Ultra-wide-angle laser radar transmitting lens and laser radar

Abstract

The application provides a kind of ultra-wide-angle laser radar transmitting lens, comprising first lens, second lens, third lens and fourth lens arranged in order from object side to image side;First lens is convex-concave lens with negative focal power, second lens is convex-concave lens with negative focal power, third lens is plano-convex lens with positive focal power, and fourth lens is biconvex lens with positive focal power.The refractive index Nd and dispersion coefficient Vd of first lens and second lens satisfy: Nd>1.88, Vd<36 respectively.The laser radar transmitting lens of the application has ultra-wide-angle, field of view FOV can reach 180°;Small size, lens length is small, only four spherical lenses are used, and the cost is low;Relative luminance RI is greater than 90%, and CRA (angle of chief ray at different angles hitting image plane) is less than 0.5°.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, and in particular to an ultra-wide-angle lidar transmitting lens and a lidar containing the transmitting lens. Background Technology

[0002] LiDAR, an active detection technology that uses laser beams to detect target distance and orientation by emitting laser beams and receiving their reflected signals, has been widely applied in fields such as autonomous driving, robot navigation, and 3D mapping due to its high detection accuracy and strong anti-interference capabilities. Compared to traditional mechanical rotating LiDAR, solid-state LiDAR eliminates rotating components, offering significant advantages: a compact spatial structure, a small near-field blind zone, and the ability to achieve a larger field of view, meeting the requirements for large field-of-view scanning.

[0003] The field of view of existing solid-state LiDAR lenses is insufficient to fully cover increasingly complex application scenarios, further increasing system complexity and cost. In addition, while some solid-state solutions improve the field of view and resolution, they often come at the cost of increased lens size and cost, making it difficult to meet the stringent requirements for integration and energy efficiency in automotive, mobile, and other portable devices.

[0004] Currently, the field of view of conventional radar transmitting lenses is generally between 120° and 150°, and the number of lenses used is 5 or more. Summary of the Invention

[0005] The present invention provides a low-cost ultra-wide-angle lidar transmitting lens and a lidar containing the transmitting lens, to solve at least one of the above-mentioned problems.

[0006] According to one aspect of the present invention, an ultra-wide-angle lidar transmitting lens is provided, comprising a first lens, a second lens, a third lens, and a fourth lens arranged sequentially from the object side to the image side; the first lens is a convex-concave lens with negative focal power, the second lens is a convex-concave lens with negative focal power, the third lens is a plano-convex lens with positive focal power, and the fourth lens is a biconvex lens with positive focal power; the refractive index Nd and dispersion coefficient Vd of the first lens and the second lens respectively satisfy: Nd>1.88, Vd<36.

[0007] The laser radar transmitting lens of this invention has an ultra-wide angle, with a field of view (FOV) of up to 180°; it is small in size, with a short lens length, using only four spherical lenses, resulting in low cost; the relative illumination (RI) is greater than 90%, and the CRA (angle of the principal ray hitting the image plane at different angles) is less than 0.5°.

[0008] In some embodiments, the optical power of the first lens of the present invention 1 satisfies: -0.15 < 1 < -0.08; Optical power of the second lens 2 satisfies: -0.27 < 2 < -0.15. Choosing the optical power of the first and second lenses within this range allows for better focusing of a wide field of view beam.

[0009] In some embodiments, the optical power of the first lens of the present invention 1 = -0.12; Optical power of the second lens 2 = -0.26. Therefore, the relative illumination of the lens can approach 100%.

[0010] In some embodiments, an aperture stop is provided between the second lens and the third lens of the present invention. This allows for beam control, which helps to improve the system signal-to-noise ratio.

[0011] In some embodiments, the refractive index Nd and dispersion coefficient Vd of the third lens of the present invention satisfy the following conditions: Nd>1.89, Vd<36.

[0012] In some embodiments, the refractive index Nd and dispersion coefficient Vd of the fourth lens of the present invention satisfy the following conditions: Nd>1.84, Vd<25.5.

[0013] In some embodiments, the first lens, second lens, third lens, and fourth lens of the present invention are all made of glass. Therefore, the present emitting lens can meet the performance requirements in environments with temperatures ranging from -40°C to +105°C.

[0014] According to another aspect of the present invention, a lidar is also provided, comprising the aforementioned ultra-wide-angle lidar transmitting lens. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of an ultra-wide-angle lidar transmitting lens according to one embodiment of the present invention; Figure 2 This is a schematic diagram of the structure and optical path of an ultra-wide-angle lidar transmitting lens according to one embodiment of the present invention; Figure 3 for Figure 2 The diagram shows a dot matrix of the ultra-wide-angle lidar transmitting lens. Figure 4 for Figure 2 The MTF curve of the ultra-wide-angle lidar transmitting lens is shown below; Figure 5 for Figure 2 The diagram shows the relative illumination curve of the ultra-wide-angle lidar transmitting lens; Figure 6 This is a schematic diagram of the structure and optical path of an ultra-wide-angle lidar transmitting lens according to another embodiment of the present invention; Figure 7 for Figure 6The diagram shows a dot matrix of the ultra-wide-angle lidar transmitting lens. Figure 8 for Figure 6 The MTF curve of the ultra-wide-angle lidar transmitting lens is shown below; Figure 9 for Figure 6 The diagram shows the relative illumination curve of the ultra-wide-angle lidar transmitting lens; Figure 10 This is a schematic diagram of the structure of an ultra-wide-angle lidar transmitting lens according to another embodiment of the present invention; Figure 11 for Figure 10 The diagram shows a dot matrix of the ultra-wide-angle lidar transmitting lens. Figure 12 for Figure 10 The MTF curve of the ultra-wide-angle lidar transmitting lens is shown below; Figure 13 for Figure 10 The diagram shows the relative illumination curve of the ultra-wide-angle lidar transmitting lens. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0018] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising" or "including" include not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0019] The present invention will now be described in further detail with reference to the accompanying drawings.

[0020] Figure 1The structure of an ultra-wide-angle lidar transmitting lens according to one embodiment of the present invention is schematically shown.

[0021] refer to Figure 1 As shown, the ultra-wide-angle lidar transmitting lens includes a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4 arranged sequentially from the object side to the imaging surface 6. All four lenses are made of glass and can meet the performance requirements of an environment with an ambient temperature of -40℃ to +105℃.

[0022] The first lens 1 is a convex-concave lens with negative focal power, with the convex surface facing the object surface.

[0023] The second lens 2 is a convex-concave lens with negative focal power, with the convex surface facing the object surface.

[0024] The third lens 3 is a plano-convex lens with positive focal length, and its plane faces the object plane.

[0025] The fourth lens 4 is a biconvex lens with positive focal length.

[0026] An aperture stop 5 can also be set between the second lens 2 and the third lens 3.

[0027] The refractive index Nd and dispersion coefficient (Abbe number Vd) of the first lens 1 and the second lens 2 satisfy the following conditions: Nd>1.88 and Vd<36, respectively.

[0028] Optical power of the first lens 1 1 satisfies: -0.15 < 1 < -0.08.

[0029] The optical power of the second lens 2 2 satisfies: -0.27 < 2 < -0.15.

[0030] The ultra-wide-angle lidar transmitting lens has a maximum field of view (FOV) of 180°, a CRA (angle of principal rays hitting the image plane at different angles) of less than 0.5°, an operating wavelength of 940nm ±20nm, a relative illumination of more than 90%, and can maintain clear imaging without defocusing even in environments ranging from -40℃ to +105℃.

[0031] Figure 2 schematically shown Figure 1 The diagram shows the structure of the ultra-wide-angle lidar transmitting lens and the deflection direction of light through each component.

[0032] refer to Figure 2 As shown in the diagram, the concave and convex shapes of the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 in this embodiment, as well as the deflection direction of light after passing through each lens, can be seen from the optical path diagram.

[0033] Table 1 shows the lens-related parameters in this embodiment:

[0034] In Table 1, S1 and S2 correspond to the object-side and image-side surfaces of the first lens 1, respectively; S3 and S4 correspond to the object-side and image-side surfaces of the second lens 2, respectively; S6 and S7 correspond to the object-side and image-side surfaces of the third lens 3, respectively; and S8 and S9 correspond to the object-side and image-side surfaces of the fourth lens 4, respectively. The thickness corresponds to the distance from this surface to the next surface in the direction of light propagation.

[0035] The technical specifications achieved in this embodiment are as follows: 1. Focal length f0: 1.15mm; 2. Aperture number F#: 1.93; 3. Operating wavelength: 940nm±20nm; 4. Field of view 2ω: 180°; 5. Relative illumination: The relative illumination across the entire field of view is greater than 90%; 6. Optical CRA: less than 0.5°; 7. Overall optical length: 21.95mm; 8. Optical power of the first lens 1 1 = -0.09; Optical power of the second lens 2 2 = -0.24.

[0036] Figure 3 schematically shown Figure 2 The image shows a dot matrix of the ultra-wide-angle lidar transmitting lens.

[0037] refer to Figure 3 As shown in the dot plot, the RMS (root mean square) blur spot diameter corresponding to the field of view is less than 45 μm across the entire field of view, and the RMS values ​​of the center field of view (0°) and the edge field of view (±90°) are less than 10 μm. This transmitting lens has excellent focusing capability across the entire field of view.

[0038] Figure 4 schematically shown Figure 2 The MTF curve of the ultra-wide-angle lidar transmitting lens is shown.

[0039] refer to Figure 4 As shown in the MTF curve, the modulation of different spatial frequencies under various fields of view of the transmitting lens can be seen. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. It can be seen that the MTF curve of this embodiment decreases smoothly and evenly from the center to the edge of the field of view, and has good imaging quality under different fields of view.

[0040] Figure 5 schematically shown Figure 2 The relative illumination curve of the ultra-wide-angle lidar transmitting lens is shown.

[0041] refer to Figure 5 As shown in the relative illuminance curve, in this embodiment, the relative illuminance is greater than 90% within a 180° field of view. This indicator indicates that the energy attenuation at the edge of the field of view is effectively suppressed, so that the emitted beam exhibits a uniform irradiance distribution throughout the entire projection area.

[0042] Figure 6 The diagram schematically illustrates the structure of an ultra-wide-angle lidar transmitting lens according to another embodiment of the present invention, and the deflection direction of light through each component.

[0043] Table 2 shows the lens-related parameters in this embodiment:

[0044] In Table 2, S1 and S2 correspond to the object-side and image-side surfaces of the first lens 1, respectively; S3 and S4 correspond to the object-side and image-side surfaces of the second lens 2, respectively; S6 and S7 correspond to the object-side and image-side surfaces of the third lens 3, respectively; and S8 and S9 correspond to the object-side and image-side surfaces of the fourth lens 4, respectively. The thickness corresponds to the distance from this surface to the next surface in the direction of light propagation.

[0045] The technical specifications implemented in this embodiment are as follows: 1. Focal length: f0 = 1.06mm; 2. Aperture number F#=1.90; 3. Operating wavelength: 940nm±20nm; 4. Field of view 2ω: 180°; 5. Relative illumination: The relative illumination across the entire field of view is greater than 90%; 6. Optical CRA: less than 0.5°; 7. Overall optical length: 22mm.

[0046] 8. Optical power of the first lens 1 1 = -0.14; Optical power of the second lens 2 2 = -0.16.

[0047] refer to Figure 6 As shown in the diagram, the concave and convex shapes of the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4, as well as the deflection direction of the light rays after passing through each lens, can be seen from the optical path diagram.

[0048] Figure 7 schematically shown Figure 6The diagram shows a dot matrix of ultra-wide-angle lidar transmitting lenses.

[0049] refer to Figure 7 As shown in the dot plot, it can be seen that the RMS (root mean square) blur diameter of each field of view is less than 45 μm across the entire field of view, and the RMS values ​​of the center field of view (0°) and the edge field of view (±90°) are less than 10 μm. This transmitting lens has excellent focusing capability across the entire field of view.

[0050] Figure 8 schematically shown Figure 6 The MTF curve of the ultra-wide-angle lidar transmitting lens is shown.

[0051] refer to Figure 8 As shown in the MTF curve, the modulation of different spatial frequencies under various fields of view of the transmitting lens can be seen. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. It can be seen that the MTF curve of this embodiment decreases smoothly and evenly from the center to the edge of the field of view, and has good imaging quality under different fields of view.

[0052] Figure 9 schematically shown Figure 6 The relative illumination curve of the ultra-wide-angle lidar transmitting lens is shown.

[0053] refer to Figure 9 As shown in the relative illuminance curve, in this embodiment, the relative illuminance is greater than 90% within a 180° field of view. This indicator indicates that the energy attenuation at the edge of the field of view is effectively suppressed, so that the emitted beam exhibits a uniform irradiance distribution throughout the entire projection area.

[0054] Figure 10 The diagram schematically illustrates the structure of an ultra-wide-angle lidar transmitting lens according to another embodiment of the present invention, and the deflection direction of light through each component.

[0055] Table 3 shows the lens-related parameters in this embodiment.

[0056] In Table 3, S1 and S2 correspond to the object-side and image-side surfaces of the first lens 1, respectively; S3 and S4 correspond to the object-side and image-side surfaces of the second lens 2, respectively; S6 and S7 correspond to the object-side and image-side surfaces of the third lens 3, respectively; and S8 and S9 correspond to the object-side and image-side surfaces of the fourth lens 4, respectively. The thickness corresponds to the distance from this surface to the next surface in the direction of light propagation.

[0057] The technical specifications implemented in this embodiment are as follows: 1. Lens focal length: f0 = 1.12mm; 2. Aperture F#: 2.08; 3. Operating wavelength: 940nm±20nm; 4. Field of view 2ω: 180°; 5. Relative illumination: The relative illumination across the entire field of view is greater than 90%; 6. Optical CRA: less than 0.5°; 7. Overall optical length: 21.5mm; 8. Optical power of the first lens 1 1 = -0.12; Optical power of the second lens 2 2 = -0.26.

[0058] refer to Figure 10 As shown in the diagram, the concave and convex shapes of the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4, as well as the deflection direction of the light rays after passing through each lens, can be seen from the optical path diagram.

[0059] Figure 11 schematically shown Figure 10 The diagram shows a dot matrix of ultra-wide-angle lidar transmitting lenses.

[0060] refer to Figure 11 As shown in the dot plot, the RMS (root mean square) blur diameter of the corresponding field of view is less than 45 μm across the entire field of view, indicating that the transmitting lens has excellent focusing capability across the entire field of view.

[0061] Figure 12 schematically shown Figure 10 The MTF curve of the ultra-wide-angle lidar transmitting lens is shown.

[0062] refer to Figure 12 As shown in the MTF curve, the modulation of different spatial frequencies under various fields of view of the transmitting lens can be seen. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. It can be seen that the MTF curve of this embodiment decreases smoothly and evenly from the center to the edge of the field of view, and has good imaging quality under different fields of view.

[0063] Figure 13 schematically shown Figure 10 The relative illumination curve of the ultra-wide-angle lidar transmitting lens is shown.

[0064] refer to Figure 13 As shown in the relative illuminance curve, in this embodiment, the relative illuminance is greater than 90% (close to 100%) within a 180° field of view. This indicator indicates that the energy attenuation at the edge of the field of view is effectively suppressed, so that the emitted beam exhibits a uniform irradiance distribution throughout the entire projection area.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing examples, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various examples of this application.

Claims

1. An ultra-wide-angle lidar transmitting lens, characterized in that, It includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially from the object side to the image side; The first lens is a convex-concave lens with negative power, the second lens is a convex-concave lens with negative power, the third lens is a plano-convex lens with positive power, and the fourth lens is a biconvex lens with positive power. The refractive index Nd and dispersion coefficient Vd of the first lens and the second lens satisfy the following conditions: Nd>1.88, Vd<36.

2. The ultra-wide-angle lidar transmitting lens according to claim 1, characterized in that, The optical power of the first lens 1 satisfies: -0.15 < 1 < -0.08; The optical power of the second lens 2 satisfies: -0.27< 2 < -0.

15.

3. The ultra-wide-angle lidar transmitting lens according to claim 2, characterized in that, The optical power of the first lens 1 = -0.12; Optical power of the second lens 2 = -0.

26.

4. The ultra-wide-angle lidar transmitting lens according to claim 2, characterized in that, An aperture stop is provided between the second lens and the third lens.

5. The ultra-wide-angle lidar transmitting lens according to any one of claims 1-4, characterized in that, The refractive index Nd and dispersion coefficient Vd of the third lens satisfy the following conditions: Nd>1.89, Vd<36.

6. The ultra-wide-angle lidar transmitting lens according to any one of claims 1-4, characterized in that, The refractive index Nd and dispersion coefficient Vd of the fourth lens satisfy the following conditions: Nd>1.84, Vd<25.

5.

7. The ultra-wide-angle lidar transmitting lens according to any one of claims 1-4, characterized in that, The first lens, the second lens, the third lens, and the fourth lens are all made of glass.

8. A lidar, characterized in that, Includes the ultra-wide-angle lidar transmitting lens as described in any one of claims 1-7.

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