Optical System, Camera Module and Electronic Device

Abstract

The present invention relates to an optical system, a camera module and an electronic device. The optical system sequentially includes, from the object side to the image side: a positive first lens, the object side surface and the image side surface of which are convex at the paraxial region; a negative second lens, the object side surface of which is convex at the paraxial region and the image side surface of which is concave at the paraxial region; a third lens; a fourth lens; a fifth lens, the object side surface of the fifth lens being concave at the paraxial region and the image side surface of which being convex at the paraxial region; a sixth lens; a seventh lens; the system satisfies the relationship: 20° < HFOV < 26°; 0.9 < TTL / f < 1.2; HFOV is half of the maximum field of view angle of the optical system, TTL is the distance on the optical axis from the object side surface of the first lens to the imaging surface of the optical system, and f is the effective focal length of the optical system. The above optical system has a small field of view and telephoto performance, and has a shorter axial length. Under the condition of realizing telephoto, it is also beneficial to further balance aberrations such as chromatic aberration and spherical aberration during telephoto.

Description

Technical Field

[0001] The present invention relates to the technical field of photographic imaging, and particularly to an optical system, a camera module, and an electronic device. Background Art

[0002] With the trend that the requirements for portability of electronic products are gradually increasing, the internal components of electronic products are required to have thinner and lighter characteristics. Generally, in the process of ultra-thin design of electronic products such as smart phones and tablet computers, it is often difficult to reduce the thickness due to the axial dimension of the camera module. Summary of the Invention

[0003] Based on this, it is necessary to provide an optical system, a camera module, and an electronic device for the problem of how to reduce the axial dimension of the module.

[0004] An optical system, sequentially including from the object side to the image side:

[0005] A first lens with positive refractive power, the object side surface of the first lens is convex at the paraxial region, and the image side surface is convex at the paraxial region;

[0006] A second lens with negative refractive power, the object side surface of the second lens is convex at the paraxial region, and the image side surface is concave at the paraxial region;

[0007] A third lens with refractive power;

[0008] A fourth lens with refractive power;

[0009] A fifth lens with refractive power, the object side surface of the fifth lens is concave at the paraxial region, and the image side surface is convex at the paraxial region;

[0010] A sixth lens with refractive power;

[0011] A seventh lens with refractive power;

[0012] And the optical system satisfies the relationship:

[0013] 20° < HFOV < 26°;

[0014] 0.9 < TTL / f < 1.2;

[0015] HFOV is half of the maximum field of view angle of the optical system, TTL is the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis, and f is the effective focal length of the optical system.

[0016] The above optical system has a seven-lens structure. The first lens has a positive refractive power, and both its object side and image side are convex at the paraxial region, thereby providing the optical system with a relatively strong ability to converge light rays, which helps to shorten the total axial length of the system. The second lens with a negative refractive power can be used to well correct the axial chromatic aberration and spherical aberration brought by the first lens. In particular, since the object side of the second lens is convex at the paraxial region and the image side is concave at the paraxial region, it helps to prevent overcorrection of the spherical aberration and axial chromatic aberration of the first lens.

[0017] In addition, when the optical system satisfies the above relationship of HFOV, it can have small field of view and telephoto performance. When further satisfying the above relationship of TTL / f, the optical system will have a shorter axial length under the condition of HFOV < 26°, so that it can be better applied to electronic products with ultra-thin design and requiring telephoto performance. At the same time, under the condition of achieving telephoto, there is a good configuration between the overall optical length and the effective focal length of the optical system that satisfies the above relationship. When TTL / f is higher than the lower limit, it is beneficial for the optical system to further balance aberrations such as chromatic aberration and spherical aberration during telephoto, thereby improving the imaging quality during telephoto; when TTL / f is lower than the upper limit, it can prevent the axial length of the system from being too long. Therefore, by satisfying the above relationship range of TTL / f, the system can be miniaturized while balancing system aberrations.

[0018] In one embodiment, the optical system satisfies the relationship:

[0019] 0.6 < Y11 / Y72 < 1;

[0020] Y11 is the maximum effective aperture of the object side of the first lens, and Y72 is the maximum effective aperture of the image side of the seventh lens. When the above relationship is satisfied, the aperture ratio between the lens surfaces at the most object side and the most image side of the system can be reasonably controlled, thereby suppressing the overall radial size of the optical system, and further reducing the volume of the optical system. When this relationship is lower than the lower limit, the first surface of the lens group is too small compared to the last surface, resulting in insufficient light input to the system and poor imaging quality; when this relationship is higher than the upper limit, it will cause the field of view angle of the system to be too large, which is not conducive to achieving the telephoto effect.

[0021] In one embodiment, the optical system satisfies the relationship:

[0022] (n1 + n2) / f < 0.5mm -1 ;

[0023] Let \(n_1\) be the refractive index of the first lens and \(n_2\) be the refractive index of the second lens. When the above relationships are satisfied, the ratio between the combined refractive power of the first lens and the second lens and the effective refractive power of the overall system can be reasonably allocated, which is beneficial to enhancing the light-gathering ability of the system and at the same time conducive to reducing the overall size of the system.

[0024] In one embodiment, the optical system satisfies the relationship:

[0025] 1.0 < TTL / (ImgH * 2) < 1.5;

[0026] ImgH is half of the image height corresponding to the maximum field of view angle of the optical system. When the above relationship is satisfied, the axial dimension of the optical system and the imaging surface dimension of the system will be reasonably configured, which is beneficial to shortening the axial dimension of the optical system, so that the optical system with telephoto performance can further achieve miniaturized design.

[0027] In one embodiment, the optical system satisfies the relationship:

[0028] 0.8 < DL / TTL < 1;

[0029] DL is the distance on the optical axis from the object side surface of the first lens to the image side surface of the seventh lens. When the above relationship is satisfied, the structure in the optical system can be reasonably arranged. On the basis of achieving miniaturization, it can also reduce the occupied space of the lens group, make the structure of the optical system tend to be compact, and is beneficial to the layout of the module structure end.

[0030] In one embodiment, the optical system satisfies the relationship:

[0031] (|T34| + |T45|) / CT4 > 1;

[0032] T34 is the distance on the optical axis from the image side of the third lens to the object side of the fourth lens, T45 is the distance on the optical axis from the image side of the fourth lens to the object side of the fifth lens, and CT4 is the thickness of the fourth lens on the optical axis. The optical system has a seven-lens structure. The third lens, the fourth lens, and the fifth lens are optical elements located in the middle of the system. When the light rays of the marginal field propagate between these three lenses, they generally go from almost passing through most of the effective light-transmitting area of the third lens to only passing through a part of the area of the fifth lens, that is, the light rays of the off-axis image point will be deflected and turned as a whole towards the edge of the fifth lens. When the above relationships are satisfied, the distances between the third lens, the fourth lens, and the fifth lens can be reasonably increased, thereby slowing down the change in the direction of the light rays when they propagate between the third lens and the fifth lens, suppressing the deflection direction of the marginal light rays of each field in the optical system, and further helping to reduce the generation of astigmatism.

[0033] In one embodiment, the optical system satisfies the relationship:

[0034] 0.4 < |f1 / f2| < 1;

[0035] f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens. When the above relationship is satisfied, by reasonably configuring the sizes and refractive powers of the first lens and the second lens, the large spherical aberration generated by the first lens can be balanced, the resolution of the overall optical lens can be improved, the refractive power configuration at the rear end of the system can be controlled, the correction of the peripheral aberration of the system can be strengthened, and at the same time, it is beneficial to size compression and helps to form a small-sized optical lens.

[0036] In one embodiment, the optical system satisfies the relationship:

[0037] |V2 - V1| > 30;

[0038] V1 is the Abbe number of the first lens, and V2 is the Abbe number of the second lens. When the above relationship is satisfied, it is beneficial to correct the chromatic aberration of the system to improve the imaging quality.

[0039] In one embodiment, the optical system satisfies the relationship:

[0040] (|f2| + |f3|) / |R71| < 20;

[0041] Let \(f_2\) be the effective focal length of the second lens, \(f_3\) be the effective focal length of the third lens, and \(R_{71}\) be the curvature radius of the object side surface of the seventh lens at the optical axis. When the above relationships are satisfied, the refractive power between the second lens and the third lens will be reasonably distributed, which helps to suppress the combined spherical aberration, chromatic aberration, and distortion of the first three lenses of the system, and reduces the design difficulty of the fourth lens to the seventh lens. At the same time, through reasonable configuration with the refractive power of the second lens and the third lens, the curvature distribution of the object side surface of the seventh lens is appropriate, which can avoid excessive bending of the surface shape, thus contributing to the forming and manufacturing of the lens.

[0042] In one embodiment, the optical system satisfies the relationship:

[0043] (f1 + |f2| + |f3|) / f < 10;

[0044] Let \(f_1\) be the effective focal length of the first lens, \(f_2\) be the effective focal length of the second lens, and \(f_3\) be the effective focal length of the third lens. When the above relationships are satisfied, a proper ratio can be obtained between the effective focal lengths of the first lens, the second lens, and the third lens and the effective focal length of the system, which can prevent the refractive power of the first three lenses of the system from being too strong, avoid large spherical aberration in the front lens group, and thus improve the overall resolution of the optical system; at the same time, when the above relationships are satisfied, it is also beneficial to compress the sizes of the first three lenses of the system, which helps in the small-size design of the system.

[0045] In one embodiment, the optical system satisfies the relationship:

[0046] 2 < T23 / T12 < 3.2;

[0047] Let \(T_{12}\) be the distance on the optical axis from the image side surface of the first lens to the object side surface of the second lens, and \(T_{23}\) be the distance on the optical axis from the image side surface of the second lens to the object side surface of the third lens. When the above relationships are satisfied, the spacing distances between the first lens, the second lens, and the third lens can be reasonably controlled, making the spatial arrangement between the lenses more uniform, and thus reducing the assembly difficulty.

[0048] An imaging module includes an image sensor and the optical system according to any one of the above. The image sensor is disposed on the image side of the optical system. By adopting the optical system, the imaging module not only has telephoto performance but also can have a smaller axial size and good imaging quality.

[0049] An electronic device includes the above imaging module. By adopting the imaging module, it can effectively avoid restricting the ultra-thin design of the electronic device. Description of the Drawings

[0050] Figure 1Schematic diagram of the optical system provided by the first embodiment of the present application;

[0051] Figure 2 It includes the longitudinal spherical aberration diagram, astigmatism diagram and distortion diagram of the optical system in the first embodiment;

[0052] Figure 3 Schematic diagram of the optical system provided by the second embodiment of the present application;

[0053] Figure 4 It includes the longitudinal spherical aberration diagram, astigmatism diagram and distortion diagram of the optical system in the second embodiment;

[0054] Figure 5 Schematic diagram of the optical system provided by the third embodiment of the present application;

[0055] Figure 6 It includes the longitudinal spherical aberration diagram, astigmatism diagram and distortion diagram of the optical system in the third embodiment;

[0056] Figure 7 Schematic diagram of the optical system provided by the fourth embodiment of the present application;

[0057] Figure 8 It includes the longitudinal spherical aberration diagram, astigmatism diagram and distortion diagram of the optical system in the fourth embodiment;

[0058] Figure 9 Schematic diagram of the optical system provided by the fifth embodiment of the present application;

[0059] Figure 10 It includes the longitudinal spherical aberration diagram, astigmatism diagram and distortion diagram of the optical system in the fifth embodiment;

[0060] Figure 11 Schematic diagram of the camera module provided by an embodiment of the present application;

[0061] Figure 12 Schematic diagram of the electronic device provided by an embodiment of the present application. Detailed implementation manners

[0062] To make the above objects, features and advantages of the present invention more obvious and understandable, the following will describe the detailed implementation manners of the present invention in conjunction with the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0063] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention 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, it should not be construed as a limitation to the present invention.

[0064] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0065] In the present invention, unless otherwise clearly specified and defined, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0067] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation.

[0068] Reference Figure 1 , in the embodiments of the present application, the optical system 10 sequentially 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 and a seventh lens L7 from the object side to the image side. The first lens L1 has a positive refractive power, and the second lens L2 has a negative refractive power. Each lens in the optical system 10 is coaxially arranged, that is, the optical axes of each lens are located on the same straight line, and this straight line can be called the optical axis of the optical system 10.

[0069] The first lens L1 includes an object side surface S1 and an image side surface S2, the second lens L2 includes an object side surface S3 and an image side surface S4, the third lens L3 includes an object side surface S5 and an image side surface S6, the fourth lens L4 includes an object side surface S7 and an image side surface S8, the fifth lens L5 includes an object side surface S9 and an image side surface S10, the sixth lens L6 includes an object side surface S11 and an image side surface S12, and the seventh lens L7 includes an object side surface S13 and an image side surface S14. In addition, the optical system 10 further has an imaging surface S15, and the imaging surface S15 is located on the image side of the seventh lens L7. Generally, the imaging surface S15 of the optical system 10 coincides with the photosensitive surface of the image sensor. For the convenience of understanding, the imaging surface S15 can be regarded as the photosensitive surface of the image sensor.

[0070] The object side surface S1 of the first lens L1 is convex at the paraxial region, and the image side surface S2 is convex at the paraxial region; the object side surface S3 of the second lens L2 is convex at the paraxial region, and the image side surface S4 is concave at the paraxial region; the object side surface S9 of the fifth lens L5 is concave at the paraxial region, and the image side surface S10 is convex at the paraxial region.

[0071] The optical system of the present application has a seven-piece structure. The first lens L1 has a positive refractive power, and its object side surface S1 and image side surface S2 are both convex at the paraxial region, so as to provide the optical system 10 with a relatively strong ability to converge light rays, which can help shorten the total length of the system in the axial direction. The second lens L2 with a negative refractive power can be used to well correct the axial chromatic aberration and spherical aberration brought by the first lens L1. In particular, since the object side surface S3 of the second lens L2 is convex at the paraxial region and the image side surface S4 is concave at the paraxial region, it can help prevent overcorrection of the spherical aberration and axial chromatic aberration of the first lens L1.

[0072] In some embodiments, at least one surface of each object side and image side of the first lens L1 to the seventh lens L7 is an aspherical surface. For example, the object sides and image sides of the first lens L1 to the seventh lens L7 can both be designed as aspherical surfaces. The setting of the aspherical surface type can further help the optical system 10 eliminate aberrations and solve the problem of visual field distortion. At the same time, it is also beneficial to the miniaturization design of the optical system 10, enabling the optical system 10 to have excellent optical effects while maintaining the miniaturization design. Of course, in some other embodiments, the object side of any one of the first lens L1 to the seventh lens L7 can be a spherical surface or an aspherical surface; the image side of any one of the first lens L1 to the seventh lens L7 can be a spherical surface or an aspherical surface. By the cooperation of the spherical surface and the aspherical surface, the aberration problem can also be effectively eliminated, enabling the optical system 10 to have excellent imaging effects and at the same time improving the flexibility of lens design and assembly. In particular, when the seventh lens L7 is an aspherical lens, it is beneficial to finally correct the aberrations generated by the front lenses, thereby helping to improve the imaging quality. It should be noted that the shapes of the spherical surface or the aspherical surface are not limited to the spherical surface or the aspherical surface shapes shown in the drawings. The drawings are only for illustrative reference and are not drawn strictly to scale.

[0073] The aspherical surface type calculation can refer to the aspherical formula:

[0074]

[0075] where Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the surface vertex, r is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the aspherical surface vertex, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th high-order term in the aspherical surface type formula.

[0076] On the other hand, in some embodiments, when the object side or the image side of a certain lens is an aspherical surface, this surface can be a structure with an overall convex surface or an overall concave surface. Alternatively, this surface can also be designed into a structure with an inflection point. In this case, the surface profile from the center to the edge will change. For example, this surface is convex at the center and concave at the edge. It should be noted that when the embodiment of the present application describes that one side of the lens is convex at the optical axis (the central region of this side), it can be understood that the region near the optical axis of this side of the lens is convex. Therefore, it can also be considered that this side is convex at the paraxial region. When it is described that one side of the lens is concave at the circumference, it can be understood that the region of this side near the maximum effective aperture is concave. For example, when this side is convex at the paraxial region and also convex at the circumference, the shape of this side from the center (optical axis) to the edge direction can be a purely convex surface; or it can first transition from the convex surface shape at the center to a concave surface shape, and then become convex when approaching the maximum effective aperture. The examples here are only for illustrating the relationship between the optical axis and the circumference, and the various shape structures (concave-convex relationship) of the side are not fully reflected. However, other situations can be deduced based on the above examples and should also be regarded as the content recorded in the present application.

[0077] In some embodiments, the material of each lens in the optical system 10 is plastic. Of course, the material of each lens in some embodiments can also be glass. Lenses made of plastic can reduce the weight of the optical system 10 and lower the production cost, while lenses made of glass can withstand higher temperatures and have excellent optical effects. In some other embodiments, the material of the first lens L1 is glass, while the materials of the second lens L2 to the seventh lens L7 are all plastic. At this time, since the material of the lenses located on the object side in the optical system 10 is glass, these glass lenses located on the object side have a good tolerance effect on extreme environments and are not easily affected by the object-side environment and age. Therefore, when the optical system 10 is in extreme environments such as exposure to the sun and high temperatures, this structure can better balance the optical performance and cost of the system. Of course, the material configuration relationship of the lenses in the optical system 10 is not limited to the above embodiments. The material of any lens can be plastic or glass, and the specific design can be determined according to actual needs.

[0078] In some embodiments, the optical system 10 includes an infrared cut-off filter 110. The infrared cut-off filter 110 is disposed on the image side of the seventh lens L7 and is fixedly arranged relative to each lens in the optical system 10. The infrared cut-off filter 110 is used to filter out infrared light to prevent the infrared light from reaching the imaging surface S15 of the system, thereby preventing the infrared light from interfering with normal imaging. The infrared cut-off filter 110 can be assembled together with each lens to be a part of the optical system 10. In some other embodiments, the infrared cut-off filter 110 does not belong to the components of the optical system 10. At this time, the infrared cut-off filter 110 can be installed between the optical system 10 and the image sensor when the optical system 10 and the image sensor are assembled into a camera module. In some embodiments, the infrared cut-off filter 110 can also be disposed on the object side of the first lens L1. Additionally, in some embodiments, the function of filtering out infrared light can also be achieved by providing a filter coating on at least one of the first lens L1 to the seventh lens L7.

[0079] In some embodiments, the optical system 10 further includes an optical path turning element P1 disposed on the object side of the first lens L1. The optical path turning element P1 is used to reflect the incident light to the first lens L1. The optical path turning element P1 can be a triangular prism or other elements that can turn the incident optical path of the optical system 10. By providing the optical path turning element P1, when the optical system 10 is applied to an electronic device, a periscope optical imaging system can be formed, thereby effectively reducing the size of the system in the incident light direction, which is beneficial to the ultra-thin design of the device.

[0080] In the embodiments of the present application, the optical system 10 satisfies the relationship:

[0081] 20° < HFOV < 26°;

[0082] 0.9 < TTL / f < 1.2;

[0083] HFOV is half of the maximum field of view angle of the optical system 10, TTL is the distance from the object side surface S1 of the first lens L1 to the imaging surface S15 of the optical system 10 on the optical axis, and f is the effective focal length of the optical system 10. The HFOV of some optical systems 10 with small field of view and telephoto performance can be 22.3°, 22.5°, 22.7°, 23°, 23.5°, 24°, 24.5°, 24.7° or 25°. The TTL / f in some embodiments can be 0.95, 0.96, 0.98, 1, 1.03, 1.05, 1.07 or 1.1. When the optical system 10 satisfies the above relationship of HFOV, it can have small field of view and telephoto performance. And when further satisfying the above relationship of TTL / f, the optical system 10 will have a shorter axial length under the condition of HFOV < 26°, so that it can be better applied to electronic products with ultra-thin design and requiring telephoto performance. At the same time, under the condition of realizing telephoto, there is a good configuration between the overall optical length and the effective focal length of the optical system 10 that satisfies the above relationship. When TTL / f is higher than the lower limit, it is beneficial for the optical system 10 to further balance aberrations such as chromatic aberration and spherical aberration during telephoto, thereby improving the imaging quality during telephoto. And when TTL / f is lower than the upper limit, the axial length of the system can be prevented from being too long. Therefore, by satisfying the above relationship range of TTL / f, the miniaturized design of the system can be maintained while balancing the system aberrations.

[0084] In addition, in some embodiments, the optical system 10 further satisfies at least one of the following relationships, and corresponding effects can be brought when any relational expression is satisfied:

[0085] 0.6 < Y11 / Y72 < 1; Y11 is the maximum effective aperture of the object side surface S1 of the first lens L1, and Y72 is the maximum effective aperture of the image side surface S14 of the seventh lens L7. The Y11 / Y72 in some embodiments can be 0.63, 0.65, 0.7, 0.75, 0.8, 0.82 or 0.85. When the above relationship is satisfied, the aperture ratio between the lens surfaces at the outermost object side and the outermost image side of the system can be reasonably controlled, so as to suppress the overall radial size of the optical system 10, and further reduce the volume of the optical system 10. When this relationship is lower than the lower limit, the first surface of the lens group (the object side surface S1 of the first lens L1) is too small compared with the last surface (the image side surface S14 of the seventh lens L7), resulting in insufficient light input of the system and poor imaging quality; and when this relationship is higher than the upper limit, it will cause the field of view angle of the system to be too large, which is not conducive to achieving the telephoto effect.

[0086] (n1 + n2) / f < 0.5mm -1; n1 is the refractive index of the first lens L1, and n2 is the refractive index of the second lens L2. In some embodiments, (n1 + n2) / f can be 0.41, 0.42, 0.43, 0.44, 0.45, or 0.46, with the numerical unit being mm -1 . When the above relationship is satisfied, the ratio between the combined refractive power of the first lens L1 and the second lens L2 and the effective refractive power of the overall system can be reasonably allocated, which is beneficial to enhancing the light-gathering ability of the system and at the same time conducive to reducing the overall size of the system.

[0087] 1.0 < TTL / (ImgH * 2) < 1.5; ImgH is half of the image height corresponding to the maximum field of view angle of the optical system 10. In some embodiments, TTL / (ImgH * 2) can be 1.1, 1.12, 1.15, 1.2, 1.25, 1.3, or 1.32. After assembling the image sensor, ImgH can also be understood as the distance from the center of the effective imaging area of the image sensor to the diagonal edge. When the above relationship is satisfied, the axial dimension of the optical system 10 and the dimension of the imaging surface S15 of the system will be reasonably configured, which is beneficial to shortening the axial dimension of the optical system 10, thereby further realizing the miniaturized design of the telephoto optical system 10.

[0088] 0.8 < DL / TTL < 1; DL is the distance on the optical axis from the object side surface S1 of the first lens L1 to the image side surface S14 of the seventh lens L7. In some embodiments, DL / TTL can be 0.82, 0.83, 0.85, 0.87, 0.88, or 0.89. When the above relationship is satisfied, the structure in the optical system 10 can be reasonably arranged. On the basis of realizing miniaturization, it can also reduce the occupied space of the lens group, make the structure of the optical system 10 tend to be compact, and is beneficial to the layout of the module structure end.

[0089] (|T34| + |T45|) / CT4 > 1; T34 is the distance on the optical axis from the image side S6 of the third lens L3 to the object side S7 of the fourth lens L4, T45 is the distance on the optical axis from the image side S8 of the fourth lens L4 to the object side S9 of the fifth lens L5, and CT4 is the thickness of the fourth lens L4 on the optical axis. In some embodiments, (|T34| + |T45|) / CT4 can be 2, 2.1, 2.2, 2.3, 2.5, 2.6, 2.7, or 2.8. The optical system 10 has a seven-lens structure. The third lens L3, the fourth lens L4, and the fifth lens L5 are optical elements provided in the middle of the system. When the light rays in the marginal field of view propagate between these three lenses, generally, they will go from almost passing through most of the effective light-passing regions of the third lens L3 to only passing through partial regions of the fifth lens L5, that is, the light rays of the off-axis image points will undergo an overall offset and refraction toward the edge of the fifth lens L5. When the above relationship is satisfied, the distance between the third lens L3, the fourth lens L4, and the fifth lens L5 can be reasonably increased, thereby slowing down the change in the direction of the light rays when propagating between the third lens L3 and the fifth lens L5, suppressing the deflection direction of the marginal light rays in each field of view in the optical system, and further helping to reduce the generation of astigmatism.

[0090] 0.4 < |f1 / f2| < 1; f1 is the effective focal length of the first lens L1, and f2 is the effective focal length of the second lens L2. In some embodiments, |f1 / f2| can be 0.42, 0.45, 0.48, 0.5, 0.6, 0.65, 0.7, 0.75, 0.77, or 0.79. When the above relationship is satisfied, the sizes and refractive powers of the first lens L1 and the second lens L2 are reasonably configured, which can balance the large spherical aberration generated by the first lens L1, improve the overall resolution of the system, control the refractive power configuration at the rear end of the system, strengthen the correction of the peripheral aberrations of the system, and at the same time, facilitate size compression and help to form a small-sized optical lens.

[0091] |V2 - V1| > 30; V1 is the Abbe number of the first lens L1, and V2 is the Abbe number of the second lens L2. In some embodiments, |V2 - V1| can be 35.7, 35.8, 36, 36.2, 36.4, or 36.5. When the above relationship is satisfied, it is beneficial to correct the chromatic aberration of the system to improve the imaging quality.

[0092] (|f2| + |f3|) / |R71| < 20; where f2 is the effective focal length of the second lens L2, f3 is the effective focal length of the third lens L3, and R71 is the radius of curvature of the object side surface S13 of the seventh lens L7 at the optical axis. In some embodiments, (|f2| + |f3|) / |R71| can be 0.5, 0.7, 1, 2, 5, 10, 12, 14, 16, 17, 17.2, or 17.5. When the above relationship is satisfied, the refractive power between the second lens L2 and the third lens L3 will be reasonably distributed, which helps to suppress the combined spherical aberration, chromatic aberration, and distortion of the first three lenses of the system, and reduces the design difficulty of the fourth lens L4 to the seventh lens L7. At the same time, through reasonable configuration with the refractive powers of the second lens L2 and the third lens L3, the curvature distribution of the object side surface S13 of the seventh lens L7 is appropriate, which can avoid excessive bending of the surface shape, thus contributing to the forming and manufacturing of the lens.

[0093] (f1 + |f2| + |f3|) / f < 10; where f1 is the effective focal length of the first lens L1, f2 is the effective focal length of the second lens L2, and f3 is the effective focal length of the third lens L3. In some embodiments, (f1 + |f2| + |f3|) / f can be 3, 3.1, 3.2, 3.5, 4, 4.5, 5, 8, 9, 9.3, or 9.5. When the above relationship is satisfied, a suitable ratio can be obtained between the effective focal lengths of the first lens L1, the second lens L2, and the third lens L3 and the effective focal length of the system, which can prevent the refractive power of the first three lenses of the system from being too strong, avoid large spherical aberration in the front lens group, and thus improve the overall resolution of the optical system 10; at the same time, when the above relationship is satisfied, it is also beneficial to compress the size of the first three lenses of the system, which helps with the small-size design of the system.

[0094] 2 < T23 / T12 < 3.2; where T12 is the distance on the optical axis from the image side surface S2 of the first lens L1 to the object side surface S3 of the second lens L2, and T23 is the distance on the optical axis from the image side surface S4 of the second lens L2 to the object side surface S5 of the third lens L3. In some embodiments, T23 / T12 can be 2.1, 2.2, 2.3, 2.4, 2.6, 2.8, 2.9, 3, or 3.1. When the above relationship is satisfied, the spacing distance between the first lens L1, the second lens L2, and the third lens L3 can be reasonably controlled, making the spatial arrangement between the lenses more uniform, and thus reducing the assembly difficulty.

[0095] It should be noted that the ranges of the various relational expressions satisfied by the above optical system 10 and the corresponding effects are for the aforementioned seven-piece lens structure.

[0096] Next, the optical system 10 of the present application will be described with more specific and detailed embodiments:

[0097] First Embodiment

[0098] Reference Figure 1 and Figure 2 In the first embodiment, the optical system 10 includes, in order from the object side to the image side, an aperture stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with negative refractive power, a fourth lens L4 with negative refractive power, a fifth lens L5 with positive refractive power, a sixth lens L6 with negative refractive power, and a seventh lens L7 with positive refractive power. Figure 2 Include the longitudinal spherical aberration diagram, astigmatism diagram, and distortion diagram of the optical system 10 in the first embodiment, where the reference wavelengths of the astigmatism diagram and the distortion diagram are 555 nm.

[0099] The object side surface S1 of the first lens L1 is convex at the paraxial region, and the image side surface S2 is convex at the paraxial region; the object side surface S1 is convex at the circumference, and the image side surface S2 is convex at the circumference.

[0100] The object side surface S3 of the second lens L2 is convex at the paraxial region, and the image side surface S4 is concave at the paraxial region; the object side surface S3 is convex at the circumference, and the image side surface S4 is concave at the circumference.

[0101] The object side surface S5 of the third lens L3 is convex at the paraxial region, and the image side surface S6 is concave at the paraxial region; the object side surface S5 is convex at the circumference, and the image side surface S6 is concave at the circumference.

[0102] The object side surface S7 of the fourth lens L4 is concave at the paraxial region, and the image side surface S8 is convex at the paraxial region; the object side surface S7 is concave at the circumference, and the image side surface S8 is convex at the circumference.

[0103] The object side surface S9 of the fifth lens L5 is concave at the paraxial region, and the image side surface S10 is convex at the paraxial region; the object side surface S9 is concave at the circumference, and the image side surface S10 is convex at the circumference.

[0104] The object side surface S11 of the sixth lens L6 is concave at the paraxial region, and the image side surface S12 is convex at the paraxial region; the object side surface S11 is concave at the circumference, and the image side surface S12 is convex at the circumference.

[0105] The object side surface S13 of the seventh lens L7 is concave at the paraxial region, and the image side surface S14 is convex at the paraxial region; the object side surface S13 is concave at the circumference, and the image side surface S14 is convex at the circumference.

[0106] The object side surfaces and image side surfaces of each of the first lens L1 to the seventh lens L7 are aspherical surfaces. By matching the aspherical surface profiles of the lenses in the optical system 10, the problem of visual field distortion of the optical system 10 can be effectively solved, and excellent optical effects can also be achieved with smaller and thinner lenses. Furthermore, the optical system 10 has a smaller volume, which is conducive to the miniaturization design of the optical system 10.

[0107] In addition, the material of each lens in the optical system 10 is plastic. The use of plastic lenses can reduce the manufacturing cost of the optical system 10.

[0108] The parameters of each lens of the optical system 10 are given in Table 1 and Table 2 below. Table 2 shows the aspheric coefficients of the corresponding surfaces of each lens in Table 1, where k is the conic coefficient and Ai is the coefficient corresponding to the i-th high-order term in the aspheric surface formula. The components from the object surface to the image surface (imaging surface S15, which can also be understood as the photosensitive surface of the image sensor during later assembly) are arranged in the order of the components in Table 1 from top to bottom. The surfaces corresponding to surface numbers 1 and 2 respectively represent the object side surface S1 and the image side surface S2 of the first lens L1. That is, in the same lens, the surface with a smaller surface number is the object side surface, and the surface with a larger surface number is the image side surface. The Y radius in Table 1 is the curvature radius of the object side surface or the image side surface of the corresponding surface number on the optical axis. The absolute value of the first value in the "thickness" parameter column of the lens is the thickness of the lens on the optical axis, and the absolute value of the second value is the distance on the optical axis from the image side surface of the lens to the object side surface of the subsequent optical element. The optical axes of the lenses in the embodiments of the present application are on the same straight line, and this straight line serves as the optical axis of the optical system 10. It should be noted that in the following embodiments, the infrared cut-off filter 110 (i.e., the infrared filter in the table) can be an element in the optical system 10 or not, but in any case, the distance from the image side surface S14 of the seventh lens L7 to the imaging surface S15 should be included in the value of the thickness parameter corresponding to the infrared cut-off filter 110 in the table.

[0109] In the first embodiment, the effective focal length f of the optical system 10 is 7.41 mm, the f-number FNO is 2.2, the maximum field of view (i.e., the maximum viewing angle in the diagonal direction) FOV is 46.8°, the total optical length TTL is 7 mm, half of the diagonal length of the effective imaging area of the imaging surface S15 ImgH is 3.466 mm, and the maximum imaging circle diameter MIC is 6.932 mm.

[0110] In addition, in the parameter tables of the following embodiments (the first embodiment to the fifth embodiment), the reference wavelengths of the refractive index, Abbe number, and focal length of each lens are all 555 nm. In addition, the relational calculations and lens structures of each embodiment are based on the lens parameters (such as Table 1, Table 2, Table 3, Table 4, etc.).

[0111] Table 1

[0112]

[0113]

[0114] The focal lengths (mm) of each lens are as follows:

[0115] f1 f2 f3 f4 f5 f6 f7 3.317339 -8.06182 -11.8773 -39.0656 151.735 -10.199 39.055397

[0116] Table 2

[0117] Surface 2 3 4 5 6 7 9 K -2.141E+00 3.162E+01 9.900E+01 2.335E+00 6.716E+01 -5.078E+01 -6.428E+00 A4 2.840E-02 -2.504E-02 -8.590E-02 -8.861E-02 -2.727E-02 1.014E-01 -5.322E-02 A6 -2.793E-03 1.330E-01 2.742E-01 2.336E-01 1.473E-01 -6.070E-02 1.052E-03 A8 2.920E-03 -2.157E-01 -3.965E-01 -2.237E-01 2.429E-02 1.893E-01 -3.153E-01 A10 -3.139E-03 2.249E-01 4.044E-01 1.081E-01 -4.609E-01 -2.804E-01 1.273E+00 A12 2.206E-03 -1.603E-01 -2.889E-01 8.724E-02 1.073E+00 -5.033E-03 -3.151E+00 A14 -1.036E-03 7.656E-02 1.346E-01 -2.071E-01 -1.379E+00 7.512E-01 4.850E+00 A16 3.098E-04 -2.321E-02 -3.751E-02 1.538E-01 1.040E+00 -1.243E+00 -4.585E+00 A18 -5.567E-05 4.016E-03 5.324E-03 -5.378E-02 -4.329E-01 8.803E-01 2.442E+00 A20 4.600E-06 -3.004E-04 -2.415E-04 7.632E-03 7.723E-02 -2.465E-01 -5.678E-01 Surface 10 11 12 13 14 15 16 K -1.017E+01 -2.452E+01 5.640E+00 -3.525E+01 9.900E+01 3.348E+01 -1.123E+01 A4 -9.837E-03 2.300E-04 2.464E-05 6.089E-02 1.972E-01 5.828E-02 -2.262E-02 A6 9.276E-03 3.733E-05 1.358E-04 -1.584E-01 -2.673E-01 -5.124E-02 4.286E-03 A8 -1.856E-01 -5.896E-06 4.133E-05 1.427E-01 1.898E-01 4.492E-03 -5.049E-03 A10 5.672E-01 -1.368E-05 4.458E-06 -7.770E-02 -8.989E-02 9.916E-03 2.197E-03 A12 -9.822E-01 -9.631E-06 -2.753E-06 2.503E-02 2.880E-02 -5.153E-03 -2.979E-04 A14 1.047E+00 -4.300E-03 -6.069E-03 1.225E-03 -1.501E-05 A16 -6.706E-01 2.717E-04 7.951E-04 -1.618E-04 7.739E-06 A18 2.363E-01 1.777E-05 -5.796E-05 1.156E-05 -7.276E-07 A20 -3.498E-02 -2.504E-06 1.773E-06 -3.503E-07 2.313E-08

[0118] In the first embodiment, the optical system 10 satisfies the following relationships:

[0119] HFOV = 23.4°;

[0120] TTL / f = 0.945;

[0121] HFOV is half of the maximum field of view angle of the optical system 10, TTL is the distance from the object side surface S1 of the first lens L1 to the imaging surface S15 of the optical system 10 on the optical axis, and f is the effective focal length of the optical system 10. When the optical system 10 satisfies the above relationship of HFOV, it can have a small field of view and telephoto performance. When further satisfying the above relationship of TTL / f, the optical system 10 will have a shorter axial length under the condition of HFOV < 26°, so that it can be better applied to electronic products with a ultra-thin design and requiring telephoto performance. At the same time, under the condition of achieving telephoto, there is a good configuration between the overall optical length and the effective focal length of the optical system 10 that satisfies the above relationship, which is beneficial to further balance the chromatic aberration, spherical aberration and other aberrations during telephoto, thereby improving the imaging quality during telephoto. In addition, it can also maintain the miniaturized design of the system while balancing the system aberrations.

[0122] Y11 / Y72 = 0.628; Y11 is the maximum effective aperture of the object side surface S1 of the first lens L1, and Y72 is the maximum effective aperture of the image side surface S14 of the seventh lens L7. When satisfying the above relationship, the aperture ratio between the lens surfaces located at the most object side and the most image side of the system can be reasonably controlled, thereby suppressing the overall radial size of the optical system 10, and further reducing the volume of the optical system 10.

[0123] (n1 + n2) / f = 0.433mm -1 ; n1 is the refractive index of the first lens L1, and n2 is the refractive index of the second lens L2. When satisfying the above relationship, the proportion between the combined refractive power of the first lens L1 and the second lens L2 and the effective refractive power of the overall system can be reasonably allocated, which is beneficial to enhancing the light-gathering ability of the system and at the same time conducive to compressing the overall size of the system.

[0124] TTL / (ImgH*2) = 1.072; ImgH is half of the image height corresponding to the maximum field of view angle of the optical system 10. After assembling the image sensor, ImgH can also be understood as the distance from the center of the effective imaging area of the image sensor to the diagonal edge. When the above relationship is satisfied, the axial dimension of the optical system 10 and the dimension of the imaging surface S15 of the system will be reasonably configured, which is beneficial to shortening the axial dimension of the optical system 10, so that the optical system 10 with telephoto performance can be further miniaturized.

[0125] DL / TTL = 0.821; DL is the distance on the optical axis from the object side surface S1 of the first lens L1 to the image side surface S14 of the seventh lens L7. When the above relationship is satisfied, the structure in the optical system 10 can be reasonably arranged. On the basis of realizing miniaturization, it can also reduce the occupied space of the lens group, make the structure of the optical system 10 tend to be compact, and is beneficial to the layout of the module structure end.

[0126] (|T34| + |T45|) / CT4 = 2.819; T34 is the distance on the optical axis from the image side surface S6 of the third lens L3 to the object side surface S7 of the fourth lens L4, T45 is the distance on the optical axis from the image side surface S8 of the fourth lens L4 to the object side surface S9 of the fifth lens L5, and CT4 is the thickness of the fourth lens L4 on the optical axis. When the above relationship is satisfied, the distance between the third lens L3, the fourth lens L4 and the fifth lens L5 can be reasonably increased, so as to slow down the direction change of the light when it propagates between the third lens L3 and the fifth lens L5, suppress the deflection direction of the marginal rays of each field of view in the optical system, and further help to reduce the generation of astigmatism.

[0127] |f1 / f2| = 0.411; f1 is the effective focal length of the first lens L1, and f2 is the effective focal length of the second lens L2. When the above relationship is satisfied, the sizes and refractive powers of the first lens L1 and the second lens L2 are reasonably configured, which can balance the large spherical aberration generated by the first lens L1, improve the resolution of the overall optical lens, control the refractive power configuration at the rear end of the system, strengthen the correction of peripheral aberrations of the system, and at the same time, is beneficial to size compression and helps to form a small-sized optical lens.

[0128] |V2 - V1| = 36.5; V1 is the Abbe number of the first lens L1, and V2 is the Abbe number of the second lens L2. When the above relationship is satisfied, it is beneficial to correct the chromatic aberration of the system to improve the imaging quality.

[0129] (|f2| + |f3|) / |R71| = 0.843; where f2 is the effective focal length of the second lens L2, f3 is the effective focal length of the third lens L3, and R71 is the curvature radius of the object side surface S13 of the seventh lens L7 at the optical axis. When the above relationship is satisfied, the refractive power between the second lens L2 and the third lens L3 will be reasonably distributed, which helps to suppress the combined spherical aberration, chromatic aberration, and distortion of the first three lenses of the system, and reduces the design difficulty of the fourth lens L4 to the seventh lens L7. At the same time, through reasonable configuration with the refractive power of the second lens L2 and the third lens L3, the curvature distribution of the object side surface S13 of the seventh lens L7 is appropriate, which can avoid excessive bending of the surface shape, thus contributing to the molding and manufacturing of the lens.

[0130] (f1 + |f2| + |f3|) / f = 3.139; where f1 is the effective focal length of the first lens L1, f2 is the effective focal length of the second lens L2, and f3 is the effective focal length of the third lens L3. When the above relationship is satisfied, an appropriate ratio can be obtained between the effective focal lengths of the first lens L1, the second lens L2, and the third lens L3 and the effective focal length of the system, which can prevent the refractive power of the first three lenses of the system from being too strong, avoid large spherical aberration in the front lens group, and thus improve the overall resolution of the optical system 10; at the same time, when the above relationship is satisfied, it is also beneficial to compress the size of the first three lenses of the system, which helps to form a small-sized optical lens for the small-sized design of the system.

[0131] T23 / T12 = 3.14, where T12 is the distance on the optical axis from the image side surface S2 of the first lens L1 to the object side surface S3 of the second lens L2, and T23 is the distance on the optical axis from the image side surface S4 of the second lens L2 to the object side surface S5 of the third lens L3. When the above relationship is satisfied, the spacing distance between the first lens L1, the second lens L2, and the third lens L3 can be reasonably controlled, making the spatial arrangement between the lenses more uniform, and thus reducing the assembly difficulty.

[0132] In addition, Figure 2 Including the longitudinal spherical aberration diagram (Longitudinal Spherical Aberration) of the optical system 10, which represents the deviation of the convergence focal points of light rays of different wavelengths after passing through the lens. The ordinate of the longitudinal spherical aberration diagram represents the normalized pupil coordinate (Normalized Pupil Coordinator) from the center of the pupil to the edge of the pupil, and the abscissa represents the distance (in mm) from the imaging plane to the intersection point of the light ray and the optical axis. It can be seen from the longitudinal spherical aberration diagram that the deviation degree of the convergence focal points of light rays of each wavelength in the first embodiment tends to be consistent, and the blur spots or chromatic halos in the imaging picture are effectively suppressed. Figure 2It also includes the astigmatic field curves of the optical system 10, where the S curve represents the sagittal field curve at 555 nm, and the T curve represents the meridional field curve at 555 nm. As can be seen from the figure, the field curvature of the system is small, and the field curvature and astigmatism of each field of view are well corrected, and clear imaging is achieved at both the center and edges of the field of view. Figure 2 It also includes the distortion diagram (DISTORTION) of the optical system 10. As can be seen from the figure, the image distortion caused by the chief ray is small, and the imaging quality of the system is excellent.

[0133] Second Embodiment

[0134] Reference Figure 3 and Figure 4 In the second embodiment, the optical system 10 sequentially includes an aperture stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with negative refractive power, a fourth lens L4 with positive refractive power, a fifth lens L5 with negative refractive power, a sixth lens L6 with negative refractive power, and a seventh lens L7 with positive refractive power from the object side to the image side. Figure 4 It includes the longitudinal spherical aberration diagram, astigmatism diagram, and distortion diagram of the optical system 10 in the second embodiment, where the reference wavelengths of the astigmatism diagram and distortion diagram are 555 nm.

[0135] The object side surface S1 of the first lens L1 is convex at the paraxial region and convex at the circumference; the image side surface S2 is convex at the paraxial region and convex at the circumference.

[0136] The object side surface S3 of the second lens L2 is convex at the paraxial region and concave at the image side; the object side surface S3 is convex at the circumference and concave at the image side.

[0137] The object side surface S5 of the third lens L3 is convex at the paraxial region and concave at the image side; the object side surface S5 is convex at the circumference and concave at the image side.

[0138] The object side surface S7 of the fourth lens L4 is concave at the paraxial region and convex at the image side; the object side surface S7 is concave at the circumference and convex at the image side.

[0139] The object side surface S9 of the fifth lens L5 is concave at the paraxial region and convex at the image side; the object side surface S9 is concave at the circumference and convex at the image side.

[0140] The object side surface S11 of the sixth lens L6 is concave at the paraxial region and convex at the image side; the object side surface S11 is concave at the circumference and convex at the image side.

[0141] The object side surface S13 of the seventh lens L7 is concave at the paraxial region, and the image side surface S14 is convex at the paraxial region; the object side surface S13 is concave at the circumferential region, and the image side surface S14 is convex at the circumferential region.

[0142] In addition, the lens parameters of the optical system 10 in the second embodiment are given in Table 3 and Table 4, where the definitions of each structure and parameter can be obtained from the first embodiment and will not be elaborated here.

[0143] Table 3

[0144]

[0145]

[0146] The focal lengths (mm) of each lens are as follows:

[0147] f1 f2 f3 f4 f5 f6 f7 3.319978 -7.50268 -11.8972 47.54521 -15.2008 -20.5422 250.001838

[0148] Table 4

[0149] Surface 2 3 4 5 6 7 9 K -2.099E+00 3.140E+01 9.900E+01 3.275E+00 5.325E+01 -5.441E+01 2.321E-02 A4 2.748E-02 -2.442E-02 -9.179E-02 -9.381E-02 -3.185E-02 9.312E-02 -6.634E-02 A6 -3.809E-04 1.067E-01 2.740E-01 2.634E-01 1.456E-01 -3.270E-02 3.493E-02 A8 -1.867E-03 -1.357E-01 -3.535E-01 -2.900E-01 9.694E-02 1.146E-01 -2.864E-01 A10 2.589E-03 1.042E-01 3.165E-01 2.506E-01 -6.880E-01 -1.613E-01 7.090E-01 A12 -1.770E-03 -5.207E-02 -2.085E-01 -1.605E-01 1.376E+00 5.031E-02 -1.152E+00 A14 6.532E-04 1.663E-02 9.674E-02 5.750E-02 -1.572E+00 1.055E-01 1.150E+00 A16 -1.233E-04 -3.110E-03 -2.934E-02 -8.515E-03 1.067E+00 -1.075E-01 -6.699E-01 A18 7.143E-06 2.748E-04 5.204E-03 4.218E-05 -4.036E-01 1.333E-02 1.861E-01 A20 4.586E-07 -4.297E-06 -4.103E-04 2.700E-05 6.624E-02 1.126E-02 -1.234E-02 Surface 10 11 12 13 14 15 16 K -6.524E+00 -2.210E+01 1.189E+00 -4.382E+01 2.899E+01 6.005E+01 5.160E+01 A4 -9.479E-03 1.889E-03 8.906E-04 4.859E-02 1.707E-01 6.577E-02 -1.519E-02 A6 1.339E-02 1.050E-03 6.232E-04 -1.240E-01 -2.245E-01 -6.644E-02 -5.986E-04 A8 -1.468E-01 3.415E-04 2.694E-04 1.076E-01 1.466E-01 2.151E-02 2.923E-05 A10 3.577E-01 1.030E-04 4.658E-05 -5.444E-02 -6.092E-02 -5.824E-04 -2.068E-04 A12 -5.503E-01 2.933E-05 -1.281E-05 1.569E-02 1.642E-02 -1.441E-03 2.175E-04 A14 5.585E-01 -2.375E-03 -2.784E-03 4.388E-04 -6.638E-05 A16 -3.569E-01 1.402E-04 2.737E-04 -6.183E-05 9.633E-06 A18 1.303E-01 4.788E-06 -1.276E-05 4.446E-06 -7.072E-07 A20 -2.048E-02 -7.162E-07 1.323E-07 -1.315E-07 2.140E-08

[0150] The imaging module 10 in this embodiment satisfies the following relationship:

[0151] TTL / (ImgH*2) 1.133 Y11 / Y72 0.689 HFOV 22.100 |V2-V1| 36.500 DL / TTL 0.818 (n1+n2) / f 0.408 TTL / f 0.943 (|f2|+|f3|) / |R71| 0.824 |f1 / f2| 0.443 (f1+|f2|+|f3|) / f 2.894 (|T34|+|T45|) / CT4 2.406 T23 / T12 2.96

[0152] From Figure 4 the aberration diagrams, it can be seen that the longitudinal spherical aberration, field curvature and distortion of the optical system 10 are all well controlled, so that the optical system 10 in this embodiment has good imaging quality.

[0153] Third Embodiment

[0154] Referring to Figure 5 and Figure 6 , in the third embodiment, the optical system 10 includes, in order from the object side to the image side, an aperture stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with positive refractive power, a fourth lens L4 with negative refractive power, a fifth lens L5 with positive refractive power, a sixth lens L6 with negative refractive power, and a seventh lens L7 with positive refractive power. Figure 6 Including the longitudinal spherical aberration diagram, astigmatism diagram and distortion diagram of the optical system 10 in the third embodiment, where the reference wavelengths of the astigmatism diagram and distortion diagram are 555 nm.

[0155] The object side surface S1 of the first lens L1 is convex at the paraxial region, and the image side surface S2 is convex at the paraxial region; the object side surface S1 is convex at the circumferential region, and the image side surface S2 is concave at the circumferential region.

[0156] The object side surface S3 of the second lens L2 is convex at the paraxial region and concave at the peripheral region; the image side surface S4 is concave at the paraxial region and convex at the peripheral region.

[0157] The object side surface S5 of the third lens L3 is concave at the paraxial region and convex at the peripheral region; the image side surface S6 is convex at the paraxial region and concave at the peripheral region.

[0158] The object side surface S7 of the fourth lens L4 is convex at the paraxial region and concave at the peripheral region; the image side surface S8 is concave at the paraxial region and convex at the peripheral region.

[0159] The object side surface S9 of the fifth lens L5 is concave at the paraxial region and convex at the peripheral region; the image side surface S10 is convex at the paraxial region and concave at the peripheral region.

[0160] The object side surface S11 of the sixth lens L6 is concave at the paraxial region and concave at the peripheral region; the image side surface S12 is concave at the paraxial region and convex at the peripheral region.

[0161] The object side surface S13 of the seventh lens L7 is concave at the paraxial region and convex at the peripheral region; the image side surface S14 is convex at the paraxial region and convex at the peripheral region.

[0162] In addition, the lens parameters of the optical system 10 in the third embodiment are given in Table 5 and Table 6, where the definitions of each structure and parameter can be obtained from the first embodiment and will not be elaborated here.

[0163] Table 5

[0164]

[0165] The focal lengths (mm) of each lens are as follows:

[0166] f1 f2 f3 f4 f5 f6 f7 3.510199 -4.53251 14.7037 -19.9192 101.4276 -8.34073 26.484288

[0167] Table 6

[0168] Surface 2 3 4 5 6 7 9 K -1.763E+00 -7.037E+01 -4.492E+01 -5.775E+00 -9.900E+01 -5.760E+01 4.376E+00 A4 2.677E-02 3.831E-02 -1.875E-02 -5.668E-03 8.545E-02 8.955E-02 -7.169E-02 A6 8.067E-04 -5.953E-03 2.347E-02 6.418E-03 2.125E-02 9.356E-02 1.277E-01 A8 -7.679E-04 -3.140E-02 -8.684E-02 4.343E-02 -3.640E-02 -4.774E-02 -5.152E-02 A10 3.091E-03 5.761E-02 1.617E-01 -3.631E-01 -1.741E-01 -3.334E-01 -2.258E-01 A12 -3.635E-03 -5.445E-02 -1.639E-01 9.441E-01 5.086E-01 1.086E+00 7.494E-01 A14 2.429E-03 3.112E-02 1.026E-01 -1.279E+00 -6.920E-01 -1.516E+00 -9.526E-01 A16 -9.361E-04 -1.086E-02 -3.954E-02 9.825E-01 4.874E-01 1.072E+00 6.112E-01 A18 1.963E-04 2.132E-03 8.643E-03 -4.061E-01 -1.694E-01 -3.756E-01 -1.989E-01 A20 -1.759E-05 -1.803E-04 -8.137E-04 7.077E-02 2.302E-02 5.154E-02 2.619E-02 Surface 10 11 12 13 14 15 16 K -8.317E+01 1.476E+00 -1.132E-01 -1.177E+00 2.664E+01 9.900E+01 -9.900E+01 A4 -1.565E-02 -9.698E-04 2.091E-04 -2.163E-02 -3.215E-03 -8.349E-03 -2.625E-02 A6 -1.916E-02 1.115E-03 -7.230E-04 -1.487E-02 -1.844E-02 5.085E-03 4.317E-03 A8 1.834E-01 3.643E-04 -1.426E-04 7.066E-03 9.140E-03 -4.939E-03 -1.103E-03 A10 -4.276E-01 6.884E-05 -6.572E-06 -1.036E-04 -4.022E-03 1.541E-03 6.283E-04 A12 6.364E-01 1.041E-06 4.166E-06 -7.333E-04 1.536E-03 -1.765E-05 -3.007E-04 A14 -5.843E-01 1.738E-04 -3.959E-04 -9.547E-05 8.445E-05 A16 3.232E-01 7.261E-06 5.895E-05 2.235E-05 -1.345E-05 A18 -9.868E-02 -6.001E-06 -4.465E-06 -2.077E-06 1.127E-06 A20 1.267E-02 4.847E-07 1.300E-07 7.065E-08 -3.835E-08

[0169] The imaging module 10 in this embodiment satisfies the following relationships:

[0170] TTL / (ImgH*2) 1.079 Y11 / Y72 0.632 HFOV 23.800 |V2-V1| 35.700 DL / TTL 0.851 (n1+n2) / f 0.441 TTL / f 0.971 (|f2|+|f3|) / |R71| 0.263 |f1 / f2| 0.774 (f1+|f2|+|f3|) / f 3.133 (|T34|+|T45|) / CT4 2.090 T23 / T12 2.47

[0171] From Figure 6 the aberration diagram, it can be seen that the longitudinal spherical aberration, field curvature and distortion of the optical system 10 are all well controlled, so that the optical system 10 in this embodiment has good imaging quality.

[0172] Fourth Embodiment

[0173] Reference Figure 7 and Figure 8 In the fourth embodiment, the optical system 10 includes, in order from the object side to the image side, an aperture stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with positive refractive power, a fourth lens L4 with positive refractive power, a fifth lens L5 with negative refractive power, a sixth lens L6 with negative refractive power, and a seventh lens L7 with positive refractive power. Figure 8 Including the longitudinal spherical aberration diagram, astigmatism diagram, and distortion diagram of the optical system 10 in the fourth embodiment, where the reference wavelengths for the astigmatism diagram and distortion diagram are 555 nm.

[0174] The object side surface S1 of the first lens L1 is convex at the paraxial region and convex at the periphery; the image side surface S2 is convex at the paraxial region and convex at the periphery.

[0175] The object side surface S3 of the second lens L2 is convex at the paraxial region and concave at the periphery; the image side surface S4 is convex at the paraxial region and concave at the periphery.

[0176] The object side surface S5 of the third lens L3 is convex at the paraxial region and convex at the periphery; the image side surface S6 is convex at the paraxial region and concave at the periphery.

[0177] The object side surface S7 of the fourth lens L4 is convex at the paraxial region and concave at the periphery; the image side surface S8 is convex at the paraxial region and concave at the periphery.

[0178] The object side surface S9 of the fifth lens L5 is concave at the paraxial region and convex at the periphery; the image side surface S10 is concave at the paraxial region and convex at the periphery.

[0179] The object side surface S11 of the sixth lens L6 is concave at the paraxial region and concave at the periphery; the image side surface S12 is concave at the paraxial region and convex at the periphery.

[0180] The object side surface S13 of the seventh lens L7 is convex at the paraxial region and concave at the periphery; the image side surface S14 is concave at the paraxial region and convex at the periphery.

[0181] In addition, the lens parameters of the optical system 10 in the fourth embodiment are given in Tables 7 and 8, where the definitions of each structure and parameter can be obtained from the first embodiment and will not be elaborated here.

[0182] Table 7

[0183]

[0184] The focal lengths (mm) of each lens are as follows:

[0185] f1 f2 f3 f4 f5 f6 f7 3.511764 -4.40058 23.6221 187.1399 -203.173 -8.52818 32.41513

[0186] Table 8

[0187]

[0188]

[0189] The imaging module 10 in this embodiment satisfies the following relationship:

[0190] TTL / (ImgH*2) 1.049 Y11 / Y72 0.625 HFOV 25.000 |V2-V1| 35.700 DL / TTL 0.854 (n1+n2) / f 0.464 TTL / f 0.993 (|f2|+|f3|) / |R71| 1.495 |f1 / f2| 0.798 (f1+|f2|+|f3|) / f 4.570 (|T34|+|T45|) / CT4 1.959 T23 / T12 2.43

[0191] From Figure 8 the aberration diagram, it can be seen that the longitudinal spherical aberration, field curvature and distortion of the optical system 10 are all well controlled, so that the optical system 10 in this embodiment has good imaging quality.

[0192] The Fifth Embodiment

[0193] Refer to Figure 9 and Figure 10 , in the fifth embodiment, the optical system 10 sequentially includes an aperture stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with positive refractive power, a fourth lens L4 with positive refractive power, a fifth lens L5 with positive refractive power, a sixth lens L6 with positive refractive power, and a seventh lens L7 with negative refractive power from the object side to the image side. Figure 10 Including the longitudinal spherical aberration diagram, astigmatism diagram and distortion diagram of the optical system 10 in the fifth embodiment, and the reference wavelength of the astigmatism diagram and distortion diagram therein is 555 nm.

[0194] The object side surface S1 of the first lens L1 is convex at the paraxial region and convex at the circumference; the image side surface S2 is convex at the paraxial region and convex at the circumference.

[0195] The object side surface S3 of the second lens L2 is convex at the paraxial region and concave at the image side; the object side surface S3 is convex at the circumference and the image side surface S4 is concave at the circumference.

[0196] The object side surface S5 of the third lens L3 is convex at the paraxial region and concave at the image side; the object side surface S5 is convex at the circumference and the image side surface S6 is concave at the circumference.

[0197] The object side surface S7 of the fourth lens L4 is convex at the paraxial region and concave at the image side; the object side surface S7 is concave at the circumference and the image side surface S8 is convex at the circumference.

[0198] The object side S9 of the fifth lens L5 is concave at the paraxial region and convex at the peripheral region; the image side S10 is convex at the paraxial region and convex at the peripheral region.

[0199] The object side S11 of the sixth lens L6 is convex at the paraxial region and convex at the peripheral region; the image side S12 is convex at the paraxial region and concave at the peripheral region.

[0200] The object side S13 of the seventh lens L7 is concave at the paraxial region and convex at the peripheral region; the image side S14 is convex at the paraxial region and convex at the peripheral region.

[0201] In addition, the lens parameters of the optical system 10 in the fourth embodiment are given in Tables 9 and 10, where the definitions of the various structures and parameters can be obtained from the first embodiment and will not be elaborated here.

[0202] Table 9

[0203]

[0204] The focal lengths (mm) of the respective lenses are as follows:

[0205] f1 f2 f3 f4 f5 f6 f7 5.661014 -8.24034 61.81833 29.1797 38.4318 64.50972 -8.716148

[0206] Table 10

[0207]

[0208]

[0209] The imaging module 10 in this embodiment satisfies the following relationships:

[0210] TTL / (ImgH*2) 1.324 Y11 / Y72 0.851 HFOV 22.300 |V2-V1| 36.500 DL / TTL 0.896 (n1+n2) / f 0.410 TTL / f 1.106 (|f2|+|f3|) / |R71| 17.546 |f1 / f2| 0.687 (f1+|f2|+|f3|) / f 9.683 (|T34|+|T45|) / CT4 2.35 T23 / T12 2.02

[0211] From Figure 10 the aberration diagram, it can be seen that the longitudinal spherical aberration, field curvature, and distortion of the optical system 10 are all well controlled, so that the optical system 10 in this embodiment has good imaging quality.

[0212] Reference Figure 11, some embodiments of the present application further provide an imaging module 20, which may include the optical system 10 of any of the above embodiments and an image sensor 210. The image sensor 210 is disposed on the image side of the optical system 10. The image sensor 210 may be a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). Generally, during assembly, the imaging surface S15 of the optical system 10 overlaps with the photosensitive surface of the image sensor 210.

[0213] In some embodiments, the imaging module 20 includes an infrared cut-off filter 110 disposed between the seventh lens L7 and the image sensor 210. The infrared cut-off filter 110 is used to filter out infrared light. In some embodiments, the infrared cut-off filter 110 may be mounted to the image end of the lens. In some embodiments, the imaging module 20 further includes a protective glass disposed between the infrared cut-off filter and the image sensor 210, and the protective glass is used to protect the image sensor 210.

[0214] By adopting the above optical system 10, the imaging module 20 not only can have telephoto performance, but also can have a smaller axial dimension and good imaging quality.

[0215] Reference Figure 12 , some embodiments of the present application further provide an electronic device 30. The imaging module 20 is applied to the electronic device 30 to enable it to have excellent telephoto performance. Specifically, the electronic device 30 includes a fixing member 310, and the imaging module 20 is mounted on the fixing member 310. The fixing member 310 may be components such as a circuit board, a middle frame, and a rear cover. The electronic device 30 may be, but is not limited to, a smart phone, a smart watch, smart glasses, an e-book reader, a vehicle-mounted imaging device, a monitoring device, a drone, a medical device (such as an endoscope), a tablet computer, a biometric device (such as a fingerprint recognition device or a pupil recognition device, etc.), a PDA (Personal Digital Assistant), a drone, etc. By adopting the above imaging module 20, the electronic device 30 will have excellent telephoto performance, so that it can achieve good shooting of distant scenes, and at the same time, it can also prevent the axial dimension of the module from imposing a large limitation on the reduction of the thickness of the device, which is beneficial to realizing a thin and light design.

[0216] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0217] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. An optical system, characterized in that, it has a total of seven refractive lenses, which successively include from the object side to the image side: a first lens with positive refractive power, the object side of the first lens is convex at the paraxial region, and the image side is convex at the paraxial region; a second lens with negative refractive power, the object side of the second lens is convex at the paraxial region, and the image side is concave at the paraxial region; a third lens with refractive power; a fourth lens with refractive power; a fifth lens with refractive power, the object side of the fifth lens is concave at the paraxial region, and the image side is convex at the paraxial region; a sixth lens with refractive power; a seventh lens with refractive power; and the optical system satisfies the relations: 20° < HFOV < 26°; 0.625 ≤ Y11 / Y72 < 1; (|T34| + |T45|) / CT4 ≥ 1.959; HFOV is half of the maximum field of view angle of the optical system, Y11 is the maximum effective aperture of the object side of the first lens, Y72 is the maximum effective aperture of the image side of the seventh lens, T34 is the distance on the optical axis from the image side of the third lens to the object side of the fourth lens, T45 is the distance on the optical axis from the image side of the fourth lens to the object side of the fifth lens, and CT4 is the thickness of the fourth lens on the optical axis.

2. The optical system according to claim 1, characterized in that, the optical system satisfies the relation: (n1 + n2) / f < 0.5 mm -1 ; n1 is the refractive index of the first lens, and n2 is the refractive index of the second lens.

3. The optical system according to claim 1, characterized in that, the optical system satisfies the relation: 1.0 < TTL / (ImgH 2) < 1.5; ImgH is half of the image height corresponding to the maximum field of view angle of the optical system.

4. The optical system according to claim 1, characterized in that, the optical system satisfies the relation: 0.8 < DL / TTL < 1; DL is the distance on the optical axis from the object side of the first lens to the image side of the seventh lens.

5. The optical system according to claim 1, characterized in that, the optical system satisfies the relation: 0.9 < TTL / f < 1.2; TTL is the distance on the optical axis from the object side of the first lens to the imaging plane of the optical system, and f is the effective focal length of the optical system.

6. The optical system according to claim 1, characterized in that, the optical system satisfies the relation: 0.4 < |f1 / f2| < 1; f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens.

7. The optical system according to claim 1, characterized in that, the optical system satisfies the relation: |V2 - V1| > 30; V1 is the Abbe number of the first lens, and V2 is the Abbe number of the second lens.

8. The optical system according to claim 1, characterized in that, the optical system satisfies the relation: (|f2| + |f3|) / |R71| < 20; f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, and R71 is the curvature radius of the object side of the seventh lens on the optical axis.

9. The optical system according to claim 1, characterized in that, The optical system satisfies the relationship: 2.894 ≤ (f1 + |f2| + |f3|) / f < 10; where f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, and f3 is the effective focal length of the third lens.

10. The optical system according to claim 1, wherein, the optical system satisfies the relationship: 2 < T23 / T12 < 3.2; where T12 is the distance on the optical axis from the image side surface of the first lens to the object side surface of the second lens, and T23 is the distance on the optical axis from the image side surface of the second lens to the object side surface of the third lens.

11. An imaging module, wherein, it includes an image sensor and the optical system according to any one of claims 1 to 10, and the image sensor is disposed on the image side of the optical system.

12. An electronic device, wherein, it includes the imaging module according to claim 11.

Images