Imaging system

Abstract

The invention discloses an imaging system. The invention relates to a zoom lens which sequentially comprises a first lens, a second lens with positive focal power, a third lens, a fourth lens, a fifth lens with positive focal power, a sixth lens, a seventh lens with positive focal power, an eighth lens with positive focal power, a ninth lens with negative focal power and a tenth lens with negative focal power from an object side to an image side along an optical axis, the eleventh lens has positive focal power, the twelfth lens has positive focal power, and the thirteenth lens has positive focal power. The number of lenses with focal power in the imaging system is thirteen.

Description

Technical Field

[0001] The present application relates to the field of optical elements, and more specifically, to an imaging system. Background Art

[0002] With the development of society, smartphones are portable and have increasingly powerful camera functions, so taking photos with mobile phones is very popular among the public. However, due to the size of mobile phones, the application of mobile phone lenses in taking photos is limited to a certain extent. In response to the problem of mobile phone lenses, more and more external lenses that are compatible with mobile phones have appeared on the market as auxiliary lenses to meet the needs of diverse functions and application occasions of taking photos.

[0003] At present, the external detachable lenses on the market that are installed on the built-in lens of the mobile phone to improve the imaging quality of the mobile phone still cannot meet the usage needs of users; especially for the external detachable telephoto lens of the mobile phone, while ensuring that the mobile phone can achieve telephoto shooting after the external lens is installed, it is impossible to obtain smaller distortion, higher illumination and higher imaging quality, which leads to problems such as large degree of deformation of the imaging picture, dark brightness of the imaging picture and poor imaging quality.

[0004] Therefore, there is an urgent need for an external telephoto lens that can be used in combination with a conventional mobile phone lens, so that the camera lens as a whole has low distortion, high illumination and high imaging quality while meeting the telephoto characteristics, thereby realizing the telephoto shooting function. Summary of the invention

[0005] On one hand, the present application provides an imaging system, which includes, in order from the object side to the image side along the optical axis: a first lens with positive or negative optical power, a second lens with positive optical power, a third lens with positive or negative optical power, a fourth lens with positive or negative optical power, a fifth lens with positive optical power, a sixth lens with positive or negative optical power, a seventh lens with positive optical power, an eighth lens with positive optical power, a ninth lens with negative optical power, a tenth lens with negative optical power, an eleventh lens with positive optical power, a twelfth lens with positive optical power; and a thirteenth lens with positive optical power. The number of lenses with optical power in the imaging system is thirteen.

[0006] In one embodiment, the positive and negative properties of the optical powers of the first lens and the third lens are opposite, and the positive and negative properties of the optical powers of the third lens and the fourth lens are opposite.

[0007] In one embodiment, the object side surface of the first lens is convex; the object side surface of the second lens is convex; the object side surface of the third lens is concave, and the image side surface is concave; or, the object side surface of the third lens is convex, and the image side surface is convex; the object side surface of the fourth lens is convex or concave; the object side surface of the fifth lens is convex or concave, and the image side surface is convex; the object side surface of the sixth lens is convex, and the image side surface is concave; or, the object side surface of the sixth lens is concave, and the image side surface is convex; the object side surface of the seventh lens is convex; the object side surface of the eighth lens is convex, and the image side surface is concave; the object side surface of the ninth lens is convex, and the image side surface is concave; the object side surface and the image side surface of the tenth lens are both concave; the object side surface and the image side surface of the eleventh lens are both convex; the image side surface of the twelfth lens is convex; and the object side surface and the image side surface of the thirteenth lens are both convex.

[0008] In one embodiment, the imaging system further includes an imaging lens located on the image side of the thirteenth lens, wherein the imaging lens includes a plurality of lenses.

[0009] In one embodiment, the second lens, the third lens and the fourth lens form a triplet lens group, the sixth lens and the seventh lens form a doublet lens group, the eighth lens and the ninth lens form a doublet lens group, and the tenth lens and the eleventh lens form a doublet lens group.

[0010] In one embodiment, the first lens and the second lens form a doublet lens group, the third lens and the fourth lens form a doublet lens group, the eighth lens and the ninth lens form a doublet lens group, and the tenth lens and the eleventh lens form a doublet lens group.

[0011] In one embodiment, the imaging system satisfies: 0.08≤f9 / f≤0.24, wherein f9 is the effective focal length of the ninth lens, and f is the effective focal length of the imaging system.

[0012] In one embodiment, the imaging system satisfies at least one of the following conditional expressions: 0.14≤f10 / f≤0.32, -0.45≤f11 / f≤-0.32, wherein f10 is the effective focal length of the tenth lens, f11 is the effective focal length of the eleventh lens, and f is the effective focal length of the imaging system.

[0013] In one embodiment, the imaging system satisfies: -1.35≤f13 / f≤-0.7, wherein f13 is the effective focal length of the thirteenth lens, and f is the effective focal length of the imaging system.

[0014] In one embodiment, the imaging system satisfies: 1.1≤fd1 / f≤1.8, wherein fd1 is the combined effective focal length of the eighth lens and the ninth lens, and f is the effective focal length of the imaging system.

[0015] In one embodiment, the imaging system satisfies: 2.15≤fa / fb≤2.5, wherein fa is the combined effective focal length of the first lens to the ninth lens, and fb is the combined effective focal length of the tenth lens to the thirteenth lens.

[0016] In one embodiment, the imaging system includes an aperture stop, which is arranged between the image side surface of the thirteenth lens and the imaging lens.

[0017] In one embodiment, the imaging system satisfies at least one of the following conditional formulas: 0.15≤Thb / TTa≤0.4, 0.15≤Et / TTa≤0.25, 1.9≤D1 / Ed≤2.5, wherein Thb is the axial distance from the object side of the tenth lens to the image side of the thirteenth lens, TTa is the axial distance from the object side of the first lens to the image side of the thirteenth lens, Et is the axial distance from the image side of the thirteenth lens to the aperture, D1 is the optical full aperture of the object side of the first lens, and Ed is the full aperture of the aperture.

[0018] In one embodiment, the imaging system satisfies at least one of the following conditional equations: -1.80≤f1 / f≤1.42, -1.40≤f2 / f≤-0.7, -1.1≤f3 / f≤0.42, -1≤f4 / f≤0.89, -3.8≤f5 / f≤-1.15, 0.4≤|f6 / f|≤9, -1.7≤f7 / f≤-0.25, -0.76≤f12 / f≤-0.38, wherein f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, f6 is the effective focal length of the sixth lens, f7 is the effective focal length of the seventh lens, f12 is the effective focal length of the twelfth lens, and f is the effective focal length of the imaging system.

[0019] In one embodiment, the imaging system satisfies at least one of the following conditional expressions: 25≤vd3≤95.2, 18≤vd5≤95.2, 18≤vd7≤35, 55≤vd13≤95.2, wherein vd3 is the Abbe number of the third lens, vd5 is the Abbe number of the fifth lens, vd7 is the Abbe number of the seventh lens, and vd13 is the Abbe number of the thirteenth lens.

[0020] In one embodiment, the imaging system satisfies at least one of the following conditions: -1.68≤f1 / f≤1.34, -1.32≤f2 / f≤-0.73, -1.05≤f3 / f≤0.4, -0.95≤f4 / f≤0.85, -3.57≤f5 / f≤-1.22, 0.45≤|f6 / f|≤8.75, -1.63≤f7 / f≤-0.3, 0.12≤f9 / f≤0.21, 0.17≤f10 / f≤0.3, -0.44≤f11 / f≤-0.34, -0.7≤f12 / f≤-0.4, -1.3≤f13 / f≤-0.72, 1.13≤fd1 / f≤1.75, 2.18≤fa / fb≤2.4, 0.19≤Thb / TTa≤0.35, 29≤vd3≤82, 22≤vd5≤82, 20≤vd7≤30, 63≤vd13≤95.2, where f1 is the effective focal length of the first lens. The effective focal length of the imaging system is shown in FIG1 , f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, f6 is the effective focal length of the sixth lens, f7 is the effective focal length of the seventh lens, f9 is the effective focal length of the ninth lens, f10 is the effective focal length of the tenth lens, f11 is the effective focal length of the eleventh lens, f12 is the effective focal length of the twelfth lens, f13 is the effective focal length of the thirteenth lens, f is the effective focal length of the imaging system, fd1 is the combined effective focal length of the eighth lens and the ninth lens, fa is the combined effective focal length of the first lens to the ninth lens, fb is the combined effective focal length of the tenth lens to the thirteenth lens, Thb is the axial distance from the object side surface of the tenth lens to the image side surface of the thirteenth lens, TTa is the axial distance from the object side surface of the first lens to the image side surface of the thirteenth lens, vd3 is the Abbe number of the third lens, vd5 is the Abbe number of the fifth lens, vd7 is the Abbe number of the seventh lens, and vd13 is the Abbe number of the thirteenth lens.

[0021] The present application provides an imaging system using multiple lenses (for example, thirteen lenses). By reasonably setting the optical focal length of each lens, the imaging system can have a telephoto characteristic, reduce the optical distortion of the imaging system, improve the relative illumination of the imaging system, and improve aberration problems such as chromatic aberration and astigmatism, thereby improving the imaging quality of the imaging system, making the absolute value of optical distortion |DIS|≤2%, the vertical axis chromatic aberration less than 3.5μm, and the MTF curve of the central field of view at a frequency of 230lp / mm. The MTF curve is above 0.6 and the MTF curve in the entire field of view is above 0.2, and the relative illumination is ≥55%. At the same time, when it is adapted to an imaging lens with a focal length of 22.48mm, an angular magnification of 2.35X can be achieved, so that the imaging system has a better telescopic function. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0023] Figure 1 is a schematic structural diagram of an imaging system according to Embodiment 1 of the present application;

[0024] Figure 2 is a schematic structural diagram of a lens group included in an imaging system according to Embodiment 1 of the present application;

[0025] Figure 3 is a distortion curve diagram of the imaging system according to Embodiment 1 of the present application;

[0026] Figure 4 is a schematic structural diagram of a lens group included in an imaging system according to Embodiment 2 of the present application;

[0027] Figure 5 is a distortion curve diagram of an imaging system according to Embodiment 2 of the present application;

[0028] Figure 6 is a schematic structural diagram of a lens group included in an imaging system according to Embodiment 3 of the present application;

[0029] Figure 7 is a distortion curve diagram of an imaging system according to Embodiment 3 of the present application;

[0030] Figure 8 is a schematic structural diagram of a lens group included in an imaging system according to Embodiment 4 of the present application;

[0031] Fig. 9 is a distortion curve diagram of an imaging system according to Embodiment 4 of the present application;

[0032] Fig.10 is a schematic structural diagram of a lens group included in an imaging system according to Embodiment 5 of the present application;

[0033] Fig.11 It is a distortion curve diagram of the imaging system according to Example 5 of the present application. DETAILED DESCRIPTION

[0034] In order to facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application, and do not limit the scope of the present application in any way. Throughout the specification, the same figure numbers refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0035] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0036] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0037] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object side of the lens, and the surface of each lens closest to the imaging side is called the image side of the lens.

[0038] It should also be understood that the terms "comprises", "including", "having", "includes" and / or "comprising", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0039] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0040] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The features, principles and other aspects of the present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0041] In an exemplary embodiment, the imaging system provided by the present application may include a lens group and an imaging lens arranged in sequence from the object side to the image side along the optical axis, wherein the lens group and the imaging lens each include a plurality of lenses. As an example, the lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens and a thirteenth lens having optical power in sequence from the object side to the image side along the optical axis, and the imaging lens is located on the image side of the thirteenth lens. As an example, the lens group of the imaging system can be adapted to an imaging lens with a focal length of 22.48 mm.

[0042] In an exemplary embodiment, the imaging lens may be, for example, a mobile phone lens, and the lens group in the adapted imaging system may enable the imaging system to have the characteristics of telephoto, high illumination, high image quality, and low distortion, and may achieve a better telescopic function. In some cases, the number of lenses included in the imaging lens may be arbitrarily set according to actual needs.

[0043] In an exemplary embodiment, the imaging system may further include an aperture for limiting the light beam to ensure that the light emitted from the lens group of the imaging system enters the imaging lens behind the aperture in parallel, and ensure that when the lens group of the imaging system is used as an auxiliary lens, it does not affect the use of the imaging lens as a main camera lens, thereby improving the imaging quality of the imaging system. Exemplarily, the aperture is arranged between the image side surface of the thirteenth lens and the imaging lens.

[0044] In an exemplary embodiment, the first lens may have positive or negative optical power. When the optical power of the first lens is positive, both the object side and the image side may be convex; when the optical power of the first lens is negative, the object side may be convex and the image side may be concave. By setting the object side of the first lens to be convex, it is helpful to reduce the incident angle of the field light on the object side, so that the light can enter the imaging system better, reduce the generation of aberrations and distortion, and help achieve high image quality of the lens and reduce distortion.

[0045] In an exemplary embodiment, the second lens may have positive focal power, and its object side surface may be convex. By setting the second lens as a positive lens and setting the object side surface of the second lens as a convex surface, it is helpful to control the trend of the light incident on the second lens, and further collect the light, which is helpful to make the light enter the imaging system better, reduce the generation of spherical aberration and distortion, and help to achieve high image quality of the lens and reduce distortion. As an example, the image side surface of the second lens may be convex, concave or flat.

[0046] In an exemplary embodiment, the third lens may have positive or negative optical power. When the optical power of the third lens is positive, both the object side and the image side thereof may be convex; when the optical power of the third lens is negative, both the object side and the image side thereof may be concave. By setting the third lens as a positive lens, both the object side and the image side thereof are convex, so that it can be better matched with the first lens and the fourth lens with negative optical power, effectively control the trend of light, reduce the divergence of light, make the trend of the outgoing light tend to be gentle, help reduce the generation of spherical aberration, and effectively correct chromatic aberration, which is conducive to achieving high image quality of the lens. By setting the third lens as a negative lens, both the object side and the image side thereof are concave, so that it can be better matched with the first lens and the fourth lens with positive optical power, effectively control the trend of light, help diverge the light converged by the first lens and the second lens, reduce the generation of spherical aberration, and help achieve high image quality of the lens and ensure tolerance performance.

[0047] In an exemplary embodiment, the fourth lens may have positive or negative optical power. When the optical power of the fourth lens is positive, its object side surface may be convex; when the optical power of the fourth lens is negative, its object side surface may be concave. By setting the fourth lens as a positive lens and its object side surface as a convex surface, it can be better matched with the third lens with a negative optical power, further focusing the light, reducing the divergence of the light, and making the trend of the outgoing light tend to be gentle. At the same time, negative spherical aberration is introduced, which is beneficial to balancing the spherical aberration of the optical system and improving the resolution quality. By setting the fourth lens as a negative lens and its object side surface as a concave surface, it can be better matched with the third lens with a positive optical power, so that the light beam changes from a focusing trend to a parallel light trend, better realizes the light transition, reduces the generation of spherical aberration, and is beneficial to achieve high image quality and ensure tolerance performance. As an example, the image side surface of the fourth lens may be a plane, a concave surface, or a convex surface.

[0048] In an exemplary embodiment, the second lens may have positive power, the third lens may have negative power, the fourth lens may have positive power, and the second lens, the third lens, and the fourth lens may constitute a triplet lens group.

[0049] In an exemplary embodiment, the first lens may have negative power, the second lens may have positive power, the third lens may have positive power, and the fourth lens may have negative power. The first lens and the second lens may form a doublet lens group, and the third lens and the fourth lens may form a doublet lens group.

[0050] In an exemplary embodiment, the fifth lens may have positive power, and its image side surface may be convex. By setting the fifth lens as a positive lens and its image side surface as a convex surface, it is helpful to control the trend of light, converge light, effectively limit the incident height of light on the rear optical lens, effectively reduce the aperture size of the rear lens, and help achieve miniaturization of the lens volume, and effectively reduce the tolerance sensitivity of the lens. As an example, the object side surface of the fifth lens may be a concave surface or a convex surface.

[0051] In an exemplary embodiment, the sixth lens may have positive or negative power. When the power of the sixth lens is positive, its object side surface may be concave and its image side surface may be convex; when the power of the sixth lens is negative, its object side surface may be convex and its image side surface may be concave.

[0052] In an exemplary embodiment, the seventh lens may have positive power, and its object side surface may be convex. By reasonably matching the power and lens shape of the sixth lens and the seventh lens, the trend of light can be effectively controlled, and the light can be further gathered, so that the light can be converged to reduce the optical path, which is conducive to reducing the generation of spherical aberration and improving the image quality of the lens. As an example, the image side surface of the seventh lens can be convex, concave or flat.

[0053] In an exemplary embodiment, the sixth lens may have negative optical power, the seventh lens may have positive optical power, and the sixth lens and the seventh lens may form a doublet lens group, which effectively corrects the chromatic aberration generated by the first lens to the fifth lens, thereby facilitating the realization of high image quality.

[0054] In example embodiments, the eighth lens may have positive refractive power, an object-side surface thereof may be convex, and an image-side surface thereof may be concave.

[0055] In an exemplary embodiment, the ninth lens may have negative power, its object side surface may be convex, and its image side surface may be concave. By matching the positive and negative power of the eighth lens and the ninth lens and matching the lens shapes, the trend of light can be effectively controlled, the light can be converged, and spherical aberration, astigmatism and field curvature can be effectively corrected, which is conducive to improving the resolution of the lens and ensuring the tolerance performance of the lens. The eighth lens and the ninth lens can form a double cemented lens group, which is conducive to correcting the chromatic aberration generated by the first lens to the seventh lens.

[0056] In example embodiments, the tenth lens may have negative power, an object-side surface thereof may be a concave surface, and an image-side surface thereof may be a concave surface.

[0057] In example embodiments, the eleventh lens may have positive refractive power, an object-side surface thereof may be convex, and an image-side surface thereof may be convex.

[0058] In an exemplary embodiment, the tenth lens is a negative lens, the eleventh lens is a positive lens, and the tenth lens and the eleventh lens can form a double cemented lens group. Through the coordination of the positive and negative optical power of the tenth lens and the eleventh lens and the matching of the lens shapes, the trend of light can be effectively controlled, so that the trend of light changes to a divergent trend, which is conducive to the smooth transmission of light behind the lens and helps to correct chromatic aberration. At the same time, the optical power of the tenth lens and the eleventh lens is reasonably set, and through the coordination with the eighth lens and the ninth lens, the lens distortion can be effectively corrected to achieve a low distortion effect of the lens.

[0059] In an exemplary embodiment, the twelfth lens may have positive power, and its image side surface may be convex. By setting the twelfth lens as a positive lens and its image side surface as a convex surface, it is helpful to control the trend of light, increase the ability to focus light, change the light from a divergent trend to a parallel light trend, and help reduce the generation of spherical aberration. It can also be reasonably matched with the thirteenth lens with positive power to correct system distortion and achieve a low distortion effect of the lens. As an example, the object side surface of the twelfth lens can be a concave surface, a convex surface or a plane.

[0060] In an exemplary embodiment, the thirteenth lens may have positive focal power, and its object side surface may be convex. By setting the thirteenth lens as a positive lens and its object side surface as a convex surface, it is helpful to control the trend of light, further increase the ability to focus light, change the trend of light into parallel light for transmission, help better adapt to the mobile phone lens, make the light smoothly transmitted to the optical system of the mobile phone lens, and also help correct the aberration of the optical system. As an example, the image side surface of the thirteenth lens may be a plane or a convex surface.

[0061] In an exemplary embodiment, the imaging system according to the present application may satisfy: 0.08≤f9 / f≤0.24, where f9 is the effective focal length of the ninth lens and f is the effective focal length of the imaging system. Satisfying 0.08≤f9 / f≤0.24 and reasonably controlling the focal length value of the ninth lens can effectively control the trend of light, converge the light, effectively correct spherical aberration, astigmatism and field curvature, and help improve the resolution of the lens and ensure the tolerance performance of the lens. More specifically, f9 and f can further satisfy 0.12≤f9 / f≤0.21.

[0062] In an exemplary embodiment, the imaging system according to the present application may satisfy: 0.14≤f10 / f≤0.32, wherein f10 is the effective focal length of the tenth lens, and f is the effective focal length of the imaging system. Satisfying 0.14≤f10 / f≤0.32, the focal length value of the tenth lens is reasonably controlled, and the trend of light can be effectively controlled by coordinating the positive and negative focal lengths of the tenth lens and the eleventh lens, so that the trend of light changes to a divergent trend, which is conducive to the smooth transmission of light behind the lens and helps to correct chromatic aberration. More specifically, f10 and f may further satisfy 0.17≤f10 / f≤0.3.

[0063] In an exemplary embodiment, the imaging system according to the present application may satisfy: -0.45≤f11 / f≤-0.32, wherein f11 is the effective focal length of the eleventh lens, and f is the effective focal length of the imaging system. By satisfying -0.45≤f11 / f≤-0.32 and reasonably controlling the focal length value of the eleventh lens, the trend of light can be effectively controlled by coordinating the positive and negative focal lengths of the tenth lens and the eleventh lens, so that the trend of light changes to a divergent trend, which is conducive to the smooth transmission of light behind the lens and helps to correct chromatic aberration. More specifically, f11 and f may further satisfy -0.44≤f11 / f≤-0.34.

[0064] In an exemplary embodiment, the imaging system according to the present application may satisfy: -1.35≤f13 / f≤-0.7, wherein f13 is the effective focal length of the thirteenth lens, and f is the effective focal length of the imaging system. Satisfying -1.35≤f13 / f≤-0.7 and reasonably controlling the ratio of the focal length value of the thirteenth lens to the focal length value of the imaging system can help control the trend of light, further increase the ability to focus light, and change the trend of light into parallel light for transmission, which helps to better adapt to the imaging lens, so that the light is smoothly transmitted to the optical system of the imaging lens, helps to balance aberrations and eliminate vertical axis chromatic aberration, and effectively improves illumination, ensuring that the lens group does not affect the use of the imaging lens as a main camera lens when used as an external auxiliary lens, thereby improving the imaging quality of the imaging system. More specifically, f13 and f can further satisfy -1.3≤f13 / f≤-0.72.

[0065] In an exemplary embodiment, the imaging system according to the present application may satisfy: 1.1≤fd1 / f≤1.8, wherein fd1 is the combined effective focal length of the eighth lens and the ninth lens, and f is the effective focal length of the imaging system. Satisfying 1.1≤fd1 / f≤1.8, by reasonably setting the combined effective focal length of the eighth lens and the ninth lens, the trend of light can be effectively controlled, the light can be converged, and spherical aberration, astigmatism and field curvature can be effectively corrected, which is beneficial to improving the resolution of the lens, ensuring the tolerance performance of the lens, and also helping to correct the chromatic aberration generated by the first lens to the seventh lens. In addition, the combined effective focal length of the eighth lens and the ninth lens is reasonably set so that it cooperates with the effective focal length of the tenth lens and the eleventh lens to effectively correct the lens distortion and achieve the low distortion effect of the lens. More specifically, fd1 and f can further satisfy 1.13≤fd1 / f≤1.75.

[0066] In an exemplary embodiment, the imaging system according to the present application may satisfy: 2.15≤fa / fb≤2.5, wherein fa is the combined effective focal length of the first lens to the ninth lens, and fb is the combined effective focal length of the tenth lens to the thirteenth lens. Satisfying 2.15≤fa / fb≤2.5 and rationally controlling the ratio of the combined effective focal length of the first lens to the ninth lens and the combined effective focal length of the tenth lens to the thirteenth lens is conducive to realizing the telephoto characteristics of the imaging system, while improving the angular magnification of the imaging system, so that the lens group of the imaging system can achieve an angular magnification of 2.35X when used in combination with the imaging lens. In addition, the illumination of the imaging system can be effectively improved, so that the imaging system can have a better telephoto function. More specifically, fa and fb can further satisfy 2.18≤fa / fb≤2.4.

[0067] In an exemplary embodiment, the imaging system according to the present application may satisfy: -1.80≤f1 / f≤1.42, wherein f1 is the effective focal length of the first lens, and f is the effective focal length of the imaging system. Satisfying -1.80≤f1 / f≤1.42 and rationally controlling the ratio of the effective focal length of the first lens to the effective focal length of the imaging system is beneficial to reducing the incident angle of the field light on the object side, allowing the light to better enter the imaging system, reducing the generation of aberrations and distortions, and facilitating the realization of high image quality and reduced distortion of the imaging system; at the same time, it is beneficial to cooperate with other lenses to correct chromatic aberration. More specifically, f1 and f may further satisfy -1.68≤f1 / f≤1.34.

[0068] In an exemplary embodiment, the imaging system according to the present application may satisfy: -1.40≤f2 / f≤-0.7, where f2 is the effective focal length of the second lens and f is the effective focal length of the imaging system. Satisfying -1.40≤f2 / f≤-0.7 and reasonably controlling the ratio of the effective focal length of the second lens to the effective focal length of the imaging system is conducive to reducing the generation of spherical aberration and distortion, achieving high image quality of the imaging system, and reducing distortion. More specifically, f2 and f may further satisfy -1.32≤f2 / f≤-0.73.

[0069] In an exemplary embodiment, the imaging system according to the present application may satisfy: -1.1≤f3 / f≤0.42, wherein f3 is the effective focal length of the third lens, and f is the effective focal length of the imaging system. Satisfying -1.1≤f3 / f≤0.42 and reasonably controlling the ratio of the effective focal length of the third lens to the effective focal length of the imaging system can help to diverge the light converged by the first lens and the second lens, reduce the generation of spherical aberration, and enable the third lens to better cooperate with the second lens and the fourth lens, thereby eliminating chromatic aberration, which is conducive to achieving high image quality of the lens. More specifically, f3 and f can further satisfy -1.05≤f3 / f≤0.4.

[0070] In an exemplary embodiment, the imaging system according to the present application may satisfy: -1≤f4 / f≤0.89, where f4 is the effective focal length of the fourth lens and f is the effective focal length of the imaging system. Satisfying -1≤f4 / f≤0.89 and reasonably controlling the ratio of the effective focal length of the fourth lens to the effective focal length of the imaging system can enable the fourth lens to better cooperate with the third lens, thereby eliminating chromatic aberration and reducing the generation of spherical aberration, which is conducive to achieving high image quality of the lens. More specifically, f4 and f may further satisfy -0.95≤f4 / f≤0.85.

[0071] In an exemplary embodiment, the imaging system according to the present application may satisfy: -3.8≤f5 / f≤-1.15, where f5 is the effective focal length of the fifth lens and f is the effective focal length of the imaging system. Satisfying -3.8≤f5 / f≤-1.15 and reasonably controlling the ratio of the effective focal length of the fifth lens to the effective focal length of the imaging system is conducive to controlling the incident height of the light, making the light transition smoothly, effectively reducing the tolerance sensitivity of the lens, and improving the production yield of the lens. More specifically, f5 and f may further satisfy -3.57≤f5 / f≤-1.22.

[0072] In an exemplary embodiment, the imaging system according to the present application may satisfy: 0.4≤|f6 / f|≤9, where f6 is the effective focal length of the sixth lens and f is the effective focal length of the imaging system. Satisfying 0.4≤|f6 / f|≤9 and reasonably controlling the ratio of the effective focal length of the sixth lens to the effective focal length of the imaging system is beneficial to reducing the generation of spherical aberration and improving the resolution of the lens; at the same time, it is helpful to cooperate with the seventh lens to form a cemented lens group, which can effectively control the trend of light and converge light, which is beneficial to reducing the sensitivity of lens tolerance and improving the production yield of the lens. More specifically, f6 and f may further satisfy 0.45≤|f6 / f|≤8.75.

[0073] In an exemplary embodiment, the imaging system according to the present application may satisfy: -1.7≤f7 / f≤-0.25, wherein f7 is the effective focal length of the seventh lens, and f is the effective focal length of the imaging system. Satisfying -1.7≤f7 / f≤-0.25 and reasonably controlling the ratio of the effective focal length of the seventh lens to the effective focal length of the imaging system is beneficial to reducing the generation of spherical aberration and improving the resolution of the lens; at the same time, it is helpful to cooperate with the sixth lens to form a cemented lens group, which can effectively control the trend of light and converge light, which is beneficial to reducing the sensitivity of lens tolerance and improving the production yield of the lens. More specifically, f7 and f may further satisfy -1.63≤f7 / f≤-0.3.

[0074] In an exemplary embodiment, the imaging system according to the present application may satisfy: -0.76≤f12 / f≤-0.38, wherein f12 is the effective focal length of the thirteenth lens, and f is the effective focal length of the imaging system. Satisfying -0.76≤f12 / f≤-0.38, rationally controlling the ratio of the focal length of the twelfth lens to the focal length of the imaging system, effectively controlling the trend of light, allowing the outgoing light to be smoothly transmitted, helps eliminate the chromatic aberration generated by the first lens to the eleventh lens, and reduces spherical aberration, improves the resolution quality of the lens, and further helps to achieve low distortion, making the absolute value of the optical distortion of the imaging system ≤2%. More specifically, f12 and f may further satisfy -0.7≤f12 / f≤-0.4.

[0075] In an exemplary embodiment, the imaging system according to the present application may satisfy: 0.15≤Thb / TTa≤0.4, wherein Thb is the on-axis distance from the object side of the tenth lens to the image side of the thirteenth lens, and TTa is the on-axis distance from the object side of the first lens to the image side of the thirteenth lens. Satisfying 0.15≤Thb / TTa≤0.4, rationally controlling the ratio of the on-axis distance from the object side of the tenth lens to the image side of the thirteenth lens to the on-axis distance from the object side of the first lens to the image side of the thirteenth lens, and rationally configuring the position arrangement of the tenth lens to the thirteenth lens in the imaging system lens group, is conducive to controlling the total length of the imaging system lens group, so that the imaging system can be miniaturized while meeting performance requirements. More specifically, Thb and TTa may further satisfy 0.19≤Thb / TTa≤0.35.

[0076] In an exemplary embodiment, the imaging system according to the present application may satisfy: 0.15≤Et / TTa≤0.25, wherein Et is the on-axis distance from the image side of the thirteenth lens to the aperture, and TTa is the on-axis distance from the object side of the first lens to the image side of the thirteenth lens. Satisfying 0.15≤Et / TTa≤0.25 and reasonably controlling the ratio of the on-axis distance from the image side of the thirteenth lens to the aperture to the on-axis distance from the object side of the first lens to the image side of the thirteenth lens is beneficial to controlling the rear end size of the imaging system lens group and realizing miniaturization and compactness of the imaging system.

[0077] In an exemplary embodiment, the imaging system according to the present application may satisfy: 1.9≤D1 / Ed≤2.5, where D1 is the optical full aperture of the object side of the first lens, and Ed is the full aperture of the aperture. Satisfying 1.9≤D1 / Ed≤2.5 and reasonably controlling the ratio of the optical full aperture of the object side of the first lens to the full aperture of the aperture is conducive to miniaturization of the lens, while increasing the angular magnification of the imaging system, ensuring that the lens group can achieve an angular magnification of 2.35X when used in combination with the imaging lens as an external auxiliary lens, so that the imaging system can have a better telescopic function.

[0078] In an exemplary embodiment, the imaging system according to the present application may satisfy at least one of the following: 25≤vd3≤95.2, 18≤vd5≤95.2, 18≤vd7≤35, 55≤vd13≤95.2, wherein vd3 is the Abbe number of the third lens, vd5 is the Abbe number of the fifth lens, vd7 is the Abbe number of the seventh lens, and vd13 is the Abbe number of the thirteenth lens. By properly selecting the lens materials of the third lens, the fifth lens, the seventh lens, and the thirteenth lens, the vertical axis chromatic aberration of the imaging system can be effectively corrected, the generation of purple fringing of the imaging system can be avoided, and the imaging quality can be improved. More specifically, vd3, vd5, vd7, and vd13 may further satisfy at least one of the following: 29≤vd3≤82, 22≤vd5≤82, 20≤vd7≤30, 63≤vd13≤95.2.

[0079] In an exemplary embodiment, the optical distortion DIS of the imaging system of the present application satisfies: |DIS|≤2%. The imaging system of the present application has a low optical distortion value, that is, it has the characteristics of low distortion, effectively reduces the degree of deformation of the edge of the imaging picture, and better solves the problem that the current external telephoto lens cannot obtain smaller distortion.

[0080] In an exemplary embodiment, each lens of the first lens to the thirteenth lens included in the imaging system of the present application may be a spherical lens or an aspherical lens. As needed, the present application does not specifically limit the specific number of spherical lenses and aspherical lenses. When focusing on the imaging quality, the number of aspherical lenses can be increased, and even all lenses use aspherical lenses. The characteristic of an aspherical lens is that the curvature changes continuously from the center of the lens to the periphery. Unlike a spherical lens with a constant curvature from the center of the lens to the periphery, an aspherical lens has a better curvature radius characteristic, and has the advantages of improving distortion aberration and improving astigmatism aberration. After using an aspherical lens, the aberration that occurs during imaging can be eliminated as much as possible, thereby improving the imaging quality of the lens. However, those skilled in the art should understand that without departing from the technical solution claimed for protection in the present application, the lens surface shape constituting the lens group or the imaging system can be changed to obtain the various results and advantages described in this specification. As an example, the first lens to the thirteenth lens in the present application are all spherical lenses.

[0081] Those skilled in the art should understand that the temperature coefficient of refractive index dn / dt and anomalous dispersion of plastics are relatively large. Reasonable matching of an appropriate amount of plastic material is beneficial to high and low temperature balance, but too many plastic lenses are not conducive to system stability. Optical lenses made of glass can suppress the deviation of the back focus of the optical lens with temperature changes to improve system stability; at the same time, the use of glass materials can avoid the problem of lens imaging blur caused by high and low temperature changes in the use environment, which affects the normal use of the lens. The use of glass materials is conducive to the athermalization of the lens. In addition, the use of glass materials can also better correct system chromatic aberration, improve the resolution of the lens, and reduce the generation of ghost images. As an example, the first lens to the thirteenth lens in this application are all made of glass.

[0082] The present application provides an imaging system using multiple lenses (for example, thirteen lenses). By reasonably setting the optical focal length of each lens, the imaging system can have a telephoto characteristic, reduce the optical distortion of the imaging system, improve the relative illumination of the imaging system, and improve aberration problems such as chromatic aberration and astigmatism, thereby improving the imaging quality of the imaging system, making the absolute value of optical distortion |DIS|≤2%, the vertical axis chromatic aberration less than 3.5μm, and the MTF curve of the central field of view at a frequency of 230lp / mm. The MTF curve is above 0.6 and the MTF curve in the entire field of view is above 0.2, and the relative illumination is ≥55%. At the same time, when it is adapted to an imaging lens with a focal length of 22.48mm, an angular magnification of 2.35X can be achieved, so that the imaging system has a better telescopic function.

[0083] However, it should be understood by those skilled in the art that, without departing from the technical solution claimed in the present application, the number of lenses constituting the lens group or the imaging system can be changed to obtain the various results and advantages described in this specification. For example, although thirteen lenses are described as an example in the embodiments, the lens group is not limited to including thirteen lenses. If necessary, the lens group may also include other numbers of lenses. The specific embodiments of the imaging system applicable to the above-mentioned embodiments are further described below with reference to the accompanying drawings.

[0084] Example 1

[0085] The following reference Figure 1 and Figure 2 An imaging system according to Embodiment 1 of the present application is described. Figure 1 FIG. 4 shows a schematic structural diagram of an imaging system according to Embodiment 1 of the present application. Figure 2 A schematic structural diagram of a lens group 10 included in an imaging system according to Embodiment 1 of the present application is shown.

[0086] like Figure 1As shown, the imaging system includes a lens group 10, a stop STOP and an imaging lens 20 arranged in sequence from the object side to the image side along the optical axis. Among them, the lens group 10 includes: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, a twelfth lens L12 and a thirteenth lens L13 in sequence from the object side to the image side along the optical axis. The imaging system also includes an imaging surface IMA arranged on the image side of the imaging lens 20.

[0087] The first lens L1 has positive refractive power, and its object-side surface S1 is convex, and its image-side surface S2 is convex.

[0088] The second lens L2 has positive refractive power, and its object-side surface S3 is convex, and its image-side surface S4 is convex.

[0089] The third lens L3 has negative refractive power, and its object-side surface S4 is concave and its image-side surface S5 is concave.

[0090] The fourth lens L4 has positive refractive power, and its object-side surface S5 is convex, and its image-side surface S6 is concave.

[0091] The fifth lens L5 has positive refractive power, and its object-side surface S7 is concave, and its image-side surface S8 is convex.

[0092] The sixth lens L6 has negative refractive power, and its object-side surface S9 is convex, and its image-side surface S10 is concave.

[0093] The seventh lens L7 has positive refractive power, and its object-side surface S10 is convex, and its image-side surface S11 is concave.

[0094] The eighth lens L8 has positive refractive power, and its object-side surface S12 is convex, and its image-side surface S13 is concave.

[0095] The ninth lens L9 has negative refractive power, and its object-side surface S13 is convex, and its image-side surface S14 is concave.

[0096] The tenth lens L10 has negative refractive power, and its object-side surface S15 is concave, and its image-side surface S16 is concave.

[0097] The eleventh lens L11 has positive refractive power, and its object-side surface S16 is convex and its image-side surface S17 is convex.

[0098] The twelfth lens L12 has positive refractive power, and its object-side surface S18 is concave, and its image-side surface S19 is convex.

[0099] The thirteenth lens L13 has positive refractive power, and its object-side surface S20 is convex, and its image-side surface S21 is convex.

[0100] The second lens L2, the third lens L3 and the fourth lens L4 form a triplet lens group, the sixth lens L6 and the seventh lens L7 form a doublet lens group, the eighth lens L8 and the ninth lens L9 form a doublet lens group, and the tenth lens L10 and the eleventh lens L11 form a doublet lens group.

[0101] The imaging system may further include a stop STO, which may be disposed between the thirteenth lens L13 of the lens group 10 and the imaging lens 20 included in the imaging system. Light from an object sequentially passes through the first lens L1 to the thirteenth lens L13 of the lens group 10 and each lens of the imaging lens 20, and is finally imaged on the imaging surface IMA.

[0102] The first lens L1 to the thirteenth lens L13 of the lens group 10 are all made of glass.

[0103] Table 1 shows the radius of curvature, thickness / distance, refractive index and Abbe number of each lens of the lens group 10 of Example 1, wherein the units of the radius of curvature and thickness / distance are both millimeters (mm).

[0104] Table 1

[0105]

[0106]

[0107] In this embodiment, when adapted to an imaging lens with a focal length of 22.48 mm, the total effective focal length f of the imaging system is -52.80 mm, the distance TTL from the object side surface S1 of the first lens L1 to the aperture S22 on the optical axis is 124.72 mm, and the maximum half field of view Semi-FOV of the imaging system is 7.00°.

[0108] The MTF value of the present embodiment 1 is above 0.2 in the whole field of view, and the MTF curve decreases evenly and smoothly from the center to the edge of the field of view. When the spatial frequency is 230lp / mm, the MTF curve of the center field of view is above 0.6, indicating that the imaging system has good imaging quality and good detail resolution ability; and the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength of the imaging system is controlled within -1.5μm to 1.5μm, indicating that the imaging system can well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane; at the same time, the relative illumination value of the imaging system is 56% at the maximum half field of view angle, indicating that the imaging system has good relative illumination.

[0109] Figure 3 The distortion curve of the imaging system of Example 1 is shown, which indicates the distortion magnitude values ​​corresponding to different field angles. It can be seen from the figure that the absolute value of the optical distortion of the edge field of view of Example 1 is 1.3%. Figure 3It can be seen that the imaging system provided in Example 1 has the characteristic of low distortion and can achieve good imaging quality.

[0110] Example 2

[0111] Figure 4 A schematic structural diagram of a lens group 10 included in an imaging system according to Embodiment 2 of the present application is shown.

[0112] The following references Figure 1 The imaging system includes a lens group 10, an aperture STO and an imaging lens 20 arranged in sequence from the object side to the image side along the optical axis. Figure 4 As shown, the lens group 10 includes, from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, a twelfth lens L12 and a thirteenth lens L13. The imaging system also includes an imaging surface IMA disposed on the image side of the imaging lens 20.

[0113] The first lens L1 has positive refractive power, and its object-side surface S1 is convex, and its image-side surface S2 is convex.

[0114] The second lens L2 has positive refractive power, and its object-side surface S3 is convex, and its image-side surface S4 is convex.

[0115] The third lens L3 has negative refractive power, and its object-side surface S4 is concave and its image-side surface S5 is concave.

[0116] The fourth lens L4 has positive refractive power, and its object-side surface S5 is convex, and its image-side surface S6 is concave.

[0117] The fifth lens L5 has positive refractive power, and its object-side surface S7 is concave, and its image-side surface S8 is convex.

[0118] The sixth lens L6 has negative refractive power, and its object-side surface S9 is convex, and its image-side surface S10 is concave.

[0119] The seventh lens L7 has positive refractive power, and its object-side surface S10 is convex, and its image-side surface S11 is convex.

[0120] The eighth lens L8 has positive refractive power, and its object-side surface S12 is convex, and its image-side surface S13 is concave.

[0121] The ninth lens L9 has negative refractive power, and its object-side surface S13 is convex, and its image-side surface S14 is concave.

[0122] The tenth lens L10 has negative refractive power, and its object-side surface S15 is concave, and its image-side surface S16 is concave.

[0123] The eleventh lens L11 has positive refractive power, and its object-side surface S16 is convex and its image-side surface S17 is convex.

[0124] The twelfth lens L12 has positive refractive power, and its object-side surface S18 is concave, and its image-side surface S19 is convex.

[0125] The thirteenth lens L13 has positive refractive power, and its object-side surface S20 is convex, and its image-side surface S21 is convex.

[0126] The second lens L2, the third lens L3 and the fourth lens L4 form a triplet lens group, the sixth lens L6 and the seventh lens L7 form a doublet lens group, the eighth lens L8 and the ninth lens L9 form a doublet lens group, and the tenth lens L10 and the eleventh lens L11 form a doublet lens group.

[0127] The imaging system may further include a stop STO, which may be disposed between the thirteenth lens L13 of the lens group 10 and the imaging lens 20 included in the imaging system. Light from an object sequentially passes through the first lens L1 to the thirteenth lens L13 of the lens group 10 and each lens of the imaging lens 20, and is finally imaged on the imaging surface IMA.

[0128] The first lens L1 to the thirteenth lens L13 of the lens group 10 are all made of glass.

[0129] Table 2 shows the radius of curvature, thickness / distance, refractive index and Abbe number of each lens of the lens group 10 of Example 2, wherein the units of the radius of curvature and thickness / distance are both millimeters (mm).

[0130] Table 2

[0131]

[0132] In this embodiment, when adapted to an imaging lens with a focal length of 22.48 mm, the total effective focal length f of the imaging system is -52.81 mm, the distance TTL from the object side surface S1 of the first lens L1 to the aperture S22 on the optical axis is 122.07 mm, and the maximum half field of view Semi-FOV of the imaging system is 7.10°.

[0133] The MTF value of the present embodiment 2 is above 0.2 in the whole field of view, and the MTF curve decreases evenly and smoothly from the center to the edge of the field of view. When the spatial frequency is 230lp / mm, the MTF curve of the center field of view is above 0.6, indicating that the imaging system has good imaging quality and good detail resolution capability; and the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength of the imaging system is controlled within -1μm to 3.5μm, indicating that the imaging system can perfectly correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane; at the same time, the relative illumination value of the imaging system is 55% at the maximum half field of view angle, indicating that the imaging system has good relative illumination.

[0134] Figure 5 The distortion curve of the imaging system of Example 2 is shown, which indicates the distortion values ​​corresponding to different field angles. It can be seen from the figure that the absolute value of the optical distortion of the edge field of view of Example 2 is 1.1%. Figure 5 It can be seen that the imaging system provided in Example 2 has the characteristic of low distortion and can achieve good imaging quality.

[0135] Example 3

[0136] Figure 6 A schematic structural diagram of a lens group 10 included in an imaging system according to Embodiment 3 of the present application is shown.

[0137] The following references Figure 1 The imaging system includes a lens group 10, an aperture STO and an imaging lens 20 arranged in sequence from the object side to the image side along the optical axis. Figure 6 As shown, the lens group 10 includes, from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, a twelfth lens L12 and a thirteenth lens L13. The imaging system also includes an imaging surface IMA disposed on the image side of the imaging lens 20.

[0138] The first lens L1 has positive refractive power, and its object-side surface S1 is convex, and its image-side surface S2 is convex.

[0139] The second lens L2 has positive refractive power, and its object-side surface S3 is convex, and its image-side surface S4 is convex.

[0140] The third lens L3 has negative refractive power, and its object-side surface S4 is concave and its image-side surface S5 is concave.

[0141] The fourth lens L4 has positive refractive power, and its object-side surface S5 is convex, and its image-side surface S6 is concave.

[0142] The fifth lens L5 has positive refractive power, and its object-side surface S7 is concave, and its image-side surface S8 is convex.

[0143] The sixth lens L6 has negative refractive power, and its object-side surface S9 is convex, and its image-side surface S10 is concave.

[0144] The seventh lens L7 has positive refractive power, and its object-side surface S10 is convex, and its image-side surface S11 is concave.

[0145] The eighth lens L8 has positive refractive power, and its object-side surface S12 is convex, and its image-side surface S13 is concave.

[0146] The ninth lens L9 has negative refractive power, and its object-side surface S13 is convex, and its image-side surface S14 is concave.

[0147] The tenth lens L10 has negative refractive power, and its object-side surface S15 is concave, and its image-side surface S16 is concave.

[0148] The eleventh lens L11 has positive refractive power, and its object-side surface S16 is convex and its image-side surface S17 is convex.

[0149] The twelfth lens L12 has positive refractive power, and its object-side surface S18 is concave, and its image-side surface S19 is convex.

[0150] The thirteenth lens L13 has positive refractive power, and its object-side surface S20 is convex, and its image-side surface S21 is convex.

[0151] The second lens L2, the third lens L3 and the fourth lens L4 form a triplet lens group, the sixth lens L6 and the seventh lens L7 form a doublet lens group, the eighth lens L8 and the ninth lens L9 form a doublet lens group, and the tenth lens L10 and the eleventh lens L11 form a doublet lens group.

[0152] The imaging system may further include a stop STO, which may be disposed between the thirteenth lens L13 of the lens group 10 and the imaging lens 20 included in the imaging system. Light from an object sequentially passes through the first lens L1 to the thirteenth lens L13 of the lens group 10 and each lens of the imaging lens 20, and is finally imaged on the imaging surface IMA.

[0153] The first lens L1 to the thirteenth lens L13 of the lens group 10 are all made of glass.

[0154] Table 3 shows the radius of curvature, thickness / distance, refractive index and Abbe number of each lens of the lens group 10 of Example 3, wherein the units of the radius of curvature and thickness / distance are both millimeters (mm).

[0155] Table 3

[0156]

[0157] In this embodiment, when adapted to an imaging lens with a focal length of 22.48 mm, the total effective focal length f of the imaging system is -50.12 mm, the distance TTL from the object side surface S1 of the first lens L1 to the aperture S22 on the optical axis is 130.01 mm, and the maximum half field of view Semi-FOV of the imaging system is 7.10°.

[0158] The MTF value of the present embodiment 3 is above 0.2 in the whole field of view, and the MTF curve decreases evenly and smoothly from the center to the edge of the field of view. When the spatial frequency is 230lp / mm, the MTF curve of the center field of view is above 0.6, indicating that the imaging system has good imaging quality and good detail resolution capability; and the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength of the imaging system is controlled within -0.5μm to 3μm, indicating that the imaging system can well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane; at the same time, the relative illumination value of the imaging system at the maximum half field of view is 71%, indicating that the imaging system has good relative illumination.

[0159] Figure 7 The distortion curve of the imaging system of Example 3 is shown, which indicates the distortion magnitude values ​​corresponding to different field angles. It can be seen from the figure that the absolute value of the optical distortion of the edge field of view of Example 3 is 0.3%. Figure 7 It can be seen that the imaging system provided in Example 3 has the characteristic of low distortion and can achieve good imaging quality.

[0160] Example 4

[0161] Figure 8 A schematic structural diagram of a lens group 10 included in an imaging system according to Embodiment 4 of the present application is shown.

[0162] The following references Figure 1 The imaging system includes a lens group 10, an aperture STO and an imaging lens 20 arranged in sequence from the object side to the image side along the optical axis. Figure 8 As shown, the lens group 10 includes, from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, a twelfth lens L12 and a thirteenth lens L13. The imaging system also includes an imaging surface IMA disposed on the image side of the imaging lens 20.

[0163] The first lens L1 has negative refractive power, and its object-side surface S1 is convex, and its image-side surface S2 is concave.

[0164] The second lens L2 has positive refractive power, and its object-side surface S2 is convex, and its image-side surface S3 is convex.

[0165] The third lens L3 has positive refractive power, and its object-side surface S4 is convex and its image-side surface S5 is convex.

[0166] The fourth lens L4 has negative refractive power, and its object-side surface S5 is concave, and its image-side surface S6 is convex.

[0167] The fifth lens L5 has positive refractive power, and its object-side surface S7 is convex, and its image-side surface S8 is convex.

[0168] The sixth lens L6 has positive refractive power, and its object-side surface S9 is concave, and its image-side surface S10 is convex.

[0169] The seventh lens L7 has positive refractive power, and its object-side surface S11 is convex, and its image-side surface S12 is concave.

[0170] The eighth lens L8 has positive refractive power, and its object-side surface S13 is convex, and its image-side surface S14 is concave.

[0171] The ninth lens L9 has negative refractive power, and its object-side surface S14 is convex, and its image-side surface S15 is concave.

[0172] The tenth lens L10 has negative refractive power, and its object-side surface S16 is a concave surface, and its image-side surface S17 is a concave surface.

[0173] The eleventh lens L11 has positive refractive power, and its object-side surface S17 is convex and its image-side surface S18 is convex.

[0174] The twelfth lens L12 has positive refractive power, and its object-side surface S19 is convex, and its image-side surface S20 is convex.

[0175] The thirteenth lens L13 has positive refractive power, and its object-side surface S21 is convex, and its image-side surface S22 is convex.

[0176] The first lens L1 and the second lens L2 form a doublet lens group, the third lens L3 and the fourth lens L4 form a doublet lens group, the eighth lens L8 and the ninth lens L9 form a doublet lens group, and the tenth lens L10 and the eleventh lens L11 form a doublet lens group.

[0177] The imaging system may further include a stop STO, which may be disposed between the thirteenth lens L13 of the lens group 10 and the imaging lens 20 included in the imaging system. Light from an object sequentially passes through the first lens L1 to the thirteenth lens L13 of the lens group 10 and each lens of the imaging lens 20, and is finally imaged on the imaging surface IMA.

[0178] The first lens L1 to the thirteenth lens L13 of the lens group 10 are all made of glass.

[0179] Table 4 shows the radius of curvature, thickness / distance, refractive index and Abbe number of each lens of the lens group 10 of Example 4, wherein the units of the radius of curvature and thickness / distance are both millimeters (mm).

[0180] Table 4

[0181]

[0182]

[0183] In this embodiment, when adapted to an imaging lens with a focal length of 22.48 mm, the total effective focal length f of the imaging system is -52.90 mm, the distance TTL from the object side surface S1 of the first lens L1 to the aperture S23 on the optical axis is 141.71 mm, and the maximum half field of view Semi-FOV of the imaging system is 7.10°.

[0184] The MTF value of the present embodiment 4 is above 0.2 in the whole field of view, and the MTF curve decreases evenly and smoothly from the center to the edge of the field of view. When the spatial frequency is 230lp / mm, the MTF curve of the center field of view is above 0.6, indicating that the imaging system has good imaging quality and good detail resolution capability; and the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength of the imaging system is controlled within -2μm to 2μm, indicating that the imaging system can well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane; at the same time, the relative illumination value of the imaging system is 55% at the maximum half field of view angle, indicating that the imaging system has good relative illumination.

[0185] Fig. 9 The distortion curve of the imaging system of Example 4 is shown, which indicates the distortion magnitude values ​​corresponding to different field angles. It can be seen from the figure that the absolute value of the optical distortion of the edge field of view of Example 4 is 2%. Fig. 9 It can be seen that the imaging system provided in Example 4 has the characteristic of low distortion and can achieve good imaging quality.

[0186] Example 5

[0187] Fig.10 A schematic structural diagram of a lens group 10 included in an imaging system according to Embodiment 5 of the present application is shown.

[0188] The following references Figure 1 The imaging system includes a lens group 10, an aperture STO and an imaging lens 20 arranged in sequence from the object side to the image side along the optical axis. Fig.10As shown, the lens group 10 includes, from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, a twelfth lens L12 and a thirteenth lens L13. The imaging system also includes an imaging surface IMA disposed on the image side of the imaging lens 20.

[0189] The first lens L1 has negative refractive power, and its object-side surface S1 is convex, and its image-side surface S2 is concave.

[0190] The second lens L2 has positive refractive power, an object-side surface S2 thereof is convex, and an image-side surface S3 thereof is concave.

[0191] The third lens L3 has positive refractive power, and its object-side surface S4 is convex and its image-side surface S5 is convex.

[0192] The fourth lens L4 has negative refractive power, and its object-side surface S5 is concave, and its image-side surface S6 is concave.

[0193] The fifth lens L5 has positive refractive power, and its object-side surface S7 is convex, and its image-side surface S8 is convex.

[0194] The sixth lens L6 has positive refractive power, and its object-side surface S9 is concave, and its image-side surface S10 is convex.

[0195] The seventh lens L7 has positive refractive power, and its object-side surface S11 is convex, and its image-side surface S12 is concave.

[0196] The eighth lens L8 has positive refractive power, and its object-side surface S13 is convex, and its image-side surface S14 is concave.

[0197] The ninth lens L9 has negative refractive power, and its object-side surface S14 is convex, and its image-side surface S15 is concave.

[0198] The tenth lens L10 has negative refractive power, and its object-side surface S16 is a concave surface, and its image-side surface S17 is a concave surface.

[0199] The eleventh lens L11 has positive refractive power, and its object-side surface S17 is convex, and its image-side surface S28 is convex.

[0200] The twelfth lens L12 has positive refractive power, and its object-side surface S19 is concave, and its image-side surface S20 is convex.

[0201] The thirteenth lens L13 has positive refractive power, and its object-side surface S21 is convex, and its image-side surface S22 is convex.

[0202] The first lens L1 and the second lens L2 form a doublet lens group, the third lens L3 and the fourth lens L4 form a doublet lens group, the eighth lens L8 and the ninth lens L9 form a doublet lens group, and the tenth lens L10 and the eleventh lens L11 form a doublet lens group.

[0203] The imaging system may further include a stop STO, which may be disposed between the thirteenth lens L13 of the lens group 10 and the imaging lens 20 included in the imaging system. Light from an object sequentially passes through the first lens L1 to the thirteenth lens L13 of the lens group 10 and each lens of the imaging lens 20, and is finally imaged on the imaging surface IMA.

[0204] The first lens L1 to the thirteenth lens L13 of the lens group 10 are all made of glass.

[0205] Table 5 shows the radius of curvature, thickness / distance, refractive index and Abbe number of each lens of the lens group 10 of Example 5, wherein the units of the radius of curvature and thickness / distance are both millimeters (mm).

[0206] Table 5

[0207]

[0208]

[0209] In this embodiment, when adapted to an imaging lens with a focal length of 22.48 mm, the total effective focal length f of the imaging system is -52.92 mm, the distance TTL from the object side surface S1 of the first lens L1 to the aperture S23 on the optical axis is 142.03 mm, and the maximum half field of view Semi-FOV of the imaging system is 7.10°.

[0210] The MTF value of this embodiment 5 is above 0.2 in the whole field of view, and the MTF curve decreases evenly and smoothly from the center to the edge of the field of view. When the spatial frequency is 230lp / mm, the MTF curve of the center field of view is above 0.6, indicating that the imaging system has good imaging quality and good detail resolution ability; and the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength of the imaging system is controlled within -0.5μm to 3.5μm, indicating that the imaging system can well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane; at the same time, the relative illumination value of the imaging system is 55% at the maximum half field of view angle, indicating that the imaging system has good relative illumination.

[0211] Fig.11 The distortion curve of the imaging system of Example 5 is shown, which indicates the distortion values ​​corresponding to different field angles. It can be seen from the figure that the absolute value of the optical distortion of the edge field of view of Example 4 is 1.7%. Fig.11It can be seen that the imaging system provided in Example 5 has the characteristic of low distortion and can achieve good imaging quality.

[0212] In summary, Examples 1 to 5 respectively satisfy the relationship shown in Table 6 below.

[0213] Table 6

[0214]

[0215]

[0216] The present application also provides an electronic device, which may include any imaging system according to the above embodiments of the present application. The electronic device provided by the present application may be an image acquisition device, an imaging element for converting an optical image formed by the imaging system into an electrical signal.

[0217] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. An imaging system, characterized in that The imaging system includes, in order from the object side to the image side, a first lens having optical power, a second lens having positive optical power, a third lens having optical power, a fourth lens having optical power, a fifth lens having positive optical power, a sixth lens having optical power, a seventh lens having positive optical power, an eighth lens having positive optical power, a ninth lens having negative optical power, a tenth lens having negative optical power, an eleventh lens having positive optical power, a twelfth lens having positive optical power and a thirteenth lens having positive optical power; wherein the positive and negative properties of the optical power of the first lens and the third lens are opposite, and the positive and negative properties of the optical power of the third lens and the fourth lens are opposite, and the number of lenses having optical power in the imaging system is thirteen.

2. The imaging system according to claim 1, characterized in that The object side surface of the first lens is a convex surface; The object side surface of the second lens is a convex surface; The object side surface of the third lens is concave, and the image side surface is concave; or, The object side surface of the third lens is convex, and the image side surface is convex; The object side surface of the fourth lens is convex or concave; The object side surface of the fifth lens is convex or concave, and the image side surface is convex; The object side surface of the sixth lens is convex, and the image side surface is concave; or, The object side surface of the sixth lens is a concave surface, and the image side surface is a convex surface; The object side surface of the seventh lens is a convex surface; The object side surface of the eighth lens is convex, and the image side surface is concave; The object side surface of the ninth lens is convex, and the image side surface is concave; The object side surface and the image side surface of the tenth lens are both concave surfaces; The object side surface and the image side surface of the eleventh lens are both convex surfaces; The image side surface of the twelfth lens is a convex surface; The object-side surface and the image-side surface of the thirteenth lens are both convex surfaces.

3. The imaging system according to any one of claims 1 to 2, characterized in that: The imaging system satisfies: 0.08≤f9 / f≤0.24, wherein f9 is the effective focal length of the ninth lens, and f is the effective focal length of the imaging system.

4. The imaging system according to any one of claims 1 to 2, characterized in that: The imaging system satisfies at least one of the following conditions: 0.14≤f10 / f≤0.32, -0.45≤f11 / f≤-0.32, wherein f10 is the effective focal length of the tenth lens, f11 is the effective focal length of the eleventh lens, and f is the effective focal length of the imaging system.

5. The imaging system according to any one of claims 1 to 2, characterized in that: The imaging system satisfies: -1.35≤f13 / f≤-0.7, wherein f13 is the effective focal length of the thirteenth lens, and f is the effective focal length of the imaging system.

6. The imaging system according to any one of claims 1 to 2, characterized in that: The imaging system satisfies: 1.1≤fd1 / f≤1.8, wherein fd1 is the combined effective focal length of the eighth lens and the ninth lens, and f is the effective focal length of the imaging system.

7. The imaging system according to any one of claims 1 to 2, characterized in that: The imaging system satisfies: 2.15≤fa / fb≤2.5, wherein fa is the combined effective focal length of the first lens to the ninth lens, and fb is the combined effective focal length of the tenth lens to the thirteenth lens.

8. The imaging system according to any one of claims 1 to 2, characterized in that: The imaging system further includes an aperture and an imaging lens located on the image side of the thirteenth lens, the aperture is arranged between the image side surface of the thirteenth lens and the imaging lens, the imaging lens includes a plurality of lenses, and the imaging system satisfies at least one of the following conditional expressions: 0.15≤Thb / TTa≤0.4, 0.15≤Et / TTa≤0.25, 1.9≤D1 / Ed≤2.5, wherein Thb is the axial distance from the object side of the tenth lens to the image side of the thirteenth lens, TTa is the axial distance from the object side of the first lens to the image side of the thirteenth lens, Et is the axial distance from the image side of the thirteenth lens to the aperture, D1 is the optical full aperture of the object side of the first lens, and Ed is the full aperture of the aperture.

9. The imaging system according to any one of claims 1 to 2, characterized in that: The imaging system satisfies at least one of the following conditions: -1.80≤f1 / f≤1.42, -1.40≤f2 / f≤-0.7, -1.1≤f3 / f≤0.42, -1≤f4 / f≤0.89, -3.8≤f5 / f≤-1.15, 0.4≤|f6 / f|≤9, -1.7≤f7 / f≤-0.25, -0.76≤f12 / f≤-0.38, wherein f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, f6 is the effective focal length of the sixth lens, f7 is the effective focal length of the seventh lens, f12 is the effective focal length of the twelfth lens, and f is the effective focal length of the imaging system.

10. The imaging system according to any one of claims 1 to 2, characterized in that: The imaging system satisfies at least one of the following conditional expressions: 25≤vd3≤95.2, 18≤vd5≤95.2, 18≤vd7≤35, 55≤vd13≤95.2, wherein vd3 is the Abbe number of the third lens, vd5 is the Abbe number of the fifth lens, vd7 is the Abbe number of the seventh lens, and vd13 is the Abbe number of the thirteenth lens.

11. The imaging system according to any one of claims 1 to 2, wherein the imaging system satisfies at least one of the following conditions: -1.68≤f1 / f≤1.34, -1.32≤f2 / f≤-0.73, -1.05≤f3 / f≤0.4, -0.95≤f4 / f≤0.85, -3.57≤f 5 / f≤-1.22, 0.45≤|f6 / f|≤8.75, -1.63≤f7 / f≤-0.3, 0.12≤f9 / f≤0.21, 0.17≤f10 / f≤0.3 , -0.44≤f11 / f≤-0.34, -0.7≤f12 / f≤-0.4, -1.3≤f13 / f≤-0.72, 1.13≤fd1 / f≤1.75, 2.18≤fa / fb≤2.4, 0.19≤Thb / TTa≤0.35, 29≤vd3≤82, 22≤vd5≤82, 20≤vd7≤30, 63≤vd13≤95.2, in, f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, f6 is the effective focal length of the sixth lens, f7 is the effective focal length of the seventh lens, f9 is the effective focal length of the ninth lens, f10 is the effective focal length of the tenth lens, f11 is the effective focal length of the eleventh lens, f12 is the effective focal length of the twelfth lens, f13 is the effective focal length of the thirteenth lens, and f is the effective focal length of the imaging system. effective focal length, fd1 is the combined effective focal length of the eighth lens and the ninth lens, fa is the combined effective focal length of the first lens to the ninth lens, fb is the combined effective focal length of the tenth lens to the thirteenth lens, Thb is the axial distance from the object side of the tenth lens to the image side of the thirteenth lens, TTa is the axial distance from the object side of the first lens to the image side of the thirteenth lens, vd3 is the Abbe number of the third lens, vd5 is the Abbe number of the fifth lens, vd7 is the Abbe number of the seventh lens, and vd13 is the Abbe number of the thirteenth lens.

Images