Transmit lens assembly, optical device, and lidar

Abstract

The application provides a transmitting lens assembly, an optical device and a laser radar, and relates to the technical field of laser radars; the transmitting lens assembly comprises a lenticular lens, a meniscus lens and a plurality of micro-lens arrays; the meniscus lens is arranged on the light-emitting direction of the lenticular lens and is spaced apart from the lenticular lens; at least one first light-in area is formed on the first light-in arc surface of the meniscus lens, and the plurality of micro-lens arrays are distributed on each first light-in area; a laser beam emitted by a scanning laser light source is incident into the lenticular lens, and each first light-in area corresponds to the laser beam; the lenticular lens emits the laser beam into the micro-lens array corresponding to the first light-in area; the micro-lens array on each first light-in area emits the incident light beam energy after homogenization and then emits the light beam to the meniscus lens; and the meniscus lens corrects the distortion of the incident light beam. The optical performance of the transmitting lens assembly in the application enables the emitted laser beam to have uniformity and stability.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to, but are not limited to, the technical field of laser radar, and particularly to a transmitting lens assembly, an optical device, and a laser radar. BACKGROUND

[0002] A laser radar (LiDAR) system is a key component in modern remote sensing technology, widely used in autonomous vehicles, unmanned aerial vehicles, topographic mapping, and other fields. Since the laser radar system measures the distance and speed of an object by emitting a laser pulse and receiving the reflected light, the performance of the laser radar system largely depends on the efficiency and accuracy of its optical components, especially the transmitting TX lens assembly at the transmitting end. In the prior art, the TX lens assembly usually faces several major challenges: first, the optical efficiency of the TX lens may be insufficient, resulting in excessive loss of emitted laser energy and affecting the ranging capability of the system; second, the optical design of the TX lens may not be sufficient to ensure uniform distribution of the laser beam; and third, the occurrence of bad points during the use of the laser chip can greatly affect the uniformity of the laser beam. Therefore, in the prior art, the optical performance of the TX lens assembly applied to the laser radar is poor. Based on this, how to provide a transmitting lens assembly applied to the laser radar to improve the optical performance is a technical problem to be solved. SUMMARY

[0003] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims. Embodiments of the present application provide a transmitting lens assembly, an optical device, and a laser radar, which can improve the optical performance of the transmitting lens assembly applied to the laser radar, so that the emitted laser beam has uniformity and stability.

[0004] In a first aspect, a transmitting lens assembly according to embodiments of the present application includes:

[0005] A lenticular lens;

[0006] A meniscus lens, the meniscus lens being located in the light-emitting direction of the lenticular lens and being arranged spaced apart from the lenticular lens; at least one first light-in area being formed on a first light-in arc surface of the meniscus lens,

[0007] A plurality of micro-lens arrays, the plurality of micro-lens arrays being arrayed on each of the first light-in areas;

[0008] The laser beam emitted by the scanning laser light source is incident on the lenticular lens, and the first light entry area corresponds to the scanning laser light source one by one; the lenticular lens emits the laser beam to the microlens in the corresponding first light entry area, and the microlens on each first light entry area emits the incident light beam energy to the meniscus lens after homogenization, and the meniscus lens corrects the distortion of the incident light beam.

[0009] Therefore, the above-mentioned embodiments of the present application have at least the following beneficial effects: the optical focusing can be realized by the lenticular lens and the meniscus lens, and the light beam energy homogenization of the light beam emitted by the lenticular lens can be realized by the microlens corresponding to the laser beam in the first light entry area of the meniscus lens, so that the uniformity of the energy of the light beam entering the meniscus lens can be improved, at this time, the lenticular lens can limit the field of view angle in the scanning direction, and the microlens can limit the field of view angle in the non-scanning direction, so that the light emitted by the meniscus lens can realize the homogenization of the light beam and the more concentrated energy. Therefore, compared with the related art, the optical performance of the emission lens assembly applied to the laser radar can be improved, so that the emitted laser beam has emission uniformity and stability.

[0010] According to some embodiments of the first aspect of the present application, the first light exit arc surface and the second light entry arc surface of the lenticular lens are both even aspheric surfaces.

[0011] According to some embodiments of the first aspect of the present application, the second light exit arc surface and the first light entry arc surface of the meniscus lens are both even aspheric surfaces.

[0012] According to some embodiments of the first aspect of the present application, the second light entry arc surface of the lenticular lens is provided with a plurality of second light entry areas, and each second light entry area corresponds to one scanning laser light source one by one; the lenticular lens is used for refracting the laser beam incident on each second light entry area to the corresponding first light entry area, and at least two first light entry areas partially overlap.

[0013] According to some embodiments of the first aspect of the present application, the total field of view angle in the scanning direction corresponding to the plurality of second light entry areas of the lenticular lens is greater than the total field of view angle in the non-scanning direction of each microlens.

[0014] According to some embodiments of the first aspect of the present application, the curvature of the first light entry arc surface is determined according to the expansion direction of the microlens and the field of view angle in the scanning direction of the lenticular lens, and the field of view angle in the scanning direction is arranged one by one corresponding to the first light entry area.

[0015] According to some embodiments of the first aspect of the present application, the ratio between the arc surface radius of the first light-entering arc surface and the second light-exiting arc surface of the meniscus cylindrical lens is 8:9; and / or;

[0016] The ratio between the thickness of the meniscus cylindrical lens and the thickness of the lenticular cylindrical lens is 2:3.3; and / or;

[0017] The ratio between the light source size of the scanning laser light source, the interval between the lenticular cylindrical lens and the meniscus cylindrical lens, and the thickness of the lenticular cylindrical lens is 3.4:3.1:3.3.

[0018] In a second aspect, an optical device is provided according to embodiments of the present application, including the emission lens assembly of any of the first aspect.

[0019] In a third aspect, a laser radar is provided according to embodiments of the present application, including:

[0020] A scanning laser light source;

[0021] The optical device of the second aspect, wherein the scanning laser light source is configured to provide a laser beam to the optical device. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings are included to provide a further understanding of the technical solutions of the present application, and constitute a part of the specification, and are used together with the embodiments of the present application to explain the technical solutions of the present application, and do not constitute a limitation on the technical solutions of the present application.

[0023] Figure 1 is a structural schematic diagram of an emission lens assembly according to an embodiment of the present application;

[0024] Figure 2 is a light path schematic diagram of the emission lens assembly in a scanning direction according to an embodiment of the present application;

[0025] Figure 3 is a light path schematic diagram of the emission lens assembly in a non-scanning direction according to an embodiment of the present application.

[0026] Reference signs:

[0027] a lenticular cylindrical lens 100,

[0028] a meniscus cylindrical lens 200,

[0029] a micro cylindrical lens 300. DETAILED DESCRIPTION

[0030] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and do not limit the present application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. The use herein of terms such as "first", "second", "third", "fourth", etc. (if any) are used merely to describe a distinction between like objects, and are not necessarily intended to describe a particular sequential or chronological order, unless specified.

[0032] Moreover, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the technology disclosed can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the disclosure.

[0033] Laser radar (LiDAR) systems are key components in modern remote sensing technology, widely used in autonomous vehicles, drones, topographic mapping, and other fields. Since laser radar systems measure the distance and speed of objects by emitting laser pulses and receiving the reflected light, the performance of laser radar systems largely depends on the efficiency and accuracy of their optical components, especially the transmitting TX lens assembly at the transmitting end. In the prior art, TX lens assemblies often face several major challenges: first, the optical efficiency of the TX lens may be insufficient, resulting in excessive loss of emitted laser energy and affecting the ranging ability of the system; second, the optical design of the TX lens may not be sufficient to ensure uniform distribution of the laser beam; and third, the occurrence of bad points during the use of the laser chip can greatly affect the uniformity of the laser beam. Therefore, in the prior art, the optical performance of the TX lens assembly applied to laser radar is poor. Based on this, how to provide a transmitting lens assembly applied to laser radar to improve the optical performance is a technical problem to be solved. Therefore, the embodiments of the present application provide a transmitting lens assembly, an optical device, and a laser radar, which can improve the optical performance of the transmitting lens assembly applied to laser radar, so that the emitted laser beam has emission uniformity and stability.

[0034] Reference is made below to Figures 1 to 3 The transmitting lens assembly of the embodiments of the present application is described, wherein, Figure 1 the arrow in the formula (1) indicates that the advancing direction of the light beam is from the biconical lens to the meniscus lens, Figure 2 and Figure 3a, b, c respectively represent different scanning laser light sources. The irradiation ranges of a, b, and c can be the same or different, and the irradiation angles of a, b, and c towards the lenticular lens are different from each other. The area enclosed by the line segments of the same type is the beam path of the same scanning laser light source.

[0035] In a first aspect, the application provides a transmitting lens assembly, which comprises:

[0036] a lenticular lens 100;

[0037] a meniscus lens 200, which is arranged in the light-emitting direction of the lenticular lens 100 and is spaced apart from the lenticular lens 100; at least one first light-in area is formed on the first light-in arc surface of the meniscus lens 200,

[0038] a plurality of micro-lens 300, which are arrayed on each first light-in area;

[0039] The laser beams emitted by the scanning laser light sources enter the lenticular lens 100, and the first light-in areas correspond one-to-one to the scanning laser light sources; the lenticular lens 100 emits the laser beams to the micro-lens 300 in the corresponding first light-in area, and the micro-lens 300 on each first light-in area homogenizes the incident beam energy and emits it to the meniscus lens 200, which corrects the distortion of the incident beam.

[0040] Therefore, the lenticular lens 100 and the meniscus lens 200 can realize optical focusing, and by arranging the micro-lens 300 corresponding to the laser beam in the first light-in area of the meniscus lens 200, the micro-lens 300 homogenizes the beam energy of the laser beams emitted by the lenticular lens 100, thereby improving the uniformity of the energy of the beams entering the meniscus lens 200. At this time, the lenticular lens 100 can limit the scanning direction field of view, and the micro-lens 300 can limit the non-scanning direction field of view, so that the light emitted by the meniscus lens 200 can realize beam homogenization and more concentrated energy. Therefore, the application can improve the optical performance of the transmitting lens assembly applied to the laser radar, so that the emitted laser beam has emission uniformity and stability.

[0041] The first light-out arc surface and the second light-in arc surface of the lenticular lens 100 are both convex cylindrical lenses, the cross section is in the shape of a “convex lens” (convex on both sides), and the axial (non-refractive) cross section is rectangular or straight. The lenticular lens 100 has curvature only in one direction (refractive direction), and the other direction (non-refractive direction) is flat or straight, and the effect on the incident beam has “one-dimensionality”.

[0042] The surface of the meniscus lens 200 consists of a convex second light-exiting arc surface and a concave first light-incident arc surface, with the centers of curvature of the two arc surfaces located on the same side of the lens. It has a certain length in one direction (i.e., the axial direction) and a specific radius of curvature in another direction (perpendicular to the axial direction) for specific refraction and focusing of light.

[0043] This application embodiment does not limit the number of scanning laser source refractions supported by the biconvex cylindrical lens 100; those skilled in the art can selectively set it according to actual needs. Different scanning laser sources have different second incident light regions entering through the second incident arc surface of the biconvex cylindrical lens 100. Each second incident light region is non-overlapping. The first and second incident light regions are set in a one-to-one correspondence. The biconvex cylindrical lens 100 is used to determine the field of view angle of the scanning laser source in the scanning direction, such as... Figure 2 As shown, when the laser beams from scanning laser sources a, b, and c from different regions are incident into their respective second incident light regions, the laser beams from each region are refracted after passing through the biconvex cylindrical lens 100. At this time, different scanning laser sources correspond to different field angles. The superposition of the field angles formed by the three different scanning laser sources forms the total field angle in the scanning direction.

[0044] This application does not limit the spacing between the meniscus lens 200 and the biconvex cylindrical lens 100. The radius of the front surface of the meniscus lens 200 and this spacing are set in a one-to-one correspondence. In some embodiments, the radius (R) of the front surface of the meniscus lens 200 and the spacing between it and the biconvex cylindrical lens 100 can be adjusted according to the distortion correction amount of the light emitted by the meniscus lens 200 to determine the distortion correction amount and the preset lens size of the meniscus lens 200 (such as the front surface radius and spacing of the meniscus lens 200). Different spacings correspond to different R values; the smaller the spacing, the smaller the size of the meniscus lens 200. In practical applications, the optical path of the meniscus lens 200 and the biconvex cylindrical lens 100 can be simulated to select the radius and spacing of the meniscus lens 200 that meet the distortion correction amount and lens size requirements. The R of the rear surface of the meniscus lens 200 is determined based on the lens thickness. In this embodiment, the meniscus lens 200 is a lens of uniform thickness. Therefore, the R of the rear surface of the meniscus lens 200 is equal to the R of the front surface plus the thickness.

[0045] The embodiments of this application can be applied to intelligent driving systems that assist in automatic parking of cars, obstacle avoidance by robots and drones, and short-range literacy scenarios.

[0046] The embodiments of the present application do not limit the interval distance between the microlens 300, and the plurality of microlenses 300 can divide the light beam emitted by the biconvex cylindrical lens 100 into sub-beams corresponding to the microlenses 300. The microlenses 300 are arranged continuously, and the smaller the aperture of the microlenses 300, the more sub-beams are divided, and the light emission is more uniform. Therefore, after the size of the meniscus cylindrical lens 200 and the interval between the meniscus cylindrical lens 200 and the biconvex cylindrical lens 100 are determined, the aperture of the microlens 300 can be determined by simulation, so that the emission lens assembly of the embodiments of the present application can meet the uniformity of the emitted light.

[0047] It can be understood that the first light-out arc surface and the second light-in arc surface of the biconvex cylindrical lens 100 are both even aspheric surfaces.

[0048] By setting the first light-out arc surface and the second light-in arc surface as even aspheric surfaces, the aberration between the light rays in the scanning direction can be reduced, and the stability of the optical performance can be improved.

[0049] It can be understood that the second light-out arc surface and the first light-in arc surface of the meniscus cylindrical lens 200 are both even aspheric surfaces.

[0050] The second light-in arc surface is the arc surface on the light incidence direction side, and the first light-out arc surface is the arc surface on the light emission direction side.

[0051] By setting the second light-out arc surface and the first light-in arc surface as even aspheric surfaces, the aberration between the light rays in the non-scanning direction can be reduced, and the stability of the optical performance can be further improved.

[0052] It can be understood that the second light-in arc surface of the biconvex cylindrical lens 100 is provided with a plurality of second light-in regions, and each second light-in region corresponds to one laser beam; the biconvex cylindrical lens 100 is used to refract the laser beams incident on each second light-in region to the corresponding first light-in region, wherein at least two first light-in regions partially overlap.

[0053] By providing a plurality of second light-in regions on the biconvex cylindrical lens 100, the laser beams of the scanning laser light source with different illumination angles can be supported to be incident, and at the same time, the biconvex cylindrical lens 100 refracts each laser beam into different first light-in regions, thereby improving the light efficiency.

[0054] The embodiments of the present application do not limit how the first light-in regions are distributed, and a person skilled in the art can selectively set according to actual needs.

[0055] It can be understood that the total field of view in the scanning direction corresponding to the plurality of second light-in regions of the biconvex cylindrical lens 100 is greater than the total field of view in the non-scanning direction of each microlens 300.

[0056] It can be understood that the curvature of the first light-incident arc surface is determined according to the expansion direction of the micro-lens 300 and the scanning direction field of view of the bi-convex cylindrical lens 100, wherein the scanning direction field of view is arranged in one-to-one correspondence with the first light-incident region.

[0057] Since the micro-lens 300 is arranged on the first light-incident arc surface, and the expansion direction of the micro-lens 300 changes with the curvature of the first light-incident arc surface, the performance of the light beam can be determined by simulating the movement of the light beam in the process of adjusting the curvature of the first light-incident arc surface, and the curvature of the first light-incident arc surface meeting the performance is selected.

[0058] It can be understood that the ratio between the arc surface radii of the first light-incident arc surface and the second light-emitting arc surface of the meniscus cylindrical lens 200 is 8:9; and / or;

[0059] The ratio between the thickness of the meniscus cylindrical lens 200 and the thickness of the bi-convex cylindrical lens 100 is 2:3.3; and / or;

[0060] The ratio between the distance between the light source size, the bi-convex cylindrical lens 100 and the meniscus cylindrical lens 200 and the thickness of the bi-convex cylindrical lens 100 is 3.4:3.1:3.3.

[0061] The person skilled in the art can select one or more of the following conditions according to actual needs: the ratio between the arc surface radii of the first light-incident arc surface and the second light-emitting arc surface of the meniscus cylindrical lens 200 is 8:9, the ratio between the thickness of the meniscus cylindrical lens 200 and the thickness of the bi-convex cylindrical lens 100 is 2:3.3, and the ratio between the distance between the light source size, the bi-convex cylindrical lens 100 and the meniscus cylindrical lens 200 and the thickness of the bi-convex cylindrical lens 100 is 3.4:3.1:3.3 to obtain the emission lens assembly of the embodiment of the application.

[0062] For example, referring to FIG. 6, the lens group with a field of view FOV of 112°*70° is taken as an example, wherein the scanning direction field of view is 112° and the non-scanning direction field of view is 70°. Figure 2 The bi-convex cylindrical lens 100 controls the FOV in the scanning direction, and the FOV in the scanning direction is related to the light source size of the scanning light source. The focal length of the bi-convex cylindrical lens 100 and the light source size together determine the FOV in the scanning direction of the lens group. Based on this feature, the bi-convex cylindrical lens 100 is optimized. For example, the light source size in the scanning direction of the light source is 3.4 mm, and the initial structure focal length is 2.3 mm. Then, by optimizing the parameters of the bi-convex cylindrical lens 100, the light sources in different regions on the light source chip are combined into a 112° field of view after being emitted by the different laser beams after passing through the bi-convex cylindrical lens 100. At this time, the size of the bi-convex cylindrical lens 100 is determined to be 6*6 mm, and the thickness is 3.3 mm.

[0063] For example, the field of view FOV of the lens group is 112°*70°, the scanning direction field of view is 112°, and the non-scanning direction field of view is 70°. For example, referring to FIG. 2A, Figure 3 As shown in FIG. 2B, the first light-incident curved surface of the meniscus cylindrical lens 200 is arranged with micro-cylindrical lenses 300 along the curved direction, the aperture of the micro-cylindrical lens 300 is 100 um, the light beam is divided into several sub-beams by the array of micro-cylindrical lenses 300, so that each sub-beam has a FOV greater than 70° and uniform energy distribution after passing through the micro-cylindrical lens 300, and then superimposed to realize homogenization in the non-scanning direction and the field of view requirement. The spacing between the meniscus cylindrical lens 200 and the biconvex cylindrical lens 100 is 3.1 mm, and at the same time, the R of the first light-incident curved surface of the biconvex cylindrical lens 100 is 16 mm, the R of the second light-incident curved surface is 18 mm, and the thickness is 2 mm. At this time, the light path of the emission lens assembly in the non-scanning direction is as shown in FIG. 2C. Figure 3 As shown in FIG. 2B, the first light-incident curved surface of the meniscus cylindrical lens 200 is arranged with micro-cylindrical lenses 300 along the curved direction, the aperture of the micro-cylindrical lens 300 is 100 um, the light beam is divided into several sub-beams by the array of micro-cylindrical lenses 300, so that each sub-beam has a FOV greater than 70° and uniform energy distribution after passing through the micro-cylindrical lens 300, and then superimposed to realize homogenization in the non-scanning direction and the field of view requirement. The spacing between the meniscus cylindrical lens 200 and the biconvex cylindrical lens 100 is 3.1 mm, and at the same time, the R of the first light-incident curved surface of the biconvex cylindrical lens 100 is 16 mm, the R of the second light-incident curved surface is 18 mm, and the thickness is 2 mm. At this time, the light path of the emission lens assembly in the non-scanning direction is as shown in FIG. 2C.

[0064] Based on the above Figure 2 and Figure 3 of the examples of the present application, the light performance test is carried out, the uniformity of the light spot in the middle partition angle space is 53%, the window efficiency is 69%, the uniformity of the light spot in the edge partition angle space is 33%, and the window efficiency is 59%.

[0065] It can be understood that the optical device according to the embodiment of the present application comprises any one of the above emission lens assemblies.

[0066] It can be understood that the laser radar according to the embodiment of the present application comprises:

[0067] The scanning laser light source;

[0068] The optical device as described above, the scanning laser light source is used to provide a laser beam to the optical device.

[0069] The above is a specific description of the preferred embodiment of the present application, but the present application is not limited to the above-mentioned embodiments, those skilled in the art can make various equivalent modifications or replacements without departing from the spirit of the present application, and these equivalent modifications or replacements are all included in the scope defined by the claims of the present application.

Claims

1. A transmitting lens assembly, characterized in that, The transmitting lens assembly consists of a biconvex cylindrical lens, a meniscus lens, and multiple microcylindrical lenses; wherein... The meniscus lens is located in the light-emitting direction of the biconvex cylindrical lens and is spaced apart from the biconvex cylindrical lens; at least one first light-incident region is formed on the first light-incident arc surface of the meniscus lens. The plurality of micropillar lens arrays are distributed on each of the first incident light regions; In this process, a laser beam emitted from a scanning laser source enters the biconvex cylindrical lens, and the first incident light area corresponds one-to-one with the scanning laser source. The biconvex cylindrical lens directs the laser beam to micro-cylindrical lenses within the corresponding first incident light areas. Each micro-cylindrical lens in the first incident light area homogenizes the energy of the incident beam before directing it to the meniscus lens, which corrects the distortion of the incident beam. Wherein, the ratio between the radii of the first incident arc surface and the second exit arc surface of the meniscus lens is 8:9; and / or; the ratio between the thickness of the meniscus lens and the thickness of the biconvex cylindrical lens is 2:3.3; and / or; the ratio between the light source size of the scanning laser source, the distance between the biconvex cylindrical lens and the meniscus lens, and the thickness of the biconvex cylindrical lens is 3.4:3.1:3.

3.

2. The transmitting lens assembly according to claim 1, characterized in that, The first light-emitting arc surface and the second light-receiving arc surface of the biconvex cylindrical lens are both even-order aspherical surfaces.

3. The transmitting lens assembly according to claim 1 or 2, characterized in that, The second light-emitting arc surface and the first light-incident arc surface of the meniscus lens are both even-order aspherical surfaces.

4. The transmitting lens assembly according to claim 1, characterized in that, The second incident light arc surface of the biconvex cylindrical lens is provided with a plurality of second incident light regions, each of which corresponds to a scanning laser source; the biconvex cylindrical lens is used to refract the laser beam incident on each of the second incident light regions to the corresponding first incident light region, wherein at least two of the first incident light regions partially overlap.

5. The transmitting lens assembly according to claim 4, characterized in that, The total field of view in the scanning direction corresponding to the multiple second incident light regions of the biconvex cylindrical lens is greater than the total field of view in the non-scanning direction of each of the micro cylindrical lenses.

6. The transmitting lens assembly according to claim 1, characterized in that, The curvature of the first incident light arc surface is determined based on the expansion direction of the micropillar lens and the scanning direction field of view of the biconvex cylindrical lens, wherein the scanning direction field of view is set in a one-to-one correspondence with the first incident light region.

7. An optical device, characterized in that, Includes the transmitting lens assembly as described in any one of claims 1 to 6.

8. A lidar, characterized in that, include: Scanning laser source; The optical device of claim 7, wherein the scanning laser source is used to provide a laser beam to the optical device.

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