A large-aperture super-large-target DVR optical monitoring system

Abstract

This invention provides a large-aperture, ultra-large target surface DVR optical monitoring system. The optical imaging lens, along the optical axis from the object plane to the image plane, comprises: a first lens, a second lens, a third lens, a fourth lens, an aperture stop, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a filter, a protective glass, and an image plane. This invention employs a 5G4P glass-plastic hybrid optical structure, successfully increasing the system's target surface size to match a 1 / 1.2-inch large-size chip. Simultaneously, by setting an ultra-large aperture of F1.6, the system's light transmission performance is significantly enhanced, ensuring clear recording of driving conditions even in low-light environments without streetlights. Furthermore, the lens incorporates a heat-free design, maintaining focus stability over a wide temperature range of -40℃ to 85℃; and performs in-depth chromatic aberration correction, ultimately achieving high-definition imaging quality at the 8-megapixel level.

Description

Technical Field

[0001] This invention relates to the field of optical imaging technology, specifically to a large-aperture, ultra-large target surface DVR optical monitoring system. Background Technology

[0002] With the widespread adoption of intelligent driving and advanced driver assistance systems, the market has placed higher demands on the resolution and photosensitive area of ​​image sensors. Traditional DVR optical systems typically have sensor surfaces limited to 1 / 2.5 inches or smaller, with apertures usually F2.0 or smaller. When adapting to current mainstream 1 / 1.2-inch and larger sensor surface chips, traditional structures are prone to vignetting and image degradation due to insufficient image surface coverage and mismatched principal ray incident angles. Furthermore, in low-light environments such as nighttime or tunnels without streetlights, the small aperture limits light intake, reducing the image signal-to-noise ratio, increasing noise, and causing significant loss of detail. In addition, traditional lenses often use conventional materials and simple structures, resulting in insufficient thermal stability over a wide temperature range of -40℃ to 85℃. They are susceptible to thermal drift due to temperature changes, leading to back focus shift and image blur. Moreover, their ability to correct chromatic aberration is limited, and issues such as purple fringing become more pronounced as pixel counts increase to the 8-megapixel level, making it difficult to meet the demands of full-field high-definition imaging. Summary of the Invention

[0003] To address the aforementioned issues, this invention provides a large-aperture, ultra-large target surface DVR optical system to solve the problems of vignetting when adapting traditional structures to large target surface chips, imaging bottlenecks in low-light environments, insufficient stability in wide-temperature applications, and chromatic aberration correction challenges in high-pixel imaging.

[0004] This invention proposes a large-aperture, ultra-large target surface DVR optical monitoring system, which combines the characteristics of large target surface, large aperture, ultra-high-definition imaging, thermalization, and purple fringing optimization.

[0005] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a large aperture ultra-large target surface DVR optical monitoring system, which includes, in sequence along the optical axis from the object plane to the image plane: a first lens, a second lens, a third lens, a fourth lens, an aperture stop, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a filter, a protective glass, and an image plane;

[0006] The optical imaging lens comprises the following: a first lens is a meniscus lens with negative optical power; a second lens is a concave-convex lens with negative optical power; a third lens is a biconvex lens with positive optical power; a fourth lens is a biconvex lens with positive optical power; a fifth lens is a biconvex lens with positive optical power; a sixth lens and a seventh lens form a cemented lens group, wherein the sixth lens is a concave-convex lens with negative optical power, and the seventh lens is a biconvex lens with positive optical power; an eighth lens is a biconcave lens with negative optical power; and a ninth lens is a concave-convex lens with positive optical power.

[0007] The ratio of the focal length of the first to ninth lenses of the optical imaging lens to the focal length of the optical imaging lens satisfies the following set relationship:

[0008] -2.1 < f1 / f < -1.2, -2.5 < f2 / f < -1.3, 1.5 < f3 / f < 2.4, 3.8 < f4 / f < 4.9, 1.1 < f5 / f < 2.3, -6.8 < f6 / f < -5.7, 5.3 < f7 / f < 6.4, -2.6 < f8 / f < -1.6, 3.6 < f9 / f < 4.8; where f1 represents the effective focal length of the first lens, f2 represents the effective focal length of the second lens, f3 represents the effective focal length of the third lens, f4 represents the effective focal length of the fourth lens, f5 represents the effective focal length of the fifth lens, f6 represents the effective focal length of the sixth lens in the cemented lens group, f7 represents the effective focal length of the seventh lens in the cemented lens group, f8 represents the effective focal length of the eighth lens, f9 represents the effective focal length of the ninth lens, and f represents the effective focal length of the optical imaging lens.

[0009] A further embodiment is that the curvature radius R15 on the object plane side and the curvature radius R16 on the image plane side of the eighth lens of the optical imaging lens, and the curvature radius R17 on the object plane side and the curvature radius R18 on the image plane side of the ninth lens satisfy the following condition: 0.7 < (R16 + R17) / (R18 - R15) < 1.2.

[0010] A further solution is that the refractive indices of the first lens to the ninth lens satisfy the following conditions: 1.68 < n1 < 1.79; 1.57 < n2 < 1.69; 1.86 < n3 < 1.98; 1.76 < n4 < 1.88; 1.50 < n5 < 1.61; 1.83 < n6 < 1.94; 1.54 < n7 < 1.64; 1.58 < n8 < 1.68; 1.58 < n9 < 1.68; where n1 is the refractive index of the first lens, n2 is the refractive index of the second lens, n3 is the refractive index of the third lens, n4 is the refractive index of the fourth lens, n5 is the refractive index of the fifth lens, n6 is the refractive index of the sixth lens, n7 is the refractive index of the seventh lens, n8 is the refractive index of the eighth lens, and n9 is the refractive index of the ninth lens.

[0011] A further solution is that the entrance pupil diameter EPD of the optical system and the maximum image height IH of the optical system satisfy: 3 < IH / EPD < 4.

[0012] A further solution is that the chief ray angle of incidence CRA corresponding to the maximum image height of the optical system and the total optical length TTL of the optical system satisfy: 1.8 < TTL / CRA < 2.5.

[0013] A further solution is that the optical imaging lens adopts a 5G + 4P design.

[0014] A further solution is that the aperture of the optical imaging lens: F / NO = 1.6.

[0015] A further solution is that the effective focal length f of the optical imaging lens satisfies the following conditions: 5.55 mm ≤ f ≤ 6.13 mm.

[0016] A further solution is that the aperture stop ST0 of the optical imaging lens is arranged between the fourth lens E4 and the fifth lens E5.

[0017] A further embodiment is that the first lens has a convex surface facing the object side and a concave surface facing the image side; the second lens has a concave surface facing the object side and a convex surface facing the image side; the third lens has a convex surface facing both the object and image sides, and the absolute value of the radius of curvature of the object-side surface of the third lens is greater than the absolute value of the radius of curvature of the image-side surface of the third lens; the fourth lens has a convex surface facing both the object and image sides, and the absolute value of the radius of curvature of the object-side surface of the fourth lens is greater than the absolute value of the radius of curvature of the image-side surface of the fourth lens; the fifth lens has a convex surface facing the object side... The fifth lens has a convex surface on one side and a convex surface on the image side, and the absolute value of the radius of curvature of the object-side surface of the fifth lens is greater than the absolute value of the radius of curvature of the object-side surface of the fifth lens; the sixth lens has a convex surface on the object side and a concave surface on the image side; the seventh lens has a convex surface with a platform on the object side and a convex surface on the image side; the eighth lens has a concave surface on both the object and image sides, and the absolute value of the radius of curvature of the object-side surface of the eighth lens is less than the absolute value of the radius of curvature of the image-side surface of the eighth lens; the ninth lens has a convex surface on the object side and a concave surface on the image side.

[0018] In summary, this invention offers the following advantages: It employs an innovative 5G4P glass-plastic hybrid optical structure, achieving a target surface that can match a large 1 / 1.2-inch chip through precise optical power allocation and aspherical optimization. This fundamentally solves the edge vignetting problem inherent in traditional DVR lenses when adapting to large target surfaces. Simultaneously, the ultra-large F1.6 aperture significantly enhances the system's light transmission performance, ensuring clear recording of road conditions even in low-light environments without street lighting. Furthermore, the lens incorporates a heat-free design, utilizing the thermal expansion characteristics of the plastic aspherical lens to compensate for temperature drift, maintaining focus stability over a wide temperature range of -40℃ to 85℃. The use of low-dispersion materials and precision aspherical plastic lenses provides deep chromatic aberration correction, ultimately achieving 8-megapixel high-definition imaging quality and providing a complete optical solution for all-weather vehicle safety monitoring. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of an optical imaging lens provided in an embodiment of the present invention;

[0020] Figure 2 MTF analysis diagram of an optical imaging lens at 20°C in visible light, provided in an embodiment of the present invention;

[0021] Figure 3 A defocus curve of an optical imaging lens at 20°C in visible light, provided for an embodiment of the present invention;

[0022] Figure 4 The defocus curve of the optical imaging lens at -40°C in visible light is provided for an embodiment of the present invention;

[0023] Figure 5 A defocus curve of an optical imaging lens at 85°C in visible light, provided for an embodiment of the present invention;

[0024] Figure 6 The F-THETA distortion diagram of the optical imaging lens provided in the embodiment of the present invention;

[0025] Figure 7 A relative illumination diagram of an optical imaging lens provided in an embodiment of the present invention;

[0026] Figure 8 Field curvature diagram of an optical imaging lens in visible light provided for an embodiment of the present invention;

[0027] Figure 9 A standard dot plot of an optical imaging lens in visible light provided for an embodiment of the present invention.

[0028] Figure 10 The transverse chromatic aberration diagram of the optical imaging lens provided in the embodiments of the present invention at wavelengths of 435-656nm. Detailed Implementation

[0029] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0030] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0032] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] It should be noted that, in this application, the large aperture ultra-large target surface DVR optical monitoring system is a high-performance optical imaging system specifically designed for vehicle monitoring equipment such as dashcams.

[0034] like Figure 1 As shown, this invention provides a large-aperture, ultra-large target surface DVR optical monitoring system. The optical imaging lens of this system includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, an aperture stop ST0, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a ninth lens E9, an IR filter, a protective glass CG, and an image plane IMA, arranged along the object-to-image direction. Among these, the second lens E2, the fifth lens E5, the eighth lens E8, and the ninth lens E9 are plastic lenses, while the others are glass lenses.

[0035] In specific implementation, the first lens is a meniscus lens with negative optical power; the second lens is a concave-convex lens with negative optical power; the third lens is a biconvex lens with positive optical power; the fourth lens is a biconvex lens with positive optical power; the fifth lens is a biconvex lens with positive optical power; the sixth lens and the seventh lens form a cemented lens group, wherein the sixth lens is a concave-convex lens with negative optical power in the cemented lens group, and the seventh lens is a biconvex lens with positive optical power in the cemented lens group; the eighth lens is a biconcave lens with negative optical power; and the ninth lens is a concave-convex lens with positive optical power.

[0036] The ratio of the focal length of the first to ninth lenses of the optical imaging lens to the focal length of the optical imaging lens satisfies the following set relationship:

[0037] -2.1 < f1 / f < -1.2, -2.5 < f2 / f < -1.3, 1.5 < f3 / f < 2.4, 3.8 < f4 / f < 4.9, 1.1 < f5 / f < 2.3, -6.8 < f6 / f < -5.7, 5.3 < f7 / f < 6.4, -2.6 < f8 / f < -1.6, 3.6 < f9 / f < 4.8; where f1 represents the effective focal length of the first lens, f2 represents the effective focal length of the second lens, f3 represents the effective focal length of the third lens, f4 represents the effective focal length of the fourth lens, f5 represents the effective focal length of the fifth lens, f6 represents the effective focal length of the sixth lens in the cemented lens group, f7 represents the effective focal length of the seventh lens in the cemented lens group, f8 represents the effective focal length of the eighth lens, f9 represents the effective focal length of the ninth lens, and f represents the effective focal length of the optical imaging lens. By satisfying the above range and rationally allocating the optical power of each lens, spherical aberration, coma, and image plane curvature are effectively corrected, achieving aberration balance across the entire field of view. At the same time, by rationally distributing the optical power load, the problem of astigmatism and distortion exacerbated by excessive curvature of a single lens is avoided, ensuring the consistency of imaging quality between the edge field of view and the center field of view of the large target surface.

[0038] A further approach is to ensure that the curvature radii R15 on the object plane side and R16 on the image plane side of the eighth lens of the optical imaging lens, and the curvature radii R17 on the object plane side and R18 on the image plane side of the ninth lens, satisfy the following condition: 0.7 < (R16 + R17) / (R18 - R15) < 1.2. Meeting this range allows the curvature radii of the last two lenses to be coordinated: on the one hand, this causes light to gradually diverge outwards as it passes through these two lenses, effectively expanding the projection area of ​​the light beam on the image plane and forming a large imaging circle that matches the 1 / 1.2-inch chip; on the other hand, it controls off-axis aberrations and the principal ray angle, ensuring edge illumination and image sharpness. If the ratio is too small (≤0.7), the light divergence capability is insufficient, the imaging circle is difficult to cover a large target surface, dark corners are prone to appear at the edges, and the image plane is severely curved; if the ratio is too large (≥1.2), it will introduce higher-order aberrations (such as distortion and astigmatism increase sharply), and at the same time, the incident angle of the principal ray deviates from the ideal range, resulting in color crosstalk and decreased photosensitivity, and increased tolerance sensitivity, which is not conducive to mass production.

[0039] A further solution is that the refractive indices of the first lens to the ninth lens of the optical imaging lens satisfy the following conditions: 1.68 < n1 < 1.79; 1.57 < n2 < 1.69; 1.86 < n3 < 1.98; 1.76 < n4 < 1.88; 1.50 < n5 < 1.61; 1.83 < n6 < 1.94; 1.54 < n7 < 1.64; 1.58 < n8 < 1.68; 1.58 < n9 < 1.68; where n1 is the refractive index of the first lens, n2 is the refractive index of the second lens, n3 is the refractive index of the third lens, n4 is the refractive index of the fourth lens, n5 is the refractive index of the fifth lens, n6 is the refractive index of the sixth lens, n7 is the refractive index of the seventh lens, n8 is the refractive index of the eighth lens, and n9 is the refractive index of the ninth lens. By defining the above refractive index ranges, the third lens and the sixth lens have high refractive index characteristics to enhance the light converging ability, which is beneficial to the correction of spherical aberration and coma under a large aperture; the medium-high refractive index configuration of the fourth lens and the first lens is used to balance off-axis aberrations; the fifth lens and the seventh to ninth lenses adopt relatively low refractive indices to reduce the contributions of field curvature and distortion while承担必要光焦度的同时承担必要光焦度的同时承担必要光焦度的同时, ensuring the flatness of the image plane. The hierarchical matching of the refractive indices of the whole system makes the distribution of the optical power of each lens reasonable, and the aberrations are complementary between the positive and negative optical power groups, so as to achieve high-definition imaging of 8 million pixels in the full field of view on the basis of realizing a large aperture of F1.6 and adapting to a super-large target surface of 1 / 1.2 inch.

[0040] Preferably, the entrance pupil diameter EPD of the optical system and the maximum image height IH of the optical system satisfy: 3 < IH / EPD < 4. Meeting the above range enables the system to achieve a reasonable match between the entrance pupil diameter and the imaging surface size, effectively controlling off-axis aberrations and edge illumination attenuation while ensuring the light input of a large aperture of F1.6, so as to achieve the balance between large target surface imaging and low illumination performance. If the IH / EPD ratio is too large (≥4), it indicates that the entrance pupil diameter is relatively too small or the image height is too large. On the one hand, it is difficult to maintain the light passing amount required for a large aperture of F1.6, and on the other hand, the angle of the chief ray in the edge field of view increases sharply, resulting in a serious decrease in relative illumination and introducing significant image plane curvature and distortion; if the IH / EPD ratio is too small (≤3), the entrance pupil diameter is relatively too large. Although it is beneficial to low illumination imaging, it will force a significant increase in the radial size of the lens, and at the same time, the difficulty of correcting off-axis aberrations (such as coma and astigmatism) rises sharply, which is not conducive to the miniaturization of the system and the optimization of image quality. Therefore, controlling IH / EPD between 3 and 4 is the key to achieving a balance among large aperture, large target surface, miniaturization and high image quality.

[0041] Preferably, the principal ray incident angle (CRA) corresponding to the maximum image height of the optical system and the total optical length (TTL) of the optical system satisfy the following ratio: 1.8 < TTL / CRA < 2.5. Meeting this range ensures a compact structure while allowing off-axis rays to incident on the sensor surface at a near-perpendicular angle, effectively improving the relative illumination at the edges of the field of view and ensuring full-field imaging quality. If the TTL / CRA ratio is too large (≥2.5), although it is beneficial for perpendicular light incidence, it will result in a lengthy lens structure, failing to meet the miniaturization requirements of vehicle monitoring. If the TTL / CRA ratio is too small (≤1.8), the total optical length will be relatively short or the principal ray incident angle will be too large, leading to severe oblique incidence of off-axis rays. This will significantly reduce the light-sensing efficiency of the sensor's edge pixels, causing noticeable vignetting and color crosstalk, making it difficult to match the image-side telecentric requirements of large-area chips.

[0042] Preferably, the optical imaging lens adopts a 5G+4P design. Four plastic aspherical lenses and five glass lenses form a thermally complementary structure, effectively compensating for focal plane drift over a wide temperature range and achieving athermal stable imaging from -40℃ to 85℃. Simultaneously, by combining the aspherical degrees of freedom of the low-dispersion glass material and the plastic aspherical lenses, positional and magnification chromatic aberrations in the visible light band are deeply corrected, significantly suppressing purple fringing and enabling the full-field imaging quality to meet the 8-megapixel requirement, satisfying the stringent chromatic aberration correction requirements of large-area chips.

[0043] Preferably, in the optical imaging lens provided in the embodiments of the present invention, the aperture of the optical imaging lens is F / NO = 1.6. The present invention sets the F-number of the optical system to F / NO = 1.6, enabling the system to possess ultra-large aperture characteristics, ensuring sufficient light intake even in low-light environments such as those without streetlights, and achieving clear low-light imaging in conjunction with a large-area chip. If the F-number is too large (>1.6), the light intake is insufficient, resulting in increased noise and loss of detail in nighttime images, failing to meet the needs of driving safety monitoring; if the F-number is too small (<1.6), although the light intake is greater, it significantly increases the difficulty of correcting spherical aberration, coma, and higher-order aberrations, leading to a decrease in full-field resolution.

[0044] Preferably, in the optical imaging lens provided in the embodiments of the present invention, the effective focal length f of the optical imaging lens satisfies the following condition: 5.55mm ≤ f ≤ 6.13mm. The reason for this setting is that if the focal length is too short, it will cause a sharp increase in edge aberrations and vignetting; if the focal length is too long, it will affect the monitoring range and is not conducive to a compact structure. This range ensures a reasonable field of view and imaging quality when adapting to a 1 / 1.2-inch large target surface.

[0045] Preferably, in the optical imaging lens provided in the embodiments of the present invention, the aperture ST0 of the optical imaging lens is disposed between the fourth lens E4 and the fifth lens E5.

[0046] Preferably, the first lens has a convex surface facing the object side and a concave surface facing the image side; the second lens has a concave surface facing the object side and a convex surface facing the image side; the third lens has a convex surface facing both the object and image sides, and the absolute value of the radius of curvature of the object-side surface of the third lens is greater than the absolute value of the radius of curvature of the image-side surface of the third lens; the fourth lens has a convex surface facing both the object and image sides, and the absolute value of the radius of curvature of the object-side surface of the fourth lens is greater than the absolute value of the radius of curvature of the image-side surface of the fourth lens; the fifth lens has a convex surface facing the object side... The fifth lens has a convex surface, with the image-side side being convex, and the absolute value of the radius of curvature of the object-side side of the fifth lens is greater than the absolute value of the radius of curvature of the image-side side of the fifth lens; the sixth lens has a convex surface facing the object side and a concave surface facing the image side; the seventh lens has a convex surface with a platform facing the object side and a convex surface facing the image side; the eighth lens has a concave surface facing the object side and a concave surface facing the image side, and the absolute value of the radius of curvature of the object-side side of the eighth lens is less than the absolute value of the radius of curvature of the image-side side of the eighth lens; the ninth lens has a convex surface facing the object side and a concave surface facing the image side.

[0047] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

[0048] The parameters of each lens in this embodiment are listed in Table 1 below, and the aspherical coefficients of the lenses are shown in Table 2 below.

[0049] Table 1 Physical parameters of each lens

[0050]

[0051] Table 2 Aspherical coefficients of lenses

[0052] SURFACE:3 K=-1.45207938022 a4=0.000385277632622 a6=-0.00004533220682648 a8=0.0000001388546474312 a10=-1.504964103263E-08 a12 = 3.453969807738E-10 R1=-6.313183776 SURFACE:4 K=-200 a4=0.0004465567351899 a6=-0.0000453919594285 a8=0.0000004582104414987 a10=-4.553581338251E-08 a12 = 9.448239189255E-10 R2=-85.27002776 SURFACE:10 K=3.153987873929 a4=-0.0003521299209446 a6=-0.00001423368840162 a8=0.0000006824211504201 a10=-6.043826214019E-08 a12 = -8.225258103924E-10 a14 = 1.853566247944E-10 a16=-0.0000000000076584512 R1=13.86029943 SURFACE:11 K=5.8232086965398 a4=0.0003758179653059 a6=-0.00000875708091657 a8=0.0000002462542142675 a10=-1.048242339776E-08 a12=-1.724749400666E-09 a14 = 1.275788031086E-10 a16 = -2.76207916189E-12 R2=-9.432103063 SURFACE:15 K=-10.76861891427 a4=0.003356342712565 a6=-0.0001059454800513 a8=0.0000004823054875233 a10=0.0000004461077362387 a12=-1.458203298765E-08 a14 = 3.762993816903E-10 a16 = -4.77381444532E-12 R1=-11.21325614 SURFACE:16 K=-160.4428412912 a4=0.003384706150085 a6=-0.00007754356785828 a8=0.000004381802986055 a10=-3.347914674178E-08 a12=-0.0000000063887968568 a14 = 2.443482352627E-10 a16 = -3.485770533576E-12 R2=26.3257013 SURFACE:17 K=-14.37530938527 a4=-0.0008530012575102 a6=0.00006353614575506 a8=0.0000003483888871464 a10=8.445404341815E-09 a12 = -4.468239208285E-10 a14 = 3.732921317012E-12 R1=10.82883207 SURFACE:18 K=-74.75146683648 a4=-0.004461117625116 a6=0.00000732898171675 a8=0.0000004687491823708 a10=-2.438774495236E-08 a12=5.683477601808E-10 a14 = -6.843936983462E-12 R2=23.87722167

[0053] The aspherical coefficients satisfy the following equation:

[0054]

[0055] Where z is the aspherical sagitta, c is the paraxial curvature of the aspherical surface, y is the lens aperture, k is the conic coefficient, a4 is the 4th order aspherical coefficient, a6 is the 6th order aspherical coefficient, a8 is the 8th order aspherical coefficient, a10 is the 10th order aspherical coefficient, a12 is the 12th order aspherical coefficient, a14 is the 14th order aspherical coefficient, and a16 is the 16th order aspherical coefficient.

[0056] Specifically, in this embodiment, the R-value (radius of curvature), thickness, refractive index (Nd), and Abbe coefficient (Vd) of each lens surface are shown in Table 1, and the aspherical parameters are shown in Table 2. In Table 1, Surf represents the mirror number, and InFInITY represents infinity. In Table 2, R1 represents the radius of curvature of the corresponding lens surface facing the object side, and R2 represents the radius of curvature of the corresponding lens surface facing the image side. A positive radius of curvature indicates that the mirror is curved towards the object side, and a negative radius of curvature indicates that the mirror is curved towards the image side.

[0057] Among them, the optical imaging lens provided in Table 1 has an effective focal length of 5.84mm, a maximum holographic height of 12.78mm, and an aperture of F / N1.6. In Table 1, mirror numbers 1 and 2 represent the two mirrors of the first lens E1 along the direction of light incidence, mirror numbers 3 and 4 represent the two mirrors of the second lens E2 along the direction of light incidence, mirror numbers 5 and 6 represent the two mirrors of the third lens E3 along the direction of light incidence, mirror numbers 7 and 8 represent the two mirrors of the fourth lens E4 along the direction of light incidence, mirror numbers 10 and 11 represent the two mirrors of the fifth lens E5 along the direction of light incidence, mirror number 12 represents the object-side mirror of the sixth lens E6, mirror number 13 represents the cemented surface of the sixth lens E6 and the seventh lens E7, mirror number 14 represents the image-side mirror of the seventh lens E7, mirror numbers 15 and 16 represent the two mirrors of the eighth lens E8 along the direction of light incidence, and mirror numbers 17 and 18 represent the two mirrors of the ninth lens E9 along the direction of light incidence.

[0058] In an embodiment of the present invention, Figure 2 This is a modulation transfer function (MTF) curve for the visible light band, representing the overall resolving power of an optical system. The horizontal axis represents spatial frequency, in cycles per millimeter (mm), and the vertical axis represents the MTF value. The MTF value is used to evaluate the image quality of a lens, ranging from 0 to 1. It is worth noting that the optical transfer function is a relatively accurate, intuitive, and common way to evaluate the image quality of an optical system. The higher and smoother the curve, the better the image quality and the stronger the ability to reproduce the true image. Figure 2 It can be seen that in the visible light band, the MTF in the imaging region near the center is >0.7, indicating good imaging quality. Figure 3 The defocus curve shows that the lens has good MTF concentration, making focusing easy. From... Figure 4 and Figure 5 It can be seen that the defocus curves at both high and low temperatures meet the requirements of high resolution, with small changes in focus, and no blurring in focus under both high and low temperature environments; Figure 6 This is represented as an F-THETA distortion map. The smaller the F-THETA distortion, the less the compression at the edges of the image. Figure 7 Represented as a relative illumination diagram, higher relative illumination indicates higher overall brightness of the captured image; by Figure 8 It can be seen that the field curvature value should be controlled between -0.045mm and 0.045mm. The smaller the field curvature value, the better the image quality of the lens. Figure 9 This is a standard dot plot of visible light wavelengths according to an embodiment of the invention; Figure 10 Represented as a vertical axis chromatic aberration diagram, the smaller the vertical axis chromatic aberration, the better the color reproduction of the image and the better the purple fringing optimization.

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