CN113866942B

CN113866942B - Optical system, camera module and electronic equipment

Info

Publication number: CN113866942B
Application number: CN202111081364.3A
Authority: CN
Inventors: 邹金华; 李明
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2021-09-15
Filing date: 2021-09-15
Publication date: 2023-09-05
Anticipated expiration: 2041-09-15
Also published as: CN113866942A

Abstract

The invention relates to an optical system, an imaging module and electronic equipment. The optical system sequentially comprises from an object side to an image side along an optical axis: the first lens element with positive refractive power has a convex object-side surface and a convex image-side surface at a paraxial region; a second lens element with negative refractive power having a concave image-side surface at a paraxial region; a third lens element with refractive power; a fourth lens element with refractive power; a fifth lens element with refractive power having a concave image-side surface at a paraxial region; and satisfies the following conditional expression: 0.75mm < et3+et5+et7+et9<2.00mm, wherein ET3 is a distance in the optical axis direction between an edge of the first lens and an edge of the second lens, ET5 is a distance in the optical axis direction between an edge of the second lens and an edge of the third lens, ET7 is a distance in the optical axis direction between an edge of the third lens and an edge of the fourth lens, and ET9 is a distance in the optical axis direction between an edge of the fourth lens and an edge of the fifth lens. The optical system has the characteristics of small size, compact overall volume and miniaturization.

Description

Optical system, camera module and electronic equipment

Technical Field

The present invention relates to the field of photography imaging technology, and in particular, to an optical system, a camera module, and an electronic device.

Background

In recent years, with the continuous development of smart phones, the miniaturization of mobile phone lenses and the requirement of high-quality imaging quality are increasing, and with the advancement of semiconductor processing technology, the shrinking of pixel size of photosensitive elements, the thin, light, thin, short, and small-sized electronic products with excellent functions are necessarily a development trend. Camera modules are increasingly used, and the camera modules are assembled in various intelligent electronic products, vehicle-mounted devices, identification systems and entertainment sports equipment, so that the camera modules also become a great trend of future technological development. As today, mobile phones are equipped with one, two, or even more than three lenses with different photographing functions, which have become the main stream of the mobile phone market, and the volume of the photographing module directly depends on the number of lenses and the volume of each lens, so as to meet the development requirement of miniaturization of the photographing module, and how to reduce the size of the lens selected by the photographing module becomes an important problem to be solved.

However, in order to avoid the problem of excessive sensitivity of the lens due to interference between lenses during assembly, the conventional lens is generally designed to have a sufficiently large size, so that the volume of the lens is not easily reduced, and the purpose of miniaturization is difficult to achieve.

Disclosure of Invention

Accordingly, it is necessary to provide an optical system, an imaging module, and an electronic apparatus, which solve the problems of how to improve the size of the lens, and the difficulty in downsizing.

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

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

a second lens element with negative refractive power having a concave image-side surface at a paraxial region;

a third lens element with refractive power;

a fourth lens element with refractive power;

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

and the optical system satisfies the following conditional expression:

0.75mm<ET3+ET5+ET7+ET9<2.00mm；

wherein ET3 is the distance between the maximum effective aperture of the first lens image side surface and the maximum effective aperture of the second lens object side surface in the optical axis direction, ET5 is the distance between the maximum effective aperture of the second lens image side surface and the maximum effective aperture of the third lens object side surface in the optical axis direction, ET7 is the distance between the maximum effective aperture of the third lens image side surface and the maximum effective aperture of the fourth lens object side surface in the optical axis direction, and ET9 is the distance between the maximum effective aperture of the fourth lens image side surface and the maximum effective aperture of the fifth lens object side surface in the optical axis direction.

When the above conditional expression is satisfied, the interval between each adjacent lens is sufficiently compressed while ensuring the assembly manufacturability of the optical system, which is advantageous to reduce the optical total length of the optical system, thereby compressing the size and volume of the optical system, so that the optical system has the characteristics of miniaturization. If ET3+ ET5+ ET7+ ET9 is less than or equal to 0.75mm, the interval between every two adjacent lenses is too small, the space allowance distributed by a single lens is too small, so that the two adjacent lenses are too close, interference between the two adjacent lenses is easily caused when the optical system is assembled, the assembly sensitivity of the optical system is increased, and the assembly difficulty of the optical system is greatly increased; if ET3+ ET5+ ET7+ ET9 is not less than 2.00mm, then the interval between each adjacent lens is too big, and the space allowance that single lens distributes is too big, is unfavorable for compressing optical system's size, can't satisfy optical system's miniaturized demand of developing.

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

0.80<TT/BFL<1.50；

wherein TT is the distance between the object side surface of the first lens element and the image side surface of the fifth lens element on the optical axis, and BFL is the distance between the image side surface of the fifth lens element and the imaging surface of the optical system on the optical axis.

When the above conditional expressions are satisfied, the distance between the object side surface of the first lens element and the image side surface of the fifth lens element on the optical axis is kept within a reasonable range, and the distance between the image side surface of the fifth lens element and the image plane of the optical system is reasonably configured, so that the optical system can provide enough space to arrange the first lens element to the fifth lens element, and favorable conditions are provided for reasonably distributing the refractive power of each lens element and configuring the shape of each lens element of the optical system, thereby being favorable for compressing the size of the optical system, satisfying the miniaturization development requirement of the optical system, and simultaneously reasonably configuring the distance between the fifth lens element and the image plane, being favorable for the optical system to pick up a distant object, and further being capable of improving the telephoto imaging capability of the optical system. If TT/BFL is more than or equal to 1.50, the structure of the optical system is not compact enough, so that the total optical length of the optical system is too long, and the distance from the fifth lens to the imaging surface is too short, which is not beneficial to miniaturization of the optical system and assembly of the whole optical system. If TT/BFL is less than or equal to 0.80, the total optical length of the optical system is too small, and the aberration generated by each lens is difficult to effectively correct, so that the telephoto imaging quality of the optical system is poor.

0.60<f12/f<1.40；

wherein f12 is a combined focal length of the first lens and the second lens, and f is an effective focal length of the first lens.

When the above conditional expression is satisfied, the lens group formed by the first lens and the second lens can provide a reasonable positive refractive power for the optical system, can enhance the converging capability of the first lens and the second lens on light rays, and can prevent the first lens and the second lens from generating aberration which is difficult to correct, so that good imaging quality on an on-axis view field is obtained. When f12/f is greater than or equal to 1.40, the difference between the combined focal length of the lens group formed by the first lens and the second lens and the focal length of the optical system is larger and larger, and in contrast, the combined focal length of the lens group formed by the first lens and the second lens is larger and larger, and the refractive power provided by the lens group formed by the first lens and the second lens is smaller and smaller, so that the phenomenon that the refractive power provided by the lens group formed by the first lens and the second lens is insufficient for the optical system is easy to occur, and the light incident at a large angle relative to the optical axis is difficult to obtain reasonable deflection, thereby being unfavorable for expanding the field angle of the optical system. When f12/f is less than or equal to 0.60, the difference between the combined focal length of the lens group formed by the first lens and the second lens and the focal length of the optical system is smaller and smaller, and in contrast, the combined focal length of the lens group formed by the first lens and the second lens is smaller and smaller, and the refractive power provided by the lens group formed by the first lens and the second lens is directly increased and larger, so that the phenomenon that the refractive power provided by the lens group formed by the first lens and the second lens is too strong easily occurs, and the refractive angle of incident light is too large when the incident light passes through the first lens and the second lens, so that stronger astigmatism and chromatic aberration are easily generated, and high resolution imaging is not favored.

In one embodiment, the optical system further satisfies the conditional expression 0.60< f12/f < 1.40:

9.00mm＜f12＜12.00mm；

when the above conditional expression is satisfied, the lens group formed by the first lens and the second lens can better ensure that the lens group provides reasonable positive refractive power for the optical system, thereby being beneficial to enhancing the converging capability of the first lens and the second lens on light rays, further correcting the aberration generated by the first lens and the second lens, further obtaining high-quality imaging quality, being beneficial to compressing the total length of the optical system and further enhancing the telephoto imaging function of the optical system.

-45.00mm<f4*R10/f5<-2.00mm；

wherein f4 is an effective focal length of the fourth lens element, f5 is an effective focal length of the fifth lens element, and R10 is a radius of curvature of an image-side surface of the fifth lens element at the optical axis.

When the above conditional expression is satisfied, the refractive power of the fourth lens element and the refractive power of the fifth lens element are reasonably distributed, so that the system spherical aberration of the optical system can be effectively balanced, the aberration defect of the optical system is reduced, and meanwhile, the curvature radius of the image side surface of the fifth lens element is controlled, so that the image side surface of the fifth lens element is concave at the paraxial region and is bent to the image plane side of the optical system, which is favorable for converging the light of the central view field (i.e., the light at the center of the view field) on the image plane, and is favorable for effectively guiding the light of the edge view field (i.e., the light at the edge of the view field) to the image plane, effectively reducing the deflection angle of the light of the edge view field entering the photosensitive element, improving the relative brightness of the image pickup picture received by the photosensitive element, and making the image pickup picture on the image plane uniform and clear, thereby improving the image quality.

0.80<(CT1+CT2)/(CT3+CT4+CT5)<1.60；

wherein, CT1 is the thickness of the first lens on the optical axis, CT2 is the thickness of the second lens on the optical axis, CT3 is the thickness of the third lens on the optical axis, CT4 is the thickness of the fourth lens on the optical axis, and CT5 is the thickness of the fifth lens on the optical axis.

When the above conditional expressions are satisfied, the thickness of each lens is reasonably configured, which is beneficial to making the structure of the optical system more compact and meeting the demand of miniaturized design of the optical system, meanwhile, each lens is ensured to have proper thickness, the intensity deficiency caused by the over-thinness of each lens is avoided, the over-thinness of the lens has poor environmental endurance and high temperature or low Wen Yifa deformation, and simultaneously, the over-thinness of the lens is easy to crack during the lens assembly, thereby not only affecting the imaging of the optical system, but also reducing the manufacturing yield of the optical system and increasing the assembly difficulty of the optical system, and further increasing the manufacturing cost.

In one embodiment, when the above conditional expression of 0.80< (ct1+ct2)/(ct3+ct4+ct5) <1.60 is satisfied, the optical system further satisfies the conditional expression:

1.40mm<CT1<2.10mm；

when the above conditional expression is satisfied, the thickness of the first lens is ensured, the first lens is used as the lens closest to the object side, is sensitive to the change of the external environment, has enough thickness by controlling the first lens, effectively improves the structural strength of the first lens, strengthens the resistance of the first lens to the external environment, namely better avoids the phenomenon of cracking of the first lens caused by the impact of the external environment, plays a better protection effect on the whole optical system, and improves the use reliability of the optical system.

-1.50<(f1*R1)/(f2*R4)<-0.10；

wherein f1 is an effective focal length of the first lens element, R1 is a radius of curvature of an object-side surface of the first lens element at the optical axis, f2 is an effective focal length of the second lens element, and R4 is a radius of curvature of an image-side surface of the second lens element at the optical axis.

When the above conditional expression is satisfied, the curvature radius of the object side surface of the first lens element and the curvature radius of the object side surface of the second lens element are reasonably controlled, so that the first lens element and the second lens element have reasonable surface shapes, and the refractive power of the first lens element and the refractive power of the second lens element are reasonably matched, so that the incident light rays can be reasonably converged to compress the total length of the optical system, the first lens element and the second lens element have opposite refractive powers, the positive and negative lens element can mutually offset the aberration generated by the positive and negative lens element, the positive spherical aberration and the negative spherical aberration generated by the optical system can mutually offset, the aberration which is difficult to correct by the first lens element and the second lens element can be prevented, and the imaging quality is improved.

0.85<SD52/CT5<3.75；

wherein SD52 is half of the maximum effective aperture of the image-side surface of the fifth lens element, and CT5 is the thickness of the fifth lens element on the optical axis.

When the above conditional expression is satisfied, the radial dimension of the fifth lens is reasonably controlled, which is favorable for controlling the outer diameter dimension of the optical system, avoiding the optical system from having a large aperture, reasonably controlling the thickness of the fifth lens, and being favorable for reducing the thickness of the fifth lens on the optical axis, thereby promoting the miniaturization development of the optical system.

1.60< nd3<1.70, and 1.60< nd4<1.70;

wherein Nd3 is the refractive index of the third lens, and Nd4 is the refractive index of the fourth lens.

When the above conditional expression is satisfied, the deflection degree of the light passing through the third lens and the fourth lens can be controlled, which is favorable for strengthening the correction capability of the third lens and the fourth lens to the aberration, effectively correcting the aberration generated by the first lens and the second lens, reducing the correction pressure of the fifth lens and being favorable for balancing the aberration generated by the optical system.

0.50<|R9/R10|<15.00；

wherein R9 is a radius of curvature of the object side surface of the fifth lens element at the optical axis, and R10 is a radius of curvature of the image side surface of the fifth lens element at the optical axis.

When the above conditional expression is satisfied, the ratio between the radius of curvature of the object side surface of the fifth lens element at the optical axis and the radius of curvature of the image side surface of the fifth lens element at the optical axis is controlled within a reasonable range, so that the problem that the fifth lens element is difficult to mold due to excessive bending of the surface shape of the fifth lens element is avoided, and the lens molding yield of the fifth lens element is improved; and the reasonable surface design of the fifth lens is beneficial to enabling the light passing through the object lens to be better converged on the imaging surface, thereby improving the imaging quality.

1.50<ET4/(|SAG41|+|SAG42|)<22.00；

wherein ET4 is the distance between the maximum effective aperture of the object side of the fourth lens element and the maximum effective aperture of the image side of the fourth lens element in the optical axis direction (i.e., the edge thickness of the fourth lens element in the optical axis direction), SAG41 is the sagittal height of the object side of the fourth lens element at the maximum effective aperture, and SAG42 is the sagittal height of the image side of the fourth lens element at the maximum effective aperture.

When the above conditional expression is satisfied, the ratio between the edge thickness of the fourth lens and the sum of the absolute values of the sagittal heights of the object side surface and the image side surface of the fourth lens is reasonably controlled, so that the thickness of the fourth lens is suitable, the thickness of the fourth lens is used as an intermediate lens, the design space in the optical system is reasonable, the optical total length of the optical system is reduced, the processability of the fourth lens is improved, and the design and assembly sensitivity is reduced. If ET 4/(|sag 41|+|sag 42|) is less than or equal to 1.50, the edge thickness of the fourth lens is too small, the rise of the object side and the image side of the fourth lens is too large, so that the drop of the center thickness and the edge thickness of the fourth lens is too large, severe surface type change easily occurs in the forming process of the fourth lens, the processing and forming difficulty of the fourth lens is large, abrasion easily occurs in the assembling process of the fourth lens, the manufacturing cost of an optical system is increased, interference easily occurs between the fourth lens and an adjacent lens, and the sensitivity of the optical system is increased; if ET 4/(|SAG 41|+|SAG 42|) is not less than 22.00, the edge thickness of the fourth lens is too large, so that the material input cost is increased, the whole weight of the optical system is easy to increase, and the light and thin design of the optical system is not facilitated.

The image pickup module comprises a reflecting prism, a photosensitive element and the optical system, wherein the reflecting prism is arranged on the object side of the optical system, and the photosensitive element is arranged on the image side of the optical system. In the structure, the miniaturized optical system is favorable for compressing the volume of the camera module, is favorable for the miniaturized design of the camera module, simultaneously forms the periscope lens through the cooperation arrangement of the reflecting prism and the optical system, and the reflecting prism turns the transmission path of incident light rays, so that the turned light rays are incident into the optical system along the optical total length extending direction (namely the arrangement direction of each lens) of the optical system, thereby realizing the periscope function of the periscope lens, and the long focal length of the periscope lens is favorable for realizing the tele function, wherein the incident direction of the incident light rays is perpendicular to the optical total length extending direction of the optical system, thereby avoiding the overlarge influence of the optical total length of the optical system on the thickness design of the camera module in the incident direction of the incident light rays, being favorable for shortening the thickness of the camera module in the incident direction of the incident light rays, reducing the size of the camera module, and ensuring that the camera module has miniaturized characteristics and simultaneously has the periscope function.

An electronic device comprises a fixing piece and the camera shooting module, wherein the camera shooting module is arranged on the fixing piece. By adopting the camera module, the size and the volume of the electronic equipment are reduced, the electronic equipment has the characteristic of miniaturization, and meanwhile, the periscope camera function of the electronic equipment is realized through the periscope lens of the camera module.

Drawings

Fig. 1 is a schematic structural diagram of an optical system according to a first embodiment of the present application;

FIG. 2 includes a longitudinal spherical aberration, astigmatism and distortion curves of the optical system in the first embodiment;

FIG. 3 is a schematic diagram of an optical system according to a second embodiment of the present application;

FIG. 4 includes longitudinal spherical aberration, astigmatism and distortion plots of the optical system in a second embodiment;

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

FIG. 6 includes longitudinal spherical aberration, astigmatism and distortion plots of the optical system in a third embodiment;

fig. 7 is a schematic structural diagram of an optical system according to a fourth embodiment of the present application;

FIG. 8 includes a longitudinal spherical aberration, astigmatism and distortion plots of the optical system in a fourth embodiment;

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

FIG. 10 includes a longitudinal spherical aberration, astigmatism and distortion curves of the optical system in a fifth embodiment;

fig. 11 is a schematic structural view of an optical system according to a sixth embodiment of the present application;

FIG. 12 includes a longitudinal spherical aberration, astigmatism and distortion curves of the optical system in the sixth embodiment;

FIG. 13 is a schematic diagram of an image capturing module according to an embodiment of the present application;

fig. 14 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

Detailed Description

In order that the above objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the application, whereby the application is not limited to the specific embodiments disclosed below.

In the description of the present application, it should 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", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

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 at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. 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 the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that when an element is referred to as being "fixed" 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 are used herein for illustrative purposes only and are not meant to be the only embodiment.

Referring to fig. 1, an embodiment of the present application provides an optical system 10 having a five-piece structure, where the optical system 10 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5 in order from an object side to an image side along an optical axis 101. The lenses in the optical system 10 are coaxially arranged, i.e. the optical axes of the lenses are all on the same line, which may be referred to as the optical axis 101 of the optical system 10. The above-described optical elements in the optical system 10 and the aperture stop not mentioned at the outset may be assembled with a lens barrel to constitute an imaging lens.

The first lens element L1 has positive refractive power, the second lens element L2 has negative refractive power, and any one of the third lens element L3, the fourth lens element L4 and the fifth lens element L5 can have positive refractive power or negative refractive power, so that the optical system 10 has a plurality of different combinations of refractive powers, and the refractive powers of the third lens element L3, the fourth lens element L4 and the fifth lens element L5 can be specifically selected according to the actual design requirements.

The first lens element L1 comprises an object-side surface S1 and an image-side surface S2, the second lens element L2 comprises an object-side surface S3 and an image-side surface S4, the third lens element L3 comprises an object-side surface S5 and an image-side surface S6, the fourth lens element L4 comprises an object-side surface S7 and an image-side surface S8, and the fifth lens element L5 comprises an object-side surface S9 and an image-side surface S10. In addition, the optical system 10 further has an imaging plane Si, which is located at the image side of the fifth lens L5. In general, the imaging surface Si of the optical system 10 coincides with the photosensitive surface of the photosensitive element, and for ease of understanding, the imaging surface Si may be regarded as the photosensitive surface of the photosensitive element.

In the embodiment of the application, the image-side surface S2 of the first lens element L1 is convex at the paraxial region 101, the image-side surface S4 of the second lens element L2 is concave at the paraxial region 101, and the image-side surface of the fifth lens element L5 is concave at the paraxial region, and the object-side or image-side surface of each lens element, which is not mentioned herein, may be specifically configured according to practical design requirements. The refractive power combination and the surface type combination of the lenses of the optical system 10 are beneficial to the long coking design of the optical system 10, and the refractive power property and the surface type matching of the lenses arranged from the object side to the image side in the system are reasonable, so that the correction of aberration is also beneficial.

It should be noted that while embodiments of the present application describe a lens with one side being convex at a paraxial region, it is to be understood that the lens has the side being convex in a region near the optical axis; when describing a lens with one side that is concave at the circumference, it is understood that the side is concave in the area near the maximum effective aperture. For example, when the side surface is convex at a paraxial region and is also convex at a circumferential region, the shape of the side surface from the center (optical axis) to the edge direction may be purely convex; or first transition from a convex shape in the center to a concave shape and then become convex near the maximum effective aperture. When it is described that the lens surface is convex at least at the paraxial region, the lens surface may be convex or concave at the periphery. On the other hand, when it is described that the lens surface is convex, the lens surface as a whole appears convex, i.e. convex at both the paraxial and the near-circumferential positions, but the curvature of the surface may be the same or different throughout. For economy of description, the above is given by way of example only with respect to a particular surface type.

On the other hand, in the embodiment of the present application, the optical system 10 satisfies the conditional expression:

0.75mm < ET3+ET5+ET7+ET9<2.00mm; wherein:

ET3 is the distance between the maximum effective aperture of the image side surface S2 of the first lens element L1 and the maximum effective aperture of the object side surface S3 of the second lens element L2 in the direction of the optical axis 101, i.e., the distance between the edge of the first lens element L1 and the edge of the second lens element L2 in the direction of the optical axis 101;

ET5 is the distance between the maximum effective aperture of the image-side surface S4 of the second lens element L2 and the maximum effective aperture of the object-side surface S5 of the third lens element L3 in the direction of the optical axis 101, i.e., the distance between the edge of the second lens element L2 and the edge of the third lens element L3 in the direction of the optical axis 101 is set as ET 5;

ET7 is the distance between the maximum effective aperture of the image-side surface S6 of the third lens element L3 and the maximum effective aperture of the object-side surface S7 of the fourth lens element L4 in the direction of the optical axis 101, i.e., the distance between the edge of the third lens element L3 and the edge of the fourth lens element L4 in the direction of the optical axis 101 is set as ET 7;

ET9 is the distance between the maximum effective aperture of the image-side surface S8 of the fourth lens element L4 and the maximum effective aperture of the object-side surface S9 of the fifth lens element L5 in the direction of the optical axis 101, i.e., the distance between the edge of the fourth lens element L4 and the edge of the fifth lens element L5 in the direction of the optical axis.

When the above conditional expression is satisfied, the separation distance between the lenses is sufficiently compressed while ensuring the assembly manufacturability of the optical system 10, which is advantageous to reduce the size of the optical system 10, thereby compressing the volume of the optical system 10, so that the optical system 10 has the characteristic of miniaturization. If ET3+ ET5+ ET7+ ET9 is less than or equal to 0.75mm, the space allowance allocated between each lens is too small, so that two adjacent lenses are too close, interference between the two adjacent lenses is easily caused when the optical system 10 is assembled, the sensitivity of the optical system 10 is increased, and the assembly difficulty of the optical system 10 is greatly increased; if ET3+ ET5+ ET7+ ET9 is greater than or equal to 2.00mm, then the space allowance is too big to be favorable to compressing the size of optical system 10, can't satisfy the demand of optical system 10 miniaturization development. In some embodiments, the numerical values of the above conditional expression may be specifically 0.900mm, 1.069mm, 1.347mm, 1.434mm, 1.550mm, 1.690mm, or 1.771mm.

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

0.80<TT/BFL<1.50；

where TT is the distance on the optical axis 101 between the object side surface S1 of the first lens element L1 and the image side surface S10 of the fifth lens element L5, and BFL is the distance on the optical axis 101 between the image side surface S10 of the fifth lens element L5 and the imaging surface Si of the optical system 10.

When the above conditional expressions are satisfied, the distance between the object side surface S1 of the first lens L1 and the image side surface S10 of the fifth lens L5 on the optical axis 101 is kept within a reasonable range, and the distance between the image side surface S10 of the fifth lens L5 and the image side surface Si of the optical system 10 on the optical axis 101 is reasonably configured, that is, the optical system 10 can provide enough space to arrange the first lens L1 to the fifth lens L5, which provides advantages for reasonably distributing the focal length of each lens and configuring the shape of each lens of the optical system 10, which is beneficial for compressing the size of the optical system 10, satisfying the requirement for miniaturization development of the optical system 10, and meanwhile, also reasonably configuring the distance between the lenses and the image plane Si, which is beneficial for the optical system 10 to pick up long-distance objects, thereby improving the telephoto imaging capability of the optical system 10. If TT/BFL is greater than or equal to 1.50, the structure of the optical system 10 is not compact enough, resulting in an excessively long total optical length of the optical system 10, while the distance from the fifth lens L5 to the imaging plane Si is too short, which is not beneficial to miniaturization of the optical system 10 and assembly of the optical system 10. If TT/BFL is less than or equal to 0.80, the total optical length of the optical system 10 is too small to correct aberrations generated by the lens, resulting in poor telephoto imaging quality of the optical system 10. In some embodiments, the numerical value of the above conditional expression may be specifically 0.981, 1.032, 1.232, 1.240, 1.254, 1.291, or 1.322.

0.60<f12/f<1.40；

Wherein f12 is a combined focal length of the first lens L1 and the second lens L2, and f is an effective focal length of the first lens L1.

When the above conditional expression is satisfied, the lens group formed by the first lens element L1 and the second lens element L2 can provide a reasonable positive refractive power for the optical system 10, can enhance the converging capability of the first lens element L1 and the second lens element L2 to light, and can prevent the first lens element L1 and the second lens element L2 from generating aberrations which are difficult to correct, so as to obtain good imaging quality on the on-axis field of view. When f12/f is greater than or equal to 1.40, the difference between the focal length of the lens group formed by the first lens element L1 and the second lens element L2 and the focal length of the optical system 10 is larger and larger, and in contrast, the focal length of the lens group formed by the first lens element L1 and the second lens element L2 is larger and larger, and the refractive power of the lens group formed by the first lens element L1 and the second lens element L2 is smaller and smaller, such that the phenomenon that the refractive power of the lens group formed by the first lens element L1 and the second lens element L2 is insufficient for the optical system 10 is easy to occur, so that light incident at a large angle with respect to the optical axis is difficult to be reasonably deflected, which is unfavorable for expanding the angle of view of the optical system 10. When f12/f is less than or equal to 0.60, the difference between the focal length of the lens group formed by the first lens element L1 and the second lens element L2 and the focal length of the optical system 10 is smaller, and in contrast, the focal length of the lens group formed by the first lens element L1 and the second lens element L2 is smaller, and the refractive power provided by the lens group formed by the first lens element L1 and the second lens element L2 is larger, so that the phenomenon of excessively strong refractive power provided by the lens group formed by the first lens element L1 and the second lens element L2 easily occurs, and the refractive angle of the incident light is excessively large when passing through the first lens element L1 and the second lens element L2, so that stronger astigmatism and chromatic aberration are easily generated, which is unfavorable for high resolution imaging. In some embodiments, the numerical values of the above conditional expressions may be specifically 0.823, 0.864, 0.892, 0.993, 0.998, 1.015, or 1.016.

In one embodiment, the optical system 10 further satisfies the conditional expression 0.60< f12/f <1.40 on the condition that the conditional expression is satisfied:

9.00mm＜f12＜12.00mm；

when the above conditional expression is satisfied, the lens group formed by the first lens element L1 and the second lens element L2 is better able to provide a reasonable positive refractive power for the optical system 10, which is beneficial to enhancing the converging capability of the first lens element L1 and the second lens element L2 to light rays, further correcting the aberration generated by the first lens element L1 and the second lens element L2, thereby obtaining high-quality imaging quality, and further, being beneficial to compressing the total length of the optical system 10 and further enhancing the telephoto imaging function of the optical system 10. In some embodiments, the numerical value of the above conditional expression may be specifically 9.71mm, 9.90mm, 10.01mm, 11.78mm, 11.80mm, 13.24mm, or 14.09mm.

-45.00mm<f4*R10/f5<-2.00mm；

Wherein f4 is an effective focal length of the fourth lens element L4, f5 is an effective focal length of the fifth lens element L5, and R10 is a radius of curvature of the image-side surface S10 of the fifth lens element L5 at the paraxial region 101.

When the above conditional expression is satisfied, by reasonably distributing the refractive power of the fourth lens element L4 and the refractive power of the fifth lens element L5, the system spherical aberration of the optical system 10 can be effectively balanced, the aberration defect of the optical system 10 can be reduced, and the radius of curvature of the image-side surface S10 of the fifth lens element L5 can be controlled, so that the image-side surface S10 of the fifth lens element L5 is concave at the paraxial region 101, and is bent towards the imaging surface Si of the optical system 10, which is beneficial to converging the central field-of-view light (i.e., the light at the center of the field-of-view) on the imaging surface Si, and guiding the marginal field-of-view light (i.e., the light at the edge of the field-of-view) to the imaging surface Si, which effectively reduces the deflection angle of the marginal field-of-view light entering the photosensitive element, and improves the relative brightness of the image received by the photosensitive element, so that the image on the imaging surface Si is uniform and clear. In some embodiments, the numerical values of the above conditional expressions may be specifically-40.913, -20.480, -7.904, -6.681, -4.736, -4.218, or-3.927.

0.80<(CT1+CT2)/(CT3+CT4+CT5)<1.60；

Wherein, CT1 is the thickness of the first lens L1 on the optical axis 101, CT2 is the thickness of the second lens L2 on the optical axis 101, CT3 is the thickness of the third lens L3 on the optical axis 101, CT4 is the thickness of the fourth lens L4 on the optical axis 101, and CT5 is the thickness of the fifth lens L5 on the optical axis 101.

When the above conditional expressions are satisfied, the thickness of each lens is properly configured, which is favorable for making the structure of the optical system 10 more compact, and meeting the demand of miniaturized design of the optical system 10, and simultaneously, each lens is ensured to have proper thickness, so that the insufficient strength caused by the over-thinness of each lens is avoided, the over-thinness of the lens has poor environmental endurance, high temperature or low Wen Yifa deformation, and simultaneously, the over-thinness of the lens is easy to crack during lens assembly, thereby not only affecting the imaging of the optical system 10, but also reducing the manufacturing yield of the optical system 10, increasing the assembly difficulty of the optical system 10, and further increasing the manufacturing cost. In some embodiments, the numerical value of the above conditional expression may be specifically 0.855, 0.922, 0.997, 1.012, 1.112, 1.494, or 1.538.

In one embodiment, when the above conditional expression of 0.80< (ct1+ct2)/(ct3+ct4+ct5) <1.60 is satisfied, the optical system 10 further satisfies the conditional expression:

1.40mm<CT1<2.10mm；

When the above conditional expression is satisfied, the thickness of the first lens L1 is ensured, the first lens L1 is used as the lens closest to the object side, and is sensitive to the change of the external environment, and the structural strength of the first lens L1 is effectively improved by controlling the first lens L1 to have enough thickness, so that the resistance of the first lens L1 to the external environment is enhanced, namely, the phenomenon of cracking of the first lens L1 caused by the impact of the external environment is better avoided, the whole optical system 10 has better protection effect, and the use reliability of the optical system 10 is improved. In some embodiments, the numerical values of the above conditional expression may be specifically 1.411mm, 1.471mm, 1.492mm, 1.506mm, 1.654mm, 2.021mm, or 2.037mm.

-1.50<(f1*R1)/(f2*R4)<-0.10；

Wherein f1 is an effective focal length of the first lens element L1, R1 is a radius of curvature of the object-side surface S1 of the first lens element L1 at the paraxial region 101, f2 is an effective focal length of the second lens element L2, and R4 is a radius of curvature of the image-side surface S4 of the second lens element L2 at the paraxial region 101.

When the above conditional expression is satisfied, by reasonably controlling the radii of curvature of the object side surface S1 of the first lens element L1 and the object side surface S3 of the second lens element L2, the first lens element L1 and the second lens element L2 have reasonable surface shapes, and the refractive power of the first lens element L1 and the refractive power of the second lens element L2 are reasonably matched, so that the incident light can be reasonably converged to compress the total length of the optical system 10, and the first lens element L1 and the second lens element L2 have opposite refractive powers, so that the positive spherical aberration and the negative spherical aberration generated in the optical system 10 can be mutually offset, the aberration difficult to correct generated by the first lens element L1 and the second lens element L2 can be effectively prevented, and the imaging quality can be improved. In some embodiments, the numerical values of the above conditional expression may be specifically-1.045, -0.862, -0.671, -0.633, -0.451, -0.230, or-0.201.

0.85<SD52/CT5<3.75；

The SD52 is half of the maximum effective aperture of the image-side surface S10 of the fifth lens element L5, and the CT5 is the thickness of the fifth lens element L5 on the optical axis 101.

When the above conditional expression is satisfied, the radial dimension of the fifth lens L5 is reasonably controlled, which is favorable for controlling the outer diameter dimension of the optical system 10, avoiding the optical system 10 from having a large aperture, and reasonably controlling the thickness of the fifth lens L5, which is favorable for reducing the thickness of the fifth lens L5 on the optical axis 101, thereby promoting the miniaturization development of the optical system 10. In some embodiments, the numerical value of the above conditional expression may be specifically 0.929, 1.674, 2.063, 2.067, 2.870, 3.600, or 3.686.

1.60< nd3<1.70, and 1.60< nd4<1.70;

wherein Nd3 is the refractive index of the third lens L3, and Nd4 is the refractive index of the fourth lens L4.

When the above conditional expression is satisfied, the degree of deflection of the light passing through the third lens L3 and the fourth lens L4 can be controlled, which is favorable for enhancing the aberration correction capability of the third lens L3 and the fourth lens L4, i.e. effectively correcting the aberration generated by the first lens L1 and the second lens L2, and reducing the correction pressure of the fifth lens L5, which is favorable for balancing the chromatic aberration generated by the optical system 10. In some embodiments, the above Nd3 may have a value of 1.635, 1.639, or 1.671, and Nd4 may have a value of 1.614, 1.635, or 1.671, in particular.

0.50<|R9/R10|<15.00；

Wherein R9 is a radius of curvature of the object-side surface S9 of the fifth lens element L5 at the paraxial region 101, and R10 is a radius of curvature of the image-side surface S10 of the fifth lens element L5 at the paraxial region 101.

When the above condition is satisfied, the ratio between the radius of curvature of the object-side surface S9 of the fifth lens element L5 at the paraxial region 101 and the radius of curvature of the image-side surface S10 of the fifth lens element L5 at the paraxial region 101 is controlled within a reasonable range, so that the problem of difficult molding caused by excessively bending the shape of the fifth lens element L5 is avoided, and the lens molding yield of the fifth lens element L5 is improved; and the reasonable surface design of the fifth lens L5 is beneficial to enabling the light passing through the object lens to be better converged on the imaging surface Si, so that the imaging quality is improved. In some embodiments, the numerical value of the above conditional expression may be specifically 0.658, 1.595, 6.519, 8.361, 9.872, 11.752 or 14.564.

1.50<ET4/(|SAG41|+|SAG42|)<22.00；

Wherein ET4 is the distance between the maximum effective aperture of the object-side surface S7 of the fourth lens element L4 and the maximum effective aperture of the image-side surface S8 of the fourth lens element L4 in the optical axis 101 direction (i.e., the thickness of the edge of the fourth lens element L4 in the optical axis 101 direction), SAG41 is the sagittal height of the object-side surface S7 of the fourth lens element L4 at the maximum effective aperture, and SAG42 is the sagittal height of the image-side surface S8 of the fourth lens element L4 at the maximum effective aperture.

When the above conditional expression is satisfied, the ratio between the edge thickness of the fourth lens element L4 and the sum of the sagittal absolute values of the object-side surface S7 and the image-side surface of the fourth lens element L4 is reasonably controlled, so that the thickness of the fourth lens element L4 is suitable, and the design space in the optical system 10 is reasonable as a lens located in the middle of the optical system 10, which is beneficial to reducing the total optical length of the optical system 10, improving the workability of the fourth lens element L4, and reducing the design and assembly sensitivity. If ET 4/(|sag 41|+|sag 42|) is less than or equal to 1.50, the edge thickness of the fourth lens L4 is too small, and the sagittal height of the object side and the image side of the fourth lens L4 is too large, so that the drop of the center thickness and the edge thickness of the fourth lens L4 is too large, severe surface type changes easily occur in the forming process of the fourth lens L4, the forming difficulty of the fourth lens L4 is large, abrasion easily occurs in the assembling process of the fourth lens L4, the manufacturing cost of the optical system 10 is increased, interference with adjacent lenses easily occurs, and the sensitivity of the optical system 10 is increased; if ET 4/(|sag 41|+|sag 42|) is equal to or greater than 22.00, the edge thickness of the fourth lens L4 is too large, which not only increases the material input cost, but also easily increases the overall weight of the optical system 10, and is not beneficial to realizing the light and thin design of the optical system 10. In some embodiments, the numerical value of the above conditional expression may be specifically 1.616, 1.800, 2.430, 5.807, 6.205, 12.343, or 21.079.

The above conditional expressions and the technical effects thereof are directed to the five-sheet optical system 10 having the above lens design. If the lens design (lens number, refractive power configuration, surface configuration, etc.) of the optical system 10 cannot be ensured, it is difficult to ensure that the optical system 10 still has the corresponding technical effects while satisfying these relationships, and there is a possibility that the image capturing performance may be significantly degraded.

The optical system 10 includes a stop STO, which is an aperture stop, for controlling the amount of light entering the optical system 10 and, at the same time, can function to block non-effective light. When the projection of the stop STO on the optical axis 101 overlaps with the projection of the object side surface S1 of the first lens L1 on the optical axis 101, it may also be considered that the stop STO is disposed on the object side of the first lens L1, and at this time, at least a partial area of the object side surface S1 of the first lens L1 passes through the stop STO toward the object side. The stop STO may be disposed on the object side of the first lens L1, or may be disposed between two adjacent lenses of the first lens L1 to the fifth lens L5. The stop STO may be formed of a barrel structure that holds the lens, or may be a gasket that is fitted separately between the lens and the barrel.

In some embodiments, the object-side surface and/or the image-side surface of at least one of the first lens L1 to the fifth lens L5 is aspheric, i.e., at least one of the first lens L1 to the fifth lens L5 has an aspheric surface shape. For example, the object-side surfaces and the image-side surfaces of the first lens element L1 to the fifth lens element L5 may be aspheric. The aspheric surface type arrangement can further help the optical system 10 eliminate aberration, solve the problem of distortion of vision, and is beneficial to miniaturization design of the optical system 10, so that the optical system 10 can have excellent optical effect on the premise of keeping miniaturization design. Of course, in other embodiments, at least one of the first lens element L1 to the fifth lens element L5 can have a spherical object-side surface and/or an image-side surface. It should be noted that the actual shape of the lens is not limited to the spherical or aspherical shape shown in the drawings, which are for example only and are not drawn to scale. It should be noted that when the object side surface or the image side surface of a lens is an aspherical surface, the surface may be a structure that is entirely convex or entirely concave. Alternatively, the face may be designed to have a inflection point, where the face shape from center to edge will change, e.g., the face is convex at the center and concave at the edges. The specific surface-type structure (concave-convex relationship) of either side of any lens may be various, and is not limited to the above-described examples, which are only examples made herein for explaining the relationship between the paraxial region and the circumferential region. It should be noted that there may be some deviation in the ratio of the dimensions of the thickness of each lens, the radius of curvature of the surface, etc. in the drawings.

In some embodiments, at least one lens of the optical system 10 is made of Plastic (PC), 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 (GL). 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, at least two lenses of different materials may be disposed in the optical system 10, for example, a combination of glass lenses and plastic lenses may be used, but the specific configuration relationship may be determined according to practical needs, which is not meant to be exhaustive.

In some embodiments, the optical system 10 includes an infrared cut filter 110, where the infrared cut filter 110 is disposed on the image side of the fifth lens L5 and is disposed opposite to each lens in the optical system 10. The ir cut filter 110 is used to filter out ir light, and prevent ir light from reaching the imaging surface Si of the system, thereby preventing ir light from interfering with normal imaging. An infrared cut filter 110 may be assembled with each lens as part of the optical system 10. In other embodiments, the ir cut filter 110 is not a component of the optical system 10, and the ir cut filter 110 may be installed between the optical system 10 and the photosensitive element when the optical system 10 and the photosensitive element are assembled into the image capturing module. In some embodiments, the ir cut filter 110 may also be disposed on the object side of the first lens L1. In addition, in some embodiments, the filtering effect of the infrared light can also be achieved by providing a filtering coating on at least one of the first lens L1 to the fifth lens L5.

The optical system 10 of the present application is illustrated by the following more specific examples:

first embodiment

Referring to fig. 1 and 2, in the first embodiment, the optical system 10 includes, in order from an object side to an image side along an optical axis 101, a stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with negative refractive power, a fourth lens L4 with positive refractive power, and a fifth lens L5 with negative refractive power. The surface profile of each lens surface in the optical system 10 is as follows:

the object side surface S1 of the first lens element L1 is convex at a paraxial region, and the image side surface S2 is convex at a paraxial region; the object side surface S1 is convex at the circumference, and the image side surface S2 is convex at the circumference.

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

The third lens element L3 has a convex object-side surface S5 at a paraxial region and a concave image-side surface S6 at a paraxial region; the object side surface S5 is convex at the circumference and the image side surface S6 is concave at the circumference.

The fourth lens element L4 has a convex object-side surface S7 at a paraxial region and a concave image-side surface S8 at a paraxial region; the object side surface S7 is convex at the circumference and the image side surface S8 is concave at the circumference.

The fifth lens element L5 has a convex object-side surface S9 at a paraxial region and a concave image-side surface S10 at a paraxial region; the object side surface S9 is concave at the circumference and the image side surface S10 is convex at the circumference.

The object side surface and the image side surface of any one of the first lens L1 to the fifth lens L5 are aspheric, and the first lens L1 to the fifth lens L5 are plastic.

In the optical system 10 of the first embodiment, the combination of the refractive power, the surface shape combination and the material combination of the lens elements is beneficial to the long coking design of the optical system 10, and the refractive power and the surface shape matching of the lens elements arranged from the object side to the image side in the system are reasonable, so that the correction of aberration is also beneficial.

The various lens parameters of the optical system 10 in this embodiment are presented in table 1 below. The elements from the object side to the image side of the optical system 10 are arranged in order from top to bottom in table 1, where STO characterizes the aperture stop. The infrared filter 110 may be part of the optical system 10 or may be removable from the optical system 10, but the total optical length of the optical system 110 remains the same after the infrared filter 110 is removed. The infrared filter 110 is used for filtering infrared light.

The radius Y in table 1 is the radius of curvature of the corresponding surface of the lens at the optical axis 101 and in the Y direction. The absolute value of the first value of the lens in the "thickness" parameter row is the thickness of the lens on the optical axis 101, and the absolute value of the second value is the distance from the image side of the lens to the subsequent optical element (lens or diaphragm) on the optical axis 101, wherein the thickness parameter of the diaphragm represents the distance from the diaphragm surface to the object side of the adjacent lens on the optical axis 101. The refractive index, abbe number, and focal length (effective focal length) of each lens in the table are 587.6nm, and the Y radius, thickness, and focal length (effective focal length) are all in millimeters (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.

TABLE 1

As is clear from table 1, the optical system 10 in the first embodiment has an effective focal length f of 11.60mm, an f-number FNO of 3.46, a maximum half field angle (i.e., half of the maximum field angle) HFOV of 11.30 °, an optical total length TTL of 10.70mm, a small size of the optical system 10, a long focal length, a small size, a long focal length, and good image quality. When the image sensor is assembled, the FOV can also be understood as the maximum field angle of the optical system 10 in the diagonal direction of the rectangular effective pixel area of the corresponding image sensor.

Table 2 below presents the aspherical coefficients of the corresponding lens surfaces in table 1, where K is a conic coefficient and Ai is a coefficient corresponding to the i-th order higher order term in the aspherical surface type formula.

TABLE 2

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

where Z is the sagittal height of the corresponding position of the lens surface, r is the distance from the corresponding position of the lens surface to the optical axis, c is the curvature of the lens surface at the optical axis 101, k is the conic coefficient, ai is the coefficient corresponding to the i-th order higher order term. It should be noted that the actual planar shape of the lens is not limited to the shape shown in the drawings, which are not drawn to scale, and may differ from the actual planar structure of the lens to some extent.

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

et3+et5+et7+et9=1.77 mm, the space distance between the lenses is fully compressed while the assembly manufacturability of the optical system 10 is ensured, and the size of the optical system 10 is effectively reduced, so that the volume of the optical system 10 is reduced, and the optical system 10 has the characteristic of miniaturization.

TT/bfl=1.25, it is achieved that the distance between the object side surface S1 of the first lens L1 and the image side surface S10 of the fifth lens L5 on the optical axis 101 is reasonably controlled, and at the same time, the distance between the image side surface S10 of the fifth lens L5 and the imaging surface Si of the optical system 10 on the optical axis 101 is also reasonably configured, that is, the optical system 10 can provide enough space to arrange the first lens L1 to the fifth lens L5, which provides advantages for reasonably distributing the focal length of each lens and configuring the shape of each lens of the optical system 10, which is beneficial for compressing the size of the optical system 10, meeting the requirement of miniaturization development of the optical system 10, and at the same time, also reasonably configuring the distance between the lens and the imaging surface Si, which is beneficial for the optical system 10 to pick up long-distance objects, thereby improving the telephoto imaging capability of the optical system 10.

f12/f=1.01, where the lens group formed by the first lens element L1 and the second lens element L2 can provide a reasonable positive refractive power for the optical system 10, so that the converging capability of the first lens element L1 and the second lens element L2 to light is enhanced, and when the first lens element L1 and the second lens element L2 are prevented from generating aberrations that are difficult to correct, good imaging quality on the on-axis field of view is obtained, and in addition, the lens group provides a reasonable positive refractive power for the optical system 10, so that a reasonable convergence to compress the total length of the optical system 10 can be achieved for incident light, and meanwhile, the principal plane of the optical system 10 is further away from the imaging plane Si, so as to enhance the telephoto imaging function of the optical system 10.

f12 The optical system 10 has the advantages that the lens group formed by the first lens element L1 and the second lens element L2 can better ensure that the optical system 10 has reasonable positive refractive power, the converging capability of the first lens element L1 and the second lens element L2 to light rays is enhanced, aberration generated by the first lens element L1 and the second lens element L2 is further corrected, and therefore high-quality imaging quality is obtained, in addition, the total length of the optical system 10 is favorably compressed, and the telephoto imaging function of the optical system 10 is further enhanced.

f4×r10/f5= -4.74mm, the refractive power of the fourth lens element L4 and the refractive power of the fifth lens element L5 are reasonably distributed, so that the spherical aberration of the optical system 10 is effectively balanced, and meanwhile, the image side surface of the fifth lens element L5 is concave at the paraxial region 101 and is bent towards the imaging surface Si side of the optical system 10, which is favorable for converging the central field-of-view light (i.e., the light at the center of the field-of-view) on the imaging surface Si, and is favorable for guiding the marginal field-of-view light (i.e., the light at the edge of the field-of-view) to the imaging surface Si, which effectively reduces the refractive angle of the marginal field-of-view light entering the photosensitive element, and improves the relative brightness of the image received by the photosensitive element, so that the image on the imaging surface Si is uniform and clear.

The thickness of each lens is properly configured, so that the optical system 10 is more compact, the requirement of miniaturized design of the optical system 10 is met, meanwhile, each lens is ensured to have proper thickness, insufficient strength caused by over-thinness of each lens is avoided, breakage is not easy to occur when each lens is assembled, the manufacturing yield of the optical system 10 is ensured, and the assembly of the optical system 10 is reduced, so that the manufacturing cost is low.

Further, CT1 = 2.04mm has guaranteed the thickness of first lens L1, and first lens L1 is as the lens that is closest to the object side, and is comparatively sensitive to external environment change, has had sufficient thickness through controlling first lens L1, has effectively improved first lens L1's structural strength, has strengthened first lens L1's resistance to external environment, avoids causing the phenomenon of breaking of first lens L1 under the impact of external world promptly better, has played better guard effect to whole optical system 10, improves the reliability that optical system 10 used.

(f1×r1)/(f2×r4) = -0.86, by reasonably controlling the radii of curvature of the object-side surface S1 of the first lens element L1 and the object-side surface S3 of the second lens element L2, the first lens element L1 and the second lens element L2 have reasonable surface shapes, and the refractive power of the first lens element L1 and the refractive power of the second lens element L2 are reasonably matched, so that reasonable convergence of incident light can be achieved to compress the total length of the optical system 10, the first lens element L1 and the second lens element L2 have opposite refractive powers, and the positive and negative lens element collocations can cancel each other to generate aberration, so that positive spherical aberration and negative spherical aberration generated in the optical system 10 cancel each other, thereby effectively preventing the first lens element L1 and the second lens element L2 from generating aberration which is difficult to correct, and improving imaging quality.

The radial dimension of the fifth lens L5 is reasonably controlled by SD52/CT 5=3.69, which is favorable for controlling the outer diameter dimension of the optical system 10, avoiding the optical system 10 having a large aperture, and reasonably controlling the thickness of the fifth lens L5, and favorable for reducing the thickness of the fifth lens L5 on the optical axis 101, thereby promoting the miniaturization development of the optical system 10, meanwhile, the surface shape of the fifth lens L5 is reasonably controlled, improving the lens molding yield of the fifth lens L5, and in addition, the fifth lens L5 is used as the lens closest to the imaging surface Si, which is favorable for better converging the light on the imaging surface Si due to the reasonable surface shape design, thereby improving the imaging quality.

The degree of deflection of the light passing through the third lens L3 and the fourth lens L4 can be controlled by nd3= 1.639 and nd4=1.635, which is beneficial to strengthening the aberration correction capability of the third lens L3 and the fourth lens L4, i.e. effectively correcting the aberration generated by the first lens L1 and the second lens L2, reducing the correction pressure of the fifth lens L5, and balancing the chromatic aberration generated by the optical system 10.

The ratio of the radius of curvature of the object side surface S9 of the fifth lens element L5 at the paraxial region 101 to the radius of curvature of the image side surface S10 of the fifth lens element L5 at the paraxial region 101 is controlled within a reasonable range, so that the problem that the shape of the fifth lens element L5 is too curved to be difficult to mold is avoided, and the lens molding yield of the fifth lens element L5 is improved; and the reasonable surface design of the fifth lens L5 is beneficial to enabling the light passing through the object lens to be better converged on the imaging surface Si, so that the imaging quality is improved.

ET 4/(|sag 41|+|sag 42|) =1.62, the ratio between the edge thickness of the fourth lens L4 and the sum of the sagittal absolute values of the object side surface S7 and the image side surface of the fourth lens L4 is reasonably controlled, so that the thickness of the fourth lens L4 is proper, the lens is positioned in the middle of the optical system 10, the design space in the optical system 10 is reasonable, the reduction of the total optical length of the optical system 10 is facilitated, the workability of the fourth lens L4 is improved, and the design and assembly sensitivity is reduced.

Fig. 2 includes a longitudinal spherical aberration diagram, an astigmatic curve diagram, and a distortion diagram of the optical system 10 in the first embodiment, wherein the astigmatic curve diagram and the distortion diagram have a reference wavelength of 587.6nm.

The longitudinal aberration plot (Longitudinal Spherical Aberration) exhibits a focus offset after passing light of different wavelengths through the lens. The ordinate of the longitudinal aberration diagram represents the normalized pupil coordinates (Normalized Pupil Coordinator) from the pupil center to the pupil edge, and the abscissa along the X-axis direction represents the distance (in mm) from the imaging plane to the intersection of the light ray and the optical axis. As can be seen from the longitudinal aberration graphs, the degree of focus deviation of the light rays of each wavelength in the first embodiment tends to be uniform, and the diffuse spots or the halos in the imaging picture are effectively suppressed.

An astigmatic diagram (Astigmatic Field Curves) in which the abscissa in the X-axis direction represents the focus offset and the ordinate in the Y-axis direction represents the image height in mm, and in which the S-curve represents the sagittal field curvature at 587.6nm and the T-curve represents the meridional field curvature at 587.6 nm. As can be seen from the figure, the field curvature of the optical system is smaller, the field curvature of most fields is controlled within 0.020mm, the curvature of the image plane is effectively suppressed, the difference between the sagittal field curvature and the meridional field curvature in each field is smaller, and the astigmatism of each field is better controlled, so that the center to the edge of the field of the optical system 10 can be seen to have clear imaging.

A Distortion curve (Distortion) in which the abscissa along the X-axis direction represents focus shift, the ordinate along the Y-axis direction represents image height in mm, the Distortion curve represents Distortion magnitude values corresponding to different image height positions, the maximum Distortion of the optical system 10 having the wide-angle characteristic is controlled to be about 1.4%, and the degree of Distortion is well controlled.

Second embodiment

Referring to fig. 3 and 4, in the second embodiment, a stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with positive refractive power, a fourth lens L4 with positive refractive power, and a fifth lens L5 with negative refractive power are provided. The surface profile of each lens surface in the optical system 10 is as follows:

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

The object side surface S9 of the fifth lens element L5 is concave at a paraxial region, and the image side surface S10 is concave at a paraxial region; the object side surface S9 is concave at the circumference and the image side surface S10 is convex at the circumference.

In addition, the parameters of each lens of the optical system 10 in the second embodiment are shown in tables 3 and 4, wherein the definitions of each structure and parameter can be obtained in the first embodiment, and the description thereof is omitted herein.

TABLE 3 Table 3

TABLE 4 Table 4

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

as can be seen from the aberration diagrams in fig. 4, the longitudinal spherical aberration, field curvature, astigmatism and distortion of the optical system 10 are well controlled, wherein the focal offset corresponding to the longitudinal spherical aberration at each wavelength is small, the meridional field curvature and the sagittal field curvature at each view field are controlled within 0.0125mm, the curvature of the image plane is well suppressed, the astigmatism is reasonably regulated, the maximum distortion is controlled to be about 1.4%, and the distortion is very effectively suppressed for a wide-angle system.

Third embodiment

Referring to fig. 5 and 6, in the third embodiment, a stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with positive refractive power, a fourth lens L4 with positive refractive power, and a fifth lens L5 with negative refractive power are provided. The surface profile of each lens surface in the optical system 10 is as follows:

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

The third lens element L3 has a convex object-side surface S5 at a paraxial region and a convex image-side surface S6 at a paraxial region; the object side surface S5 is concave at the circumference and the image side surface S6 is convex at the circumference.

The fourth lens element L4 has a convex object-side surface S7 at a paraxial region and a convex image-side surface S8 at a paraxial region; the object side surface S7 is convex at the circumference, and the image side surface S8 is convex at the circumference.

In addition, the parameters of each lens of the optical system 10 in the third embodiment are shown in tables 5 and 6, wherein the definitions of each structure and parameter can be obtained in the first embodiment, and the description thereof is omitted herein.

TABLE 5

TABLE 6

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

as can be seen from the aberration diagrams in fig. 6, the longitudinal spherical aberration, field curvature, astigmatism and distortion of the optical system 10 are well controlled, wherein the focal offset corresponding to the longitudinal spherical aberration at each wavelength is small, the meridional field curvature and the sagittal field curvature at each view field are controlled within 0.015mm, the curvature of the image plane is well suppressed, the astigmatism is reasonably regulated, the maximum distortion is controlled to be about 1.4%, and the distortion is very effectively suppressed for a wide-angle system.

Fourth embodiment

Referring to fig. 7 and 8, in the fourth embodiment, a stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with negative refractive power, a fourth lens L4 with positive refractive power, and a fifth lens L5 with negative refractive power are provided. The surface profile of each lens surface in the optical system 10 is as follows:

The fourth lens element L4 has a convex object-side surface S7 at a paraxial region and a convex image-side surface S8 at a paraxial region; the object side surface S7 is concave at the circumference and the image side surface S8 is convex at the circumference.

In addition, the parameters of each lens of the optical system 10 in the fourth embodiment are given in tables 7 and 8, wherein the definition of each structure and parameter can be obtained in the first embodiment, and the description thereof is omitted herein.

TABLE 7

TABLE 8

/>

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

as can be seen from the aberration diagrams in fig. 8, the longitudinal spherical aberration, field curvature, astigmatism and distortion of the optical system 10 are well controlled, wherein the focal offset corresponding to the longitudinal spherical aberration at each wavelength is small, the meridional field curvature and the sagittal field curvature at each view field are controlled within 0.014mm, the curvature of the image plane is well suppressed, the astigmatism is reasonably regulated, the maximum distortion is controlled to be about 1.4%, and the distortion is very effectively suppressed for a wide-angle system.

Fifth embodiment

Referring to fig. 9 and 10, in the fifth embodiment, a stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with negative refractive power, a fourth lens L4 with negative refractive power, and a fifth lens L5 with positive refractive power are provided. The surface profile of each lens surface in the optical system 10 is as follows:

The third lens element L3 has a concave object-side surface S5 at a paraxial region and a convex image-side surface S6 at a paraxial region; the object side surface S5 is concave at the circumference and the image side surface S6 is convex at the circumference.

In addition, the parameters of each lens of the optical system 10 in the fifth embodiment are shown in tables 9 and 10, wherein the definition of each structure and parameter can be obtained in the first embodiment, and the description thereof is omitted herein.

TABLE 9

Table 10

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

as can be seen from the aberration diagrams in fig. 10, the longitudinal spherical aberration, field curvature, astigmatism and distortion of the optical system 10 are well controlled, wherein the focal offset corresponding to the longitudinal spherical aberration at each wavelength is small, the meridional field curvature and the sagittal field curvature at each view field are controlled within 0.070mm, the curvature of the image plane is well suppressed, the astigmatism is reasonably regulated, the maximum distortion is controlled to be about 0.6%, and the distortion is very effectively suppressed for a wide-angle system.

Sixth embodiment

Referring to fig. 11 and 12, in the sixth embodiment, a stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with negative refractive power, a fourth lens L4 with positive refractive power, and a fifth lens L5 with negative refractive power are provided. The surface profile of each lens surface in the optical system 10 is as follows:

The fourth lens element L4 has a concave object-side surface S7 at a paraxial region and a convex image-side surface S8 at a paraxial region; the object side surface S7 is convex at the circumference, and the image side surface S8 is convex at the circumference.

The fifth lens element L5 has a convex object-side surface S9 at a paraxial region and a concave image-side surface S10 at a paraxial region; the object side surface S9 is convex at the circumference and the image side surface S10 is concave at the circumference.

In addition, the parameters of each lens of the optical system 10 in the sixth embodiment are given in tables 11 and 12, wherein the definition of each structure and parameter can be obtained in the first embodiment, and the description thereof is omitted herein.

TABLE 11

Table 12

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

as can be seen from the aberration diagrams in fig. 12, the longitudinal spherical aberration, field curvature, astigmatism and distortion of the optical system 10 are well controlled, wherein the focal offset corresponding to the longitudinal spherical aberration at each wavelength is small, the meridional field curvature and the sagittal field curvature at each view field are controlled within 0.010mm, the curvature of the image plane is well suppressed, the astigmatism is reasonably regulated, the maximum distortion is controlled to be about 1.4%, and the distortion is very effectively suppressed for a wide-angle system.

Referring to fig. 13, in an embodiment of the present application, an image capturing module 20 is provided, the image capturing module 20 includes a reflective prism 21, a photosensitive element 22 and the optical system 10 described above, the reflective prism 21 is disposed on an object side of the optical system 10, that is, the reflective prism 21 participates in the optical path transmission of the optical system 10, however, the reflective prism 21 may also be disposed on an image side, the number of reflective prisms 21 may be plural, and the photosensitive element 22 is disposed on the image side of the optical system 10. The photosensitive element 22 may be a CCD (Charge Coupled Device ) or CMOS (Complementary Metal Oxide Semiconductor, complementary metal oxide semiconductor). Generally, when assembled, the imaging surface Si of the optical system 10 coincides with the photosensitive surface of the photosensitive element 22, and the shape of the effective pixel area on the photosensitive surface is generally rectangular, and the maximum field angle corresponding to the diagonal direction of the rectangular effective pixel area is the maximum field angle of the optical system 10.

The miniaturized optical system 10 is beneficial to compressing the volume of the camera module 20, the miniaturized design of the camera module 20 is beneficial to, meanwhile, the periscope lens is jointly formed through the cooperation arrangement of the reflecting prism 21 and the optical system 10, the reflecting prism 21 turns the transmission path of incident light, the turned light is made to enter the optical system 10 and the image sensor 22 along the optical total length extending direction (namely the arrangement direction of each lens) of the optical system 10, the periscope function of the periscope lens is realized, the long focal length of the periscope lens is beneficial to realizing the telephoto function, wherein the incident direction of the incident light is perpendicular to the optical total length extending direction of the optical system 10, the oversized influence of the optical total length of the optical system 10 on the thickness design of the camera module 20 in the incident direction of the incident light is avoided, the thickness of the camera module 20 in the incident direction of the incident light is beneficial to shortening the thickness of the camera module 20 in the direction of the incident light, the size of the camera module is reduced, the camera module is made to develop towards the miniaturized direction, and the periscope function is realized.

In some embodiments, the image capturing module 20 includes an infrared filter disposed between the fifth lens element L5 and the photosensitive element 22, and the infrared cut filter 110 is used for filtering infrared light.

Referring to fig. 13 and 14, some embodiments of the present application further provide an electronic device 30, where the camera module 20 is applied to the electronic device 30 to enable the electronic device 30 to have a camera function. Specifically, the electronic device 30 includes a fixing member 310, and the camera module 20 is mounted on the fixing member 310, where the fixing member 310 may be a display screen, a touch display screen, a circuit board, a middle frame, a rear cover, and the like. The electronic device 30 may be, but is not limited to, a smart phone, a smart watch, smart glasses, an electronic book reader, a vehicle-mounted camera device, a monitoring device, a drone, a medical device (e.g., an endoscope), a tablet computer, a biometric device (e.g., a fingerprint recognition device or a pupil recognition device, etc.), a PDA (Personal Digital Assistant, a personal digital assistant), a drone, etc. By adopting the camera module 20, the size and the volume of the electronic equipment 30 are reduced, the electronic equipment 30 has the characteristic of miniaturization, and meanwhile, the periscope camera function of the electronic equipment 30 is realized through the periscope lens of the camera module 20.

It should be noted that, set up traditional module of making a video recording in the smart mobile phone, because traditional module of making a video recording is perpendicular to smart mobile phone back and places, promptly photosensitive element is parallel with the smart mobile phone back, makes the extending direction of the optical total length of optical system and the extending direction of the thickness of smart mobile phone parallel, leads to the thickness design of smart mobile phone to be limited. In some embodiments, when the camera module 20 of the present application is disposed on a smart phone, the periscope lens in the camera module 20 is disposed parallel to the back of the smart phone, so that the photosensitive element 21 is perpendicular to the back of the smart phone 22, so that the length space of the accommodated optical system 10 is greatly increased, and then the light entering the camera module 20 is bent by 90 ° through the reflecting prism 21 and then enters the optical system 10 and the image sensor 22 respectively, so that the influence of the optical length of the optical system on the thickness design of the smart phone can be reduced, and the requirements of thinning the smart phone are further met.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

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

a third lens element with refractive power;

a fourth lens element with refractive power;

and the optical system satisfies the following conditional expression:

0.75mm<ET3+ET5+ET7+ET9<2.00mm；

0.80<TT/BFL<1.50；

0.85<SD52/CT5<3.75；

1.50<ET4/(|SAG41|+|SAG42|)<22.00；

wherein ET3 is the distance in the optical axis direction between the maximum effective aperture of the first lens object-side surface and the maximum effective aperture of the second lens object-side surface, ET5 is the distance in the optical axis direction between the maximum effective aperture of the second lens object-side surface and the maximum effective aperture of the third lens object-side surface, ET7 is the distance in the optical axis direction between the maximum effective aperture of the third lens image-side surface and the maximum effective aperture of the fourth lens object-side surface, ET9 is the distance in the optical axis direction between the maximum effective aperture of the fourth lens image-side surface and the maximum effective aperture of the fifth lens object-side surface, TT is the distance in the optical axis direction between the object-side surface of the first lens and the image-side surface of the fifth lens, BFL is the distance in the optical axis direction between the image-side surface of the fifth lens object-side surface and the image-side surface of the optical system, ET 52 is the distance in the optical axis direction between the maximum effective aperture of the fourth lens object-side surface and the fourth lens object-side surface, ET9 is the distance in the optical axis direction between the maximum effective aperture of the fourth lens object-side surface and the fourth lens object-side surface, and the fourth lens object-side surface is the maximum effective aperture of 5, and the image-side surface of the fourth lens object-side surface is the maximum distance in the image-plane 4, and SAG is the maximum distance in the image-plane of the image-side surface of the fourth lens object-side surface.

2. The optical system of claim 1, further comprising a stop disposed on an object side of the first lens.

3. The optical system of claim 1, wherein the optical system satisfies the conditional expression:

0.60<f12/f<1.40；

wherein f12 is a combined focal length of the first lens and the second lens, and f is an effective focal length of the optical system.

4. The optical system of claim 1, wherein the optical system satisfies the conditional expression:

-45.00mm<f4R10/f5<-2.00mm；

wherein f4 is an effective focal length of the fourth lens element, f5 is an effective focal length of the fifth lens element, and R10 is a radius of curvature of an image-side surface of the fifth lens element at an optical axis.

5. The optical system of claim 1, wherein the optical system satisfies the conditional expression:

0.80<(CT1+CT2)/(CT3+CT4+CT5)<1.60；

wherein, CT1 is the thickness of the first lens on the optical axis, CT2 is the thickness of the second lens on the optical axis, CT3 is the thickness of the third lens on the optical axis, and CT4 is the thickness of the fourth lens on the optical axis.

6. The optical system of claim 1, wherein the optical system satisfies the conditional expression:

-1.50<(f1R1)/(f2/>R4)<-0.10；

7. An image pickup module, comprising a reflecting prism, a photosensitive element and the optical system of any one of claims 1 to 6, wherein the reflecting prism is disposed on an object side of the optical system, and the photosensitive element is disposed on an image side of the optical system.

8. An electronic device, comprising a fixing member and the camera module set according to claim 7, wherein the camera module set is disposed on the fixing member.