Solid-state laser radar RX lens

Abstract

The invention provides a solid-state laser radar RX lens, and belongs to the technical field of optical imaging, and the solid-state laser radar RX lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged in the optical axis direction. The object side surfaces and the image side surfaces of the second lens, the third lens and the sixth lens are rotationally symmetrical aspheric surfaces; the focal powers of the six groups of lenses are sequentially negative focal power, positive focal power, negative focal power, positive focal power, positive focal power and positive focal power in the arrangement direction, or the focal powers of the six groups of lenses are sequentially negative focal power, positive focal power, positive focal power, positive focal power, positive focal power and positive focal power in the arrangement direction; in addition, the lens also satisfies set optical parameter conditions. The solid-state laser radar RX lens provided by the invention can simultaneously meet the requirements of low cost, easy assembly, large field of view and high imaging quality.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and particularly to a solid-state lidar RX lens. Background Art

[0002] With the evolution of autonomous driving technology towards higher-order intelligence, as a core perception device, the performance and reliability requirements of solid-state lidar have been significantly improved. For example, current high-order autonomous driving systems have high requirements for perception accuracy, and need to achieve ultra-wide field of view and high resolution in complex scenarios. For example, above 180° horizontally and above 40LP / mm, a collaborative optimization with an MTF (Modulation Transfer Function) value greater than 0.3 is required. At the same time, cost controllability needs to be considered to adapt to large-scale deployment.

[0003] In the prior art, for example, patent document CN119024524A discloses a lidar lens, which adopts a combined structure of two groups of free-form lenses and three groups of spherical lenses. Although the MTF value at a specific spatial frequency is greater than 0.5, its field of view angle is difficult to meet the wide-area coverage requirement, and the high manufacturing cost and complex assembly and adjustment process of the free-form lenses further limit the mass production feasibility.

[0004] Therefore, there is an urgent need for a solid-state lidar optical system that takes into account large field of view, high resolution, low cost and easy assembly to break through the current technical bottleneck and meet the urgent needs of high-performance and high-reliability sensors in the fields of autonomous driving and industrial perception. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide a solid-state lidar RX lens, aiming to meet the requirements of low cost, easy assembly, large field of view and high imaging quality.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A solid-state lidar RX lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in sequence along the optical axis direction. The object side and the image side of the second lens, the third lens, and the sixth lens are both rotationally symmetric aspheres; the optical powers of the six groups of lenses are negative optical power, positive optical power, negative optical power, positive optical power, positive optical power, and positive optical power in sequence along the arrangement direction, or the optical powers of the six groups of lenses are negative optical power, positive optical power, positive optical power, positive optical power, positive optical power, and positive optical power in sequence along the arrangement direction;

[0007] The solid-state lidar RX lens satisfies the following optical parameter conditions:

[0008] 0.08 < |f1 / f2| < 0.25;

[0009] 1.50 < |f2 / f3| < 7.90;

[0010] 0.50 < |f3 / f4| < 1.99;

[0011] 0.2 < |f4 / f5| < 2.22;

[0012] 0.30 < |f5 / f6| < 0.95;

[0013] 150° < FOV < 170°;

[0014] Wherein, f1, f2, f3, f4, f5, and f6 are the effective focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens respectively, in millimeters, and FOV is the field of view angle of the RX lens of the solid-state lidar.

[0015] In addition, the RX lens of the solid-state lidar according to the above of the present invention may further have the following additional technical features:

[0016] Further, the RX lens of the solid-state lidar further includes an aperture stop, and the aperture stop is located between the second lens and the third lens.

[0017] Further, the RX lens of the solid-state lidar satisfies the following optical parameter conditions:

[0018] 45 < TTL < 50;

[0019] Wherein, TTL is the total optical length of the RX lens of the solid-state lidar, in millimeters.

[0020] Further, the RX lens of the solid-state lidar satisfies the following optical parameter conditions:

[0021] 4.8 ≤ BFL ≤ 5.5;

[0022] Wherein, BFL is the distance on the optical axis from the image side of the sixth lens to the image plane of the RX lens of the solid-state lidar, in millimeters.

[0023] Further, the RX lens of the solid-state lidar satisfies the following optical parameter conditions:

[0024] 1.0 < IH / f < 1.2;

[0025] Wherein, IH is the actual semi-image height of the RX lens of the solid-state lidar, and f is the total effective focal length of the RX lens of the solid-state lidar, in millimeters.

[0026] Further, the RX lens of the solid-state lidar satisfies the following optical parameter conditions:

[0027] 12 < TTL / IH < 17;

[0028] Wherein, IH is the actual semi-image height of the RX lens of the solid-state lidar, with the unit of millimeter.

[0029] Further, the RX lens of the solid-state lidar satisfies the following optical parameter conditions:

[0030] 0.5° < CRA < 2.0°;

[0031] Wherein, CRA is the maximum principal ray incident angle on the image plane of the RX lens of the solid-state lidar.

[0032] Further, the RX lens of the solid-state lidar satisfies the following optical parameter conditions:

[0033] 2.05 < DM1 / DM2 < 2.75;

[0034] 0.93 < DM2 / DM3 < 1.75;

[0035] 0.50 < DM3 / DM4 < 1.05;

[0036] 0.70 < DM4 / DM5 < 1.15;

[0037] 0.92 < DM5 / DM6 < 1.15;

[0038] Wherein, DM1, DM2, DM3, DM4, DM5, and DM6 are the effective apertures of the object sides of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens respectively, with the unit of millimeter.

[0039] Further, the RX lens of the solid-state lidar satisfies the following optical parameter conditions:

[0040] 1.15 ≤ Fno ≤ 1.30;

[0041] Wherein, Fno is the aperture size of the RX lens of the solid-state lidar.

[0042] Further, the working wavelength band of the RX lens of the solid-state lidar is 885 nm to 925 nm, and the main wavelength is 905 nm.

[0043] The beneficial effects of the present invention at least include: 1. Through the combination design of a six-lens combination structure (alternating positive and negative optical powers of the first to sixth lenses) and multiple aspherical lenses, while achieving a large field of view angle, the field curvature and distortion caused by the large field of view are effectively corrected. At the same time, in combination with a large aperture design, the optical modulation ability of the edge field of view can be significantly improved; 2. By adopting the scheme of using only the second, third, and sixth lenses with aspherical designs (the rest are spherical), compared with the fully free-form surface design, the lens assembly and processing yield can be improved, and the manufacturing cost can be reduced; 3. Through the constraint of the ratio of the total optical length TTL / IH and the control of the back focal length BFL, an IH / f ratio greater than 1.0 is achieved within a compact size, enabling the system to have both miniaturization and high imaging surface illuminance uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 FIG. is a schematic structural diagram of the RX lens of the solid-state lidar in Embodiment 1 of the present invention;

[0045] Figure 2 FIG. is the SPOT SIZE diagram of the RX lens of the solid-state lidar in Embodiment 1 of the present invention;

[0046] Figure 3 FIG. is the field curvature diagram and the distortion diagram within a field of view angle of 150 degrees of the RX lens of the solid-state lidar in Embodiment 1 of the present invention;

[0047] Figure 4 FIG. is a schematic structural diagram of the RX lens of the solid-state lidar in Embodiment 2 of the present invention;

[0048] Figure 5 FIG. is the SPOT SIZE diagram of the RX lens of the solid-state lidar in Embodiment 2 of the present invention;

[0049] Figure 6 FIG. is the field curvature diagram and the distortion diagram within a field of view angle of 150 degrees of the RX lens of the solid-state lidar in Embodiment 2 of the present invention;

[0050] Figure 7 FIG. is a schematic structural diagram of the RX lens of the solid-state lidar in Embodiment 3 of the present invention;

[0051] Figure 8 FIG. is the SPOT SIZE diagram of the RX lens of the solid-state lidar in Embodiment 3 of the present invention;

[0052] Figure 9 FIG. is the field curvature diagram and the distortion diagram within a field of view angle of 150 degrees of the RX lens of the solid-state lidar in Embodiment 3 of the present invention;

[0053] The following specific embodiments will further illustrate the present invention in conjunction with the above drawings. SPECIFIC EMBODIMENTS

[0054] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant accompanying drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0055] It should be noted that in this specification, the expressions such as first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teachings of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0056] In the accompanying drawings of the present application, for the convenience of illustration, the thickness, size and shape of the lens have been slightly exaggerated. Specifically, the spherical or aspherical shapes shown in the drawings are shown by way of example. That is, the spherical or aspherical shapes are not limited to the spherical or aspherical shapes shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0057] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object to be photographed is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

[0058] It should also be understood that the terms "comprising", "including", "having", "containing" and / or "including" as used herein, when used in this specification, mean the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when an expression such as "at least one of..." appears after the list of listed features, it modifies the entire list of listed features, rather than modifying the individual elements in the list. In addition, when describing the embodiments of the present application, the use of "may" means "one or more embodiments of the present application". And the term "exemplarily" is intended to refer to an example or illustration.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0060] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The following will describe the present application in detail with reference to the drawings and in combination with the embodiments.

[0061] The features, principles, and other aspects of the present application will be described in detail below.

[0062] Please refer to Figure 1 、 Figure 3 、 Figure 5 、 Figure 7 、 Figure 9 For a solid-state lidar RX lens provided by the present invention, it includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6 arranged in sequence along the optical axis direction. Among them, the object side and the image side of the second lens L2, the third lens L3, and the sixth lens L6 are both rotationally symmetric aspheres. The optical powers of the six groups of lenses are, in sequence along the arrangement direction, negative optical power, positive optical power, negative optical power, positive optical power, positive optical power, positive optical power; or the optical powers of the six groups of lenses are, in sequence along the arrangement direction, negative optical power, positive optical power, positive optical power, positive optical power, positive optical power, positive optical power.

[0063] In addition, the solid-state lidar RX lens also satisfies the following optical parameter conditions:

[0064] 0.08 < |f1 / f2| < 0.25;

[0065] 1.50 < |f2 / f3| < 7.90;

[0066] 0.50 < |f3 / f4| < 1.99;

[0067] 0.2 < |f4 / f5| < 2.22;

[0068] 0.30 < |f5 / f6| < 0.95;

[0069] 150° < FOV < 170°;

[0070] Wherein, f1, f2, f3, f4, f5, and f6 are the effective focal lengths of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 respectively, with the unit of millimeter, and FOV is the field of view angle of the solid-state lidar RX lens.

[0071] When the solid-state lidar RX lens provided by the present application satisfies the above conditional expressions, the solid-state lidar RX lens has strong overall compactness and miniaturization characteristics, and at the same time can ensure a wide working distance.

[0072] To achieve a balance between high imaging quality and a compact structure, preferably, the solid-state lidar RX lens provided in this application further satisfies the optical parameter conditions shown in Table 1:

[0073] Table 1

[0074] <![CDATA[n d1 > <![CDATA[n d2 > <![CDATA[n d3 > <![CDATA[n d4 > <![CDATA[n d5 > <![CDATA[n d6 > 1.6±10％ 1.8±10％ 1.8±10％ 1.8±10％ 1.65±10％ 1.6±10％ <![CDATA[v d1 > <![CDATA[v d2 > <![CDATA[v d3 > <![CDATA[v d4 > <![CDATA[v d5 > <![CDATA[V d6 > 49±40％ 41.0±10％ 41.1±10％ 41.0±10％ 49±40％ 40±40％

[0075] Among them, n d1 、n d2 、n d3 、n d4 、n d5 、n d6 are the refractive indices of the first lens L1 to the sixth lens L6 in sequence, and v d1 、v d2 、v d3 、v d4 、v d5 、v d6 are the Abbe numbers of the first lens L1 to the sixth lens L6 in sequence.

[0076] In some alternative embodiments, the solid-state lidar RX lens further includes an aperture stop STO, and the aperture stop STO is located between the second lens L2 and the third lens L3.

[0077] In some alternative embodiments, the solid-state lidar RX lens further satisfies the following optical parameter conditions:

[0078] 45 < TTL < 50;

[0079] Among them, TTL is the total optical length of the solid-state lidar RX lens, and the unit is millimeter.

[0080] When the solid-state lidar RX lens provided in this application satisfies the above conditional formula, the total length of the lens is controlled within 50 mm, and various application scenarios with space limitations can be satisfied.

[0081] In some alternative embodiments, the solid-state lidar RX lens further satisfies the following optical parameter conditions:

[0082] 4.8 ≤ BFL ≤ 5.5;

[0083] Among them, BFL is the distance from the image side of the sixth lens L6 to the image plane of the solid-state lidar RX lens on the optical axis, and the unit is millimeter.

[0084] When the solid-state lidar RX lens provided in this application satisfies the above conditional formula, the imaging quality, mechanical compatibility, and robustness to environmental changes of the optical system can be improved.

[0085] In some alternative embodiments, the solid-state lidar RX lens further satisfies the following optical parameter conditions:

[0086] 1.0 < IH / f < 1.2;

[0087] Wherein, IH is the actual semi-image height of the RX lens of the solid-state lidar, and f is the total effective focal length of the RX lens of the solid-state lidar, with the unit of millimeter.

[0088] When the RX lens of the solid-state lidar provided by this application satisfies the above conditional formula, the field of view and volume can be balanced, and the lens has a large field of view angle while achieving miniaturization.

[0089] In some alternative embodiments, the RX lens of the solid-state lidar further satisfies the following optical parameter conditions:

[0090] 12 < TTL / IH < 17;

[0091] Wherein, IH is the actual semi-image height of the RX lens of the solid-state lidar, with the unit of millimeter.

[0092] When the RX lens of the solid-state lidar provided by this application satisfies the above conditional formula, the system compactness and the field of view coverage size can be balanced, ensuring a large field of view while achieving miniaturization of the lens.

[0093] In some alternative embodiments, the RX lens of the solid-state lidar further satisfies the following optical parameter conditions:

[0094] 0.5° < CRA < 2.0°;

[0095] Wherein, CRA is the maximum principal ray incident angle on the image plane of the RX lens of the solid-state lidar.

[0096] When the RX lens of the solid-state lidar provided by this application satisfies the above conditional formula, the lens has smaller astigmatism, field curvature, and distortion.

[0097] In some alternative embodiments, the RX lens of the solid-state lidar further satisfies the following optical parameter conditions:

[0098] 2.05 < DM1 / DM2 < 2.75;

[0099] 0.93 < DM2 / DM3 < 1.75;

[0100] 0.50 < DM3 / DM4 < 1.05;

[0101] 0.70 < DM4 / DM5 < 1.15;

[0102] 0.92 < DM5 / DM6 < 1.15;

[0103] Wherein, DM1, DM2, DM3, DM4, DM5, and DM6 are the effective apertures of the object sides of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 respectively, with the unit of millimeter.

[0104] When the RX lens of the solid-state lidar provided in this application satisfies the above conditional formula, a larger light flux, better vignetting control, and aberration correction can be achieved.

[0105] In some optional embodiments, the RX lens of the solid-state lidar further satisfies the following optical parameter conditions:

[0106] 1.15 ≤ Fno ≤ 1.30;

[0107] Wherein, Fno is the aperture size of the RX lens of the solid-state lidar.

[0108] When the RX lens of the solid-state lidar provided in this application satisfies the above conditional formula, a larger aperture can achieve the detection of the surrounding environment at close range.

[0109] In some optional embodiments, the working wavelength band of the RX lens of the solid-state lidar is 885nm - 925nm, and the main wavelength is 905nm.

[0110] Next, in conjunction with Figures 1 to 9 Some specific but non-limiting examples of the embodiments of this application will be described in more detail. It should be noted that the following embodiments mainly analyze the light rays with a reference wavelength of 905nm.

[0111] Embodiment 1:

[0112] As Figure 1 shown, a RX lens of a solid-state lidar provided by the present invention. In this embodiment, the RX lens of the solid-state lidar includes a first lens L1 with a negative optical power, a second lens L2 with a positive optical power, an aperture stop STO, a third lens L3 with a negative optical power, a fourth lens L4 with a positive optical power, a fifth lens L5 with a positive optical power, a sixth lens L6 with a positive optical power, and a filter IR arranged in sequence along the optical axis direction. The lens forms an image on the image plane IMG.

[0113] In terms of shape and structure, the first lens L1 is a convex-concave spherical lens, the second lens L2 is a convex-concave aspherical lens, the third lens L3 is a convex-concave aspherical lens, the fourth lens L4 is a biconvex spherical lens, the fifth lens L5 is a biconvex spherical lens, and the sixth lens L6 is a convex-concave aspherical lens; wherein, the object sides and image sides of the second lens L2, the third lens L3, and the sixth lens L6 are all rotationally symmetric aspheres.

[0114] In terms of physical dimensions, the physical semi-apertures of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are 6.15 mm, 2.66 mm, 2.44 mm, 4.62 mm, 5.90 mm, and 5.29 mm in sequence.

[0115] In terms of optical parameters, the total effective focal length f of the lens is 3.06 mm, the entrance pupil diameter is 2.45 mm, the ratio of the true semi-image height IH corresponding to the maximum field of view angle to the total effective focal length f of the lens is 1.04, and the ratio of the total optical length TTL to the true semi-image height IH corresponding to the maximum field of view angle is 16.25.

[0116] Specifically, the specific parameters of each lens in the solid-state lidar RX lens in this embodiment and the substrate materials used are shown in Table 2:

[0117] Table 2

[0118]

[0119] In this embodiment, the aspheres of the aspherical lenses (the second lens L2, the third lens L3, and the sixth lens L6) satisfy the following aspherical formula:

[0120]

[0121] Where Z is the sagitta, c is the reciprocal of the radius of curvature R, y is the radial coordinate, k is the conic quadratic coefficient, and A2, A3, A4, A5, A6, A7, A8 are the aspherical high-order coefficients. The specific aspherical parameters of the second lens L2, the third lens L3, and the sixth lens L6 are shown in Table 3:

[0122] Table 3

[0123]

[0124]

[0125] Among them, the surface numbers L2S1, L3S1, and L6S1 respectively represent the object sides of the second lens L2, the third lens L3, and the sixth lens L6, and the surface numbers L2S2, L3S2, and L6S2 respectively represent the image sides of the second lens L2, the third lens L3, and the sixth lens L6.

[0126] It can be understood that the aspheres of each aspherical lens in the solid-state lidar RX lens in this embodiment can use the aspheres constrained by the above aspherical formula, or can use the aspheres constrained by other aspherical formulas, which is not limited in this application.

[0127] Figure 2Describes the SPOT SIZE diagram (spot size diagram) of the RX lens of a solid-state lidar designed in the lens combination mode of Embodiment 1. The SPOT SIZE diagram is mainly used to evaluate the distribution size and shape of the spot on the image plane, and reflects the focusing ability of the system on the point light source or the influence of aberrations (such as spherical aberration, coma, astigmatism, etc.). In the SPOT SIZE diagram, RMSRadius represents the spot result after root mean square processing (unit: micron), and this result is closer to the spot value in actual production. GEO Radius represents the distance between the two farthest points of the spot (unit: micron). Specifically, it can be seen from the figure that GEO Radius is less than 3*(RMS Radius), indicating that the lens design result is relatively good. Moreover, in the process of the field of view from the center to the edge in the infrared band, the spot size shows a gradually increasing trend. When the half field of view angle is 75 degrees, RMS Radius is less than 8um. For an image sensor chip with a pixel size less than 10 microns, its large field of view resolution can be guaranteed. When the half field of view angle is 0 degrees, RMS Radius is less than 2um. For an image sensor chip with a pixel size less than 5um, its paraxial resolution can be guaranteed.

[0128] Figure 3 From left to right, it successively describes the field curvature diagram and distortion diagram of the RX lens of a solid-state lidar designed in the lens combination mode of Embodiment 1.

[0129] Specifically, in the field curvature diagram, the abscissa represents the offset (unit: mm), and the ordinate represents the field of view angle (unit: degree). Among them, the S curve represents the sagittal field curvature at a wavelength of 905nm, and the T curve represents the meridional field curvature at a wavelength of 905nm. It can be known from the field curvature diagram that the field curvature of the RX lens of the solid-state lidar in this embodiment is within 0.05mm, indicating that the field curvature and astigmatism of each field of view have been well corrected, so that clear imaging can be obtained at both the center and the edge of the field of view.

[0130] In the distortion diagram, the abscissa represents the distortion value (unit: %), and the ordinate represents the field of view angle (unit: degree). It can be known from the distortion diagram that the optical distortion is less than 75% within a field of view angle of 150 degrees, which matches the distortion of the transmitting end and can eliminate systematic errors to a certain extent.

[0131] To sum up, the optical lens in this embodiment adopts three spherical lenses and three aspherical lenses. By matching the optical powers with negative, positive, and negative values and effectively distributing the optical power through the aspherical lenses, the imaging quality of the lens is improved. The overall structure is compact. At the same time, the overall optical length TTL is less than 50mm, which can achieve the purpose of miniaturization. In addition, a large aperture configuration can be realized to meet clear imaging in low light conditions.

[0132] Embodiment 2:

[0133] As shown Figure 4 in the figure, a solid-state lidar RX lens provided by the present invention is shown. In this embodiment, the solid-state lidar RX lens includes a first lens L1 with a negative optical power, a second lens L2 with a positive optical power, an aperture stop STO, a third lens L3 with a positive optical power, a fourth lens L4 with a positive optical power, a fifth lens L5 with a positive optical power, a filter IR, and a sixth lens L6 with a positive optical power, which are arranged in sequence along the optical axis direction, and the imaging of the lens is on the image plane IMG.

[0134] In terms of the shape and structure, the first lens L1 is a convex-concave spherical lens, the second lens L2 is a convex-concave aspherical lens, the third lens L3 is a convex-concave aspherical lens, the fourth lens L4 is a convex-concave spherical lens, the fifth lens L5 is a biconvex spherical lens, and the sixth lens L6 is a convex-concave aspherical lens; among them, the object side and the image side of the second lens L2, the third lens L3, and the sixth lens L6 are both rotationally symmetric aspheres.

[0135] In terms of the physical dimensions, the physical semi-apertures of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are 6.85 mm, 2.99 mm, 2.89 mm, 4.44 mm, 5.82 mm, and 5.71 mm in sequence.

[0136] In terms of the optical parameters, the total effective focal length f of the lens is 2.995 mm, the entrance pupil diameter is 2.49 mm, the ratio of the true semi-image height IH corresponding to the maximum field of view angle to the total effective focal length f of the lens is 1.06, and the ratio of the optical total length TTL to the true semi-image height IH corresponding to the maximum field of view angle is 12.5.

[0137] Specifically, the specific parameters and the substrate materials used for each lens in the solid-state lidar RX lens in this embodiment are shown in Table 4:

[0138] Table 4

[0139]

[0140] In this embodiment, the aspheres of the aspherical lenses (the second lens L2, the third lens L3, and the sixth lens L6) satisfy the following aspherical formula:

[0141]

[0142] where Z is the sagittal height, c is the reciprocal of the radius of curvature R, y is the radial coordinate, k is the conic quadratic coefficient, and A2, A3, A4, A5, A6, A7, and A8 are the aspherical high-order coefficients. The specific aspherical parameters of the second lens L2, the third lens L3, and the sixth lens L6 are shown in Table 5:

[0143] Table 5

[0144] k <![CDATA[A2]]> <![CDATA[A3]]> <![CDATA[A4]]> <![CDATA[A5]]> <![CDATA[A6]]> <![CDATA[A7]]> <![CDATA[A8]]> L2S1 -17.62 1.62E-03 -1.09E-04 1.57E-05 -6.05E-07 -5.57E-08 0 0 L2S2 -15.65 8.47E-04 -4.27E-04 4.19E-05 -5.86E-06 2.62E-07 0 0 L3S1 -199.01 -9.93E-04 2.19E-04 -8.99E-05 8.54E-06 -4.87E-07 0 0 L3S2 0.66 -7.95E-04 -3.32E-05 -7.46E-07 -5.89E-08 1.52E-09 0 0 L6S1 170.79 -1.89E-03 -2.01E-05 5.70E-07 8.41E-08 5.95E-10 0 0 L6S2 2.18 -2.38E-04 -1.49E-05 1.16E-06 -1.95E-08 1.70E-10 0 0

[0145] Among them, the surface numbers L2S1, L3S1, and L6S1 respectively represent the object sides of the second lens L2, the third lens L3, and the sixth lens L6, and the surface numbers L2S2, L3S2, and L6S2 respectively represent the image sides of the second lens L2, the third lens L3, and the sixth lens L6.

[0146] It can be understood that the aspheres of the aspherical lenses in the solid-state lidar RX lens in this embodiment can use the aspheres constrained by the above aspherical formula, or can use the aspheres constrained by other aspherical formulas, and the present application does not make a limitation.

[0147] Figure 5 Describes the SPOTSIZE diagram (spot size diagram) of the solid-state lidar RX lens designed in the lens combination manner of Embodiment 1. The SPOT SIZE diagram is mainly used to evaluate the distribution size and shape of the spot on the image plane, and reflects the focusing ability of the system on the point light source or the influence of aberrations (such as spherical aberration, coma, astigmatism, etc.). In the SPOT SIZE diagram, RMSRadius represents the spot result after root mean square processing of the spot (unit: micrometer), and this result is closer to the spot value in actual production. GEO Radius represents the distance between the two farthest points of the spot (unit: micrometer). Specifically, it can be seen from the figure that GEO Radius is less than 3*(RMS Radius), indicating that the lens design result is relatively good. Moreover, in the process of the field of view from the center to the edge in the infrared band, the spot size shows a gradually increasing trend. When the half field of view angle is 75 degrees, RMS Radius is less than 4um, which can ensure the large field of view resolution for an image sensor chip with a pixel size less than 8 micrometers. When the half field of view angle is 0 degrees, RMS Radius is less than 1.7um, which can ensure the paraxial resolution for an image sensor chip with a pixel size less than 5 micrometers.

[0148] Figure 6 Describes the field curvature diagram and distortion diagram of the solid-state lidar RX lens designed in the lens combination manner of Embodiment 1 from left to right in sequence.

[0149] Specifically, in the field curvature diagram, the abscissa represents the offset (unit: mm), and the ordinate represents the field of view angle (unit: degree). Among them, the S curve represents the sagittal field curvature at a wavelength of 905nm, and the T curve represents the meridional field curvature at a wavelength of 905nm. It can be known from the field curvature diagram that the field curvature of the solid-state lidar RX lens in this embodiment is within 0.04mm, indicating that the field curvature and astigmatism of each field of view have been well corrected, so that clear imaging can be obtained at both the field of view center and the edge.

[0150] In the distortion graph, the abscissa represents the distortion value (unit: %), and the ordinate represents the field of view angle (unit: degree). It can be seen from the distortion graph that the optical distortion is less than 75% within the field of view angle of 150 degrees, which matches the distortion at the transmitting end and can eliminate systematic errors to a certain extent.

[0151] In summary, the optical lens in this embodiment adopts three spherical lenses and three aspherical lenses. By combining the positive and negative optical powers and effectively distributing the optical power through the aspherical lenses, the imaging quality of the lens is improved. The overall structure is compact, and at the same time, the overall optical length TTL is less than 50 mm, which can achieve the purpose of miniaturization. In addition, a large aperture configuration can be realized to meet the clear imaging under low light conditions.

[0152] Embodiment Three:

[0153] As Figure 7 shown, a solid-state lidar RX lens provided by the present invention is shown. In this embodiment, the solid-state lidar RX lens includes a first lens L1 with a negative optical power, a second lens L2 with a positive optical power, an aperture stop STO, a third lens L3 with a negative optical power, a fourth lens L4 with a positive optical power, a fifth lens L5 with a positive optical power, a filter IR, and a sixth lens L6 with a positive optical power, which are arranged in sequence along the optical axis direction. The imaging of the lens is on the image plane IMG.

[0154] In terms of the shape and structure, the first lens L1 is a convex-concave spherical lens, the second lens L2 is a concave-convex aspherical lens, the third lens L3 is a concave-convex aspherical lens, the fourth lens L4 is a biconvex spherical lens, the fifth lens L5 is a biconvex spherical lens, and the sixth lens L6 is a convex-concave aspherical lens; among them, the object side and the image side of the second lens L2, the third lens L3, and the sixth lens L6 are both rotationally symmetric aspheres.

[0155] In terms of the physical dimensions, the physical semi-apertures of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are 6.45 mm, 2.69 mm, 2.22 mm, 4.88 mm, 5.89 mm, and 5.23 mm, respectively.

[0156] In terms of the optical parameters, the total effective focal length f of the lens is 3.01 mm, the entrance pupil diameter is 2.45 mm, the ratio of the true semi-image height IH corresponding to the maximum field of view angle to the total effective focal length f of the lens is 1.06, and the ratio of the overall optical length TTL to the true semi-image height IH corresponding to the maximum field of view angle is 15.625.

[0157] Specifically, the specific parameters and the substrate materials used for each lens in the solid-state lidar RX lens in this embodiment are shown in Table 6:

[0158] Table 6

[0159]

[0160]

[0161] In this embodiment, the aspheres of the aspherical lenses (the second lens L2, the third lens L3, and the sixth lens L6) satisfy the following aspherical formula:

[0162]

[0163] where Z is the sag, c is the reciprocal of the radius of curvature R, y is the radial coordinate, k is the conic coefficient, A2, A3, A4, A5, A6, A7, A8 are the aspherical high-order coefficients, and the specific aspherical parameters of the second lens L2, the third lens L3, and the sixth lens L6 are shown in Table 7:

[0164] Table 7

[0165]

[0166] where the surface numbers L2S1, L3S1, and L6S1 respectively represent the object sides of the second lens L2, the third lens L3, and the sixth lens L6, and the surface numbers L2S2, L3S2, and L6S2 respectively represent the image sides of the second lens L2, the third lens L3, and the sixth lens L6.

[0167] It can be understood that the aspheres of the aspherical lenses in the RX lens of the solid-state lidar in this embodiment can use the aspheres constrained by the above aspherical formula or the aspheres constrained by other aspherical formulas, and the present application does not make any limitations.

[0168] Figure 8Describes the SPOT SIZE diagram (spot size diagram) of the RX lens of a solid-state lidar designed in the lens combination mode of Embodiment 1. The SPOT SIZE diagram is mainly used to evaluate the distribution size and shape of the spot on the image plane, and reflects the focusing ability of the system on the point light source or the influence of aberrations (such as spherical aberration, coma, astigmatism, etc.). In the SPOT SIZE diagram, RMSRadius represents the spot result after root mean square processing (unit: micrometer), and this result is closer to the spot value in actual production. GEO Radius represents the distance between the two farthest points of the spot (unit: micrometer). Specifically, it can be seen from the figure that GEO Radius is less than 3*(RMS Radius), indicating that the lens design result is relatively good. Moreover, in the process of the field of view from the center to the edge in the infrared band, the spot size shows a gradually increasing trend. When the half field of view angle is 75 degrees, RMS Radius is less than 6um, which can ensure the large field of view resolution for an image sensor chip with a pixel size less than 10 micrometers. When the half field of view angle is 0 degrees, RMS Radius is less than 1.6um, which can ensure the paraxial resolution for an image sensor chip with a pixel size less than 4um.

[0169] Figure 9 From left to right, it sequentially describes the field curvature diagram and distortion diagram of the RX lens of a solid-state lidar designed in the lens combination mode of Embodiment 1.

[0170] Specifically, in the field curvature diagram, the abscissa represents the offset (unit: mm), and the ordinate represents the field of view angle (unit: degree). Among them, the S curve represents the sagittal field curvature at a wavelength of 905nm, and the T curve represents the meridional field curvature at a wavelength of 905nm. It can be known from the field curvature diagram that the field curvatures of the RX lens of the solid-state lidar in this embodiment are all within 0.04mm, indicating that the field curvatures and astigmatisms of each field of view have been well corrected, so that clear imaging can be obtained at both the center and the edge of the field of view.

[0171] In the distortion diagram, the abscissa represents the distortion value (unit: %), and the ordinate represents the field of view angle (unit: degree). It can be known from the distortion diagram that the optical distortion is less than 74.5% within a field of view angle of 150 degrees, which matches the distortion of the transmitting end and can eliminate systematic errors to a certain extent.

[0172] In summary, the optical lens in this embodiment adopts three spherical lenses and three aspherical lenses. By matching the optical powers with negative, positive, and negative values and effectively distributing the optical power through the aspherical lenses, the imaging quality of the lens is improved. The overall structure is compact, and at the same time, the overall optical length TTL is less than 50mm, which can achieve the purpose of miniaturization. In addition, a large aperture configuration can be realized to meet the clear imaging under low light conditions.

[0173] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0174] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the appended claims.

Claims

1. A solid-state lidar RX lens, characterized in that, The solid-state lidar RX lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in sequence along the optical axis direction; The object side and the image side of the second lens, the third lens, and the sixth lens are both rotationally symmetric aspheres; The optical powers of the six groups of lenses are, in sequence along the arrangement direction, negative optical power, positive optical power, negative optical power, positive optical power, positive optical power, positive optical power; or, the optical powers of the six groups of lenses are, in sequence along the arrangement direction, negative optical power, positive optical power, positive optical power, positive optical power, positive optical power, positive optical power; The solid-state lidar RX lens satisfies the following optical parameter conditions: 0.08 < |f1 / f2| < 0.25; 1.50 < |f2 / f3| < 7.90; 0.50 < |f3 / f4| < 1.99; 0.2 < |f4 / f5| < 2.22; 0.30 < |f5 / f6| < 0.95; 150° < FOV < 170°; Wherein, f1, f2, f3, f4, f5, and f6 are the effective focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens respectively, with the unit of millimeter, and FOV is the field of view angle of the solid-state lidar RX lens.

2. The solid-state lidar RX lens according to claim 1, characterized in that, The solid-state lidar RX lens further includes an aperture stop, and the aperture stop is located between the second lens and the third lens.

3. The solid-state lidar RX lens according to claim 2, characterized in that, The solid-state lidar RX lens satisfies the following optical parameter conditions: 45 < TTL < 50; Wherein, TTL is the overall optical length of the solid-state lidar RX lens, with the unit of millimeter.

4. The solid-state lidar RX lens according to claim 3, wherein The solid-state lidar RX lens satisfies the following optical parameter conditions: 4.8 ≤ BFL ≤ 5.5; Wherein, BFL is the distance from the image side of the sixth lens to the image plane of the solid-state lidar RX lens on the optical axis, with the unit of millimeter.

5. The RX lens of the solid-state lidar according to claim 3, characterized in that, The solid-state lidar RX lens satisfies the following optical parameter conditions: 1.0 < IH / f < 1.2; Wherein, IH is the actual semi-image height of the solid-state lidar RX lens, and f is the total effective focal length of the solid-state lidar RX lens, with the unit of millimeter.

6. The RX lens of the solid-state lidar according to claim 5, characterized in that The solid-state lidar RX lens satisfies the following optical parameter conditions: 12 < TTL / IH < 17; Wherein, IH is the actual semi-image height of the solid-state lidar RX lens, with the unit of millimeter.

7. The solid-state lidar RX lens according to claim 1, wherein The solid-state lidar RX lens satisfies the following optical parameter conditions: 0.5° < CRA < 2.0°; Wherein, CRA is the maximum principal ray incident angle of the image plane of the solid-state lidar RX lens.

8. The solid-state lidar RX lens according to claim 1, wherein The solid-state lidar RX lens satisfies the following optical parameter conditions: 2.05 < DM1 / DM2 < 2.75; 0.93 < DM2 / DM3 < 1.75; 0.50 < DM3 / DM4 < 1.05; 0.70 < DM4 / DM5 < 1.15; 0.92 < DM5 / DM6 < 1.15; Among them, DM1, DM2, DM3, DM4, DM5, and DM6 are the effective apertures of the object sides of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens respectively, with the unit of millimeter.

9. The solid-state lidar RX lens according to claim 8, wherein The RX lens of the solid-state lidar satisfies the following optical parameter conditions: 1.15 ≤ Fno ≤ 1.30; Among them, Fno is the aperture size of the RX lens of the solid-state lidar.

10. The solid-state lidar RX lens according to any one of claims 1 to 9, characterized in that, The working wavelength band of the RX lens of the solid-state lidar is 885 nm to 925 nm, and the main wavelength is 905 nm.

Images