CN212540842U

CN212540842U - Optical system, image capturing module and electronic equipment

Info

Publication number: CN212540842U
Application number: CN202021194878.0U
Authority: CN
Inventors: 谭怡翔; 刘秀; 李明
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2020-06-24
Filing date: 2020-06-24
Publication date: 2021-02-12
Anticipated expiration: 2030-06-24

Abstract

The utility model relates to an optical system, get for instance module and electronic equipment. The optical system includes in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface at paraxial region; a second lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a third lens element with refractive power; a fourth lens element with refractive power; a fifth lens element with refractive power; a sixth lens element with refractive power; a seventh lens element with refractive power having a concave object-side surface at paraxial region; the optical system satisfies the conditional expression: f 43/(ImgH FNO) < 25; f is the effective focal length of the optical system, ImgH is half of the diagonal length of the effective pixel area of the optical system on the imaging plane, and FNO is the f-number of the optical system. The optical system can have excellent imaging quality even when imaging a long-distance subject or in a dark environment.

Description

Optical system, image capturing module and electronic equipment

Technical Field

The utility model relates to a field of making a video recording especially relates to an optical system, gets for instance module and electronic equipment.

Background

With the rapid popularization of electronic devices with a camera shooting function, such as smart phones and tablet computers, the requirements of users on the camera shooting performance of the electronic devices are higher and higher, and particularly, the electronic devices can have excellent imaging quality in an environment with insufficient light, so that the requirements of high imaging quality in different environments can be met. However, the brightness of the image shot by the conventional electronic device in the environment with insufficient light is low, the image is not clear enough, and the requirement of high imaging quality is difficult to meet.

SUMMERY OF THE UTILITY MODEL

Therefore, it is necessary to provide an optical system, an image capturing module and an electronic device for solving the problems that the current electronic device cannot clearly image in a dark environment and cannot meet the requirement of high imaging quality.

An optical system comprising, in order from an object side to an image side:

a first lens element with positive refractive power having a convex object-side surface at paraxial region;

a second lens element with negative refractive power having a convex object-side surface and a concave image-side surface;

a third lens element with refractive power;

a fourth lens element with refractive power;

a fifth lens element with refractive power;

a sixth lens element with refractive power;

a seventh lens element with refractive power having a concave object-side surface at paraxial region;

and the optical system satisfies the following conditional expression:

f*43/(ImgH*FNO)＜25；

wherein f is the effective focal length of the optical system, ImgH is the diagonal length of the effective pixel area of the optical system on the imaging plane, and FNO is the f-number of the optical system.

The above conditional expression is an equivalent focal length calculated by the optical system with reference to a full frame, and an optical system with an equivalent focal length of more than 50mm generally has a certain telephoto performance. When the condition formula is met, the amplification capacity of the optical system is more than twice of that of an optical system with an equivalent focal length of 25mm, and the numerical value of ImgH is larger, so that the optical system can adapt to photosensitive elements with larger sizes and higher pixels, and the imaging definition of the optical system is further improved. And when the above conditional expressions are satisfied, the effective focal length of the optical system, the diagonal length of the effective pixel region on the imaging surface and the f-number can be reasonably configured, so that the optical system has a larger magnification, and further the system can realize a short-distance shooting effect on a long-distance shot object.

In one embodiment, the optical system satisfies the following conditional expression:

1.9≤(|R32|+|R42|)/f≤7.2；

wherein R32 is a curvature radius of the image-side surface of the third lens element on the optical axis, and R42 is a curvature radius of the image-side surface of the fourth lens element on the optical axis. The third lens element provides positive or negative refractive power for the optical system, the fourth lens element provides positive or negative refractive power for the optical system, and the combination of the third lens element and the fourth lens element can better correct distortion and coma generated by each lens element at the object side of the third lens element. When the conditional expressions are met, the curvature radii of the image side surfaces of the third lens and the fourth lens at the optical axis and the effective focal length of the optical system can be reasonably configured, so that the situation that the surface types of the image side surfaces of the third lens and the fourth lens are too curved or too gentle to generate larger spherical aberration or vertical axis chromatic aberration on the optical system is avoided, reasonable distribution of primary aberration in each lens of the optical system is facilitated, and tolerance sensitivity of the optical system is reduced.

5≤(|f2|+|f3|)/R31≤22；

wherein f2 is an effective focal length of the second lens, f3 is an effective focal length of the third lens, and R31 is a radius of curvature of an object-side surface of the third lens at an optical axis. The second lens element provides negative refractive power for the optical system, and the third lens element provides positive or negative refractive power for the optical system, so that when the above conditional expressions are satisfied, the second lens element and the third lens element can integrally counteract the primary aberration generated by the first lens element; meanwhile, the effective focal lengths of the second lens and the third lens and the curvature radius of the object side surface of the third lens at the paraxial position can be reasonably configured, so that the second lens and the third lens are prevented from generating larger spherical aberration and vertical axis chromatic aberration on the optical system, the reasonable distribution of primary aberration in each lens of the optical system is facilitated, and the tolerance sensitivity of the optical system is reduced.

f/f1≤2；

wherein f1 is the effective focal length of the first lens. When the condition is met, the effective focal length of the first lens and the effective focal length of the optical system can be reasonably configured, so that the refractive power borne by the first lens in the optical system is moderate, the generation of chromatic aberration and spherical aberration is effectively reduced, the imaging quality of the optical system is further improved, and the reduction of the sensitivity of the optical system is facilitated. At the same time, the optical system can be provided with telephoto characteristics while maintaining a compact design of the optical system.

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

|R41/R51|≤1；

wherein R41 is a radius of curvature of an object-side surface of the fourth lens element at an optical axis, and R51 is a radius of curvature of an object-side surface of the fifth lens element at the optical axis. When the conditional expressions are satisfied, the numerical values of R41 and R51 can be reasonably configured to ensure that the object-side surface of the fourth lens element and the object-side surface of the fifth lens element can reasonably distribute refractive power in the vertical direction, so that aberration of the optical system is suppressed, and reduction of the size of a dispersed spot in the optical system is facilitated.

f≥7.2mm；

TTL≤7mm；

TTL/f≤1.0；

wherein, TTL is a distance on an optical axis from an object-side surface of the first lens element to an image plane of the optical system. The conditional expression is satisfied: when f is larger than or equal to 7.2mm, the optical system is matched with the photosensitive element to have long focal length. And when the condition expression is satisfied, the optical system can have a long focal length under the condition that TTL is less than or equal to 7mm, and the optical system is favorably installed in the miniaturized electronic equipment. In addition, when the conditional expressions are satisfied, the aberration such as chromatic aberration, spherical aberration and distortion of the optical system can be corrected, and the imaging quality of the optical system can be improved.

4≤(|f1|+|f2|+|f3|)/f≤27；

wherein f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, and f3 is the effective focal length of the third lens. The first lens, the second lens and the third lens form a front lens group of the optical system, when the condition is met, the first lens, the second lens, the third lens and the effective focal length of the optical system can be reasonably configured to avoid the fact that the front lens group generates large aberration, the imaging quality of the optical system is improved, meanwhile, the size of the front lens group in the optical axis direction is favorably shortened, the total length of the optical system is favorably shortened, and the miniaturization design is achieved.

6≤TTL/(CT23+CT45)≤8.3；

wherein, TTL is an axial distance from an object-side surface of the first lens element to an image plane of the optical system, CT23 is an axial distance from an image-side surface of the second lens element to an object-side surface of the third lens element, and CT45 is an axial distance from an image-side surface of the fourth lens element to an object-side surface of the fifth lens element. When the above conditional expressions are satisfied, the arrangement between the third lens element and the fourth lens element can be made more compact, and the third lens element and the fourth lens element become transition portions of light deflection in the optical system, even if the refractive power of the third lens element and the fourth lens element in the optical system is small, the sensitivity of the optical system to the distance between the third lens element and the fourth lens element is reduced.

-0.5≤|R41|/f4≤0.2；

wherein R41 is a radius of curvature of an object-side surface of the fourth lens at an optical axis, and f4 is an effective focal length of the fourth lens. When the conditional expressions are satisfied, the curvature radius of the object side surface of the fourth lens at the optical axis and the effective focal length of the fourth lens can be reasonably configured, so that the surface type complexity of the fourth lens is reduced, and further the distortion of the optical system and the generation of field curvature in the meridian direction are favorably inhibited, so that the imaging quality of the optical system is improved, and the forming difficulty of the fourth lens is favorably reduced.

An image capturing module includes a photosensitive element and the optical system of any of the above embodiments, wherein the photosensitive element is disposed at an image side of the optical system. The optical system is adopted in the image capturing module, so that the amplifying capacity of the image capturing module can be enhanced, the optical system can adapt to the photosensitive elements with larger sizes and higher pixels, and the imaging quality of the optical system is improved. In addition, the image capturing module can have excellent imaging quality when imaging a long-distance shot object, and meanwhile, the imaging quality of the image capturing module in a dark environment can be improved.

An electronic device comprises a shell and the image capturing module, wherein the image capturing module is arranged on the shell. The image capturing module is adopted in the electronic equipment, and the imaging quality of the electronic equipment can be improved by enhancing the amplifying capacity of the optical system. In addition, when the electronic equipment images a long-distance shot object, the electronic equipment can have excellent imaging quality, and meanwhile, the imaging quality of the electronic equipment in a dark environment can be improved.

Drawings

FIG. 1 is a schematic view of an optical system in a first embodiment of the present application;

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

FIG. 3 is a schematic view of an optical system in a second embodiment of the present application;

FIG. 4 is a spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system in a second embodiment of the present application;

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

FIG. 6 is a spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system in a third embodiment of the present application;

FIG. 7 is a schematic view of an optical system according to a fourth embodiment of the present application;

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

FIG. 9 is a schematic view of an optical system in a fifth embodiment of the present application;

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

fig. 11 is a schematic view of an image capturing module according to an embodiment of the present application;

fig. 12 is a schematic diagram of an electronic device in an embodiment of the present application.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will be able to make similar modifications without departing from the spirit and scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present application, unless expressly stated or limited otherwise, the first feature may be directly on or directly under the second feature or indirectly via intermediate members. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

In some embodiments of the present disclosure, referring to fig. 1, the optical system 100 includes, in order from an object side to an image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7. Specifically, the first lens L1 includes an object-side surface S1 and an image-side surface S2, the second lens L2 includes an object-side surface S3 and an image-side surface S4, the third lens L3 includes an object-side surface S5 and an image-side surface S6, the fourth lens L4 includes an object-side surface S7 and an image-side surface S8, the fifth lens L5 includes an object-side surface S9 and an image-side surface S10, the sixth lens L6 includes an object-side surface S11 and an image-side surface S12, and the seventh lens L7 includes an object-side surface S13 and an image-side surface S14.

The first lens element L1 with positive refractive power helps to shorten the total length of the optical system 100, and the object-side surface S1 of the first lens element L1 is convex at the paraxial region, so that the positive refractive power of the first lens element L1 can be further enhanced, the size of the optical system 100 in the optical axis direction can be further shortened, and the optical system 100 can be miniaturized. The second lens element L2 with negative refractive power has a convex object-side surface S3 and a concave image-side surface S4 at paraxial regions of the second lens element L2. The third lens element L3, the fourth lens element L4, the fifth lens element L5 and the sixth lens element L6 all have refractive power. The seventh lens element L7 with refractive power has a concave object-side surface S13 at the paraxial region of the seventh lens element L7.

In addition, in some embodiments, the optical system 100 is provided with a stop STO, which may be disposed on the object side of the first lens L1. In some embodiments, the optical system 100 further includes an infrared filter L8 disposed on the image side of the seventh lens L7, and the infrared filter L8 includes an object-side surface S15 and an image-side surface S16. Furthermore, the optical system 100 further includes an image plane S17 located on the image side of the seventh lens L7, the image plane S17 is an imaging plane of the optical system 100, and incident light is adjusted by the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 and can be imaged on the image plane S17. It should be noted that the infrared filter L8 may be an infrared cut filter, and is used for filtering the interference light and preventing the interference light from reaching the image plane S17 of the optical system 100 to affect the normal imaging.

In some embodiments, the object-side surface and the image-side surface of each lens of optical system 100 are both aspheric. The adoption of the aspheric surface structure can improve the flexibility of lens design, effectively correct spherical aberration and improve imaging quality. In other embodiments, the object-side surface and the image-side surface of each lens of the optical system 100 may be spherical. It should be noted that the above embodiments are only examples of some embodiments of the present application, and in some embodiments, the surface of each lens in the optical system 100 may be an aspheric surface or any combination of spherical surfaces.

In some embodiments, each lens in the optical system 100 may be made of glass or plastic. The lens made of plastic material can reduce the weight of the optical system 100 and the production cost, and the small size of the optical system is matched to realize the light and small design of the optical system. The glass lens provides the optical system 100 with excellent optical performance and high temperature resistance. It should be noted that the material of each lens in the optical system 100 may be any combination of glass and plastic, and is not necessarily both glass and plastic.

It is to be noted that the first lens L1 does not mean that there is only one lens, and in some embodiments, there may be two or more lenses in the first lens L1, and the two or more lenses can form a cemented lens, and a surface of the cemented lens closest to the object side can be regarded as the object side surface S1, and a surface of the cemented lens closest to the image side can be regarded as the image side surface S2. Alternatively, although no cemented lens is formed between the lenses of the first lens L1, the distance between the lenses is relatively fixed, and in this case, the object-side surface of the lens closest to the object side is the object-side surface S1, and the image-side surface of the lens closest to the image side is the image-side surface S2. In addition, the number of lenses in the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 or the seventh lens L7 in some embodiments may be greater than or equal to two, and a cemented lens may be formed between any two adjacent lenses, or a non-cemented lens may be used.

Further, in some embodiments, the optical system 100 satisfies the conditional expression: f 43/(ImgH FNO) < 25; where f is the effective focal length of the optical system 100, ImgH is the diagonal length of the effective pixel area of the optical system 100 on the image plane, and FNO is the f-number of the optical system 100. Specifically, f × 43/ImgH/FNO may be: 20.170, 20.325, 20.784, 21.369, 21.536, 22.824, 23.001, 23.520, 23.971, or 24.204. The above conditional expression is an equivalent focal length calculated by the optical system 100 based on a full frame, and the optical system 100 having an equivalent focal length of more than 50mm generally has a certain telephoto performance. When the above conditional expressions are satisfied, the magnification capability of the optical system 100 is greater than twice the magnification capability of the optical system 100 with an equivalent focal length of 25mm, and the value of ImgH is large, so that the optical system 100 can adapt to a photosensitive element with a larger size and a higher pixel, and further the imaging definition of the optical system 100 is improved. Moreover, when the above conditional expressions are satisfied, the effective focal length of the optical system 100, the diagonal length of the effective pixel region on the imaging plane, and the f-number can be reasonably configured, so that the optical system 100 has a larger magnification, and further the system can achieve a close-range shooting effect on a long-distance object, and in addition, compared with a general system with the same magnification, the optical system 100 has a larger aperture, so as to improve the luminous flux of the optical system 100, and the optical system 100 can also have excellent imaging quality in an environment with insufficient light.

In some embodiments, the optical system 100 satisfies the conditional expression: 1.9 is less than or equal to (| R32| + | R42|)/f is less than or equal to 7.2; wherein R32 is the radius of curvature of the image-side surface S6 of the third lens L3 at the optical axis, and R42 is the radius of curvature of the image-side surface S8 of the fourth lens L4 at the optical axis. Specifically, (| R32| + | R42|)/f may be: 1.997, 2.203, 2.869, 3.552, 4.451, 5.637, 6.114, 6.502, 6.985, or 7.108. The third lens element L3 provides positive or negative refractive power for the optical system 100, the fourth lens element L4 provides positive or negative refractive power for the optical system 100, and the combination of the third lens element L3 and the fourth lens element L4 can better correct the distortion and coma aberration generated by the lens elements on the object side of the third lens element L3. When the above conditional expressions are satisfied, the curvature radii of the image-side surfaces S6 of the third lens L3 and S8 of the fourth lens L4 at the optical axis and the effective focal length of the optical system 100 can be reasonably configured, so as to avoid that the surface types of the image-side surfaces of the third lens L3 and the fourth lens L4 are too curved or too gentle, which causes a large spherical aberration or vertical chromatic aberration to the optical system 100, and further, the reasonable distribution of the primary aberration among the lenses of the optical system 100 is facilitated, and the tolerance sensitivity of the optical system 100 is reduced.

In some embodiments, the optical system 100 satisfies the conditional expression: 5 to 22 (| f2| + | f3 |)/R31; where f2 is the effective focal length of the second lens L2, f3 is the effective focal length of the third lens L3, and R31 is the radius of curvature of the object-side surface S5 of the third lens L3 at the optical axis. Specifically, (| f2| + | f3|)/R31 may be: 5.625, 7.103, 8.564, 10.228, 12.514, 15.745, 16.268, 18.034, 20.551, or 21.145. When the second lens element L2 provides negative refractive power for the optical system 100 and the third lens element L3 provides positive or negative refractive power for the optical system 100, and the above conditional expressions are satisfied, the second lens element L2 and the third lens element L3 can counteract the primary aberration generated by the first lens element L1 as a whole; meanwhile, the effective focal lengths of the second lens L2 and the third lens L3 and the curvature radius of the object-side surface S5 of the third lens L3 at the paraxial position can be reasonably configured, so that the second lens L2 and the third lens L3 are prevented from generating large spherical aberration and vertical chromatic aberration on the optical system 100, the reasonable distribution of the primary aberration in each lens of the optical system 100 is facilitated, and the tolerance sensitivity of the optical system 100 is reduced.

In some embodiments, the optical system 100 satisfies the conditional expression: f/f1 is less than or equal to 2; where f1 is the effective focal length of the first lens L1. Specifically, f/f1 may be: 1.869, 1.872, 1.895, 1.910, 1.934, 1.955, 1.963, 1.975, 1.982, or 1.998. When the above conditional expressions are satisfied, the effective focal length of the first lens element L1 and the effective focal length of the optical system 100 can be reasonably configured, so that the refractive power of the first lens element L1 in the optical system 100 is moderate, thereby effectively reducing the generation of chromatic aberration and spherical aberration, improving the imaging quality of the optical system 100, and being beneficial to reducing the sensitivity of the optical system 100. At the same time, the optical system 100 can be provided with telephoto characteristics while maintaining the compact design of the optical system 100.

In some embodiments, the fourth lens element L4 has positive refractive power, at least one of the object-side surface S9 or the image-side surface S10 of the fifth lens element L5 has an inflection point, and the optical system 100 satisfies the following conditional expression: i R41/R51I is less than or equal to 1; wherein R41 is the radius of curvature of the object-side surface S9 of the fourth lens L4 at the optical axis, and R51 is the radius of curvature of the object-side surface S9 of the fifth lens L5 at the optical axis. Specifically, | R41/R51| may be: 0.176, 0.255, 0.364, 0.482, 0.512, 0.637, 0.702, 0.854, 0.906, or 0.963. When the above conditional expressions are satisfied, the values of R41 and R51 can be reasonably configured to ensure that the object-side surface S7 of the fourth lens element L4 and the object-side surface S9 of the fifth lens element L5 can reasonably distribute the refractive power in the vertical direction, so as to suppress the aberration of the optical system 100 and reduce the size of the speckle in the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: f is more than or equal to 7.2 mm; TTL is less than or equal to 7 mm; TTL/f is less than or equal to 1.0; wherein, TTL is an axial distance from the object-side surface S1 of the first lens element L1 to the image plane of the optical system 100, i.e., a total system length of the optical system 100. Specifically, f may be: 7.205 mm. TTL may be: 6.6, 6.7, 6.8, 6.9 or 7, data units are mm. TTL/f can be: 0.916, 0.925, 0.937, 0.941, 0.946, 0.950, 0.958, 0.963, 0.969, or 0.972. The conditional expression is satisfied: when f is larger than or equal to 7.2mm, the optical system 100 is beneficial to being matched with the photosensitive element to have long focal length characteristic. When the above conditional expression is satisfied, the optical system 100 can have a long focal length when TTL is less than or equal to 7mm, which is advantageous for mounting the optical system 100 in a miniaturized electronic device. In addition, when the above conditional expressions are satisfied, it is beneficial to correct aberrations such as chromatic aberration, spherical aberration, distortion, and the like of the optical system 100, and improve the imaging quality of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: less than or equal to 4 (| f1| + | f2| + | f3|)/f is less than or equal to 27; wherein f1 is the effective focal length of the first lens L1, f2 is the effective focal length of the second lens L2, and f3 is the effective focal length of the third lens L3. Specifically, (| f1| + | f2| + | f3|)/f may be: 4.460, 7.564, 9.332, 11.258, 14.751, 19.325, 20.834, 22.364, 24.683, or 26.836. The first lens L1, the second lens L2, and the third lens L3 form a front lens group of the optical system 100, and when the above conditional expressions are satisfied, the effective focal lengths of the first lens L1, the second lens L2, the third lens L3, and the optical system 100 can be reasonably configured, so as to avoid the front lens group from generating large aberration, thereby improving the imaging quality of the optical system 100, and simultaneously, the size of the front lens group in the optical axis direction can be favorably shortened, thereby being favorable for shortening the total length of the optical system 100, and realizing the miniaturization design.

In some embodiments, the optical system 100 satisfies the conditional expression: TTL/(CT23+ CT45) is more than or equal to 6 and less than or equal to 8.3; wherein, TTL is an axial distance from the object-side surface S1 of the first lens element L1 to the image plane of the optical system 100, CT23 is an axial distance from the image-side surface S4 of the second lens element L2 to the object-side surface S5 of the third lens element L3, and CT45 is an axial distance from the image-side surface S8 of the fourth lens element L4 to the object-side surface S9 of the fifth lens element L5. Specifically, TTL/(CT23+ CT45) may be: 6.190, 6.325, 6.714, 6.955, 7.210, 7.523, 7.687, 7.924, 8.034 or 8.252. When the above conditional expressions are satisfied, the arrangement between the third lens element L3 and the fourth lens element L4 can be made more compact, and the third lens element L3 and the fourth lens element L4 can be transition portions of the optical system 100 for light ray deflection, so that the sensitivity of the optical system 100 to the pitch between the third lens element L4 and the fourth lens element L4 can be reduced even if the refractive power of the third lens element L3 and the fourth lens element L4 in the optical system 100 is small.

In some embodiments, the optical system 100 satisfies the conditional expression: r41/f 4 is more than or equal to minus 0.5 and less than or equal to 0.2; wherein R41 is the radius of curvature of the object-side surface S7 of the fourth lens L4 at the optical axis, and f4 is the effective focal length of the fourth lens L4. Specifically, | R41|/f4 may be: -0.195, -0.162, -0.124, -0.065, -0.013, 0.025, 0.078, 0.135, 0.184 or 0.205. When the conditional expressions are satisfied, the curvature radius of the object-side surface S7 of the fourth lens L4 at the optical axis and the effective focal length of the fourth lens L4 can be reasonably configured, so that the surface complexity of the fourth lens L4 is reduced, and further, the distortion of the optical system 100 and the generation of field curvature in the meridional direction are favorably suppressed, so as to improve the imaging quality of the optical system 100, and simultaneously, the difficulty in molding the fourth lens L4 is favorably reduced.

Based on the above description of the embodiments, more specific embodiments and drawings are set forth below for detailed description.

First embodiment

Referring to fig. 1 and fig. 2, fig. 1 is a schematic diagram of the optical system 100 in the first embodiment, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, a sixth lens element L6 with positive refractive power, and a seventh lens element L7 with negative refractive power. Fig. 2 is a graph of the spherical aberration, astigmatism and distortion of the optical system 100 in the first embodiment, which is sequentially from left to right, wherein the reference wavelength of the astigmatism graph and the distortion graph is 587.5618nm, and the other embodiments are the same.

The object-side surface S1 of the first lens element L1 is convex paraxially, and the image-side surface S2 is convex paraxially;

the object-side surface S3 of the second lens element L2 is convex at the paraxial region, and the image-side surface S4 is concave at the paraxial region;

the object-side surface S5 of the third lens element L3 is convex paraxially, and the image-side surface S6 is concave paraxially;

the object-side surface S7 of the fourth lens element L4 is concave at the paraxial region thereof, and the image-side surface S8 is convex at the paraxial region thereof;

the object-side surface S9 of the fifth lens element L5 is concave at the paraxial region thereof, and the image-side surface S10 is convex at the paraxial region thereof;

the object-side surface S11 of the sixth lens element L6 is concave and the image-side surface S12 is convex;

the object-side surface S13 of the seventh lens element L7 is concave at the paraxial region, and the image-side surface S14 is concave at the paraxial region.

The object-side surface and the image-side surface of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are aspheric.

It should be noted that, in the present application, when a surface of a lens is described as being convex at a paraxial region (a central region of the side surface), it is understood that a region of the surface of the lens near an optical axis is convex.

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

Further, the optical system 100 satisfies the conditional expression: f 43/(ImgH FNO) 20.170; where f is the effective focal length of the optical system 100, ImgH is the diagonal length of the effective pixel area of the optical system 100 on the image plane, and FNO is the f-number of the optical system 100. The above conditional expression is an equivalent focal length calculated by the optical system 100 based on a full frame, and the optical system 100 having an equivalent focal length of more than 25mm generally has a certain telephoto performance. When the above conditional expressions are satisfied, the magnification capability of the optical system 100 is greater than twice the magnification capability of the optical system 100 with an equivalent focal length of 50mm, and the value of ImgH is large, so that the optical system 100 can adapt to a photosensitive element with a larger size and a higher pixel, and further the imaging definition of the optical system 100 is improved. Moreover, when the above conditional expressions are satisfied, the effective focal length of the optical system 100, the diagonal length of the effective pixel region on the imaging plane, and the f-number can be reasonably configured, so that the optical system 100 has a larger magnification, and further the system can achieve a close-range shooting effect on a long-distance object, and in addition, compared with a general system with the same magnification, the optical system 100 has a larger aperture, so as to improve the luminous flux of the optical system 100, and the optical system 100 can also have excellent imaging quality in an environment with insufficient light.

The optical system 100 satisfies the conditional expression: (| R32| + | R42|)/f ═ 2.879; wherein R32 is the radius of curvature of the image-side surface S6 of the third lens L3 at the optical axis, and R42 is the radius of curvature of the image-side surface S8 of the fourth lens L4 at the optical axis. The third lens element L3 provides positive or negative refractive power for the optical system 100, the fourth lens element L4 provides positive or negative refractive power for the optical system 100, and the combination of the third lens element L3 and the fourth lens element L4 can better correct the distortion and coma aberration generated by the lens elements on the object side of the third lens element L3. When the above conditional expressions are satisfied, the curvature radii of the image-side surfaces S6 of the third lens L3 and S8 of the fourth lens L4 at the optical axis and the effective focal length of the optical system 100 can be reasonably configured, so as to avoid that the surface types of the image-side surfaces of the third lens L3 and the fourth lens L4 are too curved or too gentle, which causes a large spherical aberration or vertical chromatic aberration to the optical system 100, and further, the reasonable distribution of the primary aberration among the lenses of the optical system 100 is facilitated, and the tolerance sensitivity of the optical system 100 is reduced.

The optical system 100 satisfies the conditional expression: (| f2| + | f3|)/R31 ═ 16.539; where f2 is the effective focal length of the second lens L2, f3 is the effective focal length of the third lens L3, and R31 is the radius of curvature of the object-side surface S5 of the third lens L3 at the optical axis. When the second lens element L2 provides negative refractive power for the optical system 100 and the third lens element L3 provides positive or negative refractive power for the optical system 100, and the above conditional expressions are satisfied, the second lens element L2 and the third lens element L3 can counteract the primary aberration generated by the first lens element L1 as a whole; meanwhile, the effective focal lengths of the second lens L2 and the third lens L3 and the curvature radius of the object-side surface S5 of the third lens L3 at the paraxial position can be reasonably configured, so that the second lens L2 and the third lens L3 are prevented from generating large spherical aberration and vertical chromatic aberration on the optical system 100, the reasonable distribution of the primary aberration in each lens of the optical system 100 is facilitated, and the tolerance sensitivity of the optical system 100 is reduced.

The optical system 100 satisfies the conditional expression: f/f1 is 1.960; where f1 is the effective focal length of the first lens L1. When the above conditional expressions are satisfied, the effective focal length of the first lens element L1 and the effective focal length of the optical system 100 can be reasonably configured, so that the refractive power of the first lens element L1 in the optical system 100 is moderate, thereby effectively reducing the generation of chromatic aberration and spherical aberration, improving the imaging quality of the optical system 100, and being beneficial to reducing the sensitivity of the optical system 100. At the same time, the optical system 100 can be provided with telephoto characteristics while maintaining the compact design of the optical system 100.

The optical system 100 satisfies the conditional expression: 0.176 | R41/R51 |; wherein R41 is the radius of curvature of the object-side surface S9 of the fourth lens L4 at the optical axis, and R51 is the radius of curvature of the object-side surface S9 of the fifth lens L5 at the optical axis. When the above conditional expressions are satisfied, the values of R41 and R51 can be reasonably configured to ensure that the object-side surface S7 of the fourth lens element L4 and the object-side surface S9 of the fifth lens element L5 can reasonably distribute the refractive power in the vertical direction, so as to suppress the aberration of the optical system 100 and reduce the size of the speckle in the optical system 100.

The optical system 100 satisfies the conditional expression: f is 7.205 mm; TTL is 7 mm; TTL/f is 0.972; wherein, TTL is an axial distance from the object-side surface S1 of the first lens element L1 to the image plane of the optical system 100, i.e., a total system length of the optical system 100. The conditional expression is satisfied: when f is larger than or equal to 7.2mm, the optical system 100 is beneficial to being matched with the photosensitive element to have long focal length characteristic. When the above conditional expression is satisfied, the optical system 100 can have a long focal length when TTL is less than or equal to 7mm, which is advantageous for mounting the optical system 100 in a miniaturized electronic device. In addition, when the above conditional expressions are satisfied, it is beneficial to correct aberrations such as chromatic aberration, spherical aberration, distortion, and the like of the optical system 100, and improve the imaging quality of the optical system 100.

The optical system 100 satisfies the conditional expression: (| f1| + | f2| + | f3|)/f 17.499; wherein f1 is the effective focal length of the first lens L1, f2 is the effective focal length of the second lens L2, and f3 is the effective focal length of the third lens L3. The first lens L1, the second lens L2, and the third lens L3 form a front lens group of the optical system 100, and when the above conditional expressions are satisfied, the effective focal lengths of the first lens L1, the second lens L2, the third lens L3, and the optical system 100 can be reasonably configured, so as to avoid the front lens group from generating large aberration, thereby improving the imaging quality of the optical system 100, and simultaneously, the size of the front lens group in the optical axis direction can be favorably shortened, thereby being favorable for shortening the total length of the optical system 100, and realizing the miniaturization design.

The optical system 100 satisfies the conditional expression: TTL/(CT23+ CT45) ═ 8.252; wherein, TTL is an axial distance from the object-side surface S1 of the first lens element L1 to the image plane of the optical system 100, CT23 is an axial distance from the image-side surface S4 of the second lens element L2 to the object-side surface S5 of the third lens element L3, and CT45 is an axial distance from the image-side surface S8 of the fourth lens element L4 to the object-side surface S9 of the fifth lens element L5. When the above conditional expressions are satisfied, the arrangement between the third lens L3 and the fourth lens L4 can be made more compact, and the third lens L3 and the fourth lens L4 can be made transition portions of light ray deflection in the optical system 100, so that the sensitivity of the optical system 100 to the pitch between the third lens L3 and the fourth lens L4 can be reduced even if the refractive power of the third lens L3 and the fourth lens L4 in the optical system 100 is small.

The optical system 100 satisfies the conditional expression: -0.142 | R41|/f 4; wherein R41 is the radius of curvature of the object-side surface S7 of the fourth lens L4 at the optical axis, and f4 is the effective focal length of the fourth lens L4. When the above conditional expressions are satisfied, the curvature radius of the object-side surface S7 of the fourth lens element L4 at the optical axis and the effective focal length of the fourth lens element L4 can be reasonably configured, so that the surface complexity of the fourth lens element L4 is reduced, which is further beneficial to suppressing the distortion of the optical system 100 and the generation of field curvature in the T direction in the meridional direction, so as to improve the imaging quality of the optical system 100, and simultaneously, is beneficial to reducing the molding difficulty of the fourth lens element L4.

In addition, the parameters of the optical system 100 are given in table 1. Among them, the image plane S17 in table 1 may be understood as an imaging plane of the optical system 100. The elements from the object plane (not shown) to the image plane S17 are sequentially arranged in the order of the elements from top to bottom in table 1. The Y radius in table 1 is the radius of curvature of the object-side surface or the image-side surface of the corresponding surface number at the optical axis. Surface number 1 and surface number 2 are the object-side surface S1 and the image-side surface S2 of the first lens L1, respectively, that is, in the same lens, 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. The first numerical value in the "thickness" parameter column of the first lens element L1 is the axial thickness of the lens element, and the second numerical value is the axial distance from the image-side surface of the lens element to the object-side surface of the following lens element in the image-side direction.

Note that, in this embodiment and the following embodiments, the optical system 100 may not be provided with the infrared filter L8, but the distance from the image-side surface S14 of the seventh lens L7 to the image surface S17 is kept constant at this time.

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

And the focal length, refractive index and Abbe number of each lens are values at d-line (587.56nm), and the same applies to other embodiments.

TABLE 1

Further, aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are given by table 2. In which the surface numbers 1-14 represent image side surfaces or object side surfaces S1-S14, respectively. And K-a20 from top to bottom respectively indicate the types of aspheric coefficients, where K indicates a conic coefficient, a4 indicates a quartic aspheric coefficient, a6 indicates a sextic aspheric coefficient, A8 indicates an octal aspheric coefficient, and so on. In addition, the aspherical surface coefficient formula is as follows:

z is the distance from a corresponding point on the aspheric surface to a plane tangent to the surface vertex, r is the distance from the corresponding point on the aspheric surface to the optical axis, c is the curvature of the aspheric surface vertex, k is a conical coefficient, and Ai is a coefficient corresponding to the ith high-order term in the aspheric surface type formula.

TABLE 2

Second embodiment

Referring to fig. 3 and 4, fig. 3 is a schematic diagram of the optical system 100 in the second embodiment, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with negative refractive power, a sixth lens element L6 with positive refractive power, and a seventh lens element L7 with negative refractive power. Fig. 4 is a graph of spherical aberration, astigmatism and distortion of the optical system 100 in the second embodiment, from left to right.

the object-side surface S13 of the seventh lens element L7 is concave at the paraxial region, and the image-side surface S14 is convex at the paraxial region.

In addition, the parameters of the optical system 100 are given in table 3, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

TABLE 3

Further, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are shown in table 4, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

TABLE 4

And, according to the above provided parameter information, the following data can be derived:

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

third embodiment

Referring to fig. 5 and 6, fig. 5 is a schematic diagram of the optical system 100 in the third embodiment, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, a sixth lens element L6 with negative refractive power, and a seventh lens element L7 with negative refractive power. Fig. 6 is a graph of spherical aberration, astigmatism and distortion of the optical system 100 in the third embodiment, from left to right.

The object-side surface S1 of the first lens element L1 is convex paraxially, and the image-side surface S2 is concave paraxially;

the object-side surface S9 of the fifth lens element L5 is convex and the image-side surface S10 is concave;

In addition, the parameters of the optical system 100 are given in table 5, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein again.

TABLE 5

Further, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are shown in table 6, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

TABLE 6

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

fourth embodiment

Referring to fig. 7 and 8, fig. 7 is a schematic diagram of the optical system 100 in the fourth embodiment, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, a sixth lens element L6 with negative refractive power, and a seventh lens element L7 with positive refractive power. Fig. 8 is a graph showing the spherical aberration, astigmatism and distortion of the optical system 100 in the fourth embodiment in order from left to right.

the object-side surface S9 of the fifth lens element L5 is convex paraxially, and the image-side surface S10 is convex paraxially;

the object-side surface S11 of the sixth lens element L6 is convex and the image-side surface S12 is concave;

In addition, the parameters of the optical system 100 are given in table 7, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

TABLE 7

Further, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are shown in table 8, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

TABLE 8

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

fifth embodiment

Referring to fig. 9 and 10, fig. 9 is a schematic diagram of the optical system 100 in the fifth embodiment, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with negative refractive power, a sixth lens element L6 with positive refractive power, and a seventh lens element L7 with negative refractive power. Fig. 10 is a graph showing the spherical aberration, astigmatism and distortion of the optical system 100 in the fifth embodiment in order from left to right.

the object-side surface S5 of the third lens element L3 is concave at the paraxial region thereof, and the image-side surface S6 is convex at the paraxial region thereof;

the object-side surface S7 of the fourth lens element L4 is convex and the image-side surface S8 is concave;

the object-side surface S11 of the sixth lens element L6 is convex paraxially, and the image-side surface S12 is convex paraxially;

In addition, the parameters of the optical system 100 are given in table 9, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

TABLE 9

Further, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are shown in table 10, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

Watch 10

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

referring to fig. 11, in some embodiments, the optical system 100 may be assembled with the photosensitive element 210 to form the image capturing module 200. At this time, the light-sensing surface of the light-sensing element 210 may be regarded as the image surface S17 of the optical system 100. The image capturing module 200 may further include an infrared filter L8, and the infrared filter L8 is disposed between the image side surface S14 and the image surface S17 of the seventh lens element L7. Specifically, the photosensitive element 210 may be a Charge Coupled Device (CCD) or a Complementary Metal-Oxide Semiconductor (CMOS) Device. By adopting the optical system 100 in the image capturing module 200, the magnifying power of the image capturing module 200 can be enhanced, so that the optical system 100 can adapt to the photosensitive elements with larger size and higher pixels, and the imaging quality of the optical system 100 is further improved. In addition, when the image capturing module 200 is used for imaging a long-distance object, the image capturing module can have excellent imaging quality, and the imaging quality of the image capturing module 200 in a dark environment can be improved.

Referring to fig. 11 and 12, in some embodiments, the image capturing module 200 may be applied to an electronic device 300, the electronic device includes a housing 310, and the image capturing module 200 is disposed in the housing 310. Specifically, the electronic apparatus 300 may be, but is not limited to, a wearable device such as a mobile phone, a video phone, a smart phone, an electronic book reader, a vehicle-mounted image capturing apparatus such as a car recorder, or a smart watch. The image capturing module 200 is adopted in the electronic device 300, and the imaging quality of the electronic device 300 can be improved by enhancing the magnifying power of the optical system 100. In addition, when the electronic device 300 images a long-distance subject, the electronic device 300 can have excellent imaging quality, and meanwhile, the imaging quality of the electronic device 300 in a dark environment can be improved.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. An optical system comprising, in order from an object side to an image side:

a third lens element with refractive power;

a fourth lens element with refractive power;

a fifth lens element with refractive power;

a sixth lens element with refractive power;

and the optical system satisfies the following conditional expression:

f*43/(ImgH*FNO)＜25；

2. The optical system according to claim 1, wherein the following conditional expression is satisfied:

1.9≤(|R32|+|R42|)/f≤7.2；

wherein R32 is a curvature radius of the image-side surface of the third lens element on the optical axis, and R42 is a curvature radius of the image-side surface of the fourth lens element on the optical axis.

3. The optical system according to claim 1, wherein the following conditional expression is satisfied:

5≤(|f2|+|f3|)/R31≤22；

wherein f2 is an effective focal length of the second lens, f3 is an effective focal length of the third lens, and R31 is a radius of curvature of an object-side surface of the third lens at an optical axis.

4. The optical system according to claim 1, wherein the following conditional expression is satisfied:

f/f1≤2；

wherein f1 is the effective focal length of the first lens.

5. The optical system as claimed in claim 1, wherein the fourth lens element has positive refractive power, at least one of the object-side surface and the image-side surface of the fifth lens element has an inflection point, and the optical system satisfies the following conditional expression:

|R41/R51|≤1；

wherein R41 is a radius of curvature of an object-side surface of the fourth lens element at an optical axis, and R51 is a radius of curvature of an object-side surface of the fifth lens element at the optical axis.

6. The optical system according to claim 1, wherein the following conditional expression is satisfied:

f≥7.2mm；

TTL≤7mm；

TTL/f≤1.0；

wherein, TTL is a distance on an optical axis from an object-side surface of the first lens element to an image plane of the optical system.

7. The optical system according to claim 1, wherein the following conditional expression is satisfied:

4≤(|f1|+|f2|+|f3|)/f≤27；

wherein f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, and f3 is the effective focal length of the third lens.

8. The optical system according to claim 1, wherein the following conditional expression is satisfied:

6≤TTL/(CT23+CT45)≤8.3；

wherein, TTL is an axial distance from an object-side surface of the first lens element to an image plane of the optical system, CT23 is an axial distance from an image-side surface of the second lens element to an object-side surface of the third lens element, and CT45 is an axial distance from an image-side surface of the fourth lens element to an object-side surface of the fifth lens element.

9. The optical system according to claim 1, wherein the following conditional expression is satisfied:

-0.5≤|R41|/f4≤0.2；

wherein R41 is a radius of curvature of an object-side surface of the fourth lens at an optical axis, and f4 is an effective focal length of the fourth lens.

10. An image capturing module, comprising a photosensitive element and the optical system of any one of claims 1 to 9, wherein the photosensitive element is disposed on an image side of the optical system.

11. An electronic device, comprising a housing and the image capturing module of claim 10, wherein the image capturing module is disposed on the housing.