A lens system

Abstract

This invention discloses a lens system comprising a first lens, a second lens, an aperture stop, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially along the optical axis from the object plane to the image plane. The first, third, fourth, and fifth lenses are glass spherical lenses, while the second, sixth, seventh, and eighth lenses are plastic aspherical lenses. The optical powers of the first to eighth lenses are negative, negative, positive, positive, negative, positive, negative, negative, and negative, respectively. The object-side surface of the first lens is convex, and the image-side surface is concave; the object-side surface of the second lens is concave, and the image-side surface is convex; the object-side surface of the third lens is convex; both the object-side and image-side surfaces of the fourth lens are convex; both the object-side and image-side surfaces of the fifth lens are concave; and both the object-side and image-side surfaces of the sixth lens are convex. This system offers advantages such as a wide-angle lens, a large image surface, compact design, and day / night confocal ultra-high-definition imaging.

Description

Technical Field

[0001] The present invention relates to the field of optical device technology, and in particular to a lens system. Background Technology

[0002] With the continuous advancement of the security monitoring industry, society is placing increasingly higher demands on security. Compact ultra-high-definition lens systems with wide field of view, large image area, and day / night confocal focus are becoming increasingly popular in the security market. Existing wide-angle lenses generally have a small image area, while wide-angle lenses with large image areas generally suffer from excessive overall length and low relative illumination. Summary of the Invention

[0003] In view of this, the present invention provides a lens system that uses four standard glass spherical lenses and four non-curved plastic lenses to achieve a field of view of 180°, an imaging target surface of 10.0 mm, a total length of less than 20.0 mm, and high relative illumination for day and night confocal ultra-high-definition imaging.

[0004] This application provides a lens system including a first lens, a second lens, an aperture stop, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially along the optical axis from the object plane to the image plane; along the optical axis from the object plane to the image plane,

[0005] The first lens is a glass spherical lens with negative optical power, a convex object-side surface, and a concave image-side surface; the second lens is a plastic aspherical lens with negative optical power, a concave object-side surface, and a convex image-side surface; the third lens is a glass spherical lens with positive optical power and a convex object-side surface; the fourth lens is a glass spherical lens with positive optical power and both its object-side and image-side surfaces are convex; the fifth lens is a glass spherical lens with negative optical power and both its object-side and image-side surfaces are concave; the sixth lens is a plastic aspherical lens with positive optical power and both its object-side and image-side surfaces are convex; the seventh lens is a plastic aspherical lens with negative optical power; and the eighth lens is a plastic aspherical lens with negative optical power.

[0006] As a preferred embodiment, the first lens and the second lens form a first lens group, and the first lens group satisfies the following relationship:

[0007] in, The combined optical power of the first lens group. The optical power of the lens system is denoted as .

[0008] As a preferred embodiment, the third lens, the fourth lens, and the fifth lens constitute a second lens group, and the second lens group satisfies the following relationship:

[0009] in, The combined optical power of the second lens group is [missing information]. The optical power of the lens system is denoted as .

[0010] As a preferred embodiment, the sixth lens, the seventh lens, and the eighth lens constitute a third lens group, and the third lens group satisfies the following relationship:

[0011] in, The combined optical power of the third lens group. The optical power of the lens system is denoted as .

[0012] As a preferred embodiment, the optical power of the lens system satisfies the following relationship:

[0013]

[0014] in, This indicates the optical power of the first lens. This indicates the optical power of the second lens; This indicates the optical power of the third lens; This indicates the optical power of the sixth lens; This indicates the optical power of the seventh lens; This indicates the optical power of the eighth lens; This indicates the optical power of the lens system.

[0015] As a preferred embodiment, the fourth lens and the fifth lens are cemented together to form a cemented lens group, and the optical power of the cemented lens group is... Optical power of the lens system The following relationship must be satisfied:

[0016]

[0017] As a preferred embodiment, the lens system satisfies the following relationship: 1.025 ≤ D1 / (F no *Y max ≤1.075;

[0018] Where D1 represents the maximum effective diameter of the first lens, F no Y represents the aperture of the lens system. max This represents the maximum image circle radius of the lens system.

[0019] As a preferred embodiment, the sagitta Sag7 of the object-side surface of the seventh lens and the half-aperture d7 of the object-side surface of the seventh lens satisfy: -0.265≤Sag7 / d7≤-0.215;

[0020] The full-aperture sagitta Sag7 of the image-side surface of the seventh lens A The half-aperture sagitta Sag7 of the image-side surface of the seventh lens B Satisfies: 0.185≤Sag7 B / Sag7 A ≤0.325.

[0021] As a preferred embodiment, the sag8 of the image-side surface of the eighth lens and the half-aperture d8 of the image-side surface of the eighth lens satisfy: -0.095≤Sag8 / d8≤-0.045;

[0022] The full-aperture sagitta Sag8 of the object-side surface of the eighth lens A The half-aperture sagitta Sag8 of the object side surface of the eighth lens B Satisfies: -0.028 ≤ Sag8 B / Sag8 A ≤-0.008.

[0023] As a preferred embodiment, the lens system also includes a flat glass plate disposed in the optical path between the eighth lens and the image plane.

[0024] In summary, the lens system provided in this application consists of four standard glass spherical lenses and four standard glass spherical lenses. The number of lenses is reasonable, the structure is simple and compact, and the optical power and position of each lens element are reasonable. It can achieve day and night confocal imaging and high resolution, and achieves a field of view of 180°, an imaging target area of ​​10.0 mm, a total length of less than 20.0 mm, and high relative illumination for day and night confocal ultra-high-definition imaging. This wide-angle, large target area, and compact lens system has greater competitiveness in the market. Attached Figure Description

[0025] Figure 1 Here is a schematic diagram of a lens system provided in Embodiment 1 of this application:

[0026] Figure 2 An axial aberration curve of a lens system provided in Embodiment 1 of this application:

[0027] Figure 3 A ray fan pattern for a lens system provided in Embodiment 1 of this application:

[0028] Figure 4 A field curvature distortion curve of a lens system provided in Embodiment 1 of this application:

[0029] Figure 5 A relative illumination diagram of a lens system provided in Embodiment 1 of this application:

[0030] Figure 6Here is a schematic diagram of a lens system provided in Embodiment 2 of this application:

[0031] Figure 7 A spherical aberration curve for a lens system provided in Embodiment 2 of this application:

[0032] Figure 8 A ray fan pattern for a lens system provided in Embodiment 2 of this application:

[0033] Figure 9 Here is a field curvature distortion curve of a lens system provided in Embodiment 2 of this application:

[0034] Figure 10 A relative illumination diagram of a lens system provided in Embodiment 2 of this application:

[0035] Figure 11 Here is a schematic diagram of a lens system provided in Embodiment 3 of this application:

[0036] Figure 12 A spherical aberration curve for a lens system provided in Embodiment 3 of this application:

[0037] Figure 13 A ray fan pattern for a lens system provided in Embodiment 3 of this application:

[0038] Figure 14 Here is a field curvature distortion curve of a lens system provided in Embodiment 3 of this application:

[0039] Figure 15 This is a relative illumination diagram of a lens system provided in Embodiment 3 of this application. Detailed Implementation

[0040] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present application are shown in the drawings, not the entire structure.

[0041] Figure 1 This is a schematic diagram of a lens system provided in Embodiment 1 of this application. Figure 1 As shown, the lens system 100 provided in this application embodiment includes a first lens L1, a second lens L2, an aperture stop, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8 arranged sequentially along the optical axis from the object plane to the image plane.

[0042] Along the optical axis from the object plane to the image plane: Lens L1 is a glass spherical lens with negative optical power. Its object-side surface is convex, and its image-side surface is concave. Lens L2 is a plastic aspherical lens with negative optical power. Its object-side surface is concave, and its image-side surface is convex. Lens L3 is a glass spherical lens with positive optical power. Its object-side surface is convex, and the shape of its image-side surface is not limited. Lens L4 is a glass spherical lens with positive optical power. Both its object-side and image-side surfaces are convex. Lens L5 is a glass spherical lens with negative optical power. Both its object-side and image-side surfaces are concave. Lens L6, the sixth lens, is a plastic aspherical lens with positive optical power. Both its object-side and image-side surfaces are convex. Lens L7, the seventh lens, is also a plastic aspherical lens with negative optical power. The shape of its object-side and image-side surfaces is not specified. Lens L8, the eighth lens, is also a plastic aspherical lens with negative optical power.

[0043] Optical power is equal to the difference between the convergence of light beams at the image plane and the convergence of light beams at the image plane. It characterizes the ability of a lens system to deflect light. The larger the absolute value of optical power, the stronger the ability to bend light; the smaller the absolute value of optical power, the weaker the ability to bend light. When optical power is positive, the refraction of light is converging; when optical power is negative, the refraction of light is diverging. Optical power can be used to characterize a single refractive surface of a lens (i.e., one surface of the lens), a single lens, or a system formed by multiple lenses (i.e., a lens group).

[0044] For example, refer to Figure 1 As shown, along the optical axis from the object plane to the image plane, the optical power combination of the eight lenses in this application is as follows: the first lens L1 has negative optical power, the second lens L2 has negative optical power, the third lens L3 has positive optical power, the fourth lens L4 has positive optical power, the fifth lens L5 has negative optical power, the sixth lens L6 has positive optical power, the seventh lens L7 has negative optical power, and the eighth lens L8 has negative optical power.

[0045] In the embodiments of this application, reference is made to Figure 1 As shown, the first lens L1 is designed as a meniscus negative lens with its convex surface facing the object side, which can converge light rays with a large field of view into the system as much as possible, thus improving the field of view of the optical system. For example, the field of view of this lens system is 180°.

[0046] Optionally, the optical power of the first lens L1 can be set. and the optical power of the lens system The following relationship must be satisfied:

[0047] in, This indicates the optical power of the first lens L1. This indicates the optical power of the lens system at 100.

[0048] This configuration allows the eighth lens L8 to converge incident light rays, control the optical path of the entire optical system, and reduce its size.

[0049] In this embodiment, the second lens L2 is designed as a concave-convex negative lens, which can effectively control the direction of light, reduce field curvature and spherical aberration of the optical system, and improve the image quality of the optical system.

[0050] Optionally, the optical power of the second lens L2 can be set. and the optical power of the lens system The following relationship must be satisfied: in, This indicates the optical power of the second lens L2.

[0051] In this embodiment, the object-side surface of the third lens L3 is designed to be convex and has positive optical power, which can effectively control the light to enter the rear of the optical system smoothly, reduce the spherical aberration of the optical system, and improve the imaging quality of the optical system.

[0052] Optionally, the optical power of the third lens can be set. and the optical power of the lens system The following relationship must be satisfied:

[0053] By placing the aperture stop STO between the second lens L2 and the third lens L3, and near the image side of the second lens L2, this application can reduce the generation of astigmatism in the lens system, and is conducive to gathering the light entering the lens system, reducing the rear aperture of the lens system, and improving the image quality of the lens.

[0054] Among them, the aperture stop STO includes the aperture stop and the field stop. The aperture stop refers to the stop that restricts the beam the most, and the field stop refers to the stop that restricts the field of view (size) the most.

[0055] In this embodiment, the fourth lens L4 has convex surfaces on both the object-side and image-side faces. The fifth lens L5 has concave surfaces on both the object-side and image-side faces.

[0056] Optionally, a cemented lens group with negative optical power can be formed by setting a fourth lens L4 and a fifth lens L5. With a lens system of 100 optical power The following relationship must be satisfied:

[0057] Specifically, both the fourth lens L4 and the fifth lens L5 are glass spherical lenses. Cemented glass lenses effectively reduce spherical aberration, coma, astigmatism, field curvature, positional chromatic aberration, and magnification chromatic aberration in the entire lens system, improving the final image quality and chromatic aberration correction. Furthermore, the first lens L1, third lens L3, and fifth lens L5 all employ glass spherical lenses with low-dispersion materials, optimizing the purple fringing effect at object edges and better reproducing the true image. This also provides thermal compensation for the entire optical system, ensuring stable thermal drift at high and low temperatures and guaranteeing the required resolution at these conditions. Additionally, it smooths out light transitions, reduces the tolerance sensitivity of the optical system, and improves the assembly yield.

[0058] In this embodiment, the sixth lens L6 is a biconvex plastic aspherical positive lens, and the seventh lens L7 and the eighth lens L8 are both plastic aspherical lenses. The sixth lens L6 can effectively control the direction of light, converge the light, and shorten the overall optical length of the system, making the system structure more compact. The object-side surface of the seventh lens L7 can be concave, which can effectively control the direction of light, allowing the light to enter the eighth lens L8 with a smaller deflection angle, thus effectively reducing the system's tolerance sensitivity. The eighth lens L8 can effectively control the direction of light, raise the light beam height, and achieve the design effect of large target surface imaging.

[0059] Optional, the optical power of the sixth lens L6 Optical power of the lens system The following relationship must be satisfied: Optical power of the seventh lens L7 Optical power of the lens system The following relationship must be satisfied: The optical power of the eighth lens L8 Optical power of the lens system The following relationship must be satisfied:

[0060] In summary, this application, through the combination of the optical power of the above-mentioned eight lenses and the reasonable matching of their surface shapes, can effectively save space and expand the application scenarios of the lens.

[0061] Based on the above embodiments, the first lens L1 to the eighth lens L8 can be divided into three groups, and the combined optical power of each group of lenses can be controlled to improve the imaging effect of the lens system.

[0062] Optionally, the first lens L1 and the second lens L2 are configured to form a first lens group A, which satisfies the following relationship:

[0063] in, The combined optical power of the first lens group A, The optical power of the lens system is 100.

[0064] Optionally, the third lens L3, the fourth lens L4, and the fifth lens L5 are configured to form a second lens group B, which satisfies the following relationship:

[0065] in, The combined optical power of the second lens group B. The optical power of the lens system is 100.

[0066] Optionally, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are configured to form a third lens group C, which satisfies the following relationship:

[0067] in, The combined optical power of the third lens group C, The optical power of the lens system is 100.

[0068] This application groups eight lenses into a first lens group A, a second lens group B, and a third lens group C, so that the optical power of the three lens groups has a reasonable distribution ratio. While achieving a wide angle and a large target surface, it can make the light transition between different lens groups with a small deflection angle, effectively controlling the introduction of system aberrations and facilitating the realization of ultra-high-definition imaging effect of the lens system.

[0069] Based on the above embodiments, the lens system 100 can be further defined to satisfy the following relationship: 1.025≤D1 / (Fno*Y) max )≤1.075.

[0070] Where D1 represents the maximum effective diameter of the first lens L1, Fno represents the aperture of the lens system 100, and Y max This indicates the maximum image circle radius of lens system 100.

[0071] By limiting the maximum image circle and aperture size of the optical imaging system, this application can achieve the purpose of limiting the effective optical diameter of the first lens L1, thereby ensuring the miniaturization of the optical system.

[0072] Based on the above embodiments, the sagitta Sag7 of the object-side surface of the seventh lens L7 and the half-aperture d7 of the object-side surface of the seventh lens L7 are defined to satisfy: -0.265≤Sag7 / d7≤-0.215, and the full-aperture sagitta Sag7 of the image-side surface of the seventh lens L7 is defined as follows: A The half-aperture sagitta Sag7 of the image side of the seventh lens L7 B Satisfies: 0.185≤Sag7 B / Sag7 A ≤0.325.

[0073] Based on the above embodiments, the image-side elevation Sag8 of the eighth lens L8 and the half-aperture d8 of the image-side surface of the eighth lens L8 are defined to satisfy: -0.095≤Sag8 / d8≤-0.045, and the full-aperture elevation Sag8 of the object-side surface of the eighth lens L8 is defined. A The half-aperture sagitta Sag8 of the object side surface of the eighth lens L8 B satisfy:

[0074] -0.028≤Sag8 B / Sag8 A ≤-0.008.

[0075] This application can effectively raise the height of light by controlling the shape of the seventh lens L7 and the eighth lens L8, thereby achieving the design effect of large target surface imaging. At the same time, controlling the shape of the lenses can allow light from a large field of view to enter the image plane at a reasonable angle, thus ensuring the design requirement that the relative illumination of the system is not less than 40%.

[0076] Reference Figure 1 As shown, each lens of the lens system provided in this application embodiment can be fixed inside a lens barrel and sealed or vacuum-sealed. The fixed setting can ensure the stability and clarity of each lens surface and ensure image quality. This application embodiment will not show them one by one.

[0077] Optional, refer to Figure 1 As shown, the lens system 100 may further include a flat glass CG disposed in the optical path between the eighth lens L8 and the image plane. The flat glass CG can protect the photosensitive chip in the imaging sensor. The imaging chip is used to convert the light signals collected by the lens system into electrical signals, thereby ensuring the imaging effect of the lens system.

[0078] The following are some specific embodiments to illustrate the optical performance parameters of the lens system provided in this application.

[0079] As one possible implementation method, please refer to [reference]. Figure 1 The lens system 100 provided in Embodiment 1 has a focal length f of 3.54mm, an aperture of F# of 2.00, and a field of view D. FOV =180°, total optical length TTL: 19.99mm. Table 1 shows the optical physical parameters of the first lens L1 to the eighth lens L8 in the lens system 100 provided in Embodiment 1 of this application. The units for radius of curvature R and thickness d are millimeters (mm). Table 2 shows the aspherical coefficient values ​​of the aspherical lenses in the lens system 100 provided in Embodiment 1 of this application.

[0080] Table 1 Design values ​​of optical physical parameters for the lens system

[0081] Face number Surface type Radius of curvature (mm) Thickness (mm) (nd) / (vd) Half-diameter (mm) k value S1 Standard surface 11.507 0.701 1.816 / 46.57 5.25 S2 Standard surface 2.969 3.304 2.85 S3 even aspherical surface -3.474 1.825 1.535 / 55.71 2.46 -0.448 S4 even aspherical surface -7.746 0.273 2.01 -11.732 S5 STO INF -0.200 2.00 S6 Standard surface 5.474 1.528 1.762 / 26.61 2.07 S7 Standard surface -140.815 0.846 2.08 S8 Standard surface 5.638 2.055 1.593 / 68.62 2.10 S9 Standard surface -3.317 0.705 1.741 / 27.76 2.24 S10 Standard surface 8.705 0.052 2.60 S11 even aspherical surface 9.952 1.957 1.535 / 55.71 2.68 10.531 S12 even aspherical surface -2.860 0.024 2.82 -4.953 S13 even aspherical surface -30.834 0.868 1.640 / 23.50 2.84 -90.998 S14 even aspherical surface 17.868 0.190 3.28 -82.431 S15 even aspherical surface -10.173 1.718 1.535 / 55.71 4.08 -114.213 S16 even aspherical surface -18.881 2.420 4.32 -75.692 S17 Standard surface INF 0.710 1.517 / 64.21 4.78 S18 Standard surface INF 0.915 4.85 IMA Standard surface INF 5.00

[0082] In Table 1, the surface numbers are assigned according to the surface sequence of each lens. For example, surfaces S1 and S2 are the object-side and image-side surfaces of the first lens L1, respectively; surfaces S3 and S4 are the object-side and image-side surfaces of the second lens L2, respectively, and so on. "STO" represents the aperture stop of the lens. The radius of curvature represents the degree of curvature of the corresponding lens surface. A positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. "INF" indicates that the surface is flat and the radius of curvature is infinite. "IMA" represents the image plane. The thickness represents the central axial distance between the current surface and the next surface. The refractive index nd represents the ability of the material between the current surface and the next surface to deflect light. A blank space indicates that the current position is air and the refractive index is 1. The Abbe number vd is an index used to represent the dispersion ability of a transparent medium. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less severe the dispersion of the medium, the larger the Abbe number.

[0083] In this first embodiment, the second lens L2, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are aspherical lenses, with both their object-side and image-side surfaces being aspherical. Their aspherical surface shape equation Z satisfies:

[0084] In Embodiment 1 of this application, the aspherical lens of the lens system 100 satisfies the following formula:

[0085]

[0086] Where z is the axial sagitta in the Z-direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the fitted conic coefficient; A, B, C, D, E, F, and G are the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order aspherical coefficients corresponding to the aspherical surface; and the units of Z, r, and c are all mm.

[0087] Table 2 Aspherical coefficients of the lens system

[0088] Face number A B C D E F G S3 7.481311E-03 -3.296447E-04 1.567802E-05 -1.316868E-06 6.031244E-07 -9.898616E-08 5.314455E-09 S4 1.128078E-03 2.690498E-04 -1.104416E-04 1.950709E-05 -7.877062E-07 -3.111387E-07 4.550972E-08 S11 2.293737E-04 -5.030650E-05 1.980716E-05 -7.885636E-06 4.878228E-08 1.648716E-07 -1.669877E-08 S12 -1.328929E-03 4.999969E-04 3.927763E-05 -8.773292E-06 -5.678046E-07 4.281693E-08 5.358747E-09 S13 -1.583397E-02 6.364391E-04 1.086393E-04 6.518202E-06 -4.603130E-06 2.731837E-07 5.471442E-09 S14 -1.884887E-02 2.797005E-03 -1.796369E-04 6.132076E-06 1.864534E-07 -4.216102E-08 1.769235E-09 S15 7.678135E-03 -3.718484E-04 3.031577E-06 4.096024E-07 -1.086776E-09 -1.148544E-09 2.404097E-11 S16 4.423762E-03 -5.874545E-04 2.316651E-05 2.504871E-07 -3.196205E-08 1.596417E-10 3.521851E-12

[0089] In Table 2, 7.481311E-03 indicates that the coefficient A for surface number S3 is 7.481311*10. -3 And so on.

[0090] Furthermore, several performance tests were conducted on the lens system 100 provided in Embodiment 1, and the specific test results are as follows:

[0091] Figure 2This is an axial aberration curve diagram of a lens system provided in Embodiment 1 of this application. Figure 2 As shown, the vertical direction represents the normalized aperture, with 0 indicating the optical axis, and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the figure represent different wavelengths of system imaging, determined by... Figure 2 It can be seen that the axial aberrations of the normalized apertures of different wavelengths from 0 to 1.0 are all controlled within the range of (-0.05 mm, +0.05 mm), indicating that the lens system 100 provided in Embodiment 1 of this application has achieved good control of spherical aberration at each wavelength, which can meet the requirements of wide spectrum applications.

[0092] Figure 3 This document presents a ray fan diagram of a lens system according to Embodiment 1 of this application. Ray fan diagrams are a commonly used evaluation method by optical designers. For example... Figure 3 As shown, in a single image, the horizontal axis represents the normalized beam aperture, and the vertical axis represents the transverse aberration. Ideally, each curve should perfectly coincide with the horizontal axis, in which case all rays in that field of view focus at the same point on the image plane; the vertical axis in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The fan plot can not only reflect monochromatic aberrations of different wavelengths but also the magnitude of transverse chromatic aberration. Figure 3 It can be seen that the system closely approximates the horizontal axis at each wavelength in each field of view, indicating that the transverse aberration of each wavelength is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the chromatic aberration of the system is also well corrected, thus ensuring that the optical system can achieve the high-resolution imaging requirements.

[0093] Figure 4 This is a field curvature distortion diagram of a lens system provided in Embodiment 1 of this application, such as... Figure 4 As shown, in the coordinate system on the left, the horizontal axis represents the field curvature of the lens system, in mm; the vertical axis represents the normalized image height, without units. In the coordinate system on the right, the horizontal axis represents the distortion (F-Tan(Theta)), in %; the vertical axis represents the normalized image height, without units. Figure 4 As can be seen, the lens system provided in this embodiment effectively controls the field curvature of light from wavelengths of 436nm to 850nm, meaning that during imaging, the difference in image quality between the center and the periphery is small. Simultaneously, the distortion of the lens system is well corrected, resulting in minimal imaging distortion.

[0094] Figure 5 The relative illumination diagram of a lens system provided in Embodiment 1 of this application is provided. The relative illumination refers to the ratio of the illumination at different coordinate points on the image plane to the illumination at the center point, that is, the ratio of the illumination at other fields of view to the illumination at the center field of view. It is an important evaluation index of imaging optical systems. Figure 5 In this diagram, the vertical axis represents relative illumination, and the horizontal axis represents the field of view angle. In an imaging optical system, if the relative illumination of a certain field of view is low, vignetting is likely to occur. Figure 5 It can be seen that the relative illumination of this lens system is greater than 40%, which meets the requirements of common lens systems for this indicator, and the vignetting control performance is good.

[0095] In summary, the lens system provided in Embodiment 1 of this application consists of four standard glass spherical elements and four non-curved plastic lenses. The number of lenses is reasonable, the structure is simple and compact, and the optical power and position of each lens element are reasonable, which can achieve day and night confocality and high resolution. At the same time, the wide-angle, large-area compact lens system has greater competitiveness in the market.

[0096] Example 2

[0097] Figure 6 This is a schematic diagram of a lens system provided in Embodiment 2 of this application. Figure 6 As shown, the lens system 100 provided in Embodiment 2 of this application includes a first lens L1, a second lens L2, an aperture stop, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8 arranged sequentially along the optical axis from the object plane to the image plane. Along the optical axis from the object plane to the image plane...

[0098] The first lens L1 is a glass spherical lens with negative optical power, a convex object-side surface, and a concave image-side surface; the second lens L2 is a plastic aspherical lens with negative optical power, a concave object-side surface, and a convex image-side surface; the third lens L3 is a glass spherical lens with positive optical power, and its object-side surface is convex; the fourth lens L4 is a glass spherical lens with positive optical power, and both its object-side and image-side surfaces are convex; the fifth lens L5 is a glass spherical lens with negative optical power, and both its object-side and image-side surfaces are concave; the sixth lens L6 is a plastic aspherical lens with positive optical power, and both its object-side and image-side surfaces are convex; the seventh lens L7 is a plastic aspherical lens with negative optical power; and the eighth lens L8 is a plastic aspherical lens with negative optical power.

[0099] A flat glass CG is positioned in the optical path between the eighth lens L8 and the image plane. The flat glass CG protects the photosensitive chip in the imaging sensor. The imaging chip converts the light signals collected by the lens system into electrical signals, thereby ensuring the imaging effect of the lens system.

[0100] As one possible implementation method, please refer to [reference]. Figure 6 The lens system 100 provided in Embodiment 2 of this application has a focal length f of 3.525mm, an aperture of F# of 2.00, and a field of view D. FOV=180°, total optical length TTL: 19.96mm. Table 3 shows the optical physical parameters of the first lens 21 to the fifth lens 25 in the lens system 100 provided in Embodiment 2 of this application. The units for radius of curvature R and thickness d are millimeters (mm). Table 4 shows the aspherical coefficient values ​​of the aspherical lenses in the lens system 100 provided in Embodiment 2 of this application.

[0101] Table 3 Design values ​​of optical physical parameters for the lens system

[0102] Face number Surface type Radius of curvature (mm) Thickness (mm) (nd) / (vd) Half-diameter (mm) k value S1 Standard surface 12.660 0.701 1.816 / 46.57 5.24 S2 Standard surface 3.140 3.232 2.95 S3 even aspherical surface -3.333 1.731 1.535 / 55.71 2.64 -0.461 S4 even aspherical surface -7.224 0.287 2.20 -10.683 S5 STO INF -0.200 2.00 S6 Standard surface 6.057 1.568 1.785 / 25.72 2.11 S7 Standard surface -53.134 0.820 2.24 S8 Standard surface 5.708 2.058 1.593 / 68.62 2.53 S9 Standard surface -4.199 0.705 1.785 / 25.72 2.49 S10 Standard surface 8.760 0.086 2.54 S11 even aspherical surface 9.899 2.084 1.535 / 55.71 2.55 11.026 S12 even aspherical surface -2.866 0.085 2.76 -4.499 S13 even aspherical surface -32.589 0.841 1.640 / 23.50 2.79 -102.742 S14 even aspherical surface 19.916 0.235 3.24 -60.493 S15 even aspherical surface -10.799 1.684 1.535 / 55.71 4.09 -113.623 S16 even aspherical surface -21.960 2.420 4.34 -106.537 S17 Standard surface INF 0.710 1.517 / 64.21 4.81 S18 Standard surface INF 0.918 4.89 IMA Standard surface INF 5.00

[0103] In Table 3, the surface numbers are assigned according to the surface sequence of each lens. For example, surfaces S1 and S2 are the object-side and image-side surfaces of the first lens L1, respectively; surfaces S3 and S4 are the object-side and image-side surfaces of the second lens L2, respectively, and so on. "STO" represents the aperture stop of the lens. The radius of curvature represents the degree of curvature of the corresponding lens surface. A positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. "INF" indicates that the surface is flat and the radius of curvature is infinite. "IMA" represents the image plane. The thickness represents the central axial distance between the current surface and the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light. A blank space indicates that the current position is air and the refractive index is 1. The Abbe number vd is an index used to represent the dispersion ability of a transparent medium. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less severe the dispersion of the medium, the larger the Abbe number.

[0104] In this second embodiment, the second lens L2, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are aspherical lenses, with both their object-side and image-side surfaces being aspherical. Their aspherical surface shape equation Z satisfies:

[0105] In Embodiment 2 of this application, the aspherical lens of the lens system 100 satisfies the following formula:

[0106]

[0107] Where z is the axial sagitta in the Z-direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the fitted conic coefficient; A, B, C, D, E, F, and G are the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order aspherical coefficients corresponding to the aspherical surface; and the units of Z, r, and c are all mm.

[0108] Table 4 Aspherical coefficients of the lens system

[0109] Face number A B C D E F G S3 7.845629E-03 -2.766126E-04 1.746946E-05 -1.573317E-06 5.218962E-07 -8.176162E-08 4.356174E-09 S4 1.174681E-03 3.648703E-04 -1.193231E-04 2.061856E-05 -7.852916E-07 -1.902493E-07 1.755596E-08 S11 1.085642E-03 -3.077058E-05 9.115944E-06 -7.498461E-06 -2.313722E-08 1.919360E-07 -1.869182E-08 S12 -1.146664E-03 5.704745E-04 4.350220E-05 -8.524388E-06 -6.741791E-07 1.138316E-08 1.118121E-08 S13 -1.650697E-02 6.617663E-04 1.177017E-04 6.388471E-06 -4.674952E-06 2.685741E-07 6.487660E-09 S14 -1.984110E-02 2.822501E-03 -1.740621E-04 5.824978E-06 1.710877E-07 -4.149889E-08 1.800809E-09 S15 7.749111E-03 -3.776151E-04 2.989700E-06 4.154678E-07 7.847124E-11 -1.129150E-09 1.886892E-11 S16 4.539574E-03 -5.838716E-04 2.318678E-05 2.350408E-07 -3.203855E-08 2.325903E-10 7.261643E-13

[0110] In Table 4, 7.845629E-03 indicates that the coefficient A for surface number S3 is 7.845629 * 10. -3 And so on.

[0111] Furthermore, several performance tests were conducted on the lens system 100 provided in Embodiment 2, and the specific test results are as follows:

[0112] Figure 7 This is an axial aberration curve diagram of a lens system provided in Embodiment 2 of this application. Figure 7 As shown, the vertical direction represents the normalized aperture, with 0 indicating the optical axis, and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the figure represent different wavelengths of system imaging, determined by... Figure 7 It can be seen that the axial aberrations of the normalized apertures of different wavelengths from 0 to 1.0 are all controlled within the range of (-0.06 mm, +0.06 mm), indicating that the lens system 100 provided in Embodiment 2 of this application has achieved good control of spherical aberration at each wavelength, which can meet the requirements of wide spectrum applications.

[0113] Figure 8 This is a ray fan diagram of a lens system provided in Embodiment 2 of this application. Ray fan diagrams are one of the commonly used evaluation methods by optical designers. For example... Figure 8 As shown, in a single image, the horizontal axis represents the normalized beam aperture, and the vertical axis represents the transverse aberration. Ideally, each curve should perfectly coincide with the horizontal axis, in which case all rays in that field of view focus at the same point on the image plane; the vertical axis in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The fan plot can not only reflect monochromatic aberrations of different wavelengths but also the magnitude of transverse chromatic aberration. Figure 8 It can be seen that the system closely approximates the horizontal axis at each wavelength in each field of view, indicating that the transverse aberration of each wavelength is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the chromatic aberration of the system is also well corrected, thus ensuring that the optical system can achieve the high-resolution imaging requirements.

[0114] Figure 9 This is a field curvature distortion diagram of a lens system provided in Embodiment 2 of this application, such as... Figure 9 As shown, in the coordinate system on the left, the horizontal axis represents the field curvature of the lens system, in mm; the vertical axis represents the normalized image height, without units. In the coordinate system on the right, the horizontal axis represents the distortion (F-Tan(Theta)), in %; the vertical axis represents the normalized image height, without units. Figure 9As can be seen, the lens system provided in this embodiment effectively controls the field curvature of light from wavelengths of 436nm to 850nm, meaning that during imaging, the difference in image quality between the center and the periphery is small. Simultaneously, the distortion of the lens system is well corrected, resulting in minimal imaging distortion.

[0115] Figure 10 This is a relative illumination diagram of a lens system provided in Embodiment 2 of this application. Relative illumination refers to the ratio of the illumination at different coordinate points on the image plane to the illumination at the center point, that is, the ratio of the illumination of other fields of view to the illumination of the center field of view. It is an important evaluation index of imaging optical systems. Figure 10 In this diagram, the vertical axis represents relative illumination, and the horizontal axis represents the field of view angle. In an imaging optical system, if the relative illumination of a certain field of view is low, vignetting is likely to occur. Figure 10 It can be seen that the relative illumination of this lens system is greater than 40%, which meets the requirements of common lens systems for this indicator, and the vignetting control performance is good.

[0116] In summary, the lens system provided in Embodiment 2 of this application consists of four standard glass spherical elements and four non-curved plastic lens elements. The number of lenses is reasonable, the structure is simple and compact, and the optical power and position of each lens element are reasonable, which can achieve day and night confocality and high resolution. At the same time, the wide-angle, large-area compact lens system has greater competitiveness in the market.

[0117] Example 3

[0118] Figure 11 This is a schematic diagram of a lens system provided in Embodiment 3 of this application. Figure 11 As shown, the lens system 100 provided in Embodiment 3 of this application includes a first lens L1, a second lens L2, an aperture stop, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8 arranged sequentially along the optical axis from the object plane to the image plane; along the optical axis from the object plane to the image plane,

[0119] The first lens L1 is a glass spherical lens with negative optical power, a convex object-side surface, and a concave image-side surface; the second lens L2 is a plastic aspherical lens with negative optical power, a concave object-side surface, and a convex image-side surface; the third lens L3 is a glass spherical lens with positive optical power, and its object-side surface is convex; the fourth lens L4 is a glass spherical lens with positive optical power, and both its object-side and image-side surfaces are convex; the fifth lens L5 is a glass spherical lens with negative optical power, and both its object-side and image-side surfaces are concave; the sixth lens L6 is a plastic aspherical lens with positive optical power, and both its object-side and image-side surfaces are convex; the seventh lens L7 is a plastic aspherical lens with negative optical power; and the eighth lens L8 is a plastic aspherical lens with negative optical power.

[0120] A flat glass CG is positioned in the optical path between the eighth lens L8 and the image plane. The flat glass CG protects the photosensitive chip in the imaging sensor. The imaging chip converts the light signals collected by the lens system into electrical signals, thereby ensuring the imaging effect of the lens system.

[0121] As one possible implementation method, please refer to [reference]. Figure 11 The lens system 100 provided in Embodiment 3 of this application has a focal length f of 3.54mm, an aperture of F# of 2.00, and a field of view D. FOV =180°, total optical length TTL: 19.99mm. Table 5 shows the optical physical parameters of the first lens L1 to the eighth lens L8 in a lens system 100 provided in Embodiment 3 of this application. The units for radius of curvature R and thickness d are millimeters (mm). Table 6 shows the aspherical coefficient values ​​of the aspherical lenses in the lens system 100 provided in Embodiment 3 of this application.

[0122] Table 5 Design values ​​of optical physical parameters for the lens system

[0123] Face number Surface type Radius of curvature (mm) Thickness (mm) (nd) / (vd) Half-diameter (mm) k value S1 Standard surface 14.542 0.789 1.786 / 44.51 5.26 S2 Standard surface 3.233 3.067 2.95 S3 even aspherical surface -3.348 1.808 1.545 / 55.99 2.66 -0.482 S4 even aspherical surface -7.603 0.255 2.15 -12.544 S5 STO INF -0.208 1.99 S6 Standard surface 5.917 1.821 1.785 / 25.72 2.11 S7 Standard surface -98.482 0.551 2.27 S8 Standard surface 5.657 2.243 1.593 / 68.35 2.48 S9 Standard surface -4.161 0.705 1.785 / 25.72 2.47 S10 Standard surface 8.359 0.058 2.62 S11 even aspherical surface 10.071 2.002 1.545 / 55.99 2.60 10.050 S12 even aspherical surface -2.867 0.035 2.81 -4.195 S13 even aspherical surface -61.449 0.741 1.640 / 23.50 2.84 11.340 S14 even aspherical surface 21.995 0.394 3.24 -32.246 S15 even aspherical surface -9.622 1.476 1.535 / 55.71 4.25 -52.984 S16 even aspherical surface -22.999 2.290 4.42 -11.478 S17 Standard surface INF 0.710 1.517 / 64.21 4.85 S18 Standard surface INF 1.257 4.93 IMA Standard surface INF 5.00

[0124] In Table 5, the surface numbers are assigned according to the surface sequence of each lens. For example, surfaces S1 and S2 are the object-side and image-side surfaces of the first lens L1, respectively; surfaces S3 and S4 are the object-side and image-side surfaces of the second lens L2, respectively, and so on. "STO" represents the aperture stop of the lens. The radius of curvature represents the degree of curvature of the corresponding lens surface. A positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. "INF" indicates that the surface is flat and the radius of curvature is infinite. "IMA" represents the image plane. The thickness represents the central axial distance between the current surface and the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light. A blank space indicates that the current position is air and the refractive index is 1. The Abbe number (vd) is an index used to represent the dispersion ability of a transparent medium. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less severe the dispersion of the medium, the larger the Abbe number.

[0125] In this third embodiment, the second lens L2, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are aspherical lenses, with both their object-side and image-side surfaces being aspherical. Their aspherical surface shape equation Z satisfies:

[0126] In Embodiment 3 of this application, the aspherical lens of the lens system 100 satisfies the following formula:

[0127]

[0128] Where z is the axial sagitta in the Z-direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, numerically the reciprocal of the radius of curvature; k is the fitted conic coefficient; A, B, C, D, E, F, and G are the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order aspherical coefficients corresponding to the aspherical surfaces; and the units of Z, r, and c are all mm. Table 6 shows the aspherical coefficient values ​​used in the embodiments.

[0129] Table 6 Aspherical coefficients of the lens system

[0130] Face number A B C D E F G S3 7.955948E-03 -3.006972E-04 2.087108E-05 -7.621426E-07 4.065496E-07 -1.091241E-07 7.791729E-09 S4 1.467083E-03 3.157361E-04 -9.203715E-05 1.857471E-05 -9.565472E-07 -2.601853E-07 3.315459E-08 S11 1.520819E-03 -2.936275E-05 1.312764E-05 -7.625882E-06 -1.325112E-07 1.782476E-07 -1.317409E-08 S12 -1.656771E-03 5.433762E-04 4.570438E-05 -1.016038E-05 -5.396336E-07 6.409134E-09 1.108111E-08 S13 -1.655560E-02 6.445715E-04 1.069836E-04 6.727943E-06 -4.610246E-06 2.642774E-07 6.316594E-09 S14 -1.939080E-02 2.834288E-03 -1.739711E-04 6.068643E-06 1.463997E-07 -4.983708E-08 2.454953E-09 S15 8.687666E-03 -4.011766E-04 2.167347E-06 4.636601E-07 1.557357E-10 -1.014180E-09 1.502428E-11 S16 4.518249E-03 -5.336631E-04 2.313675E-05 2.332048E-07 -3.437353E-08 2.243906E-10 3.372233E-12

[0131] In Table 6, 7.955948E-03 indicates that the coefficient A for surface number S3 is 7.955948 * 10. -3 And so on.

[0132] Furthermore, several performance tests were conducted on the lens system 100 provided in Embodiment 3, and the specific test results are as follows:

[0133] Figure 12 This is an axial aberration curve diagram of a lens system provided in Embodiment 3 of this application. Figure 12 As shown, the vertical direction represents the normalized aperture, with 0 indicating the optical axis, and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the figure represent different wavelengths of system imaging, determined by... Figure 12 It can be seen that the axial aberrations of the normalized apertures of different wavelengths from 0 to 1.0 are all controlled within the range of (-0.06 mm, +0.06 mm), indicating that the lens system 100 provided in Embodiment 3 of this application has achieved good control of spherical aberration at each wavelength, which can meet the requirements of wide spectrum applications.

[0134] Figure 13 This is a ray fan diagram of a lens system provided in Embodiment 3 of this application. Ray fan diagrams are one of the commonly used evaluation methods by optical designers. For example... Figure 13 As shown, in a single image, the horizontal axis represents the normalized beam aperture, and the vertical axis represents the transverse aberration. Ideally, each curve should perfectly coincide with the horizontal axis, in which case all rays in that field of view focus at the same point on the image plane; the vertical axis in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The fan plot can not only reflect monochromatic aberrations of different wavelengths but also the magnitude of transverse chromatic aberration. Figure 13 It can be seen that the system closely approximates the horizontal axis at each wavelength in each field of view, indicating that the transverse aberration of each wavelength is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the chromatic aberration of the system is also well corrected, thus ensuring that the optical system can achieve the high-resolution imaging requirements.

[0135] Figure 14 This is a field curvature distortion diagram of a lens system provided in Embodiment 3 of this application, such as... Figure 14 As shown, in the coordinate system on the left, the horizontal axis represents the field curvature of the lens system, in mm; the vertical axis represents the normalized image height, without units. In the coordinate system on the right, the horizontal axis represents the distortion (F-Tan(Theta)), in %; the vertical axis represents the normalized image height, without units. Figure 14 As can be seen, the lens system provided in this embodiment effectively controls the field curvature of light from wavelengths of 436nm to 850nm, meaning that during imaging, the difference in image quality between the center and the periphery is small. Simultaneously, the distortion of the lens system is well corrected, resulting in minimal imaging distortion.

[0136] Figure 15 This is a relative illumination diagram of a lens system provided in Embodiment 3 of this application. Relative illumination refers to the ratio of the illumination at different coordinate points on the image plane to the illumination at the center point, that is, the ratio of the illumination at other fields of view to the illumination at the center field of view. It is an important evaluation index of imaging optical systems. Figure 15 In this diagram, the vertical axis represents relative illumination, and the horizontal axis represents the field of view angle. In an imaging optical system, if the relative illumination of a certain field of view is low, vignetting is likely to occur. Figure 15 It can be seen that the relative illumination of this lens system is greater than 40%, which meets the requirements of common lens systems for this indicator, and the vignetting control performance is good.

[0137] In summary, the lens system provided in Embodiment 3 of this application consists of four standard glass spherical elements and four non-curved plastic lens elements. The number of lenses is reasonable, the structure is simple and compact, and the optical power and position of each lens element are reasonable, which can achieve day and night confocality and high resolution. At the same time, the wide-angle, large-area compact lens system has greater competitiveness in the market.

[0138] In summary, the optical physical parameters of the first lens to the eighth lens in Embodiments 1, 2 and 3 of this application are shown in Table 7.

[0139] Table 7 Design values ​​of optical physical parameters for the lens system

[0140]

[0141]

[0142] Note that the above are merely preferred embodiments and the technical principles employed in this application. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A lens system, characterized in that, It includes a first lens, a second lens, an aperture stop, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially along the optical axis from the object plane to the image plane; along the direction from the object plane to the image plane, The first lens is a glass spherical lens with negative optical power, a convex object-side surface, and a concave image-side surface; the second lens is a plastic aspherical lens with negative optical power, a concave object-side surface, and a convex image-side surface; the third lens is a glass spherical lens with positive optical power and a convex object-side surface; the fourth lens is a glass spherical lens with positive optical power and both its object-side and image-side surfaces are convex; the fifth lens is a glass spherical lens with negative optical power and both its object-side and image-side surfaces are concave; the sixth lens is a plastic aspherical lens with positive optical power and both its object-side and image-side surfaces are convex. The seventh lens is a plastic aspherical lens with negative optical power; the eighth lens is a plastic aspherical lens with negative optical power. The first lens and the second lens form a first lens group, and the first lens group satisfies the following relationship: -1.105 ≤ φ A / φ≤-0.985; Where, φ A φ is the combined optical power of the first lens group, and φ is the optical power of the lens system.

2. The lens system according to claim 1, characterized in that, The third lens, the fourth lens, and the fifth lens constitute a second lens group, which satisfies the following relationship: 0.535 ≤ φ B / φ≤0.645; Where, φ B φ is the combined optical power of the second lens group, and φ is the optical power of the lens system.

3. The lens system according to claim 1, characterized in that, The sixth lens, the seventh lens, and the eighth lens constitute a third lens group, which satisfies the following relationship: 0.525 ≤ φ C / φ≤0.655; Where, φ C φ is the combined optical power of the third lens group, and φ is the optical power of the lens system.

4. The lens system according to claim 1, characterized in that, The optical power of the lens system satisfies the following relationship: -0.715≤φ1 / φ≤-0.665;-0.305≤φ2 / φ≤-0.235; 0.465≤φ3 / φ≤0.535; 0.755≤φ6 / φ≤0.925; -0.235≤φ7 / φ≤-0.125; -0.125≤φ8 / φ≤-0.065; Wherein, φ1 represents the optical power of the first lens, φ2 represents the optical power of the second lens, φ3 represents the optical power of the third lens, φ6 represents the optical power of the sixth lens, φ7 represents the optical power of the seventh lens, φ8 represents the optical power of the eighth lens, and φ represents the optical power of the lens system.

5. The lens system according to claim 1, characterized in that, The fourth lens and the fifth lens are cemented together to form a cemented lens group. The optical power φ45 of the cemented lens group and the optical power φ of the lens system satisfy the following relationship: -0.075≤φ45 / φ≤-0.

015.

6. The lens system according to claim 1, characterized in that, The lens system satisfies the following relationship: 1.025 ≤ D1 / (F no *Y max ≤1.075; Where D1 represents the maximum effective diameter of the first lens, F no Y represents the aperture of the lens system. max This represents the maximum image circle radius of the lens system.

7. The lens system according to claim 1, characterized in that, The sagitta Sag7 of the object side of the seventh lens and the half-aperture d7 of the object side of the seventh lens satisfy: -0.265≤Sag7 / d7≤-0.215; The full-aperture sagitta Sag7 of the image-side surface of the seventh lens A The half-aperture sagitta Sag7 of the image-side surface of the seventh lens B Satisfies: 0.185≤Sag7 B / Sag7 A ≤0.

325.

8. The lens system according to claim 1, characterized in that, The image-side elevation Sag8 of the eighth lens and the half-aperture d8 of the image-side surface of the eighth lens satisfy the following condition: -0.095≤Sag8 / d8≤-0.045; The full-aperture sagitta Sag8 of the object-side surface of the eighth lens A The half-aperture sagitta Sag8 of the object side surface of the eighth lens B Satisfies: -0.028 ≤ Sag8 B / Sag8 A ≤-0.

008.

9. The lens system according to claim 1, characterized in that, It also includes a flat glass plate disposed in the optical path between the eighth lens and the image plane.

Images