CN114153050B

CN114153050B - Optical system, image capturing module and electronic device with same

Info

Publication number: CN114153050B
Application number: CN202111509163.9A
Authority: CN
Inventors: 龙鑫灿; 李明
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2021-12-10
Filing date: 2021-12-10
Publication date: 2023-07-04
Anticipated expiration: 2041-12-10
Also published as: CN114153050A

Abstract

The invention discloses an optical system, an image capturing module with the optical system and an electronic device, wherein the optical system comprises: the optical system comprises a first lens with positive focal power, a second lens with negative focal power, a third lens with positive focal power, a fourth lens with focal power, a fifth lens with negative focal power, a sixth lens with focal power and a seventh lens with focal power, wherein the object side of the first lens is a convex surface, the object side of the second lens is a convex surface, the image side of the second lens is a concave surface, the object side of the third lens is a convex surface, the image side of the fourth lens is a convex surface, the object side of the fifth lens is a convex surface, the image side of the fifth lens is a concave surface, the object side of the sixth lens is a convex surface, the object side of the seventh lens is a convex surface, and the image side of the seventh lens is a concave surface, wherein the optical system satisfies 2.8< FNO TTL/Imgh <3.5; the optical system according to the invention achieves miniaturization while having a large aperture to accommodate dim light scenes.

Description

Optical system, image capturing module and electronic device with same

Technical Field

The present invention relates to the field of optical imaging technologies, and in particular, to an optical system, an image capturing module and an electronic device with the optical system.

Background

In recent years, along with the wide application of electronic products such as mobile phones, tablet computers, unmanned aerial vehicles, computers and the like in life, people are focusing on improvement and innovation of the shooting effect of the lens in the electronic products. Among them, a lens capable of capturing a bright, strong-quality, high-definition picture is becoming popular with users. On the other hand, the pixel size of the photosensitive elements such as the photocoupler CCD and the CMOS is smaller and smaller along with the technological progress, so that the imaging quality requirement on the matched optical system is higher and higher.

However, the traditional miniaturized lens has weak dim light shooting capability while ensuring imaging definition, and cannot meet shooting requirements of dim light scenes such as night scenes, rainy days, starry sky and the like.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, an object of the present invention is to provide an optical system that is miniaturized while having a large aperture to accommodate a dim light scene.

The optical system according to an embodiment of the present invention sequentially includes, from an object side to an image side along an optical axis: a first lens having positive optical power; the object side surface of the lens is convex at a paraxial region; a second lens having negative optical power; the object side surface is convex at the paraxial region, and the image side surface is concave at the paraxial region; a third lens having positive optical power; the object side surface of the lens is convex at a paraxial region; a fourth lens element with optical power, having a convex image-side surface at a paraxial region; a fifth lens element with negative refractive power having a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region; a sixth lens having optical power; the object side surface of the lens is convex at a paraxial region; a seventh lens having optical power; the object side surface is convex at the paraxial region, and the image side surface is concave at the paraxial region.

In the optical system, the first lens has positive focal power, which is favorable for shortening the total system length of the optical system, thereby being favorable for miniaturization design of the optical system, and further, the object side surface of the first lens is a convex surface at the paraxial region, which is favorable for enhancing the positive focal power of the first lens, thereby being favorable for further shortening the total system length of the optical system; the second lens has negative focal power, and the design of matching the object side surface of the second lens with the convex surface at the paraxial region and the image side surface of the second lens with the concave surface at the paraxial region is beneficial to shortening the total length of the optical system and can well correct aberration; the object side surfaces of the third lens and the sixth lens are convex at the paraxial region, so that the focal power of the optical system can be enhanced, the structural compactness among a plurality of lenses of the optical system is improved, and the miniaturization of the optical system is realized; the fourth lens is designed to correct the astigmatic aberration and distortion generated by the object lens; by means of the design that the fifth lens with negative focal power is provided, the collocation side surface is convex at the paraxial region, and the image side surface is concave at the paraxial region, the image plane bending and distortion of the peripheral portion of the picture can be well corrected. The seventh lens element has a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region, which is advantageous for correcting aberration of the optical system, and can ensure a sufficient assembly space for a back focal point of the optical system.

Optionally, the optical system satisfies the following relation: 2.8< FNO TTL/Imgh <3.5, wherein TTL is the distance between the object side surface of the first lens and the imaging surface of the optical system on the optical axis, imgh is half of the maximum field angle of the optical system corresponding to the image height, and FNO is the f-number of the optical system.

The relation is satisfied, and the optical system can obtain smaller f-number and larger imaging surface, so that the optical system can have enough light entering quantity, more scene contents and rich imaging information can be obtained under the condition of shooting dim light, and meanwhile, the optical system can keep the characteristic of smaller total size. When FNO is less than or equal to 2.8, the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis is too small, the lens arrangement is crowded, and aberration correction of the optical system is not facilitated.

Optionally, the optical system satisfies the following relation: 3.9< f tan (HFOV) <4.4; where f is the effective focal length of the optical system and HFOV is half the maximum field angle of the optical system. The size of the optical system can be effectively compressed by reasonably distributing the total effective focal length of the optical system and the maximum half field angle of the optical system, and the light rays of the edge field of view enter the imaging surface at a smaller incident angle, so that the relative illuminance of the edge of the imaging surface is improved, and the optical system has the characteristic of high definition.

Optionally, the optical system satisfies the following relation: 3.5< (f1+|f2|)/f <4.5; wherein f1 is the focal length of the first lens, f2 is the focal length of the second lens, and f is the effective focal length of the optical system. The relationship is satisfied, and by reasonably controlling the relationship between the focal lengths of the first lens and the second lens and the total effective focal length of the optical system, the excessive optical focal length of the first lens and the second lens can be avoided, the suppression of high-order aberration caused by peripheral beams of an imaging area of the optical system is facilitated, the optical system can satisfy a large field angle range, and meanwhile, the suppression of chromatic aberration difficult to correct can be realized, so that the high-resolution performance of the optical system is realized. When (f1+|f2|)/f is more than or equal to 4.5, the focal power of the first lens and the second lens is insufficient, so that the large-angle light is difficult to be incident into the optical system, and the range of the angle of view of the optical system is not easy to be enlarged; when (f1+|f2|)/f is less than or equal to 3.5, the focal power of the first lens and the second lens is too strong, so that stronger astigmatism and chromatic aberration are easy to generate, and the high-resolution imaging characteristic is not facilitated.

Optionally, the optical system satisfies the following relation: 1.4< (R10+R11)/(R10-R11) <4.4, R10 is the radius of curvature of the object side surface of the fifth lens element at the optical axis, and R11 is the radius of curvature of the image side surface of the fifth lens element at the optical axis. The relationship is satisfied, through the reasonable arrangement of the curvature radiuses of the object side surface and the image side surface of the fifth lens, the bending degree of the fifth lens can be effectively controlled, and the lens shape of the fifth lens is smooth and uniform, so that the assembly sensitivity of the optical system can be reduced, meanwhile, the image quality of the whole imaging surface from the center to the edge of the imaging surface is clear and uniform, the risk of ghost image generation is reduced, and the resolution capability of the optical system is improved.

Optionally, the optical system satisfies the following relation: 10.5< ALT/CT5<13.5; where ALT is the sum of the center thicknesses of the first lens to the seventh lens on the optical axis, and CT5 is the center thickness of the fifth lens on the optical axis. By satisfying the above-described relational expression, the shape of the fifth lens can be effectively restrained by controlling the relation between the thickness of the fifth lens and the sum of the lens thicknesses of the optical system. When ALT/CT5 is less than 10.5, the center thickness of the fifth lens is too thick, so that the field curvature of the imaging surface of the optical system is too large, and the high-quality imaging of the optical system is not facilitated; when ALT/CT5 is more than 13.5, the center thickness of the fifth lens is too thin, which is unfavorable for processing and production, and further reduces the yield of lens molding.

Optionally, the optical system satisfies the following relation: 4< SD72/SD11<4.5; the SD11 is half of the maximum aperture of the object side surface of the first lens element, and the SD72 is half of the maximum aperture of the image side surface of the seventh lens element. By satisfying the relation, the effective aperture of the object side surface of the first lens and the effective aperture of the image side surface of the seventh lens can be reasonably configured, so that the size of the first lens in the radial direction is restrained, the optical system is designed to be small in head, the size of an opening of a screen can be reduced when the optical system is applied to electronic equipment, and the screen occupation ratio of the equipment can be improved; on the other hand, a larger entrance pupil can be provided for the optical system so as to enlarge the aperture, so that the optical system has enough light quantity, and the imaging quality of the optical system is further improved. When SD72/SD11 is more than or equal to 4.5, the outer diameter sizes of an object end and an image end of the optical system are not beneficial to control, on one hand, the light entering aperture of a first lens of the optical system is too small, so that the entrance pupil of the optical system is too small, the aperture is difficult to expand by the optical system, the light passing amount is insufficient, and good image quality is difficult to obtain; on the other hand, the radial dimension of the image end of the optical system is too large, so that the miniaturization design of the optical system is limited, the deflection degree of the light rays with the edge view field in the optical system is too large, the aberration of the optical system is easily increased, and poor imaging is caused. When SD72/SD11 is less than or equal to 4, the light emergent caliber of the seventh lens of the optical system is too small, so that the optical system is difficult to have large image surface characteristics and difficult to match with a large-size image sensor, and the finally assembled camera module is further difficult to realize high-pixel imaging; in addition, the angle of the chief ray of the external field of view when entering the imaging surface is too large, which makes the photosensitive performance of the image sensor difficult to fully develop and tends to increase the risk of occurrence of a dark angle.

Optionally, the optical system 10 satisfies the following relationship: 1< CT3/ET3<2.5; the CT3 is a distance between the object side surface of the third lens element and the image side surface of the third lens element on the optical axis, i.e., a center thickness of the third lens element, and ET3 is a distance between the maximum effective half-caliber of the object side surface of the third lens element and the maximum effective half-caliber of the image side surface of the third lens element along the optical axis, i.e., an edge thickness of the third lens element. By controlling the ratio of the center thickness to the edge thickness of the third lens within the above-described range, the power of the third lens can be controlled, the tilt angle of the third lens can be reduced, and the power balance between the lenses of the optical system can be further realized to balance the aberrations contributed by the lenses. CT3/ET3 is more than or equal to 2.5, and the focal power of the third lens is too large to generate excessive aberration, so that the imaging quality is reduced.

Optionally, the optical system 10 satisfies the following relationship: 1< SAG62/SAG61<4.5; the SAG62 is a distance between an intersection point of the image side surface of the sixth lens element and the optical axis and the maximum effective caliber of the image side surface of the sixth lens element on the optical axis, and the SAG61 is a distance between an intersection point of the object side surface of the sixth lens element and the optical axis and the maximum effective caliber of the object side surface of the sixth lens element on the optical axis. The relationship is satisfied, the shape of the sixth lens can be effectively controlled, the processability of the sixth lens is improved, the trend of the marginal view field rays can be controlled, the camera lens group can be better matched with the corresponding chip, and the imaging quality is improved. SAG62/SAG61 is less than or equal to 1, and the structural sensitivity of the sixth lens is too high, so that aberration correction is not facilitated; SAG62/SAG61 is more than or equal to 4.5, and the image side surface of the sixth lens is excessively bent, so that the molding and demolding of the sixth lens are not facilitated.

Optionally, the optical system 10 satisfies the following relationship: -4< f5/f123< -1; wherein f5 is a focal length of the fifth lens, and f123 is a combined focal length of the first lens, the second lens, and the third lens. The optical power contribution of the first three lenses is reasonably distributed, the light deflection angle is reduced, and the sensitivity of the optical system is reduced. When the relation upper limit is exceeded, the bending force of the front lens group of the optical system is too small, which is not beneficial to the convergence of light rays and the miniaturization of the optical system; when the bending force of the front lens group of the optical system is lower than the lower limit of the relation, the bending force is overlarge, the visual field range of the optical system is not easy to expand, the optical sensitivity of the optical system is overlarge, the manufacturing difficulty is increased, and the production yield is low.

The invention also provides an image capturing module with the optical system of the embodiment.

According to an embodiment of the invention, an image capturing module includes: an optical system and a photosensitive element disposed on an image side of the optical system.

According to the image capturing module provided by the embodiment of the invention, the first lens to the seventh lens of the optical system are arranged in the lens module, and the surface type and the focal power of each lens of the first lens to the seventh lens are reasonably configured, so that the image capturing module can meet the requirement of miniaturization, and the image capturing module can acquire a larger imaging range.

The invention also provides an electronic device with the optical system of the embodiment.

The electronic device comprises a shell and an image capturing module, wherein the image capturing module is arranged on the shell. The electronic device may be a smart phone, a Personal Digital Assistant (PDA), a tablet computer, a smart watch, an unmanned aerial vehicle, an electronic book reader, a vehicle recorder, a wearable device, etc.

According to the electronic device provided by the embodiment of the invention, the imaging module is arranged in the shell, so that the electronic device can meet the miniaturization requirement, and the electronic device can acquire a larger imaging range.

Additional aspects and advantages of the invention according to embodiments of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:

fig. 1 is a schematic structural view of an optical system of a first embodiment of the present application.

Fig. 2 is a graph of spherical aberration, astigmatism and distortion of an optical system according to a first embodiment of the present application.

Fig. 3 is a schematic structural view of an optical system according to a second embodiment of the present application.

Fig. 4 is a graph of spherical aberration, astigmatism and distortion of an optical system according to a second embodiment of the present application.

Fig. 5 is a schematic structural view of an optical system according to a third embodiment of the present application.

Fig. 6 is a graph of spherical aberration, astigmatism and distortion of an optical system according to a third embodiment of the present application.

Fig. 7 is a schematic structural view of an optical system of a fourth embodiment of the present application.

Fig. 8 is a graph of spherical aberration, astigmatism and distortion of an optical system according to a fourth embodiment of the present application.

Fig. 9 is a schematic structural view of an optical system of a fifth embodiment of the present application.

Fig. 10 is a graph of spherical aberration, astigmatism, and distortion of an optical system according to a fifth embodiment of the present application.

Fig. 11 is a schematic structural diagram of an image capturing module according to an embodiment of the disclosure.

Fig. 12 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

Reference numerals:

an electronic device 1000; an image capturing module 100; an optical system 10;

a first lens L1; a second lens L2; a third lens L3; a fourth lens L4; a fifth lens L5; a sixth lens L6; a seventh lens L7;

object side surfaces S2, S5, S7, S9, S11, S13, S15, S17;

image sides S3, S6, S8, S10, S12, S14, S16, S18;

A diaphragm STO; an imaging surface S18; a filter 110; an optical axis 101;

a photosensitive element 20;

and a housing 200.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.

In the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", etc., are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In this application, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, and may also include the first and second features not being in direct contact but being in contact with each other by way of additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is less level than the second feature.

The following disclosure provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. Furthermore, the present application may repeat reference numerals and/or letters in the various examples, which are for the purpose of brevity and clarity, and which do not in themselves indicate the relationship between the various embodiments and/or arrangements discussed. In addition, the present application provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize the application of other processes and/or the use of other materials.

An optical system 10 according to an embodiment of the present invention is described below with reference to fig. 1-10.

As shown in fig. 1, an optical system 10 according to an embodiment of the present invention includes, in order from an object side to an image side along an optical axis 101, a first lens L1 having positive optical power, a second lens L2 having negative optical power, a third lens L3 having positive optical power, a fourth lens L4 having optical power, a fifth lens L5 having negative optical power, a sixth lens L6 having optical power, and a seventh lens L7 having optical power.

The object-side surface S1 of the first lens element L1 is convex at a paraxial region, the object-side surface S3 of the second lens element L2 is convex at a paraxial region, the image-side surface S4 of the second lens element L2 is concave at a paraxial region, the object-side surface S5 of the third lens element L3 is convex at a paraxial region, the image-side surface S9 of the fourth lens element is convex at a paraxial region, the object-side surface S10 of the fifth lens element L5 is convex at a paraxial region, the image-side surface S11 of the fifth lens element L5 is concave at a paraxial region, the object-side surface S12 of the sixth lens element L6 is convex at a paraxial region, the object-side surface S14 of the seventh lens element L7 is convex at a paraxial region, and the image-side surface S15 of the seventh lens element L7 is concave at a paraxial region.

In the optical system 10, the first lens L1 has positive focal power, which is beneficial to shortening the overall length of the optical system 10, thereby being beneficial to miniaturization design of the optical system 10, and further, the object side surface of the first lens L1 is convex at the paraxial region, which is beneficial to enhancing the positive focal power of the first lens L1, thereby being beneficial to further shortening the overall length of the optical system 10; the second lens element L2 has negative refractive power, and a convex object-side surface S3 and a concave image-side surface S4 at paraxial regions of the second lens element L2, respectively, is beneficial to shortening the overall length of the optical system 10 and correcting aberrations; the surface design of the object side surfaces of the third lens element L3 and the sixth lens element L6, which are convex at the paraxial region, can enhance the optical power of the optical system 10, so as to improve the compactness of the structure among the plurality of lenses of the optical system 10 and realize miniaturization of the optical system; the fourth lens L4 is designed to correct aberrations such as astigmatism and distortion generated by the object lens; by designing the fifth lens element with negative power such that the object-side surface S10 is convex at the paraxial region and the image-side surface S11 is concave at the paraxial region, the curvature and distortion of the image plane at the peripheral region of the image can be well corrected. The seventh lens element L7 is disposed in a convex shape at the paraxial region of the object-side surface S14 and a concave shape at the paraxial region of the image-side surface S15, so as to correct the aberration of the optical system 10, and ensure a sufficient assembly space for the back focal point of the optical system 10, so that the surface-type design of the seventh lens element L7 can correct the defects of distortion, astigmatism, curvature of field, etc. generated by the incident light passing through the first lens element L1 to the sixth lens element L6 when the incident light passes through the seventh lens element L7, thereby realizing the low-aberration and high-quality imaging requirements of the optical system 10.

Further, the optical system 10 satisfies the following relation: 2.8< FNO TTL/Imgh <3.5, wherein TTL is the distance between the object side surface S1 of the first lens L1 and the imaging surface S18 of the optical system 10 on the optical axis, imgh is half of the maximum field angle of the optical system 10 corresponding to the image height, and FNO is the f-number of the optical system 10.

Satisfying the above relation can make the optical system 10 obtain a smaller f-number and a larger imaging surface S18, so that the optical system 10 can have a sufficient light entering amount, obtain more scene contents and rich imaging information under the condition of photographing with dark light, and simultaneously the optical system 10 can maintain the characteristic of a smaller overall size. When FNO is equal to or greater than TTL/Imgh and equal to 3.5, the image height of the optical system 10 is too small to match with the large-sized photosensitive element to realize high-pixel imaging, and when FNO is equal to or less than 2.8, the distance from the object side surface S1 of the first lens L1 to the imaging surface S18 of the optical system 10 on the optical axis 101 is too small, so that the lens arrangement is crowded, which is unfavorable for aberration correction of the optical system 10.

Further, the optical system 10 satisfies the following relation: 3.9< f tan (HFOV) <4.4; where f is the effective focal length of the optical system 10 and HFOV is half the maximum field angle of the optical system 10.

The above relation is satisfied, by reasonably distributing the total effective focal length of the optical system 10 and the maximum half field angle of the optical system 10, the size of the optical system 10 can be effectively compressed, and the light rays of the edge field of view enter the imaging surface S18 at a smaller incident angle, which is beneficial to improving the relative illuminance of the edge of the imaging surface S18, so that the optical system 10 has the characteristic of high definition.

Further, the optical system 10 satisfies the following relation: 3.5< (f1+|f2|)/f <4.5; where f1 is the focal length of the first lens L1, f2 is the focal length of the second lens L2, and f is the effective focal length of the optical system 10.

By reasonably controlling the relationship between the focal lengths of the first lens L1 and the second lens L2 and the total effective focal length of the optical system 10, the optical focal lengths of the first lens L1 and the second lens L2 can be prevented from being too strong, which is beneficial to suppressing the higher order aberration caused by the peripheral light beams of the imaging area of the optical system 10, and the optical system 10 can be made to satisfy a large angle of view range while suppressing the chromatic aberration which is difficult to correct, thereby realizing the high resolution performance of the optical system 10. When (f1+|f2|)/f is more than or equal to 4.5, the focal power of the first lens L1 and the second lens L2 is insufficient, so that the large-angle light is difficult to be incident into the optical system 10, and the range of the view angle of the optical system 10 is not easy to be enlarged; when (f1+|f2|)/f is less than or equal to 3.5, the focal power of the first lens L1 and the second lens L2 is too strong, so that stronger astigmatism and chromatic aberration are easy to generate, and the high-resolution imaging characteristic is not facilitated.

Further, the optical system 10 satisfies the following relation: 1.4< (R10+R11)/(R10-R11) <4.4, R10 is the radius of curvature of the object-side surface S10 of the fifth lens element L5 at the optical axis 101, and R11 is the radius of curvature of the image-side surface S11 of the fifth lens element L5 at the optical axis 101.

The above relation is satisfied, by reasonably setting the curvature radius of the object side surface S10 and the image side surface S11 of the fifth lens element L5, the bending degree of the fifth lens element L5 can be effectively controlled, and the lens shape of the fifth lens element L5 is smooth and uniform, so that the assembly sensitivity of the optical system 10 can be reduced, meanwhile, the image quality of the whole imaging surface S18 from the center to the edge of the imaging surface S18 is clear and uniform, the risk of ghost generation is reduced, and the resolving power of the optical system 10 is improved.

Further, the optical system 10 satisfies the following relation: 10.5< ALT/CT5<13.5; where ALT is the sum of the center thicknesses of the first lens L1 to the seventh lens L7 on the optical axis 101, and CT5 is the center thickness of the fifth lens L5 on the optical axis 101.

By satisfying the above-described relational expression, the shape of the fifth lens L5 can be effectively restrained by controlling the relation between the thickness of the fifth lens L5 and the sum of the lens thicknesses of the optical system 10. When ALT/CT5<10.5, the center thickness of the fifth lens L5 is too thick, resulting in too large field curvature of the imaging surface S18 of the optical system 10, which is detrimental to high quality imaging of the optical system 10; when ALT/CT5 is greater than 13.5, the center thickness of the fifth lens L5 is too thin, which is unfavorable for processing and production, and further reduces the yield of lens molding.

Further, the optical system 10 satisfies the following relation: 4< SD72/SD11<4.5; the SD11 is half of the maximum aperture of the object side surface S1 of the first lens element L1, and the SD72 is half of the maximum aperture of the image side surface S15 of the seventh lens element L7.

By satisfying the relation, the effective aperture of the object side surface S1 of the first lens L1 and the image side surface S15 of the seventh lens L7 can be reasonably configured, which is beneficial to restricting the radial dimension of the first lens L1 so as to realize the small-head design of the optical system 10, thereby reducing the aperture size of the screen when the optical system 10 is applied to the electronic device and further improving the screen occupation ratio of the device; on the other hand, a larger entrance pupil can be provided for the optical system 10 to enlarge the aperture, so that the optical system 10 has enough light flux, and further the imaging quality of the optical system 10 is improved. When SD72/SD11 is more than or equal to 4.5, the outer diameter sizes of the object end and the image end of the optical system 10 are not beneficial to control, on one hand, the light entering aperture of the first lens L1 of the optical system 10 is too small, so that the entrance pupil of the optical system 10 is too small, the aperture of the optical system 10 is difficult to expand, the light passing amount is insufficient, and good image quality is difficult to obtain; on the other hand, the radial dimension of the image end of the optical system 10 is too large, which not only limits the miniaturized design of the optical system 10, but also causes the degree of deflection of the light rays of the marginal field of view in the optical system 10 to be too large, which is easy to increase the aberration of the optical system 10 and causes poor imaging. When SD72/SD11 is less than or equal to 4, the light emergent caliber of the seventh lens L7 of the optical system 10 is too small, so that the optical system 10 is difficult to have large image surface characteristics and difficult to match with a large-size image sensor, and the finally assembled camera module is further difficult to realize high-pixel imaging; in addition, the angle at which the principal ray of the external field of view is incident on the imaging surface S18 is too large, which makes it difficult to fully develop the photosensitivity of the image sensor, and increases the risk of occurrence of a dark angle.

Further, the optical system 10 satisfies the following relation: 1< CT3/ET3<2.5; the distance from the object side surface S5 of the third lens element L3 to the image side surface S6 of the third lens element L3 on the optical axis 101 is the center thickness of the third lens element L3, and the distance from the maximum effective half-caliber of the object side surface S5 of the third lens element L3 to the maximum effective half-caliber of the image side surface S6 of the third lens element L3 along the optical axis direction is the edge thickness of the third lens element L3.

By controlling the ratio of the center thickness to the edge thickness of the third lens L3 within the above-described range, the control of the power of the third lens L3 can be achieved, and the plane tilt angle of the third lens L3 can be reduced, and further, the power balance between the respective lenses of the optical system 10 can be achieved to balance the aberrations contributed by the respective lenses. CT3/ET3 is more than or equal to 2.5, and the focal power of the third lens L3 is too large to generate excessive aberration, so that the imaging quality is reduced due to the fact that the excessive aberration cannot be balanced.

Further, the optical system 10 satisfies the following relation: 1< SAG62/SAG61<4.5; the SAG62 is a distance from an intersection point of the image side surface S13 of the sixth lens L6 and the optical axis 101 to a maximum effective caliber of the image side surface S13 of the sixth lens L6 on the optical axis 101, and the SAG61 is a distance from an intersection point of the object side surface S13 of the sixth lens L6 and the optical axis 101 to a maximum effective caliber of the object side surface S13 of the sixth lens L6 on the optical axis 101.

The shape of the sixth lens L6 can be effectively controlled, the processability of the sixth lens L6 is improved, the trend of the marginal view field rays can be controlled, the camera lens group can be better matched with the corresponding chip, and the imaging quality is improved. SAG62/SAG61 is less than or equal to 1, and the structural sensitivity of the sixth lens L6 is too high, so that aberration correction is not facilitated; SAG62/SAG61 is not less than 4.5, and the image side S13 of the sixth lens L6 is excessively bent, which is unfavorable for molding and demolding of the sixth lens L6.

Further, the optical system 10 satisfies the following relation: -4< f5/f123< -1; wherein f5 is a focal length of the fifth lens L5, and f123 is a combined focal length of the first lens L1, the second lens L2, and the third lens L3.

Satisfying the above relation is advantageous for reasonably distributing the power contributions of the first three lenses, reducing the light deflection angle, and reducing the sensitivity of the optical system 10. When the upper limit of the relation is exceeded, the bending force of the front lens group of the optical system 10 is too small, which is not beneficial to the convergence of light rays and the miniaturization of the optical system; when the bending force of the front lens group of the optical system 10 is lower than the lower limit of the relation, the bending force is too large, which is unfavorable for enlarging the field of view of the optical system 10, and the optical sensitivity of the optical system 10 is too large, which increases the manufacturing difficulty and reduces the production yield.

In one example, at least one of the object side surface S14 of the seventh lens L7 and the image side surface S15 of the seventh lens L7 is provided with at least one inflection point. Therefore, the inflection point is arranged on the seventh lens L7, so that off-axis aberration can be corrected, the angle of incidence of light rays of the off-axis view field on the photosensitive element can be effectively pressed, the incidence light rays can be effectively transmitted to the pixel units of the photosensitive element, the photosensitive performance of the pixel units at the edge positions of the photosensitive element is improved, and the resolution of a picture is improved. Therefore, it can be understood that at least one inflection point may be disposed on the object side surface and/or the image side surface of at least one of the first lens L1 to the sixth lens L6 to correct the off-axis aberration, and meanwhile, the angle of incidence of the light in the off-axis field of view onto the photosensitive element may be effectively pressed, so that the incident light may be effectively transmitted to the pixel unit of the photosensitive element, thereby improving the photosensitivity of the pixel unit at the edge of the photosensitive element and improving the resolution of the image.

In some embodiments, at least one lens of the optical system 10 has an aspherical surface profile, i.e., when at least one side surface (object side or image side) of the lens is aspherical, the lens may be said to have an aspherical surface profile. In one embodiment, both the object side and the image side of each lens can be designed to be aspheric. The aspheric design can help the optical system 10 to more effectively eliminate aberrations and improve imaging quality. In some embodiments, at least one lens of the optical system 10 may have a spherical surface shape, and the design of the spherical surface shape may reduce the difficulty of manufacturing the lens and reduce the manufacturing cost. In some embodiments, to achieve the desired combination of manufacturing cost, manufacturing difficulty, imaging quality, assembly difficulty, etc., the design of each lens surface in the optical system 10 may be composed of a combination of aspheric and spherical surface types. It should be noted that when the object side or image side of a lens is aspheric, the surface may have a curvature, and the type of surface from center to edge will change, for example, one lens surface is convex near the paraxial region 101 and concave near the maximum effective aperture.

The surface type calculation of the aspherical surface can refer to an aspherical surface formula:

where Z is the distance from the corresponding point on the aspheric surface to the tangential plane of the surface at the optical axis 101, r is the distance from the corresponding point on the aspheric surface to the optical axis 101, c is the curvature of the aspheric surface at the optical axis 101, k is the conic coefficient, ai is the higher order term coefficient corresponding to the i-th order higher order term in the aspheric surface formula.

On the other hand, in some embodiments, at least one lens of the optical system 10 is made of Plastic (Plastic), which may be polycarbonate, gum, or the like. In some embodiments, the material of at least one lens in the optical system 10 is Glass (Glass). The lens with plastic material can reduce the production cost of the optical system 10, while the lens with glass material can withstand higher or lower temperature and has excellent optical effect and better stability. In some embodiments, lenses of different materials may be disposed in the optical system 10, i.e. a combination of glass lenses and plastic lenses may be used, but the specific configuration relationship may be determined according to practical requirements, which is not meant to be exhaustive.

In a first specific embodiment of the present application, the optical system 10 of the first embodiment includes, in order from an object side to an image side along the optical axis 101: a first lens L1 having positive optical power, a second lens L2 having negative optical power, a third lens L3 having positive optical power, a fourth lens L4 having positive optical power, a fifth lens L5 having negative optical power, a sixth lens L6 having positive optical power, and a seventh lens L7 having negative optical power.

The object-side surface S1 of the first lens element L1 is convex at the paraxial region 101, the image-side surface S2 of the first lens element L1 is concave at the paraxial region 101, the object-side surface S3 of the second lens element L2 is convex at the paraxial region 101, the image-side surface S4 of the sixth lens element L6 is concave at the paraxial region 101, the image-side surface S5 of the third lens element L3 is convex at the paraxial region 101, the image-side surface S6 of the third lens element L3 is concave at the paraxial region 101, the object-side surface S8 of the fourth lens element L4 is concave at the paraxial region 101, the image-side surface S9 of the fourth lens element L4 is convex at the paraxial region 101, the object-side surface S10 of the fifth lens element L5 is concave at the paraxial region 101, the image-side surface S11 of the fifth lens element L5 is concave at the paraxial region 101, the object-side surface S12 of the sixth lens element L6 is convex at the paraxial region 101, the image-side surface S13 of the sixth lens element L6 is convex at the paraxial region 101, the object-side surface S14 of the seventh lens element L7 is concave at the paraxial region 101, and the image-side surface S15 at the paraxial region 101 is concave at the seventh lens element 7.

The optical system 10 in the first embodiment satisfies the conditions of table 1. The elements from the object side to the image side of the optical system 10 are sequentially arranged in the order from top to bottom of table 1, wherein the aperture stop STO characterizes the aperture stop. The filter 110 may be part of the optical system 10 or may be removable from the optical system 10, but the total optical length TTL of the optical system 10 remains unchanged when the filter 110 is removed. The filter 110 may be an infrared cut filter 110. The radius Y in table 1 is the radius of curvature of the corresponding surface of the lens at the optical axis 101. The first value of the lens in the "thickness" parameter row is the thickness of the lens on the optical axis 101, and the second value is the distance from the image side of the lens to the subsequent optical element (lens or stop STO) on the optical axis 101, wherein the thickness parameter of the stop STO represents the distance from the stop STO surface to the object side of the adjacent lens on the optical axis 101. The refractive index and Abbe number of each lens in the table are 587.56nm, the reference wavelength of focal length (effective focal length) is 587.56nm, and the numerical units of Y radius, thickness and focal length (effective focal length) are millimeter (mm). In addition, the parameter data and the lens surface type structure used for the relational computation in the following embodiments are based on the data in the lens parameter table in the corresponding embodiments.

In the following table, the surface number 1 and the surface number 2 are the object side surface S1 and the image side surface S2 of the first lens element L1, respectively, that is, in the same lens element, the surface with the smaller surface number is the object side surface, and the surface with the larger surface number is the image side surface, which will not be described herein. Meanwhile, the lenses in other embodiments of the present application are also shown here, and will not be described in detail below.

TABLE 1

Note that f is an effective focal length of the optical system 10, FNO is an f-number of the optical system 10, HFOV is a half of a maximum field angle of the optical system 10, and TTL is a distance between the object side surface S1 of the first lens L1 and the imaging surface S18 of the optical system 10 on the optical axis 101.

In this embodiment, the object side surfaces and the image side surfaces of the seven lenses are aspheric, and the conical constants K and the aspheric coefficients corresponding to the surfaces of the aspheric surfaces are shown in table 2:

TABLE 2

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Further, referring to fig. 2 (a), fig. 2 (a) shows a longitudinal spherical aberration diagram of the optical system 10 in the first embodiment at wavelengths 656.27nm,578.56nm,486.13 nm. In fig. 2 (a), the abscissa represents the focus offset, and the ordinate represents the normalized field of view. As can be seen from fig. 2 (a), the spherical aberration value of the optical system 10 in the first embodiment is better, which means that the imaging quality of the optical system 10 in the present embodiment is better.

Referring to fig. 2 (B), fig. 2 (B) is a light astigmatism diagram of the optical system 10 in the first embodiment at a wavelength of 578.56 nm. Wherein the abscissa represents focus offset, and the ordinate represents image height in mm. The astigmatic curve represents the meridional imaging plane curvature T and the sagittal imaging plane curvature S. As can be seen from fig. 2 (B), the astigmatism of the optical system 10 in the present embodiment is well compensated.

Referring to fig. 2 (C), fig. 2 (C) is a graph showing distortion of the optical system 10 at a wavelength of 578.56nm in the first embodiment. Wherein the abscissa represents distortion and the ordinate represents image height in mm. As can be seen from fig. 2 (C), the distortion of the optical system 10 in the present embodiment is well corrected at the wavelength 578.56 nm.

As can be seen from fig. 2 (a), 2 (B) and 2 (C), the optical system 10 in the present embodiment has small aberration, good imaging quality, and excellent imaging quality.

In a second embodiment of the present application, referring to fig. 3 to 4, an optical system 10 of the second embodiment includes, in order from an object side to an image side along an optical axis 101: a first lens L1 having positive optical power, a second lens L2 having negative optical power, a third lens L3 having positive optical power, a fourth lens L4 having positive optical power, a fifth lens L5 having negative optical power, a sixth lens L6 having positive optical power, and a seventh lens L7 having negative optical power.

The object-side surface S1 of the first lens element L1 is convex at the paraxial region 101, the image-side surface S2 of the first lens element L1 is concave at the paraxial region 101, the object-side surface S3 of the second lens element L2 is convex at the paraxial region 101, the image-side surface S4 of the sixth lens element L6 is concave at the paraxial region 101, the image-side surface S5 of the third lens element L3 is convex at the paraxial region 101, the image-side surface S6 of the third lens element L3 is concave at the paraxial region 101, the object-side surface S8 of the fourth lens element L4 is concave at the paraxial region 101, the image-side surface S9 of the fourth lens element L4 is convex at the paraxial region 101, the object-side surface S10 of the fifth lens element L5 is concave at the paraxial region 101, the image-side surface S11 of the fifth lens element L5 is concave at the paraxial region 101, the object-side surface S12 of the sixth lens element L6 is convex at the paraxial region 101, the image-side surface S13 of the sixth lens element L6 is concave at the paraxial region 101, the object-side surface S14 of the seventh lens element L7 is concave at the paraxial region 101, and the image-side surface S15 at the paraxial region 101 is concave at the seventh lens element L7.

The parameters of each lens of the optical system 10 in the second embodiment are given in tables 3 and 4, wherein the names and parameters of each element are defined in the first embodiment, and are not described herein.

TABLE 3 Table 3

In this embodiment, the object side surfaces and the image side surfaces of the seven lenses are aspheric, and the conical constants K and the aspheric coefficients corresponding to the surfaces of the aspheric surfaces are shown in table 4:

TABLE 4 Table 4

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In addition, as is clear from the aberration diagram in fig. 4, the longitudinal spherical aberration, curvature of field, and distortion of the optical system 10 are all well controlled, so that the optical system 10 of this embodiment has good imaging quality.

In a third embodiment of the present invention, referring to fig. 5 to 6, an optical system 10 of the third embodiment includes, in order from an object side to an image side along an optical axis 101: a first lens L1 having positive optical power, a second lens L2 having negative optical power, a third lens L3 having positive optical power, a fourth lens L4 having negative optical power, a fifth lens L5 having negative optical power, a sixth lens L6 having positive optical power, and a seventh lens L7 having negative optical power.

The object-side surface S1 of the first lens element L1 is convex at the paraxial region 101, the image-side surface S2 of the first lens element L1 is concave at the paraxial region 101, the object-side surface S3 of the second lens element L2 is convex at the paraxial region 101, the image-side surface S4 of the sixth lens element L6 is concave at the paraxial region 101, the image-side surface S5 of the third lens element L3 is convex at the paraxial region 101, the image-side surface S6 of the third lens element L3 is concave at the paraxial region 101, the object-side surface S8 of the fourth lens element L4 is convex at the paraxial region 101, the image-side surface S9 of the fourth lens element L4 is convex at the paraxial region 101, the object-side surface S10 of the fifth lens element L5 is concave at the paraxial region 101, the image-side surface S11 of the fifth lens element L5 is concave at the paraxial region 101, the object-side surface S12 of the sixth lens element L6 is convex at the paraxial region 101, the image-side surface S13 of the sixth lens element L6 is convex at the paraxial region 101, the object-side surface S14 of the seventh lens element L7 is concave at the paraxial region 101, and the image-side surface S15 at the paraxial region 101 is concave at the seventh lens element L7.

The parameters of each lens of the optical system 10 in the third embodiment are given in tables 5 and 6, wherein the names and parameters of each element are defined in the first embodiment, and are not described herein.

TABLE 5

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In this embodiment, the object side surfaces and the image side surfaces of the seven lenses are aspheric, and the conical constants K and the aspheric coefficients corresponding to the surfaces of the aspheric surfaces are shown in table 6:

TABLE 6

In addition, as is clear from the aberration diagram in fig. 6, the longitudinal spherical aberration, curvature of field, and distortion of the optical system 10 are all well controlled, so that the optical system 10 of this embodiment has good imaging quality.

In a fourth specific embodiment of the present application, referring to fig. 7 and 8, an optical system 10 of the fourth embodiment includes, in order from an object side to an image side along an optical axis 101: a first lens L1 having positive optical power, a second lens L2 having negative optical power, a third lens L3 having positive optical power, a fourth lens L4 having positive optical power, a fifth lens L5 having negative optical power, a sixth lens L6 having negative optical power, and a seventh lens L7 having positive optical power.

The parameters of each lens of the optical system 10 in the fourth embodiment are given in tables 7 and 8, wherein the names and parameters of each element are defined in the first embodiment, and the description thereof is omitted herein.

TABLE 7

In this embodiment, the object side surfaces and the image side surfaces of the seven lenses are aspheric, and the conical constants K and the aspheric coefficients corresponding to the surfaces of the aspheric surfaces are shown in table 8:

TABLE 8

In addition, as is clear from the aberration diagram in fig. 8, the longitudinal spherical aberration, curvature of field, and distortion of the optical system 10 are all well controlled, so that the optical system 10 of this embodiment has good imaging quality.

In a fifth specific embodiment of the present application, referring to fig. 9 and 10, an optical system 10 of the fifth embodiment includes, in order from an object side to an image side along an optical axis 101: a first lens L1 having positive optical power, a second lens L2 having negative optical power, a third lens L3 having positive optical power, a fourth lens L4 having positive optical power, a fifth lens L5 having negative optical power, a sixth lens L6 having positive optical power, and a seventh lens L7 having positive optical power.

The object-side surface S1 of the first lens element L1 is convex at the paraxial region 101, the image-side surface S2 of the first lens element L1 is convex at the paraxial region 101, the object-side surface S3 of the second lens element L2 is convex at the paraxial region 101, the image-side surface S4 of the sixth lens element L6 is concave at the paraxial region 101, the object-side surface S5 of the third lens element L3 is convex at the paraxial region 101, the image-side surface S6 of the third lens element L3 is convex at the paraxial region 101, the object-side surface S8 of the fourth lens element L4 is concave at the paraxial region 101, the image-side surface S9 of the fourth lens element L4 is convex at the paraxial region 101, the object-side surface S10 of the fifth lens element L5 is concave at the paraxial region 101, the object-side surface S12 of the sixth lens element L6 is convex at the paraxial region 101, the image-side surface S13 of the sixth lens element L6 is concave at the paraxial region 101, the object-side surface S14 of the seventh lens element L7 is concave at the paraxial region 101, and the image-side surface S15 at the paraxial region 101 is concave at the seventh lens element L7.

The lens parameters of the optical system 10 in the fifth embodiment are given in tables 9 and 10, wherein the definition of the names and parameters of the elements can be obtained in the first embodiment, and the details are not repeated here.

TABLE 9

In this embodiment, the object side surfaces and the image side surfaces of the seven lenses are aspheric, and the conical constants K and the aspheric coefficients corresponding to the surfaces of the aspheric surfaces are shown in table 10:

table 10

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In addition, as is clear from the aberration diagram in fig. 10, the longitudinal spherical aberration, curvature of field, and distortion of the optical system 10 are all well controlled, so that the optical system 10 of this embodiment has good imaging quality.

Referring to Table 11, table 11 shows the values of FNO TTL/Imgh, f tan (HFOV), (f1+|f2|)/f, (R10+R11)/(R10-R11), ALT/CT5, SD72/SD11, CT3/ET3, SAG62/SAG61, f5/f123 in the first to fifth embodiments of the present invention.

TABLE 11

	First embodiment	Second embodiment	Third embodiment	Fourth embodiment	Fifth embodiment
						FNO*TTL/IMGH	2.942	3.076	2.883	3.007	3.404
f*tan(HFOV)	4.129	4.258	3.994	4.343	4.094
						(f1+\|f2\|)/f	3.816	4.381	4.239	3.734	3.695
(R10+R11)/(R10-R11)	3.710	1.470	4.376	3.649	1.498
						ALT/CT5	10.987	12.795	11.687	12.065	13.039
SD72/SD11	4.180	4.315	4.083	4.172	4.492
						CT3/ET3	1.910	1.834	1.138	1.736	2.174
SAG62/SAG61	1.016	4.289	2.343	1.183	1.392
						f5/f123	-1.431	-1.658	-3.830	-2.299	-1.870

As can be seen from table 11, the optical system 10 in each of the first to sixth embodiments satisfies the following conditions: 2.8< FNO TTL/IMGH <3.5, 3.9< f tan (HFOV) <4.4, 3.5< (f1+|f2|)/f <4.5, 1.4< (R10+R11)/(R10-R11) <4.4, 10.5< ALT/CT5<13.5, 4< SD72/SD11<4.5, 1< CT3/ET3<2.5, 1< SAG62/SAG61<4.5, -4< f5/f123< -1.

As shown in fig. 11, the present invention further provides an image capturing module 100 having the optical system 10 of the above embodiment.

As shown in fig. 11, an image capturing module 100 according to an embodiment of the present invention includes an optical system 10 and a photosensitive element 20, the photosensitive element 20 being disposed on an image side of the optical system 10.

According to the image capturing module 100 of the embodiment of the present invention, by installing the first lens L1 to the seventh lens L7 of the optical system 10 in the lens module and reasonably configuring the surface type and the focal power of each lens of the first lens L1 to the seventh lens L7, the image capturing module 100 can meet the requirement of miniaturization, and the image capturing module 100 can obtain a larger imaging range.

As shown in fig. 12, the present invention also proposes an electronic device 1000 having the optical system 10 of the above embodiment.

As shown in fig. 12, the electronic device 1000 according to the embodiment of the invention includes a housing 200 and an image capturing module 100, wherein the image capturing module 100 is mounted on the housing 200. The electronic device may be a smart phone, a Personal Digital Assistant (PDA), a tablet computer, a smart watch, an unmanned aerial vehicle, an electronic book reader, a vehicle recorder, a wearable device, etc.

According to the electronic device 1000 of the embodiment of the invention, by arranging the image capturing module 100 in the housing 200, the electronic device 1000 can meet the requirement of miniaturization, and the electronic device 1000 can obtain a larger imaging range.

It will be evident to those skilled in the art that the present application is not limited to the details of the foregoing illustrative embodiments, and that the present application may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Finally, it should be noted that the above embodiments are merely for illustrating the technical solution of the present application and not for limiting, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present application may be modified or substituted without departing from the spirit and scope of the technical solution of the present application.

Claims

1. An optical system, characterized in that the number of lenses having optical power is seven, and sequentially comprises, from an object side to an image side along an optical axis:

a first lens having positive optical power; the object side surface of the lens is convex at a paraxial region;

a second lens having negative optical power; the object side surface is convex at the paraxial region, and the image side surface is concave at the paraxial region;

A third lens having positive optical power; the object side surface of the lens is convex at a paraxial region;

a fourth lens element with optical power, having a convex image-side surface at a paraxial region;

a fifth lens element with negative refractive power having a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region;

a sixth lens having optical power; the object side surface of the lens is convex at a paraxial region;

a seventh lens having optical power; the object side surface is convex at the paraxial region, and the image side surface is concave at the paraxial region;

wherein the optical system satisfies the following relation:

2.8<FNO*TTL/Imgh<3.5，4<SD72/SD11<4.5，

TTL is the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis, imgh is half of the image height corresponding to the maximum field angle of the optical system, and FNO is the f-number of the optical system; SD11 is half of the maximum aperture of the object side surface of the first lens element, and SD72 is half of the maximum aperture of the image side surface of the seventh lens element.

2. The optical system of claim 1, wherein the optical system satisfies the following relationship:

3.9<f*tan(HFOV)<4.4；

where f is the effective focal length of the optical system and HFOV is half the maximum field angle of the optical system.

3. The optical system of claim 1, wherein the optical system satisfies the following relationship:

3.5<(f1+|f2|)/f<4.5；

wherein f1 is the focal length of the first lens, f2 is the focal length of the second lens, and f is the effective focal length of the optical system.

4. The optical system of claim 1, wherein the optical system satisfies the following relationship:

1.4<(R10+R11)/(R10-R11)<4.4；

wherein R10 is a radius of curvature of the object side surface of the fifth lens element at the optical axis, and R11 is a radius of curvature of the image side surface of the fifth lens element at the optical axis.

5. The optical system of claim 1, wherein the optical system satisfies the following relationship:

10.5<ALT/CT5<13.5；

where ALT is the sum of the center thicknesses of the first lens to the seventh lens on the optical axis, and CT5 is the center thickness of the fifth lens on the optical axis.

6. The optical system of claim 1, wherein the optical system satisfies the following relationship:

1<CT3/ET3<2.5；

wherein CT3 is a distance between the object side surface of the third lens element and the image side surface of the third lens element on the optical axis, and ET3 is a distance between the maximum effective half-caliber of the object side surface of the third lens element and the maximum effective half-caliber of the image side surface of the third lens element along the optical axis.

7. The optical system of claim 1, wherein the optical system satisfies the following relationship:

1<SAG62/SAG61<4.5；

wherein SAG62 is a distance between an intersection point of the image side surface of the sixth lens and the optical axis and a maximum effective caliber of the image side surface of the sixth lens on the optical axis, and SAG61 is a distance between an intersection point of the object side surface of the sixth lens and the optical axis and a maximum effective caliber of the object side surface of the sixth lens on the optical axis.

8. The optical system of claim 1, wherein the optical system satisfies the following relationship:

-4<f5/f123<-1；

wherein f5 is a focal length of the fifth lens, and f123 is a combined focal length of the first lens, the second lens, and the third lens.

9. An image capturing module, wherein the image capturing module comprises:

the optical system of any one of claims 1 to 8;

and the photosensitive element is arranged on the image side of the optical system.

10. An electronic device, the electronic device comprising:

a housing;

the imaging module of claim 9, the imaging module mounted on the housing.