Light emitting device, light detection device, and lidar

Abstract

The invention provides a light emitting device, a light detection device and a laser radar. The light emitting device comprises a laser array comprising a plurality of lasers, the plurality of lasers are arranged in a linear array or an area array, the lasers in the laser array are configured to output emission signals, and the emission signals are transmitted along an emission light path; the first optical assembly is arranged on the emission light path and configured with an equivalent focal length larger than a first preset value, the first optical assembly comprises a first main lens group unit and a first micro lens group unit, and the first preset value is the focal length of the first main lens group unit; wherein the equivalent focal length of the first optical assembly is M times, Mgt, of the focal length of the first main lens group unit; 1; the first micro lens group unit is arranged between the laser array and the first main lens group unit. The power density in the point cloud field angle area is improved through the arrangement of the first optical assembly of the light emitting device, and the background light noise power in the point cloud field angle area is reduced based on the arrangement of the second optical assembly of the light detection device, so that the distance measurement capability of the radar is improved.

Description

Technical Field

[0001] This application relates to the technical field of optical ranging, and in particular to an optical emission device, an optical detection device, and a lidar. Background Art

[0002] A lidar is a detection device that calculates the distance to an object by emitting a laser and detecting the echo signal reflected after the laser reaches the surface of the object. Therefore, a lidar needs to include two parts: an optical emission (Transmitter X) element and an optical detection (Receiver X) element, which can be referred to as an optical emission module and an optical detection module.

[0003] The lidar includes an optical system, which is distributed in the optical emission module and the optical detection module. For example, the optical emission module includes a main lens group for collimating the emission signal of the laser, etc., and the optical detection module includes a receiving lens for converging the echo signal towards the detector, etc. For the optical emission module (or the optical detection module), its field of view (FOV) is positively correlated with the longitudinal dimension of the light-emitting surface (or the photosensitive surface) of the optical emission module, and negatively correlated with the equivalent focal length of the transmitting and / or receiving lens (group). Among them, the longitudinal dimension of the light-emitting surface (or the photosensitive surface) is positively correlated with the height of the entire lidar.

[0004] The height dimension of the lidar product is an important parameter that customers are concerned about. In order to enable the entire lidar to maintain an appropriate height while covering a large field of view (such as 105°), it is necessary to reduce the focal length of the emission module and / or the detection module, such as replacing optical devices with shorter focal lengths, etc. This will not only reduce the duty cycle of the light-emitting surface but also limit the vertical resolution in the longitudinal direction. Summary of the Invention

[0005] In view of the above-mentioned disadvantages of the prior art, this application provides an optical emission device, an optical detection device, and a lidar, which solve the problems caused by the mutual restriction between the focal length and the height of the above-mentioned lidar, and can improve the ranging ability of the lidar without increasing the height of the radar.

[0006] To achieve the above object and other related objects, a first aspect of the present application provides an optical emission device for a lidar. The optical emission device includes: a laser array including a plurality of lasers arranged in a linear array or a planar array. The lasers in the laser array are configured to output emission signals, and the emission signals are transmitted along an emission optical path; a first optical component disposed on the emission optical path and configured with an equivalent focal length greater than a first preset value. Wherein, the first optical component includes a first main lens group unit and a first microlens group unit, and the first preset value is the focal length of the first main lens group unit; wherein, the equivalent focal length of the first optical component is M times the focal length of the first main lens group unit, M>1; the first microlens group unit is disposed between the laser array and the first main lens group unit.

[0007] Optionally, the first microlens group unit includes: a concave lens array including a plurality of concave lenses, and one of the concave lenses is provided corresponding to one laser.

[0008] Optionally, the vertical pitch between adjacent concave lenses in the concave lens array is not less than the height of the light-emitting surface of one laser in the laser array.

[0009] Optionally, the vertical pitch between adjacent concave lenses in the concave lens array is the same as the center spacing between adjacent lasers in the laser array.

[0010] Optionally, the first microlens group unit includes a microlens array.

[0011] Optionally, the light-emitting surface of the lasers in the laser array includes a plurality of light-emitting points, and one microlens in the microlens array is provided corresponding to one light-emitting point.

[0012] Optionally, the pitch between adjacent microlenses in the microlens array is the same as the pitch between adjacent light-emitting points among the plurality of light-emitting points.

[0013] Optionally, the laser array includes N columns of lasers arranged in a staggered manner, where N>M.

[0014] In a second aspect, a light detection device for a lidar is provided. The light detection device includes: a photodetector array including a plurality of photodetectors arranged in a linear array or a planar array. The photodetectors in the photodetector array are configured to detect, from a reception optical path, an echo signal reflected after the emission signal reaches an object; a second optical component disposed on the reception optical path and configured with an equivalent focal length greater than a second preset value; wherein, the second optical component includes a second main lens group unit and a second microlens group unit at the reception end, and the second preset value is the focal length of the second main lens group unit; wherein, the equivalent focal length of the second optical component is P times the focal length of the second main lens group unit, P>1, and the second microlens group unit is disposed between the photodetector array and the second main lens group unit.

[0015] Optionally, the second microlens group unit includes: a concave lens array including a plurality of concave lenses, where one concave lens corresponds to one photodetector. Optionally, the vertical pitch between adjacent concave lenses in the concave lens array is greater than the height of the receiving surface of one photodetector in the photodetector array. Optionally, the pitch between longitudinally adjacent concave lenses in the concave lens array is equal to the center pitch between adjacent photodetectors in one column of the photodetector array. Optionally, the photodetector array includes Q columns of photodetectors arranged in a staggered manner, where Q > P.

[0016] In a third aspect, a lidar is provided, including: an optical emission device provided as in the first aspect; and an optical detection device provided as in the second aspect.

[0017] In the embodiments of the present application, by setting the first optical component of the optical emission device, the power density within the point cloud field of view angle area is increased. By setting the second optical component of the optical detection device, the background light noise power within the point cloud field of view angle area is reduced, thereby improving the ranging ability of the lidar. Description of the Drawings

[0018] Figure 1A Schematic diagram showing the relationship between the field of view and focal length of the optical emission module of the optical detection system in an example.

[0019] Figure 1B Schematic diagram showing the relationship between the field of view and focal length of the optical detection module of the optical detection system in an example.

[0020] Figure 1C Schematic diagram showing the channel correspondence relationship between the transmitting end and receiving end of a horizontal scanning mechanical lidar in an example.

[0021] Figure 2A Schematic diagram showing the light emitting surface of a laser in an example.

[0022] Figure 2B Show Figure 2A Simplified representation schematic diagram of

[0023] Figure 3 Schematic diagram for explaining the principle of the vertical resolution of the optical emission module in an example.

[0024] Figure 4 Schematic diagram showing the light emission and reception optical path of the lidar in an embodiment of the present application.

[0025] Figure 5A Schematic diagram showing the structure of the optical emission module in an embodiment of the present application.

[0026] Figure 5B Schematic diagram showing the structure of the optical emission module in another embodiment of the present application.

[0027] Figure 6 It shows a front view structural schematic diagram of a magnified light-emitting surface formed at different focal lengths in an embodiment of the present application.

[0028] Figure 7 It shows a structural schematic diagram of the light detection module of a lidar in an embodiment of the present application.

[0029] Figure 8 It shows a schematic principle diagram for determining the value of M according to the specific structural parameters of the light emission module in an embodiment of the present application.

[0030] Figure 9 It shows a front view structural schematic diagram of the layout and the matching concave lens array of a magnified light-emitting surface formed at different focal lengths in an embodiment of the present application.

[0031] Figure 10A It shows a structural schematic diagram of a lidar with a paraxial optical path structure in an embodiment of the present application.

[0032] Figure 10B It shows a front view structural schematic diagram of the laser array and the photodetector array of a lidar with a paraxial optical path structure in an embodiment of the present application.

[0033] Figure 10C Show Figure 10B A curve schematic diagram of the ranging ability simulation result of the lidar in

[0034] Figure 11A It shows a structural schematic diagram of a lidar with a coaxial optical path structure in an embodiment of the present application.

[0035] Figure 11B It shows a structural schematic diagram of a lidar with a coaxial optical path structure in another embodiment of the present application.

[0036] Figure 12A It shows an optical path schematic diagram of the transmitting end without a sleeve in an embodiment of the present application.

[0037] Figure 12B It shows an optical path schematic diagram of the transmitting end with a sleeve in an embodiment of the present application.

[0038] Figure 12C It shows an optical path schematic diagram of the receiving end with a sleeve in an embodiment of the present application. Detailed implementation manners

[0039] The following describes the embodiments of the present application through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and application systems without departing from the spirit of the present application. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0040] The following takes the drawings as a reference and details the embodiments of the present application so that those skilled in the art to which the present application pertains can easily implement it. The present application can be embodied in many different forms and is not limited to the embodiments described herein.

[0041] To clearly illustrate the present application, devices irrelevant to the description are omitted, and the same or similar components throughout the specification are given the same reference numerals.

[0042] Throughout the specification, when it is said that a device is "connected" to another device, this includes not only the case of "direct connection" but also the case of "indirect connection" with other elements placed in between. Additionally, when it is said that a certain device "includes" a certain component, unless there is a particularly contrary record, it does not exclude other components but means that other components can also be included.

[0043] When it is said that a device is "above" another device, this can be directly above the other device, but there can also be other devices in between. When it is said that a device is "directly" "above" another device, there are no other devices in between.

[0044] Although in some instances the terms first, second, etc. are used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, descriptions such as a first interface and a second interface. Furthermore, as used herein, the singular forms "a", "an", and "the" are intended to also include the plural forms unless the context indicates otherwise. It should be further understood that the terms "comprising", "including" indicate the presence of the stated features, steps, operations, elements, components, items, kinds, and / or groups, but do not preclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups. The terms "or" and "and / or" used herein are to be construed as inclusive, or meaning any one or any combination. Thus, "A, B, or C" or "A, B, and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B, and C". An exception to this definition occurs only when the combination of elements, functions, steps, or operations is inherently mutually exclusive in some way.

[0045] The technical terms used herein are only for referring to specific embodiments and are not intended to limit this application. The singular forms used herein also include the plural forms as long as the statements do not clearly indicate the contrary meaning. The meaning of "including" used in the specification is to embody specific characteristics, regions, integers, steps, operations, elements, and / or components, and does not exclude the existence or addition of other characteristics, regions, integers, steps, operations, elements, and / or components.

[0046] Relative spatial terms such as "lower", "upper", etc. may be used to more easily describe the relationship of one device relative to another device illustrated in the drawings. Such terms refer to not only the meaning indicated in the drawings but also other meanings or operations of the devices in use. For example, if the device in the drawing is flipped, a device that was described as "lower" than another device is then described as "upper" than another device. Therefore, the exemplary term "lower" includes both upper and lower. The device may be rotated 90° or other angles, and the relative spatial terms are interpreted accordingly.

[0047] Although not defined differently, including the technical terms and scientific terms used herein, all terms have the same meaning as generally understood by those skilled in the technical field to which this application belongs. Terms defined in commonly used dictionaries are additionally interpreted to have a meaning consistent with the relevant technical literature and the content presented currently, and should not be over-interpreted as ideal or overly formulaic meanings as long as they are not defined.

[0048] LiDAR is a device for ranging based on an optical detection system. Currently, application scenarios of LiDAR (such as autonomous driving) have requirements for high precision and large field of view. At the same time, in the actual scenario, it is necessary to minimize the size of the LiDAR as much as possible, especially the height of the LiDAR, which is one of the parameters that customers are most concerned about. However, there is a contradiction between a large field of view and a low height, which affects the performance of the LiDAR. The following illustrates the principle by way of example.

[0049] Please refer to Figure 1A and Figure 1B , which shows a schematic diagram of the relationship between the field of view and the focal length in an optical detection system in an example. Figure 1A A schematic diagram showing the relationship between the field of view and the focal length of the light emission module in the optical detection system. Figure 1B A schematic diagram showing the relationship between the field of view and the focal length of the light detection module in the optical detection system.

[0050] According to Figure 1A or Figure 1B the triangle corresponding to the field of view FOV shown in the figure, it can be calculated that:

[0051]

[0052] where a is the height (or longitudinal dimension) of the light emitting surface of a single laser 101A or the photosensitive surface of a single photodetector 101B, and f is the focal length of the lenses 102A and 102B (both are schematically represented as f in the figure, but it does not mean that the focal lengths of the two optical paths are the same. It is just to avoid too many numbers causing confusion). For LiDAR, the field of view of a single laser / single detector satisfies formula (1). At the same time, in the ideal case (when multiple lasers / detectors can be seamlessly connected longitudinally), whether it is a single light emitting surface 101A / single photosensitive surface 101B, or the height of all multiple lasers / detectors longitudinally, they all satisfy formula (1), and the field of view size is positively correlated with the height of the LiDAR.

[0053] Therefore, it can be inferred from formula (1) that the size of the light emitting surface of the light emission module and the photosensitive surface of the detection module of the LiDAR is positively correlated with the size of the LiDAR. Especially the height dimension of the LiDAR, compared with the width and depth, is a parameter that is more emphasized. Appropriate height is usually required in various application scenarios to adapt to the limited installation space.

[0054] Moreover, as can be seen from Equation (1), the size of the field of view (FOV) is positively correlated with the sizes of the light-emitting surface and the photosensitive surface, and negatively correlated with the equivalent focal length f of the optical components (such as the main lens group) in the light-emitting module and the light-detecting module. It can be seen that if a large FOV is to be maintained, either a should be increased or f should be decreased. However, increasing a may lead to an increase in the height of the lidar. Therefore, generally f is decreased to achieve the goal. However, this will cause problems that affect the performance of the lidar.

[0055] In addition, for a radar system, there is a certain correspondence between transmission and reception. The transmitting and receiving optical paths can be different, and the focal plane layouts of transmission and reception may also be different. However, ultimately, it is desired that the light emitted falls on a certain area of the target, and the reflected light energy from this area can exactly return to the detector, that is, the transmission and reception can be matched, and the transmission and reception channels can correspond to each other. To avoid confusion, some terms are defined below first.

[0056] Number of scan lines: That is, the number of channels for laser transmission and reception, or the number of the smallest addressable channels. Generally, the laser and the detector are configured in a 1:1 ratio. The number of scan lines is equal to the number of lasers or detectors, and also equal to the number of transmission channels or reception channels. At the same time, there are also cases where multiple detectors share one laser, or vice versa, or even there may be interleaved situations. In this case, the number of the smallest addressable channels needs to be specifically distinguished.

[0057] Divergence angle area: It refers to the angular area projected by the light-emitting area of the laser in a certain channel onto the far field through the optical system.

[0058] Receiving angle area: It refers to the angular area projected by the photosensitive surface of the detector in a certain channel onto the far field through the optical system.

[0059] Point cloud field of view angle area: It refers to the overlapping part of the divergence angle and the receiving angle. This is the real range covered by the point cloud, and it is the superposition of the echo signals reflected by all targets within this range. In different optical path designs, the point cloud field of view angle area shows different relative relationships with the divergence angle area and the receiving angle area. For example, the point cloud field of view angle area can be equal to the divergence angle area and less than the receiving angle area, for example, it can be equal to the receiving angle area and less than the divergence angle area, or for example, it can be equal to the overlapping part of the two. In the most ideal case, the point cloud field of view angle area is consistent with both the divergence angle and the receiving angle area.

[0060] The field of view (FOV) often includes the horizontal field of view (HFOV) and the vertical field of view (VFOV), which refers to the total angular range detected by all transmission and reception channels.

[0061] Reference Figure 1C As shown in the figure, on the left is the transmitting end (TX, transmitter), and multiple lasers (referring to the smallest addressable light-emitting units) are set at the transmitting end.

[0062] On the right is the receiver (RX), and multiple detectors (which also refer to the smallest addressable units) are provided at the receiver.

[0063] In the middle is the point cloud field of view angle. The horizontal position of each point represents the horizontal angle, and the horizontal angle θ shifts as the radar rotor rotates. The vertical position represents the pitch angle γ = β.

[0064] Furthermore, see Figure 2A and Figure 2B As shown, it is a schematic diagram of the light emitting surface of a laser in an example. The laser is exemplarily a Vertical Cavity Surface Emitting Laser (VCSEL) 200. Figure 2A It is a top view schematic diagram of a more practical VCSEL. Figure 2B Based on Figure 2A An abstract and simplified schematic diagram. The duty cycle of light emission refers to the ratio of the area covered by the light emitting surface to the total area, which can be the ratio of the sum of the areas of each light emitting point 201 in the figure to the area of the dashed square 202 or the entire top surface area of the VCSEL, etc. All in all, the duty cycle of light emission is limited by OA / PITCH. Among them, OA is the area of one light emitting point 201, and PITCH is the pitch in the longitudinal direction between adjacent light emitting points 201 (i.e., the distance between the centers of adjacent light emitting points, as marked by the double-headed arrow in the figure). It can be seen that when OA is larger or the pitch is smaller, the duty cycle is higher. It should be noted that this is only an example. In this application, no limitation is imposed on the type of the laser. For example, the laser can be an Edge Emitting Laser (EEL), a VCSEL, or a Photonic Crystal Surface Emitting Semiconductor Lasers (PCSEL). Similarly, in this application, no limitation is imposed on the type of the detector. For example, the optical detector can be an APD, a single photon avalanche diode array SPAD(s), or a silicon photomultiplier SiPM.

[0065] Furthermore, as Figure 3 shown, when the light emission module uses, for example, a laser array as the laser array, the vertical angle resolution of the lidar is determined according to the ratio d / f between the center distance d of adjacent lasers 301 and 302 arranged longitudinally (or column-wise) and the equivalent focal length f of the main lens group (here only a convex lens 303 is shown as an equivalent situation in the embodiment, and the actual main lens group may include multiple lens groups, which is not limited here), that is, it is positively correlated with d and negatively correlated with f.

[0066] Based on the above, there is still room for improvement in the optical path system of existing lidars. On the one hand, in order to cover a large field of view (such as 105°) and maintain the height without increase, the focal length has to be minimized as much as possible. On the other hand, the duty cycle of the light-emitting surface of the laser is limited by the light-emitting point area / light-emitting point pitch, resulting in a low duty cycle. On the other hand, the vertical resolution is limited by d / f.

[0067] In view of the above, in the embodiments of the present application, a lidar is provided. Through an optical improvement method, an equivalent focal length longer than the physical size is achieved with a relatively short physical size, thereby increasing the power density within the point cloud field of view angle area, and / or reducing the background light noise power within the point cloud field of view angle area, so as to improve the ranging ability of the lidar.

[0068] Figure 4 A schematic diagram of the light-emitting and receiving optical path of a lidar is shown. The lidar may specifically include:

[0069] A light emission module, namely a laser array arranged in a linear array or a planar array, is correspondingly arranged with a first optical component. For example, it can be arranged on the focal plane of the first optical component and is adapted to emit a transmission signal, and the transmission signal is transmitted along the transmission optical path. The first optical component may form an equivalent focal length greater than a first preset value.

[0070] A light detection module, namely a light detector array arranged in a linear array or a planar array, is correspondingly arranged with a second optical component. For example, it can be arranged on the focal plane of the second optical component and is adapted to detect the echo signal reflected after the transmission signal reaches an object. The second optical component may form an equivalent focal length greater than a second preset value. Thus, by setting the optical components at the transmitting end and / or the receiving end of the lidar, an elongated focal length on the receiving / transmitting side is achieved. Without changing the overall height of the lidar, the power density within the point cloud field of view angle area can be increased, and / or the background light noise power within the point cloud field of view angle area can be reduced, greatly improving the ranging ability of the lidar.

[0071] The following will introduce in more detail from each single side of the transmitting TX end and the receiving RX end respectively.

[0072] As Figure 5A shown, a schematic diagram of the structure of the light emission module in an embodiment of the present application is presented.

[0073] The light emission module includes: a laser array 501 and a first optical component.

[0074] The laser array 501 includes a plurality of lasers 511. The plurality of lasers 511 may be arranged in a linear array or a planar array form. Each laser 511 is configured to output an emission signal, that is, emit laser light. Exemplarily, the laser 511 may be implemented, for example, as a vertical cavity surface emitting laser (VSCEL) or an edge emitting laser (EEL).

[0075] The first optical component is disposed on the emission optical path and is configured with an equivalent focal length greater than a first preset value. Specifically, as Figure 5A shown in the example, the first optical component includes: a main lens group unit, which may specifically be the main lens group originally used in the light emission module to collimate the emission signal, and is Figure 5A exemplarily shown as an equivalent convex lens 502 in the figure; and a first divergence unit for diverging the emission signal, and in Figure 5A the figure, the first divergence unit is exemplarily presented as a concave lens array 503. Among them, each concave lens 531 in the concave lens array 503 is provided corresponding to a laser 511 (a single addressable and controllable unit that can be turned on or off) to lengthen (compared with the focal length formed by the emission optical path with only the main lens group) the focal length of the emission optical path, so as to realize the improvement of the light emitting surface of the laser 511 corresponding to the single pixel (compared with the size of the laser in the scheme of setting the laser on the focal plane A of the main lens group unit, but actually in the scheme with a longer focal length in the present application, the laser is only set at the focal plane B, not A). In terms of the point cloud level, it is to increase the power density within the point cloud field of view angle area, that is, the energy of the emission end used to form one point in the point cloud is greater. Among them, the pixel refers to a pixel point or point cloud in the point cloud map formed by the corresponding lidar. For example, the light emitting surface of each laser / the photosensitive surface of each light detector can correspond to a pixel point, and then the transceiver unit together constitutes a channel, and then also corresponds to the wire harness mentioned above. The pitch between two adjacent concave lenses 531 in the concave lens array 503 may be the same as the center distance between adjacent lasers 511.

[0076] It should be noted that the main lens group unit is exemplarily represented by a convex lens 502 in the figure. Actually, this convex lens 502 is only one representation of the main lens group unit. The main lens group unit may be the main lens group in the light emission module, which may include multiple lenses (for example Figure 4 shown), so it is not limited by the simplified representation of the convex lens 502 in the figure; in addition, the equivalent lens of the main lens group unit may also be other forms of convex lenses, such as plano-convex lenses, etc., which are not limited here. The main lens group unit may have a first focal length, which is represented in the figure as the distance f" from the main plane C of the convex lens 502 to its first focal point (the corresponding focal plane is A).

[0077] In some embodiments, the concave lens array 503 is disposed between the laser array 501 and the main lens group unit, and each concave lens 531 in the concave lens array 503 is arranged corresponding to a laser 511.

[0078] The concave lens array 503 is adapted to diverge the emitted signal and then converge it through the main lens group unit, so as to form an equivalent focal length of the first optical component that is longer than a first preset value. Specifically, f" is the focal length of the main lens group (i.e., Figure 5A the main lens group unit of, which is representatively replaced by one convex lens, but generally it will be a main lens group. In Figure 5A ), the main lens group unit = the main lens group = the positive lens = the convex lens = the leftmost lens), f is the equivalent focal length of the combination of the two lenses (i.e., the convex lens 502 + the concave lens array 503) in the figure, and L is the physical entity size. Among them, the principal plane after the combination of the positive and negative lens groups (i.e., the convex lens 502 + the concave lens array 503) will move forward. As shown in the figure, the left endpoint of f has moved leftward compared to the left endpoint of f", that is, the principal plane D located at the left endpoint of f has moved leftward compared to the principal plane C of the main lens group unit, and the entire focal plane will move backward, for example, from A to B. When calculating the focal length, the position of the principal plane D can be determined according to the backward extension line of the converging light rays, and its backward extension line can be seen Figure 5A as the dashed lines E1 and E2 in. This is also an advantage of this optical path: L < f, which realizes a longer equivalent focal length f with a relatively short physical size L.

[0079] It can be understood from the above that for the optical emission module (i.e., the TX end), on the basis of the optical path of the original main lens group of the lidar (i.e., the main lens group unit / convex lens 502 in the figure), an additional concave lens array 503 is added in the embodiment of the present application to be combined with it to lengthen the focal length, that is, the focal length is lengthened from the focal length f" of the main lens group to the equivalent focal length f of the combination of the two lenses (i.e., the convex lens 502 + the concave lens 530 in the concave lens array 503). Let M be the focal length magnification factor, M = f / f". Optionally, the distance between the first diffusion unit and the principal plane of the main lens group unit can be less than f".

[0080] According to Equation (1), when the FOV remains unchanged and the focal length f is equivalently increased, a will equivalently increase accordingly, that is, the light emitting surface of each pixel will be equivalently increased. Furthermore, the light emitting energy of a single pixel (corresponding to a point in the point cloud map of the lidar) can be improved, and the power density within the point cloud field of view angle area is increased accordingly (i.e., the more light emitting points 201 are included in the same area), and the ranging ability is also increased proportionally. For example, the ranging ability can be increased from 200m to 300m, etc.

[0081] It should be noted that for a VSCEL laser, its viewing angle is relatively large, which may cause the emitted light rays F1 and F2 to deviate from the concave lens 530. The light rays that do not pass through the concave lens 530 will be defocused, and after being sent out by the main lens group unit with a large divergence angle, the echo signal formed is very likely to be received by the photodetectors of other channels, thus forming crosstalk; or, signal loss occurs due to deviation from the main lens group unit. Therefore, in some embodiments, the viewing angle of the laser array can be compressed.

[0082] As Figure 5B shown, it shows a schematic structural diagram of an optical emission module in another embodiment of the present application.

[0083] Figure 5B The laser array 501 and the first optical component of another embodiment are shown.

[0084] In this embodiment, the first optical component includes a main lens group unit and a microlens group unit 503.

[0085] It should be noted that Figure 5B the main lens group unit is still equivalently represented by the convex lens 502. The main lens group unit may have a first focal length, which is represented in the figure as the distance f" from its principal plane C to its first focal point (the corresponding focal plane is A).

[0086] In this embodiment, the microlens group unit 504 includes, in addition to the concave lens array 503, a microlens array 505. In Figure 5B the microlens array 551 is disposed between the laser array 501 and the concave lens array 503. Among them, since each light-emitting surface of each laser 511 (such as a VCSEL) has a plurality of light-emitting points, a plurality of microlenses 551 (specifically, microlenses) in the microlens array 551 are each disposed corresponding to one light-emitting point to converge the light emitted from the light-emitting point and transmit it to the corresponding concave lens 531. That is to say, through the microlens array 551, the divergence angle of the light emitted from each light-emitting point can be compressed, and thus the divergence angle of the emission signal output by the laser 511 and the laser array 501 can be suppressed, thereby avoiding Figure 5A the situation where the light rays F1 and F2 deviate from the concave lens array 503 in

[0087] Specifically, explain the principle in this embodiment. Different from Figure 5A the Figure 5B embodiment, in the Figure 5B embodiment, the equivalent focal length achieved by the combination of 3 lenses (i.e., the convex lens 502 + the concave lens 530 in the concave lens array 503 + the microlens 551 in the microlens array 505) extends the focal length. Figure 5BThe main lens group unit is representatively shown by one convex lens, but generally it is a main lens group. In Figure 5B In Figure 5B , the focal length of the main lens group unit = the main lens group = the positive lens = the convex lens = the leftmost lens) is \(f'\), \(f\) is the equivalent focal length of the combination of the three lenses in the figure (i.e., the convex lens 502 + the concave lens 530 in the concave lens array 503 + the microlens 551 in the microlens array 505), and \(L\) is the physical entity size. Among them, the principal plane after the combination of the positive and negative lens groups (i.e., the convex lens 502 + the concave lens 530 in the concave lens array 503) will move forward. As shown in the figure, the left endpoint of \(f\) moves leftward compared to the left endpoint of \(f''\), that is, the principal plane \(D\) of the left endpoint of \(f\) moves leftward compared to the principal plane \(C\) of the main lens group unit, and the entire focal plane will move backward, for example, from \(A\) to \(B\). When calculating the focal length, according to the reverse extension line of the converging light, the position of the principal plane is determined, and the reverse extension lines can be seen as the dotted lines \(S1\) and \(S2\) in

[0088] For the TX end, on the basis of the optical path of the original main lens group unit (i.e., the main lens group), in the embodiment of the present application, a concave lens array 503 is used to lengthen the focal length, and a microlens array 505 is used to compress and limit the divergence angle of the laser 501, and the focal length is lengthened from the focal length \(f''\) of the main lens group unit to the equivalent focal length \(f\). Let \(M\) be the focal length magnification factor, \(M = f / f''\). According to Equation (1), when the FOV remains unchanged, as the focal length \(f\) increases, \(a\) correspondingly increases, that is, the light-emitting surface is enlarged. Furthermore, the luminous energy of a single pixel (corresponding to a point in the point cloud map of the lidar) can be increased, and the power density within the point cloud field of view angle area is correspondingly increased, and the ranging ability is also increased proportionally.

[0089] Exemplarily, the pitch between two adjacent microlenses in the microlens array 504 is the same as the pitch of the light-emitting points. It should be noted that the three concave lenses corresponding to the three lasers 511 shown in the figure, and the three microlenses corresponding to each laser 511 are all schematic quantities, rather than limiting their specific implementations.

[0090] In Figure 5A and Figure 5B In the example, the light-emitting surface \(B\) of the laser array 501 (including the light-emitting surface of each laser) is located on the focal plane of the equivalent lens of the first optical component, so as to maintain a distance of the equivalent focal length \(f\) from the principal plane \(D\) of the equivalent lens.

[0091] To more intuitively see the enlargement of the light-emitting surface, reference can be made to Figure 6 as shown.

[0092] In Figure 6In [the figure], it shows a front view structural schematic diagram of forming an enlarged light-emitting surface at different focal lengths in an embodiment of the present application. Figure 6 In [the figure], from left to right, it successively shows the size comparison of the light-emitting surfaces in the cases where M is less than but approximately equal to 1 (i.e., the light-emitting surface is not enlarged, or the optical path without using a concave lens, such as the optical path only including the main lens group unit), M is less than but approximately equal to 2, and M is less than but approximately equal to 4; among them, it shows the equivalent magnification of the light-emitting areas of 8 light-emitting surfaces 11, 12, 13, 14, 21, 22, 23, and 24 in the three cases. It can be combined with Figure 5A or Figure 5B and Figure 6 for understanding. Figure 5A , Figure 5B In [the figure], the 3 lasers arranged longitudinally in the side view perspective can be in 1 column, for example, corresponding to Figure 6 the column of light-emitting surfaces 11, 12, and 13 corresponding to M less than but approximately equal to 2 in [the figure]. Each laser is correspondingly provided with one of the micro-concave lenses Y in a concave lens array. For intuitive illustration, only one concave lens is drawn for one light-emitting surface 21 on the right side in Figure 6 [the figure], presented as a circle surrounding the light-emitting surface 21, but actually other lasers are also correspondingly provided with concave lenses, which are just omitted here. It should be noted that the diameter of the concave lens is larger than the diameter of the light-emitting surface to fully cover the light-emitting surface and receive more light rays of the emitted signal, but at the same time, the diameter of the concave lens needs to be limited to a suitable size considering the height of the lidar.

[0093] According to Figure 6 it can be known that with the change of M, according to the diameters of a single light-emitting surface in the three cases from a0 → a1 → a2, an M-fold magnification is obtained, and the light-emitting surface area from a0 → a1 → a2 obtains an M 2 -fold magnification. After the light-emitting surface corresponding to each laser becomes larger, the far-reaching ability of the laser increases. At the point cloud level, the power density within the point cloud field of view angle area can be improved, thereby improving the ranging ability of the lidar. In addition, although in the case where M is less than but approximately equal to 4, the light-emitting surfaces of the closest lasers are relatively close (such as the light-emitting surfaces 11 and 13), but when equivalent to the emission angle area a2" in the far field, it will be a2 / M, and there will be no problem of overlapping and being unable to be recognized as two light-emitting surfaces. It should be noted that when the equivalent focal length of the first optical component is M times the focal length of the main lens group unit, if the laser is set on the focal plane of the first optical component, the entire area of each laser is M 2 times the area of the laser if it is set on the focal plane of the main lens group unit. If the duty cycle of the laser remains unchanged, then the area of the light-emitting surface of each laser will be M 2 times the area of the light-emitting surface if it is set on the focal plane of the main lens.

[0094] Alternatively, as Figure 6 can be seen, by adjusting the layout of the light-emitting surface at different focal lengths and magnification factors M, the height dimension can be maintained. For example, from Figure 6 a comparison of the heights h0, h1, and h2 in the three cases, h2 is slightly greater than h1, h1 is slightly greater than h0, and their differences can be ignored in actual situations. That is to say, the lidar can have almost no change in height dimension. However, the light-emitting surface of each laser has been magnified by M 2 times. At the point cloud level, the power density within the field of view angle area of the point cloud can be increased by M 2 times, thereby improving the ranging ability of the lidar.

[0095] In another example, the focal length can be enlarged on one side of the light detection module through a similar optical component. For the detection end, while stretching the focal length and keeping the area of the receiving device unchanged, the receiving angle area can be reduced, thereby reducing the background light noise power within the field of view angle area of the point cloud, and thus improving the ranging ability of the lidar.

[0096] As Figure 7 shown, a schematic structural diagram of the light detection module of the lidar in the embodiment of the present application is presented. The light detection module includes a photodetector array 701, which contains a plurality of photodetectors 711 arranged in an array. The photodetectors 711 are configured to detect the reflected signal after the transmitted signal reaches an object for detection. Among them, a "channel" is formed between one or more photodetectors 711 and one or more lasers. For example, a channel is formed between one photodetector and one laser, and the echo signal of the transmitted signal of the laser is received by the photodetector 711 belonging to the same channel. Each channel corresponds to the detection of a certain field of view angle or a certain field of view angle range (receiving angle area). In a specific example, each of the photodetectors 711 can be implemented by, for example, SiPM (Silicon Photo Multiplier) or SPAD(s) (Single Photon Avalanche Diode).

[0097] Exemplarily, the light detection module may further include a second optical component provided corresponding to the photodetector array 701. The second optical component specifically includes a second focusing unit and a second diverging unit. In Figure 6Among them, the second converging unit can be an original lens or lens group for converging echo signals, which can be equivalently shown as the convex lens 702 on the far left in the figure, for converging echo signals and transmitting them to the photodetector array 701. The second diverging unit can be implemented as a concave lens array 703, where each concave lens 731 corresponds to a photodetector 711 respectively; correspondingly, the pitch between longitudinally adjacent concave lenses 731 can be equal to the pitch between the centers of adjacent photodetectors 711 in a column of the photodetector array 701.

[0098] The focal length of the convex lens 702 is f2", as schematically shown in the figure as the length between the principal plane G of the convex lens 702 and its focal plane H. Exemplarily, the distance between the principal plane G of the convex lens 702 and the concave lens array 703 can be within the focal length f2" of the equivalent lens.

[0099] Through the combination of the convex lens 702 + the concave lens array 703, the principal plane of the formed equivalent lens is I, which has moved forward to the left compared to G. It can be understood that, similar to the previous figure 5A, Figure 5B Based on the same principle, the position of the I plane can be determined by the reverse extension lines K1 and K2 in the figure. For intuitive clarity, it is simply shown in the figure in a simplified ("...") manner, and it should be understood with reference to the previous figures.

[0100] Thus, as shown in the figure, a focal length f2 that is extended compared to the focal length f2" of the convex lens 702 is formed, which is the distance from I to the focal plane J. Optionally, the photosensitive surface of the photodetector array 701 can be located on the focal plane J at the right end of f2 to obtain the focusing of the echo signal. The physical length from G to J is L2, and it can be seen that f2 exceeds the physical distance limit of L2.

[0101] Different from the extension of the focal length of the optical emission module (i.e., the TX side), for the receiving end of the lidar, on the premise of ensuring that as many real detection signals (echo signals reflected after the transmitted signal encounters an obstacle) as possible are received, it is necessary to reduce the received background light intensity as much as possible to improve the signal-to-noise ratio. The following formula gives the background light P on the receiving side B :

[0102]

[0103] where pb is the background radiation density; BW is the full width at half maximum of the filter (nm); ρ is the reflectivity of the target; tr is the optical efficiency of the receiving lens barrel; A is the effective aperture (m), Sr is the effective area of the detector, and f is the focal length.

[0104] As can be seen from the above formula, by extending the focal length of the optical detection module (i.e., the RX side), the background light noise power within the point cloud field of view angle area can be reduced, the signal-to-noise ratio can be increased, and furthermore, the ranging ability of the entire lidar can be improved while maintaining the height dimension of the lidar. Additionally, if the equivalent focal length of the second optical component is P times the focal length of the main lens group unit of the receiving end, where P > 1, the receiving angle area can be reduced by P 2 times. It should be noted that different letter symbols are used for the transmitting end and the receiving end. For example, M and P are respectively used to represent the magnification of the extended focal length of the optical component, just to illustrate that different magnification factors can be used on the transmitting and receiving sides. However, it can be understood that the same magnification factor can also be set on the transmitting and receiving sides. In some parts of the text, only the discussion of M is made, and P is similar, and no secondary elaboration is made in the application.

[0105] In addition to the optical transmission module and the optical detection module, a control module (not shown) is usually included in the lidar to control the optical transmission module to emit the transmission signal, control the optical detection module to detect the data of the echo signal, and can calculate the data to obtain the detection result.

[0106] According to the above embodiments or combinations of embodiments, various problems described previously can be solved. On the one hand, by obtaining a larger focal length for the optical paths of the optical transmission module and the optical detection module, it is realized that while the lidar's focal length is increased by M times, the total height of the focal plane is maintained, resulting in almost no change in the overall size of the lidar. On the other hand, for the transmitting module TX, the size of the light-emitting surface corresponding to a single pixel point can be increased, thereby increasing the power density; for the receiving module RX, the receiving angle area can be reduced, and thus the background light noise power within the point cloud field of view angle area can be reduced; furthermore, both are conducive to improving the ranging ability; and the increase in f makes d / f decrease, meaning that the angular difference between adjacent lasers in the vertical direction decreases, thereby improving the vertical angle resolution. On the other hand, Figure 5B setting a microlens array in front of the laser array to converge the transmission signal is also conducive to further improving the utilization efficiency of the emitted light.

[0107] In some embodiments, reference can be made to Figure 8 and Figure 9 to discuss the reasonable value of M.

[0108] Similar to Figure 5A and Figure 5B before, in Figure 8 , f" is the focal length of the convex lens 802 equivalent to the main lens group unit, f is the focal length of the first optical component, and L is the physical size. Through the combination of the convex lens 802 and the concave lens 803, the achieved equivalent focal length is f, and f = M * f". It should be noted that Figure 8Schematically drawn is the optical path after the emission signal of one light-emitting point of one laser 801 is compressed by a microlens 804 and then diffused by a corresponding concave lens 803. All the light-emitting points of the laser 801 are not drawn, nor are other lasers and their corresponding other concave lenses (representing concave lenses) drawn, but they can actually exist.

[0109] According to the markings shown in the figure, the calculation formula for M is as shown in Equation (2) below:

[0110] M = f / f" = Δy / Δy" ≈ a / β (2)

[0111] Where, Δy is the height of the laser (in the y direction) on the focal plane of the extended focal length, that is, the height of the light-emitting surface corresponding to this position, and Δy" is the height of the light-emitting surface equivalent to the focal plane of the convex lens 802. To maximize the magnification M as much as possible, the cone angle β = (laser divergence angle θ * OA / PITCH) needs to be as small as possible, and the F value (aperture value f is the focal length, D is the aperture diameter) should be designed to be smaller, that is, the main lens (i.e., the main lens group) with a larger aperture. Refer to Figure 8 , the cone angle of the main lens = α; the divergence angle of the laser 801 = θ; β is related to the light output quality of the laser 801 itself on the one hand and the compression effect of the microlens array on the other hand.

[0112] In addition, the upper limit of M can also be derived. After magnifying the focal length f, for the light-emitting surface of the same area (it can be understood that a remains unchanged), the divergence angle is reduced in proportion (common divergence angle θ = 2 × arctan(a / 2f)), and the angular resolution is improved. Therefore, it is allowed that the lasers in the laser array are arranged in multiple columns (N columns) in a staggered manner.

[0113] The number of staggered columns N should be limited. N may affect the width of the radar product. Although the width direction is not as important as the height direction, it cannot be unrestricted. Suppose there are N columns of lasers arranged in a staggered manner. Considering that all the light emitted by each laser can pass through the corresponding concave lenses (for example Figure 9 covered by the concave lens in ), the height of the light-emitting surface needs to be slightly less than the pitch of adjacent concave lenses. It should be noted that the specific dimension referred to by the height of the light emission is related to the shape of the laser. If the laser is circular, the height refers to the diameter of the entire laser; if the laser is rectangular, the height refers to the width or length of the laser.

[0114] Refer to Figure 9 to show the schematic diagram of the magnification of the light-emitting surface in another embodiment of the present application.

[0115] Figure 9From left to right, it shows schematic diagrams of 8 light-emitting surfaces in three cases where M is less than but approximately equal to 1, N = 1; M is less than but approximately equal to 2, N = 2; and M is less than but approximately equal to 4, N = 4. That is to say, the leftmost corresponds to M less than but approximately equal to 1, N = 1, presenting 8 light-emitting surfaces 11 to 24 without magnification and arranged in a single column; the middle corresponds to M less than but approximately equal to 2, N = 2, presenting 8 light-emitting surfaces all magnified by nearly 4 times and arranged in 2 columns; the rightmost corresponds to M less than but approximately equal to 4, N = 4, presenting 8 light-emitting surfaces all magnified by nearly 16 times and arranged in 4 columns.

[0116] The figure also exemplarily shows concave lenses provided for each laser. For example, the annular Z surrounding the light-emitting surface 11 in the figure. To avoid the emission signal of the laser from avoiding the concave lens, a constraint condition can be set that the concave lens needs to completely cover the light-emitting surface. If the height of the light-emitting surface before magnification is y0, the height of the light-emitting surface after magnification approximately 2 times is y1, and the height of the light-emitting surface after magnification approximately 4 times is y2, in order for the concave lens to cover the light-emitting surface, the pitch of adjacent concave lenses in the longitudinal direction, for example, y2, needs to be less than the height of Z (if Z is circular, the height is its diameter length).

[0117] Under the limitations described in the above embodiments, the following formula can be obtained:

[0118] The height of the magnified light-emitting surface = M * the height of the light-emitting surface before magnification < the pitch of the concave lens = the focal length of the main lens group unit (equivalent convex lens) * the vertical angular resolution * N;

[0119] Regarding: the height of the magnified light-emitting surface < the pitch of the concave lens; it can be intuitively seen that Figure 9 In, the edges of the light-emitting surfaces (11 to 24) magnified approximately 2 times and 4 times are schematically drawn as dotted lines, while the edges of the concave lenses are schematically drawn as solid lines. The dotted-line edges corresponding to each light-emitting surface all fall within the solid-line rings of the corresponding concave lenses. The figure schematically marks that the light-emitting surface 11 when magnified approximately 4 times falls into the concave lens Z.

[0120] Regarding: the height of the magnified light-emitting surface = M * the height of the light-emitting surface before magnification; referring to Figure 9 , if the light-emitting surface is magnified 2 times, the height of the magnified light-emitting surface is y1; if the light-emitting surface is magnified 4 times, the height of the magnified light-emitting surface is y2; the pixel height before magnification is y0, y2 = 2 * y1 = 4 * y0.

[0121] Regarding: the pitch of the concave lens = the focal length of the main lens group unit * the vertical angular resolution * N, referring to Figure 9 , the pitch of the concave lens is the distance between the centers of adjacent light-emitting surfaces. In the figure, the interval b is used as the dimension measurement unit, and the interval b is equal to the focal length of the main lens group unit * the vertical angular resolution. The pitch of the concave lens is equal to N times the interval b. As Figure 9As shown, when the light-emitting surface is magnified by two times, the pitch of the concave lens is 2b; when the light-emitting surface is magnified by four times, the pitch of the concave lens is 4b.

[0122] It is possible to obtain M * y0 < b * N by substituting the height of the light-emitting surface before magnification < the focal length of the main lens group unit * the vertical angular resolution * N into y0, f", and d / f. If the limitation of the process is not considered and adjacent light-emitting surfaces can be arranged adjacent to each other with almost no gap, then y0 ≈ b. Therefore, it can be obtained that M (magnification factor) < N (the number of stagger-arranged columns). In other words, the entire optical path cannot be magnified without limit, and the number of columns N that the lasers can be arranged in is the upper limit of the magnification factor M, that is, M < N.

[0123] As Figure 6 and Figure 9 show, in the three cases of M = N = 1, M = N = 2, and M = N = 4, under the limitation of M < N, the increase in the height direction after the arrangement of the light-emitting surfaces is extremely small and can be ignored compared to the size of the entire lidar, that is, h0 ≈ h1 ≈ h2. Thus, while improving the ranging ability of the lidar by extending the focal length of the emission module, there is no increase in the height direction.

[0124] It should be noted that the situation of the receiving end is similar. If the detector array is set as a Q-column detector arranged in a staggered pattern and the equivalent focal length of the second optical component is P times the focal length of the main lens group unit, then Q > P, which will not be elaborated here.

[0125] The applications and effects of the above solution will be illustrated below through embodiments of various lidars.

[0126] As Figure 10A shown, it is a schematic structural diagram of a lidar with a paraxial optical path structure in an embodiment of the present application. Figure 10B It is a schematic layout structural diagram of the laser array and the optical detection component of the lidar with a paraxial optical path structure in an embodiment of the present application when viewed from the front. Figure 10C Show Figure 10B a schematic curve diagram of the ranging simulation result of the lidar in

[0127] As Figure 10AAs shown, the lidar 100 with a paraxial optical path structure is presented in this example, that is, there is no overlapping section between the transmitting optical path for transmitting signals and the detecting optical path for echo signals. In possible specific instances, the lidar 100 can be a mechanical lidar 100, that is, it includes a rotating mechanism. The number of lines of the lidar 100 can be more than 32 lines, such as 32 lines, 64 lines, 128 lines, 256 lines, etc. Among them, for 128 lines, if the laser 1011 and the optical detector 1041 form channels in a one-to-one manner, it means that there are 128 lasers 1011 and 128 optical detectors 1041 corresponding one-to-one to form 128 channels. Multiple lasers 1011 can be arranged in multiple columns.

[0128] In the optical transmission module 1000, the laser array includes the laser array 1001. The transmitted signal light output by each laser 1011 therein (which can be processed by the microlens array first) is sequentially processed by each concave lens 1022 and the main lens group unit 1021 (equivalent to a convex lens) of the first optical component 1002, and then exits the lidar 100 and irradiates the obstacle P. After reflection, an echo signal is formed. The echo signal enters the lidar 100 and is sequentially converged by the receiving lens group unit 1051 (equivalent to a convex lens) and each concave lens 1052 of the optional second optical component 1005 and then directed to the optical detection module 1003. The optical detection components in the optical detection module 1003 can include the optical detector array 1004, and the optical detector 1041 corresponding to the channel of the echo signal can detect the echo signal.

[0129] Among them, the first optical component 1002 and the second optical component 1005 respectively form an extended equivalent focal length, for example, M times the focal length of the original lens group, so as to improve the ranging ability of the lidar 100 to be able to detect more distant obstacles P. Optionally, M can be a magnification factor of more than 1.5 times.

[0130] Based on Figure 10A the lidar 100 with a paraxial optical path structure, the layout structures of the laser array 1001B and the optical detector array 1004B shown, for example, Figure 10B can be adopted. Among them, two columns of lasers 1011B are arranged non-aligned, and two columns of optical detectors 1041B are arranged non-aligned.

[0131] Based on using the lidar 100 with a paraxial optical path structure based on Figure 10A and Figure 10B for ranging simulation, the simulation results are as shown in Figure 10C In Figure 10CAmong them, the horizontal axis is the measurable maximum distance (corresponding to the ranging ability of the lidar 100), and the vertical axis is the detection probability. It can be seen that at a detection probability of 90%, the measurable maximum distance reaches approximately 90 meters. Without adopting the solution of the embodiment of the present application, the measurable maximum distance of the same type of lidar is only about 45 meters. Therefore, by the solution of extending the focal length to improve the ranging distance in the embodiment of the present application, the actual ranging ability can be improved by more than 2 times.

[0132] In addition to being applied to lidars with a paraxial optical path structure, in some embodiments, the solution of the present application can also be applied to lidars with a coaxial optical path structure. Coaxial means that there is the same optical path segment between the emission optical path and the detection optical path.

[0133] As Figure 11A shown, a schematic structural diagram of a lidar with a coaxial optical path structure in an embodiment of the present application is shown.

[0134] The lidar includes:

[0135] A beam splitting unit 1103 disposed in the overlapping optical path segment, adapted to receive an emission signal from a first optical path segment communicating with a laser array (laser array 1101 in this example) and deflect or directly transmit it to the overlapping optical path segment, and adapted to receive an echo signal from the overlapping optical path segment and directly transmit or deflect it to a second optical path segment communicating with a photodetector array 1102; wherein, the main lens group unit 1104 (such as the main lens group in the foregoing embodiment) and the first divergence unit 1105 (such as the concave lens array in the foregoing embodiment) in the first optical assembly are respectively disposed in the overlapping optical path segment and the first optical path segment.

[0136] Exemplarily, the beam splitting unit 1103 can be implemented by, for example, a reflector or a polarization unit (such as a polarizing plate, a polarization prism, etc.). In the illustrated example, the emission signal output by the laser array can first be diverged by the first divergence unit 1105 disposed in the first optical path segment and then enter the beam splitting unit 1103, so as to be redirected (such as turned, such as reflected, etc.) by the beam splitting unit 1103 to the overlapping optical path segment (i.e., the optical path segment shared by the emission optical path and the detection optical path), and transmitted leftward through the overlapping optical path segment to the main lens group unit 1104, and then emitted after being converged, as indicated by the black solid arrow in the figure for the emission optical path.

[0137] Further, the lidar further includes a scanning unit 1106 (such as a galvanometer mirror or a rotating mirror) to select the transmission signal of the channel to be detected and emit it from the lidar. The main lens group unit 1104 (an exemplary convex lens is shown in the figure) and the first divergence unit 1105 cooperate to obtain a relatively extended equivalent focal length of the optical emission module; and, select the echo signal of the channel to be detected to turn into the overlapping optical path section, and transmit it to the right to the beam splitting unit 1103, and be redirected (such as directly emitted) by the beam splitting unit 1103 to the second optical path section connecting the optical detection component (the laser array 1102 in this example), and transmit along the second optical path section to the laser array 1102, as indicated by the gray arrow in the figure for the receiving optical path. Possibly, the scanning unit 1106 may include one or more resonant single-axis microelectromechanical system (MEMS) galvanometer mirrors to perform two-dimensional rotation to select the transmission signal and echo signal of the channel to be detected for transmission.

[0138] In the illustrated alternative example, only a convex lens 1107 may be provided in the second optical path section to converge the echo signal, and no concave lens is provided.

[0139] By configuring a certain proportional relationship between the focal lengths of the optical detection module (RX end) and the optical emission module (TX end), for example, the equivalent focal length of the optical detection module is several times (such as K = 3.5 times) that of the first optical component; and optionally, in the laser array 1101 of the laser array, the laser can use an edge-emitting laser (EEL) to utilize its characteristics of small light-emitting area and high brightness to illuminate the entire receiving field of view; in the photodetector array 1102 of the optical detection component, the photodetector can be implemented by SiPM, and the size of the photodetector array 1102 can also be several times (such as K) that of the laser array 1101. Thus, an ultra-long detection focal length is obtained, greatly improving the ranging ability of the lidar, such as from 200 meters to 300 meters, etc.

[0140] For another example Figure 11B as shown, the difference from Figure 11A the embodiment is that in the laser array 1101B of the laser array, the laser can be implemented by VCSEL to replace Figure 11A the EEL in the embodiment to further improve the ranging ability. Correspondingly, in this example, a microlens array 1109 can be correspondingly provided (a convex lens can also be additionally added in the first optical path section, etc.) to compress the divergence angle of the VCSEL and leave the periphery of the light exit aperture for the detection optical path. See Figure 11B In the figure, the divergence angle of the laser is compressed and transmitted along the middle part of the coaxial optical path (indicated by the thin solid line arrow), while the echo signal is transmitted in the peripheral area relative to the middle part (indicated by the thick solid line arrow).

[0141] Please refer to Figure 12Aand Figure 12B As shown in Figure 12B , it is used to illustrate the effect of encapsulating the optical path section between each laser and the corresponding concave lens in a sleeve in the embodiments of the present application. Wherein, the inner wall of the sleeve is made of an absorbing material to absorb light.

[0142] As Figure 12A Shown in the optical path diagram, taking the emission optical path as an example. Without using a sleeve, although the magnification of the light emitting surface can also be achieved, it is necessary to maintain the size of the focal length of the main lens group * vertical angular resolution. Otherwise, the emission signal (such as C) of the light emitting points near the edge on the laser 1201 may avoid the concave lens (concave lens 1202) and enter the main lens group unit (such as the main lens group, not drawn in this figure). The emission signal that does not pass through the first divergence unit will be defocused, and the echo signal that is likely to be formed after being sent out by the main lens group unit at a larger divergence angle may be received by the photodetectors of other channels, thus forming crosstalk. Therefore, this part of the potential stray light can be absorbed by the absorbing material.

[0143] As Figure 11B Shown in the optical path diagram, by encapsulating the optical path section between the laser 1201 and the corresponding concave lens 1202 with the sleeve 1203, the emission signal that originally avoided the concave lens 1202 can be reflected and restricted to pass through the concave lens 1202 and then reach the main lens group unit. Then, this part of the emission signal will not be defocused, and thus a light emitting area that is the same as or similar to the size of the concave lens can be achieved. For VCSEL, since the light emitting area is increased, the corresponding peak power is also increased.

[0144] Similarly, as Figure 12C Shown, it is used to illustrate the effect after encapsulating the optical path section between the echo signal corresponding concave lens 1302 in the sleeve 1303 to each detector 1301 in the embodiments of the present application. The optical path is similar to the transmitting end, and it also absorbs the potential stray light, thereby improving the signal-to-noise ratio. Details are not described here again.

[0145] In summary, the lidar provided in the present application includes: a laser array arranged in a linear array or a planar array, disposed on the focal plane of the first optical component, and the first optical component, disposed in the emission optical path, having an equivalent focal length greater than the focal length of the main lens group unit at the emission end; and / or, a photodetector array arranged in a linear array or a planar array, disposed on the focal plane of the second optical component, and the second optical component, disposed in the reception optical path, having an equivalent focal length greater than the focal length of the main lens group unit at the reception end. In the embodiments of the present application, by setting the first optical component at the light emission end, the power density within the point cloud field of view angle area is increased, and / or, by setting the second optical component at the reception end, the background light noise power within the point cloud field of view angle area is reduced, thereby improving the ranging ability of the lidar.

[0146] The above embodiments are only illustrative of the principles and effects of the present application and are not intended to limit the present application. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed in the present application should still be covered by the claims of the present application.

Claims

1. A light emitting device, characterized in that, For a lidar, the light emitting device includes: A laser array including a plurality of lasers arranged in a linear array or a planar array. The lasers in the laser array are configured to output emission signals, and the emission signals are transmitted along an emission optical path. A first optical component disposed on the emission optical path and configured with an equivalent focal length greater than a first preset value. Wherein, the first optical component includes a first main lens group unit and a first microlens group unit, and the first preset value is the focal length of the first main lens group unit. Wherein, The equivalent focal length of the first optical component is M times the focal length of the first main lens group unit, M > 1. The first microlens group unit is disposed between the laser array and the first main lens group unit.

2. The optical emission device according to claim 1, wherein The first microlens group unit includes: a concave lens array including a plurality of concave lenses, and one concave lens corresponds to one laser.

3. The optical emission device according to claim 2, wherein The vertical pitch between adjacent concave lenses in the concave lens array is not less than the height of the light emitting surface of one laser in the laser array.

4. The optical emission device according to claim 2, characterized in that, The vertical pitch between adjacent concave lenses in the concave lens array is the same as the center spacing between adjacent lasers in the laser array.

5. The optical emission device according to claim 1, characterized in that, The first microlens group unit includes a microlens array.

6. The optical emission device according to claim 5, characterized in that, The light emitting surface of the lasers in the laser array includes a plurality of light emitting points, and one microlens in the microlens array corresponds to one light emitting point.

7. The optical emission device according to claim 6, wherein The pitch between adjacent microlenses in the microlens array is the same as the pitch between adjacent light emitting points among the plurality of light emitting points.

8. The optical emission device according to claim 1, characterized in that The laser array includes N columns of lasers arranged in an interleaved manner, where N > M.

9. A light detection device, characterized in that, For a lidar, the light detecting device includes: A photodetector array including a plurality of photodetectors arranged in a linear array or a planar array. The photodetectors in the photodetector array are configured to detect, from a receiving optical path, an echo signal reflected after the emission signal reaches an object. A second optical component disposed on the receiving optical path and configured with an equivalent focal length greater than a second preset value. Wherein, the second optical component includes a second main lens group unit and a second microlens group unit at the receiving end, and the second preset value is the focal length of the second main lens group unit. Wherein, The equivalent focal length of the second optical component is P times the focal length of the second main lens group unit, P > 1. The second microlens group unit is disposed between the photodetector array and the second main lens group unit.

10. The optical detection device according to claim 9, characterized in that, The second microlens group unit includes: a concave lens array including a plurality of concave lenses, and one concave lens corresponds to one photodetector.

11. The optical detection device according to claim 10, characterized in that, The vertical pitch between adjacent concave lenses in the concave lens array is greater than the height of the receiving surface of one photodetector in the photodetector array.

12. The optical detection device according to claim 10, wherein The pitch between longitudinally adjacent concave lenses in the concave lens array is equal to the center spacing between adjacent photodetectors in one column of the photodetector array.

13. The optical detection device according to claim 9, characterized in that, The photodetector array includes Q columns of photodetectors arranged in an interleaved manner, where Q > P.

14. A lidar, characterized in that, Includes: The light emitting device according to any one of claims 1-8; And The light detecting device according to any one of claims 9-13.

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