Transmitters and lidars for lidar

Abstract

The present disclosure provides a transmitter and a laser radar for a laser radar. The transmitter according to the present disclosure includes: a laser surface light source, which emits an initial light beam with an initial divergence angle; a first super lens, through which the initial light beam passes, so that the initial light beam with an initial divergence angle is transformed into a first light beam with a first divergence angle; a second super lens, through which the first light beam passes, so that the first light beam with a first divergence angle is transformed into a second light beam with a second divergence angle, and the second light beam is used to generate a point cloud or multi-line in the far field, wherein the first super lens is located between the second super lens and the laser surface light source, and wherein the first divergence angle is smaller than the initial divergence angle, and the second divergence angle is smaller than the first divergence angle. The transmitter for a laser radar according to the present disclosure and the laser radar including the same have the advantages of simple structure, small size, low cost, and long life.

Description

Technical Field

[0001] The present disclosure relates to the technical field of optical metalenses, and in particular, to a transmitter for a laser radar and a laser radar. Background Art

[0002] LiDAR is a scanning sensor that uses non-contact laser ranging technology. Its working principle is similar to that of a general radar system, that is, it detects targets by emitting laser beams and collects reflected beams to form point clouds and obtain data. These data can be generated into accurate three-dimensional images after photoelectric processing. This technology can accurately obtain high-precision physical space environment information, and the ranging accuracy can reach the centimeter level. Therefore, LiDAR has extremely wide applications as a basic component in scientific and industrial fields such as autonomous driving, precision modeling, and three-dimensional remote sensing.

[0003] The laser radar is mainly composed of a transmitter, a receiver, a signal processing unit and a display unit. Furthermore, the transmitter mainly includes a laser source, an optical modulation module, a beam control module and a scanning control module. Specifically, the laser emitted by the laser source is optically modulated and beam controlled by the optical modulation module and the beam control module, and then projected into the space under the control of the scanning control module, so that the laser beam scans in the space in a specific way. When the laser beam irradiates the target, scattering occurs, and the scattered photoelectric signal is received by the receiver of the laser radar, and then converted into an electrical signal by the signal processing unit and amplified and processed, so that the target signal is displayed on the display unit.

[0004] The scanning control module of the traditional laser radar transmitter is mainly implemented by mechanical scanning module and MEMS micro-seismic mirror scanning module. However, the transmitter of non-mechanical scanning laser radar has reduced the hardware cost and wear consumption to a certain extent because it does not have rotating components, and it can continue to work even if individual components in the light source array are damaged, which greatly improves the reliability and has therefore received widespread attention.

[0005] A superlens is a planar lens manufactured by a semiconductor process, which has the advantages of small size (thin thickness), light weight, simple structure, low cost, and high production capacity. Due to the above advantages, superlenses can also be used in the transmitter of a laser radar. However, in the prior art, superlenses are only used to collimate lasers in the transmitter of a laser radar, and the generation of multiple lines still requires multiple laser light sources arranged in a predetermined orientation, and the generation of far-field point clouds still requires diffractive optical elements, which does not give full play to the advantages of the superlens described above.

[0006] Therefore, there is still a need for a non-mechanical scanning laser radar transmitter that can fully utilize the advantages of superlens. Summary of the invention

[0007] A brief summary of the disclosure is given below in order to provide a basic understanding of certain aspects of the disclosure. However, it should be understood that this summary is not an exhaustive summary of the disclosure, nor is it intended to identify the key or important parts of the disclosure, nor is it intended to limit the scope of the disclosure. The purpose of this summary is only to present certain inventive concepts of the disclosure in a simplified form as a prelude to a more detailed description given later.

[0008] The present disclosure aims to provide a transmitter for a laser radar based on a metalens and a laser radar using the transmitter.

[0009] According to one aspect of the present disclosure, a transmitter for a laser radar is provided, comprising: a laser surface light source, emitting an initial light beam with an initial divergence angle; a first super lens, through which the initial light beam passes, so that the initial light beam with the initial divergence angle is transformed into a first light beam with a first divergence angle; a second super lens, through which the first light beam passes, so that the first light beam with the first divergence angle is transformed into a second light beam with a second divergence angle, the second light beam being used to generate a point cloud or multi-lines in a far field, wherein the first super lens is located between the second super lens and the laser surface light source, and wherein the first divergence angle is smaller than the initial divergence angle, and the second divergence angle is smaller than the first divergence angle.

[0010] According to an embodiment of the present disclosure, a ratio between the first divergence angle and the initial divergence angle is less than 1 / 5.

[0011] According to an embodiment of the present disclosure, the second divergence angle is determined by the farthest working distance of the laser radar and the minimum size of a target detectable at the farthest working distance.

[0012] According to an embodiment of the present disclosure, the laser surface light source includes a plurality of laser source arrays, and each laser source array is composed of a plurality of laser sources.

[0013] According to an embodiment of the present disclosure, a plurality of laser light source arrays are lit up in sequence in a predetermined order.

[0014] According to an embodiment of the present disclosure, a plurality of laser light source arrays are randomly lit.

[0015] According to an embodiment of the present disclosure, among the plurality of laser light source arrays, the number of times the laser light source array corresponding to the central field of view is lit is greater than the number of times the laser light source array corresponding to the outside of the central field of view is lit.

[0016] According to an embodiment of the present disclosure, each of the first superlens and the second superlens includes a substrate and a microstructure layer disposed on the substrate, and wherein the microstructure layer includes microstructure units arranged in an array.

[0017] According to an embodiment of the present disclosure, the size and shape of the microstructure unit are determined according to the operating band of the laser radar.

[0018] According to an embodiment of the present disclosure, a point cloud or multi-lines is generated in the far field by adjusting the phase of the initial light beam.

[0019] According to another aspect of the present disclosure, a laser radar is provided, which includes a transmitter according to the above aspects of the present disclosure.

[0020] According to the technical solution of the present disclosure, a metalens can be used to simultaneously realize the function of generating a far-field point cloud or multi-line and the function of beam collimation, thereby reducing the number of lenses in the transmitter, thereby reducing the overall volume, weight and cost of the laser radar. In addition, according to the technical solution of the present disclosure, a laser surface light source composed of a laser source array can be used to realize a non-mechanical scanning transmitter, thereby reducing the complexity of the transmitter while increasing the overall service life of the laser radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The accompanying drawings illustrate embodiments of the present disclosure and together with the following description serve to explain the principles of the present disclosure.

[0022] Figure 1 A schematic diagram showing the configuration of a transmitter for a lidar according to an embodiment of the present disclosure.

[0023] Figure 2 A plan view of a laser surface light source according to an embodiment of the present disclosure is shown.

[0024] FIG. 3A to FIG. 3D A schematic diagram showing an example of sequentially lighting up a laser light source array included in a laser surface light source according to an embodiment of the present disclosure.

[0025] Figure 4A and Figure 4B A perspective view of one microstructure unit of a first superlens and a second superlens according to an embodiment of the present disclosure is shown.

[0026] Figure 5A and Figure 5B Plan views of microstructure layers of a first metalens and a second metalens according to embodiments of the present disclosure are shown.

[0027] FIG. 6A to FIG. 6C A schematic diagram showing the configuration of a transmitter for a lidar according to an alternative embodiment of the present disclosure.

[0028] Figure 7A schematic diagram of the configuration of a transmitter 700 for a lidar according to an example of the present disclosure is shown.

[0029] Fig. 8A The relationship between the focal plane spot size and the field of view angle is shown when the point cloud phase is not considered.

[0030] Figure 8B Shown with Fig. 8A The corresponding modulation transfer function curve.

[0031] Fig. 9A shows a phase diagram of a first metalens according to an example of the present disclosure, Fig. 9B shows a phase diagram of a second metalens according to an example of the present disclosure, and Fig. 9C A simulation diagram of a point cloud of 256 points projected at the far field is shown according to an example of the present disclosure.

[0032] Fig.10 A graph showing the relationship between the transmittance and phase of the nano-square pillars and the side length of the nano-square pillars in an operating band of 905 nm according to an example of the present disclosure. DETAILED DESCRIPTION

[0033] The present disclosure will now be described more fully below with reference to the accompanying drawings, in which various embodiments are shown. However, the present disclosure can be implemented in many different ways and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure will be exhaustive and complete, and will fully convey the scope of the present disclosure to those skilled in the art. The same reference numerals throughout the text represent the same components. Furthermore, in the accompanying drawings, the thickness, ratios, and sizes of the components are exaggerated for clarity.

[0034] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, "one", "the", "at least one" as used herein do not represent a limitation on quantity, but are intended to include both the singular and the plural. For example, unless the context clearly indicates otherwise, "a component" has the same meaning as "at least one component". "At least one" should not be interpreted as being limited to the number "one". "Or" means "and / or". The term "and / or" includes any and all combinations of one or more of the associated listed items.

[0035] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meanings as those generally understood by those skilled in the art. Terms defined in commonly used dictionaries should be interpreted as having the same meanings as in the relevant technical context, and unless explicitly defined in the specification, these terms are not interpreted as having formal meanings in an idealized or overly formal sense.

[0036] The meaning of “include” or “comprising” specifies properties, quantities, steps, operations, components, parts or a combination thereof, but does not exclude other properties, quantities, steps, operations, components, parts or a combination thereof.

[0037] Embodiments are described herein with reference to cross-sectional views as idealized embodiments. Thus, variations in shape relative to the illustrated diagram are anticipated as a result of, for example, manufacturing techniques and / or tolerances. Therefore, the embodiments described herein should not be interpreted as being limited to the specific shapes of the regions as shown herein, but should include deviations in shape due to, for example, manufacturing. For example, a region shown or described as flat may typically have rough and / or nonlinear features. Moreover, the sharp angles shown may be rounded. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to illustrate the precise shape of the regions and are not intended to limit the scope of the claims.

[0038] Hereinafter, exemplary embodiments according to the present disclosure will be described with reference to the accompanying drawings.

[0039] Figure 1 A schematic diagram showing the configuration of a transmitter 100 for a laser radar according to an embodiment of the present disclosure is shown.

[0040] like Figure 1 As shown, the transmitter 100 for laser radar according to the present disclosure includes: a laser surface light source 101, which emits a laser beam having an initial divergence angle θ 0 The initial beam L 0 ; First super lens 102, initial light beam L 0 Through the first super lens 102, the initial divergence angle θ 0 The initial beam L 0 is transformed into a first divergence angle θ 1 The first beam L 1 ; Second super lens 103, first light beam L 1 Through the second super lens 103, the first divergence angle θ 1 The first beam L 1 is transformed into a second divergence angle θ 2 The second beam L 2 , the second beam L 2For generating a point cloud or multi-line in the far field, wherein the first metalens 102 is located between the second metalens 103 and the laser surface light source 101, and wherein the first divergence angle L 1 Smaller than the initial divergence angle L 0 , and the second divergence angle θ 2 Less than the first divergence angle θ 1 As will be described in further detail below, the second divergence angle θ 2 Very small, close to zero degrees, that is, the second beam L 2 Approximately parallel light, so in Figure 1 The second divergence angle θ is not clearly marked 2 The specific location.

[0041] Figure 2 A plan view of a laser surface light source 101 according to an embodiment of the present disclosure is shown.

[0042] According to an embodiment of the present disclosure, the laser surface light source 101 includes a plurality of laser source arrays, each of which is composed of a plurality of laser sources.

[0043] Specifically, Figure 2 As shown, the laser surface light source 101 may be in the form of a laser source array. According to an embodiment of the present disclosure, the laser surface light source 101 may include N laser source arrays 101-i with the same structure, where 1≤i≤N. Preferably, N is the square of a natural number greater than 1, such as 4, 9, 16, 25, etc. For example, Figure 2 The laser surface light source 101 in the embodiment includes 5×5 (ie, N=25) laser source arrays 101 - 1 to 101 - 25. According to an embodiment of the present disclosure, each laser source array is composed of a plurality of laser sources.

[0044] According to an embodiment of the present disclosure, each laser source array may include M laser sources of the same structure, where M is a natural number greater than 1. Figure 2 As shown in , each laser source array may include, for example, 4×4 (ie, M=16) laser sources. According to an embodiment of the present disclosure, each laser source array 101-i may also include a greater or lesser number of laser sources. Figure 2 The laser sources in each laser source array 101 - i are shown to be arranged in the form of a square, but the present disclosure is not limited thereto, and the laser sources in each laser source array 101 - i may also be arranged in the form of a regular hexagon, or in the form of other shapes having spatial symmetry.

[0045] like Figure 1As shown in , the laser emitted by the laser surface light source 101 is compressed and collimated by the first super lens 102 and the second super lens 103 to generate a point cloud or multiple lines in the far field. Since the laser sources located at different positions on the laser surface light source 101 correspond to different emission angles at the second super lens 103, and thus correspond to different field of view angles in the far field, the laser beam emitted by the laser source located at the non-central field of view of the laser surface light source 101 corresponds to the obliquely emitted far-field parallel light and the corresponding point cloud or multiple lines. For example, Figure 1 As shown, the laser emitted by the laser source at the center position 1 of the field of view of the laser surface light source 101 has a field of view angle of 0° relative to the direction perpendicular to the laser surface light source 101 after passing through the second super lens 103. The laser emitted by the laser source at the position 2 deviating from the center of the field of view of the laser surface light source 101 has a field of view angle of 15° relative to the direction perpendicular to the laser surface light source 101 after passing through the second super lens 103. In addition, the laser emitted by the laser source at the position 3 away from the center of the field of view of the laser surface light source 101 has a field of view angle of 30° relative to the direction perpendicular to the laser surface light source 101 after passing through the second super lens 103.

[0046] Therefore, according to the embodiment of the present disclosure, the plurality of laser source arrays 101-i included in the laser surface light source 101 are sequentially lit. In other words, since the laser source of the non-central field of view of the laser surface light source 101 corresponds to the obliquely emitted far-field parallel light and the corresponding point cloud or multi-line, the laser source arrays included in the laser surface light source 101 can be used to sequentially light up to scan in the far field.

[0047] FIG. 3A to FIG. 3D A schematic diagram showing an example of lighting the laser source array 101 - i included in the laser surface light source 101 according to an embodiment of the present disclosure.

[0048] According to an embodiment of the present disclosure, a plurality of laser source arrays 101-i are lit up in a predetermined order. Figure 3A As shown by the arrows in FIG. 1 , the laser source array 101 - i can be lit up in sequence in an S-shaped manner in the horizontal direction. Figure 3B As shown by the arrows in , the laser source array 101-i can be lit up in sequence in an S-shaped manner in the vertical direction. Figure 3C As shown by the arrows in FIG. 1 , the laser source arrays 101 - i can be lit up in sequence in a spiral manner starting from the laser source array at the center of the field of view. After each of the laser source arrays 101 - i is lit up once, a scanning cycle is completed, and then the next scanning cycle begins.

[0049] Those skilled in the art should realize that the lighting method of the laser source array 101-i included in the laser surface light source 101, that is, the scanning method is not limited to FIG. 3A to FIG. 3C In the example shown in , according to an embodiment of the present disclosure, the laser source arrays 101 - i may also be lit up in sequence in other set orders.

[0050] In addition, according to an embodiment of the present disclosure, the plurality of laser source arrays 101-i may also be randomly lit. Specifically, in one scanning cycle, the plurality of laser source arrays 101-i may be lit in a random order, as long as each of the plurality of laser source arrays 101-i is lit once. After each of all the laser source arrays 101-i is lit once, one scanning cycle is completed, and then the next scanning cycle begins.

[0051] According to an embodiment of the present disclosure, among the plurality of laser source arrays 101 - i, the number of times the laser source array corresponding to the central field of view is lit is greater than the number of times the laser source array corresponding to the outside of the central field of view is lit. Figure 3D As shown, the laser source array corresponding to the central field of view area in the laser source array 101-i included in the laser surface light source 103 is marked by a dotted frame. In order to ensure that the laser radar has a sufficient refresh frequency for the central field of view in front, the central field of view needs to be scanned multiple times in each scanning cycle. Therefore, according to an embodiment of the present disclosure, the number of times the laser source array outside the central field of view (outside the dotted frame) is lit can be set to 1 in each scanning cycle, and the number of times the laser source array inside the central field of view (inside the dotted frame) is lit is set to m, where m is a natural number greater than or equal to 2. According to an embodiment of the present disclosure, in each scanning cycle, the laser source array 101-i can be lit in a pre-set order, wherein the laser source array outside the central field of view is only lit once, and the laser source array inside the central field of view is lit m times. This scanning method of different lighting times (frequencies) of laser source arrays at different positions can ensure that the laser radar has a sufficient refresh frequency for the central field of view in front.

[0052] According to an embodiment of the present disclosure, the multiple laser source arrays 101-i included in the laser surface light source 101 can also be randomly lit, as long as the number of times the laser source array corresponding to the central field of view is lit is greater than the number of times the laser source array corresponding to the outside of the central field of view is lit. This can reduce the crosstalk problem of point cloud data in similar fields of view that may be caused by lighting the laser source arrays in sequence.

[0053] Next, the first super lens 102 and the second super lens 103 according to the embodiment of the present disclosure are described in more detail.

[0054] Metalenses are a specific application of metasurfaces. Metasurfaces are a subwavelength artificial nanostructured film that can modulate incident light based on the metasurface microstructure units on it. The metasurface microstructure units contain all-dielectric or plasmonic nanoantennas that can directly control the phase, amplitude, and polarization of light.

[0055] Figure 4A and Figure 4B A perspective view of one microstructure unit of the first superlens 102 and the second superlens 103 according to an embodiment of the present disclosure is shown. Figure 5A and Figure 5B A plan view of the microstructure layers of the first superlens 102 and the second superlens 103 according to an embodiment of the present disclosure is shown.

[0056] like Figure 4A and Figure 4B As shown, according to an embodiment of the present disclosure, each of the first superlens 102 and the second superlens 103 includes a substrate and a microstructure layer disposed on the substrate, wherein the microstructure layer includes microstructure units arranged in an array.

[0057] like Figure 5A As shown, according to the embodiment of the present disclosure, the microstructure units can be arranged in a regular hexagonal array. Figure 5B As shown, according to an embodiment of the present disclosure, the microstructure units can be arranged in a square array. Those skilled in the art should recognize that the microstructure units included in the microstructure layer can also include other forms of array arrangements, and all these variations are included in the scope of the present disclosure.

[0058] According to an embodiment of the present disclosure, the microstructure unit may have a nanostructure. Figure 4A and Figure 4B As shown, according to an embodiment of the present disclosure, a nanostructure is respectively arranged at the center position and / or the vertex position of each microstructure unit. According to an embodiment of the present disclosure, the nanostructure is an all-medium structure unit. According to an embodiment of the present disclosure, the nanostructure has high transmittance in the near-infrared light band. According to an embodiment of the present disclosure, the nanostructure can be formed of at least one of the following materials: titanium oxide, silicon nitride, fused quartz, aluminum oxide, gallium nitride, gallium phosphide, amorphous silicon, crystalline silicon, hydrogenated amorphous silicon, etc.

[0059] The nanostructures in the microstructure units of the metalens may be in the form of nanopillars. Figure 4A The cross-section of the nanorods shown in is circular, and Figure 4B The cross section of the nanorod shown in FIG. 1 is a square, but the present disclosure is not limited thereto. The nanostructure may also adopt other forms of structures, and all such variations are within the scope of the present disclosure.

[0060] According to an embodiment of the present disclosure, the size and shape of the microstructure unit are determined according to the working band of the laser radar. That is to say, the working band of the first super lens 102 and the second super lens 103 is a wavelength band commonly used in laser radar, including 850nm, 905nm, 940nm, 1550nm, etc. According to an embodiment of the present disclosure, air or other materials that are transparent or translucent in the working band can be filled between each nanostructure. According to an embodiment of the present disclosure, the absolute value of the difference between the refractive index of the filled material and the refractive index of the nanostructure should be greater than or equal to 0.5.

[0061] like Figure 1 As shown in FIG. 1 , the first super lens 102 can transmit the laser surface light source 101 with an initial divergence angle θ 0 The initial beam L 0 Compressed to have a first divergence angle θ 1 The first beam L 1 According to an embodiment of the present disclosure, the first divergence angle θ 1 With the initial divergence angle θ 0 The ratio between them is less than 1 / 5. In addition, according to the embodiment of the present disclosure, the phase on the first metalens 102 The aberration of the convergence phase of the second super lens 103 can be corrected.

[0062] In addition, according to an embodiment of the present disclosure, the laser surface light source 101 is disposed near the focal plane of the first super lens 102. Specifically, according to an embodiment of the present disclosure, the distance between the laser surface light source 101 and the first super lens 102 should be less than the focal depth of the first super lens 102. The focal depth Δf of the first super lens 102 can be determined by the following formula (1).

[0063] Δf=±2λ c F 2 (1)

[0064] where λ c is the central wavelength of the laser beam, and F is the F number of the first superlens 102, which is calculated by dividing the focal length of the first superlens 102 by the aperture of the first superlens 102.

[0065] In addition, if Figure 1 As shown in FIG. 1 , the second super lens 103 can transmit light having a first divergence angle θ transmitted through the first super lens 102. 1 The first beam L 1 Further compressed to have a second divergence angle θ 2 The second beam L 2 According to an embodiment of the present disclosure, the second light beam L 2 Used to generate point clouds or multi-lines in the far field, so the second divergence angle θ 2 The following formula (2) should be satisfied.

[0066] θ 2 ·L≤d (2)

[0067] Wherein, L is the maximum working distance of the laser radar, and d is the minimum size of the target that can be detected at the maximum working distance L. That is, according to the embodiment of the present disclosure, the second divergence angle θ 2 It is determined by the farthest working distance of the laser radar and the minimum size of the target that can be detected at the farthest working distance. Usually, the farthest working distance L is much larger than the minimum size d of the target that can be detected at the farthest working distance L, so the second divergence angle θ 2 Very small (approximately zero, so not in Figure 1 ), so that the second light beam L 2 Approximately parallel light.

[0068] As described above, the second super lens 103 has the function of compressing and collimating the light beam. Specifically, the phase required for the function of the second super lens 103 to compress the divergence angle of the laser beam is The corresponding phase can be calculated by inversely deriving the parallel light with the maximum field angle in the far field incident on the laser surface light source 101

[0069] In addition, according to the embodiment of the present disclosure, the second metalens 103 also has the function of generating a point cloud or multi-line in the far field. Specifically, the laser beams emitted by the laser source array at different positions in the laser surface light source 101 are added to generate a phase of a point cloud or multi-line in the far field.

[0070] In summary, considering the above two functions of the second super lens 103, the phase It can be calculated by the following formula (3).

[0071]

[0072] Among them, mod() is the remainder function. It can be given by a point cloud or a multi-line pattern combined with a GS algorithm as a phase recovery method. Since the phase control method of the laser radar is known to those skilled in the art, its details are not described in more detail herein.

[0073] Therefore, according to an embodiment of the present disclosure, a point cloud or multi-lines may be generated in the far field by adjusting the phase of the initial light beam.

[0074] In addition, according to the embodiment of the present disclosure, the aperture of the second super lens 103 is smaller than that of the first super lens 102. This is determined by the functions of the first super lens 102 and the second super lens 103. Specifically, the first super lens 102 directly faces the laser surface light source 101, and is used to direct the laser light source 101 with a larger initial divergence angle θ to the laser surface light source 101. 0 The initial beam L 0 Compressed to have a first divergence angle θ 1 The first beam L 1 , considering the initial divergence angle θ 0 The size of the first super lens 102, the distance between the laser surface light source 101 and the first super lens 102, and the plane size of the laser surface light source 101, the first super lens 102 has a larger diameter. In contrast, the second super lens 103 is used to further reduce the first divergence angle θ 1 Compressed into the second divergence angle θ 2 And point clouds or multi-lines are generated in the far field. Figure 1 As shown, after the light beam passes through the first super lens 102 , the laser beams emitted by the laser source array at different positions on the laser surface light source 101 need to converge to the same position, so the aperture of the second super lens 103 is smaller than the aperture of the first super lens 102 .

[0075] Those skilled in the art will recognize that although Figure 1 , the first superlens 102 and the second superlens 103 are shown as having the same orientation of their microstructure layers, that is, the microstructure layers of the first superlens 102 and the second superlens 103 both face the laser surface light source 101, but the present disclosure is not limited thereto. FIG. 6A to FIG. 6C FIG. 1 is a schematic diagram showing a configuration of a transmitter 100 for a laser radar according to an alternative embodiment of the present disclosure. FIG. 6A to FIG. 6C As shown, the orientations of the microstructure layers of the first superlens 102 and the second superlens 103 can be arbitrarily set, and all such variations are within the scope of the present disclosure.

[0076] In addition, the present disclosure also provides a laser radar, which includes the transmitter described above.

[0077] Example

[0078] Figure 7 A schematic diagram of the configuration of a transmitter 700 for a lidar according to an example of the present disclosure is shown.

[0079] The operating band of the transmitter 700 in this example is at 905nm, that is, the laser beam with a central wavelength of 905nm is emitted. The requirements for beam collimation in this example are as follows: effective aperture 6mm, focal length 10mm, field of view angle (FOV) = 60 degrees, and the spot of parallel light incident on the focal plane is less than 100μm as the acceptable standard for aberration. The far-field structure is a point cloud or a multi-line combination.

[0080] Accordingly, the diagonal length of the laser surface light source 701 is 11.5 mm, and the distance between the laser surface light source 701 and the first super lens 702 is 7.3 mm. The diameter of the first super lens 702 is 17 mm, and the diameter of the second super lens 703 is 7 mm. Those skilled in the art should recognize that the "caliber" and "diameter" of the lens mentioned herein are two different concepts. Specifically, the "caliber" herein refers to the entrance pupil diameter of the lens, while the "diameter" refers to the geometric diameter of the lens.

[0081] Fig. 8A The figure shows the relationship between the focal plane spot size and the field of view angle when the point cloud phase is not considered. Fig. 8A As shown, the maximum spot size is 33 μm, which is smaller than the design requirement of 100 μm.

[0082] Figure 8B Shown with Fig. 8A The corresponding modulation transfer function curve.

[0083] also, Fig. 9A shows a phase diagram of a first metalens 702 according to an example of the present disclosure, Fig. 9B shows a phase diagram of a second metalens 703 according to an example of the present disclosure, and Fig. 9C A simulation diagram of a point cloud of 256 points projected at the far field is shown according to an example of the present disclosure.

[0084] Fig.10 A graph showing the relationship between the transmittance and phase of the nano-pillars according to an example of the present disclosure at an operating band of 905 nm and the side length of the nano-pillars.

[0085] according to Fig. 9A and Fig. 9B The phases of the first superlens 702 and the second superlens 703 shown in FIG. Fig.10 The data of the nanostructure in the superlens under the working band of 905nm shown can be used to set the corresponding nanostructure according to the phase at different positions, so as to obtain the entire processing layout of the first superlens 702 and the second superlens 703, wherein the microstructure units of the first superlens 702 and the second superlens 703 have a square period, a side length of 450nm, and the substrate material is quartz glass. The material of the nanostructure is amorphous silicon, the nanostructure is a nano-square column with a side length ranging from 100nm to 350nm and a column height of 600nm, the filling material between the nano-square columns is silane, covering the phase from 0 to 2π, and the average transmittance is greater than 95.6%.

[0086] According to the transmitter for laser radar and the laser radar including the transmitter disclosed in the present invention, a metalens can be used to simultaneously realize the function of generating far-field point cloud or multi-line and the function of beam collimation, thereby reducing the number of lenses in the transmitter, thereby reducing the overall volume, weight and cost of the laser radar. In addition, according to the transmitter for laser radar and the laser radar including the transmitter disclosed in the present invention, a non-mechanical scanning transmitter can be realized using a laser surface light source composed of a laser source array, thereby reducing the complexity of the transmitter while increasing the overall service life of the laser radar.

[0087] Although the present disclosure has been described with reference to exemplary embodiments thereof, it will be apparent to those skilled in the art that various modifications and variations may be made without departing from the spirit and scope of the present disclosure as set forth in the claims.

Claims

1. A transmitter for laser radar, comprising: A laser surface light source emits an initial light beam with an initial divergence angle; The laser surface light source comprises a plurality of laser source arrays, each of which is composed of a plurality of laser sources; a first super lens, wherein the initial light beam passes through the first super lens, so that the initial light beam having the initial divergence angle is transformed into a first light beam having a first divergence angle; a second super lens, wherein the second super lens has the function of collimating the light beam and generating a point cloud or multi-line in the far field; the first light beam passes through the second super lens, so that the first light beam with the first divergence angle is transformed into a second light beam with a second divergence angle, and the second light beam is used to generate a point cloud or multi-line in the far field, The first super lens is located between the second super lens and the laser surface light source, and the aperture of the second super lens is smaller than the aperture of the first super lens, and The first divergence angle is smaller than the initial divergence angle, and the second divergence angle is smaller than the first divergence angle.

2. The transmitter according to claim 1, wherein: A ratio between the first divergence angle and the initial divergence angle is less than 1 / 5.

3. The transmitter according to claim 1, wherein: The second divergence angle is determined by the farthest working distance of the laser radar and the minimum size of a target detectable at the farthest working distance.

4. The transmitter according to claim 1, wherein: The plurality of laser light source arrays are lit up in sequence according to a predetermined order.

5. The transmitter according to claim 1, wherein: The plurality of laser light source arrays are randomly lit.

6. The transmitter according to claim 4 or 5, wherein: Among the plurality of laser light source arrays, the number of times the laser light source array corresponding to the central field of view is turned on is greater than the number of times the laser light source array corresponding to the outside of the central field of view is turned on.

7. The transmitter according to claim 1, wherein: Each of the first superlens and the second superlens includes a substrate and a microstructure layer disposed on the substrate, and Wherein, the microstructure layer includes microstructure units arranged in an array.

8. The transmitter according to claim 7, wherein: The size and shape of the microstructure unit are determined according to the working band of the laser radar.

9. The transmitter according to claim 1, wherein: The point cloud or multi-lines are generated in the far field by adjusting the phase of the initial beam.

10. A laser radar comprising a transmitter according to any one of claims 1 to 9.

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