Optical systems, imaging modules and electronic equipment

Abstract

The present invention relates to an optical system, an imaging module and an electronic device. The optical system includes, from the object side to the image side, in sequence: a first lens with positive refractive power, the object side surface is convex at the paraxial position; a second lens with negative refractive power, the object side surface is convex at the paraxial position, and the image side surface is concave at the paraxial position; a third lens with refractive power; a fourth lens with refractive power; a fifth lens with refractive power; a sixth lens with refractive power; a seventh lens with refractive power, the object side surface is concave at the paraxial position; the optical system satisfies the conditional formula: f*43 / (ImgH*FNO)<25; f is the effective focal length of the optical system, ImgH is half of the diagonal length of the effective pixel area of ​​the optical system on the imaging plane, and FNO is the aperture number of the optical system. The above optical system can also have excellent imaging quality when imaging distant objects or in dark environments.

Description

Technical Field

[0001] The present invention relates to the field of photography, and in particular to an optical system, an imaging module and electronic equipment. Background Art

[0002] With the rapid popularization of electronic devices with camera functions such as smart phones and tablets, users have higher and higher requirements for the camera performance of electronic devices, especially when electronic devices can have excellent image quality in low-light environments and meet the requirements of high image quality in different environments. However, the images taken by traditional electronic devices in low-light environments have low brightness and unclear images, which makes it difficult to meet the requirements of high image quality. Summary of the invention

[0003] Based on this, it is necessary to provide an optical system, an imaging module and an electronic device to address the problem that current electronic devices do not have clear imaging in dark environments and are difficult to meet the requirements of high imaging quality.

[0004] An optical system, comprising, from the object side to the image side, the following:

[0005] A first lens having positive refractive power, wherein the object side surface of the first lens is convex at the paraxial position;

[0006] a second lens having negative refractive power, wherein the object side surface of the second lens is convex at the paraxial position, and the image side surface of the second lens is concave at the paraxial position;

[0007] a third lens having refractive power;

[0008] a fourth lens having a refractive power;

[0009] a fifth lens having refractive power;

[0010] a sixth lens having a refractive power;

[0011] a seventh lens having refractive power, wherein the object side surface of the seventh lens is concave at the paraxial position;

[0012] And the optical system satisfies the following conditional formula:

[0013] f*43 / (ImgH*FNO)<25;

[0014] Wherein, f is the effective focal length of the optical system, ImgH is the diagonal length of the effective pixel area of ​​the optical system on the imaging plane, and FNO is the aperture number of the optical system.

[0015] The above conditional formula is the equivalent focal length of the optical system calculated based on the full frame, and generally, an optical system with an equivalent focal length greater than 50mm has a certain telephoto performance. When the above conditional formula is met, the magnification capability of the optical system is greater than twice that of an optical system with an equivalent focal length of 25mm, and the value of ImgH is large, so that the optical system can adapt to larger size and higher pixel photosensitive elements, thereby improving the imaging clarity of the optical system. In addition, when the above conditional formula is met, the effective focal length of the optical system, the diagonal length of the effective pixel area on the imaging surface, and the aperture number can be reasonably configured, so that the optical system has a larger magnification, so that the system can achieve a close-up shooting effect for a distant subject. In addition, compared with a general system with the same magnification, the optical system has a larger aperture to increase the luminous flux of the optical system, so that the optical system can also have excellent imaging quality in an environment with insufficient light.

[0016] In one embodiment, the optical system satisfies the following condition:

[0017] 1.9≤(|R32|+|R42|) / f≤7.2;

[0018] Wherein, R32 is the radius of curvature of the image side surface of the third lens at the optical axis, and R42 is the radius of curvature of the image side surface of the fourth lens at the optical axis. The third lens provides positive or negative refractive power for the optical system, and the fourth lens provides positive or negative refractive power for the optical system. The combination of the third lens and the fourth lens can better correct the distortion and coma produced by the lenses on the object side of the third lens. When the above conditional formula is met, the radius of curvature of the image side surface of the third lens and the image side surface of the fourth lens at the optical axis and the effective focal length of the optical system can be reasonably configured to avoid the image side surfaces of the third lens and the fourth lens being too curved or too flat, resulting in a large spherical aberration or vertical axis chromatic aberration in the optical system, which is beneficial to the reasonable distribution of primary aberrations in the lenses of the optical system and reduces the tolerance sensitivity of the optical system.

[0019] In one embodiment, the optical system satisfies the following condition:

[0020] 5≤(|f2|+|f3|) / R31≤22;

[0021] Wherein, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, and R31 is the radius of curvature of the object side of the third lens at the optical axis. The second lens provides negative refractive power for the optical system, and the third lens provides positive or negative refractive power for the optical system. When the above conditional formula is satisfied, the second lens and the third lens as a whole can offset the primary aberration generated by the first lens; at the same time, the effective focal lengths of the second lens and the third lens and the radius of curvature of the object side of the third lens at the paraxial position can be reasonably configured to avoid the second lens and the third lens from generating large spherical aberration and vertical axis chromatic aberration to the optical system, which is beneficial to the reasonable distribution of primary aberrations in each lens of the optical system and reduces the tolerance sensitivity of the optical system.

[0022] In one embodiment, the optical system satisfies the following condition:

[0023] f / f1≤2;

[0024] Wherein, f1 is the effective focal length of the first lens. When the above conditional formula is satisfied, the effective focal length of the first lens and the effective focal length of the optical system can be reasonably configured, so that the refractive power of the first lens in the optical system is moderate, so as to effectively reduce the generation of chromatic aberration and spherical aberration, thereby improving the imaging quality of the optical system, and helping to reduce the sensitivity of the optical system. At the same time, while maintaining the miniaturized design of the optical system, the optical system can also have a telephoto characteristic.

[0025] In one embodiment, the fourth lens has positive refractive power, at least one of the object-side surface or the image-side surface of the fifth lens has an inflection point, and the optical system satisfies the following conditional formula:

[0026] |R41 / R51|≤1;

[0027] Wherein, R41 is the radius of curvature of the object side surface of the fourth lens at the optical axis, and R51 is the radius of curvature of the object side surface of the fifth lens at the optical axis. When the above conditional formula is met, the values ​​of R41 and R51 can be reasonably configured to ensure that the object side surface of the fourth lens and the object side surface of the fifth lens can reasonably distribute the refractive power in the vertical direction, thereby suppressing the aberration of the optical system and facilitating reducing the size of the diffuse spot in the optical system.

[0028] In one embodiment, the optical system satisfies the following condition:

[0029] f≥7.2mm;

[0030] TTL≤7mm;

[0031] TTL / f≤1.0;

[0032] Wherein, TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis. When the conditional formula is satisfied: f≥7.2mm, it is beneficial for the optical system to cooperate with the photosensitive element and have a long focal length characteristic. Moreover, when the above conditional formula is satisfied, when TTL≤7mm, the optical system can have a long focal length, which is beneficial for the installation of the optical system in a miniaturized electronic device. In addition, when the above conditional formula is satisfied, it is beneficial to correct aberrations such as chromatic aberration, spherical aberration and distortion of the optical system, and improve the imaging quality of the optical system.

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

[0034] 4≤(|f1|+|f2|+|f3|) / f≤27;

[0035] Wherein, 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. The first lens, the second lens, and the third lens constitute the front lens group of the optical system. When the above conditional formula is satisfied, the effective focal lengths of the first lens, the second lens, the third lens, and the optical system can be reasonably configured to avoid large aberrations of the front lens group, thereby improving the imaging quality of the optical system, and at the same time, it is also beneficial to shorten the size of the front lens group in the optical axis direction, thereby shortening the total length of the optical system and realizing a miniaturized design.

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

[0037] 6≤TTL / (CT23+CT45)≤8.3;

[0038] Wherein, TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis, CT23 is the distance from the image side of the second lens to the object side of the third lens on the optical axis, and CT45 is the distance from the image side of the fourth lens to the object side of the fifth lens on the optical axis. When the above conditional expressions are met, the arrangement between the third lens and the fourth lens can be made more compact, thereby making the third lens and the fourth lens become the transition part of the light deflection in the optical system, even if the refractive power of the third lens and the fourth lens in the optical system is small, thereby reducing the sensitivity of the optical system to the distance between the third lens and the fourth lens.

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

[0040] -0.5≤|R41| / f4≤0.2;

[0041] Wherein, R41 is the radius of curvature of the object side of the fourth lens at the optical axis, and f4 is the effective focal length of the fourth lens. When the above conditional formula is satisfied, the radius of curvature of the object side of the fourth lens at the optical axis and the effective focal length of the fourth lens can be reasonably configured, so that the surface complexity of the fourth lens is reduced, which is beneficial to suppress the distortion of the optical system and the generation of field curvature in the meridian direction, so as to improve the imaging quality of the optical system, and also beneficial to reduce the difficulty of molding the fourth lens.

[0042] An imaging module comprises a photosensitive element and the optical system described in any of the above embodiments, wherein the photosensitive element is arranged on the image side of the optical system. The use of the above optical system in the imaging module can enhance the magnification capability of the imaging module, so that the optical system can adapt to photosensitive elements of larger size and higher pixel, thereby improving the imaging quality of the optical system. In addition, the imaging module can also have excellent imaging quality when imaging a distant subject, and can also improve the imaging quality of the imaging module in a dark environment.

[0043] An electronic device comprises a housing and the above-mentioned imaging module, wherein the imaging module is arranged in the housing. The above-mentioned imaging module is adopted in the electronic device, and the imaging quality of the electronic device can be improved by enhancing the magnification capability of the optical system. In addition, it is beneficial for the electronic device to have excellent imaging quality when imaging a distant subject, and it can also improve the imaging quality of the electronic device in a dark environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a schematic diagram of an optical system in a first embodiment of the present application;

[0045] Figure 2 The spherical aberration diagram, astigmatism diagram and distortion diagram of the optical system in the first embodiment of the present application;

[0046] Figure 3 is a schematic diagram of an optical system in a second embodiment of the present application;

[0047] Figure 4 The spherical aberration diagram, astigmatism diagram and distortion diagram of the optical system in the second embodiment of the present application;

[0048] Figure 5 is a schematic diagram of an optical system in a third embodiment of the present application;

[0049] Figure 6The spherical aberration diagram, astigmatism diagram and distortion diagram of the optical system in the third embodiment of the present application;

[0050] Figure 7 is a schematic diagram of an optical system in a fourth embodiment of the present application;

[0051] Figure 8 The spherical aberration diagram, astigmatism diagram and distortion diagram of the optical system in the fourth embodiment of the present application;

[0052] Fig. 9 is a schematic diagram of an optical system in a fifth embodiment of the present application;

[0053] Fig.10 The spherical aberration diagram, astigmatism diagram and distortion diagram of the optical system in the fifth embodiment of the present application;

[0054] Fig.11 is a schematic diagram of an imaging module in an embodiment of the present application;

[0055] Fig.12 It is a schematic diagram of an electronic device in an embodiment of the present application. DETAILED DESCRIPTION

[0056] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of 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 violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0057] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0058] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0059] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0060] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0061] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0062] See also Figure 1 In some embodiments of the present application, the optical system 100 includes, from the object side to the image side, 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. Specifically, 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.

[0063] Among them, the first lens L1 has a positive refractive power, which helps to shorten the total length of the optical system 100, and the object side surface S1 of the first lens L1 is a convex surface at the paraxial position, which can further enhance the positive refractive power of the first lens L1, so that the size of the optical system 100 in the optical axis direction becomes shorter, which is conducive to the miniaturization design of the optical system 100. The second lens L2 has a negative refractive power, and the object side surface S3 of the second lens L2 is a convex surface at the paraxial position, and the image side surface S4 is a concave surface at the paraxial position. The third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 all have refractive power. The seventh lens L7 has a refractive power, and the object side surface S13 of the seventh lens L7 is a concave surface at the paraxial position.

[0064] In addition, in some embodiments, the optical system 100 is provided with an aperture STO, which can be provided on the object side of the first lens L1. In some embodiments, the optical system 100 further includes an infrared filter L8 provided on the image side of the seventh lens L7, and the infrared filter L8 includes an object side surface S15 and an image side surface S16. Further, the optical system 100 further includes an image plane S17 located on the image side of the seventh lens L7, and the image plane S17 is the imaging plane of the optical system 100. The incident light can be imaged on the image plane S17 after being adjusted by the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7. It is worth noting that the infrared filter L8 can be an infrared cut-off filter, which is used to filter out interference light and prevent the interference light from reaching the image plane S17 of the optical system 100 and affecting normal imaging.

[0065] In some embodiments, the object side and image side of each lens of the optical system 100 are both aspherical. The use of aspherical structures can improve the flexibility of lens design, effectively correct spherical aberration, and improve imaging quality. In other embodiments, the object side and image side of each lens of the optical system 100 can also be spherical. It should be noted that the above embodiments are only examples of some embodiments of the present application. In some embodiments, the surface of each lens in the optical system 100 can be any combination of aspherical or spherical surfaces.

[0066] In some embodiments, the material of each lens in the optical system 100 can be glass or plastic. The use of plastic lenses can reduce the weight of the optical system 100 and reduce the production cost, and can achieve a lightweight and compact design of the optical system in conjunction with the smaller size of the optical system. The use of glass lenses enables the optical system 100 to have excellent optical performance and high temperature resistance. It should be noted that the material of each lens in the optical system 100 can also be any combination of glass and plastic, and does not necessarily have to be glass or plastic.

[0067] It should be noted that the first lens L1 does not mean that there is only one lens. In some embodiments, there may be two or more lenses in the first lens L1. The two or more lenses can form a cemented lens. The surface of the cemented lens closest to the object side can be regarded as the object side surface S1, and the surface closest to the image side can be regarded as the image side surface S2. Alternatively, the lenses in the first lens L1 do not form a cemented lens, but the distances between the lenses are relatively fixed. In this case, the object side surface of the lens closest to the object side is the object side surface S1, and the image side surface of the lens closest to the image side is the image side surface S2. In addition, in some embodiments, the number of lenses in the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, or the seventh lens L7 may be greater than or equal to two, and any adjacent lenses may form a cemented lens or a non-cemented lens.

[0068] Further, in some embodiments, the optical system 100 satisfies the conditional formula: f*43 / (ImgH*FNO)<25; wherein f is the effective focal length of the optical system 100, ImgH is the diagonal length of the effective pixel area of ​​the optical system 100 on the imaging plane, and FNO is the aperture number of the optical system 100. Specifically, f*43 / ImgH / FNO can be: 20.170, 20.325, 20.784, 21.369, 21.536, 22.824, 23.001, 23.520, 23.971 or 24.204. The above conditional formula is the equivalent focal length of the optical system 100 calculated based on the full frame, and generally, the optical system 100 with an equivalent focal length greater than 50 mm has a certain telephoto performance. When the above conditional formula is met, the magnification capability of the optical system 100 is greater than twice the magnification capability of the optical system 100 with an equivalent focal length of 25 mm, and the value of ImgH is relatively large, so that the optical system 100 can adapt to a larger size and higher pixel photosensitive element, thereby improving the imaging clarity of the optical system 100. In addition, when the above conditional formula is met, the effective focal length of the optical system 100, the diagonal length of the effective pixel area on the imaging surface, and the aperture number can be reasonably configured, so that the optical system 100 has a larger magnification, so that the system can achieve a close-up shooting effect for a distant subject. In addition, compared with a general system with the same magnification, the optical system 100 has a larger aperture to improve the luminous flux of the optical system 100, so that the optical system 100 can also have excellent imaging quality in an environment with insufficient light.

[0069] In some embodiments, the optical system 100 satisfies the conditional formula: 1.9≤(|R32|+|R42|) / f≤7.2; wherein R32 is the radius of curvature of the image side surface S6 of the third lens L3 at the optical axis, and R42 is the radius of curvature of the image side surface S8 of the fourth lens L4 at the optical axis. Specifically, (|R32|+|R42|) / f may be: 1.997, 2.203, 2.869, 3.552, 4.451, 5.637, 6.114, 6.502, 6.985 or 7.108. The third lens L3 provides positive or negative refractive power to the optical system 100, and the fourth lens L4 provides positive or negative refractive power to the optical system 100. The combination of the third lens L3 and the fourth lens L4 can better correct the distortion and coma generated by the lenses on the object side of the third lens L3. When the above conditional expression is satisfied, the curvature radii of the image side surface S6 of the third lens L3 and the image side surface S8 of the fourth lens L4 at the optical axis and the effective focal length of the optical system 100 can be reasonably configured to avoid the image side surfaces of the third lens L3 and the fourth lens L4 being too curved or too flat, which would cause a large spherical aberration or vertical axis chromatic aberration in the optical system 100, thereby facilitating a reasonable distribution of primary aberrations in the lenses of the optical system 100 and reducing the tolerance sensitivity of the optical system 100.

[0070] In some embodiments, the optical system 100 satisfies the condition: 5≤(|f2|+|f3|) / R31≤22; wherein f2 is the effective focal length of the second lens L2, f3 is the effective focal length of the third lens L3, and R31 is the radius of curvature of the object side surface S5 of the third lens L3 at the optical axis. Specifically, (|f2|+|f3|) / R31 may be: 5.625, 7.103, 8.564, 10.228, 12.514, 15.745, 16.268, 18.034, 20.551, or 21.145. The second lens L2 provides negative refractive power for the optical system 100, and the third lens L3 provides positive or negative refractive power for the optical system 100. When the above conditional expression is satisfied, the second lens L2 and the third lens L3 as a whole can offset the primary aberration generated by the first lens L1; meanwhile, the effective focal lengths of the second lens L2 and the third lens L3 and the radius of curvature of the object side surface S5 of the third lens L3 at the paraxial position can be reasonably configured to avoid the second lens L2 and the third lens L3 from generating large spherical aberration and vertical axis chromatic aberration for the optical system 100, which is beneficial to the reasonable distribution of the primary aberration in each lens of the optical system 100 and reduces the tolerance sensitivity of the optical system 100.

[0071] In some embodiments, the optical system 100 satisfies the conditional formula: f / f1≤2; wherein f1 is the effective focal length of the first lens L1. Specifically, f / f1 may be: 1.869, 1.872, 1.895, 1.910, 1.934, 1.955, 1.963, 1.975, 1.982 or 1.998. When the above conditional formula is satisfied, the effective focal length of the first lens L1 and the effective focal length of the optical system 100 can be reasonably configured, so that the refractive power of the first lens L1 in the optical system 100 is moderate, so as to effectively reduce the generation of chromatic aberration and spherical aberration, improve the imaging quality of the optical system 100, and help reduce the sensitivity of the optical system 100. At the same time, while maintaining the miniaturized design of the optical system 100, the optical system 100 can also have a telephoto characteristic.

[0072] In some embodiments, the fourth lens L4 has positive refractive power, at least one of the object-side surface S9 or the image-side surface S10 of the fifth lens L5 has an inflection point, and the optical system 100 satisfies the condition: |R41 / R51|≤1; wherein R41 is the radius of curvature of the object-side surface S9 of the fourth lens L4 at the optical axis, and R51 is the radius of curvature of the object-side surface S9 of the fifth lens L5 at the optical axis. Specifically, |R41 / R51| may be: 0.176, 0.255, 0.364, 0.482, 0.512, 0.637, 0.702, 0.854, 0.906, or 0.963. When the above conditional expression is met, the values ​​of R41 and R51 can be reasonably configured to ensure that the object-side surface S7 of the fourth lens L4 and the object-side surface S9 of the fifth lens L5 can reasonably distribute the refractive power in the vertical direction, thereby suppressing the aberration of the optical system 100 and facilitating reducing the size of the diffuse spot in the optical system 100.

[0073] In some embodiments, the optical system 100 satisfies the conditional formula: f≥7.2mm; TTL≤7mm; TTL / f≤1.0; wherein TTL is the distance from the object side surface S1 of the first lens L1 to the imaging surface of the optical system 100 on the optical axis, that is, the total length of the optical system 100. Specifically, f may be: 7.205mm. TTL may be: 6.6, 6.7, 6.8, 6.9 or 7, and the data unit is mm. TTL / f may be: 0.916, 0.925, 0.937, 0.941, 0.946, 0.950, 0.958, 0.963, 0.969 or 0.972. When the conditional formula: f≥7.2mm is satisfied, it is beneficial for the optical system 100 to cooperate with the photosensitive element and have a long focal length characteristic. Furthermore, when the above conditional expression is satisfied, in the case of TTL ≤ 7 mm, the optical system 100 can have a long focal length, which is beneficial for the installation of the optical system 100 in a miniaturized electronic device. In addition, when the above conditional expression is satisfied, it is beneficial to correct aberrations such as chromatic aberration, spherical aberration and distortion of the optical system 100, thereby improving the imaging quality of the optical system 100.

[0074] In some embodiments, the optical system 100 satisfies the condition: 4≤(|f1|+|f2|+|f3|) / f≤27; wherein 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. Specifically, (|f1|+|f2|+|f3|) / f may be: 4.460, 7.564, 9.332, 11.258, 14.751, 19.325, 20.834, 22.364, 24.683, or 26.836. The first lens L1, the second lens L2 and the third lens L3 form a front lens group of the optical system 100. When the above conditional expression is satisfied, the effective focal lengths of the first lens L1, the second lens L2, the third lens L3 and the optical system 100 can be reasonably configured to avoid large aberrations in the front lens group, thereby improving the imaging quality of the optical system 100. At the same time, it is also beneficial to shorten the size of the front lens group in the optical axis direction, thereby shortening the total length of the optical system 100 and achieving a miniaturized design.

[0075] In some embodiments, the optical system 100 satisfies the conditional formula: 6≤TTL / (CT23+CT45)≤8.3; wherein TTL is the distance on the optical axis from the object side surface S1 of the first lens L1 to the imaging surface of the optical system 100, CT23 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, and CT45 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. Specifically, TTL / (CT23+CT45) may be: 6.190, 6.325, 6.714, 6.955, 7.210, 7.523, 7.687, 7.924, 8.034, or 8.252. When the above conditional expression is satisfied, the arrangement between the third lens L3 and the fourth lens L4 can be made more compact, so that the third lens L3 and the fourth lens L4 become transition parts of light deflection in the optical system 100, even if the refractive power of the third lens L3 and the fourth lens L4 in the optical system 100 is small, thereby reducing the sensitivity of the optical system 100 to the distance between the third lens L3 and the fourth lens L4.

[0076] In some embodiments, the optical system 100 satisfies the conditional formula: -0.5≤|R41| / f4≤0.2; wherein R41 is the radius of curvature of the object side surface S7 of the fourth lens L4 at the optical axis, and f4 is the effective focal length of the fourth lens L4. Specifically, |R41| / f4 can be: -0.195, -0.162, -0.124, -0.065, -0.013, 0.025, 0.078, 0.135, 0.184 or 0.205. When the above conditional formula is satisfied, the radius of curvature of the object side surface S7 of the fourth lens L4 at the optical axis and the effective focal length of the fourth lens L4 can be reasonably configured, so that the surface complexity of the fourth lens L4 is reduced, which is beneficial to suppress the distortion of the optical system 100 and the generation of field curvature in the meridian direction, so as to improve the imaging quality of the optical system 100, and also beneficial to reduce the difficulty of molding the fourth lens L4.

[0077] Based on the description of the above embodiments, more specific embodiments and drawings are presented below for detailed description.

[0078] First embodiment

[0079] See also Figure 1 and Figure 2 , Figure 1is a schematic diagram of the optical system 100 in the first embodiment. The optical system 100 includes, 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 positive refractive power, and a seventh lens L7 with negative refractive power. Figure 2 From left to right are graphs of spherical aberration, astigmatism and distortion of the optical system 100 in the first embodiment, wherein the reference wavelength of the astigmatism graph and the distortion graph is 587.5618 nm, which is the same for other embodiments.

[0080] The object-side surface S1 of the first lens L1 is convex at the paraxial position, and the image-side surface S2 is convex at the paraxial position;

[0081] The object-side surface S3 of the second lens L2 is convex at the paraxial position, and the image-side surface S4 is concave at the paraxial position;

[0082] The object-side surface S5 of the third lens L3 is convex at the paraxial position, and the image-side surface S6 is concave at the paraxial position;

[0083] The object-side surface S7 of the fourth lens L4 is concave at the paraxial position, and the image-side surface S8 is convex at the paraxial position;

[0084] The object-side surface S9 of the fifth lens L5 is concave at the paraxial position, and the image-side surface S10 is convex at the paraxial position;

[0085] The object-side surface S11 of the sixth lens L6 is concave at the paraxial position, and the image-side surface S12 is convex at the paraxial position;

[0086] The object-side surface S13 of the seventh lens L7 is concave at the paraxial position, and the image-side surface S14 is concave at the paraxial position.

[0087] The object-side surfaces and image-side surfaces of the first lens L1 , the second lens L2 , the third lens L3 , the fourth lens L4 , the fifth lens L5 , the sixth lens L6 and the seventh lens L7 are all aspherical surfaces.

[0088] It should be noted that, in the present application, when a surface of a lens is described as being convex at the paraxial position (the central area of ​​the side), it can be understood that the area of ​​the surface of the lens near the optical axis is convex.

[0089] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are all made of plastic.

[0090] Furthermore, the optical system 100 satisfies the conditional formula: f*43 / (ImgH*FNO)=20.170; wherein f is the effective focal length of the optical system 100, ImgH is the diagonal length of the effective pixel area of ​​the optical system 100 on the imaging plane, and FNO is the aperture number of the optical system 100. The above conditional formula is the equivalent focal length of the optical system 100 calculated based on the full frame, and generally, the optical system 100 with an equivalent focal length greater than 25mm has a certain telephoto performance. When the above conditional formula is met, the magnification capability of the optical system 100 is greater than twice the magnification capability of the optical system 100 with an equivalent focal length of 50mm, and the value of ImgH is large, so that the optical system 100 can adapt to larger size and higher pixel photosensitive elements, thereby improving the imaging clarity of the optical system 100. Furthermore, when the above-mentioned conditional expressions are satisfied, the effective focal length of the optical system 100, the diagonal length of the effective pixel area on the imaging plane, and the aperture number can be reasonably configured, so that the optical system 100 has a larger magnification, thereby enabling the system to achieve a close-up shooting effect for a distant subject. In addition, compared with a general system with the same magnification, the optical system 100 has a larger aperture to improve the luminous flux of the optical system 100, so that the optical system 100 can have excellent imaging quality even in an environment with insufficient light.

[0091] The optical system 100 satisfies the conditional formula: (|R32|+|R42|) / f=2.879; wherein R32 is the radius of curvature of the image side surface S6 of the third lens L3 at the optical axis, and R42 is the radius of curvature of the image side surface S8 of the fourth lens L4 at the optical axis. The third lens L3 provides positive or negative refractive power to the optical system 100, and the fourth lens L4 provides positive or negative refractive power to the optical system 100. The combination of the third lens L3 and the fourth lens L4 can better correct the distortion and coma generated by the lenses on the object side of the third lens L3. When the above conditional expression is satisfied, the curvature radii of the image side surface S6 of the third lens L3 and the image side surface S8 of the fourth lens L4 at the optical axis and the effective focal length of the optical system 100 can be reasonably configured to avoid the image side surfaces of the third lens L3 and the fourth lens L4 being too curved or too flat, which would cause a large spherical aberration or vertical axis chromatic aberration in the optical system 100, thereby facilitating a reasonable distribution of primary aberrations in the lenses of the optical system 100 and reducing the tolerance sensitivity of the optical system 100.

[0092] The optical system 100 satisfies the conditional expression: (|f2|+|f3|) / R31=16.539; wherein f2 is the effective focal length of the second lens L2, f3 is the effective focal length of the third lens L3, and R31 is the radius of curvature of the object side surface S5 of the third lens L3 at the optical axis. The second lens L2 provides negative refractive power to the optical system 100, and the third lens L3 provides positive or negative refractive power to the optical system 100. When the above conditional expression is satisfied, the second lens L2 and the third lens L3 as a whole can offset the primary aberration generated by the first lens L1; at the same time, the effective focal lengths of the second lens L2 and the third lens L3 and the radius of curvature of the object side surface S5 of the third lens L3 at the paraxial position can be reasonably configured to avoid the second lens L2 and the third lens L3 from generating large spherical aberration and vertical axis chromatic aberration to the optical system 100, thereby facilitating the reasonable distribution of primary aberrations in each lens of the optical system 100 and reducing the tolerance sensitivity of the optical system 100.

[0093] The optical system 100 satisfies the conditional formula: f / f1=1.960; wherein f1 is the effective focal length of the first lens L1. When the above conditional formula is satisfied, the effective focal length of the first lens L1 and the effective focal length of the optical system 100 can be reasonably configured, so that the refractive power of the first lens L1 in the optical system 100 is moderate, so as to effectively reduce the generation of chromatic aberration and spherical aberration, improve the imaging quality of the optical system 100, and help reduce the sensitivity of the optical system 100. At the same time, while maintaining the miniaturized design of the optical system 100, the optical system 100 can also have a telephoto characteristic.

[0094] The optical system 100 satisfies the conditional formula: |R41 / R51|=0.176; wherein R41 is the radius of curvature of the object-side surface S9 of the fourth lens L4 at the optical axis, and R51 is the radius of curvature of the object-side surface S9 of the fifth lens L5 at the optical axis. When the above conditional formula is satisfied, the values ​​of R41 and R51 can be reasonably configured to ensure that the object-side surface S7 of the fourth lens L4 and the object-side surface S9 of the fifth lens L5 can reasonably distribute the refractive power in the vertical direction, thereby suppressing the aberration of the optical system 100 and facilitating reducing the size of the diffuse spot in the optical system 100.

[0095] The optical system 100 satisfies the conditional formula: f=7.205mm; TTL=7mm; TTL / f=0.972; wherein TTL is the distance from the object side surface S1 of the first lens L1 to the imaging surface of the optical system 100 on the optical axis, that is, the total system length of the optical system 100. When the conditional formula: f≥7.2mm is satisfied, it is beneficial for the optical system 100 to cooperate with the photosensitive element and have a long focal length characteristic. Moreover, when the above conditional formula is satisfied, when TTL≤7mm, the optical system 100 can have a long focal length, which is beneficial for the installation of the optical system 100 in a miniaturized electronic device. In addition, when the above conditional formula is satisfied, it is beneficial to correct aberrations such as chromatic aberration, spherical aberration and distortion of the optical system 100, thereby improving the imaging quality of the optical system 100.

[0096] The optical system 100 satisfies the conditional expression: (|f1|+|f2|+|f3|) / f=17.499; wherein 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. The first lens L1, the second lens L2, and the third lens L3 form a front lens group of the optical system 100. When the above conditional expression is satisfied, the effective focal lengths of the first lens L1, the second lens L2, the third lens L3, and the optical system 100 can be reasonably configured to avoid large aberrations in the front lens group, thereby improving the imaging quality of the optical system 100, and at the same time, it is also beneficial to shorten the size of the front lens group in the optical axis direction, thereby shortening the total length of the optical system 100 and realizing a miniaturized design.

[0097] The optical system 100 satisfies the conditional expression: TTL / (CT23+CT45)=8.252; wherein TTL is the distance on the optical axis from the object side surface S1 of the first lens L1 to the imaging surface of the optical system 100, CT23 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, and CT45 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. When the above conditional expression is satisfied, the arrangement between the third lens L3 and the fourth lens L4 can be made more compact, thereby making the third lens L3 and the fourth lens L4 become the transition part of the light deflection in the optical system 100, even if the refractive power of the third lens L3 and the fourth lens L4 in the optical system 100 is small, thereby reducing the sensitivity of the optical system 100 to the distance between the third lens L3 and the fourth lens L4.

[0098] The optical system 100 satisfies the conditional formula: |R41| / f4=-0.142; wherein R41 is the radius of curvature of the object-side surface S7 of the fourth lens L4 at the optical axis, and f4 is the effective focal length of the fourth lens L4. When the above conditional formula is satisfied, the radius of curvature of the object-side surface S7 of the fourth lens L4 at the optical axis and the effective focal length of the fourth lens L4 can be reasonably configured, so that the surface complexity of the fourth lens L4 is reduced, which is beneficial to suppress the distortion of the optical system 100 and the generation of field curvature in the meridional direction and the T direction, so as to improve the imaging quality of the optical system 100, and also beneficial to reduce the difficulty of molding the fourth lens L4.

[0099] In addition, various parameters of the optical system 100 are given in Table 1. Among them, the image plane S17 in Table 1 can be understood as the imaging plane of the optical system 100. The elements from the object plane (not shown) to the image plane S17 are arranged in the order of the elements from top to bottom in Table 1. The Y radius in Table 1 is the radius of curvature of the object side or image side of the corresponding surface number at the optical axis. Surface number 1 and surface number 2 are the object side surface S1 and image side surface S2 of the first lens L1, respectively, 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 first value in the "Thickness" parameter column of the first lens L1 is the thickness of the lens on the optical axis, and the second value is the distance from the image side surface of the lens to the object side surface of the next lens in the image side direction on the optical axis.

[0100] It should be noted that, in this embodiment and the following embodiments, the optical system 100 may not be provided with the infrared filter L8, but in this case the distance from the image side surface S14 to the image plane S17 of the seventh lens L7 remains unchanged.

[0101] In the first embodiment, the total effective focal length f of the optical system 100 is 7.205 mm, the aperture number FNO is 2.4, the maximum field of view FOV is 46.85°, and the total length TTL of the system is 7 mm.

[0102] The focal length, refractive index and Abbe number of each lens are values ​​at d-line (587.56 nm), which is the same for other embodiments.

[0103] Table 1

[0104]

[0105]

[0106] Furthermore, the aspheric coefficients of the image side or object side of each lens of the optical system 100 are given in Table 2. Among them, the surface numbers from 1 to 14 represent the image side or object side S1 to S14 respectively. And K-A20 from top to bottom represent the types of aspheric coefficients respectively, among which K represents the cone coefficient, A4 represents the fourth-order aspheric coefficient, A6 represents the sixth-order aspheric coefficient, A8 represents the eighth-order aspheric coefficient, and so on. In addition, the formula of the aspheric coefficient is as follows:

[0107]

[0108] Among them, 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 vertex, k is the cone coefficient, and Ai is the coefficient corresponding to the i-th high-order term in the aspherical surface shape formula.

[0109] Table 2

[0110]

[0111]

[0112] Second embodiment

[0113] See also Figure 3 and Figure 4 , Figure 3 is a schematic diagram of the optical system 100 in the second embodiment. The optical system 100 includes, 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 negative refractive power, a sixth lens L6 with positive refractive power, and a seventh lens L7 with negative refractive power. Figure 4 From left to right are graphs of spherical aberration, astigmatism and distortion of the optical system 100 in the second embodiment.

[0114] The object-side surface S1 of the first lens L1 is convex at the paraxial position, and the image-side surface S2 is convex at the paraxial position;

[0115] The object-side surface S3 of the second lens L2 is convex at the paraxial position, and the image-side surface S4 is concave at the paraxial position;

[0116] The object-side surface S5 of the third lens L3 is convex at the paraxial position, and the image-side surface S6 is concave at the paraxial position;

[0117] The object-side surface S7 of the fourth lens L4 is concave at the paraxial position, and the image-side surface S8 is convex at the paraxial position;

[0118] The object-side surface S9 of the fifth lens L5 is concave at the paraxial position, and the image-side surface S10 is convex at the paraxial position;

[0119] The object-side surface S11 of the sixth lens L6 is concave at the paraxial position, and the image-side surface S12 is convex at the paraxial position;

[0120] The object-side surface S13 of the seventh lens L7 is concave at the paraxial position, and the image-side surface S14 is convex at the paraxial position.

[0121] The object-side surfaces and image-side surfaces of the first lens L1 , the second lens L2 , the third lens L3 , the fourth lens L4 , the fifth lens L5 , the sixth lens L6 and the seventh lens L7 are all aspherical surfaces.

[0122] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are all made of plastic.

[0123] In addition, various parameters of the optical system 100 are given in Table 3, and the definition of each parameter can be obtained from the first embodiment, which will not be repeated here.

[0124] Table 3

[0125]

[0126]

[0127] Furthermore, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are given in Table 4, and the definition of each parameter therein can be obtained from the first embodiment, which will not be elaborated here.

[0128] Table 4

[0129]

[0130]

[0131] Furthermore, based on the above-mentioned parameter information, the following data can be derived:

[0132] f*43 / ImgH / FNO 21.047 TTL / f 0.916 (|R32|+|R42|) / f 2.811 (|f1|+|f2|+|f3|) / f 26.836 (|f2|+|f3|) / R31 21.145 TTL / (CT23+CT45) 8.166 f / f1 1.967 |R41| / f4 -0.046 |R41 / R51| 0.214

[0133] Third embodiment

[0134] See also Figure 5 and Figure 6 , Figure 5 is a schematic diagram of the optical system 100 in the third embodiment. The optical system 100 includes, 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 negative refractive power. Figure 6 From left to right are graphs of spherical aberration, astigmatism and distortion of the optical system 100 in the third embodiment.

[0135] The object-side surface S1 of the first lens L1 is convex at the paraxial position, and the image-side surface S2 is concave at the paraxial position;

[0136] The object-side surface S3 of the second lens L2 is convex at the paraxial position, and the image-side surface S4 is concave at the paraxial position;

[0137] The object-side surface S5 of the third lens L3 is convex at the paraxial position, and the image-side surface S6 is concave at the paraxial position;

[0138] The object-side surface S7 of the fourth lens L4 is concave at the paraxial position, and the image-side surface S8 is convex at the paraxial position;

[0139] The object-side surface S9 of the fifth lens L5 is convex at the paraxial position, and the image-side surface S10 is concave at the paraxial position;

[0140] The object-side surface S11 of the sixth lens L6 is concave at the paraxial position, and the image-side surface S12 is convex at the paraxial position;

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

[0142] The object-side surfaces and image-side surfaces of the first lens L1 , the second lens L2 , the third lens L3 , the fourth lens L4 , the fifth lens L5 , the sixth lens L6 and the seventh lens L7 are all aspherical surfaces.

[0143] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are all made of plastic.

[0144] In addition, various parameters of the optical system 100 are given in Table 5, and the definition of each parameter can be obtained from the first embodiment, which will not be repeated here.

[0145] Table 5

[0146]

[0147]

[0148] Furthermore, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are given in Table 6, and the definition of each parameter therein can be obtained from the first embodiment, which will not be repeated here.

[0149] Table 6

[0150]

[0151]

[0152] Furthermore, based on the above-mentioned parameter information, the following data can be derived:

[0153] f*43 / ImgH / FNO 22.004 TTL / f 0.916 (|R32|+|R42|) / f 2.192 (|f1|+|f2|+|f3|) / f 14.404 (|f2|+|f3|) / R31 14.458 TTL / (CT23+CT45) 6.862 f / f1 1.998 |R41| / f4 -0.130 |R41 / R51| 0.534

[0154] Fourth embodiment

[0155] See also Figure 7 and Figure 8 , Figure 7 is a schematic diagram of the optical system 100 in the fourth embodiment. The optical system 100 includes, 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 8 From left to right are graphs of spherical aberration, astigmatism and distortion of the optical system 100 in the fourth embodiment.

[0156] The object-side surface S1 of the first lens L1 is convex at the paraxial position, and the image-side surface S2 is convex at the paraxial position;

[0157] The object-side surface S3 of the second lens L2 is convex at the paraxial position, and the image-side surface S4 is concave at the paraxial position;

[0158] The object-side surface S5 of the third lens L3 is convex at the paraxial position, and the image-side surface S6 is concave at the paraxial position;

[0159] The object-side surface S7 of the fourth lens L4 is concave at the paraxial position, and the image-side surface S8 is convex at the paraxial position;

[0160] The object-side surface S9 of the fifth lens L5 is convex at the paraxial position, and the image-side surface S10 is convex at the paraxial position;

[0161] The object-side surface S11 of the sixth lens L6 is convex at the paraxial position, and the image-side surface S12 is concave at the paraxial position;

[0162] The object-side surface S13 of the seventh lens L7 is concave at the paraxial position, and the image-side surface S14 is convex at the paraxial position.

[0163] The object-side surfaces and image-side surfaces of the first lens L1 , the second lens L2 , the third lens L3 , the fourth lens L4 , the fifth lens L5 , the sixth lens L6 and the seventh lens L7 are all aspherical surfaces.

[0164] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are all made of plastic.

[0165] In addition, various parameters of the optical system 100 are given in Table 7, and the definition of each parameter can be obtained from the first embodiment, which will not be repeated here.

[0166] Table 7

[0167]

[0168]

[0169] Furthermore, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are given in Table 8, and the definition of each parameter therein can be obtained from the first embodiment, which will not be repeated here.

[0170] Table 8

[0171]

[0172]

[0173] Furthermore, based on the above-mentioned parameter information, the following data can be derived:

[0174] f*43 / ImgH / FNO 23.052 TTL / f 0.947 (|R32|+|R42|) / f 1.997 (|f1|+|f2|+|f3|) / f 4.644 (|f2|+|f3|) / R31 9.293 TTL / (CT23+CT45) 6.742 f / f1 1.957 |R41| / f4 -0.195 |R41 / R51| 0.346

[0175] Fifth embodiment

[0176] See also Fig. 9 and Fig.10 , Fig. 9 is a schematic diagram of the optical system 100 in the fifth embodiment. The optical system 100 includes, 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 positive refractive power, a fifth lens L5 with negative refractive power, a sixth lens L6 with positive refractive power, and a seventh lens L7 with negative refractive power. Fig.10 From left to right are graphs of spherical aberration, astigmatism and distortion of the optical system 100 in the fifth embodiment.

[0177] The object-side surface S1 of the first lens L1 is convex at the paraxial position, and the image-side surface S2 is convex at the paraxial position;

[0178] The object-side surface S3 of the second lens L2 is convex at the paraxial position, and the image-side surface S4 is concave at the paraxial position;

[0179] The object-side surface S5 of the third lens L3 is concave at the paraxial position, and the image-side surface S6 is convex at the paraxial position;

[0180] The object-side surface S7 of the fourth lens L4 is convex at the paraxial position, and the image-side surface S8 is concave at the paraxial position;

[0181] The object-side surface S9 of the fifth lens L5 is convex at the paraxial position, and the image-side surface S10 is concave at the paraxial position;

[0182] The object-side surface S11 of the sixth lens L6 is convex at the paraxial position, and the image-side surface S12 is convex at the paraxial position;

[0183] The object-side surface S13 of the seventh lens L7 is concave at the paraxial position, and the image-side surface S14 is concave at the paraxial position.

[0184] The object-side surfaces and image-side surfaces of the first lens L1 , the second lens L2 , the third lens L3 , the fourth lens L4 , the fifth lens L5 , the sixth lens L6 and the seventh lens L7 are all aspherical surfaces.

[0185] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are all made of plastic.

[0186] In addition, various parameters of the optical system 100 are given in Table 9, and the definition of each parameter can be obtained from the first embodiment, which will not be repeated here.

[0187] Table 9

[0188]

[0189]

[0190] Furthermore, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are given in Table 10, and the definition of each parameter therein can be obtained from the first embodiment, which will not be repeated here.

[0191] Table 10

[0192]

[0193] Furthermore, based on the above-mentioned parameter information, the following data can be derived:

[0194] f*43 / ImgH / FNO 24.204 TTL / f 0.958 (|R32|+|R42|) / f 7.108 (|f1|+|f2|+|f3|) / f 4.460 (|f2|+|f3|) / R31 5.625 TTL / (CT23+CT45) 6.190 f / f1 1.869 |R41| / f4 0.205 |R41 / R51| 0.963

[0195] See also Fig.11In some embodiments, the optical system 100 can be assembled with the photosensitive element 210 to form the imaging module 200. At this time, the photosensitive surface of the photosensitive element 210 can be regarded as the image surface S17 of the optical system 100. The imaging module 200 can also be provided with an infrared filter L8, and the infrared filter L8 is arranged between the image side surface S14 of the seventh lens L7 and the image surface S17. Specifically, the photosensitive element 210 can be a charge coupled device (CCD) or a complementary metal oxide semiconductor device (CMOS Sensor). The use of the above optical system 100 in the imaging module 200 can enhance the magnification ability of the imaging module 200, so that the optical system 100 can adapt to a larger size and higher pixel photosensitive element, thereby improving the imaging quality of the optical system 100. In addition, the imaging module 200 can have excellent imaging quality when imaging a distant object, and can also improve the imaging quality of the imaging module 200 in a dark environment.

[0196] See also Fig.11 and Fig.12 In some embodiments, the imaging module 200 can be used in an electronic device 300, and the electronic device includes a housing 310, and the imaging module 200 is disposed in the housing 310. Specifically, the electronic device 300 can be, but is not limited to, a portable phone, a video phone, a smart phone, an e-book reader, a driving recorder, or other vehicle-mounted imaging equipment or a wearable device such as a smart watch. By using the imaging module 200 in the electronic device 300, the imaging quality of the electronic device 300 can be improved by enhancing the magnification capability of the optical system 100. In addition, it is beneficial for the electronic device 300 to have excellent imaging quality when imaging a distant object, and it can also improve the imaging quality of the electronic device 300 in a dark environment.

[0197] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0198] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An optical system, characterized in that: There are seven lenses with refractive power, including: A first lens having positive refractive power, wherein the object side surface of the first lens is convex at the paraxial position; a second lens having negative refractive power, wherein the object side surface of the second lens is convex at the paraxial position, and the image side surface of the second lens is concave at the paraxial position; a third lens having refractive power; a fourth lens having a refractive power; a fifth lens having refractive power; a sixth lens having a refractive power; a seventh lens having refractive power, wherein the object side surface of the seventh lens is concave at the paraxial position; And the optical system satisfies the following conditional formula: 20.170≤f*43 / (ImgH*FNO)<25; TTL / f≤1.0; Wherein, f is the effective focal length of the optical system, ImgH is the diagonal length of the effective pixel area of ​​the optical system on the imaging plane, FNO is the aperture number of the optical system, and TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis.

2. The optical system according to claim 1, characterized in that The following conditions are met: 1.9≤(|R32|+|R42|) / f≤7.2; Wherein, R32 is the curvature radius of the image side surface of the third lens at the optical axis, and R42 is the curvature radius of the image side surface of the fourth lens at the optical axis.

3. The optical system according to claim 1, characterized in that The following conditions are met: 5≤(|f2|+|f3|) / R31≤22; Wherein, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, and R31 is the radius of curvature of the object side of the third lens at the optical axis.

4. The optical system according to claim 1, characterized in that The following conditions are met: 1.869≤f / f1≤2; Wherein, f1 is the effective focal length of the first lens.

5. The optical system according to claim 1, characterized in that The fourth lens has positive refractive power, at least one of the object side surface or the image side surface of the fifth lens has an inflection point, and the optical system satisfies the following conditional formula: |R41 / R51|≤1; Wherein, R41 is the curvature radius of the object side of the fourth lens at the optical axis, and R51 is the curvature radius of the object side of the fifth lens at the optical axis.

6. The optical system according to claim 1, characterized in that The following conditions are met: f≥7.2mm; TTL≤7mm; 0.916≤TTL / f≤1.

0.

7. The optical system according to claim 1, characterized in that The following conditions are met: 4≤(|f1|+|f2|+|f3|) / f≤27; Wherein, 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.

8. The optical system according to claim 1, characterized in that The following conditions are met: 6≤TTL / (CT23+CT45)≤8.3; Wherein, 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, CT23 is the distance from the image side surface of the second lens to the object side surface of the third lens on the optical axis, and CT45 is the distance from the image side surface of the fourth lens to the object side surface of the fifth lens on the optical axis.

9. The optical system according to claim 1, characterized in that The following conditions are met: -0.5≤|R41| / f4≤0.2; Wherein, R41 is the curvature radius of the object side of the fourth lens at the optical axis, and f4 is the effective focal length of the fourth lens.

10. An imaging module, characterized in that: The optical system comprises a photosensitive element and any one of claims 1 to 9, wherein the photosensitive element is arranged on the image side of the optical system.

11. An electronic device, characterized in that: It comprises a shell and the imaging module according to claim 10, wherein the imaging module is arranged in the shell.

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