Receiving lens

Abstract

The utility model provides a receiving lens, which belongs to the technical field of optical imaging and comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged along the direction of an optical axis. The focal powers of the five groups of lenses are negative focal power, positive focal power, negative focal power, positive focal power and positive focal power in sequence along the arrangement direction, or the object side surfaces and the image side surfaces of the first lens and the third lens are rotationally symmetrical aspheric surfaces; the focal powers of the five groups of lenses are negative focal power, negative focal power, positive focal power, positive focal power and positive focal power in sequence along the arrangement direction; wherein the base materials of the five groups of lenses are all high-temperature-resistant materials, and the receiving lens also meets set optical parameter conditions. According to the utility model, under the condition of ensuring that the receiving lens satisfies a large field angle, the requirements of large aperture, small size and high resolution capability can be satisfied at the same time.

Description

Technical Field

[0001] This utility model relates to the field of optical imaging technology, and in particular to a receiving lens. Background Technology

[0002] In recent years, with the increase in photosensitive area and improvement in low-light performance of CMOS (Complementary Metal Oxide Semiconductor) image sensors, coupled with breakthroughs in DSP (Digital Signal Processing) technology, optical imaging systems are showing a trend towards miniaturization and high performance in applications such as automotive ADAS (Advanced Driving Assistant Systems), intelligent security, and machine vision. Among these developments, ensuring that receiving lenses can achieve a large field of view while maintaining a large aperture, small size, and high resolution has become a current research focus.

[0003] In existing receiver lens designs, for example, patent document CN112099193A discloses a small TOF (Time of Flight) lens, which adopts a hybrid structure including two plastic aspherical lenses and four glass spherical lenses. This TOF lens has a large optical length and insufficient space utilization. Moreover, due to the use of plastic aspherical lenses, it will generate a large amount of defocus in high-temperature environments, resulting in poor resolution. Another example is patent document CN113311571A, which discloses a small-volume vehicle-mounted TOF lens. It achieves an optical length of 10mm through five all-glass lenses, while having low distortion. However, its structure is limited by the Petzwald field curvature correction condition, which forces its half field of view to be less than 10 degrees.

[0004] The aforementioned technical bottlenecks have led to a contradiction in the practical application of existing receiving lenses: "a large field of view and a small size cannot be achieved simultaneously" and "high resolution and weather resistance are mutually restrictive," which seriously restricts the application and development of receiving lenses. Utility Model Content

[0005] Based on this, the purpose of this utility model is to provide a receiving lens that ensures that the receiving lens meets the requirements of a large field of view, large aperture, small size, and high resolution at the same time.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A receiving lens includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the optical axis. The object-side and image-side surfaces of the first lens are both rotationally symmetric aspherical surfaces, and the object-side and image-side surfaces of the fifth lens are both rotationally symmetric aspherical surfaces. The optical power of the five lenses, arranged sequentially along the direction of arrangement, is negative optical power, positive optical power, negative optical power, positive optical power, and positive optical power. Alternatively, the object-side and image-side surfaces of the first lens are both rotationally symmetric aspherical surfaces, and the object-side and image-side surfaces of the third lens are both rotationally symmetric aspherical surfaces. The optical power of the five lenses, arranged sequentially along the direction of arrangement, is negative optical power, negative optical power, positive optical power, positive optical power, and positive optical power. The substrate material of all five lenses is a high-temperature resistant material. The receiving lens also satisfies the following optical parameter conditions:

[0007] 0.3 < |f1 / f2| < 1.6;

[0008] 0.3 < |f2 / f3| < 2.5;

[0009] 0.2 < |f3 / f4| < 2.55;

[0010] 0.4 < |f4 / f5| < 1.8;

[0011] 20≤TTL≤25.5;

[0012] 90° <FOV<120°;

[0013] Wherein, f1, f2, f3, f4, and f5 are the effective focal lengths of the first lens, the second lens, the third lens, the fourth lens, and the fifth lens, respectively; TTL is the total optical length of the receiving lens in millimeters; and FOV is the field of view of the receiving lens.

[0014] In addition, the receiving lens according to the present invention may also have the following additional technical features:

[0015] Furthermore, the receiving lens also includes an aperture stop; wherein, when the object-side surface and image-side surface of the first lens are both rotationally symmetric aspherical surfaces, and the object-side surface and image-side surface of the fifth lens are both rotationally symmetric aspherical surfaces, the aperture stop is disposed between the first lens and the second lens; when the object-side surface and image-side surface of the first lens are both rotationally symmetric aspherical surfaces, and the object-side surface and image-side surface of the third lens are both rotationally symmetric aspherical surfaces, the aperture stop is disposed between the second lens and the third lens.

[0016] Furthermore, the receiving lens satisfies the following optical parameter conditions:

[0017] 0.45 <SL / TTL<0.85;

[0018] Wherein, SL is the distance from the aperture stop to the image plane of the receiving lens, in millimeters.

[0019] Furthermore, the receiving lens satisfies the following optical parameter conditions:

[0020] 0.125 <BFL / TTL<0.195;

[0021] Wherein, BFL is the distance on the optical axis from the image-side surface of the fifth lens to the image-side surface of the receiving lens, in millimeters.

[0022] Furthermore, the receiving lens satisfies the following optical parameter conditions:

[0023] 13.5°≤θ≤15°;

[0024] Wherein, θ is the maximum principal ray incident angle of the image plane of the receiving lens.

[0025] Furthermore, the receiving lens satisfies the following optical parameter conditions:

[0026] 2.1≤f≤3.5;

[0027] Where f is the total effective focal length of the receiving lens, in millimeters.

[0028] Furthermore, the receiving lens satisfies the following optical parameter conditions:

[0029] 9≤TTL / IH≤13;

[0030] Wherein, IH is the target surface half-image height of the receiving lens, in millimeters.

[0031] Furthermore, the receiving lens satisfies the following optical parameter conditions:

[0032] 9≤SD1≤10;

[0033] 4≤SD5≤10;

[0034] Wherein, SD1 is the physical aperture of the first lens, and SD5 is the physical aperture of the fifth lens, in millimeters.

[0035] Furthermore, the receiving lens satisfies the following optical parameter conditions:

[0036] 1.15≤Fno≤1.23;

[0037] Wherein, Fno is the aperture size of the receiving lens.

[0038] Furthermore, the operating wavelength of the receiving lens is 905nm to 950nm, and the main wavelength is 940nm.

[0039] The beneficial effects of this utility model include at least the following:

[0040] 1. By precisely allocating the optical power of five lenses (either a negative-positive-negative-positive-positive or a negative-negative-positive-positive-positive architecture), combined with a specific aspherical layout (aspherical first / fifth lens or aspherical first / third lens), and through optical path optimization, a field of view of 90 to 120 degrees can be achieved with a shorter total optical length, solving the dual requirements of wide-angle imaging and device miniaturization in fields such as automotive. 2. All five lens groups are made of high-temperature resistant materials, and with the aspherical tolerance sensitivity control design, thermal stability is improved compared to solutions containing plastic lenses, especially at high temperatures. In the working environment, the lens has a low defocus amount. At the same time, by constraining the focal length ratio of the lens, the field curvature and spherical aberration can be effectively balanced to meet the precision ranging requirements of intelligent driving systems under high-temperature conditions. 3. By controlling the ratio of SL to BFL, the back focal length can be shortened while ensuring the flatness of the imaging surface. At the same time, combined with the reasonable design of the maximum principal ray incident angle of the image plane, the uniformity of illumination on the image plane can be improved, and the edge response sensitivity of the image sensor can be enhanced. In addition, the large aperture design can also improve the relative illumination, support clear imaging in low-light environments, and expand the applicable scenarios of the lens. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the receiving lens in Embodiment 1 of this utility model;

[0042] Figure 2 This is an MTF curve of the receiving lens in Embodiment 1 of this utility model;

[0043] Figure 3 The field curvature and distortion diagrams of the receiving lens in Embodiment 1 of this utility model are shown.

[0044] Figure 4 This is a SPOT SIZE diagram of the receiving lens in Embodiment 1 of this utility model;

[0045] Figure 5 This is a schematic diagram of the receiving lens in Embodiment 2 of this utility model;

[0046] Figure 6 This is an MTF curve of the receiving lens in Embodiment 2 of this utility model;

[0047] Figure 7 The field curvature and distortion diagrams of the receiving lens in Embodiment 2 of this utility model are shown.

[0048] Figure 8This is a SPOT SIZE diagram of the receiving lens in Embodiment 2 of this utility model;

[0049] Figure 9 This is a schematic diagram of the receiving lens in Embodiment 3 of this utility model;

[0050] Figure 10 This is an MTF curve of the receiving lens in Embodiment 3 of this utility model;

[0051] Figure 11 The field curvature and distortion diagrams of the receiving lens in Embodiment 3 of this utility model are shown.

[0052] Figure 12 This is a SPOT SIZE diagram of the receiving lens in Embodiment 3 of this utility model;

[0053] Figure 13 This is a schematic diagram of the receiving lens in Embodiment 4 of this utility model;

[0054] Figure 14 This is an MTF curve of the receiving lens in Embodiment 4 of this utility model;

[0055] Figure 15 The field curvature and distortion diagrams of the receiving lens in Embodiment 4 of this utility model are shown.

[0056] Figure 16 This is a SPOT SIZE diagram of the receiving lens in Embodiment 4 of this utility model;

[0057] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this utility model. Detailed Implementation

[0058] To facilitate understanding of this utility model, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of this utility model are shown in the drawings. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this utility model will be more thorough and complete.

[0059] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of this application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0060] In the accompanying drawings of this application, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly drawn to scale.

[0061] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity 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 location of the concaveness 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 subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0062] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising" used herein, when used in this specification, indicate 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. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplarily" is intended to refer to an example or illustration.

[0063] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0064] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0065] The features, principles and other aspects of this application are described in detail below.

[0066] Please refer to Figure 1 , Figure 5 , Figure 9 , Figure 13This invention provides a receiving lens comprising a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5 arranged sequentially along the optical axis. The object-side and image-side surfaces of the first lens L1 and the fifth lens L5 are both rotationally symmetric aspherical surfaces. The optical power of the five lenses, arranged sequentially along the optical axis, is negative, positive, negative, positive, and positive. Alternatively, the object-side and image-side surfaces of the first lens L1 and the third lens L3 are both rotationally symmetric aspherical surfaces, and the optical power of the five lenses, arranged sequentially along the optical axis, is negative, negative, positive, positive, and positive. The substrate material of all five lenses is a high-temperature resistant material, thus ensuring good high-temperature resistance.

[0067] In addition, the receiving lens provided in this application also meets the following optical parameter conditions:

[0068] 0.3 < |f1 / f2| < 1.6;

[0069] 0.3 < |f2 / f3| < 2.5;

[0070] 0.2 < |f3 / f4| < 2.55;

[0071] 0.4 < |f4 / f5| < 1.8;

[0072] 20≤TTL≤25.5;

[0073] 90° <FOV<120°;

[0074] Where f1, f2, f3, f4, and f5 are the effective focal lengths of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5, respectively; TTL is the total optical length of the receiving lens in millimeters; and FOV is the field of view of the receiving lens.

[0075] When the receiving lens provided in this application meets the above conditions, the receiving lens has good imaging effect and small distortion. Furthermore, by reasonably setting the focal length and optical power, the overall light trend can be adjusted, and the aperture of the head and tail of the lens can be expanded as much as possible, which helps to ensure high resolution and high depth of field under the condition of large aperture. In addition, by reasonably allocating the optical power to keep the total length of the lens within a small range, the compactness of the lens can be achieved, leaving more design space for the optical engine structure, greatly compressing the lens size, and laying the foundation for realizing the miniaturization, portability and lightweight of the product.

[0076] To achieve a balance between high imaging quality and compact structure, the receiving lens provided in this application preferably also meets the optical parameter conditions shown in Table 1:

[0077] Table 1

[0078] <![CDATA[n d1 ]]> <![CDATA[n d2 ]]> <![CDATA[n d3 ]]> <![CDATA[n d4 ]]> <![CDATA[n d5 ]]> 1.69±5％ 1.59±10％ 1.70±15％ 1.75±15％ 1.70±15％ <![CDATA[v d1 ]]> <![CDATA[v d2 ]]> <![CDATA[v d3 ]]> <![CDATA[v d4 ]]> <![CDATA[v d5 ]]> 53.2±5％ 58±45％ 53±60％ 47±10％ 37±25％

[0079] Where, n d1、 n d2、 n d3、 n d4、 n d5 The refractive indices of lenses L1 through L5 are, in order, v d1、 v d2、 v d3、 v d4、 v d5 The Abbe numbers are, in order, those of the first lens L1 to the fifth lens L5.

[0080] In some optional embodiments, the receiving lens further includes an aperture stop STO. Specifically, when both the object-side and image-side surfaces of the first lens L1 and the fifth lens L5 are rotationally symmetric aspherical surfaces, the aperture stop STO is located between the first lens L1 and the second lens L5; when both the object-side and image-side surfaces of the first lens L1 and the third lens L3 are rotationally symmetric aspherical surfaces, the aperture stop STO is located between the second lens L2 and the third lens L3.

[0081] In some optional embodiments, the receiving lens also satisfies the following optical parameter conditions:

[0082] 0.45 <SL / TTL<0.85;

[0083] Wherein, SL is the distance from the aperture stop STO to the image plane of the receiving lens, in millimeters.

[0084] When the receiving lens provided in this application satisfies the above conditions, the receiving lens has good compactness, aberration correction capability, and mechanical adaptability.

[0085] In some optional embodiments, the receiving lens also satisfies the following optical parameter conditions:

[0086] 0.125 <BFL / TTL<0.195;

[0087] Wherein, BFL is the distance on the optical axis from the image-side surface of the fifth lens to the image-side surface of the receiving lens, in millimeters.

[0088] When the receiving lens provided in this application satisfies the above-mentioned conditions, a balance can be found between minimizing TTL and meeting the functional requirements of BFL by combining the aperture stop position, so as to balance coma and distortion and achieve a unity of high imaging performance and manufacturability.

[0089] In some optional embodiments, the receiving lens also satisfies the following optical parameter conditions:

[0090] 13.5°≤θ≤15°;

[0091] Wherein, θ is the maximum principal ray incident angle of the image plane of the receiving lens.

[0092] When the receiving lens provided in this application satisfies the above-mentioned conditions, the lens has less astigmatism, field curvature, and distortion.

[0093] In some optional embodiments, the receiving lens also satisfies the following optical parameter conditions:

[0094] 2.1≤f≤3.5;

[0095] Where f is the total effective focal length of the receiving lens, in millimeters.

[0096] In some optional embodiments, the receiving lens satisfies the following optical parameter conditions:

[0097] 9≤TTL / IH≤13;

[0098] Wherein, IH is the target surface half-image height of the receiving lens, in millimeters.

[0099] When the receiving lens provided in this application satisfies the above conditions, the system compactness and field of view coverage can be balanced, ensuring that the lens is miniaturized while achieving a large field of view.

[0100] In some alternative embodiments, the receiving lens satisfies the following optical parameter conditions:

[0101] 9≤SD1≤10;

[0102] 4≤SD5≤10;

[0103] Wherein, SD1 is the physical aperture of the first lens L1, and SD5 is the physical aperture of the fifth lens L5, in millimeters.

[0104] When the receiving lens provided in this application meets the above conditions, the large aperture at the head and tail of the lens helps to achieve the requirements of high resolution and high depth of field while ensuring a large aperture.

[0105] In some optional embodiments, the receiving lens satisfies the following optical parameter conditions:

[0106] 1.15≤Fno≤1.23;

[0107] Wherein, Fno is the aperture size of the receiving lens.

[0108] When the receiving lens provided in this application meets the above conditions, it can still achieve clear imaging in low-light environments. In the field of security monitoring, it significantly improves the detection effect in the dark. In the field of lidar, it can also achieve detection at a longer distance.

[0109] In some optional embodiments, the receiving lens operates in the 905nm–950nm band, with a main wavelength of 940nm.

[0110] The following will combine Figures 1 to 16 The present application provides more detailed descriptions of specific, but not limiting, examples of its embodiments. It should be noted that the following embodiments primarily analyze light with a reference wavelength of 940 nm.

[0111] Example 1:

[0112] like Figure 1 As shown, this utility model provides a receiving lens. In this embodiment, the receiving lens includes a first lens L1 with negative optical power, an aperture stop STO, a second lens L2 with positive optical power, a third lens L3 with negative optical power, a fourth lens L4 with positive optical power, a fifth lens L5 with positive optical power, and a filter IR, arranged sequentially along the optical axis. The lens images onto the image plane IMG.

[0113] In terms of shape and structure, the first lens L1 is a meniscus aspherical lens, the second lens L2 is a spherical lens with both the object-side and image-side surfaces being convex, the third lens L3 is a spherical lens with both the object-side and image-side surfaces being concave, the fourth lens L4 is a spherical lens with both the object-side and image-side surfaces being convex, and the fifth lens L5 is an aspherical lens with both the object-side and image-side surfaces being convex. Among them, the object-side and image-side surfaces of the first lens L1 are both rotationally symmetric aspherical surfaces, and the object-side and image-side surfaces of the fifth lens L5 are both rotationally symmetric aspherical surfaces.

[0114] In terms of physical dimensions, the physical half-apertures of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are 4.74mm, 2.75mm, 2.77mm, 2.81mm, and 2.21mm, respectively. The physical apertures of the five lens groups generally show a decreasing trend along the optical axis, which can realize the miniaturization design of the lens.

[0115] In terms of optical parameters, the lens has a total effective focal length f of 2.39mm, an entrance pupil diameter of 1.96mm, a true half-image height IH corresponding to the maximum field of view of 2.31mm, and a ratio of total optical length TTL to true half-image height IH corresponding to the maximum field of view of 9.52.

[0116] Specifically, the specific parameters of each lens in the receiving lens of this embodiment and the substrate material used are shown in Table 2:

[0117] Table 2

[0118]

[0119]

[0120] In Table 2, high-temperature resistant glass was selected as the substrate material for all lenses, enabling them to be used in high-temperature environments, such as automotive environments. Furthermore, considering the possibility of the first lens L1 being exposed to air, a lens made of D-LAK6 material, known for its high hardness and low abrasion resistance, was chosen. Additionally, the assembly eccentricity of the fifth lens L5 is highly sensitive to performance; therefore, a single-head assembly was adopted in the design. This allows for better control of assembly eccentricity and tilt during the manufacturing process, thereby reducing process requirements, improving production yield, and ultimately reducing costs.

[0121] In this embodiment, the aspherical surfaces of the aspherical lenses (first lens L1 and fifth lens L5) satisfy the following aspherical formula:

[0122]

[0123] Where Z is the sag, c is the reciprocal of the radius of curvature R, y is the radial coordinate, k is the conic conic coefficient, and A2, A3, A4, A5, A6, A7, and A8 are higher-order aspherical coefficients. The specific aspherical parameters of the first lens L1 and the fifth lens L5 are shown in Table 3.

[0124] Table 3

[0125] k <![CDATA[A2]]> <![CDATA[A3]]> <![CDATA[A4]]> <![CDATA[A5]]> <![CDATA[A6]]> <![CDATA[A7]]> <![CDATA[A8]]> L1S1 -50.32 0 9.69E-03 -1.13E-03 9.199E-05 -5.14E-06 1.83E-07 -3.18E-11 L1S2 -2.16 0 0.0217 -2.08E-03 1.49E-04 -5.87E-06 -3.66E-08 0 L5S1 -1.57 0 9.69E-03 -1.13E-03 -5.49E-6 0 0 0 L5S2 -100 0 0.0217 -2.08E-03 8.61E-06 0 0 0

[0126] Among them, surface numbers L1S1 and L5S1 represent the object side surface of the first lens L1 and the fifth lens L5, respectively, and surface numbers L1S2 and L5S2 represent the image side surface of the first lens L1 and the fifth lens L5, respectively.

[0127] It is understood that the aspherical surfaces of each aspherical lens in the receiving lens in this embodiment can be aspherical surfaces constrained by the above-mentioned aspherical formula, or aspherical surfaces constrained by other aspherical formulas, and this application does not limit them.

[0128] Figure 2 The MTF curve of the receiving lens designed with the lens combination of Embodiment 1 is described.

[0129] The horizontal axis represents spatial frequency (in lp / mm), and the vertical axis represents MTF value. The MTF curve can represent the lens imaging modulation at different spatial frequencies in various fields of view. Figure 2 As can be seen from the MTF curve, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, which indicates that the receiving lens has good imaging resolution in both low and high frequency conditions.

[0130] Figure 3 The field curvature and distortion diagrams of the receiving lens designed with the lens combination of Embodiment 1 are shown from left to right.

[0131] Specifically, in the field curvature diagram, the horizontal axis represents the offset (in mm), and the vertical axis represents the field of view (in degrees). The S-curve represents the sagittal field curvature at a wavelength of 940 nm, and the T-curve represents the meridional field curvature at a wavelength of 940 nm. As can be seen from the field curvature diagram, the field curvature of the receiving lens in this embodiment is within 0.03 mm, indicating that the field curvature and astigmatism of each field of view are well corrected, resulting in clear imaging at both the center and edges of the field of view.

[0132] In the distortion diagram, the horizontal axis represents the distortion value (in %), and the vertical axis represents the field of view angle (in degrees). As can be seen from the distortion diagram, the optical distortion of each field of view is within 5%, indicating that the image deformation caused by the main beam is small, resulting in excellent imaging quality of the system.

[0133] Figure 4 This describes the spot size diagram of the receiving lens designed with the lens combination of Example 1. The spot size diagram is mainly used to evaluate the size and shape of the spot distribution on the image plane, reflecting the system's focusing ability on a point light source or the impact of aberrations (such as spherical aberration, coma, astigmatism, etc.). In the spot size diagram, the root mean square distance (RMS Radius) of all tracing rays to the center of the spot is controlled within 7 μm in the infrared band.

[0134] In summary, the optical lens in this embodiment uses aspherical lenses to correct spherical aberration and distortion, which can reduce the number of lenses required for a large image plane under a wide field of view. At the same time, the physical aperture of the five lens groups generally decreases along the optical axis, which can achieve a miniaturized lens design. In addition, the lens can effectively control the light path by combining positive and negative optical powers, achieving a larger working distance. While ensuring that the receiving lens meets the requirements of a wide field of view, it also meets the requirements of a large aperture, small size, and high resolution.

[0135] Example 2:

[0136] like Figure 5 As shown, this utility model provides a receiving lens. In this embodiment, the receiving lens includes a first lens L1 with negative optical power, a second lens L2 with negative optical power, an aperture stop STO, a third lens L3 with positive optical power, a fourth lens L4 with positive optical power, a fifth lens L5 with positive optical power, and an IR filter, arranged sequentially along the optical axis. The lens images onto the image plane IMG.

[0137] In terms of shape and structure, the first lens L1 is a meniscus aspherical lens, the second lens L2 is a meniscus spherical lens, the third lens L3 is an aspherical lens with both the object-side and image-side surfaces being convex, the fourth lens L4 is a meniscus spherical lens, and the fifth lens L5 is a spherical lens with both the object-side and image-side surfaces being convex. Among them, the object-side and image-side surfaces of the first lens L1 are both rotationally symmetric aspherical surfaces, and the object-side and image-side surfaces of the third lens L3 are both rotationally symmetric aspherical surfaces.

[0138] In terms of physical dimensions, the physical half-apertures of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are 4.41mm, 1.72mm, 2.29mm, 4.56mm, and 4.60mm, respectively.

[0139] In terms of optical parameters, the lens has a total effective focal length f of 2.36mm, an entrance pupil diameter of 2mm, a true half-image height IH corresponding to the maximum field of view of 2.31mm, and a ratio of total optical length TTL to true half-image height IH corresponding to the maximum field of view of 9.91.

[0140] Specifically, the specific parameters of each lens in the receiving lens of this embodiment and the substrate material used are shown in Table 4:

[0141] Table 4

[0142]

[0143] In Table 4, high-temperature resistant glass was selected as the substrate material for all lenses, enabling them to be used in high-temperature environments, such as automotive environments. Furthermore, considering the possibility of the first lens L1 being exposed to air, D-LAK6 material, known for its high hardness and low abrasion resistance, was chosen. Additionally, the assembly eccentricity of the fifth lens L5 is highly sensitive to performance; therefore, a single-head assembly was adopted in the design. This allows for better control of assembly eccentricity and tilt during the manufacturing process, thereby reducing process requirements, improving production yield, and ultimately reducing costs.

[0144] In this embodiment, the aspherical surfaces of the aspherical lenses (first lens L1 and third lens L3) satisfy the following aspherical formula:

[0145]

[0146] Where Z is the sag, c is the reciprocal of the radius of curvature R, y is the radial coordinate, k is the conic conic coefficient, and A2, A3, A4, A5, A6, A7, and A8 are higher-order aspherical coefficients. The specific aspherical parameters of the first lens L1 and the third lens L3 are shown in Table 5.

[0147] Table 5

[0148]

[0149] Among them, surface numbers L1S1 and L3S1 represent the object side surface of the first lens L1 and the third lens L3, respectively, and surface numbers L1S2 and L3S2 represent the image side surface of the first lens L1 and the third lens L3, respectively.

[0150] It is understood that the aspherical surfaces of each aspherical lens in the receiving lens in this embodiment can be aspherical surfaces constrained by the above-mentioned aspherical formula, or aspherical surfaces constrained by other aspherical formulas, and this application does not limit them.

[0151] Figure 6 The MTF curve of the receiving lens designed with the lens combination method of Embodiment 2 is described.

[0152] The horizontal axis represents spatial frequency (in lp / mm), and the vertical axis represents MTF value. The MTF curve can represent the lens imaging modulation at different spatial frequencies in various fields of view. Figure 6 As can be seen from the MTF curve, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, which indicates that the receiving lens has good imaging resolution in both low and high frequency conditions.

[0153] Figure 7 The field curvature diagram and distortion diagram of the receiving lens designed with the lens combination method of Embodiment 2 are described from left to right.

[0154] Specifically, in the field curvature diagram, the horizontal axis represents the offset (in mm), and the vertical axis represents the field of view (in degrees). The S-curve represents the sagittal field curvature at a wavelength of 940 nm, and the T-curve represents the meridional field curvature at a wavelength of 940 nm. As can be seen from the field curvature diagram, the field curvature of the receiving lens in this embodiment is within 0.03 mm, indicating that the field curvature and astigmatism of each field of view are well corrected, resulting in clear imaging at both the center and edges of the field of view.

[0155] In the distortion diagram, the horizontal axis represents the distortion value (in %), and the vertical axis represents the field of view angle (in degrees). As can be seen from the distortion diagram, the optical distortion of each field of view is within 4.8%, indicating that the image deformation caused by the main beam is small, resulting in excellent imaging quality of the system.

[0156] Figure 8 This describes the spot size diagram of the receiving lens designed with the lens combination of Example 1. The spot size diagram is mainly used to evaluate the size and shape of the spot distribution on the image plane, reflecting the system's focusing ability on a point light source or the impact of aberrations (such as spherical aberration, coma, astigmatism, etc.). In the spot size diagram, the root mean square distance (RMS Radius) of all tracing rays to the center of the spot is controlled within 4.5 μm in the infrared band.

[0157] In summary, the optical lens in this embodiment uses aspherical lenses to correct spherical aberration and distortion, which can reduce the number of lenses required for a large image plane under a wide field of view. At the same time, the physical aperture of the five lens groups generally decreases along the optical axis, which can achieve a miniaturized lens design. In addition, the lens can effectively control the light path by combining positive and negative optical powers, achieving a larger working distance. While ensuring that the receiving lens meets the requirements of a wide field of view, it also meets the requirements of a large aperture, small size, and high resolution.

[0158] Example 3:

[0159] like Figure 9 As shown, this utility model provides a receiving lens. In this embodiment, the receiving lens includes a first lens L1 with negative optical power, an aperture stop STO, a second lens L2 with positive optical power, a third lens L3 with negative optical power, a fourth lens L4 with positive optical power, a fifth lens L5 with positive optical power, and a filter IR, arranged sequentially along the optical axis. The lens images onto the image plane IMG.

[0160] In terms of shape and structure, the first lens L1 is a meniscus aspherical lens, the second lens L2 is a meniscus spherical lens, the third lens L3 is a meniscus aspherical lens, the fourth lens L4 is a meniscus spherical lens, and the fifth lens L5 is a meniscus spherical lens; among them, the object side and image side of the first lens L1 are both rotationally symmetric aspherical surfaces, and the object side and image side of the third lens L3 are both rotationally symmetric aspherical surfaces.

[0161] In terms of physical dimensions, the physical half-apertures of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are 4.95mm, 2mm, 3.8mm, 4.8mm, and 4.44mm, respectively.

[0162] In terms of optical parameters, the lens has a total effective focal length f of 2.39mm, an entrance pupil diameter of 2.1mm, a true half-image height IH corresponding to the maximum field of view of 2.31mm, and a ratio of total optical length TTL to true half-image height IH corresponding to the maximum field of view of 10.01.

[0163] Specifically, the specific parameters of each lens in the receiving lens of this embodiment and the substrate material used are shown in Table 6:

[0164] Table 6

[0165]

[0166] In Table 6, high-temperature resistant glass was selected as the substrate material for all lenses, enabling them to be used in high-temperature environments, such as automotive environments. Furthermore, considering the possibility of the first lens L1 being exposed to air, D-LAK6 material, known for its high hardness and low abrasion resistance, was chosen. Additionally, the assembly eccentricity of the fifth lens L5 is highly sensitive to performance; therefore, a single-head assembly was adopted in the design. This allows for better control of assembly eccentricity and tilt during the manufacturing process, thereby reducing process requirements, improving production yield, and ultimately reducing costs.

[0167] In this embodiment, the aspherical surfaces of the aspherical lenses (first lens L1 and third lens L3) satisfy the following aspherical formula:

[0168]

[0169] Where Z is the sag, c is the reciprocal of the radius of curvature R, y is the radial coordinate, k is the conic conic coefficient, and A2, A3, A4, A5, A6, A7, and A8 are higher-order aspherical coefficients. The specific aspherical parameters of the first lens L1 and the third lens L3 are shown in Table 7.

[0170] Table 7

[0171]

[0172] Among them, surface numbers L1S1 and L3S1 represent the object side surface of the first lens L1 and the third lens L3, respectively, and surface numbers L1S2 and L3S2 represent the image side surface of the first lens L1 and the third lens L3, respectively.

[0173] It is understood that the aspherical surfaces of each aspherical lens in the receiving lens in this embodiment can be aspherical surfaces constrained by the above-mentioned aspherical formula, or aspherical surfaces constrained by other aspherical formulas, and this application does not limit them.

[0174] Figure 10The MTF curve of the receiving lens designed with the lens combination method of Embodiment 3 is described.

[0175] The horizontal axis represents spatial frequency (in lp / mm), and the vertical axis represents MTF value. The MTF curve can represent the lens imaging modulation at different spatial frequencies in various fields of view. Figure 10 As can be seen from the MTF curve, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view. Especially under the condition of 111 lp / mm, the MTF is greater than 30%, which indicates that the lens has good imaging resolution in both low and high frequency conditions.

[0176] Figure 11 The field curvature and distortion diagrams of the receiving lens designed with the lens combination of Embodiment 1 are shown from left to right.

[0177] Specifically, in the field curvature diagram, the horizontal axis represents the offset (in mm), and the vertical axis represents the field of view (in degrees). The S-curve represents the sagittal field curvature at a wavelength of 940 nm, and the T-curve represents the meridional field curvature at a wavelength of 940 nm. As can be seen from the field curvature diagram, the field curvature of the receiving lens in this embodiment is all within 0.08 mm, indicating that the field curvature and astigmatism of each field of view are well corrected, resulting in clear imaging at both the center and edges of the field of view.

[0178] In the distortion diagram, the horizontal axis represents the distortion value (in %), and the vertical axis represents the field of view angle (in degrees). As can be seen from the distortion diagram, the optical distortion of each field of view is within 4.6%, indicating that the image deformation caused by the main beam is small, resulting in excellent imaging quality of the system.

[0179] Figure 12 This describes the spot size diagram of the receiving lens designed with the lens combination of Example 1. The spot size diagram is mainly used to evaluate the size and shape of the spot distribution on the image plane, reflecting the system's focusing ability on a point light source or the impact of aberrations (such as spherical aberration, coma, astigmatism, etc.). In the spot size diagram, the root mean square distance (RMS Radius) of all tracing rays to the center of the spot is controlled within 4.2 μm in the infrared band.

[0180] In summary, the optical lens in this embodiment uses aspherical lenses to correct spherical aberration and distortion, which can reduce the number of lenses required for a large image plane under a wide field of view. At the same time, the physical aperture of the five lens groups generally decreases along the optical axis, which can achieve a miniaturized lens design. In addition, the lens can effectively control the light path by combining positive and negative optical powers, achieving a larger working distance. While ensuring that the receiving lens meets the requirements of a wide field of view, it also meets the requirements of a large aperture, small size, and high resolution.

[0181] Example 4:

[0182] like Figure 13 As shown, this utility model provides a receiving lens. In this embodiment, the receiving lens includes a first lens L1 with negative optical power, an aperture stop STO, a second lens L2 with negative optical power, a third lens L3 with positive optical power, a fourth lens L4 with positive optical power, a fifth lens L5 with positive optical power, and a filter IR, arranged sequentially along the optical axis. The lens images onto the image plane IMG.

[0183] In terms of shape and structure, the first lens L1 is a meniscus aspherical lens, the second lens L2 is a meniscus spherical lens, the third lens L3 is a meniscus aspherical lens, the fourth lens L4 is a meniscus spherical lens, and the fifth lens L5 is a plano-convex spherical lens; among them, the object side and image side of the first lens L1 are both rotationally symmetric aspherical surfaces, and the object side and image side of the third lens L3 are both rotationally symmetric aspherical surfaces.

[0184] In terms of physical dimensions, the physical half-apertures of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are 6.34mm, 1.72mm, 3.2mm, 4.8mm, and 4.9mm, respectively.

[0185] In terms of optical parameters, the lens has a total effective focal length f of 2.39mm, an entrance pupil diameter of 1.9mm, a true half-image height IH corresponding to the maximum field of view of 2.31mm, and a ratio of total optical length TTL to true half-image height IH corresponding to the maximum field of view of 10.83.

[0186] Specifically, the specific parameters of each lens in the receiving lens of this embodiment and the substrate material used are shown in Table 8:

[0187] Table 8

[0188]

[0189] In Table 8, high-temperature resistant glass was selected as the substrate material for all lenses, enabling them to be used in high-temperature environments, such as automotive environments. Furthermore, considering the possibility of the first lens L1 being exposed to air, D-LAK6 material, known for its high hardness and low abrasion resistance, was chosen. Additionally, the assembly eccentricity of the fifth lens L5 is highly sensitive to performance; therefore, a single-head assembly was adopted in the design. This allows for better control of assembly eccentricity and tilt during the manufacturing process, thereby reducing process requirements, improving production yield, and ultimately reducing costs.

[0190] In this embodiment, the aspherical surfaces of the aspherical lenses (first lens L1 and third lens L3) satisfy the following aspherical formula:

[0191]

[0192] Where Z is the sag, c is the reciprocal of the radius of curvature R, y is the radial coordinate, k is the conic conic coefficient, and A2, A3, A4, A5, A6, A7, and A8 are higher-order aspherical coefficients. The specific aspherical parameters of the first lens L1 and the third lens L3 are shown in Table 9.

[0193] Table 9

[0194]

[0195] Among them, surface numbers L1S1 and L3S1 represent the object side surface of the first lens L1 and the third lens L3, respectively, and surface numbers L1S2 and L3S2 represent the image side surface of the first lens L1 and the third lens L3, respectively.

[0196] It is understood that the aspherical surfaces of each aspherical lens in the receiving lens in this embodiment can be aspherical surfaces constrained by the above-mentioned aspherical formula, or aspherical surfaces constrained by other aspherical formulas, and this application does not limit them.

[0197] Figure 14 The MTF curve of the receiving lens designed with the lens combination method of Embodiment 3 is described.

[0198] The horizontal axis represents spatial frequency (in lp / mm), and the vertical axis represents MTF value. The MTF curve can represent the lens imaging modulation at different spatial frequencies in various fields of view. Figure 14 As can be seen from the MTF curve, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view. Especially under the condition of 111 lp / mm, the MTF is greater than 30%, which indicates that the lens has good imaging resolution in both low and high frequency conditions.

[0199] Figure 15 The field curvature and distortion diagrams of the receiving lens designed with the lens combination of Embodiment 1 are shown from left to right.

[0200] Specifically, in the field curvature diagram, the horizontal axis represents the offset (in mm), and the vertical axis represents the field of view (in degrees). The S-curve represents the sagittal field curvature at a wavelength of 940 nm, and the T-curve represents the meridional field curvature at a wavelength of 940 nm. As can be seen from the field curvature diagram, the field curvature of the receiving lens in this embodiment is all within 0.08 mm, indicating that the field curvature and astigmatism of each field of view are well corrected, resulting in clear imaging at both the center and edges of the field of view.

[0201] In the distortion diagram, the horizontal axis represents the distortion value (in %), and the vertical axis represents the field of view angle (in degrees). As can be seen from the distortion diagram, the optical distortion of each field of view is within 4.8%, indicating that the image deformation caused by the main beam is small, resulting in excellent imaging quality of the system.

[0202] Figure 16 This describes the spot size diagram of the receiving lens designed with the lens combination of Example 1. The spot size diagram is mainly used to evaluate the size and shape of the spot distribution on the image plane, reflecting the system's focusing ability on a point light source or the impact of aberrations (such as spherical aberration, coma, astigmatism, etc.). In the spot size diagram, the root mean square distance (RMS Radius) of all tracing rays to the center of the spot is controlled within 4.2 μm in the infrared band.

[0203] In summary, the optical lens in this embodiment uses aspherical lenses to correct spherical aberration and distortion, which can reduce the number of lenses required for a large image plane under a wide field of view. At the same time, the physical aperture of the five lens groups generally decreases along the optical axis, which can achieve a miniaturized lens design. In addition, the lens can effectively control the light path by combining positive and negative optical powers, achieving a larger working distance. While ensuring that the receiving lens meets the requirements of a wide field of view, it also meets the requirements of a large aperture, small size, and high resolution.

[0204] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0205] The above-described embodiments are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of protection of this utility model. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the scope of protection of this utility model. Therefore, the scope of protection of this utility model should be determined by the appended claims.

Claims

1. A receiving lens, characterized in that, The receiving lens includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the optical axis. The object-side and image-side surfaces of the first lens are both rotationally symmetric aspherical surfaces, and the object-side and image-side surfaces of the fifth lens are both rotationally symmetric aspherical surfaces. The optical power of the five lenses is arranged in the following order along the direction of arrangement: negative optical power, positive optical power, negative optical power, positive optical power, and positive optical power. Alternatively, the object-side and image-side surfaces of the first lens are both rotationally symmetric aspherical surfaces, and the object-side and image-side surfaces of the third lens are both rotationally symmetric aspherical surfaces. The optical power of the five sets of lenses is, in order, negative optical power, negative optical power, positive optical power, positive optical power, and positive optical power along the arrangement direction. The base material for all five lenses is a high-temperature resistant material. The receiving lens also meets the following optical parameter conditions: 0.3 < |f1 / f2| < 1.6; 0.3 < |f2 / f3| < 2.5; 0.2 < |f3 / f4| < 2.55; 0.4 < |f4 / f5| < 1.8; 20≤TTL≤25.5; 90° <FOV<120°; Wherein, f1, f2, f3, f4, and f5 are the effective focal lengths of the first lens, the second lens, the third lens, the fourth lens, and the fifth lens, respectively; TTL is the total optical length of the receiving lens in millimeters; and FOV is the field of view of the receiving lens.

2. The receiving lens according to claim 1, characterized in that, The receiving lens also includes an aperture stop; Wherein, when the object-side surface and image-side surface of the first lens are both rotationally symmetric aspherical surfaces, and the object-side surface and image-side surface of the fifth lens are both rotationally symmetric aspherical surfaces, the aperture stop is disposed between the first lens and the second lens; when the object-side surface and image-side surface of the first lens are both rotationally symmetric aspherical surfaces, and the object-side surface and image-side surface of the third lens are both rotationally symmetric aspherical surfaces, the aperture stop is disposed between the second lens and the third lens.

3. The receiving lens according to claim 2, characterized in that, The receiving lens meets the following optical parameter conditions: 0.45 <SL / TTL<0.85; Wherein, SL is the distance from the aperture stop to the image plane of the receiving lens, in millimeters.

4. The receiving lens according to claim 1, characterized in that, The receiving lens meets the following optical parameter conditions: 0.125 <BFL / TTL<0.195; Wherein, BFL is the distance on the optical axis from the image-side surface of the fifth lens to the image-side surface of the receiving lens, in millimeters.

5. The receiving lens according to claim 1, characterized in that, The receiving lens meets the following optical parameter conditions: 13.5°≤θ≤15°; Wherein, θ is the maximum principal ray incident angle of the image plane of the receiving lens.

6. The receiving lens according to claim 1, characterized in that, The receiving lens meets the following optical parameter conditions: 2.1≤f≤3.5； Where f is the total effective focal length of the receiving lens, in millimeters.

7. The receiving lens according to claim 6, characterized in that, The receiving lens meets the following optical parameter conditions: 9≤TTL / IH≤13; Wherein, IH is the target surface half-image height of the receiving lens.

8. The receiving lens according to claim 1, characterized in that, The receiving lens meets the following optical parameter conditions: 9≤SD1≤10; 4≤SD5≤10; Wherein, SD1 is the physical aperture of the first lens, and SD5 is the physical aperture of the fifth lens, in millimeters.

9. The receiving lens according to claim 8, characterized in that, The receiving lens meets the following optical parameter conditions: 1.15≤Fno≤1.23; Wherein, Fno is the aperture size of the receiving lens.

10. The receiving lens according to any one of claims 1 to 9, characterized in that, The operating band of the receiving lens is 905nm to 950nm, and the main wavelength is 940nm.

Images