WO2024002107A1

WO2024002107A1 - Laser receiving system, lidar, lens assembly, electronic device and vehicle

Info

Publication number: WO2024002107A1
Application number: PCT/CN2023/102943
Authority: WO
Inventors: 贾远林; 徐运强; 周勇; 王晓芳; 陈洪福; 肖流长
Original assignee: 华为技术有限公司
Priority date: 2022-06-30
Filing date: 2023-06-27
Publication date: 2024-01-04
Also published as: CN117368942A

Abstract

A laser receiving system (100), a lidar (1000), a lens assembly, an electronic device and a vehicle (2000). The laser receiving system (100) comprises a detector (120) and a receiving lens group (110). The receiving lens group (110) comprises a non-rotationally symmetric lens group (111) and a rotationally symmetric lens group (112), wherein the rotationally symmetric lens group (112) comprises at least three rotationally symmetric lenses (1121); and the non-rotationally symmetric lens group (111) comprises at least one non-rotationally symmetric lens (1111), the angular magnification of the non-rotationally symmetric lens group (111) in a sagittal direction is greater than 1, and the non-rotationally symmetric lens group (111) is used for making the receiving lens group (110) satisfy a conditional expression: EFLx/EFLy ≥ 1.2. By means of such arrangements, the size of a light spot in the sagittal direction can be increased, such that the detector (120) avoids damage caused by too concentrated energy, and the assembly difficulty of the laser receiving system (100) can be reduced.

Description

Laser receiving systems, lidar, lens components, electronic equipment and vehicles

This application requests the priority of the Chinese patent application filed with the China Patent Office on June 30, 2022, with application number 202210762874.5 and the application name "Laser receiving system, lidar, lens assembly, electronic equipment and vehicle", and its entire contents incorporated herein by reference.

Technical field

Embodiments of the present application relate to the technical field of lidar, and in particular to a laser receiving system, lidar, lens assembly, electronic equipment and vehicle.

Background technique

Lidar is a radar system that emits a laser beam to detect the position, speed and other characteristics of the target to be measured. Among them, the laser transmitting system of the lidar emits laser to the target to be measured with a predetermined power. The laser diffusely reflects after encountering the target to be measured and is received by the laser receiving system of the lidar.

In related technology, the laser receiving system mainly includes a rotationally symmetrical mirror group and a detector. The rotationally symmetrical mirror group is located between the target to be measured and the detector. The rotationally symmetrical mirror group is used to focus the diffusely reflected laser onto the detector, so as to A light spot forms on the detector.

However, the above-mentioned detectors are easily damaged, and in addition, the laser receiving system is difficult to assemble.

Contents of the invention

Embodiments of the present application provide a laser receiving system, lidar, lens assembly, electronic equipment and vehicle, which solve the problem that the detector is easily damaged and the laser receiving system is difficult to assemble.

A first aspect of this application provides a laser receiving system, which at least includes: a receiving lens group and a detector that cooperates with the receiving lens group. The detector is used to receive the laser light transmitted through the receiving lens group to form an image on the detection surface of the detector. Along the optical axis direction from the object side to the image side, the receiving lens group includes a non-rotationally symmetric lens group and a rotationally symmetric lens group. The rotationally symmetric lens group includes at least three rotationally symmetric lenses. The non-rotationally symmetrical lens group includes at least one non-rotationally symmetrical lens. The non-rotationally symmetric lens group is used to make the receiving lens group satisfy the conditional expression: EFLx/EFLy≥1.2, where EFLx is the focal length of the receiving lens group in the sagittal direction, and EFLy is the receiving lens group in the sagittal direction. Focal length in the meridian direction. The angular magnification of the non-rotationally symmetric lens group in the sagittal direction is greater than 1.

The laser receiving system in the embodiment of the present application includes a receiving lens group and a detector. The laser light passing through the receiving lens group can be imaged on the detection surface of the detector, so that a light spot appears on the detection surface of the detector. Since the power of the asymmetric lens is inconsistent in the meridional and sagittal directions, the asymmetric lens group makes the focal length of the receiving lens group in the meridional and sagittal directions different. Therefore, the light spot on the detection surface is in the meridional direction. The size in the direction is different from the size in the sagittal direction. The focal length ratio of the receiving lens group is greater than or equal to 1.2. The angular magnification of the non-rotationally symmetric lens group in the sagittal direction is greater than 1, which can expand the size of the light spot in the sagittal direction. Such an arrangement can, on the one hand, disperse the light spot and avoid Energy concentration damages the detector. On the other hand, when the spot in the sagittal direction is small, the deviation caused by the assembly of the laser receiving system has a greater impact on the spot. For example, if the spot diameter is 1mm, if the laser receiving system is assembled The deviation caused is 0.5mm, so the impact of the deviation on the light spot is 50%, which cannot meet the tolerance requirements of the laser receiving system. In order to meet the requirements, the precision requirements for the assembly of the laser receiving system are often high, and the assembly belt is reduced as much as possible. However, this makes the assembly of the laser receiving system more difficult. In the embodiment of the present application, by expanding the spot size in the sagittal direction, for example, the spot diameter can be 5 mm. At this time, if the laser receiving system is assembled with The original deviation is 0.5mm, but the impact of this deviation on the light spot is 10%, which reduces the impact of the deviation caused by the assembly of the laser receiving system on the light spot, increasing the allowable deviation range when assembling the laser receiving system, so that the laser The receiving system is less difficult to assemble. In addition, due to the large size of the light spot in the sagittal direction, the detector can detect more energy, which helps to increase the detection distance of the lidar. In addition, the light spot on the detection surface is not easily lost.

In a possible implementation, the lens closest to the object side in the receiving lens group has positive optical focus in the sagittal direction. Spend. With this arrangement, the lens closest to the object side has the effect of condensing light, so that the size of the lens located behind the lens closest to the object side can be reduced along the optical axis direction.

In a possible implementation, the receiving lens group satisfies the conditional expression: IHy/EFLy≥0.1, where IHy is the image height of the receiving lens group in the meridian direction, and EFLy is the image height of the receiving lens group in the meridian direction. focal length in direction. Such an arrangement can improve the receiving field of view angle of the laser receiving system in the meridional direction, so that the laser receiving system can receive laser light within a larger field of view.

In a possible implementation, the receiving lens group satisfies the conditional expression: D/IH≥1, where D is the lens diameter of the lens closest to the image side in the receiving lens group, and IH is the The image height of the receiving lens group. Such an arrangement allows the receiving lens group to form an image telecentric optical path, which helps to increase the energy detected by the detector.

In a possible implementation, the receiving lens group satisfies the conditional expression: EFL1/EFL2≥1.5, where EFL1 is the focal length of the non-rotationally symmetric lens group, and EFL2 is the focal length of the rotationally symmetrical lens group. Such an arrangement, on the one hand, makes the focal length of the non-rotationally symmetric lens group finite, which helps to expand the size of the light spot in the sagittal direction; on the other hand, it makes the image spot larger in the meridional direction than the size in the sagittal direction.

In a possible implementation, the laser receiving system satisfies the conditional expression: 0.2≤EPDx/EPDy≤5, where EPDx is the entrance pupil diameter of the laser receiving system in the sagittal direction, and EPDy is the laser The entrance pupil diameter of the receiving system in the meridional direction. Such an arrangement helps to increase the application range of the laser receiving system. The laser receiving system can be matched with laser transmitting systems of various specifications, thereby increasing the energy received by the laser receiving system.

In a possible implementation, the at least one non-rotationally symmetric lens is a cylindrical mirror or a free-form mirror.

In a possible implementation, the object side of the lens closest to the object side in the non-rotationally symmetric lens group is a convex surface. This setting can prevent the lens from accumulating dust and affecting the imaging effect.

In a possible implementation, the non-rotationally symmetrical lens group includes at least two non-rotationally symmetrical lenses. Such an arrangement helps to further expand the size of the light spot in the sagittal direction.

In a possible implementation, the number of the at least two non-rotationally symmetrical lenses is 2 to 4; the material of the at least one non-rotationally symmetrical lens is plastic or glass. Such an arrangement helps to reduce the cost of the non-rotationally symmetrical lens group and at the same time makes the assembly of the non-rotationally symmetrical lens group less difficult.

In a possible implementation, the number of the at least three rotationally symmetrical lenses is 3 to 7; the rotationally symmetrical lens group includes any one or two of the following lenses: aspherical lenses or spherical lenses; At least three rotationally symmetric lenses are made of plastic or glass. Such an arrangement helps to reduce the cost of the rotationally symmetrical lens group and at the same time makes it easier to assemble the rotationally symmetrical lens group.

In a possible implementation, the rotationally symmetric mirror group is located between the non-rotationally symmetric mirror group and the detector. With this arrangement, on the one hand, the non-rotationally symmetric mirror group and the rotationally symmetrical mirror group can be separately inspected. On the other hand, the non-rotationally symmetrical mirror group and the rotationally symmetrical mirror group can be composed separately, which reduces the difficulty of assembling the receiving mirror group.

In a possible implementation, the lens closest to the object side in the rotationally symmetric lens group has positive refractive power. With this arrangement, the rotationally symmetrical lens has the function of condensing light, which helps to reduce the size of the rotationally symmetrical lens located behind the rotationally symmetrical lens.

In a possible implementation, the object side of the lens closest to the object side in the rotationally symmetric lens group is a convex surface. Helps prevent the lens from accumulating dust and affecting the imaging effect.

In a possible implementation, the receiving lens group further includes: at least one optical filter, and the at least one optical filter is located in the non-rotationally symmetric lens group. Filters can filter stray light that is not conducive to imaging and help improve imaging quality.

In a possible implementation, it also includes: at least one reflecting mirror, the at least one reflecting mirror is located in the receiving lens group and used to refract the light path from the object side to the image side. Reflectors can refract the optical path, reduce the size of the receiving lens group in a certain direction, and help improve the compactness of the laser receiving system.

In a possible implementation, at least one lens in the receiving lens group is provided with a diffractive optical element. Helps reduce the total optical length (Total Track Length, TTL) of the receiving lens group.

In a possible implementation, the receiving lens group further includes: a square aperture, the square aperture is located on a side of the receiving lens group facing the object side. The square diaphragm can increase the light incident area of the receiving lens group and help improve the detection capability of the laser receiving system.

A second aspect of the present application provides a laser radar, which at least includes a laser emission system and any of the above laser interfaces. Collection system.

A third aspect of the present application provides an electronic device, which at least includes a body and the above-mentioned lidar, and the lidar is installed on the body.

A fourth aspect of the present application provides a vehicle, which at least includes a vehicle body and the lidar as described above, and the lidar is installed on the vehicle body.

A fifth aspect of the present application provides a lens assembly, which is a receiving lens group in any laser receiving system as described in the first aspect.

Description of drawings

Figure 1 is a schematic diagram of a scene of a lidar application vehicle provided by an embodiment of the present application;

Figure 2 is a schematic structural diagram of the laser radar provided by the embodiment of the present application;

Figure 3 is a schematic structural diagram of a laser receiving system provided by an embodiment of the present application;

Figure 4 is a schematic structural diagram of the first receiving lens group in the sagittal direction provided by the embodiment of the present application;

Figure 5 is a schematic structural diagram of the second receiving lens group in the sagittal direction provided by the embodiment of the present application;

Figure 6 is a schematic structural diagram of the third receiving lens group in the sagittal direction provided by the embodiment of the present application;

Figure 7 is a schematic structural diagram of the fourth receiving lens group in the sagittal direction provided by the embodiment of the present application;

Figure 8 is a schematic structural diagram of the fifth receiving lens group in the sagittal direction provided by the embodiment of the present application;

Figure 9 is a schematic structural diagram of the sixth receiving lens group in the sagittal direction provided by the embodiment of the present application;

Figure 10 is a schematic structural diagram of the seventh receiving lens group in the sagittal direction provided by the embodiment of the present application;

Figure 11 is a schematic structural diagram of the eighth receiving lens group in the sagittal direction provided by the embodiment of the present application;

Figure 12 is a schematic structural diagram of the receiving lens group in the meridian direction according to Embodiment 1 of the present application;

Figure 13 is a schematic structural diagram of the receiving lens group provided in Embodiment 1 of the present application in the sagittal direction;

Figure 14 is a defocus curve of the receiving lens group of a laser receiving system provided in Embodiment 1 of the present application;

Figure 15 is a distortion curve diagram of the receiving lens group of a laser receiving system provided in Embodiment 1 of the present application;

Figure 16 is a point diagram of the receiving lens group in the full field of view of a laser receiving system provided in Embodiment 1 of the present application;

Figure 17 is a schematic structural diagram of the receiving lens group provided in Embodiment 2 of the present application in the sagittal direction;

Figure 18 is a defocus curve diagram of a receiving lens group of a laser receiving system provided in Embodiment 2 of the present application;

Figure 19 is a distortion curve diagram of the receiving lens group of a laser receiving system provided in Embodiment 2 of the present application;

Figure 20 is a point diagram of the receiving lens group in the full field of view of a laser receiving system provided in Embodiment 2 of the present application;

Figure 21 is a schematic structural diagram of the receiving lens group provided in the third embodiment of the present application in the sagittal direction;

Figure 22 is a defocus curve diagram of a receiving lens group of a laser receiving system provided in Embodiment 3 of the present application;

Figure 23 is a distortion curve diagram of the receiving lens group of a laser receiving system provided in Embodiment 3 of the present application;

Figure 24 is a point diagram of the receiving lens group in the full field of view of a laser receiving system provided in Embodiment 3 of the present application.

Explanation of reference symbols:
100. Laser receiving system;
110. Receiving lens group;
111. Non-rotationally symmetrical lens group; 1111. Non-rotationally symmetrical lens;
112. Rotationally symmetrical lens group; 1121. Rotationally symmetrical lens; 1122. Plane mirror;
113. Optical filter;
114. Reflector;
115. Diffractive optical elements;
116. Square diaphragm;
120. Detector;
200. Laser emission system;
1000. LiDAR;
2000, vehicles;
210. Vehicle body.

Detailed ways

The terms used in the embodiments of the present application are only used to explain specific embodiments of the present application and are not intended to limit the present application.

To facilitate understanding, the relevant technical terms involved in the embodiments of this application are first explained and described.

The meridian plane refers to the plane formed by the chief ray of the off-axis object point and the main axis of the optical system.

The meridional direction refers to the direction perpendicular to the optical axis and parallel to the meridian plane (for example, refer to the Y direction in Figure 4).

The sagittal direction refers to the direction perpendicular to the meridional direction (for example, refer to the X direction in Figure 4).

The object side is bounded by the receiving lens group, the side where the detected object is located is the object side, and the side of the lens facing the object side is the object side of the lens.

The image side is bounded by the receiving lens group, the side where the detector is located is the image side, and the side of the lens facing the image side is the image side of the lens.

Positive power means that the lens has a positive focal length and has the effect of condensing light.

Field of View (FOV), with the receiving lens group as the vertex, and the angle formed by the two edges of the maximum range through which the image of the object to be detected can pass through the receiving lens group is called the field of view angle.

Diaphragm: An entity in an optical system that limits a light beam, such as a fixed or variable apertured barrier, lens, etc.

Entrance pupil: The effective aperture that limits the incident light beam. It is the image formed by the aperture diaphragm on the front optical system. The aperture diaphragm is the optical hole that limits the aperture angle of the on-axis point imaging beam.

The entrance pupil diameter refers to the aperture size that limits the incident light beam.

Optical power represents the ability of a lens to refract incident parallel light beams.

The optical axis refers to the straight line passing through the center of each lens in the receiving lens group (for example, refer to the Z direction in Figure 3).

Focal length, also known as focal length, is a measure of the concentration or emission of light in an optical system. It means that when an infinite scene passes through a lens or lens group to form a clear image on the focal plane, the optical center of the lens or lens group reaches The vertical distance of the focus. From a practical perspective, it can be understood as the distance from the center of the lens (receiving lens group) to the image plane.

Effective focal length (EFL) refers to an optical system with several lenses or mirrors. The focal length of the optical system is represented by the effective focal length.

The total optical length (Total Track Length, referred to as TTL) refers to the total length from the vertex of the first lens set adjacent to the object side in the receiving lens group to the imaging surface of the receiving lens group, that is, from the first lens to the detection surface of the detector. distance.

Image Heigth (IH for short), also known as image height, refers to the total image height of the image formed by the receiving lens group.

Distortion, also known as distortion, usually refers to the degree of distortion of the image formed by the receiving lens group relative to the object itself. The height of the intersection between the chief rays of different fields of view and the Gaussian image plane after passing through the receiving lens group is not equal to the ideal image height, and the difference between the two is distortion.

A rotationally symmetrical lens group means that the lenses that constitute a rotationally symmetrical lens group are all rotationally symmetrical lenses. Among them, rotationally symmetrical lenses refer to lenses that are symmetrical after rotating around their own center.

Non-rotationally symmetric lens group means that the lenses that make up the non-rotationally symmetrical lens group are all non-rotationally symmetrical lenses. Among them, non-rotationally symmetric lenses refer to lenses that are asymmetric after rotating around their own center.

Micro-Electro-Mechanical System (MEMS), also known as microelectromechanical system, microsystem, micromachinery, etc., refers to high-tech devices with dimensions of several millimeters or even smaller.

Focal length ratio refers to the ratio of the focal length of the lens or lens group in the sagittal direction to the focal length of the lens or lens group in the meridional direction.

The lidar 1000 provided in the embodiment of the present application can be applied to the vehicle 2000. The lidar is used as an auxiliary component of the intelligent driving system to detect surrounding vehicles 2000, pedestrians, obstacles, etc. The lidar 1000 in the embodiment of the present application can also be applied to electronic equipment such as drones, smart furniture equipment, or manufacturing equipment. For example, the electronic equipment includes a body, and the lidar 1000 can be installed on the body. Of course, the lidar 1000 in the embodiment of the present application can also be applied to military, environmental science, biological science and other fields.

In the embodiment of the present application, the application of lidar 1000 to vehicle 2000 is used as an example for explanation. The vehicle 2000 can be an electric vehicle/electric vehicle (EV for short) or an electric food delivery vehicle, or it can also be an electric express delivery vehicle. , or the vehicle 2000 can be a pure electric vehicle (Pure Electric Vehicle/Battery Electric Vehicle, referred to as: PEV/BEV), a hybrid electric vehicle (Hybrid Electric Vehicle, referred to as: HEV), or an extended-range electric vehicle (Range Extended Electric Vehicle (REEV for short), plug-in hybrid electric vehicle (PHEV for short), and new energy vehicle (New Energy Vehicle).

Figure 1 is a schematic diagram of a scene of a vehicle for lidar application provided by an embodiment of the present application. Referring to FIG. 1 , a vehicle 2000 includes a vehicle body 210 and at least one lidar 1000 . For example, in FIG. 1 , three laser radars 1000 are provided on the vehicle body 210 . The lidar 1000 can be installed on the roof, lights, front windshield, bumper and other parts of the vehicle body 210, and is not specifically limited in the embodiment of this application. For example, in FIG. 1 , two lidars 1000 are provided on the front bumper of the vehicle body 210 , and one lidar 1000 is provided on the rear bumper of the vehicle body 210 . It should be noted that the number of lidar 1000 includes but is not limited to 3.

Figure 2 is a schematic structural diagram of a lidar provided by an embodiment of the present application.

Referring to FIG. 2 , an embodiment of the present application provides a lidar 1000 , which includes at least a laser transmitting system 200 , a laser receiving system 100 and a scanner. During the working process of the lidar 1000, the laser transmitting system 200 is used to emit a laser beam toward the target to be detected. After the laser beam encounters the target and is diffusely reflected, part of the laser beam will be reflected back to the lidar 1000 and be received by the laser receiving system 100. take over.

The scanner is used to direct the laser beams emitted by the laser emitting system 200 to different field of view areas, and to reflect the laser beam reflected by the target object to the laser receiving system 100 for reception, so as to detect the different field of view areas. For example, in some examples, the scanner can rotate both the laser emitting system 200 and the laser receiving system 100 to achieve detection of different field of view areas. Or, in other examples, during the scanning process, the scanner is a movable scanning mirror, and the laser emitting system 200 and the laser receiving system 100 are fixed. The scanning mirror reflects the laser beam emitted by the laser emitting system 200 and passes through the target. The laser beam reflected back from the object can also detect different fields of view. Among them, the scanning mirror can be a MEMS or 2D galvanometer.

In the embodiment of the present application, the laser emission system 200 may include a laser and a emission lens group (not shown in the figure). The emission lens group is used to move the laser beam emitted by the laser in a direction toward the target object, so that the laser beam comes into contact with the target object so that the lidar 1000 can detect the target object. Wherein, when the scanner is a movable scanning mirror, the emission lens group reflects the laser beam emitted by the laser to the scanning mirror and reflects with the scanning mirror, and then the laser beam contacts the target object. In addition, the laser may be a 905nm semiconductor laser, a 1550nm fiber laser or a laser with other wavelengths. At the same time, the emitting lens group may include one or more of the following lenses: spherical lens, aspheric lens or cylindrical lens, which are not specifically limited in the embodiments of this application. In addition, the number of lenses in the emitting lens group is at least one, which is not specifically limited in the embodiments of the present application. For example, the emitting lens group includes a spherical mirror, or the emitting lens group includes a cylindrical mirror and an aspherical mirror.

Figure 3 is a schematic structural diagram of a laser receiving system provided by an embodiment of the present application.

In the embodiment of the present application, referring to FIG. 3 , the excitation receiving system may include a detector 120 and a receiving lens group 110 . Among them, the detector 120 is used to receive the laser beam that passes through the receiving lens group 110, so as to form an image on the detection surface of the detector 120. Specifically, a light spot is formed on the detection surface of the detector 120. Among them, the size of the light spot formed on the detection surface will affect the service life of the detector 120, the difficulty of mass production coupling between the receiving lens group 110 and the detector 120, or the detection distance of the lidar 1000.

Among them, the detector 120 can be an avalanche photodiode (Avalanche Photodiode, APD), a PIN photodiode (PIN Photodiode, PIN PD), a single photon avalanche diode (Single Photo Avalanche photodiode, SPAD) or a multi-pixel photon counter (Multi-pixel photo counter, MPPC), etc. In addition, the specific type of the detector 120 may be determined according to detection requirements, which are not specifically limited here. The detection requirements include at least one or more of the following indicators: detection sensitivity, detection distance, or response speed.

The size of the light spot indicates the concentration of energy detected by the detector 120. The smaller the light spot, the more concentrated the energy, and the more concentrated the energy, the easier it is to cause damage to the detector 120. The size of the light spot in the sagittal direction (for example, refer to the X direction in FIG. 4 ) reflects the difficulty of mass-production coupling between the receiving lens group 110 and the detector 120 and the amount of energy that the detector 120 can detect. The difficulty of mass production coupling between the receiving lens group 110 and the detector 120 is inversely proportional to the size of the light spot in the sagittal direction. The larger the size of the light spot in the sagittal direction, the greater the difficulty in mass production coupling between the receiving lens group 110 and the detector 120 The smaller. The larger the size of the light spot in the sagittal direction, the greater the energy that the detector 120 can detect, and the amount of energy is proportional to the detection distance of the lidar 1000 .

It should be noted that the difficulty of mass production coupling of the receiving lens group 110 and the detector 120 also indicates the difficulty of assembly of the laser receiving system 100. The greater the difficulty of mass production coupling of the detector 120 of the receiving lens group 110, Then, the installation deviation between the receiving lens group 110 and the detector 120 will be smaller, so as to reduce the energy loss and allow the detector 120 to detect more energy. Among them, partial The size of the difference also indicates the assembly difficulty of the laser receiving system 100. The smaller the deviation, the greater the assembly difficulty. In addition, the deviation refers to the difference between the actual alignment length of the detector 120 and the receiving lens group 110 and the preset symmetry length in the sagittal direction.

The receiving lens group 110 in the related art is a rotationally symmetrical lens group 112. The rotationally symmetrical lens group 112 includes a plurality of rotationally symmetrical lenses 1121, and each rotationally symmetrical lens is any one of the following lenses: a spherical lens or an aspherical lens. Since the rotationally symmetrical lens 1121 is a centrally rotationally symmetrical lens, the focal length of the receiving lens group 110 in the meridional direction is the same as the focal length of the receiving lens group 110 in the sagittal direction, and the size of the light spot on the detection surface in the meridional direction is equal to The dimensions in the sagittal direction are essentially the same, which results in the image plane height in the horizontal field of view being the same as the image plane height in the vertical field of view.

However, since the size of the light spot in the sagittal direction is basically the same as the size of the light spot in the meridional direction, the size of the light spot in the sagittal direction is limited by the size of the light spot in the meridional direction. In other words, the size of the light spot in the meridional direction What is the size, then the size of the light spot in the sagittal direction is also large. However, for the rotationally symmetric lens group 112, the size of the light spot in the meridional direction is very small, so the overall light spot is very small. When the entire light spot is small, the energy gathered in the area opposite to the light spot on the detection surface is very concentrated. In other words, the energy value contained in the light spot is very high, which makes the detector 120 easily damaged. Since the size of the light spot in the sagittal direction is small, this results in a small deviation between the receiving lens group 110 and the detector 120 when installed to increase the energy received by the detector 120. However, a small deviation will cause the receiving lens group 110 to be in contact with the detector. The mass production coupling of 120 is difficult and affects the detection range of the lidar 1000. In addition, the small deviation increases the difficulty of assembling the laser receiving system 100.

Based on this, embodiments of the present application provide a laser receiving system 100. The focal length of the laser receiving system 100 in the sagittal direction is greater than its focal length in the meridional direction, and can expand the size of the light spot in the sagittal direction. Set like this, On the one hand, the overall size of the light spot can be enlarged to avoid excessive concentration of energy and damage to the detector 120. On the other hand, the alignment length of the detector 120 and the receiving lens group 110 in the sagittal direction can be increased, thereby reducing the length of the detector 120 and the receiving lens group 110. The mass production coupling of the receiving lens group 110 is difficult, and the deviation during installation of the detector 120 and the receiving lens group 110 is increased, thereby reducing the assembly difficulty of the laser receiving system 100. In addition, due to the enlarged size of the light spot in the sagittal direction, the light spot is not easily lost from the detection surface, which can reduce energy loss and enable the detector 120 to detect more, which helps ensure the detection range of the lidar 1000.

Figure 4 is a schematic structural diagram of the first receiving lens group in the sagittal direction provided by the embodiment of the present application. Figure 5 is a schematic structural diagram of the second receiving lens group provided by the embodiment of the present application in the sagittal direction. Figure 6 Figure 7 is a schematic structural diagram of the fourth receiving lens group in the sagittal direction provided by the embodiment of the present application.

Referring to FIG. 4 , along the optical axis direction from the object side to the image side (Z direction in FIG. 4 ), the laser receiving system 100 of the embodiment of the present application includes a receiving lens group 110 and a detector 120 . The receiving lens group 110 is used to make the laser beam reflected by the target object contact the detector 120 to form a light spot on the detection surface of the detector 120 . Along the optical axis direction from the object side to the image side, the receiving lens group 110 at least includes a non-rotationally symmetric lens group 111 and a rotationally symmetric lens group 112 . Referring to FIG. 4 , the non-rotationally symmetric lens group 111 includes at least one non-rotationally symmetrical lens 1111 . It can be understood that the number of the non-rotationally symmetrical lens 1111 is more than one. For example, with reference to FIGS. 4 to 6 , the non-rotationally symmetrical lens 1111 The quantity is 1, 2, 3, 4 and so on. Referring to FIG. 4 , the role of the rotationally symmetric mirror group 112 is to adjust the direction of the laser beam passing through the non-rotationally symmetric mirror group 111 to ensure that the laser beam reflected by the target object can contact the detection surface of the detector 120 . The rotationally symmetric lens group 112 includes at least three rotationally symmetric lenses 1121. This arrangement can ensure that the quality of the light spot formed on the detection surface meets the detection requirements. It can be understood that the number of rotationally symmetrical lenses 1121 is more than three. For example, the number of rotationally symmetrical lenses 1121 is 3, 4, 5, 6, etc.

Among them, the non-rotationally symmetric lens 1111 has the following characteristics: the optical power of the non-rotationally symmetrical lens 1111 in the meridional direction (Y direction in Figure 4) and its optical power in the sagittal direction (X direction in Figure 4) are different, so that the focal length ratio of the non-rotationally symmetric lens group 111 is greater than 1 or less than 1. In other words, the focal length of the non-rotationally symmetric lens group 111 in the sagittal direction is not equal to the focal length of the non-rotationally symmetric lens group 111 in the meridional direction. Among them, the focal length ratio is equal to the focal length in the sagittal direction/the focal length in the meridional direction.

Since the focal lengths of the non-rotationally symmetric lens group 111 in the sagittal direction and the meridional direction are different, the focal lengths of the receiving lens group 110 in the sagittal direction and the meridional direction are also different, which causes the light spot to be in the meridional and sagittal directions. The sizes are also different. Therefore, the size of the light spot in the sagittal direction can be enlarged by using the non-rotationally symmetric lens group 111 . It can be understood that when the size of the light spot in the sagittal direction is enlarged, the alignment length of the receiving lens group 110 and the detector 120 is increased, and the detector 120 can detect more energy. In addition, the receiving lens group 110 can be improved and the deviation when the detector 120 is installed to reduce the assembly difficulty of the laser receiving system 100, and while increasing the deviation, the detector 120 can still receive more energy to ensure that the laser radar Detection distance up to 1000. In addition, since the size of the light spot in the sagittal direction is enlarged, the overall size of the light spot also becomes larger. In other words, the light spot is dispersed, so that the energy concentrated on the detection surface is dispersed to avoid damaging the detector 120 .

Specifically, the receiving lens group 110 in the embodiment of the present application satisfies the conditional expression EFLx/EFLy≥1.2, where EFLx is the focal length of the receiving lens group 110 in the sagittal direction, EFLy is the focal length of the receiving lens group 110 in the meridional direction, In addition, the angular magnification of the non-rotationally symmetric lens group 111 in the sagittal direction is greater than 1.

The angular magnification of the non-rotationally symmetrical lens group 111 is greater than 1, so that the non-rotationally symmetrical lens group 111 can expand the light spot. In addition, the non-rotationally symmetrical lens group 111 makes the focal length ratio of the receiving lens group 110 greater than or equal to 1.2 (receiving The lens group 110 satisfies the above conditional expression). Such arrangement can expand the focal length of the receiving lens group 110 in the sagittal direction, thereby expanding the size of the light spot in the sagittal direction, which can reduce the difficulty of mass production coupling, assembly, and avoidance of Detector 120 is damaged.

It can be understood that the angular magnification of the non-rotationally symmetric lens group 111 can be 1.1, 1.2, 1.21, 1.315, 1.5, 2 and other values, which can be determined according to the detection requirements, and are not specifically limited here. In addition, the angular magnification of the non-rotationally symmetric lens group 111 can be adjusted through parameters such as the lens arrangement, lens material, and thickness in the non-rotationally symmetric lens group 111 .

It should be noted that the larger the focal length ratio of the receiving lens group 110, the larger the size of the light spot in the sagittal direction. Therefore, the focal length ratio of the receiving lens group 110 can be determined according to the detection requirements of the lidar 1000, which will not be discussed here. Specific limitations include, for example, the focal length ratio of the receiving lens group 110 being 1.2, 1.25.1.258, 1.5, 1.59, 1.6, 1.7, 1.8, 1.87, 1.9, 1.9421, 2.0 and other values.

The focal length ratio of the receiving lens group 110 can be adjusted in any one or more of the following ways: 1. The number, thickness, and material of the non-rotationally symmetrical lens group 111 can be adjusted, and the non-rotationally symmetrical lens group 111 has multiple lenses. 2. The number, thickness, and material of the lenses of the rotationally symmetric lens group 112 can be adjusted. When the rotationally symmetric lens group 112 has multiple lenses, the distance between two adjacent lenses can be adjusted. 3. Rotation symmetry The arrangement of the lenses of the lens group 112 and the lenses of the non-rotationally symmetric lens group 111 . It should be noted that the method of adjusting the focal length ratio of the receiving lens group 110 is not limited to the methods listed in the embodiments of this application.

The lenses of the rotationally symmetrical lens group 112 and the lenses of the non-rotationally symmetrical lens group 111 are arranged in the following ways: first, all the lenses of the non-rotationally symmetrical lens group 111 are not mixed with all the lenses of the rotationally symmetrical lens group 112; And all the lenses of the non-rotationally symmetric lens group 111 are individually arranged in sequence along the optical axis direction, and all the lenses of the rotationally symmetric lens group 112 are individually arranged in sequence along the optical axis direction. Second, all the lenses of the non-rotationally symmetric lens group 111 are mixed with all the lenses of the rotationally symmetric lens group 112 . In other words, at least one lens of the non-rotationally symmetric lens group 111 is located in the rotationally symmetric lens group 112 .

When the rotationally symmetrical lens group 112 and the non-rotationally symmetrical lens group 111 are arranged separately, the non-rotationally symmetrical lens group 111 can be close to the object side, and the rotationally symmetrical lens group 112 can be close to the image side (refer to Figure 4), or the non-rotationally symmetrical lens group 112 can be close to the image side (refer to Figure 4). The lens group 111 may be close to the image side, and the rotationally symmetric lens group 112 may be close to the object side (not shown in the figure).

Among them, the non-rotationally symmetric lens group 111 is close to the object side, and the rotationally symmetrical lens group 112 is close to the image side. In other words, the rotationally symmetrical lens group 112 is located between the non-rotationally symmetrical lens group 111 and the detector 120. Such an arrangement can, on the one hand, make The non-rotationally symmetric lens group 111 and the rotationally symmetrical lens group 112 are assembled separately, which can reduce the assembly difficulty of the receiving lens group 110. On the other hand, the non-rotationally symmetrical lens group 111 and the rotationally symmetrical lens group 112 can be separately inspected.

Separate detection refers to separately detecting the non-rotationally symmetric lens group 111 and the rotationally symmetrical lens group 112. The non-rotationally symmetrical lens group 111 and the rotationally symmetrical lens group 112 will not interfere with each other. For example, when detecting the non-rotationally symmetrical lens group 111, The rotationally symmetric lens group 112 is removed, leaving only the non-rotationally symmetric lens group 111 to determine whether the non-rotationally symmetric lens group 111 is assembled. In the same way, when detecting the rotationally symmetrical lens group 112, the non-rotationally symmetrical lens group 111 can be disassembled.

In the embodiment of the present application, the optical power in the sagittal direction of the lens closest to the object side in the receiving lens group 110 may be negative optical power or positive optical power. In some examples, the lens closest to the object side in the receiving lens group 110 has positive refractive power in the sagittal direction, so that the lens closest to the object side has the effect of condensing light. Such an arrangement can reduce the light intensity along the optical axis. Small size of all lenses behind the lens closest to the object side. Among them, the lens closest to the object side may be a lens of the non-rotationally symmetric lens group 111 , or the lens closest to the object side may be a lens of the rotationally symmetric lens group 112 .

When the non-rotationally symmetric mirror group 112 and the rotationally symmetric mirror group 112 are arranged separately, and the rotationally symmetric mirror group 112 is located between the non-rotationally symmetric mirror group 111 and the detector 120, the rotationally symmetric mirror group 112 is closest to the object side. The lens has positive power, so that the size of the lens behind the lens closest to the object side in the rotationally symmetric lens group 112 can be reduced. Therefore, the lens closest to the object side in the non-rotationally symmetric lens group 111 is in the sagittal direction. While having positive refractive power, the lens closest to the object side in the rotationally symmetric lens group 112 also has positive refractive power. Such an arrangement can make the size of some lenses in the receiving lens group 110 smaller.

In the embodiment of the present application, the receiving lens group 110 satisfies the conditional expression: IHy/EFLy ≥ 0.1, where IHy is the image height of the receiving lens group 110 in the meridional direction, and EFLy is the focal length of the receiving lens group 110 in the meridional direction. With such an arrangement, the receiving field of view angle of the laser receiving system 100 in the meridional direction can be increased, so that the laser receiving system 100 can receive laser light within a larger field of view.

In the embodiment of the present application, the receiving lens group 110 satisfies the conditional expression: D/IH≥1, where D is the lens diameter of the lens closest to the image side in the receiving lens group 110, and IH is the image height of the receiving lens group 110. Such an arrangement allows the receiving lens group 110 to form an image telecentric optical path, which helps to increase the energy detected by the detector 120 .

In the embodiment of the present application, the receiving lens group 110 can also satisfy the conditional expression: EFL1/EFL2≥1.5, where EFL1 is the focal length of the non-rotationally symmetrical lens group 111, and EFL2 is the focal length of the rotationally symmetrical lens group 112. With this setting, on the one hand The focal length of the non-rotationally symmetric lens group 111 is finite, which helps to expand the size of the light spot in the sagittal direction. On the other hand, the size of the image spot in the meridional direction is larger than the size in the sagittal direction.

In the embodiment of this application, the laser receiving system 100 satisfies the conditional expression: 0.2≤EPDx/EPDy≤5, where EPDx is the entrance pupil diameter of the laser receiving system 100 in the sagittal direction, and EPDy is the entrance pupil diameter of the laser receiving system 100 in the meridional direction. entrance pupil diameter. Such an arrangement helps to increase the application range of the laser receiving system 100. The laser receiving system 100 can be matched with laser emitting systems 200 of various specifications, thereby increasing the energy received by the laser receiving system 100.

Among them, when the laser is emitted to the system and the energy emitted in the sagittal direction is large, then the entrance pupil diameter of the laser receiving system 100 in the sagittal direction is increased, or when the laser is emitted to the system and the energy emitted in the meridional direction is large, then the entrance pupil diameter of the laser receiving system 100 is increased. The entrance pupil diameter of the laser receiving system 100 in the meridional direction is increased.

In a possible implementation, the non-rotationally symmetrical lens group 111 includes at least two non-rotationally symmetrical lenses 1111 . The number of non-rotationally symmetrical lenses 1111 can be determined according to the focal length ratio of the receiving lens group 110 and the material of the non-rotationally symmetrical lens 1111 , thickness and other parameters, which are not specifically limited in the embodiment of the present application. For example, the number of non-rotationally symmetric lenses 1111 is 2, 3, 4, 5, 6, 7 and other values.

It can be understood that, compared with the non-rotationally symmetrical lens group 111 using one non-rotationally symmetrical lens 1111, the non-rotationally symmetrical lens group 111 including at least two non-rotationally symmetrical lenses 1111 uses an imaging concept to expand the light spot and does not introduce new For example, it does not cause a lot of noise, so there is no need to install additional noise removal or noise reduction devices, and the cost of the laser receiving system 100 can be reduced.

In one possible implementation, the number of non-rotationally symmetrical lenses 1111 constituting the non-rotationally symmetrical lens group 111 is 2 to 4 pieces. Such an arrangement can take into account both the difficulty and cost of assembling the non-rotationally symmetrical lens group 111, making the non-rotationally symmetrical lens group 111 non-rotationally symmetrical. The rotationally symmetric lens group 111 has low cost and low assembly difficulty.

In the embodiment of the present application, the non-rotationally symmetric lens 1111 is a lens that is no longer symmetrical after rotating around the center. For example, the non-rotationally symmetric lens 1111 is a cylindrical mirror or a free-form mirror. Of course, the non-rotationally symmetric lens group 111 may include two types of non-rotationally symmetric lenses 1111 , or the non-rotationally symmetric lens group 111 may include one type of non-rotationally symmetric lens 1111 , for example, the non-rotationally symmetric lens group 111 Includes cylindrical mirrors and free-form mirrors.

In the embodiment of the present application, the material of the non-rotationally symmetric lens 1111 may be plastic, or the material of the non-rotationally symmetric lens 1111 may be glass, or the material of part of the non-rotationally symmetric lens 1111 may be plastic, and part of the non-rotationally symmetric lens 1111 may be made of plastic. The material of 1111 can be glass.

In the embodiment of the present application, the object side of the lens closest to the object side in the non-rotationally symmetric lens group 111 is convex or concave. When the object side of the lens closest to the object side in the non-rotationally symmetric lens group 111 is convex, it can be This prevents dust from accumulating on the non-rotationally symmetric lens 1111 and affecting the imaging effect.

In one possible implementation, the total number of rotationally symmetrical lenses 1121 is 3 to 7 pieces. Such an arrangement helps to balance the cost and assembly difficulty of the rotationally symmetrical lens group 112, making the cost of the rotationally symmetrical lens group 112 small. , Easy to assemble.

In the embodiment of the present application, the rotationally symmetrical lens 1121 group includes any one or two of the following lenses: aspherical lenses or spherical lenses. In other words, there is at least one type of rotationally symmetrical lens 1121 that constitutes the rotationally symmetrical lens 1121 group, for example, The rotationally symmetric lenses 1121 that make up the rotationally symmetric lens group 1121 are all aspheric mirrors, or the rotationally symmetric lenses 1121 that make up the rotationally symmetric lens group 1121 are all spherical mirrors, or some of the rotationally symmetric lenses 1121 that make up the rotationally symmetric lens group 1121 are all aspherical lenses. Spherical mirrors, some of the rotationally symmetrical lenses 1121 constituting the rotationally symmetrical lens group 1121 are all spherical mirrors.

In the embodiment of the present application, all rotationally symmetrical lenses 1121 are made of plastic, or all rotationally symmetrical lenses 1121 are made of glass, or some of the rotationally symmetrical lenses 1121 are made of plastic, and some of the rotationally symmetrical lenses are made of plastic. The material of 1121 is glass.

In the embodiment of the present application, the object side of the lens closest to the object side in the rotationally symmetric lens group 112 is convex or concave. When the object side of the lens closest to the object side in the rotationally symmetric lens group 112 is convex, this can be avoided. Dust accumulates on the rotationally symmetrical lens 1121 and affects the imaging effect.

In some examples, the rotationally symmetric lens group 112 can also include at least one plane mirror 1122. The plane mirror 1122 is used as a filter 113, which can filter stray light that is not conducive to imaging and improve imaging quality. At least one plane mirror 1122 may be disposed close to the image side. In other words, the filter 113 of the rotationally symmetrical lens group 112 is located between the rotationally symmetrical lens 1121 and the detector 120 .

FIG. 8 is a schematic structural diagram in the sagittal direction of the fifth receiving lens group provided by the embodiment of the present application.

In the embodiment of the present application, referring to FIG. 8 , the receiving lens group 110 may also include at least one optical filter 113 . The optical filter 113 is disposed in the optical path of the receiving lens group 110 . The optical filter 113 can make the light in a specific wavelength range Light passes through, thereby acting as a filter.

For example, when the non-rotationally symmetric lens group 111 and the rotationally symmetrical lens group 112 are provided separately, and the rotationally symmetrical lens group 112 is located between the non-rotationally symmetrical lens group 111, the filter 113 can be disposed in the non-rotationally symmetrical lens group 111 ( Referring to Figure 8), the light entering from the non-rotationally symmetric lens group 111 sequentially passes through the internal filter 113 and the rotationally symmetric lens group 112 before illuminating the detector 120. The filter 113 can filter out noise that is not conducive to imaging. light to improve image quality.

FIG. 9 is a schematic structural diagram in the sagittal direction of the sixth receiving lens group provided by the embodiment of the present application.

In the embodiment of the present application, referring to FIG. 9 , the receiving lens group 110 may also include at least one reflecting mirror 114 . The at least one reflecting mirror 114 is located in the receiving lens group 110 and is used to refract the optical path from the object side to the image side. This arrangement , can reduce the size of the receiving lens group 110 in a certain direction, help to improve the structural compactness of the receiving lens group 110, and reduce the space required for the installation of the receiving lens group 110. Among them, a certain direction may be the optical axis direction from the object side to the image side.

Wherein, all the reflecting mirrors 114 may be located in the non-rotationally symmetric mirror group 111 (as shown in FIG. 9 ), or all the reflecting mirrors 114 may be located in the rotationally symmetrical mirror group 112 , or the number of reflecting mirrors 114 is At least two pieces, the partial reflecting mirror 114 is located in the non-rotationally symmetric mirror group 111, and the partial reflecting mirror 114 is located in the rotationally symmetrical mirror group 112, or all the reflecting mirrors 114 are located in the non-rotationally symmetrical mirror group 111 and the rotationally symmetrical mirror group 112 or, the number of reflecting mirrors 114 is at least three, the partial reflecting mirror 114 is located in the non-rotationally symmetric mirror group 111 , the partial reflecting mirror 114 is located in the rotationally symmetrical mirror group 112 , and the partial reflecting mirror 114 is located in the non-rotationally symmetrical mirror group 112 111 and rotationally symmetrical lens group 112.

FIG. 10 is a schematic structural diagram in the sagittal direction of the seventh receiving lens group provided by the embodiment of the present application.

In the embodiment of the present application, referring to FIG. 10 , at least one lens in the receiving lens group 110 can be provided with a diffractive optical element 115 , and the diffractive optical element 115 can reduce the TTL length of the receiving lens group 110 . When the number of diffractive optical elements 115 is multiple, the lens with diffractive optical elements 115 may include at least one or two of the following lenses: non-rotationally symmetrical lens 1111 or rotationally symmetrical lens 1121 . For example, when the number of diffractive optical elements 115 is one, it can be disposed on the non-rotationally symmetric lens 1111 or the rotationally symmetrical lens 1121 , or when the number of diffractive optical elements 115 is two or more, some of the diffractive optical elements 115 can be disposed on the non-rotationally symmetric lens 1111 or the rotationally symmetric lens 1121 . On the symmetrical lens 1111, another part of the diffractive optical element 115 is provided on the rotationally symmetrical lens 1121.

FIG. 11 is a schematic structural diagram in the sagittal direction of the eighth receiving lens group provided by the embodiment of the present application.

In the embodiment of the present application, referring to Figure 11, the receiving lens group 110 may also include a square aperture 116. The square aperture 116 can increase the incident area, so that the receiving lens group 110 can receive the laser beam within a larger field of view. Therefore, the detector 120 can detect more energy, thereby improving the detection capability of the receiving lens group 110 . The square aperture 116 may be located on the side of the receiving lens group 110 facing the object side. In other words, the square aperture 116 may be located between the target object and the receiving lens group 110 , or the square aperture 116 may also be located adjacent to the receiving lens group 110 between the two lenses.

Wherein, square means that the shape of the through hole for the laser beam to pass through is rectangular. For example, the square aperture 116 is a square aperture 116 or a rectangular aperture 116.

The receiving lens group 110 and performance parameters of the laser receiving system 100 provided in this application will be described below with reference to specific embodiments.

Embodiment 1

Figure 12 is a schematic structural diagram of the receiving lens group in the meridian direction provided in the first embodiment of the present application. Figure 13 is a schematic diagram of the receiving lens group in the first embodiment of the present application. The provided structural diagram of the receiving lens group in the sagittal direction.

In this embodiment, referring to Figures 12 and 13, along the optical axis direction from the object side to the image side, the laser receiving system 100 includes a non-rotationally symmetric lens group 111, a rotationally symmetrical lens group 112 and a detector 120. In other words, the non-rotationally symmetrical lens group 112 and the detector 120. The rotationally symmetric lens group 111 and the rotationally symmetric lens group 112 are arranged separately. The non-rotationally symmetric lens group 111 is close to the object side, and the rotationally symmetric lens group 112 is close to the image side.

13, the non-rotationally symmetric lens group 111 includes two non-rotationally symmetrical lenses 1111, and the two non-rotationally symmetrical lenses 1111 are both cylindrical mirrors. In addition, the cylindrical surface closest to the object side of the two cylindrical mirrors is The object side of the mirror is convex, and the cylindrical mirror closest to the object side of the two cylindrical mirrors has positive power in the sagittal direction.

Referring to FIG. 13 , the rotationally symmetric lens group 112 includes three rotationally symmetric lenses 1121 and a plane mirror 1122 . The three rotationally symmetrical lenses 1121 are all aspherical lenses, which can balance the aberrations of the receiving lens group 110. In addition, the number of rotationally symmetrical lenses 1121 can be reduced, which is helpful for the optical assembly. The rotationally symmetrical lens 1121 closest to the object side among the three rotationally symmetrical lenses 1121 has positive optical power, and the object-side surface of the rotationally symmetrical lens 1121 closest to the object side among the three rotationally symmetrical lenses 1121 is convex. The plane mirror 1122 is located between the detector 120 and the three rotationally symmetric mirrors 1121.

The receiving lens group 110 also includes a filter 113 (refer to Figure 13), a diffractive optical element 115 (not shown in the figure) and a square aperture 116 (not shown in the figure). The filter 113 is located on two Between the cylindrical mirrors, they are used to filter stray light. The diffractive optical element 115 is disposed on a certain surface of any lens in the receiving lens group 110 .

The ratio of the focal length of the receiving lens group 110 in the sagittal direction to the focal length of the receiving lens group 110 in the meridional direction is:
EFLx/EFLy=25.18/12.913=1.95.

The angular magnification of the non-rotationally symmetric lens group 111 in the sagittal direction is 1.95.

The ratio of the image height of the receiving lens group 110 in the meridian direction to the focal length of the receiving lens group 110 in the meridian direction is: IHy/EFLy=6/12.913=0.4313.

The ratio of the entrance pupil diameter of the laser receiving system 100 in the sagittal direction to the entrance pupil diameter of the laser receiving system 100 in the meridional direction is: EPDx/EPDy=8/12.8=0.625. The ratio of the lens diameter of the lens closest to the image side in the receiving lens group 110 to the image height of the receiving lens group 110 is: D/IH=10.8/6=1.8.

The ratio of the focal length of the non-rotationally symmetric lens group 111 to the focal length of the rotationally symmetric lens group 112 is:
|EFL1/EFL2|＝＝10840/12.17＝840.

Table 1 below shows the optical parameters of each lens in the receiving lens group 110 of a laser receiving system 100 provided in Embodiment 1 of the present application.

Among them, L1 is the first cylindrical mirror closest to the object side, L2 is the filter 113, L3 is the second cylindrical mirror closest to the image side, and L4 is the first aspherical mirror closest to the object side. L5 is the second aspherical lens, L6 is the third aspherical lens closest to the image side, and L7 is the plane mirror 1122.

Among them, R is the radius of curvature, Th is the surface thickness, Nd is the refractive index of the material, Vd is the Abbe number of the material, the H direction represents the sagittal direction, and the V direction represents the meridional direction. The cylinder only has a curvature radius in the H direction, and the V direction The radius of curvature is infinite.

Table 2 below shows the aspherical coefficients of various orders in the receiving lens group 110 of the laser receiving system 100 provided in Embodiment 1 of the present application.

Table 3 below shows the system parameters of the receiving lens group 110 of the laser receiving system 100 provided in Embodiment 1 of the present application.

It can be seen from Table 3 that the focal length ratio of the receiving lens group 110 in the sagittal direction and the meridional direction satisfies:

EFLx/EFLy=25.18/12.913=1.95>1.2 can enlarge the size of the light spot in the sagittal direction, thereby avoiding damage to the detector 120, and in addition, the difficulty of assembly can be reduced.

Figure 14 is a defocus curve diagram of a receiving lens group of a laser receiving system provided in Embodiment 1 of the present application.

Specifically, it can be seen from Figure 14 that the modulation transfer function (MTF) of the receiving lens group 110 under different fields of view is greater than 0.6 in both the sagittal and meridional directions. The receiving lens group 110 has high imaging quality. .

Figure 15 is a distortion curve diagram of a receiving lens group of a laser receiving system provided in Embodiment 1 of the present application.

As shown in FIG. 15 , the optical distortion of the receiving lens group 110 meets the deformation difference requirements and has high imaging quality. Among them, the abscissa of the distortion curve is percentage, and the ordinate is numerical value.

Figure 16 is a spot diagram of the receiving lens group in the full field of view of a laser receiving system provided in Embodiment 1 of the present application.

As shown in FIG. 16 , the receiving lens group 110 can enlarge the size of the light spot in the sagittal direction. Among them, the IMA in the spot diagram is the real image height of each field of view.

Embodiment 2

Figure 17 is a schematic structural diagram of the receiving lens group provided in the second embodiment of the present application in the sagittal direction.

In this embodiment, referring to FIG. 17 , along the optical axis direction from the object side to the image side, the laser receiving system 100 includes a non-rotationally symmetric mirror group 111 , a rotationally symmetrical mirror group 112 and a detector 120 . In other words, the non-rotationally symmetric mirror group The non-rotationally symmetric lens group 111 is close to the object side, and the rotationally symmetric lens group 112 is close to the image side.

Referring to Figure 17, the non-rotationally symmetric lens group 111 includes two non-rotationally symmetric lenses 1111, and the two non-rotationally symmetric lenses 1111 are both cylindrical mirrors. In addition, the cylindrical surface closest to the object side of the two cylindrical mirrors is The object side of the mirror is convex, and the cylindrical mirror closest to the object side of the two cylindrical mirrors has positive power in the sagittal direction.

Referring to FIG. 17 , the rotationally symmetric lens group 112 includes four rotationally symmetric lenses 1121 and a plane mirror 1122 . Two of the four rotationally symmetrical lenses 1121 are aspherical mirrors, and the remaining two of the four rotationally symmetrical lenses 1121 are spherical mirrors. The use of spherical mirrors can reduce the difficulty of lens processing and help reduce manufacturing costs. The plane mirror 1122 is located between the detector 120 and the four rotationally symmetric mirrors 1121 .

The rotationally symmetrical lens 1121 closest to the object side among the four rotationally symmetrical lenses 1121 has positive optical power, and the object-side surface of the rotationally symmetrical lens 1121 closest to the object side among the four rotationally symmetrical lenses 1121 is convex.

The receiving lens group 110 also includes a filter 113 (refer to Figure 17), a diffractive optical element 115 (not shown in the figure) and a square aperture 116 (not shown in the figure). The filter 113 is located on two Between the cylindrical mirrors, they are used to filter stray light. The diffractive optical element 115 is disposed on a certain surface of any lens in the receiving lens group 110 .

The ratio of the focal length of the receiving lens group 110 in the sagittal direction to the focal length of the receiving lens group 110 in the meridional direction is:
EFLx/EFLy=24.505/13.003=1.885.

The angular magnification of the non-rotationally symmetric lens group 111 in the sagittal direction is 2.5.

The ratio of the image height of the receiving lens group 110 in the meridian direction to the focal length of the receiving lens group 110 in the meridian direction is: IHy/EFLy=6/13.003=0.46.

The ratio of the entrance pupil diameter of the laser receiving system 100 in the sagittal direction to the entrance pupil diameter of the laser receiving system 100 in the meridional direction is: EPDx/EPDy=12/12.8=0.9375.

The ratio of the lens diameter of the lens closest to the image side in the receiving lens group 110 to the image height of the receiving lens group 110 is:
D/IH=9.92/6=1.65.

The ratio of the focal length of the non-rotationally symmetric lens group 111 to the focal length of the rotationally symmetric lens group 112 is:
|EFL1/EFL2|=16780/13.003=1290.5.

Table 4 below shows the optical parameters of each lens in the receiving lens group 110 of a laser receiving system 100 provided in Embodiment 2 of the present application.

Among them, L1 is the first cylindrical mirror closest to the object side, L2 is the filter 113, L3 is the second cylindrical mirror closest to the image side, L4 is the first spherical mirror closest to the object side, and L5 is the second spherical mirror, L6 is the first aspherical mirror, L7 is the second aspherical mirror closest to the image side, and L8 is the plane mirror 1122.

Table 5 below shows the aspherical coefficients of various orders in the receiving lens group 110 of the laser receiving system 100 provided in Embodiment 2 of the present application.

The following Table 6 shows the system parameters of the receiving lens group 110 of a laser receiving system 100 provided in Embodiment 2 of the present application.

It can be seen from Table 6 that the focal length ratio of the receiving lens group 110 in the sagittal direction and the meridional direction satisfies:

EFLx/EFLy=24.505/13.003=1.885>1.2 can enlarge the size of the light spot in the sagittal direction, thereby avoiding damage to the detector 120, and in addition, the difficulty of assembly can be reduced.

Figure 18 is a defocus curve diagram of a receiving lens group of a laser receiving system provided in Embodiment 2 of the present application.

Specifically, it can be seen from Figure 18 that the modulation transfer function (MTF) of the receiving lens group 110 under different fields of view is greater than 0.5 in both the sagittal and meridional directions. The receiving lens group 110 has high imaging quality. .

Figure 19 is a distortion curve diagram of a receiving lens group of a laser receiving system provided in Embodiment 2 of the present application.

As shown in FIG. 19 , the optical distortion of the receiving lens group 110 meets the deformation difference requirements and has high imaging quality. Among them, the abscissa of the distortion curve is percentage, and the ordinate is numerical value.

Figure 20 is a spot diagram of the receiving lens group in the full field of view of a laser receiving system provided in Embodiment 2 of the present application.

As shown in FIG. 20 , the receiving lens group 110 can enlarge the size of the light spot in the sagittal direction. Among them, the IMA in the spot diagram is the real image height of each field of view.

Embodiment 3

Figure 21 is a schematic structural diagram of the receiving lens group provided in the third embodiment of the present application in the sagittal direction.

In this embodiment, referring to Figure 21, along the optical axis direction from the object side to the image side, the laser receiving system 100 includes a non-rotationally symmetric mirror group 111, a rotationally symmetrical mirror group 112 and a detector 120. In other words, the non-rotationally symmetrical mirror group The non-rotationally symmetric lens group 111 is close to the object side, and the rotationally symmetric lens group 112 is close to the image side.

21, the non-rotationally symmetric lens group 111 includes two non-rotationally symmetrical lenses 1111, and the two non-rotationally symmetrical lenses 1111 are both cylindrical mirrors. In addition, the cylindrical surface closest to the object side of the two cylindrical mirrors is The object side of the mirror is convex, and the cylindrical mirror closest to the object side of the two cylindrical mirrors has positive power in the sagittal direction.

Referring to FIG. 21 , the rotationally symmetric lens group 112 includes four rotationally symmetric lenses 1121 and a plane mirror 1122 . Two of the four rotationally symmetrical lenses 1121 are aspherical mirrors, and the remaining two of the four rotationally symmetrical lenses 1121 are spherical mirrors. The use of spherical mirrors can reduce the difficulty of lens processing and help reduce manufacturing costs. The plane mirror 1122 is located between the detector 120 and the four rotationally symmetric mirrors 1121 .

The receiving lens group 110 also includes a filter 113 (not shown in the figure), a diffractive optical element 115 (not shown in the figure) and a square aperture 116 (not shown in the figure). The filter 113 is located at Between two cylindrical mirrors, it is used to filter stray light. The diffractive optical element 115 is disposed on a certain surface of any lens in the receiving lens group 110 .

Referring to FIG. 21 , the receiving lens group 110 also includes a reflector 114 , which is disposed between two cylindrical mirrors to fold the optical path of the non-rotationally symmetric lens group 111 , thereby improving the compactness of the receiving lens group 110 .

The ratio of the focal length of the receiving lens group 110 in the sagittal direction to the focal length of the receiving lens group 110 in the meridional direction is:
EFLx/EFLy=24.105/12.932=1.885.

The angular magnification of the non-rotationally symmetric lens group 111 in the sagittal direction is 1.87.

The ratio of the image height of the receiving lens group 110 in the meridian direction to the focal length of the receiving lens group 110 in the meridian direction is: IHy/EFLy=6.006/12.932=0.464.

The ratio of the entrance pupil diameter of the laser receiving system 100 in the sagittal direction to the entrance pupil diameter of the laser receiving system 100 in the meridional direction is: EPDx/EPDy=12/12=1.

The ratio of the lens diameter of the lens closest to the image side in the receiving lens group 110 to the image height of the receiving lens group 110 is:
D/IH=8.76/6.003=1.46.

The ratio of the focal length of the non-rotationally symmetric lens group 111 to the focal length of the rotationally symmetric lens group 112 is:
|EFL1/EFL2|=597.66/12.932=46.22.

Table 7 below shows the optical parameters of each lens in the receiving lens group 110 of a laser receiving system 100 provided in Embodiment 3 of the present application.

Among them, L1 is the first cylindrical mirror closest to the object side, L2 is the reflector 114, L3 is the second cylindrical mirror closest to the image side, L4 is the filter 113, and L5 is the closest cylindrical mirror to the object side. The first spherical mirror, L6 is the second aspherical mirror, L7 is the first aspherical mirror, L8 is the second aspherical mirror closest to the image side, and L9 is the plane mirror 1122.

Table 8 below shows the aspherical coefficients of various orders in the receiving lens group 110 of a laser receiving system 100 provided in Embodiment 3 of the present application.

Table 9 below shows the system parameters of the receiving lens group 110 of a laser receiving system 100 provided in Embodiment 3 of the present application.

It can be seen from Table 9 that the focal length ratio of the receiving lens group 110 in the sagittal direction and the meridional direction satisfies:

EFLx/EFLy=24.105/12.932=1.885>1.2 can enlarge the size of the light spot in the sagittal direction, thereby avoiding damage to the detector 120, and in addition, the difficulty of assembly can be reduced.

Figure 22 is a defocus curve diagram of a receiving lens group of a laser receiving system provided in Embodiment 3 of the present application.

Specifically, it can be seen from Figure 22 that the modulation transfer function (MTF) of the receiving lens group 110 under different fields of view is greater than 0.7 in both the sagittal direction and the meridional direction. The receiving lens group 110 has high imaging quality. .

Figure 23 is a distortion curve diagram of a receiving lens group of a laser receiving system provided in Embodiment 3 of the present application.

As shown in FIG. 23 , the optical distortion of the receiving lens group 110 meets the deformation difference requirements and has high imaging quality. Among them, the abscissa of the distortion curve is percentage, and the ordinate is numerical value.

As shown in FIG. 24 , the receiving lens group 110 can enlarge the size of the light spot in the sagittal direction. Among them, the IMA in the spot diagram is the real image height of each field of view.

It should be noted that the numerical values and numerical ranges involved in the embodiments of the present application are approximate values, and there may be a certain range of errors. Those skilled in the art can consider these errors to be negligible.

In the description of the embodiments of this application, it should be noted that, unless otherwise clearly stated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection or a fixed connection. Indirect connection through an intermediary can be the internal connection between two elements or the interaction between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

The terms "first", "second", "third", "fourth", etc. (if present) in the description and claims of the embodiments of this application and the above-mentioned drawings are used to distinguish similar objects, and It is not necessary to describe a specific order or sequence.

Claims

A laser receiving system, characterized in that it includes: a receiving lens group and a detector that cooperates with the receiving lens group;

The detector is used to receive the laser light transmitted through the receiving lens group to form an image on the detection surface of the detector;

Along the optical axis direction from the object side to the image side, the receiving lens group includes a non-rotationally symmetric lens group and a rotationally symmetric lens group;

The rotationally symmetric lens group includes at least three rotationally symmetric lenses;

The non-rotationally symmetrical lens group includes at least one non-rotationally symmetrical lens;

The non-rotationally symmetric lens group is used to make the receiving lens group satisfy the conditional expression: EFLx/EFLy≥1.2, where EFLx is the focal length of the receiving lens group in the sagittal direction, and EFLy is the receiving lens group in the sagittal direction. Focal length in the meridian direction;

The angular magnification of the non-rotationally symmetric lens group in the sagittal direction is greater than 1.
The laser receiving system according to claim 1, wherein the lens in the receiving lens group closest to the object side has positive optical power in the sagittal direction.
The laser receiving system according to claim 1 or 2, characterized in that the receiving lens group satisfies the conditional expression: IHy/EFLy≥0.1, where IHy is the image height of the receiving lens group in the meridional direction, EFLy is the focal length of the receiving lens group in the meridian direction.
The laser receiving system according to any one of claims 1 to 3, characterized in that the receiving lens group satisfies the conditional expression: D/IH≥1, where D is the closest to the image in the receiving lens group. The lens diameter of the side lens, IH is the image height of the receiving lens group.
The laser receiving system according to any one of claims 1 to 4, characterized in that the receiving lens group satisfies the conditional expression: EFL1/EFL2≥1.5, where EFL1 is the focal length of the non-rotationally symmetric lens group, and EFL2 is The focal length of the rotationally symmetric lens group.
The laser receiving system according to any one of claims 1 to 5, characterized in that the laser receiving system satisfies the conditional expression: 0.2≤EPDx/EPDy≤5, where EPDx is the sagittal direction of the laser receiving system. The entrance pupil diameter on EPDy is the entrance pupil diameter of the laser receiving system in the meridional direction.
The laser receiving system according to any one of claims 1 to 6, characterized in that the at least one non-rotationally symmetric mirror is a cylindrical mirror or a free-form mirror.
The laser receiving system according to any one of claims 1 to 7, wherein the object side of the lens closest to the object side in the non-rotationally symmetric lens group is convex.
The laser receiving system according to any one of claims 1 to 8, characterized in that the non-rotationally symmetrical lens group includes at least two non-rotationally symmetrical lenses.
The laser receiving system according to claim 9, wherein the number of the at least two non-rotationally symmetric lenses is 2 to 4, and the material of the at least one non-rotationally symmetrical lens is plastic or glass.
The laser receiving system according to any one of claims 1 to 10, characterized in that the number of the at least three rotationally symmetrical lenses is 3 to 7; the rotationally symmetrical lens group includes any one of the following lenses Or two: aspheric mirror or spherical mirror; the material of the at least three rotationally symmetrical lenses is plastic or glass.
The laser receiving system according to any one of claims 1 to 11, characterized in that the rotationally symmetric mirror group is located between the non-rotationally symmetric mirror group and the detector.
The laser receiving system according to claim 12, wherein the lens closest to the object side in the rotationally symmetric lens group has positive optical power.
The laser receiving system according to any one of claims 1 to 13, wherein the object side of the lens closest to the object side in the rotationally symmetric lens group is a convex surface.
The laser receiving system according to any one of claims 1 to 14, characterized in that the receiving lens group further includes: at least one optical filter, the at least one optical filter is located in the non-rotationally symmetrical lens group .
The laser receiving system according to any one of claims 1 to 15, further comprising: at least one reflecting mirror, the at least one reflecting mirror is located in the receiving lens group and is used to deflect the light from the object side to the image. side light path.
The laser receiving system according to any one of claims 1 to 16, characterized in that at least one lens in the receiving lens group is provided with a diffractive optical element.
The laser receiving system according to any one of claims 1 to 17, characterized in that the receiving lens group further includes: The square aperture is located on the side of the receiving lens group facing the object side.
A lens assembly, characterized in that the lens assembly is the receiving lens group in the laser receiving system according to any one of claims 1-18.
A laser radar, characterized by comprising a laser transmitting system and a laser receiving system according to any one of claims 1-18.
An electronic device, characterized in that it includes a body and the laser radar according to claim 20, and the laser radar is installed on the body.
A vehicle, characterized in that it includes a vehicle body and the laser radar according to claim 20, the laser radar being installed on the vehicle body.