Imaging system, lens module and electronic equipment

Abstract

The present application discloses an imaging system, a lens module and an electronic device, belonging to the technical field of optical imaging; along the optical axis from the object plane to the image plane, it sequentially includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens. The imaging system satisfies the following conditional formula: -19.5mm < f4*f5 / f < -4mm, where f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, and f is the focal length of the imaging system. By reasonably defining the focal length of the fourth lens and the focal length of the imaging system, the embodiments of the present application can improve the imaging quality and ensure high pixels and a large depth of field.

Description

Technical Field

[0001] The present application relates to the field of optical imaging technology, and in particular to an imaging system, a lens module and an electronic device. Background Art

[0002] With the continuous development of automotive technology (such as assisted driving technology, automatic driving and unmanned driving) and the increasing demand for car driving safety, the application of vehicle-mounted cameras is becoming more and more popular. Vehicle-mounted cameras can observe images from a long distance, grasp the intersection ahead in real time, and provide guarantee for safe driving.

[0003] However, existing vehicle-mounted cameras require long-distance object capture and observation, the overall pixel is difficult to guarantee, and the depth of field is small. Summary of the invention

[0004] The embodiment of the present application provides an imaging system, a lens module and an electronic device, which can improve the imaging quality, ensure high pixels and a large depth of field. The technical solution is as follows:

[0005] In a first aspect, an embodiment of the present application provides an imaging system, which includes, in sequence from the object plane to the image plane along the optical axis:

[0006] A first lens, wherein the first lens has negative refractive power, and an object side surface of the first lens is convex at a near optical axis;

[0007] A second lens, wherein the second lens has negative refractive power, and an object side surface of the second lens is concave at a near optical axis;

[0008] A third lens, the third lens has positive refractive power, and the object side surface of the third lens is convex at the near optical axis;

[0009] a fourth lens having positive refractive power, an object-side surface of the fourth lens being convex at the near optical axis, and an image-side surface of the fourth lens being convex at the near optical axis;

[0010] a fifth lens having negative refractive power, wherein the object side surface of the fifth lens is concave at a near optical axis;

[0011] a sixth lens having positive refractive power, wherein the object side surface of the sixth lens is a convex surface near the optical axis;

[0012] a seventh lens having negative refractive power, and an object-side surface of the seventh lens being convex near the optical axis;

[0013] Wherein, the imaging system satisfies the following conditional formula:

[0014] -19.5mm <f 4 *f 5 / f<-4mm;

[0015] Among them, f 4 is the focal length of the fourth lens, f 5 is the focal length of the fifth lens, and f is the focal length of the imaging system.

[0016] The imaging system of the embodiment of the present application can improve the imaging quality and ensure high pixel and large depth of field by reasonably designing the refractive power and surface shape of the first lens to the seventh lens. By reasonably limiting the focal length of the fourth lens, the focal length of the fifth lens and the focal length of the imaging system, it is helpful to correct the aberration caused by the refracting of the light through the front lens, improve the resolution of the imaging system, and by satisfying the relationship condition, it is helpful to reduce the angle of the light emitted from the imaging system after being refracted by the lens group, and improve the high-quality imaging picture of the imaging system.

[0017] In some embodiments, the imaging system further satisfies the following condition:

[0018] -8 <f 1 / f<-4;

[0019] Among them, f 1 is the focal length of the first lens.

[0020] Based on the above embodiment, by reasonably limiting the focal length of the first lens and the focal length of the imaging system, it is possible to capture light that enters the imaging system at a large angle and expand the field of view of the imaging system. 1 When f1 / f≥-4, the refractive power of the first lens is too strong, and the image on the image plane will be sensitive to the changes of the first lens, resulting in large aberrations; when f1 / f≤-8, the refractive power of the first lens is insufficient, which is not conducive to large-angle light entering the imaging system.

[0021] In some embodiments, the imaging system further satisfies the following condition:

[0022] -5 <f 2 / f<-1;

[0023] Among them, f 2 is the focal length of the second lens.

[0024] Based on the above embodiments, by reasonably limiting the focal length of the second lens and the focal length of the imaging system, it is beneficial to widen the light width, so that the light captured by the large-angle light after refraction by the first lens is widened, fills the pupil, and is fully transmitted to the imaging surface, thereby obtaining a wider field of view, which is beneficial to reflecting the high-pixel characteristics of the imaging system.

[0025] In some embodiments, the imaging system further satisfies the following condition:

[0026] 8 <SD S3 / SAG S3 <25;

[0027] Among them, SD S3 is the maximum effective aperture of the object side of the second lens, SAG S3 is the sagittal height of the object side of the second lens at the maximum effective radius.

[0028] Based on the above embodiment, by reasonably limiting the maximum effective clear aperture of the object side of the second lens and the sagittal height of the object side of the second lens at the maximum effective radius, the problem of excessive curvature of the object side of the second lens resulting in uneven coating can be avoided, the difficulty of processing the second lens can be reduced, and it is beneficial for large-angle light to be incident on the imaging system, thereby improving the imaging quality of the imaging system. S3 / SAG S3 When SD is ≥25, the side of the second lens will be too smooth, which may cause ghosting. S3 / SAG S3 When ≤8, the object side surface of the second lens will be too curved, which will increase the difficulty of processing the second lens, making it difficult to shape and resulting in low manufacturing yield.

[0029] In some embodiments, the imaging system further satisfies the following condition:

[0030] 3 <CT 3 / SAG S5 <23.5;

[0031] Among them, CT 3 is the thickness of the third lens on the optical axis, SAG S5 is the sagittal height of the object side of the third lens at the maximum effective radius.

[0032] Based on the above embodiment, by reasonably limiting the thickness of the third lens on the optical axis and the sagittal height of the object side of the third lens at the maximum effective radius, it is possible to avoid the third lens having an excessively large central thickness or an excessively curved object side, thereby reducing the difficulty of lens manufacturing, improving the manufacturing yield, and thus helping to reduce production costs. 3 / SAG S5 ≥23.5, the thickness of the third lens is too large, which is not conducive to the lightweight and miniaturization of the imaging lens. 3 / SAG S5 When ≤3, the object side of the third lens is too curved, and the lens processing difficulty increases; at the same time, the surface is too curved, which is prone to edge aberration, which is not conducive to improving the image quality of the optical system.

[0033] In some embodiments, the imaging system further satisfies the following condition:

[0034] -31mm 2 <f 6 *f 7 <-9mm 2 ;

[0035] Among them, f 6 is the focal length of the sixth lens, f 7 is the focal length of the seventh lens.

[0036] Based on the above embodiments, by reasonably limiting the focal lengths of the sixth lens element and the seventh lens element, it is beneficial to further eliminate aberrations and correct the astigmatism phenomenon caused by the refracting of light through the front lens group.

[0037] In some embodiments, the imaging system further satisfies the following condition:

[0038] 13.5<(Nd 5 -Nd 4 )*100<23;

[0039] Among them, Nd 5 is the d-light refractive index of the fifth lens, Nd 4 is the d-light refractive index of the fourth lens element.

[0040] Based on the above embodiment, by reasonably limiting the refractive index of the fifth lens and the refractive index of the fourth lens, it is beneficial to optimize the aberration and improve the imaging resolution. 5 -Nd 4 )*100≥23 or (Nd 5 -Nd 4 )*100≤13.5, it is not conducive to the correction of the aberration of the imaging system, thereby reducing the imaging quality.

[0041] In some embodiments, the imaging system further satisfies the following condition:

[0042] 3.5 <TTL / DOS<6;

[0043] Wherein, TTL is the distance from the object side surface of the first lens to the image plane on the optical axis, and DOS is the distance from the object side surface of the first lens to the aperture on the optical axis.

[0044] Based on the above embodiment, by reasonably limiting the distance from the object side of the first lens to the image plane near the optical axis and the distance from the object side of the first lens to the aperture near the optical axis, the imaging system is compact and miniaturized. When TTL / DOS≥6, the total optical length of the imaging system is too long, which is not conducive to the miniaturization of the imaging system. When TTL / DOS≤3.5, it is difficult for a large-angle light beam to enter the imaging system, which reduces the imaging range of the object space of the imaging lens and is not conducive to achieving wide-angle.

[0045] In a second aspect, an embodiment of the present application provides a lens module, including:

[0046] Lens tube;

[0047] An imaging system as described above, wherein the imaging system is disposed in the lens barrel;

[0048] A photosensitive element is arranged on the image side of the imaging system.

[0049] Based on the lens module in the embodiment of the present application, by reasonably designing the refractive power and surface shape of the first lens to the seventh lens, it is possible to improve the imaging quality, ensure high pixels and a large depth of field. By reasonably limiting the focal length of the fourth lens, the focal length of the fifth lens and the focal length of the imaging system, it is helpful to correct the aberration caused by the refracting of the light through the front lens, improve the resolution of the imaging system, and by satisfying the relationship condition, it is helpful to reduce the angle of the light emitted from the imaging system after being refracted by the lens group, and improve the high-quality imaging picture of the imaging system.

[0050] In a third aspect, an embodiment of the present application provides an electronic device, including:

[0051] housing; and

[0052] The above-mentioned lens module is arranged in the shell.

[0053] Based on the electronic device in the embodiment of the present application, by reasonably designing the refractive power and surface shape of the first lens to the seventh lens, it is possible to improve the imaging quality, ensure high pixels and a large depth of field. By reasonably limiting the focal length of the fourth lens, the focal length of the fifth lens and the focal length of the imaging system, it is helpful to correct the aberration caused by the refracting of the light through the front lens, improve the resolution of the imaging system, and by satisfying the relationship condition, it is helpful to reduce the angle of the light emitted from the imaging system after being refracted by the lens group, and improve the high-quality imaging picture of the imaging system. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0055] Figure 1 is a schematic diagram of the structure of an imaging system provided in Embodiment 1 of the present application;

[0056] Figure 2 It is a longitudinal spherical aberration curve diagram, an astigmatism curve diagram, and a distortion curve diagram of the imaging system provided in Example 1 of the present application;

[0057] Figure 3 is a schematic diagram of the structure of an imaging system provided in Embodiment 2 of the present application;

[0058] Figure 4 It is a longitudinal spherical aberration curve diagram, an astigmatism curve diagram, and a distortion curve diagram of the imaging system provided in the second embodiment of the present application;

[0059] Figure 5 is a schematic diagram of the structure of an imaging system provided in Embodiment 3 of the present application;

[0060] Figure 6 It is a longitudinal spherical aberration curve diagram, an astigmatism curve diagram, and a distortion curve diagram of the imaging system provided in Example 3 of the present application;

[0061] Figure 7 is a schematic diagram of the structure of an imaging system provided in Embodiment 4 of the present application;

[0062] Figure 8 The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the imaging system provided in the fourth embodiment of the present application are shown in FIG.

[0063] Fig. 9 is a schematic diagram of the structure of an imaging system provided in Embodiment 5 of the present application;

[0064] Fig.10 It is a longitudinal spherical aberration curve diagram, an astigmatism curve diagram, and a distortion curve diagram of the imaging system provided in Example 5 of the present application;

[0065] Fig.11 is a schematic diagram of the structure of an imaging system provided in Example 6 of the present application;

[0066] Fig.12 These are the longitudinal spherical aberration curve diagram, astigmatism curve diagram, and distortion curve diagram of the imaging system provided in Example 6 of the present application. DETAILED DESCRIPTION

[0067] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0068] With the continuous development of automotive technology (such as assisted driving technology, automatic driving and unmanned driving) and the improvement of people's requirements for automobile driving safety, the application of vehicle-mounted cameras has become more and more popular. Vehicle-mounted cameras can observe images beyond a long distance, grasp the intersection ahead in real time, and provide protection for safe driving. However, due to the characteristics of existing vehicle-mounted cameras in capturing and observing objects at a long distance, the overall pixel is difficult to guarantee, and the depth of field is small. Based on this, the embodiments of the present application provide an imaging system, a lens module and an electronic device, which are intended to solve the above technical problems.

[0069] In a first aspect, the embodiments of the present application provide an imaging system, which includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160 and a seventh lens 170 in sequence from the object plane to the image plane along the optical axis.

[0070] The first lens 110 has a negative refractive power, and the object side surface of the first lens 110 is a convex surface at the near optical axis. The second lens 120 has a negative refractive power, and the object side surface of the second lens 120 is a concave surface at the near optical axis. The third lens 130 has a positive refractive power, and the object side surface of the third lens 130 is a convex surface at the near optical axis. The fourth lens 140 has a positive refractive power, and the object side surface of the fourth lens 140 is a convex surface at the near optical axis, and the image side surface of the fourth lens 140 is a convex surface at the near optical axis. The fifth lens 150 has a negative refractive power, and the object side surface of the fifth lens 150 is a concave surface at the near optical axis. The sixth lens 160 has a positive refractive power, and the object side surface of the sixth lens 160 is a convex surface at the near optical axis. The seventh lens 170 has a negative refractive power, and the object side surface of the seventh lens 170 is a convex surface at the near optical axis.

[0071] The imaging system satisfies the following condition: -19.5 mm <f 4 *f 5 / f<-4mm, where f 4 is the focal length of the fourth lens 140, f 5 is the focal length of the fifth lens 150, and f is the focal length of the imaging system.

[0072] The imaging system of the embodiment of the present application can improve the imaging quality, ensure high pixel and large depth of field by reasonably designing the refractive power and surface shape of the first lens 110 to the seventh lens 170. By reasonably limiting the focal length of the fourth lens 140, the focal length of the fifth lens 150 and the focal length of the imaging system, it is helpful to correct the aberration caused by the refracting of the light through the front lens, improve the resolution of the imaging system, and by satisfying the relationship condition, it is helpful to reduce the angle of the light emitted from the imaging system after being refracted by the lens group, and improve the high-quality imaging picture of the imaging system.

[0073] In order to realize the miniaturization feature of the lens and facilitate the correction of chromatic aberration, the fourth lens 140 and the fifth lens 150 are cemented together.

[0074] The imaging system also satisfies the following condition: <f 1 / f<-4, where f 1 is the focal length of the first lens 110, and f is the focal length of the imaging system. Based on the above embodiment, by reasonably limiting the focal length of the first lens 110 and the focal length of the imaging system, it is possible to capture light that enters the imaging system at a large angle and expand the field of view of the imaging system. 1 / f≥-4, the refractive power of the first lens 110 is too strong, and the image plane image will be sensitive to the change of the first lens 110, thereby generating a large aberration; when f 1 When / f≤-8, the refractive power of the first lens 110 is insufficient, which is not conducive to large-angle light entering the imaging system.

[0075] The imaging system also satisfies the following condition: <f 2 / f<-1, where f 2 is the focal length of the second lens 120, and f is the focal length of the imaging system. Based on the above embodiment, by reasonably limiting the focal length of the second lens 120 and the focal length of the imaging system, it is beneficial to widen the light width, so that the light of large angle light refracted by the first lens 110 is widened, fills the pupil, and is fully transmitted to the imaging surface, thereby obtaining a wider field of view, which is beneficial to reflecting the high pixel characteristics of the imaging system.

[0076] The imaging system also satisfies the following condition: <SD S3 / SAG S3 <25, where SD S3 is the maximum effective aperture of the object side of the second lens 120, SAG S3is the sagittal height of the object side surface of the second lens 120 at the maximum effective radius. It should be noted that the sagittal height is the distance from the intersection of the object side surface of the second lens 120 and the optical axis to the maximum effective aperture of the surface (i.e., the maximum effective radius of the surface) in the direction parallel to the optical axis; when the value is positive, the maximum effective aperture of the surface is closer to the image side of the imaging system than the center of the surface in the direction parallel to the optical axis of the imaging system; when the value is negative, the maximum effective aperture of the surface is closer to the object side of the imaging system than the center of the surface in the direction parallel to the optical axis of the imaging system.

[0077] Based on the above embodiment, by reasonably limiting the maximum effective light aperture of the object side of the second lens 120 and the sagittal height of the object side of the second lens 120 at the maximum effective radius, the problem of excessive curvature of the object side of the second lens 120 resulting in uneven coating can be avoided, and the processing difficulty of the second lens 120 can be reduced. The second lens 120 is conducive to large-angle light incident on the imaging system, thereby improving the imaging quality of the imaging system. S4 / SAG S3 When SD is ≥25, the object side of the second lens 120 will be too smooth, which may cause ghosting. S4 / SAG S3 ≤8, the object side of the second lens will be too curved, which will increase the difficulty of processing the second lens, making it difficult to shape and resulting in a low manufacturing yield.

[0078] The imaging system also satisfies the following condition: 0.5 <f 3 / f<1, where f 3 is the focal length of the third lens 130, and f is the focal length of the imaging system. Based on the above embodiment, by reasonably limiting the focal length of the third lens 130 and the focal length of the imaging system, it is beneficial to correct edge aberrations and improve imaging resolution. 3 / f≥1 or f 3 When / f≤0.5, it is not conducive to the correction of the aberration of the imaging system, thereby reducing the imaging quality.

[0079] The imaging system also satisfies the following condition: <CT 3 / SAG S5 <23.5, of which CT 3 is the thickness of the third lens 130 on the optical axis, SAG S5is the sagittal height of the object side surface of the third lens 130 at the maximum effective radius. It should be noted that the sagittal height is the distance from the intersection of the object side surface of the third lens 130 and the optical axis to the maximum effective aperture of the surface (i.e., the maximum effective radius of the surface) in the direction parallel to the optical axis; when the value is positive, the maximum effective aperture of the surface is closer to the image side of the imaging system than the center of the surface in the direction parallel to the optical axis of the imaging system; when the value is negative, the maximum effective aperture of the surface is closer to the object side of the imaging system than the center of the surface in the direction parallel to the optical axis of the imaging system.

[0080] Based on the above embodiment, by reasonably limiting the thickness of the third lens 130 on the optical axis and the sagittal height of the object side of the third lens 130 at the maximum effective radius, it is avoided that the central thickness of the third lens 130 is too large or the object side is too curved, which reduces the difficulty of lens manufacturing, improves the manufacturing yield, and is conducive to reducing production costs. 3 / SAG S5 ≥23.5, the thickness of the third lens 130 is too large, which is not conducive to the lightweight and miniaturization of the imaging lens. 3 / SAG S5 When ≤3, the object side of the third lens 130 is too curved, and the lens processing difficulty increases; at the same time, the surface is too curved, which is prone to edge aberration, which is not conducive to improving the image quality of the imaging system.

[0081] The imaging system also satisfies the following condition: -31 mm 2 <f 6 *f 7 <-9mm 2 , where f 6 is the focal length of the sixth lens 160, f 7 is the focal length of the seventh lens 170. Based on the above embodiment, by reasonably limiting the focal lengths of the sixth lens 160 and the seventh lens 170, it is beneficial to further eliminate aberrations and correct the astigmatism phenomenon caused by the refracting of light through the front lens group.

[0082] The imaging system also satisfies the following condition: 13.5<(Nd 5 -Nd 4 )*100<23, where Nd 5 is the d-light refractive index of the fifth lens 150, Nd 4 is the d-light refractive index of the fourth lens 140. Based on the above embodiment, by reasonably limiting the d-light refractive index of the fifth lens 150 and the d-light refractive index of the fourth lens 140, it is beneficial to optimize the aberration and improve the imaging resolution. 5 -Nd 4 )*100≥23 or (Nd5 -Nd 4 ) * 100 ≤ 13.5, it is not conducive to the correction of the aberration of the imaging system, thereby reducing the imaging quality.

[0083] The imaging system further satisfies the following conditional formula: 3.5 < TTL / DOS < 6, where TTL is the distance from the object side of the first lens 110 to the image plane on the optical axis, and DOS is the distance from the object side of the first lens 110 to the stop STO on the optical axis. Based on the above embodiments, by reasonably defining the distance from the object side of the first lens 110 to the image plane on the optical axis and the distance from the object side of the first lens 110 to the stop STO on the optical axis, it is beneficial to make the structure of the imaging system compact and miniaturized. When TTL / DOS ≥ 6, the overall optical length of the imaging system is too long, which is not conducive to the miniaturization of the imaging system. When TTL / DOS ≤ 3.5, it is difficult for large-angle light beams to enter the imaging system, reducing the object space imaging range of the imaging lens and making it difficult to achieve wide-angle.

[0084] To reduce stray light and improve the imaging effect, the imaging system may further include a stop STO. The stop STO may be an aperture stop STO and / or a field stop STO. In the embodiments of the present application, an aperture stop is used. The stop STO may be located between the object plane and the image plane. For example, the stop STO may be located between the object side of the first lens 110 and the object plane, between the image side of the first lens 110 and the object side of the second lens 120, between the image side of the second lens 120 and the object side of the third lens 130, between the image side of the third lens 130 and the object side of the fourth lens 140, between the image side of the fourth lens 140 and the object side of the fifth lens 150, between the image side of the fifth lens 150 and the object side of the sixth lens 160, between the image side of the sixth lens 160 and the object side of the seventh lens 170, or between the image side of the seventh lens 170 and the image plane. To reduce the processing cost, the stop STO may also be provided on any one of the surfaces of the object side of the first lens 110, the object side of the second lens 120, the object side of the third lens 130, the object side of the fourth lens 140, the object side of the fifth lens 150, the object side of the sixth lens 160, the object side of the seventh lens 170, the image side of the first lens 110, the image side of the second lens 120, the image side of the third lens 130, the image side of the fourth lens 140, the image side of the fifth lens 150, the image side of the sixth lens 160, and the image side of the seventh lens 170.

[0085] To filter the non-working band, the imaging system may further include a filter 180 and a protective glass 190. Preferably, the protective glass 190 may be located on the side of the image plane close to the seventh lens 170, and the filter 180 may be located between the seventh lens 170 and the protective glass 190.

[0086] In a second aspect, an embodiment of the present application provides a lens module. The lens module includes a lens barrel, any of the above-mentioned imaging systems, and a photosensitive element. The imaging system is arranged in the lens barrel, and the photosensitive element is arranged on the image side of the imaging system.

[0087] Based on the lens module in the embodiment of the present application, the imaging quality can be improved, and high pixels and a large depth of field can be ensured by reasonably designing the refractive power and surface shape of the first lens 110 to the seventh lens 170. By reasonably limiting the focal length of the fourth lens 140, the focal length of the fifth lens 150 and the focal length of the imaging system, it is helpful to correct the aberration caused by the refracting of the light through the front lens, improve the resolution of the imaging system, and by satisfying the relationship condition, it is helpful to reduce the angle of the light emitted from the imaging system after being refracted by the lens group, and improve the high-quality imaging picture of the imaging system.

[0088] In a third aspect, an embodiment of the present application provides an electronic device, which includes a housing and the above-mentioned lens module, wherein the lens module is disposed in the housing.

[0089] Based on the electronic device in the embodiment of the present application, the imaging quality can be improved, and high pixels and a large depth of field can be ensured by reasonably designing the refractive power and surface shape of the first lens 110 to the seventh lens 170. By reasonably limiting the focal length of the fourth lens 140, the focal length of the fifth lens 150 and the focal length of the imaging system, it is helpful to correct the aberration caused by the refracting of the light through the front lens, improve the resolution of the imaging system, and by satisfying the relationship condition, it is helpful to reduce the angle of the light emitted from the imaging system after being refracted by the lens group, and improve the high-quality imaging picture of the imaging system.

[0090] The imaging system will be described in detail below in combination with specific parameters. Specific embodiment 1

[0092] See the structural diagram of the imaging system of the embodiment of the present application for Figure 1The imaging system includes a first lens 110, a stop STO, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, a seventh lens 170, a filter 180 and a protective glass 190, which are arranged in sequence from the object plane to the image plane along the optical axis. The object side surface S1 of the first lens 110 is a convex surface at the near optical axis, and the image side surface S2 of the first lens 110 is a concave surface at the near optical axis. The object side surface S3 of the second lens 120 is a concave surface at the near optical axis, and the image side surface S4 of the second lens 120 is a plane at the near optical axis. The object side surface S5 of the third lens 130 is a convex surface at the near optical axis, and the image side surface S6 of the third lens 130 is a convex surface at the near optical axis. The object side surface S7 of the fourth lens 140 is a convex surface at the near optical axis, and the image side surface S8 of the fourth lens 140 is a convex surface at the near optical axis. The object-side surface S8 of the fifth lens 150 is concave at the near optical axis, and the image-side surface S9 of the fifth lens 150 is convex at the near optical axis. The object-side surface S10 of the sixth lens 160 is convex at the near optical axis, and the image-side surface S11 of the sixth lens 160 is concave at the near optical axis. The object-side surface S11 of the seventh lens 170 is convex at the near optical axis, and the image-side surface S12 of the seventh lens 170 is concave at the near optical axis.

[0093] In the embodiment of the present application, the reference wavelength of the focal length of each lens is 546.074 nm, the reference wavelength of the refractive index and the Abbe number is 587.56 nm, and the relevant parameters of the imaging system are shown in Table 1. In Table 1, f is the focal length of the imaging system, FNO represents the aperture number, FOV represents the maximum field of view of the imaging system; the units of focal length, radius of curvature and thickness are all millimeters.

[0094] Table 1

[0095]

[0096] The surface of the lens of the imaging system may be aspherical. For these aspherical surfaces, the aspherical equation of the aspherical surface is:

[0097]

[0098] Wherein, Z is the distance from the corresponding point on the aspheric surface to the plane tangent to the vertex of the surface, r is the distance from the corresponding point on the aspheric surface to the optical axis, c represents the curvature of the surface at the vertex, K represents the cone constant, and A4, A6, A8, A10, and A12 represent the aspheric coefficients of the 4th, 6th, 8th, 10th, and 12th order, respectively. In the embodiment of the present application, the cone constant K and aspheric coefficients corresponding to the surface of the aspheric surface are shown in Table 2:

[0099] Table 2

[0100] Surface number 1 2 6 7 K 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A4 -3.517E-05 -4.225E-05 -3.600E-05 -5.773E-05 A6 -1.844E-06 -4.677E-06 -3.258E-08 -4.448E-07 A8 -2.724E-09 4.405E-08 1.451E-09 -1.173E-09 A10 -6.307E-10 -6.604E-09 0.000E+00 0.000E+00 A12 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A14 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A18 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A20 0.000E+00 0.000E+00 0.000E+00 0.000E+00

[0101] Figure 2 a is a longitudinal spherical aberration curve of light at wavelengths of 656.2725nm, 587.5618nm, 546.0740nm, 486.1327nm, and 435.8343nm in the embodiment of the present application, Figure 2 It can be seen from a that the longitudinal spherical aberrations corresponding to the wavelengths of 656.2725nm, 587.5618nm, 546.0740nm, 486.1327nm, and 435.8343nm are all within 0.050 mm, indicating that the imaging quality of the embodiment of the present application is good.

[0102] Figure 2 (b) is the astigmatism diagram of the imaging system in the first embodiment at a wavelength of 546.0740 nm. The horizontal axis along the X-axis direction represents the focus offset, and the vertical axis along the Y-axis direction represents the image height, and the unit is mm. The astigmatism curve represents the meridian imaging surface curvature T and the sagittal imaging surface curvature S, which is represented by Figure 2 (b) It can be seen that the astigmatism of the imaging system is well compensated.

[0103] See also Figure 2 (c) Figure 2 (c) is a distortion curve diagram of the imaging system in the first embodiment at a wavelength of 546.0740 nm. The horizontal axis along the X-axis direction represents the distortion, and the vertical axis along the Y-axis direction represents the image height. Figure 2 (c) It can be seen that at a wavelength of 546.0740 nm, the distortion of the imaging system is well corrected.

[0104] Depend on Figure 2 (a) Figure 2 (b) and Figure 2 (c) It can be seen that the aberration of the imaging system in this embodiment is small Specific embodiment 2

[0106] See the structural diagram of the imaging system of the embodiment of the present application for Figure 3The imaging system includes a first lens 110, a stop STO, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, a seventh lens 170, a filter 180 and a protective glass 190, which are arranged in sequence from the object plane to the image plane along the optical axis. The object side surface S1 of the first lens 110 is a convex surface at the near optical axis, and the image side surface S2 of the first lens 110 is a concave surface at the near optical axis. The object side surface S3 of the second lens 120 is a concave surface at the near optical axis, and the image side surface S4 of the second lens 120 is a convex surface at the near optical axis. The object side surface S5 of the third lens 130 is a convex surface at the near optical axis, and the image side surface S6 of the third lens 130 is a convex surface at the near optical axis. The object side surface S7 of the fourth lens 140 is a convex surface at the near optical axis, and the image side surface S8 of the fourth lens 140 is a convex surface at the near optical axis. The object-side surface S8 of the fifth lens 150 is concave at the near optical axis, and the image-side surface S9 of the fifth lens 150 is convex at the near optical axis. The object-side surface S10 of the sixth lens 160 is convex at the near optical axis, and the image-side surface S11 of the sixth lens 160 is concave at the near optical axis. The object-side surface S11 of the seventh lens 170 is convex at the near optical axis, and the image-side surface S12 of the seventh lens 170 is concave at the near optical axis.

[0107] In the embodiment of the present application, the reference wavelength of the focal length of each lens is 546.074 nm, the reference wavelength of the refractive index and the Abbe number is 587.56 nm, and the relevant parameters of the imaging system are shown in Table 3, where f is the focal length of the imaging system, FNO represents the aperture number, and FOV represents the maximum field of view of the imaging system; the units of the focal length, radius of curvature and thickness are all millimeters.

[0108] Table 3

[0109]

[0110] The surface of the lens of the imaging system may be aspherical. For these aspherical surfaces, the aspherical equation of the aspherical surface is:

[0111]

[0112] Wherein, Z is the distance from the corresponding point on the aspheric surface to the plane tangent to the vertex of the surface, r is the distance from the corresponding point on the aspheric surface to the optical axis, c represents the curvature of the surface at the vertex, K represents the cone constant, and A4, A6, A8, A10, and A12 represent the aspheric coefficients of the 4th, 6th, 8th, 10th, and 12th order, respectively. In the embodiment of the present application, the cone constant K and aspheric coefficients corresponding to the surface of the aspheric surface are shown in Table 4:

[0113] Table 4

[0114] Surface number 1 2 6 7 K 1.684E-01 6.088E-01 2.171E+00 2.949E-02 A4 -1.042E-04 -3.274E-05 -6.439E-05 -6.370E-05 A6 -6.516E-07 -4.904E-06 -3.352E-07 -4.273E-07 A8 -1.702E-08 -9.519E-08 2.055E-08 -1.365E-08 A10 -2.432E-10 -1.020E-09 -8.455E-10 1.807E-10 A12 -4.763E-12 -1.653E-10 3.055E-12 -2.505E-12 A14 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A18 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A20 0.000E+00 0.000E+00 0.000E+00 0.000E+00

[0115] Depend on Figure 4 It can be seen from the aberration diagram in that the longitudinal spherical aberration, field curvature and distortion of the imaging system are all well controlled, so that the imaging system of this embodiment has good imaging quality. Specific embodiment three

[0117] See the structural diagram of the imaging system of the embodiment of the present application for Figure 5 The imaging system includes a first lens 110, a stop STO, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, a seventh lens 170, a filter 180 and a protective glass 190, which are arranged in sequence from the object plane to the image plane along the optical axis. The object side surface S1 of the first lens 110 is a convex surface at the near optical axis, and the image side surface S2 of the first lens 110 is a concave surface at the near optical axis. The object side surface S3 of the second lens 120 is a concave surface at the near optical axis, and the image side surface S4 of the second lens 120 is a convex surface at the near optical axis. The object side surface S5 of the third lens 130 is a convex surface at the near optical axis, and the image side surface S6 of the third lens 130 is a convex surface at the near optical axis. The object side surface S7 of the fourth lens 140 is a convex surface at the near optical axis, and the image side surface S8 of the fourth lens 140 is a convex surface at the near optical axis. The object-side surface S8 of the fifth lens 150 is concave at the near optical axis, and the image-side surface S9 of the fifth lens 150 is concave at the near optical axis. The object-side surface S9 of the sixth lens 160 is convex at the near optical axis, and the image-side surface S10 of the sixth lens 160 is concave at the near optical axis. The object-side surface S11 of the seventh lens 170 is convex at the near optical axis, and the image-side surface S12 of the seventh lens 170 is concave at the near optical axis.

[0118] In the embodiment of the present application, the reference wavelength of the focal length of each lens is 546.074 nm, the reference wavelength of the refractive index and the Abbe number is 587.56 nm, and the relevant parameters of the imaging system are shown in Table 5, where f is the focal length of the imaging system, FNO represents the aperture number, and FOV represents the maximum field of view of the imaging system; the units of the focal length, radius of curvature and thickness are all millimeters.

[0119] Table 5

[0120]

[0121] The surface of the lens of the imaging system may be aspherical. For these aspherical surfaces, the aspherical equation of the aspherical surface is:

[0122]

[0123] Wherein, Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, r is the distance from the corresponding point on the aspherical surface to the optical axis, c represents the curvature of the surface at the vertex, K represents the cone constant, and A4, A6, A8, A10, and A12 represent the aspherical coefficients of the 4th, 6th, 8th, 10th, and 12th orders, respectively. In the embodiment of the present application, the cone constant K and aspherical coefficients corresponding to the surface of the aspherical surface are shown in Table 6:

[0124] Table 6

[0125] Surface number 1 2 12 13 K -3.716E-01 4.905E-02 0.000E+00 0.000E+00 A4 -1.077E-05 -1.824E-04 -4.971E-04 -2.772E-04 A6 -5.598E-07 -7.132E-06 2.187E-07 6.255E-06 A8 -2.246E-09 2.891E-08 1.262E-07 2.460E-07 A10 -2.835E-11 -1.085E-08 -2.348E-09 -2.794E-09 A12 -3.387E-12 0.000E+00 0.000E+00 0.000E+00 A14 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A18 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A20 0.000E+00 0.000E+00 0.000E+00 0.000E+00

[0126] Depend on Figure 6 It can be seen from the aberration diagram in that the longitudinal spherical aberration, field curvature and distortion of the imaging system are all well controlled, so that the imaging system of this embodiment has good imaging quality. Specific embodiment 4

[0128] See the structural diagram of the imaging system of the embodiment of the present application for Figure 7 The imaging system includes a first lens 110, a stop STO, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, a seventh lens 170, a filter 180 and a protective glass 190, which are arranged in sequence from the object plane to the image plane along the optical axis. The object side surface S1 of the first lens 110 is a convex surface at the near optical axis, and the image side surface S2 of the first lens 110 is a concave surface at the near optical axis. The object side surface S3 of the second lens 120 is a concave surface at the near optical axis, and the image side surface S4 of the second lens 120 is a convex surface at the near optical axis. The object side surface S5 of the third lens 130 is a convex surface at the near optical axis, and the image side surface S6 of the third lens 130 is a convex surface at the near optical axis. The object side surface S7 of the fourth lens 140 is a convex surface at the near optical axis, and the image side surface S8 of the fourth lens 140 is a convex surface at the near optical axis. The object-side surface S8 of the fifth lens 150 is concave at the near optical axis, and the image-side surface S9 of the fifth lens 150 is concave at the near optical axis. The object-side surface S10 of the sixth lens 160 is convex at the near optical axis, and the image-side surface S11 of the sixth lens 160 is convex at the near optical axis. The object-side surface S12 of the seventh lens 170 is convex at the near optical axis, and the image-side surface S13 of the seventh lens 170 is concave at the near optical axis.

[0129] In the embodiment of the present application, the reference wavelength of the focal length of each lens is 546.074 nm, the reference wavelength of the refractive index and the Abbe number is 587.56 nm, and the relevant parameters of the imaging system are shown in Table 7. In Table 7, f is the focal length of the imaging system, FNO represents the aperture number, FOV represents the maximum field of view of the imaging system; the units of focal length, radius of curvature and thickness are all millimeters.

[0130] Table 7

[0131]

[0132] The surface of the lens of the imaging system may be aspherical. For these aspherical surfaces, the aspherical equation of the aspherical surface is:

[0133]

[0134] Wherein, Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, r is the distance from the corresponding point on the aspherical surface to the optical axis, c represents the curvature of the surface at the vertex, K represents the cone constant, and A4, A6, A8, A10, and A12 represent the aspherical coefficients of the 4th, 6th, 8th, 10th, and 12th orders, respectively. In the embodiment of the present application, the cone constant K and aspherical coefficients corresponding to the surface of the aspherical surface are shown in Table 8:

[0135] Table 8

[0136] Surface number 1 2 13 14 K -1.962E-01 -4.315E-02 0.000E+00 0.000E+00 A4 -2.534E-05 -1.774E-04 -3.029E-04 -5.753E-04 A6 -5.730E-06 -9.725E-06 2.561E-06 1.381E-05 A8 -2.088E-08 -5.944E-08 -2.124E-07 -3.432E-08 A10 -2.293E-10 -3.096E-09 5.715E-10 -1.026E-09 A12 -5.492E-12 -1.924E-10 0.000E+00 0.000E+00 A14 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A18 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A20 0.000E+00 0.000E+00 0.000E+00 0.000E+00

[0137] Depend on Figure 8 It can be seen from the aberration diagram in that the longitudinal spherical aberration, field curvature and distortion of the imaging system are all well controlled, so that the imaging system of this embodiment has good imaging quality. Specific embodiment five

[0139] See the structural diagram of the imaging system of the embodiment of the present application for Fig. 9 The imaging system includes a first lens 110, a stop STO, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, a seventh lens 170, a filter 180 and a protective glass 190, which are arranged in sequence from the object plane to the image plane along the optical axis. The object side surface S1 of the first lens 110 is a convex surface at the near optical axis, and the image side surface S2 of the first lens 110 is a concave surface at the near optical axis. The object side surface S3 of the second lens 120 is a concave surface at the near optical axis, and the image side surface S4 of the second lens 120 is a convex surface at the near optical axis. The object side surface S5 of the third lens 130 is a convex surface at the near optical axis, and the image side surface S6 of the third lens 130 is a convex surface at the near optical axis. The object side surface S7 of the fourth lens 140 is a convex surface at the near optical axis, and the image side surface S8 of the fourth lens 140 is a convex surface at the near optical axis. The object-side surface S8 of the fifth lens 150 is concave at the near optical axis, and the image-side surface S9 of the fifth lens 150 is concave at the near optical axis. The object-side surface S10 of the sixth lens 160 is convex at the near optical axis, and the image-side surface S11 of the sixth lens 160 is convex at the near optical axis. The object-side surface S12 of the seventh lens 170 is convex at the near optical axis, and the image-side surface S13 of the seventh lens 170 is concave at the near optical axis.

[0140] In the embodiment of the present application, the reference wavelength of the focal length of each lens is 546.074 nm, the reference wavelength of the refractive index and the Abbe number is 587.56 nm, and the relevant parameters of the imaging system are shown in Table 9, where f is the focal length of the imaging system, FNO represents the aperture number, and FOV represents the maximum field of view of the imaging system; the units of the focal length, radius of curvature and thickness are all millimeters.

[0141] Table 9

[0142]

[0143] The surface of the lens of the imaging system may be aspherical. For these aspherical surfaces, the aspherical equation of the aspherical surface is:

[0144]

[0145] Wherein, Z is the distance from the corresponding point on the aspheric surface to the plane tangent to the vertex of the surface, r is the distance from the corresponding point on the aspheric surface to the optical axis, c represents the curvature of the surface at the vertex, K represents the cone constant, and A4, A6, A8, A10, and A12 represent the aspheric coefficients of the 4th, 6th, 8th, 10th, and 12th orders, respectively. In the embodiment of the present application, the cone constant K and aspheric coefficients corresponding to the surface of the aspheric surface are shown in Table 10:

[0146] Table 10

[0147] Surface number 1 2 13 14 K -3.419E-01 3.669E-02 0.000E+00 0.000E+00 A4 -2.700E-05 -2.466E-04 -2.692E-04 1.718E-06 A6 -1.354E-06 -1.057E-05 4.158E-06 1.300E-05 A8 5.399E-09 -1.082E-07 -1.071E-07 -1.959E-08 A10 -3.157E-10 -3.442E-09 2.943E-10 3.548E-09 A12 -7.070E-13 -3.932E-10 0.000E+00 0.000E+00 A14 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A18 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A20 0.000E+00 0.000E+00 0.000E+00 0.000E+00

[0148] Depend on Fig.10 It can be seen from the aberration diagram in that the longitudinal spherical aberration, field curvature and distortion of the imaging system are all well controlled, so that the imaging system of this embodiment has good imaging quality. Specific embodiment six

[0150] See the structural diagram of the imaging system of the embodiment of the present application for Fig.11The imaging system includes a first lens 110, a stop STO, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, a seventh lens 170, a filter 180 and a protective glass 190, which are arranged in sequence from the object plane to the image plane along the optical axis. The object side surface S1 of the first lens 110 is a convex surface at the near optical axis, and the image side surface S2 of the first lens 110 is a concave surface at the near optical axis. The object side surface S3 of the second lens 120 is a concave surface at the near optical axis, and the image side surface S4 of the second lens 120 is a convex surface at the near optical axis. The object side surface S5 of the third lens 130 is a convex surface at the near optical axis, and the image side surface S6 of the third lens 130 is a convex surface at the near optical axis. The object side surface S7 of the fourth lens 140 is a convex surface at the near optical axis, and the image side surface S8 of the fourth lens 140 is a convex surface at the near optical axis. The object-side surface S8 of the fifth lens 150 is concave at the near optical axis, and the image-side surface S9 of the fifth lens 150 is concave at the near optical axis. The object-side surface S10 of the sixth lens 160 is convex at the near optical axis, and the image-side surface S11 of the sixth lens 160 is convex at the near optical axis. The object-side surface S12 of the seventh lens 170 is convex at the near optical axis, and the image-side surface S13 of the seventh lens 170 is concave at the near optical axis.

[0151] In the embodiment of the present application, the reference wavelength of the focal length of each lens is 546.074 nm, the reference wavelength of the refractive index and the Abbe number is 587.56 nm, and the relevant parameters of the imaging system are shown in Table 11. In Table 11, f is the focal length of the imaging system, FNO represents the aperture number, FOV represents the maximum field of view of the imaging system; the units of focal length, radius of curvature and thickness are all millimeters.

[0152] Table 11

[0153]

[0154] The surface of the lens of the imaging system may be aspherical. For these aspherical surfaces, the aspherical equation of the aspherical surface is:

[0155]

[0156] Wherein, Z is the distance from the corresponding point on the aspheric surface to the plane tangent to the vertex of the surface, r is the distance from the corresponding point on the aspheric surface to the optical axis, c represents the curvature of the surface at the vertex, K represents the cone constant, and A4, A6, A8, A10, and A12 represent the aspheric coefficients of the 4th, 6th, 8th, 10th, and 12th orders, respectively. In the embodiment of the present application, the cone constant K and aspheric coefficients corresponding to the surface of the aspheric surface are shown in Table 10:

[0157] Table 12

[0158] Surface number 1 2 13 14 K -3.759E-01 2.469E-02 0.000E+00 0.000E+00 A4 -1.553E-05 -1.167E-04 -3.118E-04 -8.827E-05 A6 -3.149E-06 -9.736E-06 5.337E-06 1.141E-05 A8 -1.847E-09 -1.152E-07 0.000E+00 2.256E-09 A10 -1.901E-10 -2.168E-09 3.385E-11 2.043E-09 A12 -3.593E-12 -3.620E-10 0.000E+00 0.000E+00 A14 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A18 0.000E+00 0.000E+00 0.000E+00 0.000E+00 A20 0.000E+00 0.000E+00 0.000E+00 0.000E+00

[0159] Depend on Fig.12 It can be seen from the aberration diagram in that the longitudinal spherical aberration, field curvature and distortion of the imaging system are all well controlled, so that the imaging system of this embodiment has good imaging quality.

[0160] The data of the above six groups of embodiments are as shown in Table 13 below:

[0161]

[0162] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of this application, it should be understood that if the terms "upper", "lower", "left", "right", etc. indicate an orientation or position relationship based on the orientation or position relationship shown in the drawings, it is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as a limitation on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0163] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An imaging system, characterized in that: The imaging system includes, in sequence from the object plane to the image plane along the optical axis: A first lens, wherein the first lens has negative refractive power, and an object side surface of the first lens is convex at a near optical axis; A second lens, wherein the second lens has negative refractive power, and an object side surface of the second lens is concave at a near optical axis; A third lens, the third lens has positive refractive power, and the object side surface of the third lens is convex at the near optical axis; a fourth lens having positive refractive power, an object-side surface of the fourth lens being convex at the near optical axis, and an image-side surface of the fourth lens being convex at the near optical axis; a fifth lens having negative refractive power, wherein the object side surface of the fifth lens is concave at a near optical axis; a sixth lens having positive refractive power, wherein the object side surface of the sixth lens is a convex surface near the optical axis; a seventh lens having negative refractive power, and an object-side surface of the seventh lens being convex near the optical axis; The imaging system further includes an aperture; Wherein, the imaging system satisfies the following conditional formula: -19.5mm <f4*f5 / f<-4mm、8<SD S3 / CASE S3 <25; Wherein, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f is the focal length of the imaging system, SD S3 is the maximum effective aperture of the object side of the second lens, SAG S3 is the sagittal height of the object side of the second lens at the maximum effective radius.

2. An imaging system as claimed in claim 1, characterized in that: The imaging system also satisfies the following conditional formula: -8 <f1 / f<-4; Wherein, f1 is the focal length of the first lens.

3. An imaging system as claimed in claim 1, characterized in that: The imaging system also satisfies the following conditional formula: -5 <f2 / f<-1; Wherein, f2 is the focal length of the second lens.

4. An imaging system as claimed in claim 1, characterized in that: The imaging system also satisfies the following conditional formula: 3<CT3 / SAG S5 <23.5; Wherein, CT3 is the thickness of the third lens on the optical axis, SAG S5 is the sagittal height of the object side of the third lens at the maximum effective radius.

5. An imaging system as claimed in claim 1, characterized in that: The imaging system also satisfies the following conditional formula: -31mm 2 <f6*f7<-9mm 2 ; Wherein, f6 is the focal length of the sixth lens, and f7 is the focal length of the seventh lens.

6. An imaging system as claimed in claim 1, characterized in that: The imaging system also satisfies the following conditional formula: 13.5<(Nd5-Nd4)*100<23; Wherein, Nd5 is the d-light refractive index of the fifth lens, and Nd4 is the d-light refractive index of the fourth lens.

7. An imaging system as claimed in claim 1, characterized in that: The imaging system also satisfies the following conditional formula: 3.5 <TTL / DOS<6; Wherein, TTL is the distance from the object side surface of the first lens to the image plane on the optical axis, and DOS is the distance from the object side surface of the first lens to the aperture on the optical axis.

8. A lens module, characterized in that: include: Lens tube; The imaging system according to any one of claims 1 to 7, wherein the imaging system is arranged in the lens barrel; A photosensitive element is arranged on the image side of the imaging system.

9. An electronic device, characterized in that: include: case; and The lens module described in claim 8 is arranged in the shell.

Images