Laser radar and transmitting lens and receiving lens for laser radar

Abstract

This application discloses a lidar, including a transmitting lens and a receiving lens. The transmitting lens includes a first lens, a second lens, and a third lens arranged sequentially along the optical axis transmission direction. The first lens and the third lens are both meniscus positive lenses with their concave surfaces facing the laser side, and the second lens is a meniscus negative lens with its convex surface facing the laser side. The receiving lens includes a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis transmission direction. The fourth lens is a meniscus positive lens with its convex surface facing the object side, the fifth lens is a biconcave lens, the sixth lens is a biconvex lens, and the seventh lens is a meniscus negative lens with its convex surface facing the object side. Using the above-described lidar, the number of lenses in both the transmitting and receiving lenses is reduced, resulting in a compact structure and improved internal space utilization.

Description

Technical Field

[0001] This application belongs to the field of lidar technology, specifically relating to a lidar and a transmitting lens and a receiving lens for lidar. Background Technology

[0002] With the continuous development of intelligent driving technology, automobiles are gradually transforming from traditional transportation tools into more advanced intelligent products. LiDAR, as a mainstream sensor for intelligent driving in automobiles, has broad development prospects in fields such as civilian vehicles and industrial automation. LiDAR has advantages such as high precision, high resolution, and long detection range. Its working principle is to emit a laser of a specific wavelength into the detection area, and then compare the reflected laser with the emitted laser to obtain the geometric and motion information of objects in the detected area. Existing LiDAR lenses typically have a large number of lenses. Summary of the Invention

[0003] The technical problem to be solved by this application is that existing lidar lenses have a large number of lenses. To solve this technical problem, a lidar and a transmitting lens and a receiving lens for the lidar are provided.

[0004] The technical solution proposed in this application is as follows:

[0005] A transmitting lens for a lidar includes a first lens, a second lens, and a third lens arranged sequentially along the optical axis transmission direction. The first lens and the third lens are both meniscus positive lenses with their concave surfaces facing the laser side, and the second lens is a meniscus negative lens with its convex surface facing the laser side.

[0006] Furthermore, the air gap between the laser and the first lens on the optical axis is 4.93 mm, the air gap between the first lens and the second lens on the optical axis is 4.13 mm, and the air gap between the second lens and the third lens on the optical axis is 12.96 mm.

[0007] Furthermore, the first lens has a center thickness of 2.7 mm, a radius of curvature of -33.88 mm on the laser-facing side surface, and a radius of curvature of -12.9 mm on the laser-removing side surface; the second lens has a center thickness of 4.13 mm, a radius of curvature of 15.56 mm on the laser-facing side surface, and a radius of curvature of 8 mm on the laser-removing side surface; and the third lens has a center thickness of 3 mm, a radius of curvature of -36 mm on the laser-facing side surface, and a radius of curvature of -13.24 mm on the laser-removing side surface.

[0008] Furthermore, the total optical length (TTL), effective focal length (EFL), emission angle, and maximum optical distortion (Distmax) of the transmitting lens satisfy the following conditions:

[0009] 28mm < TTL < 31mm, 25mm < EFL < 29mm, emission angle is -10.79°~10.79°, Distmax < 1.8%.

[0010] A receiving lens for lidar, matched with a transmitting lens for lidar as described above, wherein the transmitting lens and the receiving lens are for light with a dominant wavelength of 905 nm.

[0011] Furthermore, the receiving lens includes a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis transmission direction. The fourth lens is a positive meniscus lens with its convex surface facing the object side, the fifth lens is a biconcave lens, the sixth lens is a biconvex lens, and the seventh lens is a negative meniscus lens with its convex surface facing the object side.

[0012] Furthermore, the air gap between the fourth lens and the fifth lens on the optical axis is 2.02 mm, the air gap between the fifth lens and the sixth lens on the optical axis is 3.06 mm, the air gap between the sixth lens and the seventh lens on the optical axis is 2.54 mm, and the air gap between the seventh lens and the image plane on the optical axis is 4.61 mm.

[0013] Furthermore, the fourth lens has a center thickness of 3.72 mm, an object-side radius of curvature of 13.64 mm, and an image-side radius of curvature of 79.49 mm; the fifth lens has a center thickness of 3 mm, an object-side radius of curvature of -22.72 mm, and an image-side radius of curvature of 20.59 mm; the sixth lens has a center thickness of 4 mm, an object-side radius of curvature of 30.25 mm, and an image-side radius of curvature of -14.63 mm; and the seventh lens has a center thickness of 4 mm, an object-side radius of curvature of 11.48 mm, and an image-side radius of curvature of 7.66 mm.

[0014] Furthermore, the total optical length (TTL), effective focal length (EFL), field of view (FOV), and maximum optical distortion (Distmax) of the receiving lens satisfy the following conditions:

[0015] TTL < 31mm, 15mm < EFL < 18mm, FOV is -10.5° to 10.5°, Distmax < 0.2%.

[0016] A lidar includes a transmitting lens for lidar as described above and a receiving lens for lidar as described above.

[0017] The aforementioned lidar uses fewer lenses for both the transmitting and receiving lenses, resulting in a compact structure and improved internal space utilization. Attached Figure Description

[0018] The accompanying drawings are provided to further understand this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof.

[0019] Figure 1 A schematic diagram of the structure of a transmitting lens for a lidar provided in an embodiment of this application;

[0020] Figure 2 for Figure 1 The diagram shown is a dot plot of the transmitting lens corresponding to different fields of view in an environment of 20°C.

[0021] Figure 3 for Figure 1 The diagram shows the dot plot of the transmitting lens under different fields of view in an environment of -40℃.

[0022] Figure 4 for Figure 1 The diagram shows the dot plot of the transmitting lens corresponding to different fields of view at 125°C.

[0023] Figure 5 for Figure 1 A schematic diagram of the field curvature and distortion of the transmitting lens;

[0024] Figure 6 A schematic diagram of the structure of a receiving lens for a lidar provided in an embodiment of this application;

[0025] Figure 7 for Figure 6 The diagram shows the dot plot of the receiving lens corresponding to different fields of view in a 20°C environment;

[0026] Figure 8 for Figure 6 The diagram shows the dot plot of the receiving lens corresponding to different fields of view in an environment of -40℃.

[0027] Figure 9 for Figure 6 The diagram shows the dot plot of the receiving lens corresponding to different fields of view at 125°C.

[0028] Figure 10 for Figure 6 The diagram shows the field curvature and distortion of the receiving lens.

[0029] Label Explanation:

[0030] 11. First lens; 12. Second lens; 13. Third lens; 21. Fourth lens; 22. Fifth lens; 23. Sixth lens; 24. Seventh lens. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0032] This application provides a lidar system including a transmitting lens and a receiving lens, which are matched to each other to detect the geometric and motion information of an object. Figure 1 and Figure 6 As shown, the transmitting lens includes a first lens, a second lens, and a third lens arranged sequentially along the optical axis transmission direction. The first and third lenses are both meniscus positive lenses with their concave surfaces facing the laser side, and the second lens is a meniscus negative lens with its convex surface facing the laser side. The receiving lens includes a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis transmission direction. The fourth lens is a meniscus positive lens with its convex surface facing the object side, the fifth lens is a biconcave lens, the sixth lens is a biconvex lens, and the seventh lens is a meniscus negative lens with its convex surface facing the object side.

[0033] In one embodiment, the total optical length (TTL), effective focal length (EFL), maximum optical distortion (Distmax), and exit angle or field of view (FOV) of the transmitting and receiving lenses satisfy the following conditions:

[0034] Transmitting lens: 28mm < TTL < 31mm, 25mm < EFL < 29mm, Distmax < 1.8%, emission angle -10.79°~10.79°; Receiving lens: TTL < 31mm, 15mm < EFL < 18mm, FOV -10.5°~10.5°, Distmax < 0.2%.

[0035] Furthermore, the maximum field-of-view laser divergence angle θ of the transmitting lens is <1.53 mrad, and the root mean square radius (RMS) of the receiving lens is <4 mm. Therefore, it can be concluded that the first, second, and third lenses can achieve laser collimation with high collimation accuracy, while the aberration correction of the receiving lens is excellent.

[0036] It should be noted that both the transmitting and receiving lenses mentioned above are used for light with a main wavelength of 905nm, and the exit pupil of the transmitting lens and the entrance pupil of the receiving lens are matched in position and size; at the same time, since the exit angle of the transmitting lens is slightly larger than the field of view of the receiving lens, the transmitting and receiving lenses are matched.

[0037] In one embodiment, in the transmitting lens, the first, second, and third lenses are all made of glass with an Abbe number Vd ≥ 23 to facilitate a thermal design within a temperature range of -40℃ to 125℃. In the receiving lens, the fourth, fifth, and seventh lenses are all made of glass, while the sixth lens is made of molded glass to facilitate a thermal design within a temperature range of -40℃ to 125℃. Furthermore, the object-side surface of the sixth lens is aspherical; using molded glass reduces the processing cost of aspherical lenses.

[0038] To facilitate understanding of the technical solution of this application, a specific embodiment is provided for illustration:

[0039] Example 1

[0040] For the transmitting lens: As shown in Table 1, the air gap between the laser and the first lens on the optical axis is 4.93 mm, the air gap between the first lens and the second lens on the optical axis is 4.13 mm, and the air gap between the second lens and the third lens on the optical axis is 12.96 mm.

[0041] Furthermore, the center thickness of the first lens is 2.7 mm, the radius of curvature of the surface facing the laser is -33.88 mm, and the radius of curvature of the surface facing away from the laser is -12.9 mm; the center thickness of the second lens is 4.13 mm, the radius of curvature of the surface facing the laser is 15.56 mm, and the radius of curvature of the surface facing away from the laser is 8 mm; the center thickness of the third lens is 3 mm, the radius of curvature of the surface facing the laser is -36 mm, and the radius of curvature of the surface facing away from the laser is -13.24 mm.

[0042] In this embodiment, the total optical length of the transmitting lens is TTL=30.72mm, the effective focal length is EFL=27.88mm, and the emission angle is -10.79°~10.79°.

[0043] Table 1 Component parameters of the transmitting lens

[0044]

[0045] For the receiving lens: As shown in Table 2, the air gap between the fourth and fifth lenses on the optical axis is 2.02 mm, the air gap between the fifth and sixth lenses on the optical axis is 3.06 mm, the air gap between the sixth and seventh lenses on the optical axis is 2.54 mm, and the air gap between the seventh lens and the image plane on the optical axis is 4.61 mm.

[0046] Furthermore, the fourth lens has a center thickness of 3.72 mm, an object-side radius of curvature of 13.64 mm, and an image-side radius of curvature of 79.49 mm; the fifth lens has a center thickness of 3 mm, an object-side radius of curvature of -22.72 mm, and an image-side radius of curvature of 20.59 mm; the sixth lens has a center thickness of 4 mm, an object-side radius of curvature of 30.25 mm, and an image-side radius of curvature of -14.63 mm; and the seventh lens has a center thickness of 4 mm, an object-side radius of curvature of 11.48 mm, and an image-side radius of curvature of 7.66 mm.

[0047] In this embodiment, the total optical length of the receiving lens is TTL=26.95mm, the effective focal length is EFL=16.12mm, the half field of view (HFOV) is 10.5°, and the GEO radius is <8.3μm.

[0048]

[0049] Table 2 Parameters of the Receiving Lens Components

[0050] It should be noted that, in Figure 1 and Figure 6 In this system, light rays travel from left to right. Therefore, along the optical axis, the left side of the lens is the laser side or object side, while the right side of the receiving lens is the image side. Referring to Tables 1 and 2, taking the first and fourth lenses as examples, the left side of the first lens is surface S1, and the right side is surface S2. The left side of the fourth lens is surface S7, and the right side is surface S8. The same applies to other lenses, which will not be elaborated upon here.

[0051] Figures 2 to 4 The above embodiments are dot plots of the transmitting lens at 20°C, -40°C, and 125°C, respectively. Figure 5 This is a schematic diagram of the field curvature and distortion of the transmitting lens in the above embodiment. Figures 7 to 9 The above embodiments are dot plots of the receiving lens at 20°C, -40°C, and 125°C, respectively. Figure 10 This is a schematic diagram of field curvature and distortion of the receiving lens in the above embodiment. Referring to the above figures, it can be seen that the transmitting and receiving lenses in the above embodiments have at least the following advantages:

[0052] 1. The transmitting lens has a good collimation effect on the beam. For VCSEL laser sources with a main wavelength of 905nm, the exit angle of the lens can reach -10° to 10°.

[0053] 2. The maximum GEO radius of the receiving lens is no more than 8.3μm, so it is suitable for SPAD (Single-Photon Avalanche Diode) detectors with pixels larger than 8μm, and the field of view of the receiving lens is -10.5°~10.5°, which can meet the long-distance detection requirements of lidar.

[0054] 3. The transmitting and receiving lenses have small apertures and fewer lenses, resulting in a compact structure that improves the internal space utilization of the lidar.

[0055] 4. The lenses in both the transmitting and receiving lenses are made of glass. The aspherical lenses are also made of molded glass, which is low in cost, easy to process, and can work normally in an environment of -40℃ to 125℃.

[0056] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A transmitting lens for lidar, characterized in that, It includes a first lens, a second lens, and a third lens arranged sequentially along the optical axis transmission direction. The first lens and the third lens are both meniscus positive lenses with their concave surfaces facing the laser side, and the second lens is a meniscus negative lens with its convex surface facing the laser side. The air gap between the laser and the first lens on the optical axis is 4.93 mm, the air gap between the first lens and the second lens on the optical axis is 4.13 mm, and the air gap between the second lens and the third lens on the optical axis is 12.96 mm. The first lens has a center thickness of 2.7 mm, a radius of curvature of -33.88 mm on the laser-facing side surface, and a radius of curvature of -12.9 mm on the laser-removing side surface; the second lens has a center thickness of 4.13 mm, a radius of curvature of 15.56 mm on the laser-facing side surface, and a radius of curvature of 8 mm on the laser-removing side surface; the third lens has a center thickness of 3 mm, a radius of curvature of -36 mm on the laser-facing side surface, and a radius of curvature of -13.24 mm on the laser-removing side surface.

2. The transmitting lens for lidar according to claim 1, characterized in that, The total optical length (TTL), effective focal length (EFL), emission angle, and maximum optical distortion (Distmax) of the transmitting lens satisfy the following conditions: 28mm < TTL < 31mm, 25mm < EFL < 29mm, emission angle is -10.79°~10.79°, Distmax < 1.8%.

3. A receiving lens for lidar, characterized in that, Matching the transmitting lens for lidar as described in claim 1 or 2, wherein the transmitting lens and the receiving lens are used for light with a main wavelength of 905 nm; The receiving lens includes a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis transmission direction. The fourth lens is a positive meniscus lens with its convex surface facing the object side, the fifth lens is a biconcave lens, the sixth lens is a biconvex lens, and the seventh lens is a negative meniscus lens with its convex surface facing the object side. The fourth lens has a center thickness of 3.72 mm, an object-side radius of curvature of 13.64 mm, and an image-side radius of curvature of 79.49 mm; the fifth lens has a center thickness of 3 mm, an object-side radius of curvature of -22.72 mm, and an image-side radius of curvature of 20.59 mm; the sixth lens has a center thickness of 4 mm, an object-side radius of curvature of 30.25 mm, and an image-side radius of curvature of -14.63 mm; the seventh lens has a center thickness of 4 mm, an object-side radius of curvature of 11.48 mm, and an image-side radius of curvature of 7.66 mm.

4. The receiving lens for lidar according to claim 3, characterized in that, The air gap between the fourth lens and the fifth lens on the optical axis is 2.02 mm, the air gap between the fifth lens and the sixth lens on the optical axis is 3.06 mm, the air gap between the sixth lens and the seventh lens on the optical axis is 2.54 mm, and the air gap between the seventh lens and the image plane on the optical axis is 4.61 mm.

5. The receiving lens for lidar according to claim 3, characterized in that, The total optical length (TTL), effective focal length (EFL), field of view (FOV), and maximum optical distortion (Distmax) of the receiving lens satisfy the following conditions: TTL < 31mm, 15mm < EFL < 18mm, FOV is -10.5° to 10.5°, Distmax < 0.2%.

6. A lidar, characterized in that, It includes the transmitting lens for lidar as described in claim 1 or 2 and the receiving lens for lidar as described in any one of claims 3-5.

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