A lidar lens

Abstract

Embodiments of the present application disclose a kind of laser radar lens, the laser radar lens includes first lens, second lens, third lens, fourth lens and fifth lens in order along optical axis from object side to image side;Wherein, first lens is the free-form surface lens with positive focal power in X direction, with negative focal power in Y direction;Second lens has negative focal power;Third lens has positive focal power;Fourth lens has negative focal power;Fifth lens is the free-form surface lens with positive focal power in X direction and Y direction;The shape of first lens and fifth lens is different in XY section, so that laser radar lens produces different focal length in X direction and Y direction, XY section is perpendicular to optical axis, and X direction and Y direction cross.The laser radar lens provided by the embodiments of the present application has a large field of view ratio, and when matched with a 16:9 sensor, a field of view ratio of 48:10 or more can be generated, a wide-angle edge aperture is ≤2.5, and the imaging performance is excellent.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lenses, in particular to a laser radar lens. BACKGROUND

[0002] The laser radar is different from the traditional radar with microwave or millimeter wave as a carrier, and refers to the optical radar with laser as a carrier, a photoelectric detector as a receiver, and an optical lens as an antenna. The working principle is to emit a laser beam to a measured target, and then measure the arrival time, strength and other parameters of the reflected or scattered signal to determine the distance, direction, motion state and surface optical characteristics of the target, so as to establish the three-dimensional imaging information of the measured target. Due to the high detection accuracy, low power consumption, small size, and easy to equip, the laser radar has been widely used in topographic surveying, city modeling, industrial manufacturing, automatic driving, and early warning detection, guidance, and fuse, and has a good application prospect.

[0003] The laser radar lens generally hopes to have a wide horizontal field of view and a narrow vertical field of view, but the conventional lens is designed with a symmetrical optical structure, which will cause the horizontal and vertical field of view ratio to be close to the sensor, and modifying the sensor alone will affect its universality. SUMMARY

[0004] The embodiment of the present application provides a laser radar lens, which has a large field of view ratio, can produce a field of view ratio of more than 48:10 when matched with a 16:9 sensor, a wide-angle edge aperture is less than or equal to 2.5, and the imaging performance is excellent.

[0005] According to one aspect of the present application, a laser radar lens is provided, which comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in order along an optical axis from an object side to an image side.

[0006] The first lens is a free-form surface lens with positive focal power in the X direction and negative focal power in the Y direction; the second lens has negative focal power; the third lens has positive focal power; the fourth lens has negative focal power; the fifth lens is a free-form surface lens with positive focal power in the X direction and the Y direction; the shapes of the first lens and the fifth lens in the XY section are different, so that the laser radar lens produces different focal lengths in the X direction and the Y direction, the XY section is perpendicular to the optical axis, and the X direction and the Y direction intersect.

[0007] Optionally, the focal power of the first lens and the fifth lens satisfies:

[0008]

[0009]

[0010] wherein, represents the optical power of the first lens in the Y direction, represents the optical power of the first lens in the X direction, represents the optical power of the fifth lens in the Y direction, represents the optical power of the fifth lens in the X direction.

[0011] Optionally, the optical power of the laser radar lens satisfies:

[0012] 3.4≤Fx / Fy;

[0013] wherein, Fx represents the focal length of the laser radar lens in the X direction, and Fy represents the focal length of the laser radar lens in the Y direction.

[0014] Optionally, the optical power of the second lens and the fourth lens satisfies:

[0015]

[0016]

[0017] wherein, represents the optical power of the second lens, represents the optical power of the fourth lens, represents the overall optical power of the laser radar lens in the Y direction.

[0018] Optionally, the first lens and the fifth lens are plastic lenses.

[0019] Optionally, the refractive index of the first lens and the fifth lens satisfies:

[0020] 1.50≤n1≤1.70;

[0021] 1.51≤n5≤1.69;

[0022] wherein, n1 represents the refractive index of the first lens, and n5 represents the refractive index of the fifth lens.

[0023] Optionally, the second lens is a glass lens or a plastic lens, the third lens is a glass lens, and the fourth lens is a glass lens or a plastic lens.

[0024] Optionally, further comprising a diaphragm located between the second lens and the third lens.

[0025] Optionally, the field of view of the laser radar lens in the Y direction is greater than or equal to 48:10 of the field of view in the X direction.

[0026] Optionally, the field of view of the lidar lens in the Y direction is ≥120°, and the field of view of the lidar lens in the X direction is ≥25°.

[0027] The lidar lens provided in this invention includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the optical axis from the object side to the image side. The first lens is a freeform surface lens with positive optical power in the X direction and negative optical power in the Y direction; the second lens has negative optical power; the third lens has positive optical power; the fourth lens has negative optical power; and the fifth lens is a freeform surface lens with positive optical power in both the X and Y directions. By designing the first and fifth lenses as freeform surface lenses with different X and Y cross-sectional shapes, the lidar lens can generate different focal lengths in the X and Y directions, achieving different field-of-view ratios. Through reasonable matching of optical power, a field-of-view ratio of 48:10 or higher can be achieved when paired with a 16:9 sensor, with a wide-angle edge aperture ≤2.5.

[0028] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of a lidar lens in the X direction provided in an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of a lidar lens in the Y direction provided in an embodiment of the present invention;

[0032] Figure 3 An embodiment of the present invention provides a modulation transfer function (MTF) curve of a lidar lens;

[0033] Figure 4 This is a schematic diagram of another lidar lens structure in the X direction provided in an embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of another lidar lens structure in the Y direction provided in an embodiment of the present invention;

[0035] Figure 6Another MTF curve diagram of a laser radar lens provided by the embodiment of the present application is shown in FIG. 6.

[0036] Figure 7 Another structure schematic diagram of the X direction of a laser radar lens provided by the embodiment of the present application is shown in FIG. 7.

[0037] Figure 8 Another structure schematic diagram of the Y direction of a laser radar lens provided by the embodiment of the present application is shown in FIG. 8.

[0038] Figure 9 Another MTF curve diagram of a laser radar lens provided by the embodiment of the present application is shown in FIG. 6. DETAILED DESCRIPTION

[0039] In order to make the personnel in the art better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by the personnel in the art without creative labor should belong to the protection scope of the present application.

[0040] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be exchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to the clearly listed steps or units, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0041] Figure 1 A structure schematic diagram of the X direction of a laser radar lens provided by the embodiment of the present application is shown in FIG. 7. Figure 2 A structure schematic diagram of the Y direction of a laser radar lens provided by the embodiment of the present application is shown in FIG. 8. Figure 1 and Figure 2The laser radar lens provided by the embodiment of the application comprises, in sequence along an optical axis from an object side to an image side, a first lens 10, a second lens 20, a third lens 30, a fourth lens 40 and a fifth lens 50; wherein the first lens 10 is a free-form surface lens with positive focal power in the X direction and negative focal power in the Y direction; the second lens 20 has negative focal power, the object side of the second lens 20 is a concave surface, and the image side is a convex surface; the third lens 30 has positive focal power; the fourth lens 40 has negative focal power; the fifth lens 50 is a free-form surface lens with positive focal power in the X direction and the Y direction; the first lens 10 and the fifth lens 50 have different shapes in the XY section so as to produce different focal lengths of the laser radar lens in the X direction and the Y direction, the XY section is perpendicular to the optical axis (the optical axis is parallel to the Z direction), and the X direction and the Y direction intersect.

[0042] It can be understood that the focal power is the reciprocal of the focal length and represents the ability of an optical system to refract light. The greater the absolute value of the focal power, the stronger the ability to bend light, and the smaller the absolute value of the focal power, the weaker the ability to bend light. When the focal power is positive, the refraction of light is convergent; when the focal power is negative, the refraction of light is divergent. The first lens 10 and the fifth lens 50 are both free-form surface lenses, which can achieve different focal powers in the X direction and the Y direction. In the embodiment, the X direction refers to the direction in which the imaging field angle of the lens is small, and the Y direction refers to the direction in which the imaging field angle of the lens is large, so that the laser radar lens has different focal lengths and field angles in the X direction and the Y direction. The surfaces of the first lens 10 and the fifth lens 50 can be determined by the following polynomials, but are not limited to the following representations:

[0043] z=γ1×x 2 +γ2×x 4 +γ3×x 6 +γ4×x 8 +γ5×y 2 +γ6×y 4 +γ7×y 6 +γ8×y 8

[0044] wherein z is the axial height of the polynomial Z direction; x is the X direction height of the polynomial surface; y is the Y direction height of the polynomial surface; γ1-γ4 are respectively the 2nd, 4th, 6th and 8th order term coefficients of the polynomial X direction; and γ5-γ8 are respectively the 2nd, 4th, 6th and 8th order term coefficients of the polynomial Y direction.

[0045] The technical solution of this invention, by designing the first lens and the fifth lens as freeform surface lenses with different XY cross-sectional shapes, enables the lidar lens to generate different focal lengths in the X and Y directions, achieving different field-of-view ratios; by reasonably matching the optical power, it achieves a field-of-view ratio of more than 48:10 when paired with a 16:9 sensor, with a wide-angle edge aperture of ≤2.5.

[0046] Optionally, the lidar lens may also include an aperture stop ( Figure 1 and Figure 2 (Not shown), the aperture stop is located between the second lens 20 and the third lens 30. The aperture stop can filter out off-axis rays and improve the imaging effect.

[0047] Optionally, the optical power of the first lens 10 and the fifth lens 50 satisfies:

[0048]

[0049]

[0050] in, This indicates the optical power of the first lens 10 in the Y direction. This indicates the optical power of the first lens 10 in the X direction. This indicates the optical power of the fifth lens 50 in the Y direction. This indicates the optical power of the fifth lens 50 in the X direction.

[0051] When the optical power of the first lens 10 in the Y direction Optical power in the X direction The optical power of the fifth lens 50 in the Y direction Optical power in the X direction When the above conditions are met, the lens can achieve different focal lengths in the X and Y directions. Optionally, the optical power of the lidar lens should meet the following requirements:

[0052] 3.4 ≤ Fx / Fy;

[0053] Where Fx represents the focal length of the lidar lens in the X direction, and Fy represents the focal length of the lidar lens in the Y direction. Fx / Fy further achieves a larger ratio of field of view in both directions.

[0054] Optionally, the first lens 10 and the fifth lens 50 are both plastic lenses, the second lens 20 is a glass lens or a plastic lens, the third lens 30 is a glass lens, and the fourth lens 40 is a glass lens or a plastic lens.

[0055] By adopting the glass-plastic hybrid structure, the laser radar lens can realize a field of view ratio in the Y direction to that in the X direction ≥48:10, a wide-side field of view angle (field of view angle in the Y direction) ≥120°, and a narrow-side field of view angle (field of view angle in the X direction) ≥25° on a 16:9 sensor.

[0056] Optionally, the optical power of the second lens 20 and the fourth lens 40 satisfies:

[0057]

[0058]

[0059] wherein, represents the optical power of the second lens 20, represents the optical power of the fourth lens 40, represents the overall optical power of the laser radar lens in the Y direction.

[0060] By setting the optical power of the second lens 20 to satisfy the above condition, the light ray angle adjustment in the Y direction wide angle and the spherical aberration in the X direction small angle can be considered; by setting the optical power of the fourth lens 40 to satisfy the above condition, the light ray height can be adjusted to match a larger area receiver.

[0061] Optionally, the refractive index of the first lens 10 and the fifth lens 50 satisfies:

[0062] 1.50≤n1≤1.70;

[0063] 1.51≤n5≤1.69;

[0064] wherein, n1 represents the refractive index of the first lens 10, and n5 represents the refractive index of the fifth lens 50.

[0065] In the embodiment, the first lens 10 and the fifth lens 50 can use plastic materials, and the two lenses are more easily processed as polynomial surface non-rotational symmetric plastic materials. The refractive index in this range can match the shape to more easily make the X and Y direction focal lengths of the lens different, realize a large field of view ratio, and correct the light ray aberration.

[0066] In addition, some lenses in the embodiment of the application adopt aspheric lenses, and the surface of the aspheric lens satisfies the following formula:

[0067]

[0068] wherein, z is the axial height of the aspheric Z direction; r is the height of the aspheric surface; c is the curvature, that is, the reciprocal of the curvature radius; k is the conic coefficient; A-G are respectively the 4th order, 6th order, 8th order, 10th order, 12th order, 14th order and 16th order term coefficients of the aspheric polynomial.

[0069] Exemplarily, Table 1 is the specific parameters of the laser radar lens Figure 1 and Figure 2 The specific parameters of the corresponding laser radar lens are as follows:

[0070] Table 1 is the specific parameters of the laser radar lens

[0071] Example 1 Lower limit Upper limit φy1 -0.1155 φx1 0.0354 φy5 0.1197 φx5 0.0089 Fy 2.6782 F× 9.3983 φy1 / φx1 -3.2627 -3.6 -3.1 φy5 / φx5 13.4494 11 22 Fx / Fy 3.5092 3.4 φ2 -0.0152 φ4 -0.0364 φy 0.3734 φ2 / φy .0.0407 .0.065 .0.035 φ4 / φy .0.0975 .0.11 .0.05 n1 1.534 1.50 1.70 n5 1.54 1.51 1.69

[0072] Table 2 is the parameter data of each lens in Example 1, which can realize X direction focal length Fx=9.3983mm, Y direction focal length Fy=2.6782mm; X field of view angle 25°, Y field of view angle 130°.

[0073] Surface number Surface type Curvature radius Thickness Refractive index Abbe number k Half radius Y Half radius X 1 Polynomial / 1.325 1.534 55.7 5.14 4.0 2 Polynomial / 3.323 3.17 3.175 3 Asphere -3.2157 4.097 1.53 55.7 0 2.17 4 Asphere -4.2218 -0.290 0 1.58 5 STO Infinitv 0.496 1.58 6 Sphere 6.7447 0.936 1.713 53.9 2.01 7 Sphere 13.9639 1.350 2.11 8 Asphere -3.2619 3.393 1.63 23.5 0 2.14 9 Asphere -3.8004 3.427 0 3.59 10 Polynomial / 2.920 1.54 56 4.60 4.0 11 Polynomial / 2.000 4.66 4.0 12 Sphere Infinitv 0.500 1.52 64.2 3.93 13 Sphere Infinitv 2.499 3.87 14 Image surface Infinitv

[0074] Table 3 is a design value of the aspherical surface coefficient in the laser radar lens of Example 1

[0075]

[0076] Table 4 is a design value of the polynomial coefficient in the laser radar lens of Example 1

[0077]

[0078] The surface number in Tables 2, 3 and 4 is numbered according to the surface order of each lens, wherein "1" represents the front surface (object side surface) of the first lens 10, "2" represents the rear surface (image side surface) of the first lens 10, and the like, "12" and "13" represent the two surfaces of the lens protection glass; "STO" represents the diaphragm of the lens; the curvature radius represents the bending degree of the lens surface, the positive value represents that the surface is bent to the image side, and the negative value represents that the surface is bent to the object side; "Infinity" represents that the curvature radius is infinite, i.e. a plane; the thickness represents the center axis distance from the current surface to the next surface, the units of the curvature radius, the thickness and the half radius are millimeters; the refractive index represents the deflection ability of the material between the current surface and the next surface to the light, and the space represents that the current position is air with a refractive index of 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to the light, and the space represents that the current position is air; the k value represents the conic coefficient of the aspherical surface, wherein 8.04295E-03 represents that the A coefficient of the surface number 3 is 8.04295*10 -3 .

[0079] Figure 3 The modulation transfer function (MTF) curve of the laser radar lens provided in the embodiment of the application is shown in FIG. 2. Figure 3, the ordinate represents the MTF value, that is, the contrast, 0 represents no contrast, the larger the value, the better the resolution at this frequency, the maximum value of the ordinate is 1, which represents complete resolution, and has no unit; the abscissa represents the spatial frequency, that is, the number of line pairs contained per millimeter, and the unit is line pairs per millimeter (lp / mm). It can be shown from Figure 3 It can be shown from

[0080] Figure 4 Another structure schematic diagram of the laser radar lens in the X direction provided by the embodiment of the application is shown in Figure 5 Another structure schematic diagram of the laser radar lens in the Y direction provided by the embodiment of the application is shown in Table 5 is the specific parameters of the corresponding laser radar lens: Figure 4 and Figure 5 Table 5 is the specific parameters of the corresponding laser radar lens:

[0081] Table 5 is the specific parameters of the corresponding laser radar lens:

[0082] Example 2 Lower limit Upper limit φy1 -0.1276 φx1 0.0361 φy5 0.1306 φx5 0.0067 Fy 2.7100 Fx 9.4004 φy1 / φx1 .3.5346 .3.6 .3.1 φy5 / φx5 19.4925 11 22 Fx / Fy 3.4688 3.4 φ2 -0.0233 φ4 -0.0252 φy 0.3690 φ2 / φy -0.0631 -0.065 -0.035 φ4 / φy -0.0683 -0.11 -0.05 n1 1.69 1.50 1.70 n5 1.66 1.51 1.69

[0083] Table 6 is the parameter data of each lens in the second embodiment, and the second embodiment can realize X direction focal length Fx=9.4004 mm, Y direction focal length Fy=2.7100 mm; X field of view angle 25°, Y field of view angle 130°.

[0084] Surface number Surface type Curvature radius Thickness Refractive index Abbe number k Half radius Y Half radius X 1 Polynomial / 1.929 1.69 20.38 4.95 4.0 2 Polynomial / 2.853 2.96 2.96 3 Asphere -3.1943 4.047 1.66 20.38 0 1.99 4 Asphere -4.2614 -0.280 0 1.57 5 STO Infinitv 0380 1.56 6 Sphere 5.9308 0.929 1.71 53.87 1.92 7 Sphere 10.6664 1.214 2.01 8 Asphere -3.1981 3397 1.53 55.71 0 2.04 9 Asphere -3.7769 3.550 0 3.41 10 Polynomial / 2.980 1.66 20.38 4.59 3.50 11 Polynomial / 2.000 4.68 3.50 12 Sphere Infinitv 0.500 1.52 64.2 3.94 13 Sphere Infinitv 2.500 3.87 14 Image surface Infinitv

[0085] Table 7 is a design value of the aspheric surface coefficient of the laser radar lens in the second embodiment

[0086]

[0087] Table 8 is a design value of the polynomial coefficient of the laser radar lens in the second embodiment

[0088]

[0089] The surface sequence numbers in Tables 6, 7 and 8 are numbered according to the surface sequence of each lens, wherein "1" represents the front surface (object side surface) of the first lens 10, "2" represents the rear surface (image side surface) of the first lens 10, and so on, "12" and "13" represent the two surfaces of the lens protection glass; "STO" represents the aperture stop of the lens; the radius of curvature represents the bending degree of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side; "Infinity" represents that the radius of curvature is infinite, that is, a plane; the thickness represents the center axis distance from the current surface to the next surface, the units of the radius of curvature, the thickness and the half radius are millimeters; the refractive index represents the deflection ability of the material between the current surface and the next surface to the light, and the space represents that the current position is air with a refractive index of 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to the light, and the space represents that the current position is air; the k value represents the conic coefficient of the aspheric surface, wherein 8.26809E-03 represents that the A coefficient of the surface sequence number 3 is 8.26809E-03 -3 .

[0090] Figure 6 Another MTF curve diagram of the laser radar lens provided by the embodiment of the present application is shown in Figure 6 , wherein the vertical coordinate represents the MTF value, that is, the contrast, 0 represents no contrast, and the larger the value is, the better the resolution at the frequency is; the horizontal coordinate represents the spatial frequency, that is, the number of line pairs contained per millimeter, and the unit is line pairs per millimeter (lp / mm). It can be shown from Figure 6 that the embodiment can be matched with a receiver with a pixel size of 20 μm or more.

[0091] Figure 7 Another structure schematic diagram of the laser radar lens in the X direction provided by the embodiment of the present application is shown in Figure 8 Another structure schematic diagram of the laser radar lens in the Y direction provided by the embodiment of the present application is shown in Table 9 is the specific parameters of the laser radar lens corresponding to Figure 7 and Figure 8

[0092] Table 9 is the specific parameters of the laser radar lens

[0093] Example 3 Lower limit Upper limit φy1 -0.1284 φx1 0.0363 φy5 0.1297 φx5 0.0063 Fy 2.6954 Fx 9.3969 φy1 / φx1 -3.5372 -3.6 -3.1 φy5 / φx5 20.5873 11 22 Fx / Fy 3.4863 3.4 φ2 -0.0233 φ4 -0.0263 φy 0.3710 φ2 / φy -0.0628 -0.065 -0.035 φ4 / φy -0.0709 -0.11 -0.05 n1 1.68 1.50 1.70 n5 1.66 1.51 1.69

[0094] Table 10 is the parameter data of each lens in the third embodiment, and the third embodiment can realize an X direction focal length Fx=9.3969 mm, a Y direction focal length Fy=2.6954 mm, an X field of view angle of 25°, and a Y field of view angle of 130°.

[0095] Surface number Surface type Curvature radius Thickness Refractive index Abbe number k Half radius Y Half radius X 1 Polynomial / 1.929 1.68 20.4 4.98 4.00 2 Polynomial / 2.858 2.94 2.94 3 Asphere -3.1911 4.047 1.66 20.4 0 1.99 4 Asphere -4.2580 -0.270 0 1.57 5 STO Infinitv 0369 1.56 6 Sphere 5.9562 0.928 1.71 53.9 1.91 7 Sphere 10.6909 1.214 2.00 8 Asphere -3.2020 3.396 1.51 55.7 0 2.04 9 Asphere -3.7805 3.550 0 3.41 10 Polynomial / 2.980 1.66 20.4 4.58 3.50 11 Polynomial / 2.000 4.68 3.50 12 Sphere Infinitv 0.500 1.52 64.2 3.93 13 Sphere Infinitv 2.499 3.86 14 Image surface Infinitv

[0096] ​Table 11 is a design value of aspheric coefficients in the laser radar lens of Example 3

[0097]

[0098] Table 12 is a design value of polynomial coefficients in the laser radar lens of Example 3

[0099]

[0100] The surface numbers in Tables 10, 11 and 12 are numbered according to the surface order of each lens, wherein "1" represents the front surface (object side surface) of the first lens 10, "2" represents the rear surface (image side surface) of the first lens 10, and so on, "12" and "13" represent the two surfaces of the lens protection glass; "STO" represents the stop of the lens; the radius of curvature represents the bending degree of the lens surface, a positive value represents that the surface is bent towards the image side, and a negative value represents that the surface is bent towards the object side; "Infinity" represents that the radius of curvature is infinite, i.e. a plane; the thickness represents the center axis distance from the current surface to the next surface, the units of the radius of curvature, the thickness and the semi-diameter are millimeters; the refractive index represents the light deflection ability of the material between the current surface and the next surface, and a space represents that the current position is air with a refractive index of 1; the Abbe number represents the chromatic dispersion characteristics of the material between the current surface and the next surface, and a space represents that the current position is air; the k value represents the conic coefficient of the aspheric surface, wherein 8.24109E-03 represents that the A coefficient of the surface number 3 is 8.24109 x 10 -3 .

[0101] Figure 9 Another MTF curve diagram of the laser radar lens provided by the embodiment of the present application is shown in FIG. 6. Figure 9 The vertical coordinate represents the MTF value, i.e. the contrast, 0 represents no contrast, and the larger the value is, the better the resolution at the frequency is, the maximum value of the vertical coordinate is 1, representing complete resolution, and there is no unit; the horizontal coordinate represents the spatial frequency, i.e. the number of line pairs contained per millimeter, and the unit is line pairs per millimeter (lp / mm). It can be shown from Figure 9 that the embodiment can be matched with a receiver with a pixel size of 20 μm or more.

[0102] The above detailed description does not constitute a limitation on the protection scope of the present application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent replacement and improvement within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A lidar lens, characterized in that, The number of lenses with optical power is five, including a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the optical axis from the object side to the image side; The first lens is a freeform lens with positive optical power in the X direction and negative optical power in the Y direction; the second lens has negative optical power, with a concave object-side surface and a convex image-side surface; the third lens has positive optical power, with a convex object-side surface and a concave image-side surface; the fourth lens has negative optical power, with a concave object-side surface and a convex image-side surface; and the fifth lens is a freeform lens with positive optical power in both the X and Y directions. The first and fifth lenses have different shapes in their XY cross-sections to produce different focal lengths in the X and Y directions. The XY cross-section is perpendicular to the optical axis, and the X and Y directions intersect. The optical power of the first lens and the fifth lens satisfies: -3.6≤φy1 / φx1≤-3.1; 11≤φy5 / φx5≤22; Wherein, φy1 represents the optical power of the first lens in the Y direction, φx1 represents the optical power of the first lens in the X direction, φy5 represents the optical power of the fifth lens in the Y direction, and φx5 represents the optical power of the fifth lens in the X direction.

2. The lidar lens according to claim 1, characterized in that, The optical power of the lidar lens meets the following requirements: 3.4 ≤ Fx / Fy; Wherein, Fx represents the focal length of the lidar lens in the X direction, and Fy represents the focal length of the lidar lens in the Y direction.

3. The lidar lens according to claim 1, characterized in that, The optical power of the second lens and the fourth lens satisfies: -0.065 < φ2 / φy < -0.035; -0.110 < φ4 / φy < -0.05; Wherein, φ2 represents the optical power of the second lens, φ4 represents the optical power of the fourth lens, and φy represents the overall optical power of the lidar lens in the Y direction.

4. The lidar lens according to claim 1, characterized in that, Both the first lens and the fifth lens are plastic lenses.

5. The lidar lens according to claim 4, characterized in that, The refractive indices of the first lens and the fifth lens satisfy: 1.50≤n1≤1.70； 1.51≤n5≤1.69； Wherein, n1 represents the refractive index of the first lens, and n5 represents the refractive index of the fifth lens.

6. The lidar lens according to claim 4, characterized in that, The second lens is a glass lens or a plastic lens, the third lens is a glass lens, and the fourth lens is a glass lens or a plastic lens.

7. The lidar lens according to claim 1, characterized in that, It also includes an aperture stop, located between the second lens and the third lens.

8. The lidar lens according to claim 1, characterized in that, The ratio of the field of view of the lidar lens in the Y direction to the field of view in the X direction is ≥48:

10.

9. The lidar lens according to claim 8, characterized in that, The field of view of the lidar lens in the Y direction is ≥120°, and the field of view of the lidar lens in the X direction is ≥25°.

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