CN114675407A

CN114675407A - Optical system, lens module and electronic equipment

Info

Publication number: CN114675407A
Application number: CN202210584887.8A
Authority: CN
Inventors: 张洛彬; 华露; 杨健; 李明
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2022-05-27
Filing date: 2022-05-27
Publication date: 2022-06-28
Anticipated expiration: 2042-05-27
Also published as: CN114675407B

Abstract

The invention relates to an optical system, a lens module and an electronic device. The optical system includes, 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 at paraxial region; a second lens element with negative refractive power having a concave image-side surface at paraxial region; a third lens element with positive refractive power having a convex object-side surface and a concave image-side surface; a fourth lens element with refractive power; a fifth lens element with refractive power; the optical system satisfies: f/tan (FOV) is less than or equal to 11mm and less than or equal to 13 mm. The optical system can obtain enough light when shooting remote objects, thereby realizing the imaging effect of long focal length, miniaturization and high quality.

Description

Optical system, lens module and electronic equipment

Technical Field

The present invention relates to the field of camera shooting, and in particular, to an optical system, a lens module, and an electronic apparatus.

Background

In recent years, with the rapid development of camera shooting technology, hardware and software technologies related to electronic devices such as mobile phones, tablet computers, electronic readers and the like are rapidly developed, and the market demand for lenses applied to electronic devices such as mobile phones and the like is increasing. Nowadays, in order to adapt to different environments and different functional requirements, various characteristics of the lens need to be continuously enhanced, and the number of the lenses carried by a single mobile phone is also continuously increased. In addition, the performance of the image sensor portion directly collocated with the lens is also continuously improved, and in order to adapt to the development of the image sensor, the lens portion also needs to achieve the effect of realizing high-quality imaging. Under the trend of such market environment, the design difficulty of the lens of the electronic equipment such as the mobile phone is only increased but not reduced. However, the lens in the existing electronic device generally has a problem of insufficient shooting range when shooting a distant scene, and is difficult to satisfy user experience.

Disclosure of Invention

Accordingly, it is desirable to provide an optical system, a lens module and an electronic device, which can solve the problem of insufficient shooting range of the conventional lens when shooting a distant scene.

An optical system includes five lens elements with refractive power, 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 at paraxial region;

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

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

a fourth lens element with refractive power;

a fifth lens element with refractive power;

and the optical system satisfies the following conditional expression:

11mm≤f/tan(FOV)≤13mm；

wherein f is an effective focal length of the optical system, and the FOV is a maximum field angle of the optical system.

In the optical system, the first lens element with positive refractive power has a convex object-side surface at a paraxial region, which is helpful for collecting light and converging the light, thereby being beneficial to shortening the total length of the optical system and realizing the miniaturization design of the optical system. The second lens element with negative refractive power has a concave image-side surface at paraxial region, which is favorable for balancing aberration generated by the first lens element and improving on-axis image quality of the optical system. The third lens element with positive refractive power has a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region, and is favorable for further shortening the total length of the optical system and correcting aberration of the optical system. The object-side lens group (i.e., the first lens element to the third lens element) is matched with the refractive powers of the fourth lens element and the fifth lens element, so as to effectively control the effective focal length of the optical system, thereby being beneficial to realizing the telephoto characteristic of the optical system.

When the conditional expression is satisfied, the ratio between the effective focal length of the optical system and the tangent value of the field angle can be reasonably configured, and the reasonable field angle is favorably possessed under the requirement of keeping the telephoto system, so that a better shooting range can be obtained when telephoto shooting is carried out, the light flux amount of the optical system and the utilization rate of light are simultaneously improved, and the imaging quality is favorably improved. When the effective focal length of the optical system is lower than the lower limit of the conditional expression, the effective focal length of the optical system is too short, the field angle is too large, and light rays in the marginal field cannot be effectively converged, so that the imaging quality at the edge of the field is poor. If the upper limit of the above conditional expression is exceeded, the angle of view of the optical system is too small, and the ability of each field of view to receive light becomes weak, and the requirement for wide-range shooting cannot be satisfied. The optical system has the refractive power and the surface shape characteristics and meets the conditional expression, and can obtain enough light when shooting remote objects, so that the imaging effect of long focal length, miniaturization and high quality is realized.

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

0.85≤CT3/sag31≤1.5；

wherein CT3 is the thickness of the third lens on the optical axis, i.e. the center thickness of the third lens, and sag31 is the distance from the maximum effective aperture of the object-side surface of the third lens to the intersection point of the object-side surface of the third lens and the optical axis in the optical axis direction, i.e. the rise of the object-side surface of the third lens at the maximum effective aperture. When the conditional expression is met, the ratio of the central thickness to the rise of the object side surface of the third lens can be reasonably configured, so that the shape of the third lens can be reasonably controlled, and good conditions can be provided for processing and assembling the third lens; meanwhile, the third lens is beneficial to correcting the field curvature generated by the object side lens (namely the first lens and the second lens), so that the field curvature aberration of the optical system is balanced, and the imaging quality of the optical system is further beneficial to being improved. If the lower limit of the above conditional expression is less than the lower limit of the conditional expression, the surface shape of the third lens is too complicated, which is disadvantageous for the engineering production of the third lens. If the upper limit of the above conditional expression is exceeded, the surface shape of the third lens is too gentle, and it becomes difficult to balance the curvature of field of the optical system, resulting in poor performance of the optical system.

2.7≤f/f1+f/|f2|≤3.4；

wherein f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens. When the condition is met, the sum of the ratio of the effective focal length of the optical system to the effective focal lengths of the first lens and the second lens can be reasonably distributed, so that the contribution of the refractive power of the first lens and the second lens in the system is reasonably distributed, the overlarge degree of the surface type bending of the first lens and the surface type bending of the second lens are favorably avoided, the processing and the assembly of the first lens and the second lens are favorably realized, the serious aberration generated when the first lens and the second lens collect light rays is favorably avoided, and the imaging quality of the optical system is favorably improved; meanwhile, the contribution of the refractive power of the first lens and the second lens in the system is controlled, and the deflection angle of marginal field light rays passing through the first lens and the second lens is favorably controlled, so that the marginal field light rays are effectively converged, the illumination of an imaging surface is favorably improved, the phenomena of dark angles and the like are avoided, and the stability of the system is improved.

1.2≤sd11/sd31≤1.6；

wherein sd11 is the maximum effective half aperture of the object-side surface of the first lens, and sd31 is the maximum effective half aperture of the object-side surface of the third lens. When satisfying above-mentioned conditional expression, the ratio of the most effective half bore that can rational distribution first lens and the most effective half bore of third lens, the difference of the most effective half bore of avoiding first lens and third lens is too big, the optical system's of being convenient for equipment promotes the yield, be favorable to restricting the scope of the incident ray through first lens and third lens simultaneously, remain the high image light of middle quality, reject the relatively poor stray light of marginal quality, thereby reduce optical system's off-axis aberration, and then promote optical system's image quality.

3.2≤TTL/ImgH≤3.4；

wherein, TTL is a distance on an optical axis from an object-side surface of the first lens element to an image plane of the optical system, that is, a total optical length of the optical system, and ImgH is a half of an image height corresponding to a maximum field angle of the optical system. When the condition formula is met, the ratio of the total optical length of the optical system to the half-image height can be reasonably distributed, so that the total optical length of the optical system is favorably shortened, the miniaturized design is realized, the size of an imaging surface of the optical system can be improved, and the imaging quality of the optical system is favorably improved.

0.7≤sag52/sag51≤1.2；

wherein sag51 is a distance in the optical axis direction from the maximum effective aperture of the object-side surface of the fifth lens element to the intersection point of the object-side surface of the fifth lens element and the optical axis, that is, a rise of the object-side surface of the fifth lens element at the maximum effective aperture, and sag52 is a distance in the optical axis direction from the maximum effective aperture of the image-side surface of the fifth lens element to the intersection point of the image-side surface of the fifth lens element and the optical axis, that is, a rise of the image-side surface of the fifth lens element at the maximum effective aperture. When satisfying above-mentioned conditional expression, can retrain the crooked degree of the face type of the object side face of fifth lens and image side face, be favorable to avoiding the face type too complicated to lead to being difficult to processing, still be favorable to guaranteeing that the chief ray incides to the formation of image face with less incident angle simultaneously to be favorable to promoting the imaging quality of system. Below the lower limit of the conditional expression, the object-side edge height of the fifth lens is too large, and above the upper limit of the conditional expression, the image-side edge height of the fifth lens is too large, which results in too large an inclination angle of the surface of the fifth lens, complicates the surface shape, increases the manufacturing difficulty of the fifth lens, and affects the processing and assembly of the fifth lens; in addition, the inclination angle at the maximum effective aperture of the fifth lens is too large, which leads to too large incident angle of the marginal field of view light to the imaging surface, so that the marginal field of view light cannot be effectively converged, thereby being not beneficial to improving the imaging quality of the system.

1.5-2.9 (CT2+ CT3+ CT4)/(CT23+ CT 34); and/or the presence of a gas in the atmosphere,

2.2≤BFL/(CT4+CT5)≤4.1；

wherein, CT2 is a thickness of the second lens element on an optical axis, that is, a center thickness of the second lens element, CT3 is a thickness of the third lens element on the optical axis, that is, a center thickness of the third lens element, CT4 is a thickness of the fourth lens element on the optical axis, that is, a center thickness of the fourth lens element, CT23 is a distance between an image-side surface of the second lens element and an object-side surface of the third lens element in an optical axis direction, and CT34 is a distance between the image-side surface of the third lens element and the object-side surface of the fourth lens element in the optical axis direction. When the condition formula is met, the central thickness of the second lens, the third lens and the fourth lens can be reasonably distributed, and the air intervals among the central thickness and the central thickness of the fourth lens are ensured, so that enough space deflection light rays exist among the second lens, the third lens and the fourth lens, the reduction of the deflection angle of the light rays in the refraction of the second lens to the fourth lens is facilitated, in addition, enough design and arrangement space exists between the second lens and the fourth lens, the reduction of tolerance sensitivity during lens assembly is facilitated, ghost images are prevented, and the miniaturization of an optical system is facilitated. When the lower limit of the above conditional expression is lower, the air space between the second lens and the third lens and between the third lens and the fourth lens is too large, resulting in insufficient compactness of the optical system, increasing the total length of the optical system, and making it difficult to keep the optical system small. When the upper limit of the conditional expression is exceeded, the central thicknesses of the second lens, the third lens and the fourth lens are too large, so that a ghost image is easy to appear in an optical system, and the imaging quality is poor.

The BFL is a shortest distance between an image-side surface of the fifth lens element and an image plane of the optical system in an optical axis direction, the CT4 is a thickness of the fourth lens element in the optical axis direction, that is, a central thickness of the fourth lens element, and the CT5 is a thickness of the fifth lens element in the optical axis direction, that is, a central thickness of the fifth lens element. When the conditional expressions are satisfied, the ratio of the back focus of the optical system to the sum of the thicknesses of the fourth lens and the fifth lens can be reasonably configured, which is beneficial to leaving enough matching space when the optical system and the photosensitive element are assembled, the sum of the central thickness of the fourth lens and the central thickness of the fifth lens is limited, which is beneficial to compensating the distortion generated by the object side lenses (namely, the first lens to the third lens) of the fourth lens, and simultaneously beneficial to manufacturing and molding the fourth lens and the fifth lens. When the lower limit of the above conditional expression is lower, the back focal length of the optical system is too short, which is disadvantageous in assembling between the optical system and the photosensitive element. When the upper limit of the conditional expression is exceeded, the central thicknesses of the fourth lens and the fifth lens are too small, which is not beneficial to the processing and manufacturing of the fourth lens and the fifth lens, and is also not beneficial to compensating the distortion of the object side lens of the fourth lens to the optical system, which affects the imaging effect of the optical system.

1.5≤f/EPD≤1.7；

wherein EPD is an entrance pupil diameter of the optical system. When the condition formula is satisfied, the ratio of the effective focal length of the optical system to the entrance pupil diameter can be reasonably configured, so that the optical system has a larger aperture, the size of the Airy spots of the optical system is reduced, the imaging quality of the optical system is improved, meanwhile, the light entering the entrance pupil diameter is sufficient, the dark angle of an imaging surface is avoided, and the shooting effect of the optical system in a weak light environment is improved. The larger the diameter of the entrance pupil, the smaller the f-number and the smaller the radius of the Airy spot; meanwhile, the reduction of the focal length can also reduce the diameter of the airy disk and reduce the volume of the system; however, if the value is less than the lower limit of the above conditional expression, the entrance pupil diameter is too large, which is disadvantageous to the convergence of the incident light and tends to introduce more aberrations. When the upper limit of the above conditional expression is exceeded, the diameter of the entrance pupil is too small, so that the incident light of the optical system is insufficient, and the imaging quality of the optical system in a low-light environment is reduced.

In one embodiment, the optical system further includes a turning prism, and the turning prism is disposed between an object plane of the optical system and an object-side surface of the first lens, and is configured to turn an object-side optical path of the first lens, and fold the optical path to facilitate a light and thin design.

A lens module includes a photosensitive element and the optical system described in any of the above embodiments, wherein the photosensitive element is disposed on an image side of the optical system. The lens module adopts the optical system, and can obtain enough light rays when shooting remote objects, thereby realizing the imaging effect of long focal length, miniaturization and high quality.

An electronic device comprises a shell and the lens module, wherein the lens module is arranged on the shell. The lens module is adopted in the electronic equipment, so that enough light can be obtained when long-distance objects are shot, and the imaging effect of long focal length, miniaturization and high quality is realized.

Drawings

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

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

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

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

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

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

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

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

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

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

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

FIG. 12 is a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system according to a sixth embodiment of the present application;

FIG. 13 is a schematic structural diagram of an optical system according to a seventh embodiment of the present application;

FIG. 14 is a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system according to a seventh embodiment of the present application;

FIG. 15 is a schematic view of an optical system according to an eighth embodiment of the present application;

fig. 16 is a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system in an eighth embodiment of the present application;

FIG. 17 is a schematic structural diagram of an optical system according to an embodiment of the present application;

fig. 18 is a schematic view of a lens module according to an embodiment of the present application;

fig. 19 is a schematic diagram of an electronic device in an embodiment of the application.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.

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

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

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

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

Referring to fig. 1, in some embodiments of the present application, the optical system 100 includes, in order from an object side to an image side along an optical axis 110, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5. Specifically, the first lens element L1 includes an object-side surface S1 and an image-side surface S2, the second lens element L2 includes an object-side surface S3 and an image-side surface S4, the third lens element L3 includes an object-side surface S5 and an image-side surface S6, the fourth lens element L4 includes an object-side surface S7 and an image-side surface S8, and the fifth lens element L5 includes an object-side surface S9 and an image-side surface S10. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are coaxially disposed, and an axis common to the lenses in the optical system 100 is an optical axis 110 of the optical system 100.

The first lens element L1 with positive refractive power has a convex object-side surface S1 near the optical axis, which is helpful for collecting light and converging light, so as to shorten the total length of the optical system 100 and to achieve a compact design of the optical system 100. The second lens element L2 with negative refractive power has a concave image-side surface S4 at a paraxial region, which is favorable for balancing the aberration generated by the first lens element and improving the on-axis image quality of the optical system 100. The third lens element L3 with positive refractive power has a convex object-side surface S5 at the paraxial region and a concave image-side surface S6 at the paraxial region, which is favorable for further shortening the total length of the optical system 100 and correcting the aberration of the optical system 100. The object-side lens group (i.e., the first lens element L1 to the third lens element L3) and the refractive powers of the fourth lens element L4 and the fifth lens element L5 can effectively control the effective focal length of the optical system 100, thereby being beneficial to realizing the telephoto characteristic of the optical system 100.

In addition, in some embodiments, the optical system 100 is provided with a stop, which may be disposed at the object side S9 of the fifth lens L5. In some embodiments, the optical system 100 further includes an infrared filter L6 disposed on the image side of the fifth lens L5. The infrared filter L6 includes an object side S11 and an image side S12. The ir filter L6 may be an ir cut filter, and is used to filter out interference light, so as to prevent the interference light from reaching the image plane of the optical system 100 and affecting normal imaging. Furthermore, the optical system 100 further includes an image forming surface S13 located on the image side of the fifth lens element L5, the image forming surface S13 is an image forming circular surface of the optical system 100, and incident light can be formed on the image forming surface S13 after being adjusted by the first lens element L1, the second lens element L2, the third lens element L3, the fourth lens element L4, and the fifth lens element L5.

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

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

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

Further, in some embodiments, the optical system 100 satisfies the conditional expression: f/tan (FOV) is less than or equal to 11mm and less than or equal to 13 mm; where f is the effective focal length of the optical system 100 and the FOV is the maximum field angle of the optical system 100. Specifically, f/tan (fov) may be: 11.165, 11.280, 11.318, 11.861, 11.875, 12.204, 12.280, 12.425, 12.522, 12.671 (units are all mm). When the above conditional expressions are satisfied, the ratio between the effective focal length of the optical system 100 and the tangent value of the field angle can be reasonably configured, which is beneficial to having a larger field angle under the requirement of maintaining a long-focus system, and improving the light-entering amount and the light utilization rate of the optical system 100, thereby being beneficial to improving the imaging quality. Below the lower limit of the above conditional expression, the effective focal length of the optical system 100 is too short, the field angle is too large, and the light in the edge field cannot be effectively converged, resulting in poor imaging quality at the edge of the field. If the upper limit of the above conditional expression is exceeded, the angle of view of the optical system 100 is too small, and the ability to receive light in each field of view becomes weak, and the requirement for wide-range shooting cannot be satisfied. Having the above-mentioned refractive power and surface shape characteristics and satisfying the above-mentioned conditional expressions, the optical system 100 can obtain sufficient light even when shooting a long-distance object, thereby realizing a long-focus, miniaturized, and high-quality imaging effect.

In some embodiments, the optical system 100 satisfies the conditional expression: CT3/sag31 is more than or equal to 0.85 and less than or equal to 1.5; CT3 is the thickness of the third lens element L3 on the optical axis 110, i.e., the center thickness of the third lens element L3, and sag31 is the distance from the maximum effective aperture of the object-side surface S5 of the third lens element L3 to the intersection point of the object-side surface S5 of the third lens element L3 and the optical axis 110 in the direction of the optical axis 110, i.e., the rise of the object-side surface S5 of the third lens element L3 at the maximum effective aperture. Specifically, CT3/sag31 may be: 0.879, 0.900, 0.923, 0.938, 1.058, 1.085, 1.123, 1.246, 1.343, 1.483. When the above conditional expressions are satisfied, the ratio of the center thickness to the rise of the object-side surface S5 of the third lens L3 can be reasonably controlled, which is beneficial to reasonably configuring the shape of the third lens L3, thereby being beneficial to providing good conditions for processing and assembling the third lens L3 and improving the imaging quality of the optical system 100; meanwhile, the third lens element L3 is favorable for correcting the curvature of field aberration generated by the object-side lens element (i.e., the first lens element L1 and the second lens element L2), so as to balance the curvature of field of the optical system 100, thereby being favorable for improving the imaging quality of the optical system 100. If the lower limit of the above conditional expression is less than the lower limit of the conditional expression, the surface shape of the third lens L3 is too complicated, which is disadvantageous for the engineering of the third lens L3. If the upper limit of the above conditional expression is exceeded, the surface shape of the third lens L3 is too gentle, and it becomes difficult to balance the curvature of field of the optical system 100, and the performance of the optical system 100 is poor. It should be noted that the rise at a certain point on the lens surface generally has a positive direction or a negative direction, specifically, when a perpendicular line perpendicular to the optical axis is drawn through the point, and the perpendicular line is located on the object side of the intersection point of the lens surface and the optical axis, the rise has a negative direction and can be represented by a negative value; when the vertical point is located on the image side of the intersection of the lens surface and the optical axis, the rise has a positive direction and can be represented by a positive value.

In some embodiments, the optical system 100 satisfies the conditional expression: f/f1+ f/| f2| -3.4 | -2.7; wherein f1 is the effective focal length of the first lens L1, and f2 is the effective focal length of the second lens L2. Specifically, f/f1+ f/| f2| may be: 2.790, 2.968, 3.016, 3.028, 3.059, 3.139, 3.188, 3.209, 3.265 and 3.341. When the above conditional expressions are satisfied, the sum of the ratios of the effective focal length of the optical system 100 to the effective focal lengths of the first lens L1 and the second lens L2 can be reasonably distributed, so that the contribution of the refractive power of the first lens L1 and the second lens L2 in the system can be reasonably distributed, the excessive degree of the surface curvature of the first lens L1 and the second lens L2 can be favorably avoided, the processing and the assembly of the first lens L1 and the second lens L2 are favorably realized, the serious aberration generated when the first lens L1 and the second lens L2 converge light rays can be favorably avoided, and the imaging quality of the optical system 100 can be favorably improved; meanwhile, the contribution of the refractive power of the first lens element L1 and the second lens element L2 in the system is controlled, and the deflection angles of the marginal field rays passing through the first lens element L1 and the second lens element L2 are also controlled, so that the field rays are effectively converged, the illumination of the imaging surface S13 is improved, the phenomena of dark corners and the like are avoided, and the system stability is improved.

In some embodiments, the optical system 100 satisfies the conditional expression: sd11/sd31 is more than or equal to 1.2 and less than or equal to 1.6; wherein sd11 is half of the maximum effective aperture of the object-side surface S1 of the first lens L1, and sd31 is half of the maximum effective aperture of the object-side surface S5 of the third lens L3. Specifically, sd11/sd31 can be: 1.263, 1.274, 1.302, 1.347, 1.352, 1.390, 1.404, 1.436, 1.486, 1.574. When satisfying above-mentioned conditional expression, half of the maximum effective bore that can rationally distribute first lens L1 and half of the maximum effective bore of third lens L3's ratio, the maximum effective bore difference of avoiding first lens L1 and third lens L3 is too big, be convenient for optical system 100's equipment and promote the yield, be favorable to restricting the scope through first lens L1 and third lens L3's incident ray simultaneously, the high image light of quality in the middle of keeping, reject the relatively poor stray light of marginal quality, thereby reduce optical system 100's off-axis aberration, and then promote optical system 100's imaging quality.

In some embodiments, the optical system 100 satisfies the conditional expression: TTL/ImgH is more than or equal to 3.2 and less than or equal to 3.4; wherein, TTL is a distance from the object-side surface S1 of the first lens element L1 to the image plane S13 of the optical system 100 on the optical axis 110, i.e., the total optical length of the optical system 100, and ImgH is half of the image height corresponding to the maximum field angle of the optical system 100. Specifically, TTL/ImgH may be: 3.269, 3.372, 3.281, 3.294, 3.300, 3.312, 3.330, 3.336, 3.345, 3.358. When the above conditional expressions are satisfied, the ratio of the total optical length of the optical system 100 to the half-image height can be reasonably distributed, so that the total optical length of the optical system 100 can be shortened, the miniaturization design is realized, the size of the imaging surface S13 of the optical system 100 can be improved, and the imaging quality of the optical system 100 can be improved.

In some embodiments, the optical system 100 satisfies the conditional expression: sag52/sag51 is more than or equal to 0.7 and less than or equal to 1.2; here, sag51 is a distance from the maximum effective aperture of the object-side surface S9 of the fifth lens L5 to the intersection point of the object-side surface S9 of the fifth lens L5 and the optical axis 110 in the direction of the optical axis 110, that is, a rise of the object-side surface S9 of the fifth lens L5 in the direction of the maximum effective aperture, and sag52 is a distance from the maximum effective aperture of the image-side surface S10 of the fifth lens L5 to the intersection point of the image-side surface S10 of the fifth lens L5 and the optical axis 110 in the direction of the optical axis 110, that is, a rise of the image-side surface S10 of the fifth lens L5 in the direction of the maximum effective aperture. Specifically, sag52/sag51 can be: 0.730, 0.776, 0.865, 0.884, 0.913, 0.932, 0.953, 1.033, 1.063, 1.104. When the conditional expressions are satisfied, the bending degree of the surface type of the object side surface S9 and the image side surface S10 of the fifth lens L5 can be constrained, which is beneficial to avoiding the difficulty in processing caused by too complicated surface type, and simultaneously, is beneficial to ensuring that the chief ray is incident to the imaging surface S13 at a smaller incident angle, thereby being beneficial to improving the imaging quality of the system. Below the lower limit of the above conditional expression, the rise of the object-side surface S9 of the fifth lens L5 is too large, and above the upper limit of the above conditional expression, the rise of the image-side surface S10 of the fifth lens L5 is too large, which results in too large an inclination angle of the surface of the fifth lens L5, complicates the surface shape, increases the manufacturing difficulty of the fifth lens L5, and affects the processing and assembly of the fifth lens L5; in addition, the too large inclination angle at the maximum effective aperture of the fifth lens element L5 will result in too large incident angle of the marginal field of view light to the imaging plane S13, so that the marginal field of view cannot be converged effectively, thereby being unfavorable for improving the imaging quality of the system.

In some embodiments, the optical system 100 satisfies the conditional expression: 1.5-2.9 (CT2+ CT3+ CT4)/(CT23+ CT 34); CT2 is a thickness of the second lens element L2 on the optical axis 110, i.e., a center thickness of the second lens element L2, CT3 is a thickness of the third lens element L3 on the optical axis 110, i.e., a center thickness of the third lens element L3, CT4 is a thickness of the fourth lens element L4 on the optical axis 110, i.e., a center thickness of the fourth lens element L4, CT23 is a distance between an image-side surface of the second lens element L2 and an object-side surface of the third lens element L3 on the optical axis 110, and CT34 is a distance between the image-side surface of the third lens element L3 and the object-side surface of the fourth lens element L4 on the optical axis 110. Specifically, (CT2+ CT3+ CT4)/(CT23+ CT34) may be: 1.552, 1.855, 2.010, 2.057, 2.084, 2.231, 2.369, 2.468, 2.755, 2.820. When the above conditional expressions are satisfied, the central thicknesses of the second lens L2, the third lens L3 and the fourth lens L4 and the air intervals among the central thicknesses can be reasonably distributed, so that sufficient space deflection light rays are provided among the second lens L2, the third lens L3 and the fourth lens L4, the reduction of the deflection angle of the light rays in the refraction of the second lens L2 to the fourth lens L4 is facilitated, in addition, sufficient design and arrangement space is provided among the second lens L2 to the fourth lens L4, the reduction of tolerance sensitivity in lens assembly is facilitated, ghost images are prevented, and the miniaturization of the optical system 100 is facilitated. When the lower limit of the above conditional expression is exceeded, the air space between the second lens L2 and the third lens L3, and between the third lens L3 and the fourth lens L4 is too large, resulting in insufficient compactness of the optical system 100, an increase in the total length of the optical system 100, and difficulty in keeping the optical system 100 small. When the upper limit of the above conditional expression is exceeded, the center thicknesses of the second lens L2, the third lens L3, and the fourth lens L4 are too large, and the optical system 100 is prone to ghost images, resulting in poor imaging quality.

In some embodiments, the optical system 100 satisfies the conditional expression: BFL/(CT4+ CT5) is more than or equal to 2.2 and less than or equal to 4.1; BFL is the shortest distance from the image-side surface of the fifth lens element L5 to the image plane S13 of the optical system 100 in the direction of the optical axis 110, CT4 is the thickness of the fourth lens element L4 on the optical axis 110, i.e. the center thickness of the fourth lens element L4, and CT5 is the thickness of the fifth lens element L5 on the optical axis 110, i.e. the center thickness of the fifth lens element L5. Specifically, BFL/(CT4+ CT5) may be: 2.277, 2.463, 3.117, 3.193, 3.320, 3.504, 3.657, 3.809, 4.036, 4.072. When the above conditional expressions are satisfied, the ratio of the back focus of the optical system 100 to the sum of the thicknesses of the fourth lens L4 and the fifth lens L5 can be reasonably configured, which is favorable for leaving enough fitting space for assembling the optical system 100 and the photosensitive element, the sum of the central thickness of the fourth lens L4 and the central thickness of the fifth lens L5 is limited, which is favorable for compensating the distortion generated by the object side lenses (i.e., the first lens L1 to the third lens L3) of the fourth lens L4, and is favorable for manufacturing and molding the fourth lens L4 and the fifth lens L5. When the lower limit of the above conditional expression is lower, the back focal length of the optical system 100 is too short, which is disadvantageous in assembling between the optical system 100 and the photosensitive element. If the upper limit of the above conditional expression is exceeded, the central thicknesses of the fourth lens L4 and the fifth lens L5 are too small, which is not favorable for the manufacturing of the fourth lens L4 and the fifth lens L5, and is also not favorable for compensating the distortion generated by the object side lens of the fourth lens L4, which affects the imaging effect of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: f/EPD is more than or equal to 1.5 and less than or equal to 1.7; where EPD is the entrance pupil diameter of the optical system 100. Specifically, the f/EPD may be: 1.530, 1.564, 1.565, 1.573, 1.582, 1.596, 1.600, 1.625, 1.650, 1.690. When the above conditional expressions are satisfied, the effective focal length of the optical system 100 and the ratio of the effective focal length to the same diameter can be reasonably configured, so that the optical system 100 has a large aperture, the size of the airy disk of the optical system 100 is reduced, the improvement of the imaging quality of the optical system 100 is facilitated, meanwhile, the light entering the diameter of the entrance pupil is sufficient, the dark angle of the imaging surface S13 is avoided, and the shooting effect of the optical system 100 in a low-light environment is improved. The larger the diameter of the entrance pupil, the smaller the f-number and the smaller the radius of the airy disk; meanwhile, the reduction of the focal length can also reduce the diameter of the airy disk and reduce the volume of the system; however, if the lower limit of the above conditional expression is exceeded, the entrance pupil diameter becomes too large, which is disadvantageous in converging the incident light beam and tends to introduce more aberrations. If the upper limit of the above conditional expression is exceeded, the entrance pupil diameter is too small, so that the incident light of the optical system 100 is insufficient, and the imaging quality of the optical system 100 in a low-light environment is degraded.

Further, referring to fig. 17, in some embodiments, the optical system 100 further includes a turning prism L7, the turning prism L7 is disposed between the object plane of the optical system 100 and the object side surface S1 of the first lens L1, and is configured to turn the object-side optical path of the first lens L1, and the optical path is folded to facilitate a light and thin design, so that the optical system 100 is suitable for a periscopic lens, and a focusing function at different shooting object distances can be achieved without increasing the thickness of the lens; meanwhile, when the optical system 100 is used in an electronic device, the dimension of the optical system 100 on the axis is changed from the thickness direction dimension of the electronic device to the other direction dimension, and the optical system 100 can be prevented from increasing the thickness of the body of the electronic device. Specifically, the turning prism L7 may be a prism structure capable of turning the optical path, such as a right-angle prism, an equilateral triangular prism, or a pentagonal prism. Preferably, in some embodiments, the turning prism L7 is a right-angle prism, so that when the optical system 100 is applied to an electronic device, the on-axis dimension of the optical system 100 can be changed from the thickness direction dimension to the length direction dimension of the electronic device, thereby improving the lightness and thinness of the electronic device.

It should be noted that in some embodiments, the optical system 100 may match a photosensitive element having a rectangular photosensitive surface, and the imaging surface S13 of the optical system 100 coincides with the photosensitive surface of the photosensitive element. At this time, the effective pixel region on the imaging plane S13 of the optical system 100 has a horizontal direction and diagonal directions, the maximum angle of view can be understood as the maximum angle of view in the diagonal direction of the optical system 100, and ImgH can be understood as half the length in the diagonal direction of the effective pixel region on the imaging plane of the optical system 100.

The reference wavelengths of the above effective focal length values are all 555 nm.

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

First embodiment

Referring to fig. 1 and 2, fig. 1 is a schematic structural diagram of the optical system 100 in the first embodiment, and the optical system 100 includes, in order from an object side to an image side, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with positive refractive power, and a fifth lens element L5 with positive refractive power. Fig. 2 is a graph of longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the first embodiment, sequentially from left to right, wherein the reference wavelength of the astigmatism graph and the distortion graph is 555nm, and the other embodiments are the same.

The object-side surface S1 of the first lens element L1 is convex at a paraxial region 110 and concave at a peripheral region;

the image-side surface S2 of the first lens element L1 is convex at a paraxial region 110 and concave at a peripheral region;

the object-side surface S3 of the second lens element L2 is convex at a paraxial region 110 and convex at a peripheral region;

the image-side surface S4 of the second lens element L2 is concave at a paraxial region 110 and convex at a peripheral region;

the object-side surface S5 of the third lens element L3 is convex at a paraxial region 110 and concave at a peripheral region;

the image-side surface S6 of the third lens element L3 is concave at a paraxial region 110 and convex at a peripheral region;

the object-side surface S7 of the fourth lens element L4 is concave at a paraxial region 110 and convex at a peripheral region;

the image-side surface S8 of the fourth lens element L4 is convex at the paraxial region 110 and concave at the peripheral region;

the object-side surface S9 of the fifth lens element L5 is convex at a paraxial region 110 and convex at a peripheral region;

the image-side surface S10 of the fifth lens element L5 is concave at the paraxial region 110 and concave at the periphery.

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

It should be noted that, in the present application, when a surface of the lens is described as being convex at a position near the optical axis 110 (the central region of the surface), it is understood that the region of the surface of the lens near the optical axis 110 is convex. When a surface of the lens is described as concave at the circumference, it is understood that the surface is concave in the region near the maximum effective aperture. For example, when the surface is convex at the paraxial region 110 and also convex at the peripheral region, the shape of the surface from the center (the intersection of the surface with the optical axis 110) to the peripheral direction may be purely convex; or the convex shape at the center is firstly transited to the concave shape, and then the convex shape is changed to the convex shape near the position of the maximum effective aperture. Here, only examples are made to illustrate the relationship at the optical axis 110 and the circumference, and various shape structures (concave-convex relationship) of the surface are not fully embodied, but other cases can be derived from the above examples.

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

Further, the optical system 100 satisfies the conditional expression: f/tan (fov) =11.165 mm; where f is the effective focal length of the optical system 100 and the FOV is the field angle of the optical system 100. When the above conditional expressions are satisfied, the ratio between the effective focal length of the optical system 100 and the tangent value of the field angle can be reasonably configured, which is beneficial to having a larger field angle under the requirement of maintaining a long-focus system, and improving the utilization rate of the light rays of the optical system 100 and the light rays, thereby being beneficial to improving the imaging quality.

The optical system 100 satisfies the conditional expression: CT3/sag31= 1.343; CT3 is the thickness of the third lens element L3 on the optical axis 110, i.e., the center thickness of the third lens element L3, and sag31 is the distance from the maximum effective aperture of the object-side surface S5 of the third lens element L3 to the intersection point of the object-side surface S5 of the third lens element L3 and the optical axis 110 in the direction of the optical axis 110, i.e., the rise of the object-side surface S5 of the third lens element L3 at the maximum effective aperture. When the above conditional expressions are satisfied, the ratio of the center thickness to the rise of the object-side surface S5 of the third lens L3 can be reasonably controlled, which is beneficial to reasonably configuring the shape of the third lens L3, thereby being beneficial to providing good conditions for processing and assembling the third lens L3 and improving the imaging quality of the optical system 100; meanwhile, the third lens L3 is favorable for correcting the curvature of field generated by the object-side lens (i.e., the first lens L1 and the second lens L2), so as to balance the curvature of field of the optical system 100, thereby being favorable for improving the imaging quality of the optical system 100.

The optical system 100 satisfies the conditional expression: f/f1+ f/| f2| = 3.209; wherein f1 is the effective focal length of the first lens L1, and f2 is the effective focal length of the second lens L2. When the above conditional expressions are satisfied, the sum of the ratios of the effective focal length of the optical system 100 to the effective focal lengths of the first lens L1 and the second lens L2 can be reasonably distributed, so that the refractive powers of the first lens L1 and the second lens L2 in the system are reasonably configured, and therefore, the excessive degree of surface-type bending of the first lens L1 and the second lens L2 is favorably avoided, and further, the processing and the assembly of the first lens L1 and the second lens L2 are favorably realized, the serious aberration generated when the first lens L1 and the second lens L2 converge light rays is favorably avoided, and the imaging quality of the optical system 100 is favorably improved; meanwhile, the contribution of the refractive power of the first lens element L1 and the second lens element L2 in the system is controlled, and the deflection angles of the marginal field rays passing through the first lens element L1 and the second lens element L2 are also controlled, so that the field rays are effectively converged, the illumination of the imaging surface S13 is improved, the phenomena of dark corners and the like are avoided, and the system stability is improved.

The optical system 100 satisfies the conditional expression: sd11/sd31= 1.263; here, sd11 is half of the maximum effective aperture of the object-side surface S1 of the first lens L1, and sd31 is half of the maximum effective aperture of the object-side surface S5 of the third lens L3. When satisfying above-mentioned conditional expression, can the half ratio of the half of the maximum effective bore of rational distribution first lens L1 and the half of the maximum effective bore of third lens L3, it is too big to avoid the difference of the maximum effective bore of first lens L1 and third lens L3, be convenient for optical system 100's equipment and promote the yield, be favorable to restricting the scope through the incident light of first lens L1 and third lens L3 simultaneously, keep the high image light of middle quality, reject the relatively poor stray light of marginal quality, thereby reduce optical system 100's off-axis aberration, and then promote optical system 100's imaging quality.

The optical system 100 satisfies the conditional expression: TTL/ImgH = 3.312; wherein, TTL is a distance from the object-side surface S1 of the first lens element L1 to the image plane S13 of the optical system 100 on the optical axis 110, i.e., the total optical length of the optical system 100, and ImgH is half of the image height corresponding to the maximum field angle of the optical system 100. When the above conditional expressions are satisfied, the ratio of the total optical length of the optical system 100 to the half-image height can be reasonably distributed, so that the total optical length of the optical system 100 can be shortened, the miniaturization design is realized, the size of the imaging surface S13 of the optical system 100 can be improved, and the imaging quality of the optical system 100 can be improved.

The optical system 100 satisfies the conditional expression: sag52/sag51= 1.033; here, sag51 is a distance from the maximum effective aperture of the object-side surface S9 of the fifth lens L5 to the intersection point of the object-side surface S9 of the fifth lens L5 and the optical axis 110 in the direction of the optical axis 110, that is, a rise of the object-side surface S9 of the fifth lens L5 at the maximum effective aperture, and sag52 is a rise of the maximum effective aperture of the image-side surface S10 of the fifth lens L5 to the intersection point of the image-side surface S10 of the fifth lens L5 and the optical axis 110, that is, a rise of the image-side surface of the fifth lens L5 at the maximum effective aperture. When the conditional expressions are satisfied, the bending degree of the surface type of the object side surface S9 and the image side surface S10 of the fifth lens L5 can be constrained, which is beneficial to avoiding the difficulty in processing caused by too complicated surface type, and simultaneously, is beneficial to ensuring that the chief ray is incident to the imaging surface S13 at a smaller incident angle, thereby being beneficial to improving the imaging quality of the system.

The optical system 100 satisfies the conditional expression: (CT2+ CT3+ CT4)/(CT23+ CT34) = 2.820; wherein, CT2 is the thickness of the second lens element L2 on the optical axis 110, CT3 is the thickness of the third lens element L3 on the optical axis 110, CT4 is the thickness of the fourth lens element L4 on the optical axis 110, CT23 is the distance from the image-side surface of the second lens element L2 to the object-side surface of the third lens element L3 on the optical axis 110, and CT34 is the distance from the image-side surface of the third lens element L3 to the object-side surface of the fourth lens element L4 on the optical axis 110. When the above conditional expressions are satisfied, the central thicknesses of the second lens L2, the third lens L3 and the fourth lens L4 and the air intervals among the central thicknesses can be reasonably distributed, so that sufficient space deflection light rays are provided among the second lens L2, the third lens L3 and the fourth lens L4, the reduction of the deflection angle of the light rays in the refraction of the second lens L2 to the fourth lens L4 is facilitated, in addition, sufficient design and arrangement space is provided among the second lens L2 to the fourth lens L4, the reduction of tolerance sensitivity in lens assembly is facilitated, ghost images are prevented, and the miniaturization of the optical system 100 is facilitated.

The optical system 100 satisfies the conditional expression: BFL/(CT4+ CT5) = 3.657; BFL is the shortest distance from the image-side surface S10 of the fifth lens element L5 to the image-forming surface S13 of the optical system 100 in the direction of the optical axis 110, CT4 is the thickness of the fourth lens element L4 on the optical axis 110, i.e. the central thickness of the fourth lens element L4, and CT5 is the thickness of the fifth lens element L5 on the optical axis 110, i.e. the central thickness of the fifth lens element L5. When the above conditional expressions are satisfied, the ratio of the back focus of the optical system 100 to the sum of the thicknesses of the fourth lens L4 and the fifth lens L5 can be reasonably configured, which is favorable for leaving enough fitting space for assembling the optical system 100 and the photosensitive element, the sum of the central thickness of the fourth lens L4 and the central thickness of the fifth lens L5 is limited, which is favorable for compensating the distortion generated by the object side lenses (i.e., the first lens L1 to the third lens L3) of the fourth lens L4, and is favorable for manufacturing and molding the fourth lens L4 and the fifth lens L5.

The optical system 100 satisfies the conditional expression: f/EPD = 1.564; where EPD is the entrance pupil diameter of the optical system 100. When the above conditional expressions are satisfied, the effective focal length of the optical system 100 and the ratio of the effective focal length to the same diameter can be reasonably configured, so that the optical system 100 has a large aperture, the size of the airy disk of the optical system 100 is reduced, the imaging quality of the optical system 100 is improved, meanwhile, the light entering the diameter of the entrance pupil is sufficient, the dark angle of the imaging surface is avoided, and the shooting effect of the optical system 100 in a weak light environment is improved.

In addition, the parameters of the optical system 100 are given in table 1. Here, the imaging surface S13 in table 1 may be understood as an imaging surface of the optical system 100. The elements from the object plane (not shown) to the image plane S13 are arranged in the order of the elements from top to bottom in table 1. The Y radius in table 1 is the radius of curvature of the object-side or image-side surface at the optical axis 110 for the corresponding surface number. Surface numbers S1 and S2 denote an object-side surface S1 and an image-side surface S2 of the first lens L1, respectively, that is, in the same lens, a surface with a smaller surface number is an object-side surface, and a surface with a larger surface number is an image-side surface. The first numerical value in the "thickness" parameter column of the first lens element L1 is the thickness of the lens element along the optical axis 110, and the second numerical value is the distance between the image-side surface and the rear surface of the lens element along the image-side direction along the optical axis 110.

It should be noted that in this embodiment and the following embodiments, the optical system 100 may not be provided with the infrared filter L6, but the distance from the image side surface S10 of the fifth lens L5 to the image plane S13 is kept unchanged.

In the first embodiment, the effective focal length f =9.057mm, the total optical length TTL =10.830mm, the maximum field angle FOV =39deg, and the f-number FNO =1.565 of the optical system 100. The optical system 100 can obtain enough light when shooting distant objects, thereby realizing long-focus, miniaturized and high-quality imaging effect.

The reference wavelength of the focal length of each lens is 555nm, the reference wavelengths of the refractive index and the Abbe number of each lens are 587.56nm, and the same is also realized in other embodiments.

TABLE 1

Further, aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are given by table 2. The surface numbers S1-S10 represent the image side or the object side S1-S10, respectively. And K-a20 from top to bottom respectively represent the types of aspheric coefficients, where K represents a conic coefficient, a4 represents a quartic aspheric coefficient, a6 represents a sixth-order aspheric coefficient, A8 represents an eighth-order aspheric coefficient, and so on. In addition, the aspherical surface coefficient formula is as follows:

wherein Z is the distance from the corresponding point on the aspheric surface to the plane tangent to the surface vertex, r is the distance from the corresponding point on the aspheric surface to the optical axis 110, c is the curvature of the aspheric surface vertex, K is the conic coefficient, and Ai is the coefficient corresponding to the i-th high-order term in the aspheric surface type formula.

TABLE 2

Fig. 2 includes a Longitudinal Spherical Aberration diagram (Longitudinal Spherical Aberration) of the optical system 100, in which the Longitudinal Spherical Aberration curve represents the deviation of the converging focus of the light rays with different wavelengths after passing through the lens, the ordinate represents the Normalized Pupil coordinate (Normalized Pupil coordiator) from the Pupil center to the Pupil edge, and the abscissa represents the focus deviation, i.e., the distance (in mm) from the image plane to the intersection of the light rays and the optical axis 110. It can be known from the longitudinal spherical aberration diagram that the convergent focus deviation degrees of the light rays with different wavelengths in the first embodiment tend to be consistent, and the diffuse speckles or color halos in the imaging picture are effectively inhibited. Fig. 2 also includes an astigmatism graph (ASTIGMATIC FIELD CURVES) of the optical system 100, in which the abscissa represents the focus offset and the ordinate represents the image height in mm, and the S-curve and the T-curve in the astigmatism graph represent sagittal curvature at 555nm and meridional curvature at 555nm, respectively. As can be seen from the figure, the curvature of field of the optical system 100 is small, the curvature of field and astigmatism of each field are well corrected, and the center and the edge of the field have clear images. Fig. 2 also includes a distortion plot (direction) of the optical system 100, the distortion plot representing distortion magnitude values for different angles of view, where the abscissa represents distortion values in units, and the ordinate represents image height in units of mm. As can be seen from the figure, the image distortion caused by the main beam is small, and the imaging quality of the system is excellent.

Second embodiment

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

In the second embodiment, the surface shape of each lens is substantially the same as that of each lens in the first embodiment, and the same points are not described again, but the differences are as follows: the image-side surface S4 of the second lens L2 is concave at the circumference; the object-side surface S5 of the third lens element L3 is convex at the circumference; the object-side surface S7 of the fourth lens element L4 is convex at a paraxial region 110 and concave at a peripheral region; the image-side surface S8 of the fourth lens element L4 is concave at the paraxial region 110.

The object-side surface and the image-side surface of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are aspheric. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4 and the fifth lens L5 are all made of plastic. In addition, the parameters of the optical system 100 are given in table 3, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

TABLE 3

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

TABLE 4

According to the provided parameter information, the following data can be deduced:

TABLE 5

In addition, as can be seen from fig. 4, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are well controlled, so that the optical system 100 of this embodiment has good imaging quality.

Third embodiment

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

In the third embodiment, the surface shape of each lens is substantially the same as that of each lens in the first embodiment, and the same points are not described again, but the differences are as follows: the image-side surface S4 of the second lens L2 is concave at the circumference; the object-side surface S5 of the third lens L3 is convex at the circumference; the image-side surface S10 of the fifth lens element L5 is convex at the circumference.

The object-side surface and the image-side surface of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4 and the fifth lens L5 are aspheric. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4 and the fifth lens L5 are all made of plastic. In addition, the parameters of the optical system 100 are given in table 6, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein again.

TABLE 6

Further, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are shown in table 7, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

TABLE 7

TABLE 8

In addition, as can be seen from fig. 6, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are well controlled, so that the optical system 100 of this embodiment has good imaging quality.

Fourth embodiment

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

In the fourth embodiment, the surface shape of each lens is substantially the same as that of each lens in the first embodiment, and the same points are not described again, but the differences are as follows: the image-side surface S4 of the second lens L2 is concave at the circumference; the object-side surface S5 of the third lens L3 is convex at the circumference; the image-side surface S6 of the third lens L3 is concave at the circumference; the object-side surface S7 of the fourth lens element L4 is convex at the paraxial region 110.

The object-side surface and the image-side surface of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are aspheric. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4 and the fifth lens L5 are all made of plastic. In addition, the parameters of the optical system 100 are given in table 9, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

TABLE 9

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

Watch 10

TABLE 11

In addition, as can be seen from fig. 8, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are well controlled, so that the optical system 100 of this embodiment has good imaging quality.

Fifth embodiment

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

In the fifth embodiment, the surface shape of each lens is substantially the same as that of each lens in the first embodiment, and the same points are not described again, but the differences are as follows: the image-side surface S2 of the first lens element L1 is concave at the paraxial region 110; the object-side surface S3 of the second lens element L2 is concave at the paraxial region 110; the image-side surface S4 of the second lens L2 is concave at the circumference; the object-side surface S5 of the third lens L3 is convex at the circumference; the image-side surface S6 of the third lens L3 is concave at the circumference; the object side S9 of the fifth lens L5 is concave at the circumference.

The object-side surface and the image-side surface of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are aspheric. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4 and the fifth lens L5 are all made of plastic. In addition, the parameters of the optical system 100 are given in table 12, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

TABLE 12

Further, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are shown in table 13, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

Watch 13

TABLE 14

In addition, as can be seen from fig. 10, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are well controlled, so that the optical system 100 of this embodiment has good imaging quality.

Sixth embodiment

Referring to fig. 11 and 12, fig. 11 is a schematic structural diagram of the optical system 100 in the sixth embodiment, and the optical system 100 includes, in order from an object side to an image side, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with positive refractive power, and a fifth lens element L5 with negative refractive power. Fig. 12 is a graph showing longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the sixth embodiment, in order from left to right.

In the sixth embodiment, the surface shape of each lens is substantially the same as that of each lens in the first embodiment, and the same points are not described again, but the differences are as follows: the image-side surface S2 of the first lens element L1 is concave at the paraxial region 110; the object-side surface S3 of the second lens element L2 is concave at the paraxial region 110;

the image-side surface S4 of the second lens L2 is concave at the circumference; the object-side surface S5 of the third lens L3 is convex at the circumference; the image-side surface S6 of the third lens L3 is concave at the circumference; the object side S9 of the fifth lens L5 is concave at the circumference.

The object-side surface and the image-side surface of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are aspheric. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4 and the fifth lens L5 are all made of plastic. In addition, the parameters of the optical system 100 are given in table 15, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

Watch 15

Further, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are shown in table 16, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

TABLE 16

TABLE 17

In addition, as can be seen from fig. 12, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are well controlled, so that the optical system 100 of this embodiment has good imaging quality.

Seventh embodiment

Referring to fig. 13 and 14, fig. 13 is a schematic structural diagram of the optical system 100 in the seventh embodiment, and the optical system 100 includes, in order from an object side to an image side, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with negative refractive power, and a fifth lens element L5 with negative refractive power. Fig. 14 is a graph showing the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the seventh embodiment from left to right.

In the seventh embodiment, the surface shape of each lens is substantially the same as that of each lens in the first embodiment, and the description is omitted here for the same points, but the differences are as follows: the image-side surface S2 of the first lens element L1 is concave at the paraxial region 110; the object-side surface S5 of the third lens L3 is convex at the circumference; the image-side surface S6 of the third lens L3 is concave at the circumference; the object-side surface S9 of the fifth lens L5 is concave at the circumference; the image-side surface S10 of the fifth lens element L5 is convex at the circumference.

The object-side surface and the image-side surface of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are aspheric. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4 and the fifth lens L5 are all made of plastic. In addition, the parameters of the optical system 100 are given in table 18, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

Watch 18

Further, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are shown in table 19, and the definitions of the parameters can be derived from the first embodiment, which is not repeated herein.

Watch 19

watch 20

In addition, as can be seen from fig. 14, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are well controlled, so that the optical system 100 of this embodiment has good imaging quality.

Eighth embodiment

Referring to fig. 15 and 16, fig. 15 is a schematic structural diagram of the optical system 100 in the eighth embodiment, and the optical system 100 includes, in order from an object side to an image side, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with negative refractive power, and a fifth lens element L5 with negative refractive power. Fig. 16 is a graph showing the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the eighth embodiment from left to right.

In the eighth embodiment, the surface shape of each lens is substantially the same as that of each lens in the first embodiment, and the same points are not described again, but the differences are as follows: the object-side surface S1 of the first lens L1 is convex at the circumference; the image-side surface S2 of the first lens element L1 is concave at the paraxial region 110; the image-side surface S4 of the second lens L2 is concave at the circumference; the object-side surface S5 of the third lens L3 is convex at the circumference; the image-side surface S6 of the third lens L3 is concave at the circumference; the object-side surface S9 of the fifth lens element L5 is concave at a paraxial region 110 and concave at a peripheral region; the image-side surface S10 of the fifth lens element L5 is convex at a paraxial region 110 and convex at a peripheral region.

The object-side surface and the image-side surface of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are aspheric. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4 and the fifth lens L5 are all made of plastic. In addition, the parameters of the optical system 100 are given in table 21, and the definitions of the parameters can be derived from the first embodiment, which is not repeated herein.

TABLE 21

Further, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are given in table 22, and the definitions of the parameters can be derived from the first embodiment, which is not repeated herein.

TABLE 22

TABLE 23

In addition, as can be seen from fig. 16, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are well controlled, so that the optical system 100 of this embodiment has good imaging quality.

Referring to fig. 18, in some embodiments, the optical system 100 can be assembled with the photosensitive element 210 to form the lens module 200. At this time, the light-sensing surface of the light-sensing element 210 can be regarded as the image-forming surface S13 of the optical system 100. The lens module 200 may further include an infrared filter L6, and the infrared filter L6 is disposed between the image side surface S10 and the image plane S13 of the fifth lens element L5. Specifically, the photosensitive element 210 may be a Charge Coupled Device (CCD) or a Complementary Metal-Oxide SemiconduCTor (CMOS) Device. The lens module 200 using the optical system 100 can obtain enough light even when shooting distant objects, thereby achieving a long focal length, a small size, and a high quality imaging effect.

Referring to fig. 18 and 19, in some embodiments, the lens module 200 can be applied to an electronic device 300, the electronic device includes a housing 310, and the lens module 200 is disposed on the housing 310. Specifically, the electronic apparatus 300 may be, but is not limited to, a wearable device such as a mobile phone, a video phone, a smart phone, an electronic book reader, a vehicle-mounted image capturing apparatus such as a car recorder, or a smart watch. When the electronic device 300 is a smartphone, the housing 310 may be a middle frame of the electronic device 300. The lens module 200 is used in the electronic device 300 to obtain enough light when shooting distant objects, thereby realizing long-focus, miniaturized, and high-quality imaging effect.

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

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that various changes and modifications can be made by those skilled in the art without departing from the spirit of the invention, and these changes and modifications are all within the scope of the invention. Therefore, the protection scope of the present patent should be subject to the appended claims.

Claims

1. An optical system, wherein five lenses having refractive power are provided, and the optical system sequentially includes, from an object side to an image side along an optical axis:

a fourth lens element with refractive power;

a fifth lens element with refractive power;

and the optical system satisfies the following conditional expression:

11mm≤f/tan(FOV)≤13mm；

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

0.85≤CT3/sag31≤1.5；

wherein CT3 is a thickness of the third lens element along the optical axis, and sag31 is a distance from a maximum effective aperture of an object-side surface of the third lens element to an intersection point of the object-side surface of the third lens element and the optical axis along the optical axis.

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

2.7≤f/f1+f/|f2|≤3.4；

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

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

1.2≤sd11/sd31≤1.6；

wherein sd11 is half of the maximum effective aperture of the object-side surface of the first lens, and sd31 is half of the maximum effective aperture of the object-side surface of the third lens.

5. The optical system according to claim 1, wherein the optical system satisfies the following conditional expression:

3.2≤TTL/ImgH≤3.4；

wherein, TTL is a distance on an optical axis from an object-side surface of the first lens element to an image plane of the optical system, and ImgH is half of an image height corresponding to a maximum field angle of the optical system.

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

0.7≤sag52/sag51≤1.2；

wherein sag51 is a distance in the optical axis direction from the maximum effective aperture of the object-side surface of the fifth lens element to the intersection point of the object-side surface of the fifth lens element and the optical axis, and sag52 is a distance in the optical axis direction from the maximum effective aperture of the image-side surface of the fifth lens element to the intersection point of the image-side surface of the fifth lens element and the optical axis.

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

1.5 is less than or equal to (CT2+ CT3+ CT4)/(CT23+ CT34) is less than or equal to 2.9; and/or the presence of a gas in the gas,

2.2≤BFL/(CT4+CT5)≤4.1；

wherein, CT2 is the thickness of the second lens element on the optical axis, CT3 is the thickness of the third lens element on the optical axis, CT4 is the thickness of the fourth lens element on the optical axis, CT5 is the thickness of the fifth lens element on the optical axis, CT23 is the distance from the image-side surface of the second lens element to the object-side surface of the third lens element on the optical axis, CT34 is the distance from the image-side surface of the third lens element to the object-side surface of the fourth lens element on the optical axis, and BFL is the shortest distance from the image-side surface of the fifth lens element to the imaging surface of the optical system in the optical axis direction.

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

1.5≤f/EPD≤1.7；

wherein EPD is an entrance pupil diameter of the optical system; and/or the presence of a gas in the gas,

the optical system further comprises a steering prism, and the steering prism is arranged between an object plane of the optical system and an object side surface of the first lens.

9. A lens module comprising a photosensitive element and the optical system as claimed in any one of claims 1 to 8, wherein the photosensitive element is disposed on the image side of the optical system.

10. An electronic device comprising a housing and the lens module as claimed in claim 9, wherein the lens module is disposed on the housing.