A small-volume, low-distortion, large-area, high-resolution surveillance lens

Abstract

The present invention discloses a small-sized, low-distortion, large-target-area, and high-resolution surveillance lens. The optical system of the surveillance lens comprises a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, an aperture C, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, and an image plane IMG, arranged sequentially along the incident light path. The eighth lens L8 and the ninth lens L9 form a cemented lens group; the first lens L1 to the sixth lens L6 form a front lens group; and the seventh lens L7 to the tenth lens L10 form a rear lens group. The surveillance lens of the present invention features a small size, low distortion, a large-target-area, and high-resolution.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical lenses, and in particular relates to a surveillance lens with small volume, low distortion, large target surface and high resolution. Background Art

[0002] As an important component of the intelligent transportation system, surveillance cameras play a vital role and determine the accuracy of the information obtained.

[0003] Due to the particularity of the application environment, certain performance characteristics of surveillance lenses need to be different from those of ordinary lenses, such as smaller size, lower imaging distortion, larger imaging target area, and higher resolution.

[0004] The performance of existing surveillance lenses on the market has certain deficiencies. The market needs a surveillance lens with small size, low distortion, large target area and high resolution.

[0005] Therefore, developing a lens that can fully meet the above requirements has become an urgent task. Summary of the Invention

[0006] In view of the deficiencies of the prior art, the present invention provides a surveillance lens with small size, low distortion, large target area and high resolution.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a small-volume, low-distortion, large-target-area, high-resolution surveillance lens, wherein the optical system of the surveillance lens comprises a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, an aperture C, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, and an image plane IMG, which are sequentially arranged along an incident light path.

[0008] The first lens L1 is a biconvex positive lens or a meniscus positive lens with the convex surface facing the object;

[0009] The second lens L2 is a biconcave negative lens;

[0010] The third lens L3 is a biconcave negative lens;

[0011] The fourth lens L4 is a positive meniscus lens with its convex surface facing the image side;

[0012] The fifth lens L5 is a biconvex positive lens or a meniscus positive lens with the convex surface facing the image side;

[0013] The sixth lens L6 is a positive meniscus lens with its convex surface facing the object.

[0014] The seventh lens L7 is a biconvex positive lens;

[0015] The eighth lens L8 is a biconvex positive lens;

[0016] The ninth lens L9 is a biconcave negative lens;

[0017] The tenth lens L10 is a biconvex positive lens;

[0018] The eighth lens L8 and the ninth lens L9 form a cemented lens group; the first lens L1 to the sixth lens L6 form a front lens group; the seventh lens L7 to the tenth lens L10 form a rear lens group;

[0019] The monitoring lens satisfies the following condition: u1 / f|≤3.1, 1.2≤|f u2 / f|≤1.4,3.6≤TTL / f≤3.7,where f u1 Indicates the effective focal length of the front lens group; f u2 Indicates the effective focal length of the rear lens; f indicates the effective focal length of the surveillance lens; TTL indicates the total optical length of the surveillance lens.

[0020] As a specific implementation, the surveillance lens further satisfies the following conditional formula: 115≤(FOV×f) / IH≤116.5, where FOV represents the maximum field of view of the surveillance lens; IH represents the maximum image plane height of the surveillance lens; and f represents the effective focal length of the surveillance lens.

[0021] As a specific implementation, the monitoring lens also satisfies the following condition: SD max / TTL≤0.38, where SD max It indicates the clear aperture of the largest lens in the surveillance lens; TTL indicates the total optical length of the surveillance lens.

[0022] As a specific implementation, the monitoring lens further satisfies the following conditional formula: 0.01≤FOV / (D×TTL)≤0.02, wherein FOV represents the maximum field of view angle of the monitoring lens; D represents the aperture size of the monitoring lens head; and TTL represents the total optical length of the monitoring lens.

[0023] As a specific implementation manner, the monitoring lens further satisfies the following conditional formula: 5.9≤IH / FNO≤6.1, wherein IH represents the maximum image plane height of the monitoring lens; and FNO represents the aperture value of the monitoring lens.

[0024] As a specific implementation, the monitoring lens also satisfies the following condition: 13.5≤(f u1 +f u2 ) / IH≤14, where f u1 Indicates the effective focal length of the front lens group; f u2 Indicates the effective focal length of the rear lens group; IH indicates the maximum image height of the surveillance lens.

[0025] As a specific embodiment, the refractive index of the tenth lens L10 is N d10 , Abbe number is V D10 , N d10 、V D10 The following conditions are met respectively: Nd 10 ≤1.9; VD 10 ≥42.

[0026] As a specific embodiment, when the first lens L1 is a positive meniscus lens with its convex surface facing the object side; the second lens L2 is a biconcave negative lens; the third lens L3 is a biconcave negative lens; the fourth lens L4 is a positive meniscus lens with its convex surface facing the image side; the fifth lens L5 is a positive meniscus lens with its convex surface facing the image side; the sixth lens L6 is a positive meniscus lens with its convex surface facing the object side; the seventh lens L7 is a biconvex positive lens; the eighth lens L8 is a biconvex positive lens; the ninth lens L9 is a biconcave negative lens; and the tenth lens L10 is a biconvex positive lens, the air distance from the first lens L1 to the second lens L2 is 3.8674 mm; the air distance from the second lens L2 to the third lens L3 is 5.661 The air distance between the third lens L3 and the fourth lens L4 is 2.6113mm; the air distance between the fourth lens L4 and the fifth lens L5 is 0.1566mm; the air distance between the fifth lens L5 and the sixth lens L6 is 0.1518mm; the air distance between the sixth lens L6 and the aperture C is 8.1180mm; the air distance between the aperture C and the seventh lens L7 is 1.0928mm; the air distance between the seventh lens L7 and the eighth lens L8 is 0.2300mm; the air distance between the ninth lens L9 and the tenth lens L10 is 12.6847mm; and the air distance between the tenth lens L10 and the image plane IMG is 13.9076mm.

[0027] As a specific embodiment, when the first lens L1 is a biconvex positive lens; the second lens L2 is a biconcave negative lens; the third lens L3 is a biconcave negative lens; the fourth lens L4 is a meniscus positive lens with the convex surface facing the image side; the fifth lens L5 is a biconvex positive lens; the sixth lens L6 is a meniscus positive lens with the convex surface facing the object side; the seventh lens L7 is a biconvex positive lens; the eighth lens L8 is a biconvex positive lens; the ninth lens L9 is a biconcave negative lens; and the tenth lens L10 is a biconvex positive lens, the air distance from the first lens L1 to the second lens L2 is 4.0423 mm; the air distance from the second lens L2 to the third lens L3 is 5.4596 mm; and the air distance from the third lens L1 to the second lens L2 is 5.4596 mm. The air distance from the fourth lens L3 to the fourth lens L4 is 2.7359mm; the air distance from the fourth lens L4 to the fifth lens L5 is 0.1846mm; the air distance from the fifth lens L5 to the sixth lens L6 is 0.1573mm; the air distance from the sixth lens L6 to the aperture C is 8.1350mm; the air distance from the aperture C to the seventh lens L7 is 0.9864mm; the air distance from the seventh lens L7 to the eighth lens L8 is 0.1335mm; the air distance from the ninth lens L9 to the tenth lens L10 is 13.6734mm; and the air distance from the tenth lens L10 to the image plane IMG is 14.5877mm.

[0028] As a specific embodiment, when the first lens L1 is a positive meniscus lens with a convex surface facing the object side; the second lens L2 is a biconcave negative lens; the third lens L3 is a biconcave negative lens; the fourth lens L4 is a positive meniscus lens with a convex surface facing the image side; the fifth lens L5 is a positive meniscus lens with a convex surface facing the image side; the sixth lens L6 is a positive meniscus lens with a convex surface facing the object side; the seventh lens L7 is a biconvex positive lens; the eighth lens L8 is a biconvex positive lens; the ninth lens L9 is a biconcave negative lens; and the tenth lens L10 is a biconvex positive lens, the air distance from the first lens L1 to the second lens L2 is 3.4945 mm; the air distance from the second lens L2 to the third lens L3 is 6.404 The air distance between the third lens L3 and the fourth lens L4 is 2.7213 mm; the air distance between the fourth lens L4 and the fifth lens L5 is 0.1246 mm; the air distance between the fifth lens L5 and the sixth lens L6 is 0.1209 mm; the air distance between the sixth lens L6 and the aperture C is 7.9739 mm; the air distance between the aperture C and the seventh lens L7 is 0.8099 mm; the air distance between the seventh lens L7 and the eighth lens L8 is 0.1066 mm; the air distance between the ninth lens L9 and the tenth lens L10 is 12.6305 mm; and the air distance between the tenth lens L10 and the image plane IMG is 14.0655 mm.

[0029] Compared with the existing technology, the present invention provides a small-volume, low-distortion, large-target-area, high-resolution surveillance lens, which has the following beneficial effects:

[0030] 1) The present invention achieves the high resolution requirement of the optical system by rationally allocating the positions of lenses with different optical powers;

[0031] 2) By rationally controlling the ratio of optical power to total length of the optical system, that is, requiring 3.6 ≤ TTL / f ≤ 3.7, the low distortion requirement of the surveillance lens is achieved. In addition, by rationally combining lenses with different optical powers, that is, requiring 115 ≤ (FOV × f) / IH ≤ 116.5, the propagation light in the optical system is continuously corrected, thereby achieving the low distortion requirement.

[0032] 3) By requiring SD max / TTL≤0.38, 0.01≤FOV / (D×TTL)≤0.02, thus achieving miniaturization of surveillance lenses;

[0033] 4) Pass the requirements 5.9≤IH / FNO≤6.1, 13.5≤(f u1 +f u2 ) / IH≤14, thereby realizing a large target area of ​​the surveillance lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the optical path diagram of the small-volume, low-distortion, large-target-area, high-resolution surveillance lens in Example 1;

[0035] Figure 2 This is the MTF curve of the small-volume, low-distortion, large-target-area, high-resolution surveillance lens in the visible light band in Example 1;

[0036] Figure 3 This is a diagram of field curvature and distortion of the small-volume, low-distortion, large-target-area, high-resolution surveillance lens in Example 1;

[0037] Figure 4 This is the optical path diagram of the small-volume, low-distortion, large-target-area, high-resolution surveillance lens in Example 2;

[0038] Figure 5 This is the MTF curve of the small-volume, low-distortion, large-target-area, high-resolution surveillance lens in the visible light band in Example 2;

[0039] Figure 6 This is a diagram of field curvature and distortion of the small-volume, low-distortion, large-target-area, high-resolution surveillance lens in Example 2;

[0040] Figure 7 This is the optical path diagram of the small-volume, low-distortion, large-target-area, high-resolution surveillance lens in Example 3;

[0041] Figure 8 This is the MTF curve of the small-volume, low-distortion, large-target-area, high-resolution surveillance lens in the visible light band in Example 3;

[0042] Figure 9 This is a diagram of field curvature and distortion of the small-volume, low-distortion, large-target-area, and high-resolution surveillance lens in Example 3. DETAILED DESCRIPTION

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0044] A surveillance lens with a small volume, low distortion, large target surface and high resolution, wherein the optical system of the surveillance lens comprises a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, an aperture C, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10 and an image plane IMG, which are arranged in sequence along the incident light path. The first lens L1 is a biconvex positive lens or a meniscus positive lens with the convex surface facing the object side; the second lens L2 is a biconcave negative lens; the third lens L3 is a biconcave negative lens; the fourth lens L4 is a biconcave negative lens. Lens L4 is a positive meniscus lens with its convex surface facing the image side; the fifth lens L5 is a biconvex positive lens or a positive meniscus lens with its convex surface facing the image side; the sixth lens L6 is a positive meniscus lens with its convex surface facing the object side; the seventh lens L7 is a biconvex positive lens; the eighth lens L8 is a biconvex positive lens; the ninth lens L9 is a biconcave negative lens; and the tenth lens L10 is a biconvex positive lens. Among them, the eighth lens L8 and the ninth lens L9 form a cemented lens group; the first lens L1 to the sixth lens L6 constitute the front lens group; the seventh lens L7 to the tenth lens L10 constitute the rear lens group.

[0045] The first lens L1 is a biconvex positive lens or a meniscus positive lens with the convex surface facing the object side, which focuses the light entering the lens, thereby facilitating the acquisition of more light.

[0046] The second lens L2 is used to diverge the light collected by the first lens L1, perform aberration correction, and optimize the imaging performance of the lens group.

[0047] The third lens L3 is used to correct the secondary aberration of the light transmitted by the second lens L2.

[0048] The fourth lens L4 is used to collect the light corrected by the third lens L3 and smoothly transmit it to the subsequent optical system.

[0049] The fifth lens L5 is used to compress the light transmitted by the fourth lens L4, which is beneficial to reducing the size of the lens.

[0050] The sixth lens L6 is used to further compress the light transmitted by the fifth lens L5, which is beneficial to reducing the size of the lens.

[0051] The aperture C is placed between the sixth lens L6 and the seventh lens L7 to control the imaging quality and the performance of the optical system by limiting the propagation range and direction of the light beam.

[0052] The seventh lens L7 is placed after the aperture C and collects the light passing through the aperture C.

[0053] The eighth lens L8 and the ninth lens L9 form a cemented lens, which corrects the light collected by the seventh lens L7 and balances the distortion produced by the lens; at the same time, the eighth lens L8 and the ninth lens L9 use glass lenses to further enhance the stability of the lens group.

[0054] The tenth lens L10 can focus the light corrected by the cemented lens and present it to the imaging surface.

[0055] The lenses in the following embodiments are all made of glass with a normal refractive index.

[0056] Example 1

[0057] In the optical system of this example, the first lens L1 is a positive meniscus lens with its convex surface facing the object; the second lens L2 is a double-concave negative lens; the third lens L3 is a double-concave negative lens; the fourth lens L4 is a positive meniscus lens with its convex surface facing the image; the fifth lens L5 is a positive meniscus lens with its convex surface facing the image; the sixth lens L6 is a positive meniscus lens with its convex surface facing the object; the seventh lens L7 is a double-convex positive lens; the eighth lens L8 is a double-convex positive lens; the ninth lens L9 is a double-concave negative lens; the tenth lens L10 is a double-convex positive lens; the eighth lens L8 and the ninth lens L9 are cemented together. The optical path diagram of this surveillance lens is shown in Figure 1 shown.

[0058] See Table 1, which lists the relevant parameters of each lens in this example, including the radius of curvature, thickness, refractive index of the material, and Abbe number:

[0059] Table 1

[0060]

[0061] Infinity means infinity.

[0062] In this example, the air distance between the first lens L1 and the second lens L2 is 3.8674 mm; the air distance between the second lens L2 and the third lens L3 is 5.6613 mm; the air distance between the third lens L3 and the fourth lens L4 is 2.6113 mm; the air distance between the fourth lens L4 and the fifth lens L5 is 0.1566 mm; the air distance between the fifth lens L5 and the sixth lens L6 is 0.1518 mm; the air distance between the sixth lens L6 and the aperture C is 8.1180 mm; the air distance between the aperture C and the seventh lens L7 is 1.0928 mm; the air distance between the seventh lens L7 and the eighth lens L8 is 0.2300 mm; the air distance between the ninth lens L9 and the tenth lens L10 is 12.6847 mm; and the air distance between the tenth lens L10 and the image plane IMG is 13.9076 mm.

[0063] The technical indicators achieved by the optical system in this example are as follows:

[0064] 1) Maximum field of view of the surveillance camera: FOV = 35.6°;

[0065] 2) Effective focal length of the front lens group: f u1 =76.8900mm;

[0066] 3) Effective focal length of the rear lens group: f u2 =32.7100mm;

[0067] 4) Abbe number of the tenth lens L10: V d10 =42.73;

[0068] 5) Refractive index of the tenth lens L10: N d10 =1.83;

[0069] 6) Effective focal length of the surveillance lens: f = 26.2381 mm;

[0070] 7) Chief ray angle CRA of the surveillance camera: CRA = 0.4834°;

[0071] 8) Maximum image height of the surveillance lens: IH = 8.0941 mm;

[0072] 9) Aperture value FNO of the monitoring lens: FNO = 1.3409;

[0073] 10) The aperture size of the surveillance camera head: D = 35.4520mm;

[0074] 11) The clear aperture SD of the largest lens in the surveillance lens max :SD max =35.4520mm;

[0075] 12) Total optical length of the surveillance lens: TTL = 96.6083mm.

[0076] Then we get: TTL / f=3.6820;(FOV×f) / IH=115.4021;|f u1 / f|=2.9305;|f u2 / f|=1.2467; SD max / TTL=0.37;FOV / (D×TTL)=0.0104;IH / FNO=6.0363;(f u1 +f u2 ) / IH=13.5407.

[0077] Here, the low distortion requirement of the surveillance lens is achieved by reasonably controlling the ratio of the optical system's optical power to the total length, that is, requiring 3.6≤TTL / f≤3.7.

[0078] By rationally combining lenses of different optical powers, that is, requiring 115≤(FOV×f) / IH≤116.5, the propagation of light in the optical system is continuously corrected to achieve the low distortion requirement.

[0079] By request SD max / TTL≤0.38, 0.01≤FOV / (D×TTL)≤0.02, thereby realizing the miniaturization of the surveillance lens.

[0080] By the requirements of 5.9≤IH / FNO≤6.1, 13.5≤(f u1 +f u2 ) / IH≤14, thereby realizing a large target area of ​​the surveillance lens.

[0081] By reasonably selecting the refractive index and Abbe number of the tenth lens L10, that is, N d10 ≤1.9;V D10 ≥42, achieving the use of thermal drift-friendly glass, effectively improving the stability of the lens group.

[0082] The final imaging effect of the lens in this example is achieved through Figure 2 The MTF graph is used to evaluate the lens. The MTF curves under each field of view all decrease smoothly and have good consistency. As can be seen from the graph, the MTF value is not less than 0.5 at the spatial frequency of 70pl / mm in the edge field of view, which means that the lens has good imaging effect and resolution throughout the entire field of view. Figure 3 This is the field curvature distortion diagram of the lens of this embodiment. It can be seen that the distortion of this lens does not exceed 6%.

[0083] Example 2

[0084] In the optical system of this example, the first lens L1 is a biconvex positive lens; the second lens L2 is a biconcave negative lens; the third lens L3 is a biconcave negative lens; the fourth lens L4 is a meniscus positive lens with the convex side facing the image side; the fifth lens L5 is a biconvex positive lens; the sixth lens L6 is a meniscus positive lens with the convex side facing the object side; the seventh lens L7 is a biconvex positive lens; the eighth lens L8 is a biconvex positive lens; the ninth lens L9 is a biconcave negative lens, and the tenth lens L10 is a biconvex positive lens. The optical path diagram of this surveillance lens is shown in Figure 4 shown.

[0085] See Table 2, which lists the relevant parameters of each lens in this example, including the radius of curvature, thickness, refractive index of the material, and Abbe number:

[0086] Table 2

[0087]

[0088] Infinity means infinity.

[0089] In this example, the air distance between the first lens L1 and the second lens L2 is 4.0423 mm; the air distance between the second lens L2 and the third lens L3 is 5.4596 mm; the air distance between the third lens L3 and the fourth lens L4 is 2.7359 mm; the air distance between the fourth lens L4 and the fifth lens L5 is 0.1846 mm; the air distance between the fifth lens L5 and the sixth lens L6 is 0.1573 mm; the air distance between the sixth lens L6 and the aperture C is 8.1350 mm; the air distance between the aperture C and the seventh lens L7 is 0.9864 mm; the air distance between the seventh lens L7 and the eighth lens L8 is 0.1335 mm; the air distance between the ninth lens L9 and the tenth lens L10 is 13.6734 mm; and the air distance between the tenth lens L10 and the image plane IMG is 14.5877 mm.

[0090] The technical indicators achieved by the optical system in this example are as follows:

[0091] 1) Maximum field of view of the surveillance camera: FOV = 35.6°;

[0092] 2) Effective focal length of the front lens group: f u1 =77.1770mm;

[0093] 3) Effective focal length of the rear lens group: f u2 =34.8940mm;

[0094] 4) Abbe number of the tenth lens L10: V d10 =42.73;

[0095] 5) Refractive index of the tenth lens L10: N d10=1.83;

[0096] 6) Effective focal length of the surveillance lens: f = 26.4025mm;

[0097] 7) Chief ray angle CRA of the surveillance camera: CRA = 0.3159°;

[0098] 8) Maximum image height of the surveillance lens: IH = 8.0941 mm;

[0099] 9) Aperture value FNO of the monitoring lens: FNO = 1.3501;

[0100] 10) The aperture size of the surveillance camera head: D = 35.7250mm;

[0101] 11) The clear aperture SD of the largest lens in the surveillance lens max :SD max =35.7250mm;

[0102] 12) Total optical length of the surveillance lens: TTL = 96.6103 mm.

[0103] Then we get: TTL / f=3.6591;(FOV×f) / IH=116.1252;|f u1 / f|=2.9231;|f u2 / f|=1.3216; SD max / TTL=0.37;FOV / (D×TTL)=0.0103;IH / FNO=5.9952;(f u1 +f u2 ) / IH=13.8460.

[0104] The final imaging effect of the lens in this example is achieved through Figure 5-6 To evaluate, from Figure 5 As can be seen from the figure, the MTF curves under each field of view all decrease smoothly and have good consistency. As can be seen from the figure, at the edge of the field of view at a spatial frequency of 70pl / mm, the MTF value is greater than 0.56, which means that the lens has good imaging effect and resolution in the entire field of view. Figure 6 As can be seen from the field curvature distortion diagram, the distortion of this lens does not exceed 5%.

[0105] Example 3

[0106] In the optical system of this example, the first lens L1 is a positive meniscus lens with its convex surface facing the object; the second lens L2 is a double concave negative lens; the third lens L3 is a double concave negative lens; the fourth lens L4 is a positive meniscus lens with its convex surface facing the image; the fifth lens L5 is a positive meniscus lens with its convex surface facing the image; the sixth lens L6 is a positive meniscus lens with its convex surface facing the object; the seventh lens L7 is a double convex positive lens; the eighth lens L8 is a double convex positive lens; the ninth lens L9 is a double concave negative lens, and the tenth lens L10 is a double convex positive lens. The optical path diagram of this surveillance lens is shown in Figure 7 shown.

[0107] See Table 3, which lists the relevant parameters of each lens in this example, including the radius of curvature, thickness, refractive index of the material, and Abbe number:

[0108] Table 3

[0109]

[0110] Infinity means infinity.

[0111] In this example, the air distance between the first lens L1 and the second lens L2 is 3.4945 mm; the air distance between the second lens L2 and the third lens L3 is 6.4042 mm; the air distance between the third lens L3 and the fourth lens L4 is 2.7213 mm; the air distance between the fourth lens L4 and the fifth lens L5 is 0.1246 mm; the air distance between the fifth lens L5 and the sixth lens L6 is 0.1209 mm; the air distance between the sixth lens L6 and the aperture C is 7.9739 mm; the air distance between the aperture C and the seventh lens L7 is 0.8099 mm; the air distance between the seventh lens L7 and the eighth lens L8 is 0.1066 mm; the air distance between the ninth lens L9 and the tenth lens L10 is 12.6305 mm; and the air distance between the tenth lens L10 and the image plane IMG is 14.0655 mm.

[0112] The technical indicators achieved by the optical system in this example are as follows:

[0113] 1) Maximum field of view of the surveillance camera: FOV = 35.6°;

[0114] 2) Effective focal length of the front lens group: f u1 =78.5530mm;

[0115] 3) Effective focal length of the rear lens group: f u2 =32.9130mm;

[0116] 4) Abbe number of the tenth lens L10: V d10 =42.73;

[0117] 5) Refractive index of the tenth lens L10: N d10 =1.83;

[0118] 6) Effective focal length of the surveillance lens: f = 26.1759 mm;

[0119] 7) Chief ray angle CRA of the surveillance camera: CRA = 0.5502°;

[0120] 8) Maximum image height of the surveillance lens: IH = 8.0941 mm;

[0121] 9) Aperture value FNO of the monitoring lens: FNO = 1.3412;

[0122] 10) The aperture size of the surveillance camera head: D = 35.6440 mm;

[0123] 11) The clear aperture SD of the largest lens in the surveillance lens max :SD max =35.6440mm;

[0124] 12) Total optical length of the surveillance lens: TTL = 96.7289 mm.

[0125] Then we get: TTL / f = 3.6953; (FOV×f) / IH = 115.1286; |f u1 / f|=3.0010;|f u2 / f|=1.2574;SD max / TTL=0.37;FOV / (D×TTL)=0.0103;IH / FNO=6.0350;(f u1 +f u2 ) / IH=13.7713.

[0126] The final imaging effect of the lens in this example is achieved through Figure 8 To evaluate, from Figure 8 As can be seen from the figure, the MTF curves under each field of view all decrease smoothly and have good consistency. As can be seen from the figure, at the edge of the field of view at a spatial frequency of 70pl / mm, the MTF value is greater than 0.48, which means that the lens has good imaging effect and resolution in the entire field of view. Figure 9 As can be seen from the field curvature distortion diagram, the distortion of this lens does not exceed 6%.

[0127] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A small-volume, low-distortion, large-target-area, high-resolution surveillance lens, characterized by: The optical system of the monitoring lens is composed of a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, an aperture C, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10 and an image plane IMG, which are arranged in sequence along the incident light path. The first lens L1 is a biconvex positive lens or a meniscus positive lens with the convex surface facing the object; The second lens L2 is a biconcave negative lens; The third lens L3 is a biconcave negative lens; The fourth lens L4 is a positive meniscus lens with its convex surface facing the image side; The fifth lens L5 is a biconvex positive lens or a meniscus positive lens with the convex surface facing the image side; The sixth lens L6 is a positive meniscus lens with its convex surface facing the object. The seventh lens L7 is a biconvex positive lens; The eighth lens L8 is a biconvex positive lens; The ninth lens L9 is a biconcave negative lens; The tenth lens L10 is a biconvex positive lens; The eighth lens L8 and the ninth lens L9 form a cemented lens group; the first lens L1 to the sixth lens L6 form a front lens group; the seventh lens L7 to the tenth lens L10 form a rear lens group; The monitoring lens satisfies the following condition: 2.9231≤|f u1 / f|≤3.1, 1.2≤|f u2 / f|≤1.4,3.6≤TTL / f≤3.7,where f u1 Indicates the effective focal length of the front lens group; f u2 Indicates the effective focal length of the rear lens; f indicates the effective focal length of the surveillance lens; TTL indicates the total optical length of the surveillance lens.

2. The small-volume, low-distortion, large-target-area, high-resolution surveillance lens according to claim 1, characterized in that: The monitoring lens further satisfies the following conditional formula: 115≤(FOV×f) / IH≤116.5, wherein FOV represents the maximum field of view angle of the monitoring lens; IH represents the maximum image plane height of the monitoring lens; and f represents the effective focal length of the monitoring lens.

3. The small-volume, low-distortion, large-image-area, high-resolution surveillance lens according to claim 1, characterized in that: The monitoring lens also meets the following conditions: max / TTL≤0.38, where SD max It indicates the clear aperture of the largest lens in the surveillance lens; TTL indicates the total optical length of the surveillance lens.

4. The small-volume, low-distortion, large-target-area, high-resolution surveillance lens according to claim 1, characterized in that: The monitoring lens also satisfies the following conditional formula: 0.01≤FOV / (D×TTL)≤0.02, wherein FOV represents the maximum field of view angle of the monitoring lens; D represents the aperture size of the monitoring lens head; and TTL represents the total optical length of the monitoring lens.

5. The small-volume, low-distortion, large-image-area, high-resolution surveillance lens according to claim 1, characterized in that: The monitoring lens further satisfies the following conditional formula: 5.9≤IH / FNO≤6.1, wherein IH represents the maximum image plane height of the monitoring lens; and FNO represents the aperture value of the monitoring lens.

6. The small-volume, low-distortion, large-target-area, high-resolution surveillance lens according to claim 1, characterized in that: The monitoring lens also satisfies the following condition: 13.5≤(f u1 +f u2 ) / IH≤14, where f u1 Indicates the effective focal length of the front lens group; f u2 Indicates the effective focal length of the rear lens group; IH indicates the maximum image height of the surveillance lens.

7. The small-volume, low-distortion, large-target-area, high-resolution surveillance lens according to claim 1, characterized in that: The refractive index of the tenth lens L10 is N d10 , Abbe number is V D10 , N d10 、V D10 The following conditions are met respectively: Nd 10 ≤1.9; VD 10 ≥42.

8. The small-volume, low-distortion, large-image-area, high-resolution surveillance lens according to claim 1, characterized in that: When the first lens L1 is a positive meniscus lens with its convex surface facing the object side; the second lens L2 is a double concave negative lens; the third lens L3 is a double concave negative lens; the fourth lens L4 is a positive meniscus lens with its convex surface facing the image side; the fifth lens L5 is a positive meniscus lens with its convex surface facing the image side; the sixth lens L6 is a positive meniscus lens with its convex surface facing the object side; the seventh lens L7 is a double convex positive lens; the eighth lens L8 is a double convex positive lens; the ninth lens L9 is a double concave negative lens; and the tenth lens L10 is a double convex positive lens, the air distance from the first lens L1 to the second lens L2 is 3.8674 mm; the air distance from the second lens L2 to the third lens L3 is 5.6613 mm; and the air distance from the third lens L4 to the fourth lens L5 is 5.6613 mm. The air distance from lens L3 to the fourth lens L4 is 2.6113mm; the air distance from the fourth lens L4 to the fifth lens L5 is 0.1566mm; the air distance from the fifth lens L5 to the sixth lens L6 is 0.1518mm; the air distance from the sixth lens L6 to the aperture C is 8.1180mm; the air distance from the aperture C to the seventh lens L7 is 1.0928mm; the air distance from the seventh lens L7 to the eighth lens L8 is 0.2300mm; the air distance from the ninth lens L9 to the tenth lens L10 is 12.6847mm; and the air distance from the tenth lens L10 to the image plane IMG is 13.9076mm.

9. The small-volume, low-distortion, large-target-area, high-resolution surveillance lens according to claim 1, characterized in that: When the first lens L1 is a biconvex positive lens; the second lens L2 is a biconcave negative lens; the third lens L3 is a biconcave negative lens; the fourth lens L4 is a meniscus positive lens with the convex surface facing the image side; the fifth lens L5 is a biconvex positive lens; the sixth lens L6 is a meniscus positive lens with the convex surface facing the object side; the seventh lens L7 is a biconvex positive lens; the eighth lens L8 is a biconvex positive lens; the ninth lens L9 is a biconcave negative lens; and the tenth lens L10 is a biconvex positive lens, the air distance from the first lens L1 to the second lens L2 is 4.0423mm; the air distance from the second lens L2 to the third lens L3 is 5.4596mm; the air distance from the third lens L3 to the fourth lens L4 is 5.4596mm. The air distance of lens L4 is 2.7359mm; the air distance from the fourth lens L4 to the fifth lens L5 is 0.1846mm; the air distance from the fifth lens L5 to the sixth lens L6 is 0.1573mm; the air distance from the sixth lens L6 to the aperture C is 8.1350mm; the air distance from the aperture C to the seventh lens L7 is 0.9864mm; the air distance from the seventh lens L7 to the eighth lens L8 is 0.1335mm; the air distance from the ninth lens L9 to the tenth lens L10 is 13.6734mm; and the air distance from the tenth lens L10 to the image plane IMG is 14.5877mm.

10. The small-volume, low-distortion, large-image-area, high-resolution surveillance lens according to claim 1, characterized in that: When the first lens L1 is a positive meniscus lens with its convex surface facing the object side; the second lens L2 is a double concave negative lens; the third lens L3 is a double concave negative lens; the fourth lens L4 is a positive meniscus lens with its convex surface facing the image side; the fifth lens L5 is a positive meniscus lens with its convex surface facing the image side; the sixth lens L6 is a positive meniscus lens with its convex surface facing the object side; the seventh lens L7 is a double convex positive lens; the eighth lens L8 is a double convex positive lens; the ninth lens L9 is a double concave negative lens; and the tenth lens L10 is a double convex positive lens, the air distance from the first lens L1 to the second lens L2 is 3.4945 mm; the air distance from the second lens L2 to the third lens L3 is 6.4042 mm; and the third lens L4 is a positive meniscus lens with its convex surface facing the image side. The air distance between lens L3 and the fourth lens L4 is 2.7213mm; the air distance between the fourth lens L4 and the fifth lens L5 is 0.1246mm; the air distance between the fifth lens L5 and the sixth lens L6 is 0.1209mm; the air distance between the sixth lens L6 and the aperture C is 7.9739mm; the air distance between the aperture C and the seventh lens L7 is 0.8099mm; the air distance between the seventh lens L7 and the eighth lens L8 is 0.1066mm; the air distance between the ninth lens L9 and the tenth lens L10 is 12.6305mm; and the air distance between the tenth lens L10 and the image plane IMG is 14.0655mm.

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