CN218471035U

CN218471035U - Optical system, image capturing module and electronic equipment

Info

Publication number: CN218471035U
Application number: CN202121456870.1U
Authority: CN
Inventors: 刘彬彬; 邹海荣; 李明
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2021-06-29
Filing date: 2021-06-29
Publication date: 2023-02-10
Anticipated expiration: 2031-06-29

Abstract

The utility model relates to an optical system, get for instance module and electronic equipment. The optical system includes, in order from an object side to an image side along an optical axis: a first lens element with positive refractive power having a convex object-side surface and a concave image-side surface; a second lens element with refractive power having a convex object-side surface at paraxial region; a third lens element with refractive power; a fourth lens element with refractive power having a convex object-side surface at paraxial region and a concave image-side surface at optical axis; a fifth lens element with refractive power having a concave object-side surface at paraxial region; a sixth lens element with positive refractive power having a convex object-side surface at paraxial region; a seventh lens element with negative refractive power having a concave image-side surface at paraxial region; and satisfies the following conditions: the | f (12)/f (67) | is less than or equal to 0.5; f (12) is a combined focal length of the first lens and the second lens, and f (67) is a combined focal length of the sixth lens and the seventh lens. The optical system can meet the requirement of miniaturization design.

Description

Optical system, image capturing module and electronic equipment

Technical Field

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

Background

With the rapid development of electronic devices such as smart phones and tablet computers, more and more electronic devices are equipped with an image capturing module to realize a camera shooting function. The image capturing module comprises an optical system and a photosensitive element, and the optical system is used for receiving and adjusting light rays so as to enable the light rays to form images on the photosensitive element. The optical system occupies a certain space in the electronic device, affecting the volume of the electronic device. Meanwhile, people have higher and higher requirements on electronic equipment, and the electronic equipment is required to have a good camera shooting function and is expected to be miniaturized, so that the size of the electronic equipment is reduced, and the electronic equipment is convenient to carry and use. However, the size of the optical system is yet to be reduced, otherwise it is difficult to meet the requirement of miniaturization design of electronic equipment when the optical system is applied to the electronic equipment.

SUMMERY OF THE UTILITY MODEL

Accordingly, it is desirable to provide an optical system, an image capturing module and an electronic device, which are directed to the problem that the conventional optical system is difficult to satisfy the requirement of miniaturization design of the electronic device.

An 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 and a concave image-side surface;

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

a third lens element with refractive power;

a fourth lens element with refractive power having a convex object-side surface at a paraxial region and a concave image-side surface at an optical axis;

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

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

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

and the optical system satisfies the following conditional expression:

|f12/f67|≤0.5；

wherein f12 is a combined focal length of the first lens and the second lens, and f67 is a combined focal length of the sixth lens and the seventh lens.

In the optical system, the positive refractive power of the first lens element, the shape of the surface with the convex object-side surface and the concave image-side surface are favorable for incident light rays with a large angle with the optical axis to enter the optical system and to be effectively converged, so that the total length of the optical system is favorably shortened, and the miniaturization design is realized. The second lens element and the third lens element have refractive power, and the second lens element and the third lens element are matched with the convex surface of the object-side surface of the second lens element, so that the light rays converged by the first lens element can be smoothly transmitted to the rear lens element, and the aberration of the object-side lens element can be primarily corrected, thereby preventing a large amount of aberration which is difficult to correct from being generated and increasing the correction load of the rear lens element. The surface type that the object side surface of the fourth lens is convex and the image side surface is concave can be matched with the object side lens to further converge incident light so as to shorten the total length of the optical system. The refractive power and the object-side surface shape of the fifth lens element can further balance the aberration which is difficult to correct and is caused by the lens elements on the object side when converging the incident light. The positive refractive power of the sixth lens element and the convex surface of the object-side surface are favorable for counteracting the aberration generated by the object-side lens element. The seventh lens element with negative refractive power has positive refractive power, and the positive and negative refractive power can cancel out aberration generated by each other. The corresponding surface shapes of the second lens, the third lens, the fourth lens and the fifth lens are mutually matched, so that light can be smoothly transited among the lenses, and the optical surface in the lens is prevented from excessively deflecting the light.

When the condition is further satisfied under the conditions of having the refractive power and the surface type design, the ratio of the combined focal length of the first lens and the second lens and the combined focal length of the sixth lens and the seventh lens can be reasonably set, so that the first lens and the second lens can collect light rays in a larger angle range, the sixth lens and the seventh lens can effectively converge the light rays at the center and at the edge of a nearby field of view, the structure of the optical system is more compact, the total length of the optical system can be shortened, and the requirement of miniaturization design of electronic equipment can be satisfied; in addition, the sixth lens and the seventh lens can effectively correct aberration generated by the first lens and the second lens integrally, so that the imaging quality of the optical system is improved.

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

|(R51-R52)/(R51+R52)|≤100；

wherein R51 is a curvature radius of an object-side surface of the fifth lens element at an optical axis, and R52 is a curvature radius of an image-side surface of the fifth lens element at the optical axis. When the condition formula is satisfied, the object side surface and the image side surface of the fifth lens can be reasonably configured, so that the surface shape of the fifth lens cannot be too gentle or excessively bent, the aberration of the optical system can be corrected by the fifth lens, and the imaging quality of the optical system can be improved. Exceeding the conditional expression scope, the face type of the fifth lens will be too gentle, will result in the light degree of deflection undersize, be unfavorable for optical system's aberration correction, perhaps the fifth lens face type will be too crooked and lead to lens shaping degree of difficulty increase, increase optical system's manufacturing cost.

|(R21-R22)/(R21+R22)|≤30；

wherein R21 is a curvature radius of an object-side surface of the second lens element at the optical axis, and R22 is a curvature radius of an image-side surface of the second lens element at the optical axis. When the condition formula is satisfied, the object side surface and the image side surface of the second lens can be reasonably configured, so that the surface shape of the second lens cannot be too gentle or excessively bent, the aberration of the optical system can be corrected by the second lens, and the imaging quality of the optical system can be improved. Exceeding the conditional expression scope, the face type of second lens will be too gentle, will lead to light deflection degree undersize, is unfavorable for optical system's aberration to correct, perhaps the second lens face type will be too crooked leads to lens shaping degree of difficulty to increase, increases optical system's manufacturing cost.

|f/f2+f/f4|≤1.5；

wherein f is an effective focal length of the optical system, f2 is an effective focal length of the second lens, and f4 is an effective focal length of the fourth lens. When the conditional expressions are met, the refractive powers of the second lens and the fourth lens in the optical system can be reasonably configured, so that the spherical aberration generated by the first lens and the second lens integrally can be balanced, the integral resolving power of the optical system can be improved, and the aberration of the marginal field of view of the optical system can be corrected; in addition, the second lens element and the fourth lens element are used as intermediate lens elements, and a reasonable refractive power distribution can provide a sufficient beam transfer space for the object-side lens element and the image-side lens element of the optical system, thereby facilitating shortening of the total system length of the optical system and achieving a compact design. The relation is satisfied promptly, can promote optical system's resolving power for optical system can also possess good image quality when carrying out miniaturized design.

15≤|f2/SAG22|≤135；

where f2 is the effective focal length of the second lens, and SAG22 is the rise of the image-side surface of the second lens at the maximum effective aperture, that is, the distance from the intersection point of the image-side surface of the second lens and the optical axis to the maximum effective aperture of the image-side surface of the second lens in the optical axis direction. When the conditional expressions are satisfied, the refractive power of the second lens element and the image side surface shape of the second lens element can be reasonably configured, which is beneficial to correcting chromatic aberration and spherical aberration of the optical system, thereby improving the imaging quality of the optical system; meanwhile, the surface shape of the second lens is not too gentle, and the improvement of the capacity of the optical system for converging light rays is facilitated, so that the total length of the optical system is shortened, and the miniaturization design is realized.

50≤|f5/SAG52|≤740；

where f5 is an effective focal length of the fifth lens, and SAG52 is a sagittal height of the image side surface of the fifth lens at the maximum effective aperture, that is, a distance from an intersection of the image side surface of the fifth lens and the optical axis to the maximum effective aperture of the image side surface of the fifth lens in the optical axis direction. When the conditional expressions are satisfied, the refractive power of the fifth lens element and the image side surface shape of the fifth lens element can be reasonably configured, which is beneficial to correcting chromatic aberration and spherical aberration of the optical system, thereby improving the imaging quality of the optical system; meanwhile, the surface shape of the fifth lens is not too gentle, and the capability of converging light rays of the optical system is favorably improved, so that the total length of the system of the optical system is favorably shortened, and the miniaturized design is realized.

|SAG22/SAG52|≤2；

wherein SAG22 is the saggital height of the image side of the second lens at the maximum effective aperture and SAG52 is the saggital height of the image side of the fifth lens at the maximum effective aperture. When the conditional expression is met, the ratio of the rise of the second lens to the rise of the fifth lens can be reasonably configured, so that the spherical aberration of the optical system is balanced, and the integral resolving power of the optical system is improved; meanwhile, the reasonable design of the surface types of the second lens and the fifth lens is beneficial to the sixth lens and the seventh lens on the image side to effectively correct the aberration of the marginal field generated by the first lens and the second lens on the object side; in addition, the surface shapes of the second lens and the fifth lens are not excessively bent, and enough space is provided for arrangement among the lenses, so that the total length of the optical system is favorably shortened, and the miniaturization design is realized. Namely, the relation is satisfied, and the optical system has good imaging quality while being miniaturized.

In one embodiment, an inflection point exists on at least one of the object-side surface and the image-side surface of the seventh lens, and the optical system satisfies the following conditional expression:

1≤(|SAG71|+|SAG72|)/CT7≤2；

SAG71 is the rise of the object side surface of the seventh lens at the maximum effective aperture, namely the distance from the intersection point of the object side surface of the seventh lens and the optical axis to the maximum effective aperture of the object side surface of the seventh lens in the optical axis direction, SAG72 is the rise of the image side surface of the seventh lens at the maximum effective aperture, namely the distance from the intersection point of the image side surface of the seventh lens and the optical axis to the maximum effective aperture of the image side surface of the seventh lens in the optical axis direction, and CT7 is the thickness of the seventh lens in the optical axis direction. The seventh lens is provided with an inflection point which is used as a lens closest to an imaging surface of the optical system, so that the deflection force of a light beam reaching the imaging surface of the optical system can be more uniform, and the distortion and the field curvature generated by each lens on the object side of the seventh lens can be corrected; when the condition formula is met, the thickness and the surface shape of the seventh lens can be reasonably configured, so that the seventh lens cannot be too thin or too thick, and the surface shape of the seventh lens cannot be too gentle or too curved, thereby being beneficial to reducing the incident angle of light rays on an image surface and reducing the sensitivity of an optical system. If the upper limit of the conditional expression is exceeded, the edge of the seventh lens is too thick, which tends to increase field curvature aberration and cause field curvature. When the edge of the seventh lens is too thin, effective deflection and convergence of light in the edge field of view cannot be realized, so that the incident angle of the light at the edge of the image plane is difficult to reduce, and the dark angle phenomenon is increased.

An image capturing module includes a photosensitive element and the optical system of any of the above embodiments, wherein the photosensitive element is disposed at an image side of the optical system. The optical system is adopted in the image capturing module, the optical system is compact in structure, and the requirement of miniaturization design of the image capturing module can be met.

An electronic device comprises a shell and the image capturing module, wherein the image capturing module is arranged on the shell. Adopt above-mentioned getting for instance module among the electronic equipment, optical system's compact structure can satisfy the demand of electronic equipment miniaturized design.

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 in a first embodiment of the present application;

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

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

FIG. 5 is a schematic 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 in 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 in 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 in a fifth embodiment of the present application;

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

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

Detailed Description

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

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

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

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

In the present application, unless expressly stated or limited otherwise, a first feature "on" or "under" a second feature may be directly contacting the second feature or the first and second features may be indirectly contacting the second feature through intervening media. 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, an optical system 100 includes, in order from an object side to an image side along an optical axis 110, a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, a fifth lens element L5, a sixth lens element L6, and a seventh lens element L7. 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, the fifth lens element L5 includes an object-side surface S9 and an image-side surface S10, the sixth lens element L6 includes an object-side surface S11 and an image-side surface S12, and the seventh lens element L7 includes an object-side surface S13 and an image-side surface S14. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are 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 at a paraxial region 110 and a concave image-side surface S2 at the paraxial region 110. The second lens element L2, the third lens element L3 and the fourth lens element L4 all have refractive power. The object-side surface S3 of the second lens element L2 is convex at the paraxial region 110. The object-side surface S7 of the fourth lens element L4 is convex at the paraxial region 110, and the image-side surface S8 is concave at the paraxial region 110. The fifth lens element L5 with refractive power has a concave object-side surface S9 at a paraxial region 110. The sixth lens element L6 with positive refractive power has a convex object-side surface S11 at a paraxial region 110. The seventh lens element L7 has negative refractive power. The image side surface S14 is concave at the paraxial region 110.

The positive refractive power of the first lens element L1, the object-side surface S1 being a convex surface, and the image-side surface S2 being a concave surface, are favorable for the incident light beams forming a large angle with the optical axis 110 to enter the optical system 100 and to be effectively converged, thereby being favorable for shortening the total length of the optical system 100 and realizing a miniaturized design. The second lens element L2 and the third lens element L3 have refractive power, and the convex surface shape of the object-side surface S3 of the second lens element L2 is matched to facilitate smooth transmission of the light converged by the first lens element L1 to the rear lens element, and to primarily correct the aberration of the object-side lens element, so as to avoid generating a large amount of aberration which is difficult to correct, and increase the correction burden of the rear lens element. The surface type of the fourth lens element L4 with the convex object-side surface S7 and the concave image-side surface S8 can further converge the incident light to shorten the total length of the optical system 100. The refractive power and the object-side surface S9 profile of the fifth lens element L5 can further balance the difficult-to-correct aberrations caused by the object-side lenses when converging incident light. The positive refractive power of the sixth lens element L6 and the convex shape of the object-side surface S11 are favorable for counteracting the aberration generated by the object-side lens element. The seventh lens element L7 provides negative refractive power, which is matched with the positive refractive power of the sixth lens element L6, so that the positive and negative refractive power lens elements can mutually cancel out the aberration generated by each other, and the convex surface of the object-side surface S11 of the sixth lens element L6 is matched with the concave surface of the image-side surface S14 of the seventh lens element L7, thereby facilitating to correct the off-axis coma and astigmatism of the optical system 100. The corresponding surface shapes of the second lens L2, the third lens L3, the fourth lens L4 and the fifth lens L5 are mutually matched, so that light rays can be smoothly transited among the lenses, and the optical surface is prevented from excessively deflecting the light rays.

In addition, in some embodiments, the optical system 100 is provided with a stop STO, which may be disposed on the object side of the first lens L1, or on the object side surface S1 of the first lens L1. In some embodiments, the optical system 100 further includes an infrared filter L8 disposed on the image side of the seventh lens element L7, and the infrared filter L8 includes an object-side surface S15 and an image-side surface S16. Furthermore, the optical system 100 further includes an image plane S17 located on the image side of the seventh lens element L7, the image plane S17 is an imaging plane of the optical system 100, and incident light can be imaged on the image plane S17 after being adjusted by the first lens element L1, the second lens element L2, the third lens element L3, the fourth lens element L4, the fifth lens element L5, the sixth lens element L6, and the seventh lens element L7. It should be noted that the infrared filter L8 may be an infrared cut filter, and is used for filtering the interference light and preventing the interference light from reaching the image plane S17 of the optical system 100 to affect the normal imaging.

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

In some embodiments, each lens in the optical system 100 may be made of glass or plastic. The lens made of plastic material can reduce the weight of the optical system 100 and the production cost, and the 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. In some embodiments, at least two lenses in the optical system 100 are made of plastic materials with different optical characteristics, so as to facilitate correction of chromatic dispersion of the optical system 100 and improve imaging quality of the optical system 100.

It should 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, no cemented lens is formed between the lenses of the first lens L1, but the distance between the lenses is relatively fixed, in which case, the object-side surface of the lens closest to the object side is the object-side surface S1, and the image-side surface of the lens closest to the image side is the image-side surface S2. In addition, the number of lenses in the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, or the seventh lens L7 in some embodiments may also be greater than or equal to two, and a cemented lens may be formed between any two adjacent lenses, and may also be a non-cemented lens.

Further, in some embodiments, the optical system 100 satisfies the conditional expression: the | f12/f67| is less than or equal to 0.5; where f12 is a combined focal length of the first lens L1 and the second lens L2, and f67 is a combined focal length of the sixth lens L6 and the seventh lens L7. Specifically, | f (12)/f (67) | may be: 0.037, 0.088, 0.129, 0.145, 0.178, 0.207, 0.234, 0.258, 0.357 or 0.479. When the conditional expressions are met, the ratio of the combined focal length of the first lens L1 and the second lens L2 and the combined focal length of the sixth lens L6 and the seventh lens L7 can be reasonably set, so that the first lens L1 and the second lens L2 can collect light rays in a larger angle range, the sixth lens L6 and the seventh lens L7 can effectively converge the light rays at the center and at the edge of a nearby field of view, the structure of the optical system 100 is more compact, the total length of the optical system 100 can be shortened, and the requirement of miniaturization design of electronic equipment can be met; in addition, the sixth lens element L6 and the seventh lens element L7 can also effectively correct the aberration generated by the first lens element L1 and the second lens element L2, which is favorable for improving the imaging quality of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: l (R51-R52)/(R51 + R52) l is less than or equal to 100; wherein, R51 is a curvature radius of the object-side surface S9 of the fifth lens element L5 at the optical axis 110, and R52 is a curvature radius of the image-side surface S10 of the fifth lens element L5 at the optical axis 110. Specifically, | (R51-R52)/(R51 + R52) | may be: 0.044, 0.098, 0.139, 0.155, 0.181, 0.201, 0.222, 0.315, 0.952 or 97.825. When the conditional expressions are satisfied, the surface shapes of the object-side surface S9 and the image-side surface S10 of the fifth lens L5 can be reasonably configured, so that the surface shape of the fifth lens L5 is not too gentle or too curved, which is beneficial for the fifth lens L5 to correct the aberration of the optical system 100, and improves the imaging quality of the optical system 100. If the optical aberration correction is out of the range of the conditional expression, the surface shape of the fifth lens L5 will be too gentle, which will result in too small light deflection degree and is not beneficial to aberration correction of the optical system 100, or the surface shape of the fifth lens L5 will be too curved, which will result in increased difficulty in lens molding and increase the manufacturing cost of the optical system 100. Further, in some embodiments, the optical system 100 satisfies the conditional expression: the absolute value (R51-R52)/(R51 + R52) is more than or equal to 0.04 and less than or equal to 0.23. When the above conditional expressions are satisfied, the effect of correcting the aberration of the optical system 100 by the fifth lens L5 can be made better.

In some embodiments, the optical system 100 satisfies the conditional expression: l (R21-R22)/(R21 + R22) l is less than or equal to 30; wherein, R21 is a curvature radius of the object-side surface S3 of the second lens element L2 at the optical axis 110, and R22 is a curvature radius of the image-side surface S4 of the second lens element L2 at the optical axis 110. Specifically, | (R21-R22)/(R21 + R22) | may be: 0.271, 0.451, 0.656, 1.337, 5.628, 13.010, 15.369, 24.530, 25.012, or 28.576. When the above conditional expressions are satisfied, the surface shapes of the object-side surface S3 and the image-side surface S4 of the second lens L2 can be configured reasonably, so that the surface shape of the second lens L2 is not too gentle or too curved, which is beneficial to the second lens L2 to correct the aberration of the optical system 100, and improves the imaging quality of the optical system 100. Beyond the range of the conditional expression, the surface shape of the second lens L2 will be too gentle, which will result in too small light deflection degree, which is not favorable for aberration correction of the optical system 100, or the surface shape of the second lens L2 will be too curved, which will result in increased difficulty of lens molding and increase the manufacturing cost of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: the ratio of f/f2 to f/f4 is less than or equal to 1.5; where f is an effective focal length of the optical system 100, f2 is an effective focal length of the second lens L2, and f4 is an effective focal length of the fourth lens L4. Specifically, | f/f2+ f/f4| may be: 0.125, 0.235, 0.329, 0.422, 0.510, 0.632, 0.835, 0.993, 1.097 or 1.098. When the above conditional expressions are satisfied, the refractive powers of the second lens element L2 and the fourth lens element L4 in the optical system 100 can be reasonably configured, which is beneficial to balance the spherical aberration generated by the first lens element L1 and the second lens element L2 as a whole, thereby improving the resolution of the optical system 100 as a whole and simultaneously being beneficial to correct the aberration of the marginal field of view of the optical system 100; in addition, the second lens element L2 and the fourth lens element L4 serve as middle lens elements, and the reasonable refractive power distribution can provide sufficient beam transmission space for the object-side lens element and the image-side lens element of the optical system 100, thereby being beneficial to shortening the total system length of the optical system 100 and realizing a miniaturized design. That is, the relation is satisfied, the resolution of the optical system 100 can be improved, and the optical system 100 can have a good imaging quality while being miniaturized.

In some embodiments, the optical system 100 satisfies the conditional expression: the absolute value of f2/SAG22 is more than or equal to 15 and less than or equal to 135; where f2 is the effective focal length of the second lens L2, and SAG22 is the rise of the image-side surface S4 of the second lens L2 at the maximum effective aperture. Specifically, | f2/SAG22| may be: 17.718, 18.653, 19.204, 21.058, 35.364, 55.151, 70.154, 99.552, 102.285, or 130.559. When the above conditional expressions are satisfied, the refractive power of the second lens element L2 and the shape of the image-side surface S4 of the second lens element L2 can be reasonably configured, which is beneficial to correcting chromatic aberration and spherical aberration of the optical system 100, thereby improving the imaging quality of the optical system 100; meanwhile, the surface shape of the second lens L2 is not too gentle, which is beneficial to improving the light converging capability of the optical system 100, thereby being beneficial to shortening the total system length of the optical system 100 and realizing the miniaturized design.

In some embodiments, the optical system 100 satisfies the conditional expression: the absolute value of f5/SAG52 is more than or equal to 50 and less than or equal to 740; where f5 is the effective focal length of the fifth lens L5, and SAG52 is the rise of the image side surface S10 of the fifth lens L5 at the maximum effective aperture. Specifically, | f5/SAG52| may be: 64.860, 100.258, 242.862, 263.147, 300.364, 421.213, 637.808, 666.154, 680.367, or 735.050. When the above conditional expressions are satisfied, the refractive power of the fifth lens element L5 and the surface shape of the image-side surface S10 of the fifth lens element L5 can be reasonably configured, which is beneficial to correcting chromatic aberration and spherical aberration of the optical system 100, thereby improving the imaging quality of the optical system 100; meanwhile, the surface shape of the fifth lens L5 is not too gentle, which is beneficial to improving the light converging capability of the optical system 100, so that the total system length of the optical system 100 is beneficial to being shortened, and the miniaturization design is realized.

In some embodiments, the optical system 100 satisfies the conditional expression: the | SAG22/SAG52| is less than or equal to 2; where SAG22 is the saggital height of the image-side surface S4 of the second lens L2 at the maximum effective aperture, and SAG52 is the saggital height of the image-side surface S10 of the fifth lens L5 at the maximum effective aperture. Specifically, | SAG22/SAG52| may be: 0.433, 0.465, 0.495, 0.551, 0.688, 0.842, 1.132, 1.366, 1.391, or 1.420. When the conditional expression is satisfied, the rise ratio of the second lens L2 to the fifth lens L5 can be reasonably configured, which is beneficial to balancing the spherical aberration of the optical system 100 and improving the overall resolving power of the optical system 100; meanwhile, due to the reasonable design of the surface types of the second lens L2 and the fifth lens L5, the sixth lens L6 and the seventh lens L7 on the image side can effectively correct the aberration of the marginal field generated by the first lens L1 and the second lens L2 on the object side; in addition, the second lens L2 and the fifth lens L5 are not excessively curved in surface shape, and provide a sufficient space for arrangement between the lenses, thereby contributing to shortening the total length of the optical system 100 and realizing a miniaturized design. That is, satisfying the relational expression is advantageous for the optical system 100 to have a small-sized design and a good imaging quality.

In some embodiments, at least one of the object-side surface S13 and the image-side surface S14 of the seventh lens L7 has an inflection point, and the optical system 100 satisfies the following conditional expression: 1 is less than or equal to (| SAG71| + | SAG72 |)/CT 7 is less than or equal to 2; where SAG71 is the saggital height of the object-side surface S13 of the seventh lens L7 at the maximum effective aperture, SAG72 is the saggital height of the image-side surface S14 of the seventh lens L7 at the maximum effective aperture, and CT7 is the thickness of the seventh lens L7 on the optical axis 110. Specifically, (| SAG71| + | SAG72 |)/CT 7 may be: 1.038, 1.050, 1.079, 1.332, 1.501, 1.753, 1.767, 1.816, 1.874, or 1.909. The seventh lens L7 is provided with an inflection point, which is a lens closest to the imaging surface of the optical system 100, so that the beam deflection force reaching the imaging surface of the optical system 100 can be more uniform, and the distortion and the field curvature generated by each lens on the object side of the seventh lens L7 can be corrected; when the above conditional expressions are satisfied, the thickness and the surface shape of the seventh lens L7 can be reasonably configured, so that the seventh lens L7 is not too thin or too thick, and the surface shape of the seventh lens L7 is not too gentle or too curved, which is beneficial to reducing the incident angle of light on the image plane and reducing the sensitivity of the optical system 100. If the upper limit of the conditional expression is exceeded, the edge of the seventh lens L7 becomes too thick, which tends to increase field curvature aberration and cause field curvature. Below the lower limit of the conditional expression, if the edge of the seventh lens L7 is too thin, effective deflection and convergence cannot be achieved for the light in the edge field, so that it is difficult to reduce the incident angle of the light at the edge of the image plane S17, and further increase the dark angle.

In some embodiments, the optical system 100 satisfies the conditional expression: f is more than or equal to 3.7mm and less than or equal to 4.6mm, wherein f is the effective focal length of the optical system 100. Satisfying the above conditional expressions, the optical system 100 has a longer focal length, and can satisfy the shooting requirements of more scenes.

In some embodiments, the optical system 100 satisfies the conditional expression: TTL is not less than 4.6mm and not more than 5.4mm, wherein TTL is the distance between the object side surface S1 of the first lens element L1 and the image side surface S14 of the seventh lens element L7 on the optical axis 110. Satisfying the above conditional expressions, the optical system 100 has a short total optical length, and is advantageous for realizing a compact design.

In some embodiments, the optical system 100 satisfies the conditional expression: FNO is not less than 1.6 and not more than 2.2, wherein FNO is the f-number of the optical system 100. Satisfying the above conditional expressions, the optical system 100 has a large aperture and can have good imaging quality even in a low-light environment.

In some embodiments, the optical system 100 satisfies the conditional expression: the FOV is more than or equal to 76 degrees and less than or equal to 88 degrees, wherein, the FVO is the maximum field angle of the optical system 100. Satisfying the above conditional expressions, the optical system 100 has a large angle of view, and can acquire more scene information.

In some embodiments, the optical system 100 satisfies the conditional expression: imgH =3.59mm, where ImgH is half the image height corresponding to the maximum field angle of the optical system 100. Satisfying the above conditional expressions, the optical system 100 has a larger image plane, can match with a large-sized photosensitive element, and realizes high-pixel imaging, thereby satisfying the shooting requirements of more scenes.

The reference wavelengths of the effective focal length and the combined focal length are 555nm.

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

First embodiment

Referring to fig. 1 and fig. 2, fig. 1 is a schematic structural diagram of the optical system 100 in the first embodiment, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with positive refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with positive refractive power, a sixth lens element L6 with positive refractive power, and a seventh lens element L7 with negative refractive power. Fig. 2 is a graph of 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 position near the optical axis 110 and convex at the circumference;

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

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 and convex at the peripheral region;

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 S11 of the sixth lens element L6 is convex at a paraxial region 110 and concave at a peripheral region;

the image-side surface S12 of the sixth lens element L6 is concave at the paraxial region 110 and convex at the peripheral region;

the object-side surface S13 of the seventh lens element L7 is convex at a paraxial region 110 and convex at a peripheral region;

the image-side surface S14 of the seventh lens element L7 is concave at the paraxial region 110 and convex at the 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, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are aspheric.

It should be noted that in the present application, when a surface of the lens is described as being convex at a position near the optical axis 110 (a central region of the surface), it can be understood that a region of the surface of the lens near the optical axis 110 is convex. When a surface of a lens is described as being concave at the circumference, it is understood that the surface is concave in the region near the maximum effective radius. For example, when the surface is convex at a paraxial region 110 and also convex at a peripheral region, the shape of the surface from the center (the intersection of the surface with the optical axis 110) to the edge direction may be purely convex; or a convex shape at the center is firstly transited to a concave shape, and then becomes a convex shape near the maximum effective radius. Here, examples are given only to illustrate the relationship between the optical axis 110 and the circumference, and the various shapes of the surface (concave-convex relationship) 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, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are all made of plastic.

Further, the optical system 100 satisfies the conditional expression: i f12/f67| =0.037; where f12 is a combined focal length of the first lens L1 and the second lens L2, and f67 is a combined focal length of the sixth lens L6 and the seventh lens L7. When the conditional expressions are met, the ratio of the combined focal length of the first lens L1 and the second lens L2 and the combined focal length of the sixth lens L6 and the seventh lens L7 can be reasonably set, so that the first lens L1 and the second lens L2 can collect light rays in a larger angle range, the sixth lens L6 and the seventh lens L7 can effectively converge the light rays at the center and at the edge of a nearby field of view, the structure of the optical system 100 is more compact, the total length of the optical system 100 can be shortened, and the requirement of miniaturization design of electronic equipment can be met; in addition, the sixth lens element L6 and the seventh lens element L7 can also effectively correct the aberration generated by the first lens element L1 and the second lens element L2, which is favorable for improving the imaging quality of the optical system 100.

The optical system 100 satisfies the conditional expression: l (R51-R52)/(R51 + R52) | =0.139; wherein, R51 is a curvature radius of the object-side surface S9 of the fifth lens element L5 at the optical axis 110, and R52 is a curvature radius of the image-side surface S10 of the fifth lens element L5 at the optical axis 110. When the conditional expressions are satisfied, the surface shapes of the object-side surface S9 and the image-side surface S10 of the fifth lens L5 can be reasonably configured, so that the surface shape of the fifth lens L5 is not too gentle or too curved, which is beneficial for the fifth lens L5 to correct the aberration of the optical system 100, and improves the imaging quality of the optical system 100.

The optical system 100 satisfies the conditional expression: l (R21-R22)/(R21 + R22) | =24.530; wherein R21 is a curvature radius of the object-side surface S3 of the second lens element L2 at the optical axis 110, and R22 is a curvature radius of the image-side surface S4 of the second lens element L2 at the optical axis 110. When the above conditional expressions are satisfied, the surface shapes of the object-side surface S3 and the image-side surface S4 of the second lens L2 can be configured reasonably, so that the surface shape of the second lens L2 is not too gentle or too curved, which is beneficial to the second lens L2 to correct the aberration of the optical system 100, and improves the imaging quality of the optical system 100.

The optical system 100 satisfies the conditional expression: i f/f2+ f/f4 i =1.097; where f is an effective focal length of the optical system 100, f2 is an effective focal length of the second lens L2, and f4 is an effective focal length of the fourth lens L4. When the above conditional expressions are satisfied, the refractive powers of the second lens element L2 and the fourth lens element L4 in the optical system 100 can be reasonably configured, which is beneficial to balance the spherical aberration generated by the first lens element L1 and the second lens element L2 as a whole, thereby improving the resolution of the optical system 100 as a whole and simultaneously being beneficial to correct the aberration of the marginal field of view of the optical system 100; in addition, the second lens element L2 and the fourth lens element L4 serve as middle lens elements, and the reasonable refractive power distribution can provide sufficient beam transmission space for the object-side lens element and the image-side lens element of the optical system 100, thereby being beneficial to shortening the total system length of the optical system 100 and realizing a miniaturized design. That is, the relational expression is satisfied, and the resolving power of the optical system 100 can be improved, so that the optical system 100 can have good imaging quality while being miniaturized.

The optical system 100 satisfies the conditional expression: i f2/SAG22 i =17.718; where f2 is the effective focal length of the second lens L2, and SAG22 is the rise of the image-side surface S4 of the second lens L2 at the maximum effective aperture. When the above conditional expressions are satisfied, the refractive power of the second lens element L2 and the shape of the image-side surface S4 of the second lens element L2 can be reasonably configured, which is beneficial to correcting chromatic aberration and spherical aberration of the optical system 100, thereby improving the imaging quality of the optical system 100; meanwhile, the surface shape of the second lens L2 is not too gentle, which is beneficial to improving the light converging capability of the optical system 100, thereby being beneficial to shortening the total system length of the optical system 100 and realizing the miniaturized design.

The optical system 100 satisfies the conditional expression: i f5/SAG52 i =637.809; where f5 is the effective focal length of the fifth lens L5, and SAG52 is the rise of the image side surface S10 of the fifth lens L5 at the maximum effective aperture. When the above conditional expressions are satisfied, the refractive power of the fifth lens element L5 and the surface shape of the image-side surface S10 of the fifth lens element L5 can be reasonably configured, which is beneficial to correcting chromatic aberration and spherical aberration of the optical system 100, thereby improving the imaging quality of the optical system 100; meanwhile, the surface shape of the fifth lens L5 is not too gentle, which is beneficial to improving the light converging capability of the optical system 100, so that the total system length of the optical system 100 is beneficial to being shortened, and the miniaturization design is realized.

The optical system 100 satisfies the conditional expression: i SAG22/SAG52| =1.366; where SAG22 is the saggital height of the image-side surface S4 of the second lens L2 at the maximum effective aperture, and SAG52 is the saggital height of the image-side surface S10 of the fifth lens L5 at the maximum effective aperture. When the conditional expression is satisfied, the rise ratio of the second lens L2 to the fifth lens L5 can be reasonably configured, which is beneficial to balancing the spherical aberration of the optical system 100 and improving the overall resolving power of the optical system 100; meanwhile, due to the reasonable design of the surface types of the second lens L2 and the fifth lens L5, the sixth lens L6 and the seventh lens L7 on the image side can effectively correct the aberration of the marginal field generated by the first lens L1 and the second lens L2 on the object side; in addition, the second lens L2 and the fifth lens L5 have the surface shapes that are not excessively curved, and provide a sufficient space for arrangement between the lenses, thereby contributing to shortening the total system length of the optical system 100 and realizing a miniaturized design. That is, satisfying the relational expression is advantageous for the optical system 100 to have a small-sized design and a good imaging quality.

At least one of the object-side surface S13 and the image-side surface S14 of the seventh lens L7 has an inflection point, and the optical system 100 satisfies the conditional expression: (| SAG71| + | SAG72 |)/CT 7=1.038; where SAG71 is the saggital height of the object-side surface S13 of the seventh lens L7 at the maximum effective aperture, SAG72 is the saggital height of the image-side surface S14 of the seventh lens L7 at the maximum effective aperture, and CT7 is the thickness of the seventh lens L7 on the optical axis 110. The seventh lens L7 is provided with an inflection point, which is a lens closest to the imaging surface of the optical system 100, so that the beam deflection force reaching the imaging surface of the optical system 100 can be more uniform, and the distortion and the field curvature generated by each lens on the object side of the seventh lens L7 can be corrected; when the above conditional expressions are satisfied, the thickness and the surface shape of the seventh lens L7 can be reasonably configured, so that the seventh lens L7 is not too thin or too thick, and the surface shape of the seventh lens L7 is not too gentle or too curved, which is beneficial to reducing the incident angle of light on the image plane and reducing the sensitivity of the optical system 100.

In addition, the parameters of the optical system 100 are given in table 1. Here, the image plane S17 in table 1 may be understood as an imaging plane of the optical system 100. Elements from the object plane (not shown) to the image plane S17 are sequentially arranged in the order of 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. The surface number S1 and the surface number S2 are 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 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 value is the distance from the image-side surface to the rear surface along the image-side direction of the lens element along the optical axis 110.

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

In the first embodiment, the effective focal length f =4.01mm, the f-number FNO =1.68, the maximum field angle FOV =83 °, the total optical length TTL =5.38mm, the half of the image height ImgH corresponding to the maximum field angle is =3.594mm, and the distance DL =4.32mm from the object-side surface S1 of the first lens L1 to the image-side surface S14 of the seventh lens L7 on the optical axis 110. In the first embodiment and other embodiments, the f-number of the optical system 100 satisfies FNO ≦ 2.2, and it can be seen that the optical system 100 has the characteristic of a large f-number.

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 of the optical system 100 coincides with the photosensitive surface of the photosensitive element. At this time, the effective pixel area on the imaging plane of the optical system 100 has a horizontal direction and a diagonal direction, the FOV can be understood as the maximum field angle of the optical system 100 in the diagonal direction, and ImgH can be understood as a half of the length of the effective pixel area on the imaging plane of the optical system 100 in the diagonal direction.

The reference wavelength of the focal length of each lens was 555nm, and the reference wavelengths of the refractive index and the abbe number of each lens were 587.56nm (d-line), which is the same for the other examples.

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 to S14 represent image side surfaces or object side surfaces S1 to S14, 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 sextic aspheric coefficient, A8 represents an octa aspheric coefficient, and so on. In addition, the aspherical surface coefficient formula is as follows:

where 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 profile formula.

TABLE 2

In addition, fig. 2 includes a Longitudinal Spherical Aberration diagram (Longitudinal Spherical Aberration) of the optical system 100, which shows the deviation of the converging focal points of the light rays of different wavelengths after passing through the lens. The ordinate of the longitudinal spherical aberration diagram represents Normalized Pupil coordinates (Normalized Pupil Coordinator) from the Pupil center to the Pupil edge, and the abscissa represents the distance (in mm) from the imaging plane to the intersection of the ray with 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 speckle or the chromatic halo in the imaging picture is effectively suppressed. FIG. 2 also includes a field curvature diagram (ASTIGMATIC FIELD CURVES) for optical system 100, where the S curve represents sagittal field curvature at 555nm and the T curve represents meridional field curvature at 555nm. As can be seen from the figure, the field curvature of the optical system 100 is small, the field curvature and astigmatism of each field are well corrected, and the center and the edge of each field have clear images. Fig. 2 also includes a DISTORTION map (distorsion) of the optical system 100, which shows that 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, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with positive refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with positive refractive power, a sixth lens element L6 with positive refractive power, and a seventh lens element L7 with negative refractive power. Fig. 4 is a graph of longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the second embodiment, which is shown from left to right.

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

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

TABLE 3

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

TABLE 4

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

\|f12/f67\|	0.129	\|f2/SAG22\|	19.204
				\|(R51-R52)/(R51+R52)\|	0.222	\|f5/SAG52\|	421.213
\|(R21-R22)/(R21+R22)\|	13.010	\|SAG22/SAG52\|	1.420
				\|f/f2+f/f4\|	1.098	(\|SAG71\|+\|SAG72\|)/CT7	1.079

in addition, as can be seen from the aberration diagram in fig. 4, the longitudinal spherical aberration, curvature of field, 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, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, a sixth lens element L6 with positive refractive power, and a seventh lens element L7 with negative refractive power. Fig. 6 is a graph of longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the third embodiment, from left to right.

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

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

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

the image-side surface S12 of the sixth lens element L6 is convex at a paraxial region 110 and convex at a peripheral region;

the object-side surface S13 of the seventh lens element L7 is concave at a paraxial region 110 and convex at a peripheral region;

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

TABLE 5

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

TABLE 6

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

\|f12/f67\|	0.258	\|f2/SAG22\|	130.559
				\|(R51-R52)/(R51+R52)\|	0.044	\|f5/SAG52\|	735.050
\|(R21-R22)/(R21+R22)\|	0.271	\|SAG22/SAG52\|	0.688
				\|f/f2+f/f4\|	0.125	(\|SAG71\|+\|SAG72\|)/CT7	1.753

in addition, as can be seen from the aberration diagram in fig. 6, the longitudinal spherical aberration, curvature of field, 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, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with positive refractive power, a sixth lens element L6 with positive refractive power, and a seventh lens element L7 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.

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

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

TABLE 7

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

TABLE 8

\|f12/f67\|	0.478548	\|f2/SAG22\|	99.55188
				\|(R51-R52)/(R51+R52)\|	0.1808	\|f5/SAG52\|	242.8625
\|(R21-R22)/(R21+R22)\|	28.57595	\|SAG22/SAG52\|	0.495098
				\|f/f2+f/f4\|	0.632268	(\|SAG71\|+\|SAG72\|)/CT7	1.816302

in addition, as can be seen from the aberration diagram in fig. 8, the longitudinal spherical aberration, curvature of field, 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, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with negative refractive power, a sixth lens element L6 with positive refractive power, and a seventh lens element L7 with negative refractive power. Fig. 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.

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

the image-side surface S10 of the fifth lens element L5 is concave at a paraxial region 110 and convex at a peripheral region;

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

\|f12/f67\|	0.207	\|f2/SAG22\|	55.151
				\|(R51-R52)/(R51+R52)\|	97.825	\|f5/SAG52\|	64.860
\|(R21-R22)/(R21+R22)\|	0.656	\|SAG22/SAG52\|	0.433
				\|f/f2+f/f4\|	0.329	(\|SAG71\|+\|SAG72\|)/CT7	1.909

in addition, as can be seen from the aberration diagram in fig. 10, the longitudinal spherical aberration, curvature of field, 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. 11, in some embodiments, the optical system 100 may be assembled with the photosensitive element 210 to form the image capturing module 200. At this time, the light-sensing surface of the light-sensing element 210 can be regarded as the image surface S17 of the optical system 100. The image capturing module 200 may further include an infrared filter L8, and the infrared filter L8 is disposed between the image side surface S14 and the image surface S17 of the seventh lens element L7. Specifically, the photosensitive element 210 may be a Charge Coupled Device (CCD) or a Complementary Metal-Oxide Semiconductor (CMOS) Device. The optical system 100 is adopted in the image capturing module 200, and the optical system 100 has a compact structure, so that the requirement of miniaturization design of the image capturing module 200 can be met.

Referring to fig. 11 and 12, in some embodiments, the image capturing module 200 may be applied to an electronic device 300, which includes a housing 310, and the image capturing module 200 is disposed in the housing 310. Specifically, the electronic apparatus 300 may be, but is not limited to, a wearable device such as a smart watch or an onboard image capturing apparatus such as a cellular phone, a video phone, a smart phone, an electronic book reader, and a vehicle data recorder. When the electronic device 300 is a smartphone, the housing 310 may be a middle frame of the electronic device 300. The image capturing module 200 is adopted in the electronic device 300, so that the optical system 100 has a compact structure, and the requirement of miniaturization design of the electronic device 300 can be met.

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

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

Claims

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

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

a third lens element with refractive power;

and the optical system satisfies the following conditional expression:

|f12/f67|≤0.5；

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

|(R51-R52)/(R51+R52)|≤100；

wherein R51 is a curvature radius of an object-side surface of the fifth lens element at an optical axis, and R52 is a curvature radius of an image-side surface of the fifth lens element at the optical axis.

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

|(R21-R22)/(R21+R22)|≤30；

wherein R21 is a curvature radius of an object-side surface of the second lens element at the optical axis, and R22 is a curvature radius of an image-side surface of the second lens element at the optical axis.

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

|f/f2+f/f4|≤1.5；

wherein f is an effective focal length of the optical system, f2 is an effective focal length of the second lens, and f4 is an effective focal length of the fourth lens.

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

15≤|f2/SAG22|≤135；

where f2 is the effective focal length of the second lens and SAG22 is the rise of the image side of the second lens at the maximum effective aperture.

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

50≤|f5/SAG52|≤740；

wherein f5 is the effective focal length of the fifth lens, and SAG52 is the rise of the image side of the fifth lens at the maximum effective aperture.

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

|SAG22/SAG52|≤2；

wherein SAG22 is the saggital height of the image side of the second lens at the maximum effective aperture and SAG52 is the saggital height of the image side of the fifth lens at the maximum effective aperture.

8. The optical system according to claim 1, wherein an inflection point exists on at least one of an object-side surface and an image-side surface of the seventh lens, and the following conditional expression is satisfied:

1≤(|SAG71|+|SAG72|)/CT7≤2；

wherein SAG71 is the saggital height of the object side surface of the seventh lens at the maximum effective aperture, SAG72 is the saggital height of the image side surface of the seventh lens at the maximum effective aperture, and CT7 is the thickness of the seventh lens on the optical axis.

9. An image capturing module, comprising a photosensitive element and the optical system of any one of claims 1 to 8, wherein the photosensitive element is disposed on an image side of the optical system.

10. An electronic device, comprising a housing and the image capturing module of claim 9, wherein the image capturing module is disposed on the housing.