A large image surface 450mm fixed focus lens

Abstract

The application relates to the technical field of optical systems, in particular to a large-image-surface 450mm fixed-focus lens which comprises a plane lens, a first lens group and a second lens group which are sequentially distributed; the first lens group comprises a first double-cemented lens group, a second double-cemented lens group, a first lens, a third double-cemented lens group and a fourth double-cemented lens group which are sequentially distributed, reasonable light power distribution and light radius matching of the application greatly expand the effective imaging target surface coverage range of the 450mm fixed-focus lens, the large-size image sensor can be adapted, the effective photosensitive area of the detector is fully utilized, and pixel resource waste is reduced.

Description

Technical Field

[0001] This invention relates to the field of optical system technology, and in particular to a large-image-size 450mm fixed-focus lens. Background Technology

[0002] Fixed-focus lenses with a focal length of around 450mm enable clear observation and recording of distant targets. Currently, most 450mm fixed-focus lenses on the market, designed to meet basic imaging needs at specific working distances, often employ a relatively simplified design approach in terms of lens group configuration, lens material selection, and power distribution. While ensuring the central field-of-view resolution meets basic requirements, the image sensor size is typically limited to a small range, for example, only compatible with image sensors of 1 inch or smaller. Meanwhile, with continuous advancements in semiconductor manufacturing processes, the image sensor sensor size continues to increase to improve light sensitivity, placing higher demands on the imaging coverage of the supporting optical system. However, at the specific specification of 450mm focal length, the inherently narrow field of view of telephoto lenses means that a limited image sensor size translates to a correspondingly narrower field of view. This limitation prevents 450mm fixed-focus lenses from fully utilizing the effective light-sensitive area of ​​large-area detectors, resulting in wasted detector pixel resources and hindering further improvements in the overall system imaging performance. In addition, the smaller imaging surface also limits the amount of information contained within a unit field of view. In situations where high-precision observation of a large range of target scenes is required, existing 450mm lenses often need to compensate for the insufficient field of view by means of scanning and stitching, which increases the complexity of the system and the cost of use. Summary of the Invention

[0003] The purpose of this invention is to provide a large-image-size 450mm fixed-focus lens to solve the problem that existing 450mm fixed-focus lenses have insufficient effective light-sensing area and limited field of view coverage when adapted to larger target detectors, making it difficult to meet the matching requirements of high-resolution large target imaging systems.

[0004] The technical solution of the present invention is: a large image plane 450mm fixed focal length lens, comprising a plane lens, a first lens group and a second lens group arranged in sequence; The first lens group includes a first cemented doublet lens group, a second cemented doublet lens group, a first lens, a third cemented doublet lens group, and a fourth cemented doublet lens group arranged sequentially. The first cemented doublet lens group includes: The first cemented lens is a convex lens with positive refractive power; The second cemented lens is a concave lens with negative refractive power; The second cemented doublet lens group includes: Third cemented lens, a concave lens with negative refractive power; The fourth type of cemented lens is a convex lens with positive refractive power. The first lens is a convex lens with positive refractive power; The third cemented doublet lens group includes: The fifth cemented lens is a concave lens with negative refractive power; The sixth cemented lens is a convex lens with positive refractive power; The fourth cemented doublet lens group includes: The seventh cemented lens is a convex lens with positive refractive power; The eighth cemented lens is a concave lens with negative refractive power. The light transmission radius p of the plane lens satisfies: 18.6 < p < 20.7; The relationship between the light transmission radii of each lens in the first lens group and the planar lens is as follows: 0.8<pi / p<1.3, i=1, 2, 3, 4, 5, 6, 7, 8, 9; Where p1, p2, p3, p4, p5, p6, p7, p8, and p9 are the light transmission radii of the first cemented lens, the second cemented lens, the third cemented lens, the fourth cemented lens, the first lens, the fifth cemented lens, the sixth cemented lens, the seventh cemented lens, and the eighth cemented lens, respectively.

[0005] Preferably, the curvature radii of the first lens group satisfy the following relationship: 0.004<|(Ri+Ri') / (Ri-Ri')|<5.426, i=1, 2, 3, 4, 5, 6, 7, 8, 9; Where Ri is the radius of curvature of the incident end of each lens in the first lens group, and Ri' is the radius of curvature of the exit end of each lens in the first lens group.

[0006] Preferably, the refractive index and Abbe number of the first lens group and the plane lens satisfy the following relationship: 0.9<ndi / nd<1.2, i=1, 2, 3, 4, 5, 6, 7, 8, 9; Wherein, nd is the refractive index of the plane lens; nd1, nd2, nd3, nd4, nd5, nd6, nd7, nd8, and nd9 are the refractive indices of the first cemented lens, the second cemented lens, the third cemented lens, the fourth cemented lens, the first lens, the fifth cemented lens, the sixth cemented lens, the seventh cemented lens, and the eighth cemented lens, respectively. 0.2<vdi / vd<1.1, i=1, 2, 3, 4, 5, 6, 7, 8, 9; Where vd is the Abbe number of the plane lens; vd1, vd2, vd3, vd4, vd5, vd6, vd7, vd8, and vd9 are the Abbe numbers of the first, second, third, fourth, first, fifth, sixth, seventh, and eighth cemented lenses, respectively.

[0007] Preferably, the second lens group comprises, in sequence: The fifth cemented doublet lens group; The second lens is a concave lens with negative refractive power; The third lens is a convex lens with positive refractive power; The fourth lens is a convex lens with positive refractive power; The fifth lens is a concave lens with negative refractive power; The sixth lens is a convex lens with positive refractive power; The seventh lens is a convex lens with positive refractive power.

[0008] Preferably, the fifth cemented lens group includes a ninth cemented lens and a tenth cemented lens, wherein the ninth cemented lens is a concave lens with negative refractive power and the tenth cemented lens is a convex lens with positive refractive power.

[0009] Preferably, the light transmission radii of each lens in the second lens group and the planar lens satisfy the following relationship: 1.1<pi / p<2.7, i=10, 11, 12, 13, 14, 15, 16, 17; Where p10, p11, p12, p13, p14, p15, p16, and p17 are the light transmission radii of the ninth cemented lens, the tenth cemented lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively.

[0010] Preferably, the curvature radii of the second lens group satisfy the following relationship: 0.28<|(Ri+Ri') / (Ri-Ri')|<8.41; i=10, 11, 12, 13, 14, 15, 16, 17; Where Ri is the radius of curvature of the incident end of each lens in the second lens group, and Ri' is the radius of curvature of the exit end of each lens in the second lens group.

[0011] Preferably, the refractive index and Abbe number of the second lens group and the plane lens satisfy the following relationship: 0.8<ndi / nd<1.3, i=10, 11, 12, 13, 14, 15, 16, 17; nd10, nd11, nd12, nd13, nd14, nd15, nd16, and nd17 are the refractive indices of the ninth cemented lens, the tenth cemented lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively. 0.2<vdi / vd<1.7, i=10, 11, 12, 13, 14, 15, 16, 17; Where vd10, vd11, vd12, vd13, vd14, vd15, vd16, and vd17 are the Abbe numbers of the ninth cemented lens, the tenth cemented lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively.

[0012] Preferably, the thickness H of the planar lens satisfies: 3.8 < H < 4.1; In the first lens group, the central thickness of each lens and the plane lens satisfy the following relationship: 0.4<hi / H<2.2, i=1, 2, 3, 4, 5, 6, 7, 8, 9; Where h1, h2, h3, h4, h5, h6, h7, h8, and h9 are the center thicknesses of the first cemented lens, the second cemented lens, the third cemented lens, the fourth cemented lens, the first lens, the fifth cemented lens, the sixth cemented lens, the seventh cemented lens, and the eighth cemented lens, respectively.

[0013] Preferably, in the second lens group, the center thickness of each lens satisfies the following relationship with the planar lens: 0.6<hi / H<3.1, i=10, 11, 12, 13, 14, 15, 16, 17; h10, h11, h12, h13, h14, h15, h16, and h17 are the center thicknesses of the ninth cemented lens, the tenth cemented lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively.

[0014] Compared with the prior art, the advantages of the present invention are: It solves the technical problems of existing 450mm focal length fixed-focus lenses, such as small imaging target surface, narrow field of view, and inability to adapt to large target surface detectors. The reasonable allocation of optical power and matching of light transmission radius greatly expand the effective imaging target surface coverage of 450mm focal length fixed-focus lenses, which can be adapted to large-size image sensors, make full use of the effective light-sensing area of ​​the detector, reduce pixel resource waste, and significantly improve the overall imaging performance of the system.

[0015] (2) At the same time, the effective field of view of the lens is widened, which increases the amount of imaging information per unit field of view. There is no need to rely on scanning and stitching to make up for the field of view defects. On the basis of ensuring high-definition observation effect of distant targets, the overall structure of the equipment is simplified, the cost of equipment use and maintenance is reduced, and it is suitable for large-scale and high-precision observation operation scenarios. Its practicality and adaptability are greatly improved. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the structure of the large image sensor 450mm fixed focal length lens described in this invention; Figure 2 This is a schematic diagram of the structure of the first lens group described in this invention; Figure 3 This is a schematic diagram of the structure of the second lens group described in this invention; Figure 4 The field curve diagram and distortion curve diagram described in this invention; Figure 5 This is the vertical axis color difference analysis diagram described in this invention; Figure 6 This is the dot plot diagram described in this invention.

[0017] Explanation of reference numerals in the attached figures: 1. Plane lens; 2. First lens group; 21. First cemented doublet lens group; 211. First cemented lens; 212. Second cemented lens; 22. Second cemented doublet lens group; 221. Third cemented lens; 222. Fourth cemented lens; 23. First lens; 24. Third cemented doublet lens group; 241. Fifth cemented lens; 242. Sixth cemented lens; 25. Fourth cemented doublet lens group; 251. Seventh cemented lens; 252. Eighth cemented lens; 3. Second lens group; 31. Fifth cemented doublet lens group; 311. Ninth cemented lens; 312. Tenth cemented lens; 32. Second lens; 33. Third lens; 34. Fourth lens; 35. Fifth lens; 36. Sixth lens; 37. Seventh lens. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0019] like Figures 1 to 6As shown, a 450mm fixed-focus lens with a large image sensor includes a plane lens, a first lens group, and a second lens group arranged sequentially. The plane lens is closer to the image sensor (IMA), and the second lens group is closer to the object side. The relative positions of the plane lens, the first lens group, and the second lens group are fixed, thus forming a fixed-focus lens.

[0020] In this embodiment, stop is an aperture stop. In each embodiment, the aperture stop stop is disposed between the first lens group and the second lens group. IMA is the image plane. When the optical system is used as an imaging optical system for a camera or digital camera, the image plane IMA corresponds to a solid-state imaging device (photoelectric conversion device), such as a CCD sensor or a CMOS sensor. When the optical system of the present invention is used as an imaging optical system for a silver halide film camera, the image plane IMA corresponds to the film plane.

[0021] About plane lenses: The incident and exit surfaces of a plane lens are both planes.

[0022] The light transmission radius p of a plane lens satisfies: 18.6 < p < 20.7; Preferably, the light transmission radius p of the plane lens is 19.28 mm; The thickness H of the plane lens satisfies: 3.8 < H < 4.1; Preferably, the thickness H of the plane lens is 3.94 mm; The refractive index and Abbe number of a plane lens satisfy the following ranges: 1.5 < nd < 1.8, 59 < vd < 63 In this embodiment, the plane lens has an Abbe number of 61.25, a refractive index of 1.59, and is made of H-ZK7 material.

[0023] Regarding the first lens group: The first lens group includes a first cemented doublet lens group, a second cemented doublet lens group, a first lens, a third cemented doublet lens group, and a fourth cemented doublet lens group arranged sequentially. The first cemented doublet lens group includes a first cemented lens and a second cemented lens cemented together, wherein the first cemented lens is a convex lens with positive refractive power, and the second cemented lens is a concave lens with negative refractive power. The second cemented doublet lens group includes a third cemented lens and a fourth cemented lens cemented together, wherein the third cemented lens is a concave lens with negative refractive power, and the fourth cemented lens is a convex lens with positive refractive power. The first lens is a convex lens with positive refractive power. The third cemented doublet lens group includes a fifth cemented lens and a sixth cemented lens cemented together, wherein the fifth cemented lens is a concave lens with negative refractive power, and the sixth cemented lens is a convex lens with positive refractive power. The fourth cemented doublet lens group includes a seventh cemented lens and an eighth cemented lens cemented together, wherein the seventh cemented lens is a convex lens with positive refractive power, and the eighth cemented lens is a concave lens with negative refractive power.

[0024] The relationship between the light transmission radii of each lens in the first lens group and the plane lens is as follows: 0.8<pi / p<1.3, i=1, 2, 3, 4, 5, 6, 7, 8, 9; Where p1, p2, p3, p4, p5, p6, p7, p8, and p9 are the light transmission radii of the first cemented lens, the second cemented lens, the third cemented lens, the fourth cemented lens, the first lens, the fifth cemented lens, the sixth cemented lens, the seventh cemented lens, and the eighth cemented lens, respectively.

[0025] Preferably, the light transmission radius of the first cemented lens is 19.33 mm; the light transmission radius of the second cemented lens is 20.05 mm; the light transmission radius of the third cemented lens is 21.77 mm; the light transmission radius of the fourth cemented lens is 22.01 mm; the light transmission radius of the first lens is 22.28 mm; the light transmission radius of the fifth cemented lens is 17.64 mm; the light transmission radius of the sixth cemented lens is 17.85 mm; the light transmission radius of the seventh cemented lens is 18.26 mm; and the light transmission radius of the eighth cemented lens is 18.34 mm.

[0026] The relationship satisfied by the radius of curvature of the first lens group is: 0.004<|(Ri+Ri') / (Ri-Ri')|<5.426, i=1, 2, 3, 4, 5, 6, 7, 8, 9; Where Ri is the radius of curvature of the incident end of each lens in the first lens group, and Ri' is the radius of curvature of the exit end of each lens in the first lens group.

[0027] Preferably, the radius of curvature R1 of the incident end of the first cemented lens is 55.83 mm; the radius of curvature R1' of the exit end of the first cemented lens is 81.84 mm; the radius of curvature R2 of the incident end of the second cemented lens is 81.84 mm; the radius of curvature R2' of the exit end of the second cemented lens is 1667.68 mm; the radius of curvature R3 of the incident end of the third cemented lens is -139.18 mm; the radius of curvature R3' of the exit end of the third cemented lens is 335.53 mm; the radius of curvature R4 of the incident end of the fourth cemented lens is 335.53 mm; the radius of curvature R4' of the exit end of the fourth cemented lens is 137.7 mm; and the radius of curvature R5 of the incident end of the first lens is 259.49 mm. mm; the radius of curvature R5' of the exit end of the first lens is -390.95 mm; the radius of curvature R6 of the entrance end of the fifth cemented lens is -68.05 mm; the radius of curvature R6' of the exit end of the fifth cemented lens is 75.57 mm; the radius of curvature R7 of the entrance end of the sixth cemented lens is 75.57 mm; the radius of curvature R7' of the exit end of the sixth cemented lens is 131.18 mm; the radius of curvature R8 of the entrance end of the seventh cemented lens is 258.66 mm; the radius of curvature R8' of the exit end of the seventh cemented lens is -677 mm; the radius of curvature R9 of the entrance end of the eighth cemented lens is -677 mm; the radius of curvature R9' of the exit end of the eighth cemented lens is 1358.24 mm.

[0028] In the first lens group, the central thickness of each lens satisfies the following relationship with the plane lens: 0.4<hi / H<2.2, i=1, 2, 3, 4, 5, 6, 7, 8, 9; Where h1, h2, h3, h4, h5, h6, h7, h8, and h9 are the center thicknesses of the first cemented lens, the second cemented lens, the third cemented lens, the fourth cemented lens, the first lens, the fifth cemented lens, the sixth cemented lens, the seventh cemented lens, and the eighth cemented lens, respectively.

[0029] Preferably, the thickness of the first cemented lens is 5.86 mm; the thickness of the second cemented lens is 6.74 mm; the thickness of the third cemented lens is 8.48 mm; the thickness of the fourth cemented lens is 5.9 mm; the thickness of the first lens is 2.6 mm; the thickness of the fifth cemented lens is 5.38 mm; the thickness of the sixth cemented lens is 5.2 mm; the thickness of the seventh cemented lens is 2.83 mm; and the thickness of the eighth cemented lens is 1.75 mm.

[0030] The refractive indices and Abbe numbers of the first lens group and the plane lens satisfy the following relationship: 0.9<ndi / nd<1.2, i=1, 2, 3, 4, 5, 6, 7, 8, 9; Where nd is the refractive index of the plane lens; nd1, nd2, nd3, nd4, nd5, nd6, nd7, nd8, and nd9 are the refractive indices of the first cemented lens, the second cemented lens, the third cemented lens, the fourth cemented lens, the first lens, the fifth cemented lens, the sixth cemented lens, the seventh cemented lens, and the eighth cemented lens, respectively. Specifically, 0.96 < nd1 / nd < 1.13 1.07 < nd2 / nd < 1.18 0.94 < nd3 / nd < 1.09 1.09 < nd4 / nd < 1.14 1.11 < nd5 / nd < 1.17 1.16 < nd6 / nd < 1.2, 0.97 < nd7 / nd < 1.12 0.93 < nd8 / nd < 1.06 1.12 < nd9 / nd < 1.19.

[0031] The Abbe numbers of the first lens group and the plane lens satisfy the following relationship: 0.2<vdi / vd<1.1, i=1, 2, 3, 4, 5, 6, 7, 8, 9; Where vd is the Abbe number of the plane lens; vd1, vd2, vd3, vd4, vd5, vd6, vd7, vd8, and vd9 are the Abbe numbers of the first, second, third, fourth, first, fifth, sixth, seventh, and eighth cemented lenses, respectively.

[0032] Specifically, 0.42 < vd1 / vd < 0.55 0.37 < vd2 / vd < 0.48 0.78 < vd3 / vd < 1.1 0.69 < vd4 / vd < 0.74 0.61 < vd5 / vd < 0.72 0.63 < vd6 / vd < 0.71 0.48 < vd7 / vd < 0.53 0.52 < vd8 / vd < 0.61 0.35 < vd9 / vd < 0.42.

[0033] Since refractive index and Abbe number are material specifications determined by the specific lens material, in this embodiment, the first cemented lens is made of H-BaF13; the second cemented lens is made of H-ZF56A; the third cemented lens is made of H-ZK20; the fourth cemented lens is made of H-ZLaF01; the first lens is made of H-ZLaF44; the fifth cemented lens is made of H-ZLaF31A; the sixth cemented lens is made of H-ZF8; the seventh cemented lens is made of H-F2; and the eighth cemented lens is made of H-ZF57.

[0034] Specifically, the air gap between the plane lens and the first cemented doublet lens group is 10 mm; the air gap between the first cemented doublet lens group and the second cemented doublet lens group is 5.58 mm; the air gap between the second cemented doublet lens group and the first lens is 7.11 mm; the air gap between the first lens and the third cemented doublet lens group is 3.72 mm; and the air gap between the third cemented doublet lens group and the fourth cemented doublet lens group is 2.83 mm.

[0035] Regarding the second lens group: The second lens group sequentially includes the second, third, fourth, fifth, sixth, and seventh lenses of the fifth cemented doublet lens group. The fifth cemented doublet lens group includes a ninth and tenth cemented lens cemented together; the ninth cemented lens is a concave lens with negative refractive power, and the tenth cemented lens is a convex lens with positive refractive power. The second lens is a concave lens with negative refractive power; the third lens is a convex lens with positive refractive power; the fourth lens is a convex lens with positive refractive power; the fifth lens is a concave lens with negative refractive power; the sixth lens is a convex lens with positive refractive power; and the seventh lens is a convex lens with positive refractive power.

[0036] The relationship between the light transmission radii of each lens in the second lens group and the plane lens is as follows: 1.1<pi / p<2.7, i=10, 11, 12, 13, 14, 15, 16, 17; Where p10, p11, p12, p13, p14, p15, p16, and p17 are the light transmission radii of the ninth cemented lens, the tenth cemented lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively.

[0037] Preferably, the light transmission radius of the ninth cemented lens is 22.45 mm; the light transmission radius of the tenth cemented lens is 22.7 mm; the light transmission radius of the second lens is 26.43 mm; the light transmission radius of the third lens is 28.5 mm; the light transmission radius of the fourth lens is 29.92 mm; the light transmission radius of the fifth lens is 33.21 mm; the light transmission radius of the sixth lens is 34.98 mm; and the light transmission radius of the seventh lens is 49.4 mm.

[0038] The relationship satisfied by the radius of curvature of the second lens group is as follows: 0.28<|(Ri+Ri') / (Ri-Ri')|<8.41; i=10, 11, 12, 13, 14, 15, 16, 17; Where Ri is the radius of curvature of the incident end of each lens in the second lens group, and Ri' is the radius of curvature of the exit end of each lens in the second lens group.

[0039] Preferably, the radius of curvature R10 of the incident end of the ninth cemented lens is -95.56 mm; the radius of curvature R10' of the exit end of the ninth cemented lens is 223.56 mm. The radius of curvature R11 of the incident end of the tenth cemented lens is 223.56 mm; the radius of curvature R11' of the exit end of the tenth cemented lens is 284.86 mm. The radius of curvature R12 of the incident end of the second lens is -544.9 mm; the radius of curvature R12' of the exit end of the second lens is 279.22 mm. The radius of curvature R13 of the incident end of the third lens is 127.6 mm; the radius of curvature R13' of the exit end of the third lens is 174.07 mm. The radius of curvature R14 of the incident end of the fourth lens is 72.77 mm; the radius of curvature R14' of the exit end of the fourth lens is -661.13 mm. The radius of curvature R15 at the incident end of the fifth lens is 661.14 mm; the radius of curvature R15' at the exit end of the fifth lens is 73.74 mm. The radius of curvature R16 at the incident end of the sixth lens is 74.64 mm; the radius of curvature R16' at the exit end of the sixth lens is 800.68 mm. The radius of curvature R17 at the incident end of the seventh lens is 285.87 mm; the radius of curvature R17' at the exit end of the seventh lens is -1591.26 mm.

[0040] In the second lens group, the central thickness of each lens satisfies the following relationship with the plane lens: 0.6<hi / H<3.1, i=10, 11, 12, 13, 14, 15, 16, 17; h10, h11, h12, h13, h14, h15, h16, and h17 are the center thicknesses of the ninth cemented lens, the tenth cemented lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively.

[0041] Preferably, the thickness of the ninth cemented lens is 2.71 mm; the thickness of the tenth cemented lens is 4.58 mm; the thickness of the second lens is 4.07 mm; the thickness of the third lens is 6.59 mm; and the thickness of the fourth lens is 8.1 mm. The thickness of the fifth lens is 10.92 mm; the thickness of the sixth lens is 9.48 mm; and the thickness of the seventh lens is 9.11 mm.

[0042] The refractive indices of the second lens group and the plane lens satisfy the following relationship: 0.8<ndi / nd<1.3, i=10, 11, 12, 13, 14, 15, 16, 17; nd10, nd11, nd12, nd13, nd14, nd15, nd16, and nd17 are the refractive indices of the ninth cemented lens, the tenth cemented lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively. 0.96 < nd10 / nd < 1.16 0.97 < nd11 / nd < 1.14 0.92 < nd12 / nd < 0.99 1.16 < nd13 / nd < 1.28 0.83 < nd14 / nd < 0.92 1.11 < nd15 / nd < 1.23 0.91 < nd16 / nd < 1.04 0.82 < nd17 / nd < 0.92 The Abbe numbers of the second lens group and the plane lens satisfy the following relationship: 0.2<vdi / vd<1.7, i=10, 11, 12, 13, 14, 15, 16, 17; Where vd10, vd11, vd12, vd13, vd14, vd15, vd16, and vd17 are the Abbe numbers of the ninth cemented lens, the tenth cemented lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively.

[0043] 0.86 < vd10 / vd < 0.98 0.42 < vd11 / vd < 0.51 0.88 < vd12 / vd < 0.97 0.26 < vd13 / vd < 0.33 1.47 < vd14 / vd < 1.61 0.32 < vd15 / vd < 0.46 0.78 < vd16 / vd < 0.85 1.31 < vd17 / vd < 1.64 Since refractive index and Abbe number are material specifications determined by the specific lens material, in this embodiment, the ninth cemented lens is made of H-LaK1; the tenth cemented lens is made of H-ZF3; the second lens is made of H-BaK4; the third lens is made of H-ZF59; the fourth lens is made of H-FK51; the fifth lens is made of H-ZF10; the sixth lens is made of H-BaK1; and the seventh lens is made of D-FK95.

[0044] Specifically, the air gap between the fourth and fifth cemented doublet lens groups is 11.86 mm, the air gap between the fifth and second lenses is 12.82 mm, the air gap between the second and third lenses is 5.13 mm, the air gap between the third and fourth lenses is 1.51 mm, the air gap between the fourth and fifth lenses is 1.5 mm, the air gap between the fifth and sixth lenses is 3.13 mm, and the air gap between the sixth and seventh lenses is 100.01 mm.

[0045] The above embodiments are merely illustrative of the technical concept and features of the present invention, intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and should not be construed as limiting the scope of protection of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description, and thus all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention.

Claims

1. A large-image-size 450mm fixed-focus lens, characterized in that, It includes a plane lens, a first lens group, and a second lens group arranged in sequence; The first lens group includes a first cemented doublet lens group, a second cemented doublet lens group, a first lens, a third cemented doublet lens group, and a fourth cemented doublet lens group arranged sequentially. The first cemented doublet lens group includes: The first cemented lens is a convex lens with positive refractive power; The second cemented lens is a concave lens with negative refractive power; The second cemented doublet lens group includes: Third cemented lens, a concave lens with negative refractive power; The fourth type of cemented lens is a convex lens with positive refractive power. The first lens is a convex lens with positive refractive power; The third cemented doublet lens group includes: The fifth cemented lens is a concave lens with negative refractive power; The sixth cemented lens is a convex lens with positive refractive power; The fourth cemented doublet lens group includes: The seventh cemented lens is a convex lens with positive refractive power; The eighth cemented lens is a concave lens with negative refractive power. The light transmission radius p of the plane lens satisfies: 18.6 < p < 20.7; The relationship between the light transmission radii of each lens in the first lens group and the planar lens is as follows: 0.8<pi / p<1.3, i=1, 2, 3, 4, 5, 6, 7, 8, 9; Where p1, p2, p3, p4, p5, p6, p7, p8, and p9 are the light transmission radii of the first cemented lens, the second cemented lens, the third cemented lens, the fourth cemented lens, the first lens, the fifth cemented lens, the sixth cemented lens, the seventh cemented lens, and the eighth cemented lens, respectively.

2. The 450mm fixed-focus lens with a large image sensor according to claim 1, characterized in that: The relationship satisfied by the radius of curvature of the first lens group is as follows: 0.004<|(Ri+Ri') / (Ri-Ri')|<5.426, i=1, 2, 3, 4, 5, 6, 7, 8, 9; Where Ri is the radius of curvature of the incident end of each lens in the first lens group, and Ri' is the radius of curvature of the exit end of each lens in the first lens group.

3. A large image sensor 450mm fixed-focus lens according to claim 2, characterized in that: The refractive index and Abbe number of the first lens group and the plane lens satisfy the following relationship: 0.9<ndi / nd<1.2, i=1, 2, 3, 4, 5, 6, 7, 8, 9; Wherein, nd is the refractive index of the plane lens; nd1, nd2, nd3, nd4, nd5, nd6, nd7, nd8, and nd9 are the refractive indices of the first cemented lens, the second cemented lens, the third cemented lens, the fourth cemented lens, the first lens, the fifth cemented lens, the sixth cemented lens, the seventh cemented lens, and the eighth cemented lens, respectively. 0.2<vdi / vd<1.1, i=1, 2, 3, 4, 5, 6, 7, 8, 9; Where vd is the Abbe number of the plane lens; vd1, vd2, vd3, vd4, vd5, vd6, vd7, vd8, and vd9 are the Abbe numbers of the first, second, third, fourth, first, fifth, sixth, seventh, and eighth cemented lenses, respectively.

4. The 450mm fixed-focus lens with a large image sensor according to claim 1, characterized in that: The second lens group includes, in sequence: The fifth cemented doublet lens group; The second lens is a concave lens with negative refractive power; The third lens is a convex lens with positive refractive power; The fourth lens is a convex lens with positive refractive power; The fifth lens is a concave lens with negative refractive power; The sixth lens is a convex lens with positive refractive power; The seventh lens is a convex lens with positive refractive power.

5. A large image sensor 450mm fixed focal length lens according to claim 4, characterized in that: The fifth cemented doublet lens group includes a ninth cemented lens and a tenth cemented lens. The ninth cemented lens is a concave lens with negative refractive power, and the tenth cemented lens is a convex lens with positive refractive power.

6. A large image sensor 450mm fixed focal length lens according to claim 5, characterized in that: The relationship between the light transmission radii of each lens in the second lens group and the planar lens is as follows: 1.1<pi / p<2.7, i=10, 11, 12, 13, 14, 15, 16, 17; Where p10, p11, p12, p13, p14, p15, p16, and p17 are the light transmission radii of the ninth cemented lens, the tenth cemented lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively.

7. A large image sensor 450mm fixed focal length lens according to claim 1, characterized in that: The relationship satisfied by the radius of curvature of the second lens group is as follows: 0.28<|(Ri+Ri') / (Ri-Ri')|<8.41; i=10, 11, 12, 13, 14, 15, 16, 17; Where Ri is the radius of curvature of the incident end of each lens in the second lens group, and Ri' is the radius of curvature of the exit end of each lens in the second lens group.

8. A large image sensor 450mm fixed focal length lens according to claim 1, characterized in that: The refractive index and Abbe number of the second lens group and the plane lens satisfy the following relationship: 0.8<ndi / nd<1.3, i=10, 11, 12, 13, 14, 15, 16, 17; nd10, nd11, nd12, nd13, nd14, nd15, nd16, and nd17 are the refractive indices of the ninth cemented lens, the tenth cemented lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively. 0.2<vdi / vd<1.7, i=10, 11, 12, 13, 14, 15, 16, 17; Where vd10, vd11, vd12, vd13, vd14, vd15, vd16, and vd17 are the Abbe numbers of the ninth cemented lens, the tenth cemented lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively.

9. A large image sensor 450mm fixed focal length lens according to claim 1, characterized in that: The thickness H of the plane lens satisfies: 3.8 < H < 4.1; In the first lens group, the central thickness of each lens and the plane lens satisfy the following relationship: 0.4<hi / H<2.2, i=1, 2, 3, 4, 5, 6, 7, 8, 9; Where h1, h2, h3, h4, h5, h6, h7, h8, and h9 are the center thicknesses of the first cemented lens, the second cemented lens, the third cemented lens, the fourth cemented lens, the first lens, the fifth cemented lens, the sixth cemented lens, the seventh cemented lens, and the eighth cemented lens, respectively.

10. A large image sensor 450mm fixed focal length lens according to claim 5, characterized in that: In the second lens group, the central thickness of each lens satisfies the following relationship with the planar lens: 0.6<hi / H<3.1, i=10, 11, 12, 13, 14, 15, 16, 17; h10, h11, h12, h13, h14, h15, h16, and h17 are the center thicknesses of the ninth cemented lens, the tenth cemented lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively.

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