Optical systems, camera modules and electronic equipment

Abstract

The present invention relates to an optical system, a camera module and an electronic device. The optical system includes, from the object side to the image side, a positive first lens; a negative second lens, whose object side surface is convex at the near optical axis; a positive third lens, whose image side surface is convex at the near optical axis; a fourth lens, whose object side surface is concave at the near optical axis, and whose image side surface is convex at the near optical axis; a negative fifth lens, whose object side surface is concave at the near optical axis, and whose image side surface is convex at the near optical axis; a positive sixth lens, whose object side surface is convex at the near optical axis, and whose image side surface is convex at the near maximum effective aperture; a negative seventh lens, whose object side surface is convex at the near optical axis; the optical system satisfies the relationship: 1.2<f234 / f1<2.5; f234 is the combined focal length of the second, third and fourth lenses, and f1 is the effective focal length of the first lens. The above optical system can be miniaturized and has good imaging quality.

Description

Technical Field

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

[0002] As the market's pursuit of miniaturization of electronic devices increases, how to reduce the size of various modules in the device to reduce the space they occupy in the device has become one of the key concerns of the industry when designing miniaturized devices.

[0003] However, for general camera modules, although the image quality can be improved by increasing the number of lenses, it is often difficult to reduce the axial size of the module and achieve miniaturization. If the module size is compressed by directly compressing the lens spacing, reducing the number of lenses, etc., it will cause serious deterioration in image quality. Summary of the invention

[0004] Based on this, it is necessary to provide an optical system, a camera module and an electronic device to address the problem of how to balance miniaturization and good imaging quality.

[0005] An optical system, comprising, in order from the object side to the image side along the optical axis:

[0006] a first lens having positive refractive power;

[0007] a second lens having negative refractive power, wherein the object side surface of the second lens is convex at a position close to the optical axis;

[0008] a third lens element having positive refractive power, wherein the image side surface of the third lens element is convex at the near optical axis;

[0009] a fourth lens having a refractive power, wherein the object side surface of the fourth lens is concave at the near optical axis, and the image side surface of the fourth lens is convex at the near optical axis;

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

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

[0012] a seventh lens element having negative refractive power, wherein the object side surface of the seventh lens element is convex at a position close to the optical axis;

[0013] The optical system satisfies the relationship condition:

[0014] 1.2<f234 / f1<2.5;

[0015] f234 is the combined focal length of the second lens, the third lens and the fourth lens, and f1 is the effective focal length of the first lens.

[0016] The optical system with a seven-piece structure can well correct aberrations by satisfying the surface shape and refractive power configuration of the corresponding lenses, so as to improve the imaging quality of the optical system, and is also conducive to compressing the size of the optical system in the direction of the optical axis. The configuration of multiple lenses in a positive and negative refractive power cycle can facilitate the correction of aberrations generated by each lens in sequence and smoothly, and can better avoid the problem of undercorrection or overcorrection. In particular, by making the object side of the sixth lens meet the above-mentioned surface shape setting, the deflection of light in the edge field of view can be effectively suppressed, that is, the incident angle of light in the edge field of view on the imaging surface of the optical system is reduced, which is conducive to alleviating the dark corner problem of edge imaging under a large field of view; at the same time, it can also effectively improve spherical aberration, and well correct off-axis coma and astigmatism.

[0017] When the above relationship conditions are further satisfied, the combined focal length of the second lens, the third lens and the fourth lens can be reasonably constrained with the effective focal length of the first lens. On the one hand, the optical system can enhance its ability to converge incident light, which is beneficial to shortening the total length of the system, and can also obtain a larger field of view. On the other hand, the positive and negative lens combination can offset the aberration defects such as spherical aberration generated by each other. The positive refractive power provided by the first lens and the negative refractive power provided by the second lens can also promote the balance of the system's spherical aberration and achieve good imaging quality. When f234 / f1≥2.5, the equivalent positive refractive power of the front lens group formed by the first lens to the fourth lens is too strong, resulting in insufficient aberration correction ability of the rear lens group formed by the fifth lens to the seventh lens, resulting in high-order aberrations, affecting the imaging quality of the optical system. When f234 / f≤1.2, the equivalent positive refractive power of the front lens group is insufficient, making it difficult to effectively shorten the total length of the optical system, which is not conducive to the miniaturization design of the optical system.

[0018] In some embodiments, the optical system satisfies the relationship:

[0019] -5.0<(R12+R13) / (R12-R13)<0;

[0020] R12 is the radius of curvature of the object side of the sixth lens at the optical axis, and R13 is the radius of curvature of the image side of the sixth lens at the optical axis. When the above-mentioned surface configuration and relationship conditions are met, the radius of curvature of the object side and image side of the sixth lens at the optical axis can be appropriately configured, so that the surface shapes of the object side and image side of the sixth lens can be well controlled to effectively reduce the incident angle of light in the edge field of view on the imaging surface, and further alleviate the problem of dark corners easily generated around the image under large field of view conditions.

[0021] In some embodiments, the optical system satisfies the relationship:

[0022] 0.4<T12 / CT1<0.65;

[0023] T12 is the distance from the image side of the first lens to the object side of the second lens on the optical axis, and CT1 is the thickness of the first lens on the optical axis. When the above relationship is satisfied, the thickness of the first lens can be reasonably controlled, and there is a suitable assembly space between the first lens and the second lens, which is beneficial to the manufacture and assembly of the first lens, and is beneficial to maintaining the miniaturization characteristics of the first lens, thereby facilitating the miniaturization of the optical system.

[0024] In some embodiments, the optical system satisfies the relationship:

[0025] 0.58<(T45+CT5) / (CT3+CT4)<0.95;

[0026] T45 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, CT3 is the thickness of the third lens on the optical axis, CT4 is the thickness of the fourth lens on the optical axis, and CT5 is the thickness of the fifth lens on the optical axis. When the above relationship is satisfied, the configuration of the lens group in the optical system can be made more compact, and the axial dimension of the optical system can be effectively shortened, thereby maintaining the miniaturized design of the optical system.

[0027] In some embodiments, the optical system satisfies the relationship:

[0028] 1.3<TTL / ImgH<1.5;

[0029] TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis, and ImgH is half of the image height corresponding to the maximum field angle of the optical system. When the above conditions are met, the optical system with the above seven-piece design will have a large image plane characteristic, so that it can match a high-pixel image sensor, and thus can meet high-quality imaging effects; it can also effectively reduce the total length of the optical system, thereby achieving a small-size design of the optical system in the direction of the optical axis. When it is higher than the upper limit of the relationship, it is difficult for the optical system to have a large image plane characteristic, and the total length of the optical system is also difficult to be effectively compressed, which is not conducive to miniaturization design. When it is lower than the lower limit of the relationship, the image height corresponding to the maximum field angle of the optical system is too large, that is, the image plane size is too large, which easily leads to the vignetting phenomenon around the image being too obvious.

[0030] In some embodiments, the optical system satisfies the relationship:

[0031] -0.7<f / f7<-0.3;

[0032] f is the effective focal length of the optical system, and f7 is the effective focal length of the seventh lens. When the above relationship is satisfied, it helps to bring the principal point of the optical system close to the imaging plane. At this time, the refractive power of the seventh lens increases, resulting in the curvature of the seventh lens surface, which is beneficial to shorten the back focal length of the optical system to maintain miniaturization. At the same time, the refractive power of the seventh lens is appropriate, which can reduce the design complexity of each lens on the object side, and further reduce the tolerance sensitivity of the lens group in the optical system. When it is lower than the lower limit of the relationship, the negative refractive power of the seventh lens is too strong, making it difficult to shorten the length of the optical system. When it is higher than the upper limit of the relationship, the refractive power of the seventh lens is insufficient, making it difficult to reasonably correct the aberrations generated by the object side lens.

[0033] In some embodiments, the optical system satisfies the relationship:

[0034] 0.8<f3 / f1<1.8;

[0035] f1 is the effective focal length of the first lens, and f3 is the effective focal length of the third lens. Both the first lens and the third lens provide positive refractive power for the system, and when the above relationship is satisfied, the effective focal lengths of the first lens and the third lens can be reasonably controlled, thereby balancing the positive refractive power of the first lens, so as to avoid excessive increase in spherical aberration due to excessive concentration of refractive power on the first lens, thereby reducing the imaging quality of the optical system.

[0036] In some embodiments, the optical system satisfies the relationship:

[0037] 7.0<CT6 / |SAG61|<88.0;

[0038] CT6 is the thickness of the sixth lens on the optical axis, and SAG61 is the sagittal height of the object side of the sixth lens at the maximum effective aperture. When the above relationship is satisfied, the central thickness of the sixth lens and the edge sagittal height of the object side can be mutually constrained, so as to reduce the surface complexity of the object side, thereby facilitating the manufacture and molding of the sixth lens, and reducing the defects of poor lens molding; it can also trim the field curvature generated by each lens on the object side, so as to promote the balance of the field curvature of the optical system and improve the imaging quality of the optical system.

[0039] In some embodiments, the optical system satisfies the relationship:

[0040] 3.0<(V3+V4) / V5<6.0;

[0041] V3 is the Abbe number of the third lens under d light, V4 is the Abbe number of the fourth lens under d light, and V5 is the Abbe number of the fifth lens under d light. When the above relationship is satisfied, the degree of deflection of light passing through the third lens, the fourth lens, and the fifth lens can be controlled, which is beneficial to enhancing the lens aberration correction capability and suppressing the dispersion problem generated when light passes through these lenses, thereby balancing the chromatic aberration of the optical system.

[0042] In some embodiments, the optical system satisfies the relationship:

[0043] 0.3<R10 / R11<0.8;

[0044] R10 is the radius of curvature of the object side of the fifth lens at the optical axis, and R11 is the radius of curvature of the image side of the fifth lens at the optical axis. When the above relationship is satisfied, the relationship between the radius of curvature of the object side and the image side of the fifth lens can be reasonably constrained, so that the light deflection angle borne by the lens can be effectively distributed, and at the same time, the off-axis field of view astigmatism can be improved, making the imaging surface flatter, thereby improving the imaging quality of the optical system.

[0045] In some embodiments, the optical system satisfies the relationship:

[0046] 3.0<|f7| / R14<9.0;

[0047] f7 is the effective focal length of the seventh lens, and R14 is the curvature radius of the object side of the seventh lens at the optical axis. When the above relationship is satisfied, the relationship between the effective focal length of the seventh lens and the curvature radius of the object side at the optical axis can be reasonably configured to reduce the incident angle of light on the image sensor, so that the optical system can better match with common image sensors, and also avoid the generation of serious ghost images and stray light.

[0048] A camera module comprises an image sensor and any one of the above optical systems, wherein the image sensor is arranged on the image side of the optical system. By adopting the above optical system, the camera module can compress the axial dimension to achieve a miniaturized design, and also obtain a larger field of view. It is also conducive to balancing spherical aberration and alleviating the dark corner problem of edge imaging under a large field of view, thereby having good imaging quality.

[0049] An electronic device comprises a fixing part and the camera module, wherein the camera module is arranged on the fixing part. The electronic device can assemble the camera module in a smaller space, and because the axial dimension of the camera module can be compressed and has good imaging quality, it is also beneficial for the device to achieve a thin design while having good shooting quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1A schematic diagram of the structure of an optical system provided in the first embodiment of the present application;

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

[0052] Figure 3 A schematic diagram of the structure of an optical system provided in the second embodiment of the present application;

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

[0054] Figure 5 A schematic diagram of the structure of an optical system provided in the third embodiment of the present application;

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

[0056] Figure 7 A schematic diagram of the structure of an optical system provided in a fourth embodiment of the present application;

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

[0058] Fig. 9 A schematic diagram of the structure of an optical system provided in a fifth embodiment of the present application;

[0059] Fig.10 including a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of the optical system in the fifth embodiment;

[0060] Fig.11 A schematic diagram of the structure of an optical system provided in a sixth embodiment of the present application;

[0061] Fig.12 including a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of the optical system in the sixth embodiment;

[0062] Fig.13 A schematic diagram of a camera module provided in one embodiment of the present application;

[0063] Fig.14 A schematic diagram of the structure of an electronic device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] refer to Figure 1 , an embodiment of the present application provides an optical system 10 with a seven-piece structure, and the optical system 10 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a seventh lens L7 in sequence from the object side to the image side along the optical axis 101. The lenses in the optical system 10 are coaxially arranged, that is, the optical axes of the lenses are all located on the same straight line, which can be called the optical axis 101 of the optical system 10. The above-mentioned optical elements in the optical system 10 and the aperture not mentioned yet can be assembled with the lens barrel to form a camera lens.

[0071] 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 also 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 ease of understanding, the imaging surface S15 can be regarded as the photosensitive surface of the image sensor.

[0072] In the embodiments of the present application, the first lens L1 has positive refractive power; the second lens L2 has negative refractive power, and its object-side surface S3 is convex at the near optical axis; the third lens L3 has positive refractive power, and its image-side surface S6 is convex at the near optical axis; the fourth lens L4 has positive refractive power or negative refractive power, its object-side surface S7 is concave at the near optical axis, and its image-side surface S8 is convex at the near optical axis; the fifth lens L5 has negative refractive power, its object-side surface S9 is concave at the near optical axis, and its image-side surface S10 is convex at the near optical axis; the sixth lens L6 has positive refractive power, its object-side surface S11 is convex at the near optical axis, and is concave near the maximum effective aperture, that is, is concave near the circumference; the seventh lens L7 has negative refractive power, and its object-side surface S13 is convex at the near optical axis. It should be noted that when the embodiments of the present application describe a surface of a lens as convex near the optical axis, it can be understood that the area of ​​the surface of the lens near the optical axis 101 is convex; when describing a surface of a lens as concave near the maximum effective aperture or near the circumference, it can be understood that the area of ​​the surface near the maximum effective aperture is concave. For example, when the surface is convex near the optical axis and also convex near the circumference, the shape of the surface from the center (optical axis) to the edge direction can be purely convex; or it can first transition from a convex shape in the center to a concave shape, and then become convex when close to the maximum effective aperture. The description of the concave and convex surface type in the present application is only for the surface type of the effective light-transmitting area of ​​the corresponding lens surface.

[0073] The refractive power and surface shape of each lens distributed from the object side to the image side are reasonably matched, so that the aberration can be well corrected to improve the imaging quality of the optical system 10, and it is also beneficial to compress the size of the optical system 10 in the optical axis direction. The configuration of multiple lenses in a positive and negative refractive power cycle can facilitate the aberrations generated by each lens to be corrected in sequence and smoothly, and can better avoid the problem of undercorrection or overcorrection. In particular, by making the object side surface S11 of the sixth lens L6 meet the above-mentioned surface shape setting, the deflection of the light in the edge field of view can be effectively suppressed, that is, the incident angle of the light in the edge field of view on the imaging surface S15 of the optical system 10 is reduced, which is beneficial to alleviate the dark corner problem of edge imaging under a large field of view; at the same time, it can also effectively improve spherical aberration, and well correct off-axis coma and astigmatism.

[0074] In the embodiment of the present application, the optical system 10 also satisfies the relationship: 1.2<f234 / f1<2.5; f234 is the combined focal length of the second lens L2, the third lens L3 and the fourth lens L4, and f1 is the effective focal length of the first lens L1.

[0075] The optical system 10 with the above-mentioned seven-lens structure design, when further satisfying the above-mentioned relationship conditions, can obtain a reasonable constraint between the combined focal length of the second lens L2, the third lens L3 and the fourth lens L4 and the effective focal length of the first lens L1, which can enhance the convergence ability of the optical system 10 on the incident light, thereby facilitating the shortening of the total length of the optical system 10 and obtaining a larger field of view; on the other hand, the positive and negative lens combination can offset the aberration defects such as spherical aberration generated by each other, and the positive refractive power provided by the first lens L1 and the negative refractive power provided by the second lens L2 can also promote the balance of the spherical aberration of the optical system 10, thereby achieving good imaging quality. When f234 / f1≥2.5, the equivalent positive refractive power of the front lens group composed of the first lens L1 to the fourth lens L4 is too strong, thereby causing the rear lens group composed of the fifth lens L5 to the seventh lens L7 to have insufficient aberration correction ability, resulting in high-order aberrations, and affecting the imaging quality of the optical system 10. When f234 / f≤1.2, the equivalent positive refractive power of the front lens group is insufficient, and it is difficult to shorten the total length of the optical system 10, which is not conducive to the miniaturization design of the optical system 10. In some embodiments, the relationship satisfied by the optical system 10 can be 1.4, 1.43, 1.47, 1.55, 1.6, 1.8, 1.9, 2.05, 2.15, 2.2 or 2.25.

[0076] In addition, in some embodiments, the optical system 10 further satisfies at least one of the following relationships, and when any of the relationships is satisfied, corresponding technical effects can be achieved:

[0077] -5.0<(R12+R13) / (R12-R13)<0; R12 is the radius of curvature of the object side surface S11 of the sixth lens L6 at the optical axis, and R13 is the radius of curvature of the image side surface S12 of the sixth lens L6 at the optical axis. When the above-mentioned surface configuration and relationship conditions are met, the radii of curvature of the object side surface S11 and the image side surface S12 of the sixth lens L6 at the optical axis can be appropriately configured, so that the surface shapes of the object side surface S11 and the image side surface S12 of the sixth lens L6 can be well controlled to effectively reduce the incident angle of the light of the edge field of view on the imaging surface S15, and further alleviate the problem of dark corners easily generated around the image under large field of view conditions. In some embodiments, the relationship satisfied by the optical system 10 can be specifically -4.2, -4, -3.8, -3.5, -3, -2.5, -2, -1.5, -1.2, -1, -0.9 or -0.75.

[0078] 0.4<T12 / CT1<0.65; 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 CT1 is the thickness of the first lens L1 on the optical axis. When the above relationship is satisfied, the thickness of the first lens L1 can be reasonably controlled, and there is a suitable assembly space between the first lens L1 and the second lens L2, which is beneficial to the manufacture and assembly of the first lens L1, and is beneficial to maintaining the miniaturization characteristics of the lens, thereby facilitating the miniaturization of the optical system 10. In some embodiments, the relationship satisfied by the optical system 10 can be specifically 0.47, 0.48, 0.5, 0.52, 0.54, 0.56, 0.58, 0.6 or 0.62.

[0079] 0.58<(T45+CT5) / (CT3+CT4)<0.95; 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, CT3 is the thickness of the third lens L3 on the optical axis, CT4 is the thickness of the fourth lens L4 on the optical axis, and CT5 is the thickness of the fifth lens L5 on the optical axis. When the above relationship is satisfied, the configuration of the lens group in the optical system 10 can be more compact, and the axial dimension of the optical system 10 can be effectively shortened, thereby maintaining the miniaturized design of the optical system 10. In some embodiments, the relationship satisfied by the optical system 10 can be 0.6, 0.62, 0.65, 0.7, 0.75, 0.8, 0.83, 0.85, 0.87 or 0.89.

[0080] 1.3<TTL / ImgH<1.5; 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 ImgH is half of the image height corresponding to the maximum field angle of the optical system 10. When the image sensor is assembled, Imgh can also be understood as the distance from the center to the diagonal edge of the rectangular effective pixel area of ​​the image sensor, and the diagonal direction of the above-mentioned effective imaging area is parallel to the diagonal direction of the rectangular effective pixel area. When the above conditions are met, the optical system 10 with the above-mentioned seven-piece design will have a large image surface characteristic, so that it can match the high-pixel image sensor, and thus can meet the high-quality imaging effect; it can also effectively reduce the total length of the optical system 10, thereby realizing the small size design of the optical system 10 in the optical axis direction. When it is higher than the upper limit of the relationship, it is difficult for the optical system 10 to have a large image surface characteristic, and the total length of the system is also difficult to be effectively compressed, which is not conducive to miniaturization design. When it is lower than the lower limit of the relationship, the image height corresponding to the maximum field angle of the optical system 10 is too large, that is, the image plane size is too large, which easily leads to too obvious vignetting around the image. In some embodiments, the relationship satisfied by the optical system 10 can be 1.40, 1.41, 1.43, 1.44, 1.46 or 1.47.

[0081] -0.7<f / f7<-0.3; f is the effective focal length of the optical system 10, and f7 is the effective focal length of the seventh lens L7. When the above relationship is satisfied, it is helpful to make the principal point of the optical system 10 close to the imaging surface S15. At this time, the refractive power of the seventh lens L7 increases, resulting in the curvature of the surface of the seventh lens L7, which is conducive to shortening the back focal length of the optical system 10 to maintain miniaturization. At the same time, the refractive power strength of the seventh lens L7 is appropriate, which can reduce the design complexity of each lens on the object side, and further reduce the tolerance sensitivity of the lens group in the optical system 10. When it is lower than the lower limit of the relationship, the negative refractive power of the seventh lens L7 is too strong, and it is difficult to shorten the length of the optical system 10. When it is higher than the upper limit of the relationship, it will lead to insufficient refractive power strength of the seventh lens L7, and it is difficult to reasonably correct the aberrations generated by the object side lens. In some embodiments, the relationship satisfied by the optical system 10 may specifically be -0.6, -0.58, -0.55, -0.5, -0.46, -0.4, -0.38 or -0.36.

[0082] 0.8<f3 / f1<1.8; f1 is the effective focal length of the first lens L1, and f3 is the effective focal length of the third lens L3. The first lens L1 and the third lens L3 both provide positive refractive power for the optical system 10, and when the above relationship is satisfied, the effective focal lengths of the first lens L1 and the third lens L3 can be reasonably controlled, so that the positive refractive power of the first lens L1 can be balanced to avoid excessive increase of spherical aberration due to excessive concentration of refractive power on the first lens L1, resulting in reduced imaging quality of the optical system 10. In some embodiments, the relationship satisfied by the optical system 10 can be 0.93, 0.95, 0.97, 1, 1.12, 1.2, 1.35, 1.44, 1.53, 1.6, 1.63 or 1.66.

[0083] 7.0<CT6 / |SAG61|<88.0; CT6 is the thickness of the sixth lens L6 on the optical axis, and SAG61 is the sag height of the object side surface S11 of the sixth lens L6 at the maximum effective aperture. When the above relationship is satisfied, the central thickness of the sixth lens L6 and the edge sag height of the object side surface S11 can be mutually constrained, so as to reduce the surface complexity of the object side surface S11, thereby facilitating the manufacture and molding of the sixth lens L6, and reducing the defects of poor molding of the lens; the field curvature generated by each lens on the object side can also be trimmed to promote the balance of the field curvature of the system and improve the imaging quality of the optical system 10. It should be noted that the sag height of the lens surface at the maximum effective aperture is the distance from the intersection of the surface and the optical axis to the maximum effective aperture in the direction parallel to the optical axis 101. In some embodiments, the relationship satisfied by the optical system 10 may specifically be 7.8, 8, 8.5, 8.74, 9, 10.4, 12.6, 13.5, 14.5, 25, 55, 75, 80, or 85.

[0084] 3.0<(V3+V4) / V5<6.0; V3 is the Abbe number of the third lens L3 under d light, V4 is the Abbe number of the fourth lens L4 under d light, and V5 is the Abbe number of the fifth lens L5 under d light. When the above relationship is satisfied, the degree of deflection of light passing through the third lens L3, the fourth lens L4, and the fifth lens L5 can be controlled, which is beneficial to enhance the lens aberration correction capability and suppress the dispersion problem generated when the light passes through these lenses, thereby balancing the chromatic aberration of the optical system 10. In some embodiments, the relationship satisfied by the optical system 10 can be 3.9, 3.95, 4, 4.05, 4.3, 4.6, 4.8, 5, 5.04, 5.1, 5.13 or 5.17.

[0085] 0.3<R10 / R11<0.8; R10 is the radius of curvature of the object side surface S9 of the fifth lens L5 at the optical axis, and R11 is the radius of curvature of the image side surface S10 of the fifth lens L5 at the optical axis. When the above relationship is satisfied, the relationship between the radii of curvature of the object side surface S9 and the image side surface S10 of the fifth lens L5 can be reasonably constrained, so that the light deflection angle borne by the lens can be effectively distributed, and the off-axis field of view astigmatism can be improved, making the imaging surface S15 flatter, thereby improving the imaging quality of the optical system 10. In some embodiments, the relationship satisfied by the optical system 10 can be 0.42, 0.45, 0.48, 0.53, 0.6, 0.64, 0.67, 0.69 or 0.71.

[0086] 3.0<|f7| / R14<9.0; f7 is the effective focal length of the seventh lens L7, and R14 is the radius of curvature of the object side surface S13 of the seventh lens L7 at the optical axis. When the above relationship is satisfied, the relationship between the effective focal length of the seventh lens L7 and the radius of curvature of the object side surface S13 at the optical axis can be reasonably configured to reduce the incident angle of light on the image sensor, so that the optical system 10 can be better matched with common image sensors, and serious ghost image stray light can also be avoided. In some embodiments, the relationship satisfied by the optical system 10 can be 4.0, 4.15, 4.37, 4.8, 5.2, 5.45, 6, 6.75, 7.44, 7.68, 7.89 or 8.05.

[0087] The reference wavelength of the parameters related to focal length, refractive index and Abbe number in the above relationship conditions is 587.6nm, that is, the wavelength of d light. In addition, the above focal length parameters at least represent the focal length of the corresponding lens at the near optical axis.

[0088] The above relationship conditions and the technical effects brought about are for the seven-lens optical system 10 with the above lens design. When the lens design (number of lenses, refractive power configuration, surface configuration, etc.) of the above optical system 10 cannot be ensured, it will be difficult to ensure that the optical system 10 can still have the corresponding technical effects when these relationship conditions are met, and there is even the possibility that the camera performance will be significantly reduced.

[0089] The optical system 10 includes an aperture stop STO, which is used to control the amount of light entering the optical system 10 and can also block ineffective light. When the projection of the aperture stop STO on the optical axis 101 overlaps with the projection of the object side surface S1 of the first lens L1 on the optical axis 101, it can also be considered that the aperture stop STO is arranged on the object side of the first lens L1, and at this time, at least a part of the object side surface S1 of the first lens L1 passes through the aperture stop STO toward the object side. The aperture stop STO can be arranged on the object side of the first lens L1, and can also be arranged between two adjacent lenses from the first lens L1 to the seventh lens L7. The aperture stop STO can be formed by a lens barrel structure that clamps the lens, or it can be a gasket separately assembled between the lens and the lens barrel.

[0090] In some embodiments, the object side surface and / or image side surface of at least one of the first lens L1 to the seventh lens L7 is an aspheric surface, that is, at least one of the first lens L1 to the seventh lens L7 has an aspheric surface shape. For example, the object side surface and the image side surface of the first lens L1 to the seventh lens L7 can be designed as aspheric surfaces. The aspheric surface shape setting can further help the optical system 10 eliminate aberrations and solve the problem of visual field distortion. It is also beneficial to the miniaturization design of the optical system 10, so that the optical system 10 can have excellent optical effects while maintaining the miniaturization design. Of course, in other embodiments, the object side surface and / or image side surface of at least one of the first lens L1 to the seventh lens L7 can also be a spherical surface. It should be noted that the actual surface shape of the lens is not limited to the shape of the spherical or aspheric surface shown in the accompanying drawings. The accompanying drawings are only for example reference and are not strictly drawn to scale. It should also be noted that when the object side surface or the image side surface of a lens is an aspheric surface, the surface can be a structure that is convex as a whole or concave as a whole. Alternatively, the surface can also be designed to have an inflection point. In this case, the surface shape from the center to the edge will change, for example, the surface is convex at the center and concave at the edge. Specifically, the object side surface S11 of the sixth lens L6 in the present application has an inflection point. This is only an example made to illustrate the relationship between the near optical axis and the circumference. The specific surface structure (convex-concave relationship) of any surface of any lens can be diverse and is not limited to the above example.

[0091] The calculation of the aspheric surface can refer to the aspheric surface formula:

[0092]

[0093] Among them, Z is the distance from the corresponding point on the aspheric surface to the tangent plane of the surface at the optical axis, r is the distance from the corresponding point on the aspheric surface to the optical axis, c is the curvature of the aspheric surface at the optical axis, k is the cone coefficient, and Ai is the coefficient of the high-order term corresponding to the i-th high-order term in the aspheric surface shape formula.

[0094] On the other hand, 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. Plastic lenses can reduce the weight of the optical system 10 and reduce the production cost, while glass lenses can withstand higher temperatures and have excellent optical effects. In other embodiments, the material of the first lens L1 is glass, and the materials of the second lens L2 to the seventh lens L7 are all plastic. At this time, since the material of the lens located on the object side of the optical system 10 is glass, the glass lens located on the object side has a good tolerance effect on extreme environments and is not easily affected by the object side environment and aging. Therefore, when the optical system 10 is in an extreme environment such as exposure to high temperature, this structure can better balance the optical performance and cost of the optical system 10. In some embodiments, at least one of the first lens L1 to the seventh lens L7 is made of plastic, and at least one of them is made of glass. 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. The specific design can be determined according to actual needs.

[0095] In some embodiments, the optical system 10 includes an infrared cut-off filter 110, which is disposed on the image side of the seventh lens L7 and is fixed 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 optical system 10, thereby preventing the infrared light from interfering with normal imaging. The infrared cut-off filter 110 can be assembled together with each lens as a part of the optical system 10. In other embodiments, the infrared cut-off filter 110 does not belong to the components of the optical system 10, and 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. In some embodiments, the infrared cut-off filter 110 can also be disposed on the object side of the first lens L1. In addition, in some embodiments, the function of filtering out infrared light can also be achieved by providing a filter coating on at least one lens from the first lens L1 to the seventh lens L7.

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

[0097] First embodiment

[0098] refer to Figure 1and Figure 2 In the first embodiment, the optical system 10 includes, in order from the object side to the image side along the optical axis 101, 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 positive refractive power, and a seventh lens L7 with negative refractive power. Figure 2 The longitudinal spherical aberration diagram, astigmatism diagram and distortion diagram of the optical system 10 in the first embodiment are included, and the reference wavelength of the astigmatism diagram and the distortion diagram in the following embodiments is 587.56 nm.

[0099] The object-side surface S1 of the first lens L1 is convex near the optical axis, and the image-side surface S2 is concave near the optical axis; the object-side surface S1 is convex near the circumference, and the image-side surface S2 is convex near the circumference.

[0100] The object-side surface S3 of the second lens L2 is convex near the optical axis, and the image-side surface S4 is concave near the optical axis; the object-side surface S3 is concave near the circumference, and the image-side surface S4 is convex near the circumference.

[0101] The object-side surface S5 of the third lens L3 is concave near the optical axis, and the image-side surface S6 is convex near the optical axis; the object-side surface S5 is concave near the circumference, and the image-side surface S6 is convex near the circumference.

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

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

[0104] The object-side surface S11 of the sixth lens L6 is convex near the optical axis, and the image-side surface S12 is convex near the optical axis; the object-side surface S11 is concave near the circumference, and the image-side surface S12 is convex near the circumference.

[0105] The object-side surface S13 of the seventh lens L7 is convex near the optical axis, and the image-side surface S14 is concave near the optical axis; the object-side surface S13 is concave near the circumference, and the image-side surface S14 is convex near the circumference.

[0106] The refractive power and surface shape of each lens distributed from the object side to the image side are reasonably matched, so that the aberration can be well corrected to improve the imaging quality of the optical system 10, and it is also beneficial to compress the size of the optical system 10 in the optical axis direction. The configuration of multiple lenses in a positive and negative refractive power cycle can facilitate the aberrations generated by each lens to be corrected in sequence and smoothly, and can better avoid the problem of undercorrection or overcorrection. In particular, by making the object side surface S11 of the sixth lens L6 meet the above-mentioned surface shape setting, the deflection of the light in the edge field of view can be effectively suppressed, that is, the incident angle of the light in the edge field of view on the imaging surface S15 of the optical system 10 is reduced, which is beneficial to alleviate the dark corner problem of edge imaging under a large field of view; at the same time, it can also effectively improve spherical aberration, and well correct off-axis coma and astigmatism.

[0107] The lens parameters of the optical system 10 in this embodiment are given in the following Tables 1 and 2. Table 2 shows the aspheric coefficients of the corresponding lens surfaces in Table 1, where K is the cone coefficient and Ai is the coefficient corresponding to the i-th order high-order term in the aspheric surface formula. The elements from the object side to the image side of the optical system 10 are arranged in order from top to bottom in Table 1. The aperture in the table is the aperture aperture STO, and the infrared filter is the infrared cut-off filter 110. The surfaces corresponding to the surface numbers 2 and 3 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 is the radius of curvature of the corresponding surface of the lens at the optical axis. The absolute value of the first value of the lens in the "Thickness" parameter column is the thickness of the lens on the optical axis, and the absolute value of the second value is the distance from the image side of the lens to the surface of the next optical element (such as the object side or aperture surface of the next lens) on the optical axis. The value of the aperture in the "Thickness" parameter represents the distance from the aperture surface to the object side of the next optical element on the optical axis. The infrared filter in the table is an infrared cutoff filter. In the parameter tables of the following embodiments (the first to the sixth embodiments), the reference wavelength of the refractive index, Abbe number and focal length of each lens is 587.6nm, and the numerical units of the Y radius, thickness, and focal length (effective focal length) are all millimeters (mm). In addition, the relationship calculations and lens structures of each embodiment shall be based on the data provided in the parameter tables (such as Table 1, Table 2, Table 3, Table 4, etc.).

[0108] Table 1

[0109]

[0110] As can be seen from Table 1, the effective focal length f of the optical system 10 is 4.25 mm, the aperture number FNO is 2.2, the half of the maximum field of view HFOV is 43.7°, and the total optical length TTL is 6.0 mm. The rectangular effective pixel area of ​​the image sensor has a diagonal direction. When the image sensor is assembled, HFOV can also be understood as half of the maximum field of view of the optical system 10 parallel to the diagonal direction.

[0111] The materials of the first lens L1 to the seventh lens L7 are all plastic, and the object-side surface and the image-side surface of each lens are aspherical surfaces.

[0112] Table 2

[0113]

[0114]

[0115] In the first embodiment, the optical system 10 also satisfies the following relationships:

[0116] f234 / f1=1.986; f234 is the combined focal length of the second lens L2, the third lens L3 and the fourth lens L4, and f1 is the effective focal length of the first lens L1.

[0117] The optical system 10 having the above-mentioned seven-lens structure design, when further satisfying the above-mentioned relationship conditions, the combined focal length of the second lens L2, the third lens L3 and the fourth lens L4 can be reasonably constrained with the effective focal length of the first lens L1. On the one hand, the focusing ability of the optical system 10 on incident light can be enhanced, thereby facilitating shortening the overall length of the optical system 10, while also obtaining a larger field of view. On the other hand, the positive and negative lens combination can offset aberration defects such as spherical aberration generated by each other. The positive refractive power provided by the first lens L1 and the negative refractive power provided by the second lens L2 can also promote the spherical aberration balance of the optical system 10, thereby achieving good imaging quality.

[0118] (R12+R13) / (R12-R13)=-0.733; R12 is the radius of curvature of the object side surface S11 of the sixth lens L6 at the optical axis, and R13 is the radius of curvature of the image side surface S12 of the sixth lens L6 at the optical axis. When the above-mentioned surface configuration and relationship conditions are met, the radius of curvature of the object side surface S11 and the image side surface S12 of the sixth lens L6 at the optical axis can be appropriately configured, so that the surface shapes of the object side surface S11 and the image side surface S12 of the sixth lens L6 can be well controlled to effectively reduce the incident angle of the light of the edge field of view on the imaging surface S15, and further alleviate the problem of dark corners easily generated around the image under large field of view conditions.

[0119] T12 / CT1=0.574; 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 CT1 is the thickness of the first lens L1 on the optical axis. When the above relationship is satisfied, the thickness of the first lens L1 can be reasonably controlled, and there is a suitable assembly space between the first lens L1 and the second lens L2, which is beneficial to the manufacture and assembly of the first lens L1 and maintains the miniaturization characteristics of the lens.

[0120] (T45+CT5) / (CT3+CT4)=0.893; 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, CT3 is the thickness of the third lens L3 on the optical axis, CT4 is the thickness of the fourth lens L4 on the optical axis, and CT5 is the thickness of the fifth lens L5 on the optical axis. When the above relationship is satisfied, the configuration of the lens group in the optical system 10 can be made more compact, so as to effectively shorten the axial dimension of the optical system 10 and maintain the miniaturized design of the optical system 10.

[0121] TTL / ImgH=1.435; TTL is the distance on the optical axis from the object side S1 of the first lens L1 to the imaging surface S15 of the optical system 10, and ImgH is half of the image height corresponding to the maximum field angle of the optical system 10. When the image sensor is assembled, Imgh can also be understood as the distance from the center to the diagonal edge of the rectangular effective pixel area of ​​the image sensor, and the diagonal direction of the above effective imaging area is parallel to the diagonal direction of the rectangular effective pixel area. When the above conditions are met, the optical system 10 with the above seven-piece design will have a large image surface characteristic, so that it can match the high-pixel image sensor, and thus can meet the high-quality imaging effect; it can also effectively reduce the total length of the optical system 10, thereby realizing the small size design of the optical system 10 in the optical axis direction.

[0122] f / f7=-0.63; f is the effective focal length of the optical system 10, and f7 is the effective focal length of the seventh lens L7. When the above relationship is satisfied, it is helpful to make the principal point of the optical system 10 close to the imaging surface S15, thereby shortening the back focal length of the optical system 10 to maintain miniaturization, and at the same time, the refractive power strength of the seventh lens L7 is appropriate, which can reduce the design complexity of each lens on the object side, and further reduce the tolerance sensitivity of the lens group in the optical system 10.

[0123] f3 / f1=1.317; f1 is the effective focal length of the first lens L1, and f3 is the effective focal length of the third lens L3. The first lens L1 and the third lens L3 both provide positive refractive power to the optical system 10, and when the above relationship is satisfied, the effective focal lengths of the first lens L1 and the third lens L3 can be reasonably controlled, so that the positive refractive power of the first lens L1 can be balanced to avoid excessive increase in spherical aberration due to excessive concentration of refractive power on the first lens L1.

[0124] CT6 / |SAG61|=87; CT6 is the thickness of the sixth lens L6 on the optical axis, and SAG61 is the sag height of the object side surface S11 of the sixth lens L6 at the maximum effective aperture. When the above relationship is satisfied, the central thickness of the sixth lens L6 and the edge sag height of the object side surface S11 can be mutually constrained, so as to reduce the surface complexity of the object side surface S11, thereby facilitating the manufacture and molding of the sixth lens L6 and reducing the defect of poor molding of the lens; the field curvature generated by each lens on the object side can also be trimmed to promote the field curvature balance of the optical system 10 and improve the imaging quality of the optical system 10. It should be noted that the sag height of the lens surface at the maximum effective aperture is the distance from the intersection of the surface and the optical axis to the maximum effective aperture in the direction parallel to the optical axis 101.

[0125] (V3+V4) / V5=5.19; V3 is the Abbe number of the third lens L3 under d light, V4 is the Abbe number of the fourth lens L4 under d light, and V5 is the Abbe number of the fifth lens L5 under d light. When the above relationship is satisfied, the degree of deflection of light passing through the third lens L3, the fourth lens L4, and the fifth lens L5 can be controlled, which is beneficial to enhancing the lens aberration correction capability and suppressing the dispersion problem generated when the light passes through these lenses, thereby balancing the chromatic aberration of the optical system 10.

[0126] R10 / R11=0.654; R10 is the radius of curvature of the object side surface S9 of the fifth lens L5 at the optical axis, and R11 is the radius of curvature of the image side surface S10 of the fifth lens L5 at the optical axis. When the above relationship is satisfied, the relationship between the radius of curvature of the object side surface S9 and the image side surface S10 of the fifth lens L5 can be reasonably constrained, so that the light deflection angle borne by the lens can be effectively distributed, and the off-axis field of view astigmatism can be improved, so that the imaging surface S15 is flatter, thereby improving the imaging quality of the optical system 10.

[0127] |f7| / R14=3.968; f7 is the effective focal length of the seventh lens L7, and R14 is the radius of curvature of the object-side surface S13 of the seventh lens L7 at the optical axis. When the above relationship is satisfied, the relationship between the effective focal length of the seventh lens L7 and the radius of curvature of the object-side surface S13 at the optical axis can be reasonably configured to reduce the incident angle of light on the image sensor, so that the optical system 10 can be better matched with common image sensors, and the generation of serious ghost light can also be avoided.

[0128] in addition, Figure 2The optical system 10 includes a longitudinal spherical aberration diagram (Longitudinal Spherical Aberration), which indicates the deviation of the convergence focus of light of different wavelengths after passing through the lens. The ordinate of the longitudinal spherical aberration diagram indicates the normalized pupil coordinate (Normalized Pupil Coordinator) from the center of the pupil to the edge of the pupil, and the abscissa indicates the distance from the imaging plane to the intersection of the light and the optical axis (in mm). It can be seen from the longitudinal spherical aberration diagram that the degree of deviation of the convergence focus of light of each wavelength in the first embodiment tends to be consistent, and the diffuse spots or color halos in the imaging picture are effectively suppressed. Figure 2 Also included is a field curvature diagram (Astigmatic Field Curves) of the optical system 10, where the S curve represents the sagittal field curvature at 587.56nm, and the T curve represents the meridian field curvature at 587.56nm. As can be seen from the figure, the field curvature of the optical system 10 is small, the field curvature and astigmatism of each field of view are well corrected, and the center and edge of the field of view have clear imaging. Figure 2 The optical system 10 also includes a distortion diagram (Distortion). It can be seen from the diagram that the image deformation caused by the main light beam is small, and the imaging quality of the optical system 10 is excellent.

[0129] Second embodiment

[0130] refer to Figure 3 and Figure 4 In the second embodiment, the optical system 10 includes, along the optical axis 101 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 positive refractive power, and a seventh lens L7 with negative refractive power. Figure 4 Included are diagrams of longitudinal spherical aberration, astigmatism, and distortion of the optical system 10 in the second embodiment.

[0131] The object-side surface S1 of the first lens L1 is convex near the optical axis, and the image-side surface S2 is concave near the optical axis; the object-side surface S1 is convex near the circumference, and the image-side surface S2 is convex near the circumference.

[0132] The object-side surface S3 of the second lens L2 is convex near the optical axis, and the image-side surface S4 is concave near the optical axis; the object-side surface S3 is concave near the circumference, and the image-side surface S4 is convex near the circumference.

[0133] The object-side surface S5 of the third lens L3 is concave near the optical axis, and the image-side surface S6 is convex near the optical axis; the object-side surface S5 is concave near the circumference, and the image-side surface S6 is convex near the circumference.

[0134] The object-side surface S7 of the fourth lens L4 is concave at the near optical axis, and the image-side surface S8 is convex at the near optical axis; the object-side surface S7 is concave near the circumference, and the image-side surface S8 is convex near the circumference.

[0135] The object-side surface S9 of the fifth lens L5 is concave at the near optical axis, and the image-side surface S10 is convex at the near optical axis; the object-side surface S9 is concave near the circumference, and the image-side surface S10 is convex near the circumference.

[0136] The object-side surface S11 of the sixth lens L6 is convex near the optical axis, and the image-side surface S12 is concave near the optical axis; the object-side surface S11 is concave near the circumference, and the image-side surface S12 is convex near the circumference.

[0137] The object-side surface S13 of the seventh lens L7 is convex near the optical axis, and the image-side surface S14 is concave near the optical axis; the object-side surface S13 is concave near the circumference, and the image-side surface S14 is convex near the circumference.

[0138] In addition, the lens parameters of the optical system 10 in the second embodiment are given in Table 3 and Table 4, wherein the definitions of the structures and parameters can be obtained from the first embodiment and are not described in detail here.

[0139] Table 3

[0140]

[0141] Table 4

[0142]

[0143] The optical system 10 in this embodiment satisfies the following relationship:

[0144]

[0145]

[0146] Depend on Figure 4 As can be seen from the aberration diagram in , the longitudinal spherical aberration, field curvature and distortion of the optical system 10 are all well controlled, so that the optical system 10 of this embodiment has good imaging quality.

[0147] Third embodiment

[0148] refer to Figure 5 and Figure 6In the third embodiment, the optical system 10 includes, from the object side to the image side along the optical axis 101, 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 positive refractive power, and a seventh lens L7 with negative refractive power. Figure 6 Included are diagrams of longitudinal spherical aberration, astigmatism, and distortion of the optical system 10 in the third embodiment.

[0149] The object-side surface S1 of the first lens L1 is convex near the optical axis, and the image-side surface S2 is concave near the optical axis; the object-side surface S1 is convex near the circumference, and the image-side surface S2 is convex near the circumference.

[0150] The object-side surface S3 of the second lens L2 is convex near the optical axis, and the image-side surface S4 is concave near the optical axis; the object-side surface S3 is concave near the circumference, and the image-side surface S4 is convex near the circumference.

[0151] The object-side surface S5 of the third lens L3 is convex near the optical axis, and the image-side surface S6 is convex near the optical axis; the object-side surface S5 is concave near the circumference, and the image-side surface S6 is convex near the circumference.

[0152] The object-side surface S7 of the fourth lens L4 is concave at the near optical axis, and the image-side surface S8 is convex at the near optical axis; the object-side surface S7 is concave near the circumference, and the image-side surface S8 is convex near the circumference.

[0153] The object-side surface S9 of the fifth lens L5 is concave at the near optical axis, and the image-side surface S10 is convex at the near optical axis; the object-side surface S9 is concave near the circumference, and the image-side surface S10 is concave near the circumference.

[0154] The object-side surface S11 of the sixth lens L6 is convex near the optical axis, and the image-side surface S12 is concave near the optical axis; the object-side surface S11 is concave near the circumference, and the image-side surface S12 is convex near the circumference.

[0155] The object-side surface S13 of the seventh lens L7 is convex near the optical axis, and the image-side surface S14 is concave near the optical axis; the object-side surface S13 is concave near the circumference, and the image-side surface S14 is convex near the circumference.

[0156] In addition, the lens parameters of the optical system 10 in the third embodiment are given in Table 5 and Table 6, wherein the definitions of the structures and parameters can be obtained from the first embodiment and are not elaborated here.

[0157] Table 5

[0158]

[0159]

[0160] Table 6

[0161]

[0162] The optical system 10 in this embodiment satisfies the following relationship:

[0163] f234 / f1 1.448 f3 / f1 0.917 (R12+R13) / (R12-R13) -2.714 CT6 / |SAG61| 8.43 T12 / CT1 0.539 (V3+V4) / V5 5.19 (T45+CT5) / (CT3+CT4) 0.85 R10 / R11 0.652 TTL / ImgH 1.459 |f7| / R14 8.093 f / f7 -0.366

[0164] Depend on Figure 6 As can be seen from the aberration diagram in , the longitudinal spherical aberration, field curvature and distortion of the optical system 10 are all well controlled, so that the optical system 10 of this embodiment has good imaging quality.

[0165] Fourth embodiment

[0166] refer to Figure 7 and Figure 8 In the fourth embodiment, the optical system 10 includes, along the optical axis 101 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 8 Included are diagrams of longitudinal spherical aberration, astigmatism, and distortion of the optical system 10 in the fourth embodiment.

[0167] The object-side surface S1 of the first lens L1 is convex near the optical axis, and the image-side surface S2 is concave near the optical axis; the object-side surface S1 is convex near the circumference, and the image-side surface S2 is convex near the circumference.

[0168] The object-side surface S3 of the second lens L2 is convex near the optical axis, and the image-side surface S4 is concave near the optical axis; the object-side surface S3 is concave near the circumference, and the image-side surface S4 is convex near the circumference.

[0169] The object-side surface S5 of the third lens L3 is convex near the optical axis, and the image-side surface S6 is convex near the optical axis; the object-side surface S5 is concave near the circumference, and the image-side surface S6 is convex near the circumference.

[0170] The object-side surface S7 of the fourth lens L4 is concave at the near optical axis, and the image-side surface S8 is convex at the near optical axis; the object-side surface S7 is concave near the circumference, and the image-side surface S8 is convex near the circumference.

[0171] The object-side surface S9 of the fifth lens L5 is concave at the near optical axis, and the image-side surface S10 is convex at the near optical axis; the object-side surface S9 is concave near the circumference, and the image-side surface S10 is concave near the circumference.

[0172] The object-side surface S11 of the sixth lens L6 is convex near the optical axis, and the image-side surface S12 is concave near the optical axis; the object-side surface S11 is concave near the circumference, and the image-side surface S12 is convex near the circumference.

[0173] The object-side surface S13 of the seventh lens L7 is convex near the optical axis, and the image-side surface S14 is concave near the optical axis; the object-side surface S13 is concave near the circumference, and the image-side surface S14 is convex near the circumference.

[0174] In addition, the lens parameters of the optical system 10 in the fourth embodiment are given in Table 7 and Table 8, wherein the definitions of the structures and parameters can be obtained from the first embodiment and will not be repeated here.

[0175] Table 7

[0176]

[0177] Table 8

[0178]

[0179]

[0180] The optical system 10 in this embodiment satisfies the following relationship:

[0181] f234 / f1 1.975 f3 / f1 0.967 (R12+R13) / (R12-R13) -3.757 CT6 / |SAG61| 7.69 T12 / CT1 0.504 (V3+V4) / V5 3.8 (T45+CT5) / (CT3+CT4) 0.865 R10 / R11 0.406 TTL / ImgH 1.472 |f7| / R14 7.711 f / f7 -0.358

[0182] Depend on Figure 8 As can be seen from the aberration diagram in , the longitudinal spherical aberration, field curvature and distortion of the optical system 10 are all well controlled, so that the optical system 10 of this embodiment has good imaging quality.

[0183] Fifth embodiment

[0184] refer to Fig. 9 and Fig.10 In the fifth embodiment, the optical system 10 includes, in sequence from the object side to the image side along the optical axis 101, 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. Fig.10 Included are diagrams of longitudinal spherical aberration, astigmatism, and distortion of the optical system 10 in the fifth embodiment.

[0185] The object-side surface S1 of the first lens L1 is convex near the optical axis, and the image-side surface S2 is concave near the optical axis; the object-side surface S1 is convex near the circumference, and the image-side surface S2 is concave near the circumference.

[0186] The object-side surface S3 of the second lens L2 is convex near the optical axis, and the image-side surface S4 is concave near the optical axis; the object-side surface S3 is concave near the circumference, and the image-side surface S4 is concave near the circumference.

[0187] The object-side surface S5 of the third lens L3 is convex near the optical axis, and the image-side surface S6 is convex near the optical axis; the object-side surface S5 is concave near the circumference, and the image-side surface S6 is convex near the circumference.

[0188] The object-side surface S7 of the fourth lens L4 is concave at the near optical axis, and the image-side surface S8 is convex at the near optical axis; the object-side surface S7 is concave near the circumference, and the image-side surface S8 is convex near the circumference.

[0189] The object-side surface S9 of the fifth lens L5 is concave at the near optical axis, and the image-side surface S10 is convex at the near optical axis; the object-side surface S9 is concave near the circumference, and the image-side surface S10 is concave near the circumference.

[0190] The object-side surface S11 of the sixth lens L6 is convex near the optical axis, and the image-side surface S12 is concave near the optical axis; the object-side surface S11 is concave near the circumference, and the image-side surface S12 is convex near the circumference.

[0191] The object-side surface S13 of the seventh lens L7 is convex near the optical axis, and the image-side surface S14 is concave near the optical axis; the object-side surface S13 is concave near the circumference, and the image-side surface S14 is convex near the circumference.

[0192] In addition, the lens parameters of the optical system 10 in the fifth embodiment are given in Tables 9 and 10, wherein the definitions of the structures and parameters can be obtained from the first embodiment and will not be elaborated here.

[0193] Table 9

[0194]

[0195]

[0196] Table 10

[0197]

[0198] The optical system 10 in this embodiment satisfies the following relationship:

[0199] f234 / f1 2.263 f3 / f1 0.95 (R12+R13) / (R12-R13) -4.231 CT6 / |SAG61| 8.87 T12 / CT1 0.464 (V3+V4) / V5 4.02 (T45+CT5) / (CT3+CT4) 0.825 R10 / R11 0.721 TTL / ImgH 1.426 |f7| / R14 4.311 f / f7 -0.568

[0200] Depend on Fig.10 As can be seen from the aberration diagram in , the longitudinal spherical aberration, field curvature and distortion of the optical system 10 are all well controlled, so that the optical system 10 of this embodiment has good imaging quality.

[0201] Sixth embodiment

[0202] refer to Fig.11 and Fig.12 In the sixth embodiment, the optical system 10 includes, from the object side to the image side along the optical axis 101, 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 positive refractive power, and a seventh lens L7 with negative refractive power. Fig.12 Included are diagrams of longitudinal spherical aberration, astigmatism, and distortion of the optical system 10 in the sixth embodiment.

[0203] The object-side surface S1 of the first lens L1 is convex near the optical axis, and the image-side surface S2 is concave near the optical axis; the object-side surface S1 is convex near the circumference, and the image-side surface S2 is concave near the circumference.

[0204] The object-side surface S3 of the second lens L2 is convex near the optical axis, and the image-side surface S4 is concave near the optical axis; the object-side surface S3 is concave near the circumference, and the image-side surface S4 is concave near the circumference.

[0205] The object-side surface S5 of the third lens L3 is convex near the optical axis, and the image-side surface S6 is convex near the optical axis; the object-side surface S5 is concave near the circumference, and the image-side surface S6 is convex near the circumference.

[0206] The object-side surface S7 of the fourth lens L4 is concave at the near optical axis, and the image-side surface S8 is convex at the near optical axis; the object-side surface S7 is concave near the circumference, and the image-side surface S8 is convex near the circumference.

[0207] The object-side surface S9 of the fifth lens L5 is concave at the near optical axis, and the image-side surface S10 is convex at the near optical axis; the object-side surface S9 is concave near the circumference, and the image-side surface S10 is concave near the circumference.

[0208] The object-side surface S11 of the sixth lens L6 is convex near the optical axis, and the image-side surface S12 is concave near the optical axis; the object-side surface S11 is concave near the circumference, and the image-side surface S12 is convex near the circumference.

[0209] The object-side surface S13 of the seventh lens L7 is convex near the optical axis, and the image-side surface S14 is concave near the optical axis; the object-side surface S13 is concave near the circumference, and the image-side surface S14 is convex near the circumference.

[0210] In addition, the lens parameters of the optical system 10 in the sixth embodiment are given in Table 11 and Table 12, wherein the definitions of the structures and parameters can be obtained from the first embodiment and will not be repeated here.

[0211] Table 11

[0212]

[0213] Table 12

[0214]

[0215]

[0216] The optical system 10 in this embodiment satisfies the following relationship:

[0217] f234 / f1 1.399 f3 / f1 1.67 (R12+R13) / (R12-R13) -1.575 CT6 / |SAG61| 14.2 T12 / CT1 0.559 (V3+V4) / V5 4.02 (T45+CT5) / (CT3+CT4) 0.589 R10 / R11 0.578 TTL / ImgH 1.388 |f7| / R14 6.847 f / f7 -0.443

[0218] Depend on Fig.12 As can be seen from the aberration diagram in , the longitudinal spherical aberration, field curvature and distortion of the optical system 10 are all well controlled, so that the optical system 10 of this embodiment has good imaging quality.

[0219] The optical system 10 in the first to sixth embodiments described above can achieve a lightweight and compact lens through a reasonable combination design of the refractive power, structure, and parameter relationship of the seven lenses. In addition, it can also achieve excellent correction of the aberrations of the optical system 10 and effectively reduce the incident angle of the edge field light on the imaging surface S15, thereby alleviating the problem of dark corners easily generated around the image under a large field of view, and maintaining high-pixel imaging quality.

[0220] refer to Fig.13 Some embodiments of the present application further provide a camera module 20, which may include an optical system 10 and an image sensor 210, wherein the image sensor 210 is disposed on the image side of the optical system 10. The image sensor 210 may be a CCD sensor (Charge Coupled Device) or a CMOS sensor (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.

[0221] By adopting the above-mentioned optical system 10, the axial size of the camera module 20 can be compressed to achieve a miniaturized design, while also obtaining a larger field of view angle. It is also beneficial to achieve a balance in spherical aberration and alleviate the dark corner problem of edge imaging under a large field of view, thereby achieving good imaging quality.

[0222] refer to Fig.14, some embodiments of the present application also provide an electronic device 30. The electronic device 30 includes a fixing part 310, and the camera module 20 is installed on the fixing part 310. The fixing part 310 can be a display screen, a circuit board, a middle frame, a back cover and other components. The electronic device 30 can be, but is not limited to, a smart phone, a smart watch, smart glasses, an e-book reader, a vehicle-mounted camera 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-mentioned camera module 20, the electronic device 30 can assemble the camera module 20 in a smaller space. At the same time, since the axial size of the camera module can be compressed and it has good imaging quality, it is also beneficial for the device to achieve a thin design while having good shooting quality.

[0223] 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.

[0224] 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: The optical system has seven lenses with refractive power, and the optical system includes, in order from the object side to the image side along the optical axis: A first lens having positive refractive power, wherein the object side surface of the first lens is convex at the near optical axis, and the image side surface of the first lens is concave at the near optical axis; a second lens having negative refractive power, wherein the object side surface of the second lens is convex at a position close to the optical axis; a third lens element having positive refractive power, wherein the image side surface of the third lens element is convex at the near optical axis; a fourth lens having a refractive power, wherein the object side surface of the fourth lens is concave at the near optical axis, and the image side surface of the fourth lens is convex at the near optical axis; a fifth lens element having negative refractive power, wherein the object side surface of the fifth lens element is concave at the near optical axis, and the image side surface of the fifth lens element is convex at the near optical axis; a sixth lens having positive refractive power, wherein the object side surface of the sixth lens is convex near the optical axis and is concave near the maximum effective aperture; a seventh lens element having negative refractive power, wherein the object side surface of the seventh lens element is convex at a position close to the optical axis; The optical system satisfies the relationship condition: 1.2<f234 / f1<2.5; 0.8<f3 / f1<1.8; f234 is the combined focal length of the second lens, the third lens and the fourth lens, f1 is the effective focal length of the first lens, and f3 is the effective focal length of the third lens.

2. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: -5.0<(R12+R13) / (R12-R13)<0; R12 is the curvature radius of the object side surface of the sixth lens at the optical axis, and R13 is the curvature radius of the image side surface of the sixth lens at the optical axis.

3. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: 0.4<T12 / CT1<0.65; T12 is the distance from the image side surface of the first lens to the object side surface of the second lens on the optical axis, and CT1 is the thickness of the first lens on the optical axis.

4. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: 0.58<(T45+CT5) / (CT3+CT4)<0.95; T45 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, CT3 is the thickness of the third lens on the optical axis, CT4 is the thickness of the fourth lens on the optical axis, and CT5 is the thickness of the fifth lens on the optical axis.

5. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: 1.3<TTL / ImgH<1.5; TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis, and ImgH is half of the image height corresponding to the maximum field angle of the optical system.

6. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: -0.7<f / f7<-0.3; f is the effective focal length of the optical system, and f7 is the effective focal length of the seventh lens.

7. The optical system according to claim 1, characterized in that The image side surface of the second lens is concave at the near optical axis, and / or the image side surface of the seventh lens is concave at the near optical axis.

8. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: 7.0<CT6 / |SAG61|<88.0; CT6 is the thickness of the sixth lens on the optical axis, and SAG61 is the sag height of the object side of the sixth lens at the maximum effective aperture.

9. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: 3.0<(V3+V4) / V5<6.0; V3 is the Abbe number of the third lens under d light, V4 is the Abbe number of the fourth lens under d light, and V5 is the Abbe number of the fifth lens under d light.

10. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: 0.3<R10 / R11<0.8; R10 is the curvature radius of the object side surface of the fifth lens at the optical axis, and R11 is the curvature radius of the image side surface of the fifth lens at the optical axis.

11. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: 3.0<|f7| / R14<9.0; f7 is the effective focal length of the seventh lens, and R14 is the radius of curvature of the object side of the seventh lens at the optical axis.

12. A camera module, characterized in that: The optical system comprises an image sensor and any one of claims 1 to 11, wherein the image sensor is arranged on the image side of the optical system.

13. An electronic device, characterized in that: It comprises a fixing part and the camera module as claimed in claim 12, wherein the camera module is arranged on the fixing part.

Images