Emission mirror group and laser radar

Abstract

The invention is suitable for the technical field of laser radar detection, and provides a transmitting mirror group and a laser radar. The equivalent focal length in the horizontal direction and the equivalent focal length in the vertical direction of the transmitting lens group are different, and the focal plane in the horizontal direction and the focal plane in the vertical direction of the transmitting lens group coincide; the transmitting lens group comprises a first lens, a second lens, a third lens and a fourth lens with positive bending force which are sequentially arranged from an object plane to an image plane; wherein at least one refractive surface of the third lens is a cylindrical surface, at least one refractive surface of the fourth lens is a cylindrical surface, and an included angle is formed between the axis of the cylindrical surface in the third lens and the axis of the cylindrical surface in the fourth lens. According to the transmitting mirror group and the laser radar provided by the invention, the detail distinguishing capability of the laser radar can be improved to a certain extent.

Description

Technical Field

[0001] This application belongs to the technical field of lidar detection, and particularly relates to a transmitting lens group and a lidar. Background Art

[0002] With the continuous development of intelligent assisted driving and driverless technologies, higher requirements are put forward for factors such as the performance, size, and cost of vehicle-mounted lidars. As the light-emitting unit of lidars, semiconductor lasers are undoubtedly the core components of lidars. Among them, Vertical Cavity Surface Emitting Lasers (VCSELs) are increasingly widely used in lidars due to many advantages such as low cost, easy integration, and good environmental stability.

[0003] In lidars, the method of stacking light sources and detectors is usually used to increase the number of radar lines, or devices such as galvanometers and micro-galvanometer MEMS (Micro-Electro-Mechanical System) are used to scan the light beam to increase the equivalent number of radar lines. However, adopting the former corresponding solution will undoubtedly double the cost of the lidar and increase the size of the lidar; while adopting the latter corresponding solution, problems such as the stability and power consumption of the lidar are pain points that are difficult to solve.

[0004] A new form of lidar is to increase the number of radar lines by reducing the size of the detector. However, VCSELs are not suitable for the above-mentioned lidars because of the low power density in the light-emitting area. The reason is that the spot size formed by VCSELs in the detection area is too large, the coverage area is too large, and the detail resolution ability is poor. Summary of the Invention

[0005] The purpose of this application is to provide a transmitting lens group and a lidar, aiming to improve the technical problem of poor detail resolution ability of lidars using VCSELs in the prior art.

[0006] This application is implemented as follows. In the first aspect, a transmitting lens group is provided. The equivalent focal length in the horizontal direction and the equivalent focal length in the vertical direction of the transmitting lens group are different, and the focal planes in the horizontal direction and the vertical direction of the transmitting lens group coincide.

[0007] In some embodiments, the transmitting lens group includes a first lens, a second lens, a third lens, and a fourth lens with positive dioptric power arranged in sequence from the object plane to the image plane; wherein, at least one refractive surface of the third lens is a cylindrical surface, at least one refractive surface of the fourth lens is a cylindrical surface, and the axis of the cylindrical surface in the third lens and the axis of the cylindrical surface in the fourth lens are arranged at an angle.

[0008] The third lens, the first lens, and the second lens form a first collimating lens group. The fourth lens, the first lens, and the second lens form a second collimating lens group. The equivalent focal lengths of the second collimating lens group and the first collimating lens group are different, but their focal planes coincide.

[0009] In some embodiments, the axis of the cylindrical surface of the third lens is perpendicular to the axis of the cylindrical surface of the fourth lens.

[0010] In some embodiments, the first lens, the second lens, the third lens, and the fourth lens satisfy the following relational expressions:

[0011] 1.4 < n1, n4 < 2.1; 1.8 < n2, n3 < 2.1;

[0012] Wherein, n1 is the refractive index of the first lens at a wavelength of 900 nm; n2 is the refractive index of the first lens at a wavelength of 900 nm; n3 is the refractive index of the first lens at a wavelength of 900 nm; n4 is the refractive index of the first lens at a wavelength of 900 nm.

[0013] In some embodiments, the first lens has a negative bending power, the object side is concave, and the image side is concave or convex; the second lens has a positive bending power, the object side is concave, and the image side is convex; the third lens has a positive bending power.

[0014] In some embodiments, the emitting lens group further includes a diaphragm, and the diaphragm is located between the third lens and the fourth lens.

[0015] In some embodiments, the apertures of the first lens, the second lens, and the third lens increase in sequence.

[0016] In some embodiments, the ratio of the focal length in the horizontal direction to the focal length in the vertical direction of the emitting lens group is greater than 1.5.

[0017] In a second aspect, a lidar is provided. The lidar includes an emitting module, an emitting lens group, a receiving lens group, and a receiving module arranged in sequence. The emitting module is configured to provide a detection beam, the emitting lens group is configured to collimate the detection beam, the receiving lens group is configured to receive an echo beam formed after the collimated detection beam is reflected by a detected object, and the receiving module is configured to receive and process the echo beam conducted by the receiving lens group.

[0018] In some embodiments, the emitting module includes a plurality of emitting units arranged in an array, and all the emitting units are integrated on the same circuit board;

[0019] And / or, the receiving module includes a plurality of receiving units arranged in an array, and all the receiving units are integrated on the same circuit board.

[0020] In some embodiments, the transmitting module includes a plurality of transmitting units arranged in an array, and all the transmitting units are integrated on the same circuit board; the transmitting unit is a vertical cavity surface emitting laser.

[0021] The technical effect of the present application relative to the prior art is as follows: The transmitting mirror group provided by the embodiments of the present application adopts an asymmetric design, that is, the equivalent focal lengths in the horizontal direction and the vertical direction are not the same; at the same time, the focal planes in the horizontal direction and the vertical direction are designed at the same position. In this way, due to the difference between the equivalent focal lengths in the horizontal direction and the vertical direction, the magnification ratios of the emission spots emitted by the lidar using the transmitting mirror group provided by the embodiments of the present application in the horizontal direction and the vertical direction in the far field are different, presenting a non-uniform magnification relationship in the horizontal direction and the vertical direction; at the same time, the coincidence of the focal planes in the horizontal direction and the vertical direction can enable the detection beams emitted by the transmitting module in the lidar using the transmitting mirror group provided by the embodiments of the present application to be effectively collimated, ensuring the ranging ability of the lidar. Among them, the difference between the equivalent focal lengths in the horizontal direction and the vertical direction of the transmitting mirror group can compress the above-mentioned emission spot in the horizontal direction or the vertical direction to form a compressed spot, which can improve the power density of the emitted light and enhance the ranging ability of the lidar; at the same time, the compression of the emission spot can reduce the size of the emission spot and enhance the detection ability of the lidar for small objects, that is, it can improve the detail resolution ability of the lidar to a certain extent, and is applicable to lidars using VCSELs and other types of lidars.

[0022] It can be understood that the beneficial effects of the second aspect can refer to the relevant descriptions in the first aspect above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments of the present application or the description of the prior art. Obviously, the following described drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 is a schematic side view structure diagram of the transmitting mirror group provided by the embodiments of the present application;

[0025] Figure 2 is a schematic top view structure diagram of the transmitting mirror group provided by the embodiments of the present application;

[0026] Figure 3It is a schematic diagram for comparing the energy distributions of the emission spots at 10 m before and after horizontal compression by the emission lens group. Among them, Figure 3 in (a) is the schematic diagram of the energy distribution of the emission spot at 10 m without horizontal compression by the emission lens group, Figure 3 in (b) is the schematic diagram of the energy distribution of the emission spot at 10 m after horizontal compression by the emission lens group;

[0027] Figure 4 It is a schematic diagram of the optical path principle of the lidar provided by the embodiment of the present application. The arrows in the figure indicate the beam propagation direction;

[0028] Figure 5 It is a schematic diagram of the first receiving lens group and the second receiving lens group used in an embodiment of the present application to jointly detect and achieve enhanced display of the region of interest;

[0029] Figure 6 It is Figure 5 a schematic diagram after the fusion of the detection point cloud corresponding to the first module and the detection point cloud corresponding to the second module in the corresponding lidar;

[0030] Figure 7 It is a schematic diagram of the first receiving lens group and the second receiving lens group used in another embodiment of the present application to jointly detect and achieve enhanced display of the region of interest;

[0031] Figure 8 It is a schematic diagram of the point cloud with the upper and lower displacements to achieve encryption of the region of interest;

[0032] Figure 9 It is a schematic diagram of the structure of the emission module used in the embodiment of the present application;

[0033] Figure 10 It is a schematic diagram of the structure of the first receiving module used in the embodiment of the present application.

[0034] Explanation of reference numerals:

[0035] 100. Emission module; 110. Emission module; 111. Emission unit; 120. Emission lens group; 121. First lens; 122. Second lens; 123. Third lens; 124. Fourth lens; 125. Diaphragm; 200. Scanning module; 300. Receiving module; 310. First module; 311. First receiving lens group; 3111. First receiving lens; 3112. Receiving mirror; 3113. Second receiving lens; 312. First receiving module; 3121. First detector; 320. Second module; 321. Second receiving lens group; 3211. Third receiving lens; 3212. Fourth receiving lens; 322. Second receiving module; a1. First detection area; a2. Second detection area; a21. First area; a22. Second area. Detailed implementation manners

[0036] The embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application and should not be construed as limiting the present application.

[0037] In the description of the present application, it should be understood that the orientation or positional relationships indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present application.

[0038] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality" means two or more, unless otherwise specifically defined.

[0039] In the present application, unless otherwise clearly specified and defined, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0040] In order to make the purpose, technical solutions and advantages of the present application more clear and understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0041] A lidar generally includes a transmitting module, a transmitting mirror group, a receiving mirror group, and a receiving module arranged in sequence. The transmitting module is used to provide a detection beam. The transmitting mirror group is used to collimate the detection beam. The receiving mirror group is used to receive the echo beam formed after the collimated detection beam is reflected by the detected object. The receiving module is used to receive and process the echo beam conducted by the receiving mirror group.

[0042] In addition, some lidars are also provided with a scanning module between the transmitting mirror group and the receiving mirror group, so that the collimated detection beam can be emitted in the form of a scanning beam, increasing the field of view of the lidar. The working principle of this kind of lidar is as follows:

[0043] During use, the transmitting module emits a detection beam. This detection beam forms a scanning beam through the scanning module and then irradiates the detection area, forming an array of light spots or a line of light spots for illumination in the detection area. Then, the above scanning beam is reflected by an object (i.e., the detected object) in the detection area to form an echo beam. After being reflected by the scanning module, the echo beam is received by the receiving mirror group and converged to the receiving module. Then, the receiving module processes the received echo beam and transmits the processed signal to an external signal processing device connected thereto, or to a signal processing device built into the lidar, and then the detection data is obtained through analysis by the signal processing device.

[0044] In the related art, the above-mentioned transmitting mirror group generally adopts a symmetric design, that is, the focal length in the horizontal direction and the focal length in the vertical direction of the transmitting mirror group are the same. However, with this design, the spot size of the lidar is too large, the coverage area is too large, and the detail resolution ability is poor.

[0045] Please refer to Figures 1 to 3 As shown, to solve the above problems, the embodiment of the present application provides a transmitting mirror group. The equivalent focal length in the horizontal direction and the equivalent focal length in the vertical direction of this transmitting mirror group are different, and the focal plane in the horizontal direction and the focal plane in the vertical direction of the transmitting mirror group coincide.

[0046] The transmitting mirror group in this embodiment generally includes a plurality of lenses. One or more of these lenses can be used for collimating the detection beam in the vertical direction, and one or more lenses can be used for collimating the detection beam in the horizontal direction. It can be understood that the lenses used for collimating the detection beam in the vertical direction can partially coincide with the lenses used for collimating the detection beam in the horizontal direction, that is, some lenses can participate in collimating the detection beam in both the vertical direction and the horizontal direction.

[0047] By reasonably setting parameters such as the surface shape and thickness of each lens in the transmitting mirror group, the equivalent focal length in the horizontal direction and the vertical direction of the transmitting mirror group can be made different, but the focal plane in the horizontal direction and the focal plane in the vertical direction coincide.

[0048] The emission lens group provided by the embodiment of the present application adopts an asymmetric design, that is, the equivalent focal lengths in the horizontal direction and the vertical direction are not the same; at the same time, the focal planes in the horizontal direction and the vertical direction are designed at the same position. In this way, due to the difference between the equivalent focal lengths in the horizontal direction and the vertical direction, the magnification ratios of the emission spots emitted by the lidar using the emission lens group provided by the embodiment of the present application in the horizontal direction and the vertical direction in the far field are different, presenting a non-proportional magnification relationship in the horizontal direction and the vertical direction; at the same time, the coincidence of the focal planes in the horizontal direction and the vertical direction can also enable the detection beams emitted by the emission module in the lidar using the emission lens group provided by the embodiment of the present application to be effectively collimated, ensuring the ranging ability of the lidar. Among them, the difference between the equivalent focal lengths in the horizontal direction and the vertical direction of the emission lens group can compress the above-mentioned emission spot in the horizontal direction or the vertical direction to form a compressed spot, which can improve the power density of the emitted light and enhance the ranging ability of the lidar; at the same time, the compression of the emission spot can reduce the size of the emission spot, as Figure 3 shown, enhancing the detection ability of the lidar for small objects, that is, it can improve the detail resolution ability of the lidar to a certain extent, and is applicable to lidars using VCSELs and other types of lidars.

[0049] Please refer to Figure 1 and Figure 2 shown, in some embodiments, the above-mentioned emission lens group includes a first lens 121, a second lens 122, a third lens 123 and a fourth lens 124 with positive refractive power, which are sequentially arranged from the object plane (i.e., the position where the above-mentioned emission module 110 is located) to the image plane.

[0050] Among them, at least one refractive surface of the third lens 123 is a cylindrical surface, and at least one refractive surface of the fourth lens 124 is a cylindrical surface. That is, both the third lens 123 and the fourth lens 124 include at least one cylindrical surface, and the other refractive surface of the third lens 123 and the fourth lens 124 can be a cylindrical surface, a spherical surface, or an aspherical surface. The cylindrical axes of the third lens 123 and the fourth lens 124 are arranged at an angle. The above-mentioned refractive surface refers to the surface through which the light beam passes, that is, the incident surface and the exit surface of the third lens 123 and the fourth lens 124. The above-mentioned third lens 123 and the fourth lens 124 both include at least one cylindrical surface, and the other refractive surface of the third lens 123 and the fourth lens 124 can be a cylindrical surface, a spherical surface, or an aspherical surface, including but not limited to the following situations: First, the incident surface of the third lens 123 is a cylindrical surface, and the exit surface is a cylindrical surface, a spherical surface, or an aspherical surface. The incident surface of the fourth lens 124 is a cylindrical surface, and the exit surface is a cylindrical surface, a spherical surface, or an aspherical surface. Second, the exit surface of the third lens 123 is a cylindrical surface, the incident surface is a cylindrical surface, a spherical surface, or an aspherical surface, and the exit surface of the fourth lens 124 is a cylindrical surface, and the incident surface is a cylindrical surface, a spherical surface, or an aspherical surface. Third, the exit surface of the third lens 123 is a cylindrical surface, the incident surface is a cylindrical surface, a spherical surface, or an aspherical surface, and the incident surface of the fourth lens 124 is a cylindrical surface, and the exit surface is a cylindrical surface, a spherical surface, or an aspherical surface. Fourth, the incident surface of the third lens 123 is a cylindrical surface, the exit surface is a cylindrical surface, a spherical surface, or an aspherical surface, and the exit surface of the fourth lens 124 is a cylindrical surface, and the incident surface is a cylindrical surface, a spherical surface, or an aspherical surface.

[0051] The fact that the cylindrical axes of the third lens 123 and the fourth lens 124 are arranged at an angle means that the angle between them is non-zero, and it can be determined according to actual use needs, such as 30°, 60°, 15°, 45°, etc.

[0052] The third lens 123, the first lens 121, and the second lens 122 form a first collimating lens group. The fourth lens 124, the first lens 121, and the second lens 122 form a second collimating lens group. The equivalent focal lengths of the second collimating lens group and the first collimating lens group are different, but their focal planes coincide. Specifically, the first collimating lens group can be a collimating lens group in the vertical direction, and the second collimating lens group can be a collimating lens group in the horizontal direction; or the second collimating lens group is a collimating lens group in the vertical direction, and the first collimating lens group is a collimating lens group in the horizontal direction. It can be determined according to actual use needs.

[0053] The emission lens group adopts the structure provided by this embodiment, with few lenses, simple structure, and is convenient for design and assembly.

[0054] In some embodiments, the cylindrical axes of the third lens 123 and the fourth lens 124 are perpendicular to each other. The emission lens group adopts the structure provided by this embodiment, with few lenses, simple structure, and is convenient for design and assembly.

[0055] In some embodiments, the emission lens group further includes a diaphragm 125, which is located between the third lens 123 and the fourth lens 124.

[0056] The diaphragm 125 refers to an entity that restricts the light beam in an optical system. It can be the edge of a lens, a frame, or a specially set perforated screen. The diaphragm 125 in this embodiment is mainly used to limit the size of the emission field of view and is the field stop 125.

[0057] In the case where the equivalent focal length of the first collimating lens group is less than that of the second collimating lens group, the detection beam emitted by the emission module 110 in the lidar using the emission lens group provided in this embodiment is collimated in the vertical direction or the horizontal direction after passing through the first collimating lens group. Thus, if the diaphragm 125 is placed behind the fourth lens 124, the size of the third lens 123 will increase; if the diaphragm 125 is placed in front of the third lens 123, the size of the fourth lens 124 will increase. This will be very disadvantageous in application scenarios with strict requirements on the volume of the lidar, such as vehicle-mounted lidar. Therefore, setting the diaphragm 125 of the emission lens group between the third lens 123 and the fourth lens 124 is most beneficial for compressing the size of the entire emission lens group.

[0058] In some embodiments, the first lens 121, the second lens 122, the third lens 123, and the fourth lens 124 satisfy the following relational expressions:

[0059] 1.4 < n1, n4 < 2.1; 1.8 < n2, n3 < 2.1;

[0060] Wherein, n1 is the refractive index of the first lens 121 at a wavelength of 900 nm; n2 is the refractive index of the first lens 121 at a wavelength of 900 nm; n3 is the refractive index of the first lens 121 at a wavelength of 900 nm; n4 is the refractive index of the first lens 121 at a wavelength of 900 nm.

[0061] During design, by reasonably designing the surface shape and diopter of the first lens 121, the second lens 122, the third lens 123, and the fourth lens 124, the above relational expressions can be satisfied by each lens, which is beneficial to reducing aberrations such as spherical aberration, astigmatism, and distortion generated by the detection beam passing through each lens in the emission lens group, and is beneficial to improving the collimation efficiency of the emission lens group and the quality of energy convergence.

[0062] In some embodiments, the apertures of the first lens 121, the second lens 122, and the third lens 123 increase in sequence.

[0063] During use, generally, the first lens 121, the second lens 122, and the third lens 123 are installed in the same lens barrel. By adopting the solution provided in this embodiment, the first lens 121, the second lens 122, and the third lens 123 are convenient for assembly, which helps to improve the assembly speed of the emission lens group.

[0064] In some embodiments, the ratio of the focal length in the horizontal direction to the focal length in the vertical direction of the emission lens group is greater than 1.5.

[0065] By adopting the solution provided in this embodiment, the spot size of the emission module 110 in the far field in the lidar can be effectively compressed to a certain extent.

[0066] In some embodiments, the first lens 121 has a negative bending power, the overall object side is concave, and the image side is concave or convex. Both the object side and the image side can be spherical or aspherical. The second lens 122 has a positive bending power, the overall object side is concave, and the image side is convex. The third lens 123 has a positive bending power, and one of the image side or the object side is a cylindrical surface, and the other surface can be a cylindrical surface, a spherical surface, or an aspherical surface.

[0067] By adopting the solution provided in this embodiment, the surface shapes of the lenses are simple and convenient for design.

[0068] In the above embodiments, the materials of the first lens 121, the second lens 122, the third lens 123, and the fourth lens 124 can be glass, plastic, or a glass-plastic hybrid material. The materials of the lenses can be the same or different, and can be specifically determined according to the usage requirements.

[0069] For ease of understanding, three specific embodiments are given below to illustrate the specific setting methods of the first lens 121, the second lens 122, the third lens 123, and the fourth lens 124. It can be understood that in other embodiments, the first lens 121, the second lens 122, the third lens 123, and the fourth lens 124 can also adopt other setting methods as long as the above functions can be achieved.

[0070] First Embodiment:

[0071]

[0072] Second Embodiment:

[0073]

[0074] Third Embodiment:

[0075]

[0076] In another embodiment of the present application, a lidar is further provided. The lidar includes a transmitting module, a transmitting mirror group, a receiving mirror group, and a receiving module arranged in sequence. The transmitting module is used to provide a detection beam, the transmitting mirror group is used to collimate the detection beam, the receiving mirror group is used to receive the echo beam formed after the collimated detection beam is reflected by the detected object, and the receiving module is used to receive and process the echo beam conducted by the receiving mirror group.

[0077] The lidar provided in the embodiment of the present application includes the transmitting mirror group provided in each of the above embodiments. The transmitting mirror group has the same structural features and the same functions as the transmitting mirror group in each of the above embodiments, and will not be elaborated here.

[0078] In some embodiments, the transmitting module includes a plurality of transmitting units arranged in an array, and all the transmitting units are integrated on the same circuit board.

[0079] The array can be a one-dimensional linear array or a two-dimensional array, which can be determined according to actual usage needs. Each transmitting unit may include one laser emitting chip or multiple laser emitting chips, which can be determined according to actual usage needs.

[0080] In the traditional solution, the transmitting module in a multi-line lidar generally adopts a discrete device solution, that is, the transmitting module includes a plurality of independent transmitting modules arranged at intervals. The solution provided in this embodiment integrates all the transmitting units in the transmitting module on the same or multiple chips, which directly eliminates the gaps between the discrete devices and avoids the blind areas caused by the gaps.

[0081] In some embodiments, the receiving module includes a plurality of receiving units arranged in an array, and all the receiving units are integrated on the same circuit board.

[0082] The array can be a one-dimensional linear array or a two-dimensional array, which can be determined according to actual usage needs. Each receiving unit may include one detector or multiple detectors, which can be determined according to actual usage needs.

[0083] In the traditional solution, the receiving module in a multi-line lidar generally adopts a discrete device solution, that is, the receiving module includes a plurality of independent receiving modules arranged at intervals. The solution provided in this embodiment integrates all the receiving units in the receiving module on the same or multiple chips, which directly eliminates the gaps between the discrete devices and avoids the blind areas caused by the gaps.

[0084] In some embodiments, the transmitting module includes a plurality of transmitting units arranged in an array, all the transmitting units are integrated on the same circuit board, and the receiving module includes a plurality of receiving units arranged in an array, all the receiving units are integrated on the same circuit board. By adopting the solution provided in this embodiment, the receiving lens group and the transmitting lens group adopt a line-to-line solution, and distance detection can be realized by receiving through a linear array detector. This solution increases the number of lines of the radar by reducing the size of the detector, so that a higher number of detection lines can be obtained with a smaller radar size. At the same time, by adopting the solution provided in this embodiment, the lidar can have a compact structure and a smaller volume, which is beneficial to its miniaturization design.

[0085] In the above embodiments, each transmitting unit includes a laser emitting chip, each detecting unit includes a detector, and the number of transmitting units can be 1 / 3 to 1 / 10 of the number of detecting units. In this way, a higher number of detection lines can be obtained with a smaller lidar size.

[0086] In some embodiments, the transmitting unit is a vertical cavity surface emitting laser.

[0087] Compared with the commonly used edge emitting lasers (EEL), the vertical cavity surface emitting laser (VCSEL) light source has many advantages such as low temperature drift, low price, easy integration, and good environmental stability, and is gradually applied in lidar. However, problems such as its low energy density and large light emitting surface size limit its ranging ability, especially for linear array VCSEL light sources. When the linear array VCSELs are arranged in the vertical direction (the long side is parallel to the vertical direction), and the length of the linear array VCSEL light source is fixed, the focal length of the transmitting lens group can be calculated according to the target vertical field of view angle. However, since the horizontal size of the VCSEL cannot be made very small or making it small will reduce the power, the spot divergence angle in the horizontal direction is large and the power density is low. This results in that when using traditional technologies, VCSELs are not suitable for the above-mentioned linear array radar form. By adopting the solution provided in this embodiment, the size of the emission spot of the linear array VCSEL light source in the horizontal direction can be compressed, which can improve the energy density of the VCSEL in the radar detection area to a certain extent and enhance the detail resolution ability of the lidar.

[0088] Please refer to Figure 4As shown, in an embodiment of the present application, a lidar is provided. The lidar includes a transmitting module 100, a scanning module 200, and a receiving module 300 arranged in sequence. The transmitting module 100 is used to provide a detection beam. The scanning module 200 is used to form a scanning beam from the detection beam, and is also used to receive and reflect the echo formed after being reflected by the detected object. The echo includes a first reflected echo and a second reflected echo. Among them, the transmitting module 100 generally includes a transmitting module group composed of at least one laser, and may also include the transmitting mirror group provided in the above embodiments, which can be specifically determined according to the usage requirements. The scanning module 200 may include at least one of a rotating mirror and a galvanometer mirror, and may also include other devices that can form a scanning beam from the detection beam, which can be specifically determined according to the usage requirements.

[0089] The receiving module 300 includes a first module 310 and a second module 320. Each module includes a receiving module group and a receiving mirror group. Specifically, the first module 310 includes a first receiving mirror group 311 and a first receiving module group 312. The first receiving mirror group 311 is used to collect and converge the output of the first reflected echo. The first receiving module group 312 is used to receive and process the first reflected echo output by the first receiving mirror group 311.

[0090] The second module 320 includes a second receiving mirror group 321 and a second receiving module group 322. The second receiving mirror group 321 is used to collect and converge the output of the second reflected echo. The second receiving module group 322 is used to receive and process the second reflected echo output by the second receiving mirror group 321.

[0091] The detection area corresponding to the first receiving mirror group 311 and the detection area corresponding to the second receiving mirror group 321 have an overlapping area.

[0092] It can be understood that the size of the above overlapping area can be set according to the usage requirements. For example, it can be the entire detection area corresponding to the first receiving mirror group 311 or the second receiving mirror group 321, or it can be half, 1 / 4, or other ratios of the detection area corresponding to the first receiving mirror group 311 or the second receiving mirror group 321, which can be specifically determined according to the usage requirements.

[0093] The photosensitive detection areas of the first receiving module group 312 and the second receiving module group 322 correspond to the transmitting module group 110, and can effectively detect the echo reflected by the detected object in the detected area; the first receiving mirror group 311 and the second receiving mirror group 321 respectively correspond to the first receiving module group 312 and the second receiving module group 322, and can collect the echo reflected by the detected object.

[0094] The first receiving lens group 311 includes at least one lens. The second receiving lens group 321 includes at least one lens. The lens type, quantity, setting method, etc. in the second receiving lens group 321 may be the same as or different from those in the first receiving lens group 311, which can be determined according to actual usage needs. The first receiving module 312 generally includes at least one detector. The second receiving module 322 generally includes at least one detector. The model, setting method, etc. of the detectors in the second receiving module 322 may be the same as or different from those of the detectors in the first receiving module 312, which can be determined according to actual usage needs.

[0095] The working principle of the lidar provided in this embodiment is as follows:

[0096] The transmitting module 100 emits a detection beam. The detection beam forms a scanning beam through the scanning module 200 and then irradiates into the detection area, forming an array of light spots or a line of light spots for illumination in the detection area. Then, the above scanning beam is reflected by an object (i.e., the object to be detected) in the detection area to form an echo. After the echo is reflected by the scanning module 200, a part of it (i.e., the first reflected echo) is received by the first receiving lens group 311 and converged to the first receiving module 312, and another part (i.e., the second reflected echo) is received by the second receiving lens group 321 and converged to the second receiving module 322. Then, the first receiving module 312 and the second receiving module 322 process the received reflected echoes and transmit the processed signals to an external signal processing device connected thereto or a signal processing device built in the lidar, and then the detection data is obtained through analysis by the signal processing device.

[0097] During use, the overlapping area can be made to fall within the area of interest according to actual usage needs, so that the lidar can obtain a larger number of echo lines in the area of interest, realizing the encryption of the radar line number in the area of interest.

[0098] As described above, with the development of lidar technology, currently, pursuing lidars with higher line numbers has become a new development trend. However, the method of simply stacking the number of detectors in the receiving module 300 to increase the line number of the reflected echo beam finally obtained by the lidar will not only cause the problem of increased cost, but also lead to an increase in the size and power consumption of the lidar.

[0099] Through research by the inventors, it is found that in the application scenarios of lidar, users often pay more attention to a certain area in the point cloud field of view (such as the central area) rather than the entire detection area. In this way, it is possible to only improve the resolution of the region of interest (ROI) of the lidar, without having to improve the resolution of all detection areas of the entire lidar, which can meet people's requirements for improving the resolution of the lidar. Compared with improving the resolution of all detection areas of the entire lidar, it can also reduce the cost of the lidar.

[0100] The lidar provided by the embodiments of the present application changes the design of the traditional single receiving mirror group of the lidar, and uses two receiving mirror groups (i.e., the first receiving module 312 and the second receiving module 322) to receive the reflected echo, and makes the detection area corresponding to the first receiving mirror group 311 and the detection area corresponding to the second receiving mirror group 321 have an overlapping area. In this way, when in use, the overlapping area can be made to fall within the area of interest according to the usage needs, so that the number of echo lines in the area of interest obtained by the lidar is relatively large, realizing the encryption of the radar line number in the area of interest, thereby improving the resolution of the lidar in the area of interest, and can also effectively control the cost of the lidar.

[0101] In some embodiments, at least one of the optical parameters of the first receiving mirror group 311 and the second receiving mirror group 321 is different. The optical parameters mentioned here can be any one of the focal length, field of view parameter, resolution, or other optical parameters that can affect the number of receiving lines of the lidar. The above-mentioned field of view parameter can be the field of view angle or the field of view center position, and can be specifically determined according to the usage needs.

[0102] By adopting the solution provided by this embodiment, during the design process, by adjusting the differences in optical parameters such as the focal length, field of view parameter, and resolution of the two receiving mirror groups (the first receiving mirror group 311 and the second receiving mirror group 321), it is possible to increase the number of lines of the reflected echo beams obtained in the detection area of interest, so that a relatively large amount of point cloud can be obtained in the detection area of interest, and the resolution of the detection area of interest can be improved.

[0103] In some embodiments, the optical parameters include at least one of the focal length, field of view parameter, and resolution. Among them, the field of view parameter includes at least one of the field of view angle and the field of view center position.

[0104] With the setting method of the optical parameters in this embodiment, it is easier to increase the number of echo beams received by the radar compared with using other optical parameters, which is convenient for the design of the lidar.

[0105] Such as Figure 5 and Figure 6As shown, in some embodiments, the focal length of the first receiving lens group 311 is different from that of the second receiving lens group 321, that is, the focal length of one of the first receiving lens group 311 and the second receiving lens group 321 is less than that of the other receiving lens group. The detection area corresponding to the receiving lens group with the smaller focal length among the first receiving lens group 311 and the second receiving lens group 321 is the first detection area a1. The detection area corresponding to the receiving lens group with the larger focal length among the first receiving lens group 311 and the second receiving lens group 321 is the second detection area a2. More than 1 / 2 of the area of the second detection area a2 is located within the first detection area a1. In some embodiments, almost all of the area of the second detection area a2 is located within the first detection area a1.

[0106] For ease of description, hereinafter, the receiving lens group with the smaller focal length will be referred to as the short-focus lens group, and the receiving lens group with the larger focal length will be referred to as the long-focus lens group. Figure 6 The dots in the dotted box located above in represent the point cloud corresponding to the short-focus lens group, and the hollow dots in the dotted box located below represent the point cloud corresponding to the long-focus lens group.

[0107] Among them, the detection range of the short-focus lens group is generally larger than that of the long-focus lens group. And with the same number of detectors, the angular resolution of the long-focus lens group is higher than that of the short-focus lens group. When used in this way, the short-focus lens group can be used to detect the environment to ensure the detection field of view of the lidar; the long-focus lens group can be used to detect the area of interest (such as the central area of the first detection area a1) within the first detection area a1 corresponding to the short-focus lens group to improve the resolution of the area of interest. Then, by fusing the point clouds of the short-focus lens group and the long-focus lens group together, enhanced display of the ROI can be achieved, as Figure 5 shown.

[0108] As Figure 7 and Figure 8 shown, in some other embodiments, the optical parameters of the first receiving lens group 311 and the second receiving lens group 321 are the same.

[0109] Adopting the solution provided in this embodiment facilitates the design and assembly of the lidar.

[0110] As Figure 4 shown, in some embodiments, the first receiving lens group 311 includes a first receiving lens 3111, a receiving mirror 3112, and a second receiving lens 3113 arranged in sequence along the propagation direction of the first reflected echo, and the second receiving lens group 321 includes a third receiving lens 3211 and a fourth receiving lens 3212 arranged in sequence along the propagation direction of the second reflected echo.

[0111] In this embodiment, the number of the first receiving lens 3111, the second receiving lens 3113, the third receiving lens 3211, and the fourth receiving lens 3212 can be one or more. Lenses with the same structure or different structures can be used, which can be specifically determined according to the usage requirements.

[0112] Among them, the setting of the receiving mirror 3112 can change the propagation path of the echo beam, which can be specifically determined according to the usage requirements.

[0113] The first receiving mirror group 311 and the second receiving mirror group 321 adopt the solution provided in this embodiment, with a simple structure, which is convenient for design and installation.

[0114] In some embodiments, the transmitting module 100 includes a transmitting module group 110 and a transmitting mirror group 120. The transmitting module group 110 is used to provide a light beam. The transmitting mirror group 120 is used to collimate the light beam and output a detection light beam.

[0115] The transmitting module group 110 can include an edge emitting laser (EEL) and / or a vertical cavity surface emitting laser (VCSEL). As Figure 9 shown, it is generally composed of multiple independently controllable transmitting units 111, etc., and can be arranged as a linear array or multiple linear arrays, which can be specifically determined according to the usage requirements.

[0116] The transmitting mirror group 120 collimates the light beam emitted by the transmitting module group 110 to form an array light spot or a linear light spot illumination in the area to be detected.

[0117] The transmitting module group 110 adopts the structure provided in this embodiment, with a simple structure, which is convenient for design and assembly.

[0118] In some embodiments, the transmitting module group includes laser emitting chips arranged in an array. All the laser emitting chips in this embodiment can be integrated on a circuit board, making the structure of the transmitting module group compact and convenient for assembly.

[0119] In some embodiments, the scanning module 200 includes a rotating mirror. The scanning module 200 adopts the structure provided in this embodiment, with a simple structure, which is convenient for operation.

[0120] In some embodiments, the second receiving module group 322 includes second detectors arranged in an array. As Figure 10 shown, the first receiving module group 312 includes first detectors 3121 arranged in an array.

[0121] The first receiving module 312 and the second receiving module 322 are respectively composed of a plurality of independently receiving detection units, etc., and can be arranged as a linear array or multiple linear arrays. Each detection unit generally includes a detector, or may include multiple detectors, which can be specifically determined according to the usage requirements.

[0122] The first detector and the second detector can respectively adopt SiPM (Silicon photomultiplier) arrays, APD (Avalanche Photo Diode) arrays, and SPAD (Single Photon Avalanche Diode) arrays.

[0123] The first receiving module 312 and the second receiving module 322 adopt the structure provided in this embodiment, with a simple structure and convenient for design.

[0124] In some embodiments, the lidar further includes a control module. The control module is electrically connected to the transmitting module 100, the scanning module 200, the first receiving module 312, and the second receiving module 322.

[0125] It can be understood that the above control module being electrically connected to the transmitting module 100, the scanning module 200, the first receiving module 312, and the second receiving module 322 means that the control module is electrically connected to the electric parts in the transmitting module 100, the scanning module 200, the first receiving module 312, and the second receiving module 322.

[0126] The control module can adopt a single-chip microcomputer, or an integrated structure including a CPU or other control chips, etc., which can be specifically selected according to the usage requirements. In this embodiment, the control module can synchronously control the transmitting module 100, the scanning module 200, the first receiving module 312, and the second receiving module 322 of the lidar according to the usage requirements.

[0127] The lidar adopting the structure provided in this embodiment has a relatively high degree of automation.

[0128] In a specific embodiment, the laser radar includes a transmitting module 100, a scanning module 200 and a receiving module 300 arranged in sequence. The receiving module 300 includes a first module 310 and a second module 320. The first module 310 includes a first receiving mirror group 311 and a first receiving module 312. The second module 320 includes a second receiving mirror group 321 and a second receiving module 322. The first receiving mirror group 311 includes a first receiving lens 3111, a receiving reflector 3112 and a second receiving lens 3113 arranged in sequence along the propagation direction of the first reflected echo, and the second receiving mirror group 321 includes a third receiving lens 3211 and a fourth receiving lens 3212 arranged in sequence along the propagation direction of the second reflected echo. The transmitting module 100 includes a transmitting module 110 and a transmitting mirror group 120. The transmitting mirror group 120 includes a transmitting mirror group provided in any of the above embodiments. The scanning module 200 includes a rotating mirror. The first receiving module 312 includes a first detector arranged in an array, and the second receiving module 322 includes a second detector arranged in an array.

[0129] The beam propagation path of the laser radar provided by this embodiment is as follows:

[0130] After the detection beam emitted by the transmitting module 110 passes through the transmitting mirror group, it is reflected by the reflector on the rotating mirror, thereby generating the radar's output light (i.e., scanning beam). The first receiving lens 3111, the receiving reflector 3112, and the second receiving lens 3113 constitute the long-focus receiving mirror group of the laser radar. The long-focus receiving mirror group focuses the echo generated by the object being irradiated by the output light to the first detector of the radar. The third receiving lens 3211 and the fourth receiving lens 3212 constitute the short-focus receiving mirror group, which focuses the echo generated by the object being irradiated by the output light to the second detector of the radar.

[0131] The above description is only a preferred embodiment of the present application, and only specifically describes the technical principles of the present application. These descriptions are only for explaining the principles of the present application and cannot be interpreted in any way as limiting the scope of protection of the present application. Based on the explanation here, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application, and other specific implementation methods of the present application that can be associated with by technicians in this field without creative work, should be included in the scope of protection of the present application.

Claims

1. A transmitting mirror assembly, characterized in that: The equivalent focal length of the transmitting mirror group in the horizontal direction is different from the equivalent focal length in the vertical direction, and the focal plane of the transmitting mirror group in the horizontal direction and the focal plane in the vertical direction coincide with each other.

2. The transmitting mirror assembly according to claim 1, characterized in that: The transmitting lens group comprises a first lens, a second lens, a third lens and a fourth lens with positive refractive power, which are arranged in sequence from the object plane to the image plane; wherein at least one refractive surface of the third lens is a cylindrical surface, at least one refractive surface of the fourth lens is a cylindrical surface, and the axis of the cylindrical surface in the third lens is arranged at an angle to the axis of the cylindrical surface in the fourth lens; The third lens, the first lens and the second lens form a first collimating lens group, the fourth lens, the first lens and the second lens form a second collimating lens group, the second collimating lens group and the first collimating lens group have different equivalent focal lengths, but their focal planes coincide.

3. The transmitting mirror assembly according to claim 2, characterized in that: The axis of the cylindrical surface in the third lens is perpendicular to the axis of the cylindrical surface in the fourth lens.

4. The transmitting mirror assembly according to claim 2, characterized in that: The first lens, the second lens, the third lens and the fourth lens satisfy the following relationship: 1.4 <n1、n4<2.1;1.8<n2、n3<2.1; Among them, n1 is the refractive index of the first lens when the wavelength is 900nm; n2 is the refractive index of the first lens when the wavelength is 900nm; n3 is the refractive index of the first lens when the wavelength is 900nm; n4 is the refractive index of the first lens when the wavelength is 900nm.

5. The transmitting mirror assembly according to claim 2, characterized in that: The first lens has negative refractive power, the object side surface is concave, and the image side surface is concave or convex; the second lens has positive refractive power, the object side surface is concave, and the image side surface is convex; the third lens has positive refractive power.

6. The transmitting mirror assembly according to claim 2, characterized in that: The transmitting lens group also includes an aperture, which is located between the third lens and the fourth lens.

7. The transmitting mirror assembly according to claim 2, characterized in that: The apertures of the first lens, the second lens and the third lens increase in sequence.

8. The transmitting mirror assembly according to any one of claims 1 to 7, characterized in that: The ratio of the horizontal focal length to the vertical focal length of the transmitting mirror assembly is greater than 1.

5.

9. A laser radar, characterized in that: The laser radar includes a transmitting module, a transmitting mirror group, a receiving mirror group and a receiving module which are arranged in sequence. The transmitting module is used to provide a detection beam. The transmitting mirror group is the transmitting mirror group described in any one of claims 1 to 8, which is used to collimate the detection beam. The receiving mirror group is used to receive an echo beam formed after the collimated detection beam is reflected by the detection object. The receiving module is used to receive and process the echo beam transmitted by the receiving mirror group.

10. The laser radar according to claim 9, characterized in that: The transmitting module comprises a plurality of transmitting units arranged in an array, and all the transmitting units are integrated on the same circuit board; And / or, the receiving module includes a plurality of receiving units arranged in an array, and all the receiving units are integrated on the same circuit board.

11. The laser radar according to claim 9, characterized in that: The emission module comprises a plurality of emission units arranged in an array, and all the emission units are integrated on the same circuit board; the emission units are vertical cavity surface emitting lasers.

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