Optical system and laser radar

Abstract

The invention relates to an optical system and a laser radar, the optical system comprises a light filtering member and at least one optical lens assembly, and the optical lens assembly is arranged on the image surface side of the light filtering member; the optical lens assembly comprises at least one optimization element, the optimization element is a lens with a mirror face on one side being an inclined face, and the product of the tangent slope of the light filtering part corresponding to the light path where the optimization element is located and the inclination angle slope of the inclined face is negative. The optical lens assembly can be arranged to be one or more of a transmitting assembly, a receiving assembly or other optical assemblies, the optimization element is arranged in the optical lens assembly, and the optimization element corresponds to the light filtering part in a matched mode; the optimized element is matched with other lenses, so that aberration such as spherical aberration, astigmatism and distortion generated by the lenses when light passes through the optical system can be reduced, the influence of a light filtering part is eliminated, the energy gathering quality of the optical system is improved, and the size and cost of the laser radar are reduced.

Description

Technical Field

[0001] The present disclosure relates to the technical field of optical systems, and in particular, to an optical system and a lidar. Background Art

[0002] Currently, in lidars, the lidar housing often uses a light-transmitting element with refractive power, which causes the divergence angle of the spot of the emitted light of the lidar to be large and uneven. Similarly, the received light reflected after irradiating an object is also affected by the lidar housing to form an aberration, ultimately resulting in inaccurate detection of the lidar. Summary of the Invention

[0003] In order to solve at least one of the above-mentioned technical problems, the present disclosure provides an optical system and a lidar.

[0004] According to some embodiments of the present disclosure, an optical system is provided. The optical system includes a filter element and at least one optical lens assembly. The optical lens assembly is disposed on the image plane side of the filter element. The optical lens assembly includes at least one optimization element, and the optimization element is a lens with one side mirror surface being an inclined surface. The product of the tangent slope of the filter element corresponding to the optical path where the optimization element is located and the inclination slope of the inclined surface is negative.

[0005] Based on the above solution, the optimization element can eliminate the aberration generated when light passes through the filter element, which is beneficial to improving the quality of energy convergence of the optical system.

[0006] In some possible implementation manners, the optical system further includes a transmitting assembly. The transmitting assembly includes a transmitting mirror group and a laser source. The transmitting mirror group is one of the optical lens assemblies. The transmitting mirror group is disposed on the propagation path of the emitted light beam of the laser source. The transmitting mirror group is used to collimate and optimize the optical path of the emitted light beam. The transmitting mirror group includes a collimating mirror group and at least one of the optimization elements.

[0007] In some possible implementation manners, the optical system further includes a receiving assembly. The receiving assembly includes a receiving mirror group and a detector. The receiving mirror group is one of the optical lens assemblies. The receiving mirror group is disposed on the propagation path of the received light beam of the detector. The receiving mirror group is used to condense and optimize the optical path of the received light beam. The receiving mirror group includes a condenser mirror group and at least one of the optimization elements.

[0008] Based on the above solution, optimization elements are respectively arranged in the transmitting assembly and the receiving assembly. The optimization element can eliminate the aberration generated when light passes through the filter element. The lidar can flexibly select and configure the transmitting assembly and / or the receiving assembly, which helps to reduce the volume of the lidar and the cost of the lidar.

[0009] In some possible embodiments, the transmitting assembly includes at least one of the laser sources, the receiving assembly includes at least one of the detectors, and the number of the detectors is less than or equal to the number of the laser sources.

[0010] Based on the above solution, it is possible to place multiple laser sources and multiple detectors in a lidar, thereby increasing the detection range of the lidar and further reducing the cost of the lidar.

[0011] In some possible embodiments, the transmitting assembly includes at least two of the laser sources, and the at least two laser sources are evenly distributed circumferentially along the optical axis of the transmitting mirror group.

[0012] Based on the above solution, the uniform distribution of the transmitting assembly circumferentially along the optical axis of the transmitting mirror group can make the spots of the transmitted light rays evenly distributed, so that the detection range of the lidar is evenly distributed, and further improve the accuracy of the lidar in detecting objects.

[0013] In some possible embodiments, the filter element is in an arc structure or a spherical structure, the refractive index of the filter element is greater than 1, and the thickness of the filter element is greater than or equal to 1 mm.

[0014] Based on the above solution, the filter element can smoothly transmit the light beam and has sufficient strength to protect the internal components of the lidar and ensure the safety of the lidar.

[0015] In some possible embodiments, the optical system includes two optical lens assemblies, which are the transmitting mirror group and the receiving mirror group respectively. The optical lenses included in the transmitting mirror group are the same as those of the receiving mirror group, and the transmitting mirror group and the receiving mirror group are axially symmetric about the optical axis of the filter element.

[0016] Based on the above solution, the transmitting mirror group and the receiving mirror group are the same and axially symmetric about the optical axis of the filter element, which can reduce the influence of the filter element on the transmitted light rays and received light rays of the lidar, thereby reducing the debugging difficulty of the transmitting mirror group and the receiving mirror group.

[0017] In some possible embodiments, the transmitting mirror group includes, in order from the object surface to the image surface along its optical axis: a first lens, the object surface of the first lens is convex, and the image surface of the first lens is concave; a second lens, the second lens is the optimization element, the object surface of the second lens is flat, and the image surface of the second lens is inclined; a third lens, the object surface of the third lens is a convex cylindrical surface, and the image surface of the third lens is flat; a fourth lens, the object surface of the fourth lens is convex, and the image surface of the fourth lens is convex; a fifth lens, the object surface of the fifth lens is convex, and the image surface of the fifth lens is flat.

[0018] Based on the above solution, the optimized element is selected as a lens with a flat object surface and an inclined image surface. Cooperating with other lenses can reduce aberrations such as spherical aberration, astigmatism, and distortion generated by each lens when light passes through the optical system, which is beneficial to reducing the influence brought by the filter element.

[0019] In some possible embodiments, the refractive index range of the first lens at a wavelength of 905 nm is 1.9 - 2.0; the refractive index range of the second lens at a wavelength of 905 nm is 1.5 - 1.6, and the range of the inclined angle of the inclined surface of the second lens is 0.16° - 1°; the refractive index range of the third lens at a wavelength of 905 nm is 1.5 - 1.6; the refractive index range of the fourth lens at a wavelength of 905 nm is 1.7 - 1.8; the refractive index range of the fifth lens at a wavelength of 905 nm is 1.9 - 2.0.

[0020] Based on the above solution, by limiting the diopter of each lens, it is beneficial to the collimation efficiency of the optical system of the lidar, reduces the energy consumption, improves the quality of energy convergence, so that the light spot is clearer, and further improves the detection accuracy of the lidar.

[0021] In some possible embodiments, the emitting lens group includes, in sequence along its optical axis direction from the object surface to the image surface: a sixth lens, the object surface of the sixth lens is convex, and the image surface of the sixth lens is concave; a seventh lens, the seventh lens is the optimized element, the object surface of the seventh lens is cylindrical, and the image surface of the seventh lens is inclined; an eighth lens, the object surface of the eighth lens is concave, and the image surface of the eighth lens is concave; a ninth lens, the object surface of the ninth lens is convex, and the image surface of the ninth lens is convex.

[0022] Based on the above solution, the optimized element is selected as a lens with a cylindrical object surface and an inclined image surface. Cooperating with other lenses can reduce aberrations such as spherical aberration, astigmatism, and distortion generated by each lens when light passes through the optical system, which is beneficial to reducing the influence brought by the filter element.

[0023] In some possible embodiments, the refractive index range of the sixth lens at a wavelength of 905 nm is 1.9 - 2.0; the refractive index range of the seventh lens at a wavelength of 905 nm is 1.5 - 1.6, and the range of the inclined angle of the inclined surface of the seventh lens is 0.16° - 1°; the refractive index range of the eighth lens at a wavelength of 905 nm is 1.5 - 1.6; the refractive index range of the ninth lens at a wavelength of 905 nm is 1.7 - 1.9.

[0024] Based on the above solution, by limiting the diopter of each lens, it is beneficial to the collimation efficiency of the optical system of the lidar, reduces energy loss, improves the quality of energy convergence, makes the light spot clearer, and thus improves the detection accuracy of the lidar.

[0025] In some other embodiments of the present disclosure, a lidar is provided, including an optical system according to any one of the above embodiments.

[0026] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and do not limit the present disclosure.

[0027] Other features and aspects of the present disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present specification or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present specification. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 A schematic diagram showing an optical system according to an embodiment of the present disclosure;

[0030] Figure 2 A schematic diagram showing the emission optical path of an optical system without an optimization element according to an embodiment of the present disclosure;

[0031] Figure 3 A schematic diagram showing the emission optical path of an optical system with an optimization element according to an embodiment of the present disclosure;

[0032] Figure 4 A schematic diagram showing the emission optical path of an optical system with another optimization element according to an embodiment of the present disclosure;

[0033] Figure 5 A schematic diagram showing an optical system according to a specific solution of an embodiment of the present disclosure;

[0034] Figure 6 A schematic diagram showing an optical system according to another specific solution of an embodiment of the present disclosure.

[0035] In the figure:

[0036] 1 - Filter element; 2 - Laser source; 3 - Collimating lens group; 4 - Condensing lens group; 5 - Optimization element; 6 - First lens; 7 - Second lens; 8 - Third lens; 9 - Fourth lens; 10 - Fifth lens; 11 - Sixth lens; 12 - Seventh lens; 13 - Eighth lens; 14 - Ninth lens. Detailed implementation mode

[0037] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this specification. Obviously, the described embodiments are only a part of the embodiments of this specification, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this specification without creative efforts shall fall within the scope of protection of the present invention.

[0038] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned accompanying drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or server including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0039] The various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the drawings denote elements having the same or similar functions. Although various aspects of the embodiments are shown in the drawings, the drawings do not have to be drawn to scale unless otherwise specified.

[0040] The special term "exemplary" herein means "serving as an example, embodiment or illustrative". Any embodiment described as "exemplary" here does not have to be construed as superior or better than other embodiments.

[0041] The term "and / or" in this article is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the term "at least one" in this article means any one of a plurality or any combination of at least two of a plurality. For example, including at least one of A, B, and C can represent including any one or more elements selected from the set composed of A, B, and C.

[0042] In addition, for a better illustration of the present disclosure, numerous specific details are given in the following specific implementation manners. Those skilled in the art should understand that the present disclosure can also be implemented without certain specific details. In some instances, methods, means, elements, and circuits well-known to those skilled in the art are not described in detail so as to highlight the gist of the present disclosure.

[0043] For ease of understanding of the present disclosure, some technical terms appearing in the present disclosure are explained or defined below:

[0044] Laser radar, whose English name is Laser Radar, is a radar system that detects the position, speed, and other characteristic quantities of a target by emitting laser beams. Its working principle is to emit a detection signal (laser beam) to the target, and then compare the received signal (target echo) reflected from the target with the emitted signal. After appropriate processing, relevant information about the target can be obtained, such as parameters like target distance, azimuth, altitude, speed, attitude, and even shape, so as to detect, track, and identify the target.

[0045] A collimating mirror is used to maintain the collimation of the light speed between a laser resonator and a focusing optical element in a light beam transmission system. Its principle is to make the divergent incident light become parallel light when it exits by using a convex lens or the like.

[0046] A light spot refers to a laser light spot, which is the distribution pattern of a laser beam in space. After the output of a laser, the laser beam will be focused to form a small and bright light spot. The shape of the laser light spot can be circular, elliptical, or other shapes, depending on the output mode of the laser and the interference and diffraction effects of lenses or other optical elements. The shape and characteristics of the light spot will change with the change of the propagation distance.

[0047] LED is the abbreviation of light-emitting diode, that is, a light-emitting diode, which is a commonly used light-emitting device that emits light by the recombination of electrons and holes.

[0048] In addition, without special instructions, some elements or devices appearing in the embodiments of the present disclosure should be understood in a broad sense. For example, the collimating mirror, one of the optical elements mentioned in the present disclosure, should refer to a device that can make the divergent incident light become parallel light when it exits. The collimating mirror can be a single-piece lens or a lens group composed of multiple lenses; similarly, the focusing mirror, one of the optical elements mentioned in the present disclosure, can be a single-piece lens or a lens group composed of multiple lenses.

[0049] Currently, in lidar, the radar housing often uses a light-transmitting element with refractive power, that is, a filter element, such as a spherical shell, a hemispherical shell, a hemisphere, a hollow cylinder, etc. The filter element with refractive power will affect the light propagation path of the lidar. For example, it will cause the spot divergence angle of the emitted light of the lidar to be large and uneven, and the received light reflected after irradiating an object will also be affected by the filter element to form aberration, ultimately resulting in inaccurate detection of the lidar.

[0050] In the related art, the method of making the optical axis of the transmitting component coincide with the optical axis of the filter element is often adopted to reduce the influence of the filter element on imaging. Similarly, the optical axis of the receiving component also needs to coincide with the optical axis of the filter element. Then, the number of transmitting components and receiving components wrapped or covered by a single filter element is limited, resulting in a small detection range of the lidar; if multiple groups of transmitting components and receiving components are to be set, the corresponding number of filter elements needs to be set, which will increase the cost of the lidar while solving the detection range problem.

[0051] To solve the above technical problems, please refer to Figure 1 , in the embodiments of the present disclosure, an optical system is provided. The optical system includes a filter element 1 and at least one optical lens assembly. The optical lens assembly is arranged on the image plane side of the filter element 1; the optical lens assembly includes at least one optimization element 5. The optimization element 5 is a lens with an inclined surface on one side. The product of the tangent slope of the filter element 1 corresponding to the optical path where the optimization element 5 is located and the inclination slope of the inclined surface is negative. Based on the above solution, the optimization element 5 can eliminate the aberration generated when the light passes through the filter element 1, which is beneficial to improving the quality of energy convergence of the optical system.

[0052] In a further embodiment, the optical system further includes a transmitting component. The transmitting component includes a transmitting lens group and a laser source 2. The transmitting lens group is an optical lens assembly. The transmitting lens group is arranged on the propagation path of the emitted light beam of the laser source 2. The transmitting lens group is used to collimate and optimize the optical path of the emitted light beam. The transmitting lens group includes a collimating lens group 3 and at least one optimization element 5.

[0053] In a further embodiment, the optical system further includes a receiving component. The receiving component includes a receiving lens group and a detector. The receiving lens group is an optical lens assembly. The receiving lens group is arranged on the propagation path of the received light beam of the detector. The receiving lens group is used to condense and optimize the optical path of the received light beam. The receiving lens group includes a condenser lens group 4 and at least one optimization element 5.

[0054] It should be noted that the embodiments of the present disclosure do not limit the number of optical lens assemblies. In an optical system, there may be only one optical lens assembly, and the optical lens assembly may be a transmitting lens group, a receiving lens group or other optical function lens groups; there may be multiple optical lens assemblies, for example, two optical lens assemblies, namely a transmitting lens group and a receiving lens group.

[0055] It should be understood that the embodiments of the present disclosure do not limit that both the transmitting mirror group and / or the receiving mirror group in the lidar are the above-mentioned optical lens assemblies containing the optimization element 5. In some possible implementation manners, the lidar includes a plurality of transmitting mirror groups and a plurality of receiving mirror groups. The transmitting mirror group and / or the receiving mirror group can be partially selected and configured as the optical lens assembly containing the optimization element 5, or all can be selected and configured as the optical lens assembly containing the optimization element 5.

[0056] In an embodiment of the present disclosure, please refer to Figure 1 , the optical system includes a filter element 1 and two optical lens assemblies. The two optical lens assemblies are respectively a transmitting assembly and a receiving assembly. The transmitting assembly and the receiving assembly are arranged on the image plane side of the filter element 1, and the transmitting assembly and the receiving assembly are distributed on both sides of the symmetry plane of the filter element 1; the transmitting assembly includes a laser source 2 and a transmitting mirror group. The transmitting mirror group is arranged on the propagation path of the emission beam of the laser source 2. The transmitting mirror group is used to collimate the emission beam and optimize the optical path. The transmitting mirror group includes a collimating mirror group 3 and at least one optimization element 5; the receiving assembly includes a detector and a receiving mirror group. The receiving mirror group is arranged on the propagation path of the received beam of the detector. The receiving mirror group is used to condense the received beam and optimize the optical path. The receiving mirror group includes a condenser mirror group 4 and at least one optimization element 5; the optimization element 5 is a lens with one side mirror surface being an inclined surface. The product of the tangent slope of the filter element 1 corresponding to the optical path where the optimization element 5 is located and the inclination slope of the inclined surface is negative. Based on the above configuration, the transmitting assembly and the receiving assembly are respectively arranged on both sides of the symmetry plane of the filter element 1, and the optimization element 5 is respectively arranged in the transmitting assembly and the receiving assembly. The optimization element 5 can eliminate the aberration generated when the light passes through the filter element 1. Since the transmitting assembly and the receiving assembly are not concentric and coaxial with the filter element 1, that is to say, more optical system components can be placed within the wrapping space of one filter element 1, and the placement position of the optical system is more flexible and variable, which can indirectly reduce the overall volume of the lidar, and further reduce the cost of the lidar.

[0057] In the embodiments of the present disclosure, the mirror group should be understood in a broad sense. The mirror group can be understood as a group of lenses or wafers that achieve a certain specific effect on light. That is to say, the mirror group is not limited to including multiple optical lenses. For example, the collimating mirror group 3 can be a mirror group system composed of multiple optical lenses, or can only include one collimating mirror; the condenser mirror group 4 can be a mirror group system composed of multiple optical lenses, or can only include one condenser mirror. In addition, the mirror group can also be understood as a special lens formed by aggregating multiple different optical lenses.

[0058] In the embodiments of the present disclosure, the material of the optical lens is not limited. That is to say, the materials of the filter element 1, the transmitting mirror group, the receiving mirror group, and the optimization element 5 can be glass, plastic, glass-plastic hybrid material, or other types of light-transmitting materials.

[0059] In an embodiment of the present disclosure, the filter element 1 has an arc-shaped structure or a spherical structure. The refractive index of the filter element 1 is greater than 1, and the thickness of the filter element 1 is greater than or equal to 1 mm. Based on the above configuration, the filter element 1 can smoothly transmit the light beam and has a sufficient strength, and as a radar radome, it can protect the internal components of the lidar and ensure the safety of the lidar.

[0060] In an embodiment of the present disclosure, one filter element 1 corresponds to a pair of transmitting components and receiving components, and neither the transmitting components nor the receiving components are concentric and coaxial with the filter element 1, that is, the transmitting mirror group is deflected and eccentric relative to the filter element 1, and the receiving mirror group is deflected and eccentric relative to the filter element 1. Therefore, the filter element 1 with refractive power will respectively affect the transmitted light of the transmitting components and the received light of the receiving components. Please refer to Figure 2 , the transmitting components have two laser sources 2. After passing through the transmitting mirror group and the filter element 1, the two laser sources 2 respectively form two light spots. As can be seen from the figure, the shapes of the two light spots are asymmetrical and have a large divergence angle, that is, the aberration of the light spots finally formed by the two laser sources 2 is large. Among them, the aberration of the left light spot is significantly greater than that of the right light spot. That is to say, the greater the distance between the light emitted by the laser source 2 and the optical axis of the filter element 1 and the greater the angle of the light emitted by the laser source 2 relative to the optical axis of the filter element 1, the greater the influence of the filter element 1 on the propagation of the light and the greater the aberration generated. It should be understood that during the propagation of the received light of the lidar, the influence effect of the filter element 1 on the propagation of the received light is the same but in the opposite direction.

[0061] In an embodiment of the present disclosure, the purpose of respectively arranging the optimization elements 5 in the transmitting mirror group and the receiving mirror group is to reduce the influence of the filter element 1 on the propagation of the light. Please refer to Figure 3, the optimization element 5 in the transmitting mirror group and the optimization element 5 in the receiving mirror group are placed in opposite directions. Among them, in the propagation path of the transmitted light of the lidar, for the part of the transmitted light passing through the left half area of the filter element 1, the filter element 1 will deflect and diverge the transmitted light to the left. Since there are two laser sources 2 in the transmitting assembly, after the two laser sources 2 pass through the transmitting mirror group and the filter element 1, two light spots are respectively formed. The laser source 2 on the right side in the transmitting assembly is collimated by the transmitting mirror group and finally emits a collimated light beam to the image plane of the filter element 1 at an angle deflected to the left. In order to achieve the effect of reducing the influence of the filter element 1 on the light propagation, the optimization element 5 in the transmitting mirror group needs to deflect and diverge the transmitted light to the right, so as to offset the deflection and divergence effect of the filter element 1 on the transmitted light. Then, the optimization element 5 of the transmitting mirror group should be a lens with a smaller thickness on the left side than on the right side. Similarly, the optimization element 5 of the receiving mirror group should be a lens with a smaller thickness on the right side than on the left side. Therefore, the thickness of the side of the optimization element 5 close to the optical axis of the filter element 1 is smaller than the thickness of the side of the optimization element 5 far from the optical axis of the filter element 1, and only then can the optimization element 5 effectively reduce the influence of the filter element 1 on the light propagation.

[0062] The embodiments of the present disclosure do not limit the specific structure and parameters of the optimization element 5. Based on the above embodiments, the optimization element 5 can be a wedge mirror, or a wedge surface with an inclination angle on one of the same optical surfaces, or other optical elements that meet the above conditions. It can be understood that the specific structure and parameters of the optimization element 5 should be selected according to the filter element 1 and the transmitting mirror group and the receiving mirror group.

[0063] In some embodiments of the present disclosure, the optimization element 5 is a lens with one side mirror surface being an inclined surface, and the product of the tangent slope of the filter element 1 corresponding to the optical path where the optimization element 5 is located and the inclination slope of the inclined surface is negative. For example, please refer to Figure 3 - Figure 4 , in the propagation path of the transmitted light of the lidar, the image plane of the optimization element 5 is an inclined surface, and the corresponding filter element 1 is the left half area. Then, the inclination slope of the inclined surface is negative, and the tangent slope of the filter element 1 is positive, that is, the product of the tangent slope of the filter element 1 and the inclination slope of the inclined surface is negative. Based on the above configuration, setting one side mirror surface of the optimization element 5 as an inclined surface can reduce the matching difficulty of the optimization element 5 and reduce the time for debugging the lens group. When matching the optimization element 5 and debugging the light of the lidar, only the non-inclined surface side of the optimization element 5 needs to be replaced.

[0064] In some possible embodiments, the optimization element 5 is composed of two lenses stacked on top of each other. The media of the two lenses are the same, and there is no gap between the two lenses. The lower lens serves as a fixed lens, with its object surface being a plane and its image surface being an inclined plane. The upper lens serves as a replaceable lens, with its image surface being a plane, and the shape of its object surface is not limited. When debugging the light of the lidar, by replacing the upper replaceable lens and selecting replaceable lenses with different-shaped object surfaces, the light spots formed by the emitted light of the lidar are respectively tested until the light of the lidar meets the detection requirements. Based on the operation steps of this embodiment, rapid and accurate debugging can be achieved.

[0065] It should be understood that the inclined plane of the optimization element 5 in the embodiments of the present disclosure is not limited to a plane. That is to say, the inclined plane of the optimization element 5 can be a plane, for example Figure 3 the optimization element 5 in, the inclined plane of the optimization element 5 can also be a curved surface, for example Figure 4 the optimization element 5 in, or the inclined plane of the optimization element 5 can also be selected as an arc surface, an elliptical arc surface or other special curved surfaces, etc.

[0066] In the embodiments of the present disclosure, the number of emitted light rays and the number of received light rays of the lidar are not limited to being the same. That is to say, the lidar can include only one emitted light ray and one received light ray, the lidar can also include multiple emitted light rays and one received light ray, or the lidar can include multiple emitted light rays and multiple received light rays. Therefore, the emission component includes at least one laser source 2, and the reception component includes at least one detector. It should be noted that according to some of the above embodiments, the light rays emitted by some of the laser sources 2 will deviate from the optical axis of the filter element 1 after passing through the emission mirror group and the filter element 1, and finally form the emitted light rays. When the deviation angle of one emitted light ray is large enough, the reflected light ray of the emitted light ray after irradiating an object may not be able to pass through the filter element 1 and the reception mirror group, and thus cannot be received and sensed by the detector. Therefore, in the embodiments of the present disclosure, the number of detectors is less than or equal to the number of laser sources 2, and the number of laser sources 2 is more than one. Based on the above configuration, one filter element 1 can emit multiple detection light rays to form multiple detection ranges. Compared with the solution in the related art where the emission component and the filter element 1 are coaxial, when achieving the same number or the same area of detection ranges using the solution of this embodiment, the number of filter elements 1 required is less. That is to say, the cost of the corresponding filter element 1 can be saved and the volume of the space occupied by the corresponding filter element 1 can be reduced.

[0067] In the embodiments of the present disclosure, please refer to Figure 2 - Figure 4, in order to increase the detection range of the lidar, the emitted light rays of the lidar are more than two beams, and the corresponding emission component should include at least two laser sources 2. When the lidar has multiple emission light rays, multiple emission spots will be formed. At this time, it is necessary to avoid the intersection between the spots and the uneven distance between the spots. Therefore, it is necessary to reasonably set the distribution positions of the laser sources 2.

[0068] In some embodiments of the present disclosure, the emission component includes an even number of laser sources 2, and the laser sources 2 are symmetrically distributed on both sides of the optical axis of the emission mirror group. Based on this configuration, the emission spots formed by the emitted light rays of the lidar will be arranged in a straight line. This solution is adapted to the lidar with the filter 1 being an arc-shaped structure, and the distance between the formed spots is uniform, which can ensure the detection accuracy of the lidar while increasing the detection range of the lidar.

[0069] In some other embodiments of the present disclosure, the emission component includes more than two laser sources 2, and the more than two laser sources 2 are evenly distributed along the circumferential direction of the optical axis of the emission mirror group. Based on this configuration, the emission spots formed by the emitted light rays of the lidar will be arranged in a loop. This solution is adapted to the lidar with the filter 1 being a spherical shell structure, and the distance between the formed spots is uniform, which can ensure the detection accuracy of the lidar while increasing the detection range of the lidar. Further, on the basis of the above solution, an additional laser source 2 can be provided on the optical axis of the emission mirror group, so that the emission spots formed by the emitted light rays of the lidar are circularly distributed, improving the spot density and further improving the detection accuracy of the lidar.

[0070] In some possible embodiments, the optical system further includes a control module. The control module is electrically connected to multiple laser sources 2 in the emission component. The control module is used to selectively control the lighting and extinguishing of each laser source 2. Based on the control module, multiple laser sources 2 can be preset in the optical system, and different combinations of laser sources 2 can be selected successively through the control module until the lidar meets the detection requirements. In addition, in the above embodiments, the optical system can further be provided with a transmission module. The transmission module is used to adjust the positions of each laser source 2, cooperate with the control module, and assist in selecting the optimal position of the laser source 2, thereby simplifying the debugging process of the lidar and reducing the design time of the lidar.

[0071] In the embodiments of the present disclosure, the specific type of the laser source 2 is not limited. It should be understood that all laser sources 2 that can be used for lidar can be applied to the solutions of the embodiments of the present disclosure. That is to say, the type of the laser source 2 can be a laser diode, a fiber light source, a solid-state laser, an LED light source, etc. On the other hand, the embodiments of the present disclosure also do not limit the specific form of the light beam emitted by the laser source 2. For example, in the specific implementation process, the laser source 2 can have a polarization state or no polarization state.

[0072] In some embodiments of the present disclosure, in order to further reduce the debugging difficulty of the lidar, based on the principle of light reflection, the transmitting mirror group and the receiving mirror group are set to be exactly the same, and the transmitting mirror group and the receiving mirror group are axisymmetric with respect to the optical axis of the filter 1. Based on the above solution, the transmitting mirror group and the receiving mirror group are the same. Specifically, the optical lenses included in the transmitting mirror group are the same as those of the receiving mirror group, and each optical lens corresponds to each other and is symmetrically distributed on both sides of the optical axis. The light emitted by the transmitting component irradiates on the object surface and then passes through the receiving component after reflection. The light passes through the filter 1 twice during the propagation process, and the penetration points of passing through the filter 1 are also axisymmetric with respect to the optical axis of the filter 1. That is to say, the deflection directions of the filter 1 for the light twice are opposite, that is, the effects of the filter 1 on the light twice cancel each other out. Therefore, the above solution can reduce the influence of the filter 1 on the emitted light and the received light of the lidar. When designing the optical path of the lidar and selecting and configuring the optical system components (optical elements), only the composition of the transmitting component needs to be considered, and according to the emission spot finally formed by the light emitted by the transmitting component, it can be determined whether the lidar meets the detection requirements. The receiving component only needs to be set according to the selection and configuration of the transmitting component, thereby reducing the debugging difficulty of the transmitting mirror group and the receiving mirror group, shortening the debugging time of the lidar, and improving the debugging efficiency of the lidar.

[0073] It should be understood that the corresponding solutions among the above multiple embodiments can be combined with each other to meet the detection requirements of different types and specifications of lidars. In order to more clearly illustrate an optical system according to an embodiment of the present disclosure, the present disclosure will provide two specific embodiment solutions for readers to understand.

[0074] In a specific embodiment, please refer to Figure 5, the optical system includes a transmitting component, a receiving component, and a filter element 1 with refractive power. The transmitting component and the receiving component are arranged on the image plane side of the filter element 1. The transmitting component includes a laser source 2 and a transmitting lens group, and the receiving component includes a detector and a receiving lens group. The optical lenses included in the transmitting lens group are the same as those of the receiving lens group, and the transmitting lens group and the receiving lens group are axisymmetric about the optical axis of the filter element 1. Along the optical axis direction of the transmitting lens group, from the object plane to the image plane, it successively includes: a first lens 6 with refractive power, the object plane of the first lens 6 is convex, and the image plane of the first lens 6 is concave; a second lens 7 with refractive power, the second lens 7 is an optimization element 5, the object plane of the second lens 7 is flat, and the image plane of the second lens 7 is inclined; a third lens 8 with refractive power, the object plane of the third lens 8 is a convex cylinder, and the image plane of the third lens 8 is flat; a fourth lens 9 with refractive power, the object plane of the fourth lens 9 is convex, and the image plane of the fourth lens 9 is convex; a fifth lens 10 with refractive power, the object plane of the fifth lens 10 is convex, and the image plane of the fifth lens 10 is flat. Similarly, along the optical axis direction of the receiving lens group, from the object plane to the image plane, it successively includes: the above-mentioned first lens 6, the above-mentioned second lens 7, the above-mentioned third lens 8, the above-mentioned fourth lens 9, and the above-mentioned fifth lens 10.

[0075] In this embodiment, the optimization element 5 is selected as a lens with a flat object plane and an inclined image plane. Cooperating with other lenses can reduce aberration such as spherical aberration, astigmatism, and distortion generated by each lens when light passes through the optical system, which is beneficial to reducing the influence brought by the filter element 1. In order to further improve the convergence quality of light energy, the parameters of each optical element in this embodiment are limited as follows:

[0076] The refractive index of the filter element 1 is greater than 1, and the thickness of the filter element 1 is greater than or equal to 1 mm;

[0077] The refractive index range of the first lens 6 at a wavelength of 905 nm is 1.9 - 2.0;

[0078] The refractive index range of the second lens 7 at a wavelength of 905 nm is 1.5 - 1.6, and the range of the inclination angle of the inclined plane of the second lens 7 is 0.16° - 1°. The above-mentioned inclination angle of the inclined plane refers to the angle between the inclined plane and the horizontal plane;

[0079] The refractive index range of the third lens 8 at a wavelength of 905 nm is 1.5 - 1.6;

[0080] The refractive index range of the fourth lens 9 at a wavelength of 905 nm is 1.7 - 1.8;

[0081] The refractive index range of the fifth lens 10 at a wavelength of 905 nm is 1.9 - 2.0.

[0082] By defining the diopter of each lens, it is beneficial to the collimation efficiency of the optical system of the lidar, reduce energy loss, improve the quality of energy convergence, thus making the light spot clearer, and further improving the detection accuracy of the lidar.

[0083] In another specific embodiment, please refer to Figure 6 , the optical system includes a transmitting component, a receiving component, and a filter 1 with refractive power. The transmitting component and the receiving component are arranged on the image plane side of the filter 1. The transmitting component includes a laser source 2 and a transmitting lens group. The receiving component includes a detector and a receiving lens group. The optical lenses included in the transmitting lens group are the same as those of the receiving lens group, and the transmitting lens group and the receiving lens group are axisymmetric about the optical axis of the filter 1. The transmitting lens group includes, in order from the object plane to the image plane along its optical axis: a sixth lens 11 with refractive power, the object plane of the sixth lens 11 is convex, and the image plane of the sixth lens 11 is concave; a seventh lens 12 with refractive power, the seventh lens 12 is an optimization element 5, the object plane of the seventh lens 12 is cylindrical, and the image plane of the seventh lens 12 is inclined; an eighth lens 13 with refractive power, the object plane of the eighth lens 13 is concave, and the image plane of the eighth lens 13 is concave; a ninth lens 14 with refractive power, the object plane of the ninth lens 14 is convex, and the image plane of the ninth lens 14 is convex. Similarly, the receiving lens group includes, in order from the object plane to the image plane along its optical axis: the above-mentioned sixth lens 11, the above-mentioned seventh lens 12, the above-mentioned eighth lens 13, and the above-mentioned ninth lens 14.

[0084] In this embodiment, the optimization element 5 is selected as a lens with a cylindrical object plane and an inclined image plane. Cooperating with other lenses can reduce aberrations such as spherical aberration, astigmatism, and distortion generated by each lens when light passes through the optical system, which is beneficial to reducing the influence brought by the filter 1. In order to further improve the convergence quality of light energy, the parameters of each optical element in this embodiment are defined as:

[0085] The refractive index of the filter 1 is greater than 1, and the thickness of the filter 1 is greater than or equal to 1 mm;

[0086] The refractive index range of the sixth lens 11 at a wavelength of 905 nm is 1.9 - 2.0;

[0087] The refractive index range of the seventh lens 12 at a wavelength of 905 nm is 1.5 - 1.6, and the range of the inclined angle of the inclined plane of the seventh lens 12 is 0.16° - 1°. The above-mentioned inclined angle of the inclined plane refers to the angle between the inclined plane and the horizontal plane;

[0088] The refractive index range of the eighth lens 13 at a wavelength of 905 nm is 1.5 - 1.6;

[0089] The refractive index range of the ninth lens 14 at a wavelength of 905 nm is 1.7 - 1.9.

[0090] By defining the diopter of each lens, it is beneficial to the collimation efficiency of the optical system of the lidar, reduces the energy loss, improves the quality of energy convergence, thus making the light spot clearer, and further improving the detection accuracy of the lidar.

[0091] In some other embodiments of the present disclosure, a lidar is further provided, and the lidar includes an optical system described in any one of the above embodiments. The specific type of the lidar in the embodiments of the present disclosure is not limited. The lidar can be a vehicle-mounted lidar, a road lidar, or applied to other scenarios or other devices. In addition, in the lidar, the above optical system can be used as an independent component system or can be split into multiple modules.

[0092] The various embodiments of the present disclosure have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, the practical application, or the improvement of the technology in the market, or to enable other ordinary skill in the art in the technical field to understand the embodiments disclosed herein.

Claims

1. An optical system, characterized in that: The optical system includes a filter element (1) and at least one optical lens assembly, and the optical lens assembly is arranged on the image plane side of the filter element (1); The optical lens assembly includes at least one optimization element (5), the optimization element (5) is a lens with one side mirror surface being an inclined surface, and the product of the tangent slope of the filter element (1) corresponding to the optical path where the optimization element (5) is located and the inclination slope of the inclined surface is negative.

2. The optical system according to claim 1, wherein: The optical system further includes a transmitting assembly, the transmitting assembly includes a transmitting mirror group and a laser source (2), the transmitting mirror group is one of the optical lens assemblies, the transmitting mirror group is arranged on the propagation path of the transmitting beam of the laser source (2), the transmitting mirror group is used for collimating and optimizing the optical path of the transmitting beam, and the transmitting mirror group includes a collimating mirror group (3) and at least one of the optimization elements (5).

3. The optical system according to claim 1, characterized in that: The optical system further includes a receiving assembly, the receiving assembly includes a receiving mirror group and a detector, the receiving mirror group is one of the optical lens assemblies, the receiving mirror group is arranged on the propagation path of the receiving beam of the detector, the receiving mirror group is used for condensing and optimizing the optical path of the receiving beam, and the receiving mirror group includes a condenser lens group (4) and at least one of the optimization elements (5).

4. The optical system according to claim 1, wherein: The filter element (1) is an arc structure or a spherical structure, the refractive index of the filter element (1) is greater than 1, and the thickness of the filter element (1) is greater than or equal to 1 mm.

5. The optical system according to claim 1, characterized in that: The optical system includes two of the optical lens assemblies, the two optical lens assemblies are respectively a transmitting mirror group and a receiving mirror group, the optical lenses included in the transmitting mirror group are the same as those of the receiving mirror group, and the transmitting mirror group and the receiving mirror group are axially symmetric about the optical axis of the filter element (1).

6. The optical system according to claim 5, wherein: The optical lens assembly sequentially includes, from the object plane to the image plane along its optical axis direction: A first lens (6), the object plane of the first lens (6) is a convex surface, and the image plane of the first lens (6) is a concave surface; A second lens (7), the second lens (7) is the optimization element (5), the object plane of the second lens (7) is a plane, and the image plane of the second lens (7) is an inclined surface; A third lens (8), the object plane of the third lens (8) is a convex cylindrical surface, and the image plane of the third lens (8) is a plane; A fourth lens (9), the object plane of the fourth lens (9) is a convex surface, and the image plane of the fourth lens (9) is a convex surface; A fifth lens (10), the object plane of the fifth lens (10) is a convex surface, and the image plane of the fifth lens (10) is a plane.

7. The optical system according to claim 6, wherein: The refractive index range of the first lens (6) at a wavelength of 905 nm is 1.9 - 2.0; The refractive index range of the second lens (7) at a wavelength of 905 nm is 1.5 - 1.6, and the range of the inclined surface inclination angle of the second lens (7) is 0.16° - 1°; The refractive index range of the third lens (8) at a wavelength of 905 nm is 1.5 - 1.6; The refractive index range of the fourth lens (9) at a wavelength of 905 nm is 1.7 - 1.8; The refractive index range of the fifth lens (10) at a wavelength of 905 nm is 1.9 to 2.

0.

8. The optical system according to claim 5, wherein: The optical lens assembly sequentially includes, from the object surface to the image surface along its optical axis direction: A sixth lens (11), the object surface of the sixth lens (11) is convex, and the image surface of the sixth lens (11) is concave; A seventh lens (12), the seventh lens (12) is the optimization element (5), the object surface of the seventh lens (12) is cylindrical, and the image surface of the seventh lens (12) is inclined; An eighth lens (13), the object surface of the eighth lens (13) is concave, and the image surface of the eighth lens (13) is concave; A ninth lens (14), the object surface of the ninth lens (14) is convex, and the image surface of the ninth lens (14) is convex.

9. The optical system according to claim 8, wherein: The refractive index range of the sixth lens (11) at a wavelength of 905 nm is 1.9 to 2.0; The refractive index range of the seventh lens (12) at a wavelength of 905 nm is 1.5 to 1.6, and the range of the inclination angle of the inclined surface of the seventh lens (12) is 0.16° to 1°; The refractive index range of the eighth lens (13) at a wavelength of 905 nm is 1.5 to 1.6; The refractive index range of the ninth lens (14) at a wavelength of 905 nm is 1.7 to 1.

9.

10. A lidar, characterized in that, An optical system according to any one of claims 1-9.

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