispersion of the laser and too weak energy. If the laser energy is not strong enough, the emitted laser is difficult to be recognized and analyzed by the receiving system of the laser radar after reflection. The purpose of setting the included angle between any two exit planes 121 to be greater than 0° and less than 180° is that the emission direction of the single beam of laser emitted from each exit plane 121 is different, so as to avoid that any two beams of laser fall on the same scanning target point. If any two beams of laser fall on the same scanning point, the energy of the laser falling on the scanning point is enhanced, and the energy of the laser reflected from the scanning point is also enhanced accordingly, which will interfere with the analysis result of the laser radar.

[0044] It is worth noting that, as shown in Figure 3 , the lens 1 is a plano-convex lens, and when the laser is vertically incident from the incident surface 11, the emission direction of the laser entering the lens 1 does not change, and the laser emitted toward each exit plane 121 is parallel light. The direction of the laser emitted from each exit plane 121 is exactly the same, which is a parallel light beam.

[0045] The areas of all the exit planes 121 are the same, and the energy of the laser emitted from each exit plane 121 is approximately the same, so that the energy of the laser beam emitted from each exit plane 121 is also approximately the same. The closer the energy of each beam of laser in the planar array of laser, the closer the energy of the reflected laser when the laser meets the same obstacle, and the result obtained by the receiving system after receiving and analyzing the reflected laser is also more accurate. Of course, in other embodiments, other ways can also be used to make the energy of the laser beam emitted from each exit plane 121 approximately the same, and the present application does not make specific limitations thereon, which should be included in the protection scope of the present application.

[0046] The base line of the center section of the exit surface 12 is designed as a branch of a hyperbola, and the exit surface 12 is a curved surface obtained by rotating the base line around the main optical axis 13. The center section is perpendicular to the entrance surface 11, the main optical axis 13 is perpendicular to the entrance surface 11 and passes through the center point of the entrance surface 11, and the main optical axis 13 is located in the center section. Each exit plane 121 is parallel to an outer tangent plane different from the base plane. The laser is vertically incident from the entrance surface 11, and the laser beams emitted from each exit plane 121 can converge at the focal point of the plano-convex lens and then diverge, so that the distribution of each laser beam in the planar array laser is more orderly. Without departing from the principles of the present application, in other embodiments, those skilled in the art can also set the exit surface 12 to other types of convex surfaces, as long as the laser beams emitted from each exit plane 121 can first converge and then diverge to obtain an orderly planar array laser.

[0047] In combination Figure 4 As shown, the distance between adjacent exit planes 121 is m, the distance between adjacent exit planes 121 is the distance between the center points of two adjacent exit planes 121, and is also the distance between one side of an exit plane 121 and the corresponding side of an adjacent exit plane 121. The distance between any two adjacent exit planes 121 is the same, and the distance between the laser beams emitted from any two adjacent exit planes 121 after divergence is equal, so as to improve the uniformity of the distribution of each laser beam in the planar array laser.

[0048] Let β be the base plane of the exit surface 12, the refractive index of the lens 1 be K, the incident angle of the laser towards the exit plane 121 be θ, and the exit angle be α, then sinα / sinθ=K.

[0049] In addition, as Figure 5 shown, at the edge of the exit plane 121, especially at the junction between two adjacent exit planes 121, a light shielding piece 2 is arranged. The junction between two adjacent exit planes 121 is an optical transient line, and due to the influence of machining precision, there may be defects such as damage at the junction. The laser irradiated to the junction will be scattered disorderly. The laser scattered disorderly interferes with each other, which may be strengthened at non-scanning points to generate interference points, affecting the mapping result of the laser radar. The laser scattered disorderly may also be superimposed with the laser beam emitted from the exit plane 121 at a certain point, changing the energy of the laser reflected from the point, thereby affecting the mapping result of the laser radar. The light shielding piece 2 can shield the edge of the exit plane 121, avoid the laser from being scattered disorderly at the edge of the exit plane 121, especially at the junction between two adjacent exit planes 121, so as to improve the accuracy of the mapping result of the laser radar.

[0050] As Figure 6 shown, the spot distance of the laser projected on the plane after passing through the lens is n. In combination with Figure 7As shown, the focal length of the lens 1 is D, and the laser emitted from the exit surface 12 is projected on a plane perpendicular to the main optical axis 13 and at a distance S from the focal point of the lens 1, then n = mS / D. The smaller the projected spot spacing n, the higher the scanning accuracy of the laser radar. By reducing the spacing m between two adjacent exit planes 121 or increasing the focal length D, the projected spot spacing n can be improved to improve the scanning accuracy of the radar. Reducing the spacing m between two adjacent exit planes 121 requires improving the manufacturing process. Increasing the focal length D will reduce the projection range of the laser after passing through the diffusion unit, that is, the viewing angle of the laser radar is reduced, at which time the viewing angle of the laser radar can be increased by increasing the number of diffusion units and laser emitters.

[0051] In other embodiments, as Figure 8 As shown, the diffusion unit includes a first lens 14 and a plurality of second lenses 15, the first lens 14 and the second lens 15 are both the same structure as the lens 1 described above, the plurality of exit planes 121 of the first lens 14 are arranged one by one corresponding to the plurality of second lenses 15, and the entrance surface 11 of the second lens 15 faces the exit surface 12 of the first lens 14. The laser emitted by the laser emitter is directed to the entrance surface 11 of the first lens 14, and after being diffused by the first lens 14, a plurality of primary lasers are emitted from the exit surface 12 of the first lens 14, each primary laser is directed to the entrance surface 11 of a second lens 15, and after being diffused by the second lens 15, a plurality of secondary lasers are emitted from the exit surface 12 of the second lens 15. The plurality of secondary lasers emitted after being diffused by each second lens 15 can form a surface array laser, and the surface array lasers formed after being diffused by the plurality of second lenses 15 can be combined to form a larger surface array laser to improve the diffusion range of the laser.

[0052] The emission system includes a laser emitter and a diffusion unit, the laser emitted by the laser emitter is incident from the entrance surface 11 of the lens 1 and emitted from the plurality of exit planes 121 on the exit surface 12, and the laser emitted from each exit plane 121 converges to form a laser beam. The plurality of laser beams emitted from the plurality of exit planes 121 of one lens 1 are first converged and then diffused to form a surface array laser. When the emission system includes multiple groups of laser emitters and diffusion units, the multiple groups of laser emitters and diffusion units are arranged in sequence, the laser emitters in a single group emit laser to the diffusion unit in the group, and the laser emitted to each diffusion unit can form a surface array laser after being diffused by the diffusion unit. The surface array lasers emitted from the plurality of diffusion units can be combined to form a larger surface array laser to expand the scanning range.

[0053] The emission system can be fixedly arranged and applied to a solid-state laser radar. The solid-state laser radar using the emission system is not prone to failure and has the advantages of stable structure and high reliability.

[0054] In other embodiments, the emission system also includes a rotator, on which both the laser emitter and the diffusion unit are mounted. When the rotator rotates or oscillates, it expands the scanning range of the area array laser emitted by the diffusion unit. The diffusion unit can diffuse a single laser beam into an area array laser with multiple exit points. Under the same scanning frequency, compared to traditional mechanical lidar, if the rotator rotates at the same speed, the lidar can obtain more scanning points and a larger scanning range after the rotator rotates because the number of exit points of the area array laser formed by the laser passing through the diffusion unit is greater, resulting in higher scanning accuracy. Furthermore, if the lidar has the same number of scanning points, the rotator in this embodiment can rotate at a lower speed because the number of exit points of the area array laser formed by the laser passing through the diffusion unit is greater, thus increasing the rotator's lifespan.

[0055] Regarding the diffusion unit provided by this invention, it should be noted that although it is applied to lidar in this embodiment, those skilled in the art can apply it to other optical fields without departing from the principle of the invention.

[0056] Example 2

[0057] The difference from Embodiment 1 is that lens 1 can directly convert the incident parallel light into diffused light and emit it.

[0058] Specifically, such as Figure 9 As shown, the incident surface 11 is a plane, and the base surface of the exit surface 12 is a concave arc surface. The exit surface 12 still includes multiple exit planes 121, and the arrangement of the exit planes 121 is the same as in Embodiment 1.

[0059] The laser beam is incident perpendicularly from the incident surface 11 and exits through multiple exit planes 121 on the exit surface 12. The laser beams emitted from each exit plane 121 converge into a single laser beam. The multiple laser beams emitted from the multiple exit planes 121 of the lens 1 diffuse outward directly and combine to form a laser array.

[0060] Regarding the shapes of the incident surface 11 and the exit surface 12, it should be noted that although the incident surface 11 is a plane and the base surface of the exit surface 12 is a concave curved surface in this embodiment, this is not a limitation of the present invention. Without departing from the principle of the present invention, in other embodiments, those skilled in the art can also set the incident surface 11 to be a concave curved surface and the base surface of the exit surface 12 to also be a concave curved surface. The laser enters from the incident surface 11 and exits from the exit surface 12, which can also convert a laser beam into a diffused laser beam.

[0061] The technical scheme of the present application has been described in combination with the preferred embodiments shown in the drawings, but it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical schemes after the changes or replacements will all fall within the protection scope of the present application.

Claims

1. A diffusion unit for a laser radar, comprising a lens (1) including an incident surface (11) and an exit surface (12), the base surface of the exit surface (12) being a curved surface, characterized in that: the exit surface (12) comprises a plurality of exit planes (121) arranged based on the base surface, the exit planes (121) being machined by means of removing material on the base surface of the exit surface (12), each of the exit planes (121) being an independent light exit point, and the included angle between any two exit planes (121) being greater than 0° and less than 180°; when a light beam is incident from the incident surface (11), the light beam is refracted by the lens (1) to exit from a plurality of the exit planes (121), and each of the exit planes (121) emits a single light beam which converges and then diffuses to form a planar array of light; the diffusion unit comprises a first lens (14) and a plurality of second lenses (15), the first lens (14) and the second lenses (15) are all identical in structure to the lens (1), and the plurality of exit planes (121) of the first lens (14) are arranged one by one in correspondence with the plurality of second lenses (15); when a light beam is incident from the incident surface (11) of the first lens (14), the light refracted by the exit planes (121) of the first lens (14) can be incident into the second lenses (15) and then refracted and emitted by the second lenses (15). the incident surface (11) is a plane, and the base surface is a convex surface; or the incident surface (11) and the base surface are both convex surfaces. the incident surface (11) is a plane, and the base surface is a concave surface; or the incident surface (11) and the base surface are both concave surfaces.

2. Diffusion unit according to claim 1, characterized in that the areas of all the exit planes (121) are the same; and / or the intervals between any two adjacent exit planes (121) are the same.

3. The diffusion unit of claim 1, wherein the lens (1) has a main optical axis (13), the base line of the exit surface (12) on a central section is a branch of a hyperbola, the base surface is obtained by rotating the base line around the main optical axis (13), and any one of the exit planes (121) is parallel to the tangent plane corresponding to the base surface. the edges of the exit planes (121) are provided with light shielding members (2).

4. The diffusion unit of claim 1, wherein The diffusion unit according to any one of claims 1 to 6; a laser emitter capable of emitting parallel laser light which is converted into diffuse light after being incident into the lens (1) from the incident surface (11).

5. The diffusion unit of claim 1, wherein The emission system further comprises a rotator, and the laser emitter and the diffusion unit are both mounted on the rotator.

6. The diffusion unit according to any one of claims 1 to 5, characterized in that The emission system according to claim 7 or 8.

7. A transmitting system characterized by, The laser radar according to claim 9. ​ ​ 8. The launch system of claim 7, wherein, ​ 9. A lidar, comprising: ​ 10. A vehicle characterized by comprising: ​

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