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 first lens with positive refractive power, the object side surface of the first lens is convex at the paraxial position, and the image side surface is concave at the paraxial position; a second lens with negative refractive power, the object side surface of the second lens is convex at the paraxial position, and the image side surface is concave at the paraxial position; a third lens, a fourth lens, a fifth lens and a sixth lens with refractive power; a seventh lens with negative refractive power, the image side surface of the seventh lens is concave at the paraxial position; the system satisfies the relationship: Imgh 2 / (TTL*Fno)≥2.3mm; Imgh is half of the image height corresponding to the maximum field angle of the optical system, 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 Fno is the aperture number of the optical system. The above optical system has excellent camera performance and axial miniaturization design.

Description

Technical Field

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

[0002] With the advancement of technology, consumers have higher and higher requirements for the shooting quality of mobile electronic products. Generally speaking, seven-element camera lenses have obvious advantages and can achieve higher resolution, so they are often used in high-end mobile electronic products to improve the picture quality, resolution and clarity of the shooting.

[0003] However, for general electronic products, the market often hopes that the electronic products can not only have excellent camera performance, but also be as thin as possible. However, for camera lenses with a seven-piece structure, due to the large number of lenses, the axial size of this type of lens system is often difficult to reduce, and it is difficult to maintain a short length while meeting excellent camera performance, and thus it is difficult to meet the requirements of electronic products for high camera performance and small thickness. Summary of the invention

[0004] Based on this, it is necessary to provide an optical system, a camera module and an electronic device to solve the problem of how to make the system have excellent camera performance and axial miniaturization design.

[0005] An optical system, comprising, from the object side to the image side, the following:

[0006] A first lens having positive refractive power, wherein the object side surface of the first lens is convex at the paraxial position, and the image side surface of the first lens is concave at the paraxial position;

[0007] 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;

[0008] a third lens having refractive power;

[0009] a fourth lens having a refractive power;

[0010] a fifth lens having refractive power;

[0011] a sixth lens having a refractive power;

[0012] a seventh lens element having negative refractive power, wherein the image side surface of the seventh lens element is concave on the paraxial side;

[0013] The optical system satisfies the relationship:

[0014] Imgh 2 / (TTL*Fno)≥2.3mm;

[0015] Imgh is half of the image height corresponding to the maximum field angle of the optical system, 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 Fno is the aperture number of the optical system.

[0016] In the above optical system, the first lens has positive refractive power at the near axis, which is beneficial to shorten the total length of the system. In addition, the object side surface of the first lens is convex at the near optical axis, which can fully enhance the positive refractive power strength of the system borne by the first lens, and its image side surface is concave at the near axis, forming a meniscus structure at the near axis with the object side surface, which is beneficial to make the rear principal point of the first lens close to the object side, which is beneficial to further shorten the total length of the system.

[0017] The second lens with negative refractive power can be used to well correct the axial chromatic aberration and spherical aberration caused by the first lens. In particular, since the object side surface of the second lens is convex at the near axis and the image side surface is concave at the near axis, it can help prevent the spherical aberration and axial chromatic aberration of the first lens from being overcorrected.

[0018] At the same time, when the optical system satisfies the above-mentioned relationship conditions, the effective imaging area size, total optical length, and aperture number of the system can be reasonably configured. On the one hand, the optical system can have a large image height characteristic to improve the imaging clarity; on the other hand, the total optical length and aperture number of the system can be prevented from being too large, which can not only keep the optical system in a small axial size, but also increase the light throughput of the system to improve the imaging quality, especially in a dark light environment, a clear picture can be obtained. As mentioned above, by satisfying the above-mentioned relationship conditions, the optical system can have excellent camera performance and axial miniaturization design. When it is lower than the lower limit of the relationship, the image plane size of the optical system is too small, which is not conducive to high-definition imaging; on the other hand, the total axial length of the system is too long and not conducive to miniaturization design; in addition, there is also a risk that the luminous flux of the system is too low, which makes it difficult to meet the needs of high-definition and dark light shooting.

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

[0020] f*tan(HFOV)≥5.2mm;

[0021] f is the effective focal length of the optical system, and HFOV is half of the maximum field of view of the optical system. When this relationship is satisfied, the optical system has a larger field of view, which can enable the system to have the characteristics of a large image plane, thereby making the system have the characteristics of high pixels and high definition. In addition, with the characteristics of high light flux of the system, the generation of dark corners can be better suppressed.

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

[0023] TTL / Imgh≤1.4. When this relationship is satisfied, the total optical length of the optical system can be constrained by the image plane size, thereby ensuring that the total length of the system is kept within a small range, thereby enabling the optical system to achieve axial miniaturization design.

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

[0025] 0.3mm≤CT2≤0.4mm;

[0026] CT2 is the thickness of the second lens on the optical axis. When this relationship is satisfied, the center thickness of the second lens is constrained within a reasonable range, which not only enables the lens to have good processing characteristics, but also helps to shorten the total length of the optical system.

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

[0028] Fno≤1.9. When this relationship is satisfied, it can ensure that the optical system has a large aperture characteristic, so that the optical system has sufficient light input to improve the clarity of the captured image, especially in shooting dark scenes such as night scenes and starry sky, it can still have good imaging quality.

[0029] In one embodiment, the optical system satisfies the relationship:

[0030] |R3+R4| / |R9+R10|≤4.5;

[0031] R3 is the radius of curvature of the object side of the second lens at the optical axis, R4 is the radius of curvature of the image side of the second lens at the optical axis, R9 is the radius of curvature of the object side of the fifth lens at the optical axis, and R10 is the radius of curvature of the image side of the fifth lens at the optical axis. When this relationship is satisfied, the sum of the radii of curvature of the two side surfaces of the second lens at the optical axis and the sum of the radii of curvature of the two side surfaces of the fifth lens at the optical axis tend to be close, the deflection of the incident light between the two lenses tends to be gentle, and the incident angle of the incident light when reaching the two lenses can be reduced, thereby effectively reducing the sensitivity of the system and improving the yield of the system.

[0032] In one embodiment, the optical system satisfies the relationship:

[0033] f2 / (f6+f7)≤28;

[0034] f2 is the effective focal length of the second lens, f6 is the effective focal length of the sixth lens, and f7 is the effective focal length of the seventh lens. When this relationship is satisfied, the spherical aberration contributions of the second lens, the sixth lens, and the seventh lens can be reasonably distributed, thereby enabling the optical system to have good imaging quality in the paraxial region.

[0035] In one embodiment, the optical system satisfies the relationship:

[0036] f56 / f≥1.0;

[0037] f56 is the combined focal length of the fifth lens and the sixth lens, and f is the effective focal length of the optical system. When this relationship is satisfied, the combined focal length of the fifth lens and the sixth lens can be constrained by the effective focal length of the system, so that the refractive power of the lens group composed of the fifth lens and the sixth lens will not be too strong, thereby being able to well correct high-order spherical aberration and improve the imaging quality of the system.

[0038] In one embodiment, the optical system satisfies the relationship:

[0039] 0.23mm≤ET1≤0.33mm;

[0040] ET1 is the distance from the maximum effective aperture of the object side of the first lens to the maximum effective aperture of the image side in the direction of the optical axis. When this relationship is satisfied, the edge thickness of the first lens can be well controlled, so that the high-order aberrations of the system can be effectively balanced, the imaging performance of the system can be improved, and the thickness of the lens will not be too thin, which facilitates the molding of the lens.

[0041] In one embodiment, the optical system satisfies the relationship:

[0042] 0.3mm≤ET3≤0.45mm;

[0043] ET3 is the distance from the maximum effective aperture of the object side of the third lens to the maximum effective aperture of the image side in the direction of the optical axis. When this relationship is satisfied, the edge thickness of the third lens can be well controlled, the distortion size of the system can be reasonably controlled, the optical system has good optical performance, and the thickness of the lens is not too thin, which is easy to manufacture.

[0044] In one embodiment, the optical system satisfies the relationship:

[0045] 0.5≤SAG51 / SAG52≤1.5;

[0046] SAG51 is the sag height of the object side of the fifth lens at the maximum effective aperture, and SAG52 is the sag height of the image side of the fifth lens at the maximum effective aperture. When this relationship is satisfied, the difference in the surface shape between the object side and the image side of the fifth lens will not be too large, which is conducive to reducing the tolerance sensitivity of the fifth lens, and is conducive to the processing and molding of the lens, thereby better realizing engineering manufacturing.

[0047] In one embodiment, the optical system satisfies the relationship:

[0048] |V2-V3|≥35;

[0049] V2 is the Abbe number of the second lens, and V3 is the Abbe number of the third lens. When the above relationship is satisfied, the Abbe numbers of the second lens and the third lens are controlled within a reasonable range, which is beneficial to improving the aberration of the system, for example, it is beneficial to eliminate the chromatic aberration of the system, reduce the secondary spectrum of the system, and improve the imaging performance of the system.

[0050] 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 not only have good camera performance, but also realize axial miniaturization design.

[0051] An electronic device comprises a fixing part and the above-mentioned camera module, wherein the camera module is arranged on the fixing part. By adopting the above-mentioned camera module, the electronic device can have good camera performance, especially can improve the image clarity in a dark light environment, and can also avoid the axial dimension of the camera module being too large to hinder the thin design of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A schematic diagram of the structure of an optical system provided in the first embodiment of the present application;

[0053] Figure 2 including a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of the optical system in the first embodiment;

[0054] Figure 3 A schematic diagram of the structure of an optical system provided in the second embodiment of the present application;

[0055] Figure 4 including a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of the optical system in the second embodiment;

[0056] Figure 5 A schematic diagram of the structure of an optical system provided in the third embodiment of the present application;

[0057] Figure 6including a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of the optical system in the third embodiment;

[0058] Figure 7 A schematic diagram of the structure of an optical system provided in a fourth embodiment of the present application;

[0059] Figure 8 including a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of the optical system in the fourth embodiment;

[0060] Fig. 9 A schematic diagram of the structure of an optical system provided in a fifth embodiment of the present application;

[0061] Fig.10 including a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of the optical system in the fifth embodiment;

[0062] Fig.11 A schematic diagram of the structure of an optical system provided in a sixth embodiment of the present application;

[0063] Fig.12 including a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of the optical system in the sixth embodiment;

[0064] Fig.13 A schematic diagram of a camera module provided in one embodiment of the present application;

[0065] Fig.14 A schematic diagram of an electronic device provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] refer to Figure 1 In the embodiment of the present application, 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 from the object side to the image side, wherein the first lens L1 has a positive refractive power, the second lens L2 has a negative refractive power, and the seventh lens L7 has a negative refractive power. 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 of the optical system 10.

[0073] 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 photosensitive element.

[0074] In the embodiment of the present application, 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; 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. The first lens L1 has positive refractive power at the paraxial position, which is beneficial to shorten the total length of the system. In addition, the object side surface S1 of the first lens L1 is convex at the near optical axis, which can fully enhance the positive refractive power strength of the system borne by the first lens L1, and its image side surface S2 is concave at the paraxial position, forming a meniscus structure at the paraxial position with the object side surface S1, which is beneficial to make the rear principal point of the first lens L1 close to the object side, which is beneficial to further shorten the total length of the system.

[0075] The second lens L2 with negative refractive power can be used to well correct the axial chromatic aberration and spherical aberration caused by the first lens L1. In particular, since 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, it can help prevent the spherical aberration and axial chromatic aberration of the first lens L1 from being overcorrected.

[0076] In some embodiments, at least one of the object side surfaces and image side surfaces of the first lens L1 to the seventh lens L7 is an aspheric surface. For example, the object side surfaces and image side surfaces of the first lens L1 to the seventh lens L7 can be designed as aspheric surfaces. The aspheric surface 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 a miniaturized design. Of course, in other embodiments, the object side surface of any one of the first lens L1 to the seventh lens L7 can be a spherical surface or an aspheric surface; the image side surface of any one of the first lens L1 to the seventh lens L7 can be a spherical surface or an aspheric surface. The coordination of the spherical surface and the aspheric surface can also effectively eliminate the aberration problem, so that the optical system 10 has an excellent imaging effect, while improving the flexibility of lens design and assembly. In particular, when the seventh lens L7 is an aspheric lens, it will be beneficial to finally correct the aberrations generated by the front lenses, thereby improving the imaging quality. It should be noted that the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings, which are only for example reference and are not drawn strictly to scale.

[0077] The calculation of the aspheric surface shape can refer to the aspheric surface formula:

[0078]

[0079] 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 order high-order term in the aspherical surface shape formula.

[0080] On the other hand, in some embodiments, when the object side or image side of a lens is an aspheric surface, the surface may be a structure that is convex as a whole or concave as a whole. Alternatively, the surface may also be designed to have a structure with an inflection point, in which case the surface shape of the surface from the center to the edge will change, for example, the surface is convex at the center and concave at the edge. It should be noted that when the embodiments of the present application describe a side of a lens as a convex surface at the optical axis (the central area of ​​the side), it can be understood that the area of ​​the side of the lens near the optical axis is convex, so it can also be considered that the side is convex at the near axis; when describing a side of the lens as a concave surface at the circumference, it can be understood that the area of ​​the side near the maximum effective aperture is concave. For example, when the side is convex at the near axis and is also convex at the circumference, the shape of the side from the center (optical axis) to the edge direction can be a pure convex surface; or it first transitions from the convex shape of the center to the concave shape, and then becomes convex when it is close to the maximum effective aperture. This is only an example to illustrate the relationship between the optical axis and the circumference. The various shape structures (concave and convex relationships) of the side are not fully reflected, but other situations can be deduced based on the above examples and should also be regarded as the content recorded in this application.

[0081] 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 production costs, 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 in the optical system 10 is glass, these glass lenses located on the object side have a good tolerance effect on extreme environments and are not easily affected by the object side environment and aging, etc., so 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 system. Of course, the lens material configuration relationship in the optical system 10 is not limited to the above embodiments. The material of any lens can be plastic or glass, and the specific design can be determined according to actual needs.

[0082] 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 fixedly disposed relative to each lens in the optical system 10. The infrared cut-off filter 110 is used to filter out infrared light to prevent infrared light from reaching the imaging surface S15 of the system, thereby preventing 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. In this case, the infrared cut-off filter 110 can be installed between the optical system 10 and the photosensitive element when the optical system 10 and the photosensitive element are assembled into a camera module. In some embodiments, the infrared cut-off filter 110 can also be disposed on the object side of the first lens L1. 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.

[0083] Further, in the embodiment of the present application, the optical system 10 satisfies the relationship:

[0084] Imgh 2 / (TTL*Fno)≥2.3mm;

[0085] Imgh is half of the image height corresponding to the maximum field angle of the optical system 10, or can also be called half of the diagonal length of the effective imaging area of ​​the imaging surface S15, TTL is the distance from the object side of the first lens L1 to the imaging surface S15 of the optical system 10 on the optical axis, and Fno is the aperture number of the optical system 10. It should be noted that when the optical system 10 is assembled with an image sensor, Imgh can also be understood as half of the diagonal length of the rectangular effective pixel area on the image sensor. Imgh in some embodiments 2 / (TTL*Fno) can be 2.31mm, 2.32mm, 2.33mm, 2.34mm or 2.35mm.

[0086] When the optical system 10 satisfies the above-mentioned relationship conditions, the effective imaging area size, total optical length, and aperture number of the system can be reasonably configured. On the one hand, the optical system 10 can have a large image height characteristic to improve the imaging clarity; on the other hand, the total optical length and aperture number of the system can be prevented from being too large, which can not only keep the optical system 10 in a small axial size, but also increase the light throughput of the system to improve the imaging quality, especially in a dark light environment, a clear picture can be obtained. As mentioned above, by satisfying the above-mentioned relationship conditions, the optical system 10 can have excellent camera performance and axial miniaturization design. When it is lower than the lower limit of the relationship, the image plane size of the optical system 10 is too small, which is not conducive to high-definition imaging; on the other hand, the total axial length of the system is too long and not conducive to miniaturization design; in addition, there is also a risk that the luminous flux of the system is too low, which is difficult to meet the needs of high-definition and dark light shooting.

[0087] 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 effects can be achieved:

[0088] f*tan(HFOV)≥5.2mm; f is the effective focal length of the optical system 10, and HFOV is half of the maximum field of view of the optical system 10. When this relationship is satisfied, the optical system 10 has a larger field of view, which can enable the system to have the characteristics of a large image surface, thereby enabling the system to have the characteristics of high pixels and high definition. In addition, with the characteristics of high light flux of the system, the generation of dark corners can be better suppressed. In some embodiments, f*tan(HFOV) can be 5.25mm, 5.27mm, 5.3mm, 5.35mm, 5.4mm, 5.45mm, 5.5mm, 5.55mm or 5.57mm.

[0089] TTL / Imgh≤1.4. In some embodiments, TTL / Imgh may be 1.28, 1.29, 1.3, 1.31, 1.32, 1.33, 1.34, 1.35 or 1.36. When this relationship is satisfied, the total optical length of the optical system 10 can be constrained by the image plane size, thereby ensuring that the total length of the system is kept within a small range, thereby enabling the optical system 10 to achieve an axial miniaturized design.

[0090] 0.3mm≤CT2≤0.4mm; CT2 is the thickness of the second lens L2 on the optical axis. In some embodiments, CT2 may be 0.31mm, 0.32mm, or 0.33mm. When this relationship is satisfied, the center thickness of the second lens L2 is constrained within a reasonable range, which not only enables the lens to have good processing characteristics, but also helps to shorten the overall length of the optical system 10.

[0091] Fno≤1.9. In some embodiments, Fno may be 1.67, 1.7, 1.72, 1.75, 1.77, 1.8, 1.82 or 1.84. When this relationship is satisfied, it can ensure that the optical system 10 has a large aperture characteristic, so that the optical system 10 has a sufficient amount of light to improve the clarity of the captured image, especially in shooting dark scenes such as night scenes and starry sky, it can still have good imaging quality.

[0092] |R3+R4| / |R9+R10|≤4.5; R3 is the radius of curvature of the object side surface of the second lens L2 at the optical axis, R4 is the radius of curvature of the image side surface of the second lens L2 at the optical axis, R9 is the radius of curvature of the object side surface of the fifth lens L5 at the optical axis, and R10 is the radius of curvature of the image side surface of the fifth lens L5 at the optical axis. In some embodiments, |R3+R4| / |R9+R10| may be 0.45, 0.5, 0.6, 0.65, 0.75, 1, 1.8, 1.9, 2.5, 3, 3.5, 3.7 or 3.9. When this relationship is satisfied, the sum of the radii of curvature of the two side surfaces of the second lens L2 (at the optical axis) and the sum of the radii of curvature of the two side surfaces of the fifth lens L5 (at the optical axis) tend to be close, and the deflection of the incident light between the two lenses tends to be gentle, which can reduce the incident angle of the incident light when it reaches the two lenses, thereby effectively reducing the sensitivity of the system and improving the yield of the system.

[0093] f2 / (f6+f7)≤28; f2 is the effective focal length of the second lens L2, f6 is the effective focal length of the sixth lens L6, and f7 is the effective focal length of the seventh lens L7. In some embodiments, f2 / (f6+f7) may be 0.8, 1, 3, 5, 10, 15, 20, 21, 22, 24, 25, or 25.5. When this relationship is satisfied, the spherical aberration contributions of the second lens L2, the sixth lens L6, and the seventh lens L7 can be reasonably allocated, so that the optical system 10 has good imaging quality in the paraxial region.

[0094] f56 / f≥1.0; f56 is the combined focal length of the fifth lens L5 and the sixth lens L6, and f is the effective focal length of the optical system 10. In some embodiments, f56 / f may be 1.2, 1.25, 1.3, 1.35, 1.4, or 1.45. When this relationship is satisfied, the combined focal length of the fifth lens L5 and the sixth lens L6 can be constrained by the effective focal length of the system, so that the refractive power of the lens group composed of the fifth lens L5 and the sixth lens L6 will not be too strong, so that the high-order spherical aberration can be well corrected and the imaging quality of the system can be improved.

[0095] 0.23mm≤ET1≤0.33mm; ET1 is the distance from the maximum effective aperture of the object side of the first lens L1 to the maximum effective aperture of the image side in the direction of the optical axis. ET1 can also be called the edge thickness of the first lens L1. ET1 in some embodiments can be 0.25mm, 0.27mm, 0.29mm, 0.3mm or 0.32mm. When this relationship is met, the edge thickness of the first lens L1 can be better controlled, so that the high-order aberrations of the system can be effectively balanced, the imaging performance of the system can be improved, and the thickness of the lens will not be too thin, which is easy to shape the lens.

[0096] 0.3mm≤ET3≤0.45mm; ET3 is the distance from the maximum effective aperture of the object side of the third lens L3 to the maximum effective aperture of the image side in the direction of the optical axis. ET3 can also be called the edge thickness of the third lens L3. ET3 in some embodiments can be 0.36mm, 0.37mm, 0.38mm, 0.39mm, 0.4mm or 0.41mm. When this relationship is met, the edge thickness of the third lens L3 can be well controlled, the distortion size of the system can be reasonably controlled, the optical system 10 has good optical performance, and the thickness of the lens is not too thin, which is easy to manufacture.

[0097] 0.5≤SAG51 / SAG52≤1.5; SAG51 is the sag of the object side surface of the fifth lens L5 at the maximum effective aperture, and SAG52 is the sag of the image side surface of the fifth lens L5 at the maximum effective aperture. In some embodiments, SAG51 / SAG52 may be 0.9, 0.92, 0.94, 0.96, 0.98, 1, 1.02, 1.04, 1.06 or 1.08. When this relationship is satisfied, the difference in the surface shape between the object side surface and the image side surface of the fifth lens L5 will not be too large, which is beneficial to reduce the tolerance sensitivity of the fifth lens L5, and is beneficial to the processing and molding of the lens, thereby better realizing engineering manufacturing.

[0098] It should be noted that the vector height of a lens surface is the distance from the center of the surface to the maximum effective aperture of the surface in the direction parallel to the optical axis; when the value is positive, the maximum effective aperture of the surface is located on the image side of the intersection of the surface and the optical axis in the direction parallel to the optical axis of the system; when the value is negative, the maximum effective aperture of the surface is located on the object side of the intersection of the surface and the optical axis in the direction parallel to the optical axis of the system.

[0099] |V2-V3|≥35; V2 is the Abbe number of the second lens L2, and V3 is the Abbe number of the third lens L3. When the above relationship is satisfied, the Abbe numbers of the second lens L2 and the third lens L3 are controlled within a reasonable range, which is beneficial to improving the aberration of the system, for example, eliminating the chromatic aberration of the system, reducing the secondary spectrum of the system, and improving the imaging performance of the system.

[0100] It should be noted that the determination of the ranges of the various relationships satisfied by the above optical system 10 and the corresponding effects are for the aforementioned seven-lens structure.

[0101] Next, the optical system 10 of the present application is described with more specific and detailed embodiments:

[0102] First embodiment

[0103] refer to Figure 1 and Figure 2 In the first embodiment, the optical system 10 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 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 diagram includes a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of the optical system 10 in the first embodiment, wherein the reference wavelength of the astigmatism diagram and the distortion diagram is 555 nm.

[0104] 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; the object-side surface S1 is convex at the circumference, and the image-side surface S2 is concave at the circumference.

[0105] 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; the object-side surface S3 is convex at the circumference, and the image-side surface S4 is concave at the circumference.

[0106] 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; the object-side surface S5 is concave at the circumference, and the image-side surface S6 is convex at the circumference.

[0107] 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; the object-side surface S7 is concave at the circumference, and the image-side surface S8 is convex at the circumference.

[0108] The object-side surface S9 of the fifth lens L5 is concave at the paraxial position, and the image-side surface S10 is concave at the paraxial position; the object-side surface S9 is concave at the circumference, and the image-side surface S10 is convex at the circumference.

[0109] 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; the object-side surface S11 is concave at the circumference, and the image-side surface S12 is convex at the circumference.

[0110] 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; the object-side surface S13 is concave at the circumference, and the image-side surface S14 is convex at the circumference.

[0111] The object side surface and the image side surface of each lens from the first lens L1 to the seventh lens L7 are all aspherical surfaces. By matching the aspherical surface shape of each lens in the optical system 10, the problem of field distortion of the optical system 10 can be effectively solved, and the lens can achieve excellent optical effects in a smaller and thinner case, thereby making the optical system 10 have a smaller volume, which is conducive to the miniaturization design of the optical system 10.

[0112] In addition, the material of each lens in the optical system 10 is plastic. The use of plastic lenses can reduce the manufacturing cost of the optical system 10.

[0113] The lens parameters of the optical system 10 are given in the following Tables 1 and 2. Table 2 shows the aspheric coefficients of the corresponding surfaces of the lenses in Table 1, where k is the cone coefficient and Ai is the coefficient corresponding to the i-th high-order term in the aspheric surface formula. The elements from the object plane to the image plane (imaging plane S15, which can also be understood as the photosensitive surface of the photosensitive element during later assembly) are arranged in the order of the elements from top to bottom in Table 1. 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 in Table 1 is the radius of curvature of the object side surface or the image side surface of the corresponding surface number on the optical axis. The absolute value of the first value 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 surface of the lens to the object side surface of the next optical element on the optical axis. The optical axes of the lenses in the embodiment of the present application are on the same straight line, and the straight line serves as the optical axis of the optical system 10. In addition, the infrared filter in the parameter tables of the following embodiments is the infrared cut-off filter 110.

[0114] Referring to Table 1, in the first embodiment, the effective focal length f of the optical system 10 is 5.96 mm, the aperture number FNO is 1.81, the maximum field angle (ie, the maximum viewing angle in the diagonal direction) FOV is 84°, and the total optical length TTL is 7 mm.

[0115] In addition, in the parameter tables of the following embodiments (the first embodiment to the sixth embodiment), the reference wavelength of the refractive index, Abbe number and focal length of each lens is 555 nm. In addition, the relationship calculation and lens structure of each embodiment shall be based on the lens parameters (such as Table 1, Table 2, Table 3, Table 4, etc.).

[0116] Table 1

[0117]

[0118]

[0119] Table 2

[0120]

[0121] In the first embodiment, the optical system 10 satisfies the following relationships:

[0122] Imgh 2 / (TTL*Fno)=2.34mm;

[0123] Imgh is half of the image height corresponding to the maximum field angle of the optical system 10, or can also be called half of the diagonal length of the effective imaging area of ​​the imaging surface S15, TTL is the distance from the object side of the first lens L1 to the imaging surface S15 of the optical system 10 on the optical axis, and Fno is the aperture number of the optical system 10. It should be noted that when the optical system 10 is assembled with an image sensor, Imgh can also be understood as half of the diagonal length of the rectangular effective pixel area on the image sensor. When the optical system 10 satisfies the above relationship conditions, the effective imaging area size, optical total length, and aperture number of the system can be reasonably configured. On the one hand, the optical system 10 can have a large image height characteristic to improve the imaging clarity; on the other hand, it can also prevent the optical total length and aperture number of the system from being too large, which can not only keep the optical system 10 in a small axial size, but also increase the light throughput of the system to improve the imaging quality, especially in a dark light environment, a picture with good clarity can be obtained. As mentioned above, by satisfying the above relationship conditions, the optical system 10 can have excellent camera performance and axial miniaturization design. When it is lower than the lower limit of the relationship, the image plane size of the optical system 10 is too small, which is not conducive to high-definition imaging; on the other hand, the total axial length of the system is too long and is not conducive to miniaturization design; in addition, there is a risk that the system's luminous flux is too low, which makes it difficult to meet the needs of high-definition and low-light shooting.

[0124] f*tan(HFOV)=5.37mm; f is the effective focal length of the optical system 10, and HFOV is half of the maximum field of view of the optical system 10. When this relationship is satisfied, the optical system 10 has a larger field of view, which can enable the system to have the characteristics of a large image plane, thereby enabling the system to have the characteristics of high pixels and high definition. In addition, with the characteristics of high light flux of the system, the generation of dark corners can be better suppressed.

[0125] TTL / Imgh=1.28. When this relationship is satisfied, the total optical length of the optical system 10 can be constrained by the image plane size, thereby ensuring that the total length of the system is kept within a small range, thereby enabling the optical system 10 to achieve an axial miniaturized design.

[0126] CT2=0.33 mm; CT2 is the thickness of the second lens L2 on the optical axis. When this relationship is satisfied, the center thickness of the second lens L2 is constrained within a reasonable range, which not only enables the lens to have good processing characteristics, but also helps to shorten the overall length of the optical system 10.

[0127] Fno=1.81. When this relationship is satisfied, it can ensure that the optical system 10 has a large aperture characteristic, so that the optical system 10 has sufficient light input to improve the clarity of the captured image, especially in shooting dark scenes such as night scenes and starry sky, it can still have good imaging quality.

[0128] |R3+R4| / |R9+R10|=3.997; R3 is the radius of curvature of the object side surface of the second lens L2 at the optical axis, R4 is the radius of curvature of the image side surface of the second lens L2 at the optical axis, R9 is the radius of curvature of the object side surface of the fifth lens L5 at the optical axis, and R10 is the radius of curvature of the image side surface of the fifth lens L5 at the optical axis. When this relationship is satisfied, the sum of the radii of curvature of the two side surfaces of the second lens L2 (at the optical axis) and the sum of the radii of curvature of the two side surfaces of the fifth lens L5 (at the optical axis) tend to be close, and the deflection of the incident light between the two lenses tends to be gentle, which can reduce the incident angle of the incident light when it reaches the two lenses, thereby effectively reducing the sensitivity of the system and improving the yield of the system.

[0129] f2 / (f6+f7)=21.9; f2 is the effective focal length of the second lens L2, f6 is the effective focal length of the sixth lens L6, and f7 is the effective focal length of the seventh lens L7. When this relationship is satisfied, the spherical aberration contribution of the second lens L2, the sixth lens L6, and the seventh lens L7 can be reasonably distributed, so that the optical system 10 has good imaging quality in the paraxial region.

[0130] f56 / f=1.33; f56 is the combined focal length of the fifth lens L5 and the sixth lens L6, and f is the effective focal length of the optical system 10. When this relationship is satisfied, the combined focal length of the fifth lens L5 and the sixth lens L6 can be constrained by the effective focal length of the system, so that the refractive power of the lens group composed of the fifth lens L5 and the sixth lens L6 will not be too strong, thereby being able to well correct high-order spherical aberration and improve the imaging quality of the system.

[0131] ET1 = 0.32 mm; ET1 is the distance from the maximum effective aperture of the object side of the first lens L1 to the maximum effective aperture of the image side in the direction of the optical axis. When this relationship is met, the edge thickness of the first lens L1 can be well controlled, so that the high-order aberrations of the system can be effectively balanced, the imaging performance of the system can be improved, and the thickness of the lens will not be too thin, which is easy to shape the lens.

[0132] ET3 = 0.37 mm; ET3 is the distance from the maximum effective aperture of the object side of the third lens L3 to the maximum effective aperture of the image side in the direction of the optical axis. When this relationship is satisfied, the edge thickness of the third lens L3 can be well controlled, the distortion size of the system can be reasonably controlled, the optical system 10 has good optical performance, and the thickness of the lens is not too thin, which is easy to manufacture.

[0133] SAG51 / SAG52=0.89; SAG51 is the sag height of the object side surface of the fifth lens L5 at the maximum effective aperture, and SAG52 is the sag height of the image side surface of the fifth lens L5 at the maximum effective aperture. When this relationship is satisfied, the difference between the surface shapes of the object side surface and the image side surface of the fifth lens L5 will not be too large, which is conducive to reducing the tolerance sensitivity of the fifth lens L5, and is conducive to the processing and molding of the lens, thereby better realizing engineering manufacturing.

[0134] |V2-V3|=36.51; V2 is the Abbe number of the second lens L2, and V3 is the Abbe number of the third lens L3. When the above relationship is satisfied, the Abbe numbers of the second lens L2 and the third lens L3 are controlled within a reasonable range, which is beneficial to improving the aberration of the system, for example, it is beneficial to eliminate the chromatic aberration of the system, reduce the secondary spectrum of the system, and improve the imaging performance of the system.

[0135] on the other hand, Figure 2 The 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 555nm, and the T curve represents the meridian field curvature at 555nm. As can be seen from the figure, the field curvature of the system 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 is also included in the 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 system is excellent.

[0136] Second embodiment

[0137] refer to Figure 3 and Figure 4 In the second embodiment, the optical system 10 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 The diagram includes a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of the optical system 10 in the second embodiment, wherein the reference wavelength of the astigmatism diagram and the distortion diagram is 555 nm.

[0138] 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; the object-side surface S1 is convex at the circumference, and the image-side surface S2 is concave at the circumference.

[0139] 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; the object-side surface S3 is convex at the circumference, and the image-side surface S4 is concave at the circumference.

[0140] 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; the object-side surface S5 is concave at the circumference, and the image-side surface S6 is convex at the circumference.

[0141] 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; the object-side surface S7 is concave at the circumference, and the image-side surface S8 is convex at the circumference.

[0142] The object-side surface S9 of the fifth lens L5 is concave at the paraxial position, and the image-side surface S10 is concave at the paraxial position; the object-side surface S9 is concave at the circumference, and the image-side surface S10 is convex at the circumference.

[0143] 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; the object-side surface S11 is concave at the circumference, and the image-side surface S12 is convex at the circumference.

[0144] 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; the object-side surface S13 is concave at the circumference, and the image-side surface S14 is convex at the circumference.

[0145] 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.

[0146] Table 3

[0147]

[0148] Table 4

[0149]

[0150]

[0151] The camera module 10 in this embodiment satisfies the following relationship:

[0152] <![CDATA[Imgh 2 / (TTL*Fno)]]> 2.34 f2 / (f6+f7) 21.60 f*tan(HFOV) 5.59 f56 / f 1.33 TTL / Imgh 1.28 ET1 0.32 CT2 0.31 ET3 0.36 Fno 1.81 SAG51 / SAG52 0.91 |R3+R4| / |R9+R10| 2.450 |V2-V3| 36.51

[0153] 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.

[0154] Third embodiment

[0155] refer to Figure 5 and Figure 6 In the third embodiment, the optical system 10 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. Figure 6 The diagrams include the longitudinal spherical aberration diagram, the astigmatism diagram and the distortion diagram of the optical system 10 in the third embodiment, wherein the reference wavelength of the astigmatism diagram and the distortion diagram is 555 nm.

[0156] 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; the object-side surface S1 is convex at the circumference, and the image-side surface S2 is convex at the circumference.

[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; the object-side surface S3 is convex at the circumference, and the image-side surface S4 is concave at the circumference.

[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; the object-side surface S5 is concave at the circumference, and the image-side surface S6 is convex at the circumference.

[0159] 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; the object-side surface S7 is concave at the circumference, and the image-side surface S8 is convex at the circumference.

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

[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; the object-side surface S11 is concave at the circumference, and the image-side surface S12 is convex at the circumference.

[0162] 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; the object-side surface S13 is concave at the circumference, and the image-side surface S14 is convex at the circumference.

[0163] 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 described in detail here.

[0164] Table 5

[0165]

[0166]

[0167] Table 6

[0168]

[0169] The camera module 10 in this embodiment satisfies the following relationship:

[0170] <![CDATA[Imgh 2 / (TTL*Fno)]]> 2.34 f2 / (f6+f7) 25.89 f*tan(HFOV) 5.29 f56 / f 1.25 TTL / Imgh 1.28 ET1 0.23 CT2 0.32 ET3 0.41 Fno 1.81 SAG51 / SAG52 0.89 |R3+R4| / |R9+R10| 0.647 |V2-V3| 36.51

[0171] 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.

[0172] Fourth embodiment

[0173] refer to Figure 7 and Figure 8 In the fourth embodiment, the optical system 10 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 8 The diagrams include longitudinal spherical aberration diagram, astigmatism diagram and distortion diagram of the optical system 10 in the fourth embodiment, wherein the reference wavelength of the astigmatism diagram and the distortion diagram is 555 nm.

[0174] 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; the object-side surface S1 is convex at the circumference, and the image-side surface S2 is concave at the circumference.

[0175] 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; the object-side surface S3 is convex at the circumference, and the image-side surface S4 is concave at the circumference.

[0176] The object-side surface S5 of the third lens L3 is convex at the paraxial position, and the image-side surface S6 is convex at the paraxial position; the object-side surface S5 is concave at the circumference, and the image-side surface S6 is convex at the circumference.

[0177] 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; the object-side surface S7 is concave at the circumference, and the image-side surface S8 is convex at the circumference.

[0178] 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; the object-side surface S9 is concave at the circumference, and the image-side surface S10 is convex at the circumference.

[0179] 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; the object-side surface S11 is concave at the circumference, and the image-side surface S12 is convex at the circumference.

[0180] The object-side surface S13 of the seventh lens L7 is convex at the paraxial position, and the image-side surface S14 is concave at the paraxial position; the object-side surface S13 is concave at the circumference, and the image-side surface S14 is convex at the circumference.

[0181] 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.

[0182] Table 7

[0183]

[0184]

[0185] Table 8

[0186]

[0187] The camera module 10 in this embodiment satisfies the following relationship:

[0188] <![CDATA[Imgh 2 / (TTL*Fno)]]> 2.31 f2 / (f6+f7) 7.62 f*tan(HFOV) 5.29 f56 / f 1.15 TTL / Imgh 1.28 ET1 0.32 CT2 0.33 ET3 0.37 Fno 1.84 SAG51 / SAG52 0.92 |R3+R4| / |R9+R10| 0.753 |V2-V3| 36.51

[0189] 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.

[0190] Fifth embodiment

[0191] refer to Fig. 9 and Fig.10 In the fifth embodiment, the optical system 10 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 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 The diagrams include longitudinal spherical aberration diagram, astigmatism diagram and distortion diagram of the optical system 10 in the fifth embodiment, wherein the reference wavelength of the astigmatism diagram and the distortion diagram is 555 nm.

[0192] 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; the object-side surface S1 is convex at the circumference, and the image-side surface S2 is concave at the circumference.

[0193] 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; the object-side surface S3 is convex at the circumference, and the image-side surface S4 is concave at the circumference.

[0194] 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; the object-side surface S5 is concave at the circumference, and the image-side surface S6 is convex at the circumference.

[0195] 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; the object-side surface S7 is concave at the circumference, and the image-side surface S8 is convex at the circumference.

[0196] The object-side surface S9 of the fifth lens L5 is concave at the paraxial position, and the image-side surface S10 is concave at the paraxial position; the object-side surface S9 is concave at the circumference, and the image-side surface S10 is convex at the circumference.

[0197] 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; the object-side surface S11 is concave at the circumference, and the image-side surface S12 is convex at the circumference.

[0198] 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; the object-side surface S13 is convex at the circumference, and the image-side surface S14 is convex at the circumference.

[0199] 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.

[0200] Table 9

[0201]

[0202] Table 10

[0203]

[0204]

[0205] The camera module 10 in this embodiment satisfies the following relationship:

[0206] <![CDATA[Imgh 2 / (TTL*Fno)]]> 2.34 f2 / (f6+f7) 22.51 f*tan(HFOV) 5.32 f56 / f 1.42 TTL / Imgh 1.29 ET1 0.33 CT2 0.33 ET3 0.36 Fno 1.81 SAG51 / SAG52 0.90 |R3+R4| / |R9+R10| 1.811 |V2-V3| 36.51

[0207] 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.

[0208] Sixth embodiment

[0209] refer to Fig.11 and Fig.12 In the sixth embodiment, the optical system 10 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. Fig.12 The diagrams include longitudinal spherical aberration diagram, astigmatism diagram and distortion diagram of the optical system 10 in the sixth embodiment, wherein the reference wavelength of the astigmatism diagram and the distortion diagram is 555 nm.

[0210] 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; the object-side surface S1 is convex at the circumference, and the image-side surface S2 is concave at the circumference.

[0211] 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; the object-side surface S3 is convex at the circumference, and the image-side surface S4 is concave at the circumference.

[0212] 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; the object-side surface S5 is concave at the circumference, and the image-side surface S6 is convex at the circumference.

[0213] The object-side surface S7 of the fourth lens L4 is concave at the paraxial position, and the image-side surface S8 is concave at the paraxial position; the object-side surface S7 is concave at the circumference, and the image-side surface S8 is convex at the circumference.

[0214] 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; the object-side surface S9 is concave at the circumference, and the image-side surface S10 is convex at the circumference.

[0215] 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; the object-side surface S11 is concave at the circumference, and the image-side surface S12 is convex at the circumference.

[0216] The object-side surface S13 of the seventh lens L7 is convex at the paraxial position, and the image-side surface S14 is concave at the paraxial position; the object-side surface S13 is concave at the circumference, and the image-side surface S14 is convex at the circumference.

[0217] 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.

[0218] Table 11

[0219]

[0220] Table 12

[0221]

[0222]

[0223] The camera module 10 in this embodiment satisfies the following relationship:

[0224] <![CDATA[Imgh 2 / (TTL*Fno)]]> 2.35 f2 / (f6+f7) 0.70 f*tan(HFOV) 5.25 f56 / f 1.48 TTL / Imgh 1.36 ET1 0.28 CT2 0.31 ET3 0.40 Fno 1.67 SAG51 / SAG52 1.08 |R3+R4| / |R9+R10| 0.419 |V2-V3| 36.51

[0225] 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.

[0226] refer to Fig.13 Some embodiments of the present application further provide a camera module 20, which may include the optical system 10 and the image sensor 210 of any of the above embodiments, and the image sensor 210 is arranged on the image side of the optical system 10. The image sensor 210 may be a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). Generally, during assembly, the imaging surface S15 of the optical system 10 coincides with the photosensitive surface of the image sensor 210.

[0227] In some embodiments, the camera module 20 includes an infrared cutoff filter 110 disposed between the seventh lens L7 and the image sensor 210, and the infrared cutoff filter 110 is used to filter out infrared light. In some embodiments, the infrared cutoff filter 110 can be mounted to the image end of the lens. In some embodiments, the camera module 20 also includes a protective glass, which is disposed between the infrared cutoff filter and the image sensor 210, and the protective glass is used to protect the image sensor 210.

[0228] By adopting the above optical system 10, the camera module 20 can have the characteristics of a large image surface, high light flux and a small axial size, so that it can not only have good camera performance, but also realize axial miniaturization design. In particular, since the camera module 20 has the characteristics of high light flux, it can improve the shooting clarity in a dark environment.

[0229] refer to Fig.14 , some embodiments of the present application also provide an electronic device 30, and the camera module 20 is applied to the electronic device 30. Specifically, the electronic device 30 includes a fixing member 310, and the camera module 20 is installed on the fixing member 310, and the fixing member 310 can be 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 will have good camera performance, and can improve the shooting clarity in a dark light environment. In addition, it can also prevent the axial size of the module from causing a large restriction on the thickness reduction of the device, thereby facilitating the thinning design of the device. In particular, when the electronic device 30 is a smart phone, the axial small size design of the above-mentioned camera module 20 can promote the ultra-thin design of the device.

[0230] 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.

[0231] 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 is composed of seven lenses with refractive power, and the optical system includes, from the object side to the image side: A first lens having positive refractive power, wherein the object side surface of the first lens is convex at the paraxial position, and the image side surface of the first lens is concave 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 positive refractive power, wherein the object side surface of the sixth lens is convex at the paraxial position; a seventh lens element having negative refractive power, wherein the image side surface of the seventh lens element is concave on the paraxial side; The optical system satisfies the relationship: ,1.0≤f56 / f≤1.48; Imgh is half of the image height corresponding to the maximum field of view of the optical system, TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis, Fno is the aperture number of the optical system, f56 is the combined focal length of the fifth lens and the sixth lens, and f is the effective focal length of the optical system.

2. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: ； f is the effective focal length of the optical system, and HFOV is half of the maximum field of view of the optical system.

3. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: 1.28≤TTL / Imgh≤1.

4.

4. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: 0.3mm≤CT2≤0.4mm; CT2 is the thickness of the second lens on the optical axis.

5. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: 1.67≤Fno≤1.

9.

6. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: 0.419≤|R3+R4| / |R9+R10|≤4.5; R3 is the curvature radius of the object side of the second lens at the optical axis, R4 is the curvature radius of the image side of the second lens at the optical axis, R9 is the curvature radius of the object side of the fifth lens at the optical axis, and R10 is the curvature radius of the image side of the fifth lens at the optical axis.

7. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: 0.70≤f2 / (f6+f7)≤28; f2 is the effective focal length of the second lens, f6 is the effective focal length of the sixth lens, and f7 is the effective focal length of the seventh lens.

8. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: 0.23mm≤ET1≤0.33mm; ET1 is the distance from the maximum effective aperture of the object side of the first lens to the maximum effective aperture of the image side in the direction of the optical axis.

9. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: 0.3mm≤ET3≤0.45mm; ET3 is the distance from the maximum effective aperture of the object side of the third lens to the maximum effective aperture of the image side in the direction of the optical axis.

10. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: 0.5≤SAG51 / SAG52≤1.5; SAG51 is the sag of the object side of the fifth lens at the maximum effective aperture, and SAG52 is the sag of the image side of the fifth lens at the maximum effective aperture.

11. The optical system according to claim 1, characterized in that The optical system satisfies the relationship: |V2-V3|≥35; V2 is the Abbe number of the second lens, and V3 is the Abbe number of the third lens.

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.

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