A lidar transmitting and receiving optical system

Abstract

This disclosure relates to the field of lidar technology, and in particular to a lidar transmitting and receiving optical system, including a transmitting lens group and a receiving lens group. The transmitting lens group includes a first lens, a second lens, and a third lens sequentially from the object side to the image side along a first optical axis. The receiving lens group includes a fourth lens, a fifth lens, and a sixth lens sequentially from the object side to the image side along a second optical axis. The first, second, fourth, and fifth lenses are glass spherical lenses, the third lens is a glass aspherical lens, and the sixth lens has the same structure as the third lens. The transmitting and receiving lens groups are made of glass, offering good reliability and structural stability, meeting the requirements for automotive applications. The use of structurally identical aspherical lenses in both the transmitting and receiving lens groups reduces costs.

Description

Technical Field

[0001] This disclosure relates to the field of lidar technology, and in particular to a lidar transmitting and receiving optical system. Background Technology

[0002] A lidar system is a radar system that uses laser beams to detect the position, velocity, and other characteristics of a target. Its working principle involves emitting a detection signal (laser beam) towards the target, then comparing the received signal reflected back from the target (target echo) with the emitted signal. After appropriate processing, relevant information about the target, such as its distance, can be obtained.

[0003] Vehicle-mounted LiDAR is the core of a vehicle's driver assistance system. The performance of the LiDAR's transmitting and receiving optical systems directly affects the overall performance of the vehicle-mounted LiDAR. Existing products present a contradiction between cost and optical performance; high performance comes at a high cost, while low cost results in poor performance. In addition, existing products have unstable structures, weak shock resistance, and are easily affected by vehicle vibrations. Summary of the Invention

[0004] To address the aforementioned problems, this disclosure provides a lidar transmitting and receiving optical system.

[0005] Specifically, the technical solution disclosed herein is:

[0006] A lidar transmitting and receiving optical system includes a transmitting lens group and a receiving lens group. The transmitting lens group includes a first lens, a second lens, and a third lens in sequence along a first optical axis from the object side to the image side. The receiving lens group includes a fourth lens, a fifth lens, and a sixth lens in sequence along a second optical axis from the object side to the image side. The first, second, fourth, and fifth lenses are glass spherical lenses, the third lens is a glass aspherical lens, and the sixth lens has the same structure as the third lens.

[0007] In one embodiment, each of the first to sixth lenses includes an object-side surface facing the corresponding object side and allowing imaging light to pass through, and an image-side surface facing the corresponding image side and allowing imaging light to pass through; the first lens has a negative refractive index, the object-side surface of the first lens is convex, and the image-side surface of the first lens is concave; the second lens has a positive refractive index, the object-side surface of the second lens is concave / convex, and the image-side surface of the second lens is convex; the third lens has a positive refractive index, the object-side surface of the third lens is convex, and the image-side surface of the third lens is convex; the transmitting lens group has only the first, second, and third lenses with refractive index; the fourth lens has a negative refractive index, the object-side surface of the fourth lens is convex, and the image-side surface of the fourth lens is concave; the fifth lens has a positive refractive index, the object-side surface of the fifth lens is concave / convex, and the image-side surface of the fifth lens is convex; the receiving lens group has only the fourth, fifth, and sixth lenses with refractive index.

[0008] In one embodiment, a first aperture is provided between the first lens and the second lens, and a second aperture is provided between the fourth lens and the fifth lens.

[0009] In one embodiment, it further includes a receiving - end sensor, and the size of the receiving - end sensor is 1 / 2.8 inches.

[0010] In one embodiment, the aperture coefficient of the receiving - end lens group is 1.4.

[0011] In one embodiment, the transmitting - end lens group and the receiving - end lens group satisfy: - 9.00 < f1 < 13.00, 13.00 < f2 < 15.00, 19.00 < f3 < 22.00, - 9.00 < f4 < 13.00, 13.00 < f5 < 15.00; where f1, f2, f,3, f4, f5 are the focal lengths of the first lens, the second lens, the third lens, the fourth lens, and the fifth lens respectively.

[0012] In one embodiment, the transmitting - end lens group and the receiving - end lens group satisfy: 1.00 < |f1 / f 发 |< 2.00, 1.00 < |f2 / f 发 |< 2.50, 2.00 < |f3 / f[[ID=IS]] 发 |< 3.50, 1.00 < |f4 / f 接 |< 2.00, 1.00 < |f5 / f 接 |< 2.50, 2.00 < |f6 / f 接 |< 3.50; where f 发 is the overall focal length of the transmitting - end lens group, f 接 is the overall focal length of the receiving - end lens group, and f1, f2, f3, f4, f5, f6 are the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens respectively.

[0013] In one embodiment, the transmitting - end lens group and the receiving - end lens group satisfy: - 0.50 < f1 / f2 < - 1.30, - 0.50 < f4 / f5 < - 1.3; where f1, f2, f4, f5 are the focal lengths of the first lens, the second lens, the fourth lens, and the fifth lens respectively.

[0014] In one embodiment, the transmitting - end lens group and the receiving - end lens group satisfy: nd2 > 1.80, nd5 > 1.80; where nd2 and nd5 are the nd refractive indices of the second lens and the fifth lens respectively. [[ID=ID=36]]

[0015] The beneficial technical effects of the present disclosure:

[0016] 1. The transmitting and receiving lens groups of the optical system disclosed herein are glass lens groups, which have good reliability and stability, and meet the requirements of automotive applications. 2. Because the transmitting and receiving lens groups use aspherical lenses with the same structure, the optical system disclosed herein has a lower cost compared to existing technologies that use aspherical lenses with different structures in the transmitting and receiving lens groups. Attached Figure Description

[0017] Figure 1 This is a structural diagram of the transmitting lens assembly in Embodiment 1;

[0018] Figure 2 for Figure 1 Point diagram of the lens group;

[0019] Figure 3 for Figure 1 Field curvature and distortion diagram of the lens group;

[0020] Figure 4 for Figure 1 Relative illumination diagram of the lens group;

[0021] Figure 5 This is a structural diagram of the receiving lens assembly in Embodiment 1;

[0022] Figure 6 for Figure 5 Point diagram of the lens group;

[0023] Figure 7 for Figure 5 MTF curve of the lens group at 25℃;

[0024] Figure 8 for Figure 5 MTF curve of the lens group at -40℃;

[0025] Figure 9 for Figure 5 MTF curve of the lens group at 130℃;

[0026] Figure 10 for Figure 5 Field curvature and distortion diagram of the lens group;

[0027] Figure 11 for Figure 5 Relative illumination diagram of the lens group;

[0028] Figure 12 This is a structural diagram of the transmitting lens assembly in Embodiment 2;

[0029] Figure 13 for Figure 12 Point diagram of the lens group;

[0030] Figure 14 for Figure 12 Field curvature and distortion diagram of the lens group;

[0031] Figure 15 for Figure 12 Relative illumination diagram of the lens group;

[0032] Figure 16 This is a structural diagram of the receiving lens assembly in Embodiment 2;

[0033] Figure 17 for Figure 16 Point diagram of the lens group;

[0034] Figure 18 for Figure 16 MTF curve of the lens group at 25℃;

[0035] Figure 19 for Figure 16 MTF curve of the lens group at -40℃;

[0036] Figure 20 for Figure 16 MTF curve of the lens group at 130℃;

[0037] Figure 21 for Figure 16 Field curvature and distortion diagram of the lens group;

[0038] Figure 22 for Figure 16 Relative illumination diagram of the lens group. Detailed Implementation

[0039] The phrase "a lens with positive (or negative) refractive index" refers to a lens whose paraxial refractive index, calculated using Gaussian optics theory, is positive (or negative). The "object-side surface (or image-side surface)" is defined as the specific area through which imaging rays pass on the lens surface. The convexity or concavity of a lens surface can be determined using methods commonly employed in the field, namely by the sign of the radius of curvature (R-value). R-values ​​are commonly used in optical design software such as Zemax or CodeV. R-values ​​are also frequently found in lens data sheets within optical design software. For the object-side surface, a positive R-value indicates a convex surface, while a negative R-value indicates a concave surface. Conversely, for the image-side surface, a positive R-value indicates a concave surface, while a negative R-value indicates a convex surface.

[0040] This disclosure provides a lidar transmitting and receiving optical system, the optical system including a transmitting lens group and a receiving lens group. The transmitting lens group includes a first lens, a second lens and a third lens in sequence along a first optical axis from the object side to the image side. The receiving lens group includes a fourth lens, a fifth lens and a sixth lens in sequence along a second optical axis from the object side to the image side. The first lens, the second lens, the fourth lens and the fifth lens are glass spherical lenses, the third lens is a glass aspherical lens, and the sixth lens has the same structure as the third lens.

[0041] To ensure reliability and dependability, both the transmitter and receiver lens assemblies employ an all-glass design, resulting in a stable structure that meets automotive application requirements. Furthermore, to reduce costs, the optical design of both the transmitter and receiver lens assemblies is based on the premise that the aspherical lenses in both assemblies have the same structure, achieving a balance between optical system performance and cost.

[0042] Each of the first to sixth lenses includes an object-side surface facing the corresponding object side and through which imaging light passes, and an image-side surface facing the corresponding image side and through which imaging light passes. Preferably, the first lens has a negative refractive index, the object-side surface of the first lens is convex near the optical axis, and the image-side surface of the first lens is concave near the optical axis; the second lens has a positive refractive index, the object-side surface of the second lens is concave / convex near the optical axis, and the image-side surface of the second lens is convex near the optical axis; the third lens has a positive refractive index, the object-side surface of the third lens is concave / convex near the optical axis... The first, second, and third lenses in the transmitting lens group have refractive power. The fourth lens has negative refractive power, with its object-side surface convex near the optical axis and its image-side surface concave near the optical axis. The fifth lens has positive refractive power, with its object-side surface concave / convex near the optical axis and its image-side surface convex near the optical axis. The receiving lens group has refractive power only consisting of the fourth, fifth, and sixth lenses.

[0043] Preferably, a first aperture stop is provided between the first lens and the second lens, and a second aperture stop is provided between the fourth lens and the fifth lens. The aperture stops being located in the above positions are beneficial to improving the resolution of the lens group.

[0044] The optical system also includes a receiver sensor. Preferably, the receiver sensor is 1 / 2.8 inches in size and is designed for the pixel size of mainstream laser receiver TDC chips to meet the requirements of high resolution and ensure signal reception quality.

[0045] Preferably, the aperture coefficient of the receiving end lens group is 1.4. The larger aperture allows for more light to enter, resulting in high light spot uniformity and low noise interference.

[0046] Preferably, to improve the system performance and optimize the back focal shift after high and low temperature, the transmitting lens group and the receiving lens group satisfy: -9.00 < f1 < 13.00, 13.00 < f2 < 15.00, 19.00 < f3 < 22.00, -9.00 < f4 < 13.00, 13.00 < f5 < 15.00, 19.00 < f6 < 22.00; where f1, f2, f3, f4, f5, and f6 are the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens, respectively.

[0047] Preferably, to improve the system performance and optimize the back focal shift after high and low temperature, the transmitting lens group and the receiving lens group satisfy: 1.00 < |f1 / f 发 | < 2.00, 1.00 < |f2 / f 发 | < 2.50, 2.00 < |f3 / f 发 | < 3.50, 1.00 < |f4 / f 接 | < 2.00, 1.00 < |f5 / f 接 | < 2.50, 2.00 < |f6 / f 接 | < 3.50; where f 发 is the overall focal length of the transmitting lens group, and f 接 is the overall focal length of the receiving lens group.

[0048] Preferably, the transmitting lens group and the receiving lens group satisfy: -0.50 < f1 / f2 < -1.30, -0.50 < f4 / f5 < -1.30, to control the back focal shift under high and low temperature.

[0049] Preferably, the transmitting lens group and the receiving lens group satisfy: nd2 > 1.80, nd5 > 1.80; where nd2 and nd5 are the nd refractive indices of the second lens and the fifth lens, respectively. The second lens and the fifth lens are made of high refractive index materials, which is beneficial to reducing the aperture and the outer diameter.

[0050] The present disclosure will be described in detail below with reference to specific embodiments.

[0051] Embodiment 1:

[0052] A lidar transmitting and receiving optical system includes a transmitting lens group and a receiving lens group. As Figure 1 shown, the transmitting lens group includes, in sequence along the first optical axis I1 from its object side A11 to its image side A12, a first lens 1, a second lens 2, and a third lens 3, as Figure 5As shown, the receiving lens group includes a fourth lens 5, a fifth lens 6, and a sixth lens 7 sequentially along the second optical axis I2 from its object side A21 to its image side A22; the first lens 1, the second lens 2, the fourth lens 5, and the fifth lens 6 are glass spherical lenses, the third lens 3 is a glass aspherical lens, and the sixth lens 7 has the same structure as the third lens 3.

[0053] like Figure 1 As shown, the first lens 1, the second lens 2 and the third lens 3 each include an object-side surface facing the object side A11 and through which imaging light passes, and an image-side surface facing the image side A12 and through which imaging light passes.

[0054] In this embodiment, the first lens 1 has a negative refractive index, the object-side surface 11 of the first lens 1 is convex, and the image-side surface 12 of the first lens 1 is concave; the second lens 2 has a positive refractive index, the object-side surface 21 of the second lens 2 is convex, and the image-side surface 22 of the second lens 2 is convex; the third lens 3 has a positive refractive index, the object-side surface 31 of the third lens 3 is convex, and the image-side surface 32 of the third lens 3 is convex; the only lenses with refractive index in the emitting lens group are the first lens 1, the second lens 2, and the third lens 3.

[0055] like Figure 5 As shown, the fourth lens 5, the fifth lens 6 and the sixth lens 7 each include an object-side surface facing the object side A21 and through which imaging light passes, and an image-side surface facing the image side A22 and through which imaging light passes.

[0056] In this embodiment, the fourth lens 5 has a negative refractive index, the object-side surface 51 of the fourth lens 5 is convex, and the image-side surface 52 of the fourth lens 5 is concave; the fifth lens 6 has a positive refractive index, the object-side surface 61 of the fifth lens 6 is convex, and the image-side surface 62 of the fifth lens 6 is convex; the sixth lens 7 has the same structure as the third lens 3; the receiving end lens group has only the fourth lens 5, the fifth lens 6, and the sixth lens 7 with refractive index.

[0057] like Figure 1 As shown, a first aperture 4 is provided between the first lens 1 and the second lens 2, and a second aperture 8 is provided between the fourth lens 5 and the fifth lens 6.

[0058] Detailed optical data of the transmitter in this specific embodiment are shown in Table 1-1.

[0059] Table 1-1

[0060] surface Radius of curvature (mm) Thickness / Spacing (mm) Material Refractive index Dispersion coefficient Focal length (mm) 11 First lens 15.93 1.50 Glass 1.67 32.17 -10.64 12 4.66 4.36 4 Aperture Infinity 4.67 21 Second lens 402.74 4.44 Glass 1.85 23.78 14.29 22 -11.95 3.88 31 Third lens 14.70 6.50 Glass 1.59 59.57 20.07 32 -45.82 9.64

[0061] Detailed optical data of the receiver in this specific embodiment are shown in Table 1-2.

[0062] Table 1-2

[0063] surface Radius of curvature (mm) Thickness / Spacing (mm) Material Refractive index Dispersion coefficient Focal length (mm) 51 Fourth lens 14.71 3.68 Glass 1.67 32.17 -11.79 52 4.56 4.01 8 Aperture Infinity 4.79 61 Fifth lens 4838.81 5.01 Glass 1.85 23.78 14.19 62 -11.60 1.50 71 Sixth lens 14.70 6.50 Glass 1.59 59.57 20.07 72 -45.82 9.61

[0064] The aspherical coefficients of the object side 31 and image side 32 of the third lens 3 are shown in Table 1-3.

[0065] Table 1-3

[0066] surface 31 32 k 1.13E+00 -2.45E+00 <![CDATA[A2]]> 5.28E-05 2.54E-04 <![CDATA[A4]]> -3.39E-06 9.55E-07 <![CDATA[A6]]> 9.91E-08 1.96E-08 <![CDATA[A8]]> -1.30E-09 -1.48E-09

[0067] The formula for aspherical surfaces is as follows:

[0068]

[0069] Where r is the distance from a point on the optical surface to the optical axis, z is the sag of the point along the optical axis, c is the curvature of the surface, k is the quadratic constant of the surface, and A2, A4, A6, and A8 are the second, fourth, sixth, and eighth order aspheric coefficients, respectively.

[0070] The aspherical coefficients of the object side 71 and image side 72 of the sixth lens 7 are shown in Table 1-4.

[0071] Table 1-4

[0072] surface 71 72 k 1.13E+00 -2.45E+00 <![CDATA[A2]]> 5.28E-05 2.54E-04 <![CDATA[A4]]> -3.39E-06 9.55E-07 <![CDATA[A6]]> 9.91E-08 1.96E-08 <![CDATA[A8]]> -1.30E-09 -1.48E-09

[0073] The numerical values ​​of the relevant conditional expressions in this specific embodiment are shown in Tables 1-5.

[0074] Table 1-5

[0075]

[0076] In this specific embodiment, the lens group of the transmitter has a focal length of f = 7.25mm, an aperture of FNO = 1.6, a field of view (FOV) of 51°, an image height (IMH) of 6.4mm, and a total optical length (TTL) of 34.99mm.

[0077] The receiver lens group has a focal length of f = 7.38mm, an aperture of FNO = 1.4, a field of view of FOV = 51°, an image height of IMH = 6.5mm, and a total length of TTL = 35.10mm.

[0078] Figure 2 This is a dot plot of the transmitting lens group in this embodiment, with units in micrometers. Figure 2 As shown, the emitter lens group exhibits good speckle control at wavelengths from 930nm to 950nm. Figure 3 As shown, the transmitting lens group exhibits good field curvature and distortion control at wavelengths from 930nm to 950nm. Figure 4 As shown, the relative illuminance of the emitting lens group at a wavelength of 950nm is greater than 0.9.

[0079] Figure 6This is a dot plot of the receiving lens group in this embodiment, with units in micrometers. Figure 6 As shown, the receiver lens group exhibits good speckle control at wavelengths from 930nm to 950nm. Figures 7 to 9 As shown, at low temperatures of 25℃ and -40℃, and high temperatures of 130℃, the receiving lens group exhibits good performance with an OTF mode greater than 0.65 at wavelengths from 930nm to 950nm. Figure 10 As shown, the receiving lens group exhibits good field curvature and distortion control at wavelengths from 930nm to 950nm. Figure 11 As shown, the relative illuminance of the receiving lens group at a wavelength of 950nm is greater than 0.9.

[0080] Example 2:

[0081] like Figure 12 , 16 As shown, the differences between this embodiment and Embodiment 1 are as follows:

[0082] In this embodiment, the object-side surface 21 of the second lens 2 is concave, and the object-side surface 61 of the fifth lens 6 is concave. Furthermore, the parameters such as the radius of curvature, thickness, and focal length in this embodiment differ from those in Embodiment 1.

[0083] Detailed optical data of the transmitter in this specific embodiment are shown in Table 2-1.

[0084] Table 2-1

[0085]

[0086] Detailed optical data of the receiver in this specific embodiment are shown in Table 2-2.

[0087] Table 2-2

[0088]

[0089] The aspherical coefficients of the object side 31 and image side 32 of the third lens 3 are shown in Table 2-3.

[0090] Table 2-3

[0091] surface 31 32 k 1.10E+00 6.83E+00 <![CDATA[A2]]> 5.52E-05 2.48E-04 <![CDATA[A4]]> -3.23E-06 1.78E-06 <![CDATA[A6]]> 9.34E-08 -1.67E-08 <![CDATA[A8]]> -1.25E-09 -1.57E-09

[0092] The aspherical coefficients of the object side 71 and image side 72 of the sixth lens 7 are shown in Table 2-4.

[0093] Table 2-4

[0094] surface 71 72 k 1.10E+00 6.83E+00 <![CDATA[A2]]> 5.52E-05 2.48E-04 <![CDATA[A4]]> -3.23E-06 1.78E-06 <![CDATA[A6]]> 9.34E-08 -1.67E-08 <![CDATA[A8]]> -1.25E-09 -1.57E-09

[0095] The numerical values ​​of the relevant conditional expressions in this specific embodiment are shown in Table 2-5.

[0096] Table 2-5

[0097]

[0098] In this specific embodiment, the transmitting lens group has a focal length of f = 7.25mm, an aperture of FNO = 1.6, a field of view (FOV) of 51°, an image height (IMH) of 6.4mm, and a total length (TTL) of 34.99mm. The receiving lens group has a focal length of f = 7.38mm, an aperture of FNO = 1.4, a field of view (FOV) of 51°, an image height (IMH) of 6.5mm, and a total length (TTL) of 34.88mm.

[0099] Figure 13 This is a dot plot of the transmitting lens group in this embodiment, with units in micrometers. Figure 13 As shown, the emitter lens group exhibits good speckle control at wavelengths from 930nm to 950nm. Figure 14 As shown, the transmitting lens group exhibits good field curvature and distortion control at wavelengths from 930nm to 950nm. Figure 15 As shown, the relative illuminance of the emitting lens group at a wavelength of 950nm is greater than 0.9.

[0100] Figure 17 This is a dot plot of the receiving lens group in this embodiment, with units in micrometers. Figure 17 As shown, the receiver lens group exhibits good speckle control at wavelengths from 930nm to 950nm. Figures 18 to 20 As shown, at low temperatures of 25℃ and -40℃, and high temperatures of 130℃, the receiving lens group exhibits good performance with an OTF mode greater than 0.6 at wavelengths from 930nm to 950nm. Figure 21 As shown, the receiving lens group exhibits good field curvature and distortion control at wavelengths from 930nm to 950nm. Figure 22 As shown, the relative illuminance of the receiving lens group at a wavelength of 950nm is greater than 0.9.

[0101] The above description is merely a preferred embodiment of this disclosure and is not intended to limit the scope of this disclosure. It should be noted that any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of this disclosure after reading this specification should be included within the protection scope of this disclosure.

Claims

1. A laser radar transmitting and receiving optical system, comprising a transmitting lens group and a receiving lens group, characterized in that: The transmitting end lens group sequentially includes a first lens, a second lens, and a third lens along the first optical axis from its object side to its image side, and the receiving end lens group sequentially includes a fourth lens, a fifth lens, and a sixth lens along the second optical axis from its object side to its image side; the first lens, the second lens, the fourth lens, and the fifth lens are glass spherical lenses, the third lens is a glass aspherical lens, and the sixth lens has the same structure as the third lens; Each of the first lens to the sixth lens includes an object side surface facing the corresponding object side and allowing imaging light to pass through and an image side surface facing the corresponding image side and allowing imaging light to pass through; The first lens has a negative refractive power, the object side surface of the first lens is convex, and the image side surface of the first lens is concave; the second lens has a positive refractive power, the object side surface of the second lens is concave / convex, and the image side surface of the second lens is convex; the third lens has a positive refractive power, the object side surface of the third lens is convex, and the image side surface of the third lens is convex; the lenses with refractive power in the transmitting end lens group are only the first lens, the second lens, and the third lens; The fourth lens has a negative refractive power, the object side surface of the fourth lens is convex, and the image side surface of the fourth lens is concave; the fifth lens has a positive refractive power, the object side surface of the fifth lens is concave / convex, and the image side surface of the fifth lens is convex; the lenses with refractive power in the receiving end lens group are only the fourth lens, the fifth lens, and the sixth lens.

2. The laser radar transmitting and receiving optical system as described in claim 1, characterized in that: A first aperture stop is provided between the first lens and the second lens, and a second aperture stop is provided between the fourth lens and the fifth lens.

3. The laser radar transmitting and receiving optical system as described in claim 1, characterized in that: It further includes a receiving end sensor, and the size of the receiving end sensor is 1 / 2.8 inches.

4. The laser radar transmitting and receiving optical system as described in claim 1, characterized in that: The aperture coefficient of the receiving end lens group is 1.

4.

5. The laser radar transmitting and receiving optical system as described in claim 1, characterized in that, The transmitting end lens group and the receiving end lens group satisfy: -9.00 < f1 < 13.00, 13.00 < f2 < 15.00, 19.00 < f3 < 22.00, -9.00 < f4 < 13.00, 13.00 < f5 < 15.00; where f1, f2, f3, f4, f5 are the focal lengths of the first lens, the second lens, the third lens, the fourth lens, and the fifth lens respectively.

6. The laser radar transmitting and receiving optical system as described in claim 1, characterized in that, The transmitting lens group and the receiving lens group satisfy: 1.00 < |f1 / f 发 |<2.00, 1.00<|f2 / f 发 |<2.50, 2.00<|f3 / f 发 |<3.50, 1.00<|f4 / f 接 |<2.00, 1.00<|f5 / f 接 |<2.50, 2.00<|f6 / f 接 |<3.50; where f 发 f is the overall focal length of the transmitting lens group. 接 Let f1 be the overall focal length of the receiving lens group, and f2 be the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens, respectively.

7. The lidar transmitting and receiving optical system as described in claim 1, characterized in that, The transmitting end lens group and the receiving end lens group satisfy: -0.50 < f1 / f2 < -1.30, -0.50 < f4 / f5 < -1.30; where f1, f2, f4, f5 are the focal lengths of the first lens, the second lens, the fourth lens, and the fifth lens respectively.

8. The laser radar transmitting and receiving optical system as described in claim 1, characterized in that, The transmitting end lens group and the receiving end lens group satisfy: nd2 > 1.80, nd5 > 1.80; where nd2 and nd5 are the nd refractive indices of the second lens and the fifth lens respectively.

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