Lens system

Abstract

The utility model discloses a lens system which comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged from an object plane to an image plane along an optical axis. The focal power of the first lens is negative, the focal power of the second lens is positive, the focal power of the third lens is positive, the focal power of the fourth lens is negative, and the focal power of the fifth lens is positive; the distance from the image side surface of the first lens to the object side surface of the second lens on the optical axis is AT12, the distance from the image side surface of the second lens to the object side surface of the third lens on the optical axis is AT23, and the total optical length of the lens system is TTL; wherein, the result is 0.085 lt; (AT12 + AT23) / TTLlt; and 0.185%. According to the technical scheme, the lens system comprises the five lenses, the focal power matching mode of the five lenses is reasonably set, the number of the lenses is reasonable, and the structure is simple and compact; the focal power and the position of each lens are reasonable, so that a good imaging effect can be realized; furthermore, the air gaps among the lenses are reasonably arranged, so that the miniaturization design of the lens system is facilitated.

Description

Technical Field

[0001] The embodiments of the utility model relate to the technical field of optical devices, and in particular to a lens system. Background Art

[0002] As people's safety awareness continues to improve, optical lenses play an increasingly important role in machine vision, artificial intelligence, criminal investigation monitoring, unmanned driving, etc., which have promoted the development of the security monitoring field.

[0003] In recent years, many series of surveillance lenses have been launched for different purposes and environments. Among them, lenses with an equivalent focal length of 2.8mm have a relatively large market share due to their unique performance. Currently, the total optical length of this type of lens on the market is generally greater than 22mm, which cannot meet specific application scenarios requiring short total length and small size. Utility Model Content

[0004] The utility model provides a lens system, which realizes a simple and compact structure by reasonably setting the lens composition, optical power distribution and air gap between lenses, and is conducive to the design of a miniaturized lens system.

[0005] The embodiment of the utility model provides a lens system, comprising a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence from the object plane to the image plane along the optical axis;

[0006] The optical power of the first lens is negative, the optical power of the second lens is positive, the optical power of the third lens is positive, the optical power of the fourth lens is negative, and the optical power of the fifth lens is positive;

[0007] The distance on the optical axis from the image side of the first lens to the object side of the second lens is AT12, the distance on the optical axis from the image side of the second lens to the object side of the third lens is AT23, and the total optical length of the lens system is TTL;

[0008] Among them, 0.085<(AT12+AT23) / TTL<0.185.

[0009] Optionally, the focal power of the first lens is Φ1, the focal power of the second lens is Φ2, the focal power of the third lens is Φ3, the focal power of the fourth lens is Φ4, the focal power of the fifth lens is Φ5, and the focal power of the lens system is Φ;

[0010] Among them, -0.85≤Φ1 / Φ≤-0.65, 0.18≤Φ2 / Φ≤0.32, 0.38≤Φ3 / Φ≤0.52,

[0011] -0.95≤Φ4 / Φ≤-0.45, 0.685≤Φ5 / Φ≤0.985.

[0012] Optionally, the refractive index of the third lens is ND3 and the Abbe number is VD3;

[0013] Among them, 1.41≤ND3≤1.51, 85.50≤VD3≤98.50.

[0014] Optionally, the distance on the optical axis from the object side surface of the first lens to the image side surface of the fifth lens is DL, and the total optical length of the lens system is TTL;

[0015] Among them, 0.645 <DL / TTL<0.745。

[0016] Optionally, the image height of the lens system is IC, the total optical length of the lens system is TTL, and the entrance pupil diameter of the lens system is EPD;

[0017] Among them, 0.355≤IC / TTL≤0.425, 1.85≤IC / EPD≤2.55.

[0018] Optionally, the optical back focus of the lens system is BFL, and the total optical length of the lens system is TTL;

[0019] Among them, 0.265≤BFL / TTL≤0.365.

[0020] Optionally, the first lens is a plastic aspheric lens, the second lens is a plastic aspheric lens, the third lens is a glass spherical lens, the fourth lens is a plastic aspheric lens, and the fifth lens is a plastic aspheric lens.

[0021] Optionally, the first lens includes a first object-side surface close to the object plane and a first image-side surface close to the image plane, the first object-side surface is convex, the first image-side surface is concave, and the first lens is a meniscus lens;

[0022] The second lens includes a second object-side surface close to the object plane and a second image-side surface close to the image plane, the second object-side surface is concave, the first image-side surface is convex, and the second lens is a meniscus lens;

[0023] The third lens comprises a third object-side surface close to the object plane and a third image-side surface close to the image plane, the third object-side surface is a convex surface, and the first image-side surface is a convex surface;

[0024] The fourth lens comprises a fourth object-side surface close to the object plane and a fourth image-side surface close to the image plane, the fourth object-side surface is convex, and the fourth image-side surface is concave;

[0025] The fifth lens includes a fifth object-side surface close to the object plane and a fifth image-side surface close to the image plane. The fifth object-side surface is a convex surface, and the fifth image-side surface is a convex surface.

[0026] Optionally, the lens system further includes an aperture stop and a filter;

[0027] The aperture stop is arranged in the optical path between the second lens and the third lens, or the aperture stop is arranged in the optical path between the third lens and the fourth lens;

[0028] The filter is arranged in the optical path between the fifth lens and the image plane.

[0029] Optionally, the aperture of the lens system is FNO, the total focal length is f, the field of view angle is FOV, and the total optical length is TTL;

[0030] Among them, 1.55≤FNO≤1.75; 2.90≤f≤3.45; FOV≥130°; TTL≤18.0mm.

[0031] The lens system provided by the embodiment of the present invention includes five lenses with optical power, namely the first lens, the second lens, the third lens, the fourth lens and the fifth lens. The number of lenses is reasonable and the structure is simple and compact. In addition, the optical power of the first lens and the fourth lens is negative, and the optical power of the second lens, the third lens and the fifth lens is positive. By reasonably setting the optical power matching method of each lens in the lens system, it is beneficial to achieve a larger field of view angle of the lens system and timely correct the aberration, thereby improving the imaging resolution of the lens system. Furthermore, the air gap AT12 between the first lens and the second lens, the air gap AT23 between the second lens and the third lens and the total optical length TTL of the lens system meet 0.085<(AT12+AT23) / TTL<0.185, thereby making the arrangement of each lens more reasonable and facilitating the miniaturization design of the lens system.

[0032] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 This is a structural diagram of a lens system provided in Example 1 of the present utility model;

[0035] Figure 2 This is a schematic diagram of a spherical aberration curve of a lens system provided in Example 1 of the present utility model;

[0036] Figure 3 This is a schematic diagram of a light fan curve of a lens system provided in the first embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram of a field curvature distortion curve of a lens system provided in the first embodiment of the present invention;

[0038] Figure 5 This is a structural diagram of a lens system provided in Example 2 of the present utility model;

[0039] Figure 6 This is a schematic diagram of a spherical aberration curve of a lens system provided in the second embodiment of the present invention;

[0040] Figure 7 This is a schematic diagram of a light fan curve of a lens system provided in the second embodiment of the present invention;

[0041] Figure 8 This is a schematic diagram of a field curvature distortion curve of a lens system provided in the second embodiment of the present invention;

[0042] Figure 9 This is a structural diagram of a lens system provided in the third embodiment of the present invention;

[0043] Figure 10 This is a schematic diagram of a spherical aberration curve of a lens system provided in the third embodiment of the present invention;

[0044] Figure 11 This is a schematic diagram of a light fan curve of a lens system provided in the third embodiment of the present invention;

[0045] Figure 12 This is a schematic diagram of a field curvature distortion curve of a lens system provided in the third embodiment of the present invention;

[0046] Figure 13 This is a structural diagram of a lens system provided by the fourth embodiment of the present utility model;

[0047] Figure 14 This is a schematic diagram of a spherical aberration curve of a lens system provided by the fourth embodiment of the present utility model;

[0048] Figure 15 This is a schematic diagram of a light fan curve of a lens system provided by the fourth embodiment of the present utility model;

[0049] Figure 16 This is a schematic diagram of a field curvature distortion curve of a lens system provided by the fourth embodiment of the present utility model;

[0050] Figure 17 This is a structural diagram of a lens system provided by the fifth embodiment of the present utility model;

[0051] Figure 18 This is a schematic diagram of a spherical aberration curve of a lens system provided in a fifth embodiment of the present invention;

[0052] Figure 19 This is a schematic diagram of a light fan curve of a lens system provided by the fifth embodiment of the present utility model;

[0053] Figure 20 This is a schematic diagram of a field curvature distortion curve of a lens system provided in Example 5 of the present utility model. DETAILED DESCRIPTION

[0054] In order to help those skilled in the art better understand the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described 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 should fall within the scope of protection of the present invention.

[0055] Example 1

[0056] Figure 1 This is a structural diagram of a lens system provided in the first embodiment of the present invention. Figure 1As shown, the lens system provided by Example 1 of the present invention includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, and a fifth lens 105, which are arranged in sequence along the optical axis from the object plane to the image plane. The first lens 101 has a negative optical power, the second lens 102 has a positive optical power, the third lens 103 has a positive optical power, the fourth lens 104 has a negative optical power, and the fifth lens 105 has a positive optical power. The distance on the optical axis from the image side surface of the first lens 101 to the object side surface of the second lens 102 is AT12, the distance on the optical axis from the image side surface of the second lens 102 to the object side surface of the third lens 103 is AT23, and the total optical length of the lens system is TTL. Wherein, 0.085<(AT12+AT23) / TTL<0.185.

[0057] Specifically, the lens system provided by the embodiment of the present invention includes five lenses, namely a first lens 101, a second lens 102, a third lens 103, a fourth lens 104 and a fifth lens 105. The arrangement of the five lenses ensures a reasonable number of lenses, a simple and compact structure, and is conducive to achieving the miniaturization requirement of the lens system.

[0058] Furthermore, the focal length is equal to the difference between the convergence degree of the image plane light beam and the convergence degree of the object plane light beam, which characterizes the ability of the optical system to deflect light. The larger the absolute value of the focal length, the stronger the ability to bend light, and the smaller the absolute value of the focal length, the weaker the ability to bend light. When the focal length is a positive number, the refraction of light is convergent; when the focal length is a negative number, the refraction of light is divergent. The focal length can be applied to characterize a certain refractive surface of a lens (i.e., a surface of a lens), can be applied to characterize a certain lens, and can also be applied to characterize a system formed by multiple lenses (i.e., a lens group). In the embodiment of the present invention, the first lens 101 is a negative focal length lens. The first lens 101 is the first lens group in the lens system to adjust the incident light. The setting of its negative focal length can effectively deflect the incident light at a large angle, ensure that more light enters the optical system, and thus effectively increase the field of view of the lens system. Specifically, the field of view angle of the lens system in the embodiment of the present invention is FOV, and FOV≥130°, which meets the large field of view requirement and improves the imaging quality. Furthermore, the second lens 102 and the third lens 103 are both positive optical focal length lenses, so that the second lens 102 and the third lens 103 can timely correct the larger aberrations generated by the first lens 101, especially can have a significant correction effect on the edge aberrations of the lens system, thereby improving the imaging resolution of the optical system. Furthermore, the optical focal length of the fourth lens 104 is negative, and the optical focal length of the fifth lens 105 is positive. The optical focal length of the latter lens in the optical path is different from the optical focal length of the previous lens, which is conducive to the correction of aberrations. In summary, by reasonably setting the optical focal length matching method of the five lenses, it is conducive to achieving a lens system with a large viewing angle and good imaging quality.

[0059] Furthermore, the distance on the optical axis from the image side surface of the first lens 101 to the object side surface of the second lens 102 is AT12, that is, the air gap between the first lens 101 and the second lens 102 is AT12; the distance on the optical axis from the image side surface of the second lens 102 to the object side surface of the third lens 103 is AT23, that is, the air gap between the second lens 102 and the third lens 103 is AT23; wherein, the air gap AT12 between the first lens 101 and the second lens 102, the air gap AT23 between the second lens 102 and the third lens 103, and the total optical length TTL of the lens system satisfy 0.085 < (AT12 + AT23) / TTL < 0.185, thereby making the arrangement of each lens more reasonable and more conducive to the miniaturization design of the optical lens. Specifically, the optical assembly of the lens system in the embodiment of the utility model is TTL, TTL ≤ 18.0 mm, meeting the requirements of miniaturization lens configuration.

[0060] In summary, in the embodiment of the present invention, by setting the lens system to include five lenses with optical focal lengths, the number of lenses is reasonable, and the structure is simple and compact. In addition, the optical focal lengths of the first lens and the fourth lens are negative, and the optical focal lengths of the second lens, the third lens, and the fifth lens are positive. By reasonably setting the optical focal length matching method of each lens in the lens system, it is beneficial to achieve a larger field of view angle of the lens system and timely correction of aberrations, thereby improving the imaging resolution of the lens system. Furthermore, the air gap AT12 between the first lens and the second lens, the air gap AT23 between the second lens and the third lens, and the total optical length TTL of the lens system satisfy 0.085<(AT12+AT23) / TTL.

[0061] <0.185, which makes the arrangement of each lens more reasonable and is conducive to the miniaturization design of the lens system.

[0062] Further, such as Figure 1 As shown, the lens system provided by the embodiment of the present invention may further include an aperture stop 106 and a filter 107. The aperture stop 106 is arranged in the optical path between the second lens 102 and the third lens 103, or the aperture stop 106 is arranged in the optical path between the third lens 103 and the fourth lens 104; the filter 107 is arranged in the optical path between the fifth lens 105 and the image plane.

[0063] Specifically, the aperture stop 106 is disposed in the optical path of the lens system. This can effectively reduce the aperture size of the lens in front of the aperture stop 106 and reduce the weight of the lens. On the other hand, it is conducive to reducing the aperture FNO value and achieving a large aperture. Specifically, in an embodiment of the present invention, the aperture of the lens system is FNO, where 1.55≤FNO≤1.75, which meets the setting requirements of a large aperture. Furthermore, in an embodiment of the present invention, the aperture stop 106 is disposed in the optical path between the second lens 102 and the third lens 103, or the aperture stop 106 is disposed in the optical path between the third lens 103 and the fourth lens 104. The aperture stop 106 has a variety of different settings and can be applied to different usage scenarios.

[0064] For further reference, Figure 1As shown, the lens system provided by the embodiment of the present invention may further include a filter 107, which is arranged in the optical path between the fifth lens 105 and the image plane to filter out stray light and improve the imaging effect. Specifically, the filter 107 may be a red filter. Furthermore, the lens system provided by the embodiment of the present invention may further include a protective glass and an image acquisition element. The protective glass may be arranged on the image side of the filter, and the image acquisition element may be arranged on the image side of the protective glass. The lens system is protected by the protective glass, and the image is acquired by the image acquisition element, thereby realizing the normal imaging function of the lens system.

[0065] Based on the above embodiment, the optical power of the first lens 101 is Φ1, the optical power of the second lens 102 is Φ2, the optical power of the third lens 103 is Φ3, the optical power of the fourth lens 104 is Φ4, and the optical power of the fifth lens 105 is Φ5, and the optical power of the lens system is Φ; wherein, -0.85≤Φ1 / Φ≤-0.65, 0.18≤Φ2 / Φ≤0.32, 0.38≤Φ3 / Φ≤0.52, -0.95≤Φ4 / Φ≤-0.45, and 0.685≤Φ5 / Φ≤0.985.

[0066] Specifically, the focal power Φ1 of the first lens 101 and the focal power Φ of the lens system are set to satisfy -0.85≤Φ1 / Φ≤-0.65, so that the object-side light is smoothly input into the lens system, reducing the proportion of high-order aberrations. At the same time, by reasonably controlling the value of Φ1 / Φ, the head diameter of the lens system can be reduced, and the diameter of the lens system can be miniaturized.

[0067] The focal power Φ2 of the second lens 102 and the focal power Φ of the lens system are set to satisfy 0.18≤Φ2 / Φ≤0.32, which can diverge the light at a relatively gentle deflection angle, increase the entrance pupil diameter, and facilitate the realization of the large aperture characteristic of the system.

[0068] The focal power Φ3 of the third lens 103 and the focal power Φ of the lens system are set to satisfy 0.38≤Φ3 / Φ≤0.52, so that the light of each field of view can be emitted at a reasonable angle, which can effectively reduce the aberration related to the field of view and the tolerance sensitivity of the lens.

[0069] The focal power Φ4 of the fourth lens 104 and the focal power Φ of the lens system are set to satisfy -0.95≤Φ4 / Φ≤-0.45, and the focal power Φ5 of the fifth lens 105 and the focal power Φ of the lens system are set to satisfy 0.685≤Φ5 / Φ≤0.985. This can make the light deflection angle transition smooth, while ensuring the imaging quality and also making the system have a smaller tolerance sensitivity.

[0070] On the basis of the above embodiments, the refractive index of the third lens 103 is ND3, and the Abbe number is VD3; where 1.41 ≤ ND3 ≤ 1.51 and 85.50 ≤ VD3 ≤ 98.50. Controlling the refractive index and Abbe number of the third lens 103 within this range is beneficial to balancing aberrations, controlling the ray height, and facilitating the miniaturization of the lens.

[0071] On the basis of the above embodiments, the distance from the object side surface of the first lens 101 to the image side surface of the fifth lens 105 on the optical axis is DL, and the overall optical length of the lens system is TTL; where

[0072] 0.645 < DL / TTL < 0.745. Controlling the distance DL from the object side surface of the first lens 101 to the image side surface of the fifth lens 105 on the optical axis and the overall optical length TTL of the lens system to satisfy 0.645 < DL / TTL < 0.745 can make the arrangement of each lens more reasonable and is more conducive to the miniaturization design of the optical lens.

[0073] On the basis of the above embodiments, the image height of the lens system is IC, the overall optical length of the lens system is TTL, and the entrance pupil diameter of the lens system is EPD; where 0.355 ≤ IC / TTL ≤ 0.425 and 1.85 ≤ IC / EPD ≤ 2.55.

[0074] Specifically, when the image height IC of the lens system and the overall optical length TTL of the lens system satisfy 0.355 ≤ IC / TTL ≤ 0.425, it indicates that the lens system has a larger image plane and a smaller volume, can ensure that the optical system has better imaging quality and a clearer picture, and has a smaller volume at the same time.

[0075] When the image height IC of the lens system and the entrance pupil diameter EPD of the lens system satisfy 1.85 ≤ IC / EPD ≤ 2.55, it can enable the lens system to control the entrance pupil diameter of the lens while satisfying high-quality imaging, ensure that the imaging system has a larger light transmission amount under the same focal length, and thus has a larger aperture.

[0076] On the basis of the above embodiments, the back focal length of the lens system is BFL, and the overall optical length of the lens system is TTL; where 0.265 ≤ BFL / TTL ≤ 0.365, which can ensure that there is enough installation space for the imaging sensor and the flat filter.

[0077] On the basis of the above embodiments, the first lens 101 is a plastic aspherical lens, the second lens 102 is a plastic aspherical lens, the third lens 103 is a glass spherical lens, the fourth lens 104 is a plastic aspherical lens, and the fifth lens 105 is a plastic aspherical lens.

[0078] Specifically, aspheric lenses are characterized by a continuously varying curvature from the center to the periphery of the lens. Unlike spherical lenses, which have a constant curvature from the center to the periphery, aspheric lenses have a better curvature radius characteristic, with the advantages of improving distortion and astigmatism. By configuring the first lens 101, the second lens 102, the fourth lens 104, and the fifth lens 105 as aspheric lenses, aberrations that occur during imaging can be minimized, thereby improving the imaging quality of the lens. Furthermore, the aspheric lenses can be plastic aspheric lenses, which helps simplify the manufacturing process and reduce the cost of aspheric lenses.

[0079] Spherical lenses are characterized by a constant curvature from the center to the periphery, ensuring simple lens configuration. Furthermore, because glass lenses have a low coefficient of thermal expansion and excellent stability, third lens 103 can be configured as a glass spherical lens. Glass spherical lenses offer greater thermal stability, ensuring good resolution over a wide temperature range when handling a wide range of optical powers. Furthermore, compared to plastic aspherical lenses, glass materials offer a wider range of material options, with relatively free choices of refractive index and Abbe constant. This allows for a certain degree of control over higher-order aberrations and chromatic aberrations, meeting the demands of use under complex conditions.

[0080] In the lens system provided by the embodiment of the present invention, a mixed combination of glass spherical lenses and plastic aspherical lenses can be used, thereby effectively controlling the cost of the lens system while ensuring the optical performance of the lens system; at the same time, the materials of the lenses can compensate for each other, ensuring normal use in high and low temperature environments.

[0081] Based on the above embodiment, the first lens 101 includes a first object-side surface close to the object plane and a first image-side surface close to the image plane, the first object-side surface is convex, the first image-side surface is concave, and the first lens is a meniscus lens; the second lens 102 includes a second object-side surface close to the object plane and a second image-side surface close to the image plane, the second object-side surface is concave, the first image-side surface is convex, and the second lens is a meniscus lens; the third lens 103 includes a third object-side surface close to the object plane and a third image-side surface close to the image plane, the third object-side surface is convex, and the first image-side surface is convex; the fourth lens 104 includes a fourth object-side surface close to the object plane and a fourth image-side surface close to the image plane, the fourth object-side surface is convex, and the fourth image-side surface is concave; the fifth lens 105 includes a fifth object-side surface close to the object plane and a fifth image-side surface close to the image plane, the fifth object-side surface is convex, and the fifth image-side surface is convex.

[0082] Furthermore, the object-side surface of the lens can be understood as the surface of the lens close to the object plane, and the image-side surface of the lens can be understood as the surface of the lens close to the image plane. Specifically, the object-side surface of the first lens 101 is convex, and the image-side surface is concave. This can be understood as the object-side surface of the first lens 101 being convex toward the object plane near the optical axis, and the image-side surface being concave toward the image plane near the optical axis, that is, the first lens 101 is a lens with a convex-concave structure. Furthermore, the first lens 101 can be a meniscus-shaped negative lens, which can focus as much light as possible from a large field of view into the system, thereby improving the field of view of the optical system.

[0083] The object-side surface of the second lens 102 is concave, and the image-side surface is convex. This can be understood as the object-side surface of the second lens 102 being concave toward the object plane near the optical axis, and the image-side surface being convex toward the image plane near the optical axis, that is, the second lens 102 is a lens with a concave-convex structure. The second lens 102 is designed as a concave-convex lens, which can effectively control the trajectory of light, reduce the field curvature and spherical aberration of the optical system, and improve the image quality of the optical system. Furthermore, the second lens 102 and the first lens 101 can be arranged symmetrically, and this layout is conducive to improving the image quality of the system. In addition, the second lens 102 is a meniscus lens, specifically a thick meniscus lens, that is, the second lens 102 is relatively thick. This design can effectively correct aberrations such as spherical aberration and field curvature in the system.

[0084] The object-side surface and image-side surface of the third lens element 103 are convex. This means that the object-side surface of the third lens element 103 is convex toward the object plane near the optical axis, and the image-side surface is convex toward the image plane near the optical axis. In other words, the third lens element 103 has a biconvex structure. The biconvex shape of the third lens element 103 effectively reduces the tolerance sensitivity of the lens element.

[0085] The object-side surface of the fourth lens 104 is convex, and the image-side surface is concave. This means that the object-side surface of the fourth lens 104 is convex toward the object plane near the optical axis, while the image-side surface is concave toward the image plane near the optical axis. In other words, the fourth lens 104 has a convex-concave structure. The object-side surface of the fifth lens 105 is convex, and the image-side surface is convex. This means that the object-side surface of the fifth lens 105 is convex toward the object plane near the optical axis, while the image-side surface is convex toward the image plane near the optical axis. In other words, the fifth lens 105 has a biconvex structure. The convex-concave negative design of the fourth lens 104, combined with the biconvex positive design of the fifth lens 105, effectively controls the trajectory of light, shortens the total optical length, and makes the system more compact. It also allows light to reach the image plane at a smaller angle, ensuring that the system has a reasonable chief ray angle (CRA) to match the CRA curve requirements of the subsequent chip.

[0086] On the basis of the above embodiments, the embodiment of the present invention provides a total focal length of the lens system of f, 2.90≤f≤3.45. Within this focal length range, clear imaging can be guaranteed.

[0087] As a feasible implementation method, the specific parameters of the lens system are described below.

[0088] Table 1 Optical design values of the lens system in Example 1

[0089] Conditional expression Example 1 Lower limit Upper limit <![CDATA[Φ1 / Φ]]> -0.713 -0.850 -0.650 <![CDATA[Φ2 / Φ]]> 0.210 0.180 0.320 <![CDATA[Φ3 / Φ]]> 0.448 0.380 0.520 ND3 1.457 1.410 1.510 VD3 90.27 85.50 98.50 <![CDATA[Φ4 / Φ]]> -0.653 -0.950 -0.450 <![CDATA[Φ5 / Φ]]> 0.750 0.685 0.985 DL / TTL 0.701 0.645 0.745 (AT12+AT23) / TTL 0.135 0.085 0.185 IC / TTL 0.372 0.355 0.425 IC / EPD 2.079 1.850 2.550 BFL / TTL 0.299 0.265 0.365

[0090] Table 2 Design values of optical physical parameters of a lens system

[0091] Surface number Surface type Curvature radius (mm) Thickness (mm) (nd) / (vd) Semi-diameter (mm) k value 1 even aspherical surface 39.041 0.880 1.535 / 55.71 3.87 -50.737 2 even aspherical surface 2.242 2.330 2.16 -0.202 3 even aspherical surface -10.801 3.386 1.640 / 23.50 1.80 28.807 4 even aspherical surface -5.771 -0.037 2.25 -0.748 5 STO INF 0.105 2.23 6 Standard surface 8.475 2.575 1.457 / 90.27 3.20 7 Standard surface -4.767 0.076 3.20 8 even aspherical surface 5.487 0.806 1.661 / 20.38 2.23 -16.527 9 even aspherical surface 1.923 0.173 2.48 -3.370 10 even aspherical surface 3.116 2.153 1.535 / 55.71 2.54 -0.843 11 even aspherical surface -6.431 2.075 2.71 -3.783 12 Standard surface INF 0.210 1.517 / 64.20 2.98 13 Standard surface INF 2.541 3.00 14 Standard surface INF 0.390 1.517 / 64.20 3.27 15 Standard surface INF 0.100 3.30 IMA Standard surface INF 3.31

[0092] The surface numbers in Table 2 are numbered according to the order of the surfaces of each lens. "1" represents the object-side surface of the first lens, "2" represents the image-side surface of the first lens, and so on. "STO" represents the aperture of the lens; the radius of curvature represents the degree of curvature of the lens surface. A positive value represents that the surface is curved toward the image side, and a negative value represents that the surface is curved toward the object side. "INF" represents that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance from the current surface to the next surface. nd represents the refractive index, which represents the light-reflecting ability of the material between the current surface and the next surface. A blank represents that the current position is air with a refractive index of 1. vd represents the Abbe number, which represents the dispersion characteristics of the material between the current surface and the next surface. The semi-aperture represents half the aperture size of the current surface. The k value represents the numerical value of the conic coefficient of the aspheric surface.

[0093] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following expression method:

[0094]

[0095] Wherein, z is the axial sagittal height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the radius of curvature; k is the fitting cone coefficient; AG is the coefficient of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspheric polynomial.

[0096] Table 3 Aspheric coefficients of a lens system

[0097]

[0098] Among them, "-5.439867E-04" means -5.439867*10 -4 , and the remaining coefficients all use this representation method.

[0099] Based on the above parameter limitations, the optical parameters that can be achieved by the lens system in the first embodiment of the present invention are as follows:

[0100] Focal length f: 3.18mm;

[0101] F#: 1.65;

[0102] Field of view: FOV = 132.5°;

[0103] Total optical length: TTL = 17.76mm.

[0104] Further, Figure 2 This is a schematic diagram of the spherical aberration curve of a lens system provided by the first embodiment of the present invention. The vertical direction represents the normalized aperture, with 0 representing the optical axis and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of imaging of the system (436nm, 486nm, 546nm, 587nm, 656nm, and 850nm, respectively). Figure 2 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.06mm, +0.06mm), indicating that the spherical aberration of the lens system at each wavelength is well controlled and can meet the needs of wide spectrum applications.

[0105] Figure 3 This is a schematic diagram of the light fan curve of a lens system provided in the first embodiment of the present invention. The light fan diagram is one of the most commonly used evaluation methods in modern optical design. The horizontal axis is the beam diameter, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays are focused on the same point on the image plane, and the corresponding interval on the vertical axis of the curve is the maximum diffusion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Figure 3 It can be seen that the system's wavelengths in each field of view are all well aligned with the horizontal axis, indicating that the vertical axis aberration of each wavelength of the system is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the system's chromatic aberration is also well corrected, thereby ensuring that the optical system can achieve high-resolution imaging requirements.

[0106] Figure 4 This is a schematic diagram of a field curvature distortion curve of a lens system provided by the first embodiment of the present invention. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, in millimeters (mm); the vertical coordinate represents the normalized image height, without units; Figure 4As can be seen from the left figure, the lens provided by this embodiment has a maximum field of view of 66.2°. Both the meridional and sagittal curvatures of field are effectively controlled at various wavelengths (436nm, 486nm, 546nm, 587nm, 656nm, and 850nm). This means that when imaging, the difference in image quality between the center and the periphery is minimal. The sagittal curvature of field is 0.0494mm, and the meridional curvature of field is 0.0583mm. In the coordinate system on the right, the horizontal coordinate represents the degree of distortion in %, while the vertical coordinate represents the normalized image height, which has no units. Figure 4 As can be seen from the figure on the right, the maximum field of view of the lens system provided by this embodiment is 66.2°, and the maximum distortion is 54.1450%.

[0107] In summary, the lens system provided in Example 1 of the present invention utilizes a hybrid combination of one spherical glass and four aspherical plastic lenses. This system features a reasonable number of lenses, a simple and compact structure, and reasonable focal length and placement of each lens element, enabling daytime and night focus, strong environmental adaptability, and high resolution. This lens system offers a wide monitoring angle and a short overall length. Furthermore, in terms of manufacturability, each lens has low sensitivity, a simple lens surface shape, and ease of manufacture, reducing system processing costs and providing a high cost-effectiveness. This optical lens has an aperture number of 1.55 ≤ FNO ≤ 1.75, a field of view of no less than 130°, an imaging target surface compatible with a 1 / 2.7-inch chip, and an overall optical length of ≤ 18.0 mm.

[0108] Example 2

[0109] Figure 5 This is a schematic structural diagram of a lens system provided in the second embodiment of the present invention. Figure 5 As shown, the lens system provided by Example 2 of the present invention includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, and a fifth lens 105, which are arranged in sequence along the optical axis from the object plane to the image plane. The first lens 101 has a negative optical power, the second lens 102 has a positive optical power, the third lens 103 has a positive optical power, the fourth lens 104 has a negative optical power, and the fifth lens 105 has a positive optical power. The distance on the optical axis from the image side surface of the first lens 101 to the object side surface of the second lens 102 is AT12, the distance on the optical axis from the image side surface of the second lens 102 to the object side surface of the third lens 103 is AT23, and the total optical length of the lens system is TTL. Wherein, 0.085<(AT12+AT23) / TTL<0.185.

[0110] The configuration of the lens is the same as that in the first embodiment, and will not be described again here.

[0111] As another feasible implementation, specific parameters in the lens system are described below.

[0112] Table 4 Optical design values of the lens system in Example 2

[0113] Conditional expression Example 2 Lower limit Upper limit <![CDATA[Φ1 / Φ]]> -0.799 -0.850 -0.650 <![CDATA[Φ2 / Φ]]> 0.225 0.180 0.320 <![CDATA[Φ3 / Φ]]> 0.487 0.380 0.520 ND3 1.457 1.410 1.510 VD3 90.27 85.50 98.50 <![CDATA[Φ4 / Φ]]> -0.598 -0.950 -0.450 <![CDATA[Φ5 / Φ]]> 0.733 0.685 0.985 DL / TTL 0.696 0.645 0.745 (AT12+AT23) / TTL 0.108 0.085 0.185 IC / TTL 0.413 0.355 0.425 IC / EPD 2.214 1.850 2.550 BFL / TTL 0.304 0.265 0.365

[0114] Table 5 Design values of optical physical parameters of a lens system

[0115] Surface number Surface type Curvature radius (mm) Thickness (mm) (nd) / (vd) Semi-diameter (mm) k value 1 even aspherical surface 30.287 0.793 1.535 / 55.71 3.33 10.334 2 even aspherical surface 1.867 1.666 1.81 -0.113 3 even aspherical surface -29.486 3.150 1.640 / 23.50 1.64 40.751 4 even aspherical surface -6.907 -0.017 1.94 -3.107 5 STO INF 0.080 1.96 6 Standard surface 8.619 2.248 1.457 / 90.27 2.60 7 Standard surface -3.822 0.123 2.60 8 even aspherical surface 4.391 0.722 1.661 / 20.38 2.00 -17.748 9 even aspherical surface 1.772 0.275 2.29 -3.872 10 even aspherical surface 3.221 2.101 1.535 / 55.71 2.44 -1.413 11 even aspherical surface -5.278 2.000 2.57 -2.911 12 Standard surface INF 0.210 1.517 / 64.20 2.93 13 Standard surface INF 2.159 2.95 14 Standard surface INF 0.390 1.517 / 64.20 3.26 15 Standard surface INF 0.100 3.30 IMA Standard surface INF 3.32

[0116] The surface numbers in Table 5 are numbered according to the order of the surfaces of each lens. "1" represents the object-side surface of the first lens, "2" represents the image-side surface of the first lens, and so on. "STO" represents the aperture of the lens; the radius of curvature represents the degree of curvature of the lens surface. A positive value represents that the surface is curved toward the image side, and a negative value represents that the surface is curved toward the object side. "INF" represents that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance from the current surface to the next surface. nd represents the refractive index, which represents the light-reflecting ability of the material between the current surface and the next surface. A blank represents that the current position is air, with a refractive index of 1. vd represents the Abbe number, which represents the light-dispersion characteristics of the material between the current surface and the next surface. The semi-aperture represents half the aperture of the current surface. The k value represents the numerical value of the conic coefficient of the aspheric surface.

[0117] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following expression method:

[0118]

[0119] Wherein, z is the axial sagittal height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the radius of curvature; k is the fitting cone coefficient; AG is the coefficient of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspheric polynomial.

[0120] Table 6 Aspheric coefficients of a lens system

[0121]

[0122] Among them, "5.249100E-05" means 5.249100*10 -5 , and the remaining coefficients all use this representation method.

[0123] Based on the above parameter limitations, the optical parameters that can be achieved by the lens system in the second embodiment of the present invention are as follows:

[0124] Focal length f: 2.98mm;

[0125] F#: 1.60;

[0126] Field of view: FOV = 134.3°;

[0127] Total optical length: TTL = 16.00 mm.

[0128] Further, Figure 6 This is a schematic diagram of the spherical aberration curve of a lens system provided by Example 2 of the present invention. The vertical direction represents the normalized aperture, with 0 representing the optical axis and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset from the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of imaging of the system (436nm, 486nm, 546nm, 587nm, 656nm, and 850nm, respectively). Figure 6 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.06mm, +0.06mm), indicating that the spherical aberration of the lens system at each wavelength is well controlled and can meet the needs of wide spectrum applications.

[0129] Figure 7 This is a schematic diagram of the ray fan curve of a lens system provided in Example 2 of the present invention. The ray fan diagram is one of the most commonly used evaluation methods in modern optical design. The horizontal axis is the beam diameter, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays are focused on the same point on the image plane, and the corresponding interval on the vertical axis of the curve is the maximum diffusion range of the light beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Figure 7 It can be seen that the system's wavelengths in each field of view are all well aligned with the horizontal axis, indicating that the vertical axis aberration of each wavelength of the system is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the system's chromatic aberration is also well corrected, thereby ensuring that the optical system can achieve high-resolution imaging requirements.

[0130] Figure 8 This is a schematic diagram of a field curvature distortion curve of a lens system provided by the second embodiment of the present invention. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, and the unit is millimeter (mm); the vertical coordinate represents the normalized image height, and there is no unit; Figure 8 As can be seen from the left figure, the lens provided by this embodiment has a maximum field of view of 67.1°. Both the meridional and sagittal curvatures of field are effectively controlled at various wavelengths (436nm, 486nm, 546nm, 587nm, 656nm, and 850nm). This means that when imaging, the difference in image quality between the center and the periphery is minimal. The sagittal curvature of field is 0.0656mm, and the meridional curvature of field is 0.0842mm. In the coordinate system on the right, the horizontal coordinate represents the degree of distortion in %, while the vertical coordinate represents the normalized image height, which has no units. Figure 8As can be seen from the figure on the right, the maximum field of view of the lens system provided by this embodiment is 67.132°, and the maximum distortion is 53.4091%.

[0131] In summary, the lens system provided in Example 2 of the present invention utilizes a hybrid combination of one spherical glass and four aspherical plastic lenses. This system features a reasonable number of lenses, a simple and compact structure, and reasonable focal length and placement of each lens element, enabling daytime and night focus, strong environmental adaptability, and high resolution. This lens system offers a wide monitoring angle and a short overall length. Furthermore, in terms of manufacturability, each lens has low sensitivity, a simple lens surface shape, and ease of manufacture, reducing system processing costs and providing a high cost-effectiveness. This optical lens has an aperture number of 1.55 ≤ FNO ≤ 1.75, a field of view of no less than 130°, an imaging target surface compatible with a 1 / 2.7-inch chip, and a total optical length of ≤ 18.0 mm.

[0132] Example 3

[0133] Figure 9 This is a schematic structural diagram of a lens system provided by the third embodiment of the present invention. Figure 9 As shown, the lens system provided by Example 3 of the present invention includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, and a fifth lens 105, which are arranged in sequence along the optical axis from the object plane to the image plane; the optical power of the first lens 101 is negative, the optical power of the second lens 102 is positive, the optical power of the third lens 103 is positive, the optical power of the fourth lens 104 is negative, and the optical power of the fifth lens 105 is positive; the distance on the optical axis from the image side surface of the first lens 101 to the object side surface of the second lens 102 is AT12, the distance on the optical axis from the image side surface of the second lens 102 to the object side surface of the third lens 103 is AT23, and the total optical length of the lens system is TTL; wherein 0.085<(AT12+AT23) / TTL<0.185.

[0134] The configuration of the lens is the same as that in the first embodiment, and will not be described again here.

[0135] As another feasible implementation, specific parameters in the lens system are described below.

[0136] Table 7 Optical design values of the lens system in Example 3

[0137] Conditional expression Example 3 Lower limit Upper limit <![CDATA[Φ1 / Φ]]> -0.780 -0.850 -0.650 <![CDATA[Φ2 / Φ]]> 0.271 0.180 0.320 <![CDATA[Φ3 / Φ]]> 0.459 0.380 0.520 ND3 1.459 1.410 1.510 VD3 90.19 85.50 98.50 <![CDATA[Φ4 / Φ]]> -0.801 -0.950 -0.450 <![CDATA[Φ5 / Φ]]> 0.867 0.685 0.985 DL / TTL 0.681 0.645 0.745 (AT12+AT23) / TTL 0.138 0.085 0.185 IC / TTL 0.386 0.355 0.425 IC / EPD 2.099 1.850 2.550 BFL / TTL 0.319 0.265 0.365

[0138] Table 8 Design values of optical physical parameters of a lens system

[0139] Surface number Surface type Curvature radius (mm) Thickness (mm) (nd) / (vd) Semi-diameter (mm) k value 1 even aspherical surface 26.285 0.979 1.535 / 55.71 3.64 -32.364 2 even aspherical surface 1.980 2.134 1.98 -0.282 3 even aspherical surface -18.489 2.780 1.640 / 23.50 1.74 12.728 4 even aspherical surface -5.650 -0.299 1.95 -1.636 5 STO INF 0.530 1.95 6 Standard surface 13.248 2.229 1.457 / 90.27 2.80 7 Standard surface -3.919 0.081 2.80 8 even aspherical surface 6.781 0.812 1.640 / 23.50 2.00 -35.814 9 even aspherical surface 1.761 0.150 2.40 -3.419 10 even aspherical surface 2.857 2.271 1.535 / 55.71 2.50 -1.022 11 even aspherical surface -4.459 2.300 2.58 -0.893 12 Standard surface INF 0.210 1.517 / 64.20 2.96 13 Standard surface INF 2.462 2.97 14 Standard surface INF 0.390 1.517 / 64.20 3.29 15 Standard surface INF 0.100 3.32 IMA Standard surface INF 3.34

[0140] The surface numbers in Table 8 are numbered according to the order of the surfaces of each lens. "1" represents the object-side surface of the first lens, "2" represents the image-side surface of the first lens, and so on. "STO" represents the aperture of the lens; the radius of curvature represents the degree of curvature of the lens surface. A positive value represents that the surface is curved toward the image side, and a negative value represents that the surface is curved toward the object side. "INF" represents that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance from the current surface to the next surface. nd represents the refractive index, which represents the light-reflecting ability of the material between the current surface and the next surface. A blank represents that the current position is air, with a refractive index of 1. vd represents the Abbe number, which represents the dispersion characteristics of the material between the current surface and the next surface. The semi-aperture represents half the aperture size of the current surface. The k value represents the numerical value of the conic coefficient of the aspheric surface.

[0141] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following expression method:

[0142]

[0143] Wherein, z is the axial sagittal height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the radius of curvature; k is the fitting cone coefficient; AG is the coefficient of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspheric polynomial.

[0144] Table 9 Aspheric coefficients of a lens system

[0145]

[0146] Among them, "-1.424670E-03" means -1.424670*10- 3 , and the remaining coefficients all use this representation method.

[0147] Based on the above parameter limitations, the optical parameters that can be achieved by the lens system in the third embodiment of the present invention are as follows:

[0148] Focal length f: 3.15mm;

[0149] F#: 1.69;

[0150] Field of view: FOV = 132.5°;

[0151] Total optical length: TTL = 17.2mm.

[0152] Further, Figure 10This is a schematic diagram of the spherical aberration curve of a lens system provided by Example 3 of the present invention. The vertical direction represents the normalized aperture, with 0 representing the optical axis and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset from the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of imaging of the system (436nm, 486nm, 546nm, 587nm, 656nm, and 850nm, respectively). Figure 10 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of the lens system at each wavelength is well controlled and can meet the needs of wide spectrum applications.

[0153] Figure 11 This is a schematic diagram of the ray fan curve of a lens system provided in the third embodiment of the present invention. The ray fan diagram is one of the most commonly used evaluation methods in modern optical design. The horizontal axis is the beam diameter, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays are focused on the same point on the image plane, and the corresponding interval on the vertical axis of the curve is the maximum diffusion range of the light beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Figure 11 It can be seen that the system's wavelengths in each field of view are all well aligned with the horizontal axis, indicating that the vertical axis aberration of each wavelength of the system is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the system's chromatic aberration is also well corrected, thereby ensuring that the optical system can achieve high-resolution imaging requirements.

[0154] Figure 12 This is a schematic diagram of a field curvature distortion curve of a lens system provided by the third embodiment of the present invention. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, in millimeters (mm); the vertical coordinate represents the normalized image height, without units; Figure 12 As can be seen from the left figure, the lens provided by this embodiment has a maximum field of view of 66°. Both the meridional and sagittal curvatures of field are effectively controlled at various wavelengths (436nm, 486nm, 546nm, 587nm, 656nm, and 850nm). This means that when imaging, the difference in image quality between the center and the periphery is minimal. The sagittal curvature of field is 0.0887mm, and the meridional curvature of field is 0.0846mm. In the coordinate system on the right, the horizontal coordinate represents the degree of distortion in %, while the vertical coordinate represents the normalized image height, which has no units. Figure 12 As can be seen from the figure on the right, the maximum field of view of the lens system provided by this embodiment is 66°, and the maximum distortion is 53.3317%.

[0155] In summary, the lens system provided in Example 3 of the present invention utilizes eight glass-plastic hybrid lenses. This optimal number of lenses results in a simple and compact structure. The focal length and placement of each lens are optimized, enabling daytime and night focus, strong environmental adaptability, and high resolution. Furthermore, the large aperture, wide angle, and large image surface design make this lens system highly competitive in the market. The optical lens has an F-number (FNO) of 1.60, a field of view of no less than 160°, an imaging target surface compatible with 1 / 1.6-inch chips, and a total optical length of no more than 35mm, meeting the requirements for ultra-high-definition imaging.

[0156] Example 4

[0157] Figure 13 This is a structural diagram of a lens system provided by the fourth embodiment of the present invention. Figure 13 As shown, the lens system provided by Example 4 of the present invention includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, and a fifth lens 105, which are arranged in sequence along the optical axis from the object plane to the image plane; the optical power of the first lens 101 is negative, the optical power of the second lens 102 is positive, the optical power of the third lens 103 is positive, the optical power of the fourth lens 104 is negative, and the optical power of the fifth lens 105 is positive; the distance on the optical axis from the image side surface of the first lens 101 to the object side surface of the second lens 102 is AT12, the distance on the optical axis from the image side surface of the second lens 102 to the object side surface of the third lens 103 is AT23, and the total optical length of the lens system is TTL; wherein 0.085<(AT12+AT23) / TTL<0.185.

[0158] The configuration of the lens is the same as that in the first embodiment, and will not be described again here.

[0159] As another feasible implementation, specific parameters in the lens system are described below.

[0160] Table 10: Optical design values of the lens system in Example 4

[0161] Conditional expression Example 4 Lower limit Upper limit <![CDATA[Φ1 / Φ]]> -0.804 -0.850 -0.650 <![CDATA[Φ2 / Φ]]> 0.267 0.180 0.320 <![CDATA[Φ3 / Φ]]> 0.461 0.380 0.520 ND3 1.437 1.410 1.510 VD3 95.10 85.50 98.50 <![CDATA[Φ4 / Φ]]> -0.765 -0.950 -0.450 <![CDATA[Φ5 / Φ]]> 0.845 0.685 0.985 DL / TTL 0.670 0.645 0.745 (AT12+AT23) / TTL 0.146 0.085 0.185 IC / TTL 0.393 0.355 0.425 IC / EPD 2.121 1.850 2.550 BFL / TTL 0.330 0.265 0.365

[0162] Table 11 Design values of optical physical parameters of a lens system

[0163] Surface number Surface type Curvature radius (mm) Thickness (mm) (nd) / (vd) Semi-diameter (mm) k value 1 even aspherical surface 14.301 0.998 1.535 / 55.71 3.76 -75.624 2 even aspherical surface 1.776 2.073 1.95 -0.296 3 even aspherical surface -18.350 2.726 1.640 / 23.50 1.77 35.178 4 even aspherical surface -5.662 0.387 2.02 -1.549 5 Standard surface 11.307 2.147 1.437 / 95.10 2.80 6 Standard surface -3.778 -0.089 2.80 7 STO INF 0.176 1.98 8 even aspherical surface 6.011 0.621 1.640 / 23.50 2.00 -42.582 9 even aspherical surface 1.757 0.147 2.37 -3.855 10 even aspherical surface 2.854 2.097 1.535 / 55.71 2.48 -1.153 11 even aspherical surface -4.828 2.500 2.57 -0.562 12 Standard surface INF 0.210 1.517 / 64.20 2.96 13 Standard surface INF 2.347 2.98 14 Standard surface INF 0.390 1.517 / 64.20 3.27 15 Standard surface INF 0.100 3.31 IMA Standard surface INF 3.32

[0164] The surface numbers in Table 11 are numbered according to the order of the surfaces of each lens. "1" represents the object-side surface of the first lens, "2" represents the image-side surface of the first lens, and so on. "STO" represents the aperture of the lens; the radius of curvature represents the degree of curvature of the lens surface. A positive value represents that the surface is curved toward the image side, and a negative value represents that the surface is curved toward the object side. "INF" represents that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance from the current surface to the next surface. nd represents the refractive index, which represents the light-reflecting ability of the material between the current surface and the next surface. A blank represents that the current position is air, with a refractive index of 1. vd represents the Abbe number, which represents the light-dispersion characteristics of the material between the current surface and the next surface. The semi-aperture represents half the aperture of the current surface. The k value represents the numerical value of the conic coefficient of the aspheric surface.

[0165] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following expression method:

[0166]

[0167] Wherein, z is the axial sagittal height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the radius of curvature; k is the fitting cone coefficient; AG is the coefficient of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspheric polynomial.

[0168] Table 12 Aspheric coefficients of a lens system

[0169]

[0170] Among them, "-1.316530E-03" means -1.316530*10- 3 , and the remaining coefficients all use this representation method.

[0171] Based on the above parameter limitations, the optical parameters that can be achieved by the lens system in the fourth embodiment of the present invention are as follows:

[0172] Focal length f: 3.12mm;

[0173] F#: 1.63;

[0174] Field of view: FOV = 136.8°;

[0175] Total optical length: TTL = 16.83mm.

[0176] Further, Figure 14This is a schematic diagram of the spherical aberration curve of a lens system provided by Example 4 of the present invention. The vertical direction represents the normalized aperture, with 0 representing the optical axis and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset from the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of imaging of the system (436nm, 486nm, 546nm, 587nm, 656nm, and 850nm, respectively). Figure 14 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.08mm, +0.08mm), indicating that the spherical aberration of the lens system at each wavelength is well controlled and can meet the needs of wide spectrum applications.

[0177] Figure 15 This is a schematic diagram of the ray fan curve of a lens system provided by the fourth embodiment of the present invention. The ray fan diagram is one of the most commonly used evaluation methods in modern optical design. The horizontal axis is the beam diameter, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays are focused on the same point on the image plane, and the corresponding interval on the vertical axis of the curve is the maximum diffusion range of the light beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Figure 15 It can be seen that the system's wavelengths in each field of view are all well aligned with the horizontal axis, indicating that the vertical axis aberration of each wavelength of the system is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the system's chromatic aberration is also well corrected, thereby ensuring that the optical system can achieve high-resolution imaging requirements.

[0178] Figure 16 This is a schematic diagram of a field curvature distortion curve of a lens system provided by the fourth embodiment of the present invention. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, in millimeters (mm); the vertical coordinate represents the normalized image height, without units; Figure 16 As can be seen from the left figure, the lens provided by this embodiment has a maximum field of view of 68.4°. Both the meridional and sagittal curvatures of field are effectively controlled at various wavelengths (436nm, 486nm, 546nm, 587nm, 656nm, and 850nm). This means that when imaging, the difference in image quality between the center and the periphery is minimal. The sagittal curvature of field is 0.0417mm, and the meridional curvature of field is 0.0750mm. In the coordinate system on the right, the horizontal axis represents the degree of distortion in %, while the vertical axis represents the normalized image height, which has no units. Figure 16 As can be seen from the figure on the right, the maximum field of view of the lens system provided by this embodiment is 68.4°, and the maximum distortion is 57.8480%.

[0179] In summary, the lens system provided in Example 4 of the present invention utilizes eight glass-plastic hybrid lenses. This optimal number of lenses results in a simple and compact structure. The focal length and placement of each lens are optimized, enabling daytime and night focus, strong environmental adaptability, and high resolution. Furthermore, the large aperture, wide angle, and large image surface design make this lens system highly competitive in the market. The optical lens has an F-number (FNO) of 1.60, a field of view of no less than 160°, an imaging target surface compatible with 1 / 1.6-inch chips, and a total optical length of no more than 35mm, meeting the requirements for ultra-high-definition imaging.

[0180] Example 5

[0181] Figure 17 This is a structural diagram of a lens system provided by the fifth embodiment of the present invention. Figure 17 As shown, the lens system provided by Example 5 of the present invention includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, and a fifth lens 105, which are arranged in sequence along the optical axis from the object plane to the image plane; the optical power of the first lens 101 is negative, the optical power of the second lens 102 is positive, the optical power of the third lens 103 is positive, the optical power of the fourth lens 104 is negative, and the optical power of the fifth lens 105 is positive; the distance on the optical axis from the image side surface of the first lens 101 to the object side surface of the second lens 102 is AT12, the distance on the optical axis from the image side surface of the second lens 102 to the object side surface of the third lens 103 is AT23, and the total optical length of the lens system is TTL; wherein 0.085<(AT12+AT23) / TTL<0.185.

[0182] The configuration of the lens is the same as that in the first embodiment, and will not be described again here.

[0183] As another feasible implementation, specific parameters in the lens system are described below.

[0184] Table 13 Optical design values of the lens system in Example 5

[0185] Conditional expression Example 5 Lower limit Upper limit <![CDATA[Φ1 / Φ]]> -0.789 -0.850 -0.650 <![CDATA[Φ2 / Φ]]> 0.277 0.180 0.320 <![CDATA[Φ3 / Φ]]> 0.452 0.380 0.520 ND3 1.437 1.410 1.510 VD3 95.10 85.50 98.50 <![CDATA[Φ4 / Φ]]> -0.774 -0.950 -0.450 <![CDATA[Φ5 / Φ]]> 0.846 0.685 0.985 DL / TTL 0.678 0.645 0.745 (AT12+AT23) / TTL 0.134 0.085 0.185 IC / TTL 0.393 0.355 0.425 IC / EPD 2.141 1.850 2.550 BFL / TTL 0.322 0.265 0.365

[0186] Table 14 Design values of optical physical parameters of a lens system

[0187] Surface number Surface type Curvature radius (mm) Thickness (mm) (nd) / (vd) Semi-diameter (mm) k value 1 even aspherical surface 29.616 1.000 1.535 / 55.71 3.73 -69.603 2 even aspherical surface 1.940 2.028 1.96 -0.206 3 even aspherical surface -19.639 2.874 1.640 / 23.50 1.72 35.920 4 even aspherical surface -5.571 -0.306 1.96 -1.010 5 STO INF 0.530 1.96 6 Standard surface 12.203 2.184 1.437 / 95.10 2.80 7 Standard surface -3.748 0.062 2.80 8 even aspherical surface 6.263 0.696 1.640 / 23.50 1.95 -37.763 9 even aspherical surface 1.746 0.149 2.34 -3.694 10 even aspherical surface 2.880 2.198 1.545 / 55.99 2.45 -0.959 11 even aspherical surface -4.743 2.500 2.56 -0.610 12 Standard surface INF 0.210 1.517 / 64.20 2.96 13 Standard surface INF 2.210 2.98 14 Standard surface INF 0.390 1.517 / 64.20 3.27 15 Standard surface INF 0.100 3.30 IMA Standard surface INF 3.31

[0188] The surface numbers in Table 14 are numbered according to the order of the surfaces of each lens. "1" represents the object-side surface of the first lens, "2" represents the image-side surface of the first lens, and so on. "STO" represents the aperture of the lens; the radius of curvature represents the degree of curvature of the lens surface. A positive value represents that the surface is curved toward the image side, and a negative value represents that the surface is curved toward the object side. "INF" represents that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance from the current surface to the next surface. nd represents the refractive index, which represents the light-reflecting ability of the material between the current surface and the next surface. A blank represents that the current position is air, with a refractive index of 1. vd represents the Abbe number, which represents the dispersion characteristics of the material between the current surface and the next surface. The semi-aperture represents half the aperture size of the current surface. The k value represents the numerical value of the conic coefficient of the aspheric surface.

[0189] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following expression method:

[0190]

[0191] Wherein, z is the axial sagittal height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the radius of curvature; k is the fitting cone coefficient; AG is the coefficient of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspheric polynomial.

[0192] Table 15 Aspheric coefficients of a lens system

[0193]

[0194] Among them, "-1.022411E-03" means -1.022411*10- 3 , and the remaining coefficients all use this representation method.

[0195] Based on the above parameter limitations, the optical parameters that can be achieved by the lens system in the fifth embodiment of the present invention are as follows:

[0196] Focal length f: 3.09mm;

[0197] F#: 1.68;

[0198] Field of view: FOV = 140.2°;

[0199] Total optical length: TTL = 16.83mm.

[0200] Further, Figure 18This is a schematic diagram of the spherical aberration curve of a lens system provided by Example 5 of the present invention. The vertical direction represents the normalized aperture, with 0 representing the optical axis and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of imaging of the system (436nm, 486nm, 546nm, 587nm, 656nm, and 850nm, respectively). Figure 18 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.06mm, +0.06mm), indicating that the spherical aberration of the lens system at each wavelength is well controlled and can meet the needs of wide spectrum applications.

[0201] Figure 19 This is a schematic diagram of the ray fan curve of a lens system provided by the fifth embodiment of the present invention. The ray fan diagram is one of the most commonly used evaluation methods in modern optical design. The horizontal axis is the beam diameter, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays are focused on the same point on the image plane, and the corresponding interval on the vertical axis of the curve is the maximum diffusion range of the light beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Figure 19 It can be seen that the system's wavelengths in each field of view are all well aligned with the horizontal axis, indicating that the vertical axis aberration of each wavelength of the system is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the system's chromatic aberration is also well corrected, thereby ensuring that the optical system can achieve high-resolution imaging requirements.

[0202] Figure 20 This is a schematic diagram of a field curvature distortion curve of a lens system provided by Example 5 of the present invention. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, in millimeters (mm); the vertical coordinate represents the normalized image height, without units; Figure 20 As can be seen in the left figure, the lens provided by this embodiment has a maximum field of view of 68.0°. Both the meridional and sagittal curvatures of field are effectively controlled at various wavelengths (436nm, 486nm, 546nm, 587nm, 656nm, and 850nm). This means that when imaging, the difference in image quality between the center and the periphery is minimal. The sagittal curvature of field is 0.0590mm, and the meridional curvature of field is 0.1192mm. In the coordinate system on the right, the horizontal coordinate represents the degree of distortion in %, while the vertical coordinate represents the normalized image height, which has no units. Figure 20 As can be seen from the figure on the right, the maximum field of view of the lens system provided by this embodiment is 68.0°, and the maximum distortion is 56.8002%.

[0203] In summary, the lens system provided in Example 5 of the present invention utilizes eight glass-plastic hybrid lenses. This optimal number of lenses results in a simple and compact structure. The focal length and placement of each lens are optimized, enabling daytime and night focus, strong environmental adaptability, and high resolution. Furthermore, the large aperture, wide angle, and large image surface design make this lens system highly competitive in the market. The optical lens has an F-number (FNO) of 1.60, a field of view of no less than 160°, an imaging target surface compatible with 1 / 1.6-inch chips, and a total optical length of no more than 35mm, meeting the requirements for ultra-high-definition imaging.

[0204] The above specific embodiments do not limit the scope of protection of this utility model. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model shall be included within the scope of protection of this utility model.

Claims

1. A lens system, characterized in that: comprising a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence along the optical axis from the object plane to the image plane; The optical power of the first lens is negative, the optical power of the second lens is positive, the optical power of the third lens is positive, the optical power of the fourth lens is negative, and the optical power of the fifth lens is positive; The distance on the optical axis from the image side of the first lens to the object side of the second lens is AT12, the distance on the optical axis from the image side of the second lens to the object side of the third lens is AT23, and the total optical length of the lens system is TTL; Among them, 0.085<(AT12+AT23) / TTL<0.

185.

2. The lens system according to claim 1, wherein: The focal power of the first lens is Φ1, the focal power of the second lens is Φ2, the focal power of the third lens is Φ3, the focal power of the fourth lens is Φ4, the focal power of the fifth lens is Φ5, and the focal power of the lens system is Φ; Among them, -0.85≤Φ1 / Φ≤-0.65, 0.18≤Φ2 / Φ≤0.32, 0.38≤Φ3 / Φ≤0.52, -0.95≤Φ4 / Φ≤-0.45, 0.685≤Φ5 / Φ≤0.

985.

3. The lens system according to claim 1, wherein: The refractive index of the third lens is ND3 and the Abbe number is VD3; Among them, 1.41≤ND3≤1.51, 85.50≤VD3≤98.

50.

4. The lens system according to claim 1, wherein: The distance on the optical axis from the object side of the first lens to the image side of the fifth lens is DL, and the total optical length of the lens system is TTL; Among them, 0.645 <DL / TTL<0.745。 5. The lens system according to claim 1, wherein: The image height of the lens system is IC, the total optical length of the lens system is TTL, and the entrance pupil diameter of the lens system is EPD; Among them, 0.355≤IC / TTL≤0.425, 1.85≤IC / EPD≤2.

55.

6. The lens system according to claim 1, wherein: The optical back focus of the lens system is BFL, and the total optical length of the lens system is TTL; Among them, 0.265≤BFL / TTL≤0.

365.

7. The lens system according to claim 1, wherein: The first lens is a plastic aspheric lens, the second lens is a plastic aspheric lens, the third lens is a glass spherical lens, the fourth lens is a plastic aspheric lens, and the fifth lens is a plastic aspheric lens.

8. The lens system according to claim 1, wherein: The first lens includes a first object-side surface close to the object plane and a first image-side surface close to the image plane, the first object-side surface is convex, the first image-side surface is concave, and the first lens is a meniscus lens; The second lens includes a second object-side surface close to the object plane and a second image-side surface close to the image plane, the second object-side surface is concave, the first image-side surface is convex, and the second lens is a meniscus lens; The third lens comprises a third object-side surface close to the object plane and a third image-side surface close to the image plane, the third object-side surface is a convex surface, and the first image-side surface is a convex surface; The fourth lens comprises a fourth object-side surface close to the object plane and a fourth image-side surface close to the image plane, the fourth object-side surface is convex, and the fourth image-side surface is concave; The fifth lens includes a fifth object-side surface close to the object plane and a fifth image-side surface close to the image plane. The fifth object-side surface is a convex surface, and the fifth image-side surface is a convex surface.

9. The lens system according to claim 1, wherein: The lens system also includes an aperture stop and a filter; The aperture stop is arranged in the optical path between the second lens and the third lens, or the aperture stop is arranged in the optical path between the third lens and the fourth lens; The filter is arranged in the optical path between the fifth lens and the image plane.

10. The lens system according to claim 1, wherein: The aperture of the lens system is FNO, the total focal length is f, the field of view angle is FOV, and the total optical length is TTL; Among them, 1.55≤FNO≤1.75; 2.90≤f≤3.45; FOV≥130°; TTL≤18.0mm.

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