CN114740596B

CN114740596B - Optical system, image capturing module and electronic equipment

Info

Publication number: CN114740596B
Application number: CN202210282979.0A
Authority: CN
Inventors: 李翔宇; 李明; 徐标
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2022-03-22
Filing date: 2022-03-22
Publication date: 2023-09-05
Anticipated expiration: 2042-03-22
Also published as: CN114740596A

Abstract

The invention relates to an optical system, an image capturing module and electronic equipment. The optical system includes: the first 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; the second lens element with negative refractive power has a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region; the object side surface of the third lens is a convex surface at a paraxial region; the fourth lens element has a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region; the fifth lens element with a concave image-side surface at a paraxial region; the sixth lens element with positive refractive power has a convex object-side surface at a paraxial region and a convex image-side surface at a paraxial region; the seventh lens element with negative refractive power has a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region; the optical system satisfies: imgH is less than or equal to 7.9mm and is less than or equal to FNO ² TTL is less than or equal to 8.4mm. The optical system has the characteristics of large aperture and large image plane, thereby realizing good imaging quality.

Description

Optical system, image capturing module and electronic equipment

Technical Field

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

Background

With rapid development of imaging technology, more and more electronic devices such as smart phones, tablet computers, electronic readers and the like are configured with imaging lenses to have an imaging function. The performance of the camera lens greatly influences the product competitiveness of the electronic equipment, and the requirements of the industry on the performance of the camera lens of the electronic equipment are also higher. The imaging lens with good imaging quality can improve the definition of shooting, so that the shooting experience of a user is improved. However, the imaging quality of the optical system in the imaging lens at present is still to be improved.

Disclosure of Invention

Based on this, it is necessary to provide an optical system, an image capturing module and an electronic device, so as to improve the imaging quality of the optical system.

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

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

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

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

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

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

and the optical system satisfies the following conditional expression:

7.9mm≤FNO*ImgH ² /TTL≤8.4mm；

wherein FNO is the f-number of the optical system, imgH is half of the image height corresponding to the maximum field angle of the optical system, and TTL is the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis, namely the total optical length of the optical system.

In the optical system, the first lens has positive refractive power, and the convex and concave surfaces of the first lens at the paraxial region are matched with the first lens, so that light rays can be effectively converged, and the total length of the system is shortened. The second lens element with negative refractive power has positive refractive power, which is beneficial to correcting on-axis spherical aberration of the system, thereby improving imaging quality of the system. The convex-concave surface type of the first lens at the paraxial region is matched with the convex-concave surface type of the second lens at the paraxial region, so that light can be smoothly transited to each lens at the image side of the second lens, the burden of deflecting light by each lens at the image side of the second lens can be reduced, the sensitivity of the system can be reduced, and the imaging quality of the system can be improved. The planar configuration of the first lens element and the second lens element allows light to smoothly transition, and is beneficial to further compressing the total length of the system and realizing a compact design by matching the positive refractive power of the sixth lens element with the convex-convex shape of the sixth lens element at the paraxial region and the concave-surface shape of the seventh lens element at the paraxial region. The positive refractive power of the sixth lens element and the negative refractive power of the seventh lens element cooperate to facilitate correcting the on-axis spherical aberration of the system. The negative refractive power of the seventh lens element is beneficial to correcting the field curvature of the system, and the image side surface of the seventh lens element is concave at a paraxial region, which is beneficial to shortening the back focal length of the system, correcting the astigmatic aberration and field curvature of the system and enlarging the imaging surface of the system.

When the above conditional expression is satisfied, the f-number, half image height and optical total length of the system can be reasonably configured, the total length of the system is effectively compressed, the miniaturized design is realized, meanwhile, the system can obtain large aperture and large image surface characteristics, the system can also have good imaging quality in low light environments such as night scenes, rainy days and starry sky, meanwhile, the system can obtain more scene contents, the imaging information of the system is enriched, and in addition, the system is facilitated to be matched with photosensitive elements with larger size to obtain high resolution.

The imaging system has the characteristics of the surface type and the refractive power, and meets the condition expression, the aberration of the system can be effectively corrected, and the imaging system has the characteristics of large aperture and large image surface, so that good imaging quality is obtained, and meanwhile, the total length of the system is effectively compressed, thereby being beneficial to realizing miniaturization design.

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

1.7≤CT3/D34≤4；

wherein CT3 is the thickness of the third lens element on the optical axis, i.e. the center thickness of the third lens element, and D34 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. When the above conditional expression is satisfied, the center thickness of the third lens and the air interval between the third lens and the fourth lens can be reasonably configured, so that astigmatism generated by the third lens is effectively corrected, the imaging quality of the system is further improved, the forming difficulty of the third lens and the assembling difficulty of the third lens and the fourth lens are reduced, and the manufacturing yield of the system is improved.

5mm≤ImgH/tan(HFOV)≤5.5mm；

wherein the HFOV is one half of the maximum field angle of the optical system. When the condition formula is met, the half image height and the half field angle of the system can be reasonably configured, the miniaturization design is realized, and meanwhile, the system is also facilitated to have the wide-angle characteristic and the large image plane characteristic, so that the system can meet the requirement of large-scale image capturing, has good optical performance, and further effectively captures details of a shot object. When the upper limit of the conditional expression is exceeded, the field angle of the system is too small, which is not beneficial to expanding the field range of the system, so that the imaging information of the system is not complete, and the shooting quality of the system is affected easily; when the angle of view of the system is lower than the lower limit of the conditional expression, the distortion of the external field is excessive, and the distortion phenomenon appears at the periphery of the image, so that the imaging quality of the system is reduced.

0.85≤f6/f≤1.1；

wherein f6 is an effective focal length of the sixth lens, and f is an effective focal length of the optical system. When the above conditional expression is satisfied, the ratio of the effective focal length of the sixth lens to the effective focal length of the system can be reasonably configured, so that the focal power contribution of the sixth lens in the system is reasonably configured, so that the sixth lens has enough refractive power to deflect light, the total length of the system is shortened, the refractive power of the sixth lens can not be excessively strong, the advanced spherical aberration of the system can be effectively corrected, the imaging quality of the system is improved, and the surface type of the sixth lens can not be excessively bent, thereby reducing the assembly and molding difficulty of the sixth lens.

0＜A53/A52≤1.1；

wherein a52 is the maximum angle between the tangential plane of the image side surface of the fifth lens and the optical axis, and a53 is the angle between the tangential plane of the image side surface of the fifth lens and the optical axis at the maximum effective aperture. When the above conditional expression is satisfied, the image side surface of the fifth lens can not be excessively bent, so that the molding and assembly yield of the fifth lens is improved, meanwhile, smooth transition of light at the fifth lens is facilitated, the light path of the system is more stable, the sensitivity of the system is reduced, and the imaging quality of the system is improved.

0＜|f7/(f1+f2)|≤0.5；

wherein f7 is an effective focal length of the seventh lens, f1 is an effective focal length of the first lens, and f2 is an effective focal length of the second lens. When the above conditional expression is satisfied, the ratio of the effective focal length of the seventh lens to the sum of the effective focal lengths of the first lens and the second lens can be reasonably configured, so that the spherical aberration contributions of the first lens, the second lens and the seventh lens are reasonably distributed, and the spherical aberration of the system is effectively corrected, so that the on-axis area of the system has good imaging quality.

4.5≤SD42/(W4+V4)≤6；

wherein SD42 is the maximum effective half-caliber of the image side surface of the fourth lens element, W4 is half of the maximum thickness of the fourth lens element in the optical axis direction, and V4 is half of the minimum thickness of the fourth lens element in the optical axis direction. When the condition is satisfied, the effective caliber and the shape of the fourth lens can be reasonably configured, so that the fourth lens can effectively balance the aberration of the system, and the sensitivity of the system is reduced, thereby being beneficial to improving the imaging quality of the system. Below the lower limit of the above conditional expression, the sensitivity of the system increases, and the engineering of the fourth lens is not facilitated. When the upper limit of the above conditional expression is exceeded, the fourth lens has difficulty in effectively correcting the field curvature aberration of the system, thereby degrading the imaging quality of the system.

2≤CT6/ET6≤3；

the CT6 is the thickness of the sixth lens element on the optical axis, i.e., the center thickness of the sixth lens element, and ET6 is the distance from the maximum effective aperture of the object-side surface of the sixth lens element to the maximum effective aperture of the image-side surface in the direction of the optical axis, i.e., the thickness of the edge of the sixth lens element. When the above conditional expression is satisfied, the ratio of the center thickness to the edge thickness of the sixth lens can be reasonably configured, so that the sixth lens can effectively balance the advanced aberration generated by the system, and meanwhile, the field curvature adjustment of the sixth lens in engineering manufacture is facilitated, and further, the imaging quality of the system is improved. In addition, the surface shape of the sixth lens is not excessively bent, so that the molding and assembly yield of the sixth lens is improved.

5mm≤f*tan(HFOV)≤6mm；

where f is the effective focal length of the optical system and HFOV is half the maximum field angle of the optical system. When the above conditional expression is satisfied, the effective focal length and half field angle of the system can be reasonably configured, so that the system has the characteristic of a large image plane, and the system can realize high pixels and high definition.

0.8≤f1/f≤1.2；

wherein f1 is an effective focal length of the first lens, and f is an effective focal length of the optical system. When the above conditional expression is satisfied, the ratio of the effective focal length of the first lens to the effective focal length of the system can be reasonably configured, so that the focal power contribution of the first lens in the system can be reasonably configured, the focal power of the first lens in the system can not be excessively strong, the first lens can effectively correct the advanced spherical aberration of the system, the imaging quality of the system is improved, and meanwhile, the first lens can have enough refractive power to converge light rays, so that the total length of the system is shortened, and the miniaturized design is facilitated.

3≤SD22/(W2+V2)≤4；

Wherein SD22 is the maximum effective half-caliber of the image side surface of the second lens, W2 is half of the maximum thickness of the second lens in the optical axis direction, and V2 is half of the minimum thickness of the second lens in the optical axis direction. When the condition is satisfied, the effective caliber and shape of the second lens can be reasonably configured, so that the second lens can effectively balance the aberration of the system, reduce the sensitivity of the system and further improve the imaging performance of the system; and is also beneficial to the molding and assembly of the second lens. When the sensitivity of the system is lower than the lower limit of the conditional expression, the sensitivity of the system is increased, which is not beneficial to engineering manufacture of the system; when the upper limit of the above conditional expression is exceeded, it is difficult for the second lens to effectively correct the field curvature aberration of the system, resulting in poor imaging performance of the system.

An image capturing module includes a photosensitive element and the optical system according to any of the above embodiments, where the photosensitive element is disposed on an image side of the optical system. The optical system is adopted in the image capturing module, the aberration of the image capturing module can be effectively corrected, and the image capturing module has the characteristics of large aperture and large image plane, so that the image capturing module has good imaging quality, and meanwhile, the miniaturized design can be realized.

An electronic device comprises a shell and the image capturing module, wherein the image capturing module is arranged on the shell. The imaging module is adopted in the electronic equipment, the aberration of the imaging module can be effectively corrected, and the imaging module has the characteristics of large aperture and large image plane, so that the electronic equipment can have good imaging quality, and meanwhile, the miniaturized design can be realized, and the occupied space of the imaging module in the electronic equipment is reduced.

Drawings

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

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

fig. 5 is a schematic structural view of an optical system in a third embodiment of the present application;

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

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

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

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

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

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

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

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

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

Detailed Description

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

In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

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

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

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

Referring to fig. 1, 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, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7. Specifically, the first lens element L1 comprises an object-side surface S1 and an image-side surface S2, the second lens element L2 comprises an object-side surface S3 and an image-side surface S4, the third lens element L3 comprises an object-side surface S5 and an image-side surface S6, the fourth lens element L4 comprises an object-side surface S7 and an image-side surface S8, the fifth lens element L5 comprises an object-side surface S9 and an image-side surface S10, the sixth lens element L6 comprises an object-side surface S11 and an image-side surface S12, and the seventh lens element L7 comprises 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 a common axis of the lenses in the optical system 100 is an optical axis of the optical system 100. In some embodiments, the optical system 100 further includes an imaging surface S17 located at the image side of the seventh lens L7, and the incident light can be imaged on the imaging surface S17 after being adjusted by the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7.

The first lens element L1 with positive refractive power has a convex object-side surface S1 at a paraxial region and a concave image-side surface S2 at a paraxial region. The second lens element L2 with negative refractive power has a convex object-side surface S3 at a paraxial region and a concave image-side surface S4 at a paraxial region. The third lens element L3 with refractive power has an object-side surface S5 of the third lens element L3 being convex at a paraxial region. The fourth lens element L4 with refractive power has a convex object-side surface S7 at a paraxial region and a concave image-side surface S8 at a paraxial region. The fifth lens element L5 with refractive power has a concave image-side surface S10 at a paraxial region of the fifth lens element L5. The sixth lens element L6 with positive refractive power has a convex object-side surface S11 at a paraxial region and a convex image-side surface S12 at a paraxial region. The seventh lens element L7 with negative refractive power has a convex object-side surface S13 at a paraxial region and a concave image-side surface S14 at a paraxial region.

In the optical system, the positive refractive power of the first lens element L1 is matched with the concave-convex surface of the first lens element L1 at the paraxial region thereof, so that light rays can be effectively converged, and the total length of the system is shortened. The negative refractive power of the second lens element L2 is beneficial to correcting the on-axis spherical aberration of the system by matching the positive refractive power of the first lens element L1, thereby improving the imaging quality of the system. The convex-concave surface type of the first lens L1 at the paraxial region is matched with the convex-concave surface type of the second lens L2 at the paraxial region, so that light can be smoothly transited to each lens on the image side of the second lens L2, the burden of deflecting light of each lens on the image side of the second lens L2 can be reduced, the sensitivity of the system can be reduced, and the imaging quality of the system can be improved. The planar configuration of the first lens element L1 and the second lens element L2 allows light to smoothly transition, and is beneficial to further compressing the overall length of the system and achieving a compact design by combining the positive refractive power of the sixth lens element L6 with the convex-convex shape of the sixth lens element L6 at the paraxial region and the concave-surface shape of the seventh lens element L7 at the image-side surface S14 at the paraxial region. The positive refractive power of the sixth lens element L6 and the negative refractive power of the seventh lens element L7 cooperate to facilitate correcting the on-axis spherical aberration of the system. The negative refractive power of the seventh lens element L7 is beneficial to correcting the curvature of field of the system, wherein the image-side surface S14 of the seventh lens element L7 is concave at a paraxial region, which is beneficial to shortening the back focal length of the system, correcting the astigmatic aberration and curvature of field of the system, and enlarging the imaging surface S17 of the system.

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 between any two lenses, for example, the stop STO is disposed on the object side of the first lens L1. In some embodiments, the optical system 100 further includes an infrared cut filter L8 disposed on the image side of the seventh lens L7, where the infrared cut filter L8 is used to filter out the interference light, and prevent the interference light from reaching the imaging surface S17 of the optical system 100 to affect normal imaging. For example, the infrared cut filter L8 is used to filter out light in the near infrared band that is easily received by the photosensitive element.

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

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

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, where the two or more lenses can form a cemented lens, a surface of the cemented lens closest to the object side may be referred to as an object side surface S1, and a surface closest to the image side may be referred to as an image side surface S2. Alternatively, the first lens L1 does not have a cemented lens, but the distance between the lenses is relatively constant, and the object side surface of the lens closest to the object side is the object side surface S1, and the image side surface of the lens closest to the image side is the image side surface S2. In addition, the number of lenses in the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, or the seventh lens L7 in some embodiments may be greater than or equal to two, and any adjacent lenses may form a cemented lens therebetween or may be a non-cemented lens.

Further, in some embodiments, the optical system 100 satisfies the conditional expression: imgH is less than or equal to 7.9mm and is less than or equal to FNO ² TTL is less than or equal to 8.4mm; here, FNO is the f-number of the optical system 100, imgH is half of the image height corresponding to the maximum field angle of the optical system 100, and TTL is the distance between the object side surface S1 of the first lens L1 and the imaging surface S17 of the optical system 100 on the optical axis. Specifically, FNO. Times. ImgH ² the/TTL can be: 7.97, 7.99, 8.01, 8.04, 8.05, 8.07, 8.12, 8.23, 8.25 or 8.36, in mm. When the above conditional expression is satisfied, the f-number, half image height and optical total length of the system can be reasonably configured, the total length of the system is effectively compressed, the miniaturized design is realized, meanwhile, the system can obtain large aperture and large image surface characteristics, the system can also have good imaging quality in low light environments such as night scenes, rainy days and starry sky, meanwhile, the system can obtain more scene contents, the imaging information of the system is enriched, and in addition, the system is facilitated to be matched with photosensitive elements with larger size to obtain high resolution.

In some embodiments, the optical system 100 satisfies the conditional expression: CT3/D34 is less than or equal to 1.7 and less than or equal to 4; wherein, CT3 is the thickness of the third lens element L3 on the optical axis, and D34 is the distance between the image side surface S6 of the third lens element L3 and the object side surface S7 of the fourth lens element L4 on the optical axis. Specifically, the CT3/D34 may be: 1.74, 1.78, 1.99, 2.12, 2.38, 2.55, 2.69, 3.02, 3.34, or 3.82. When the above conditional expression is satisfied, the center thickness of the third lens L3 and the air space between the third lens L3 and the fourth lens L4 can be reasonably configured, so as to effectively correct the astigmatism generated by the third lens L3, further improve the imaging quality of the system, and simultaneously facilitate reducing the molding difficulty of the third lens L3 and the assembling difficulty of the third lens L3 and the fourth lens L4, and improve the manufacturing yield of the system.

In some embodiments, the optical system 100 satisfies the conditional expression: imgH/tan (HFOV) is less than or equal to 5.5mm; wherein the HFOV is half the maximum field angle of the optical system 100. Specifically, imgH/tan (HFOV) may be: 5.302, 5.325, 5.343, 5.375, 5.399, 5.437, 5.441, 5.457, 5.460 or 5.463, in mm. When the condition formula is met, the half image height and the half field angle of the system can be reasonably configured, the miniaturization design is realized, and meanwhile, the system is also facilitated to have the wide-angle characteristic and the large image plane characteristic, so that the system can meet the requirement of large-scale image capturing, has good optical performance, and further effectively captures details of a shot object. When the upper limit of the conditional expression is exceeded, the field angle of the system is too small, which is not beneficial to expanding the field range of the system, so that the imaging information of the system is not complete, and the shooting quality of the system is affected easily; when the angle of view of the system is lower than the lower limit of the conditional expression, the distortion of the external field is excessive, and the distortion phenomenon appears at the periphery of the image, so that the imaging quality of the system is reduced.

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 S17 of the optical system 100 coincides with the photosensitive surface of the photosensitive element. At this time, the effective pixel area on the imaging surface S17 of the optical system 100 has a horizontal direction and a diagonal direction, and the HFOV can be understood as a half of the maximum viewing angle of the diagonal direction of the optical system 100, and the ImgH can be understood as a half of the length of the effective pixel area on the imaging surface S17 of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: f6/f is more than or equal to 0.85 and less than or equal to 1.1; where f6 is the effective focal length of the sixth lens L6, and f is the effective focal length of the optical system 100. Specifically, f6/f may be: 0.887, 0.891, 0.895, 1.001, 1.008, 1.013, 1.015, 1.017, 1.020 or 1.023. When the above conditional expression is satisfied, the ratio of the effective focal length of the sixth lens element L6 to the effective focal length of the system can be reasonably configured, so that the focal power contribution of the sixth lens element L6 in the system is reasonably configured, so that the sixth lens element L6 has enough refractive power to deflect light, the total length of the system is shortened, the refractive power of the sixth lens element L6 can not be excessively strong, the advanced spherical aberration of the system can be effectively corrected, the imaging quality of the system is improved, and the surface form of the sixth lens element L6 can not be excessively bent, thereby reducing the difficulty in assembling and molding the sixth lens element L6.

In some embodiments, the optical system 100 satisfies the conditional expression: A53/A52 is more than 0 and less than or equal to 1.1; wherein a52 is the maximum angle between the tangential plane of the image-side surface S10 of the fifth lens element L5 and the optical axis, and a53 is the angle between the tangential plane of the image-side surface S10 of the fifth lens element L5 and the optical axis. Specifically, A53/A52 may be: 0.881, 0.893, 1.002, 1.008, 1.011, 1.013, 1.029, 1.037, 1.055 or 1.062. When the above conditional expression is satisfied, the image side surface S10 of the fifth lens L5 is not excessively curved, so as to improve the molding and assembly yield of the fifth lens L5, and meanwhile, facilitate smooth transition of light rays at the fifth lens L5, so that the light path of the system is more stable, the sensitivity of the system is reduced, and further, the imaging quality of the system is improved.

In some embodiments, the optical system 100 satisfies the conditional expression: 0 < |f7/(f1+f2) | is less than or equal to 0.5; wherein f7 is an effective focal length of the seventh lens L7, f1 is an effective focal length of the first lens L1, and f2 is an effective focal length of the second lens L2. Specifically, |f7/(f1+f2) | may be: 0.110, 0.125, 0.138, 0.144, 0.159, 0.163, 0.174, 0.185, 0.190, or 0.196. When the above conditional expression is satisfied, the ratio of the effective focal length of the seventh lens L7 to the sum of the effective focal lengths of the first lens L1 and the second lens L2 can be reasonably configured, so that the spherical aberration contributions of the first lens L1, the second lens L2 and the seventh lens L7 are reasonably distributed, and the spherical aberration of the system is effectively corrected, so that the on-axis area of the system has good imaging quality.

In some embodiments, the optical system 100 satisfies the conditional expression: SD 42/(W4+V4) is less than or equal to 4.5 and less than or equal to 6; the SD42 is the maximum effective half-caliber of the image side surface S8 of the fourth lens element L4, W4 is half of the maximum thickness of the fourth lens element L4 in the optical axis direction, and V4 is half of the minimum thickness of the fourth lens element L4 in the optical axis direction. Specifically, SD 42/(w4+v4) may be: 4.708, 4.811, 4.923, 5.024, 5.128, 5.245, 5.369, 5.447, 5.528 or 5.713. When the above conditional expression is satisfied, the effective caliber and shape of the fourth lens L4 can be reasonably configured, so that the fourth lens L4 can effectively balance the aberration of the system, and reduce the sensitivity of the system, thereby being beneficial to improving the imaging quality of the system. Below the lower limit of the above conditional expression, the sensitivity of the system increases, and the engineering manufacture of the fourth lens L4 is not facilitated. When the upper limit of the above conditional expression is exceeded, it is difficult for the fourth lens L4 to effectively correct the field curvature aberration of the system, thereby reducing the imaging quality of the system.

In some embodiments, the optical system 100 satisfies the conditional expression: CT6/ET6 is more than or equal to 2 and less than or equal to 3; the CT6 is the thickness of the sixth lens element L6 on the optical axis, and ET6 is the distance from the maximum effective aperture of the object-side surface S11 of the sixth lens element L6 to the maximum effective aperture of the image-side surface S12 in the optical axis direction. Specifically, CT6/ET6 may be: 2.300, 2.323, 2.355, 2.398, 2.411, 2.455, 2.503, 2.528, 2.577, 2.601, 2.632, or 2.643. When the above conditional expression is satisfied, the ratio of the center thickness to the edge thickness of the sixth lens L6 can be reasonably configured, so that the sixth lens L6 can effectively balance the advanced aberration generated by the system, and meanwhile, the field curvature adjustment of the sixth lens L6 in engineering manufacture is facilitated, and further, the imaging quality of the system is improved. In addition, the surface shape of the sixth lens L6 is not excessively bent, so that the molding and assembly yield of the sixth lens L6 is improved.

In some embodiments, the optical system 100 satisfies the conditional expression: f is less than or equal to 5mm and tan (HFOV) is less than or equal to 6mm; where f is the effective focal length of the optical system 100 and HFOV is half the maximum field angle of the optical system 100. Specifically, f tan (HFOV) may be: 5.010, 5.025, 5.047, 5.072, 5.099, 5.110, 5.123, 5.132, 5.164 or 5.171. When the above conditional expression is satisfied, the effective focal length and half field angle of the system can be reasonably configured, so that the system has the characteristic of a large image plane, and the system can realize high pixels and high definition.

In some embodiments, the optical system 100 satisfies the conditional expression: f1/f is more than or equal to 0.8 and less than or equal to 1.2; where f1 is the effective focal length of the first lens L1, and f is the effective focal length of the optical system 100. Specifically, f1/f may be: 1.048, 1.052, 1.063, 1.088, 1.095, 1.104, 1.127, 1.135, 1.144 or 1.151. When the above conditional expression is satisfied, the ratio of the effective focal length of the first lens L1 to the effective focal length of the system can be reasonably configured, so that the focal power contribution of the first lens L1 in the system can be reasonably configured, the focal power of the first lens L1 in the system can not be excessively strong, the advanced spherical aberration of the system can be effectively corrected by the first lens L1, the imaging quality of the system is improved, and meanwhile, the first lens L1 can have enough refractive power to converge light rays, so that the total length of the system is shortened, and the miniaturized design is facilitated.

In some embodiments, the optical system 100 satisfies the conditional expression: SD 22/(W2+V2) is less than or equal to 3 and less than or equal to 4; the SD22 is the maximum effective half-caliber of the image side surface S4 of the second lens element L2, W2 is half of the maximum thickness of the second lens element L2 in the optical axis direction, and V2 is half of the minimum thickness of the second lens element L2 in the optical axis direction. Specifically, SD 22/(w2+v2) may be: 3.182, 3.212, 3.287, 3.332, 3.355, 3.374, 3.423, 3.474, 3.510 or 3.568. When the condition is satisfied, the effective caliber and shape of the second lens L2 can be reasonably configured, so that the second lens L2 can effectively balance the aberration of the system, reduce the sensitivity of the system, and further improve the imaging performance of the system; and is also beneficial to the molding and assembly of the second lens L2. When the sensitivity of the system is lower than the lower limit of the conditional expression, the sensitivity of the system is increased, which is not beneficial to engineering manufacture of the system; when the upper limit of the above conditional expression is exceeded, it is difficult for the second lens L2 to effectively correct the curvature of field aberration of the system, resulting in poor imaging performance of the system.

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

From the above description of the embodiments, more particular embodiments and figures are set forth below in detail. Although the embodiments of the present application have been described with reference to eight lenses, the number of lenses having refractive power in the optical system 100 is not limited to seven, and the optical system 100 may include other numbers of lenses. It will be appreciated by those skilled in the art that the number of lenses making up the optical system 100 can be varied to achieve the various results and advantages described in this specification without departing from the scope of the application as claimed.

First embodiment

Referring to fig. 1 and 2, fig. 1 is a schematic structural diagram of an optical system 100 in a first embodiment, wherein 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. 2 is a graph of longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the first embodiment, from left to right, where the reference wavelength of the astigmatism graph and the distortion graph is 555nm, and other embodiments are the same.

The object side surface S1 of the first lens element L1 is convex at a paraxial region and convex at a circumferential region;

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

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

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

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

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

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

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

the object side surface S9 of the fifth lens element L5 is convex at a paraxial region and concave at a circumferential region;

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

the object side surface S11 of the sixth lens element L6 is convex at a paraxial region and concave at a circumferential region;

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

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

The image-side surface S14 of the seventh lens element L7 is concave at a paraxial region and convex at a peripheral region.

The object side surfaces and the image side surfaces of 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 are aspheric.

It should be noted that in the present application, when one surface of a lens is described as being convex at a paraxial region (a central region of the surface), it is understood that the region of the surface of the lens near the optical axis is convex. When describing a surface of a lens as concave at the circumference, it is understood that the surface is concave in the area near the maximum effective radius. For example, when the surface is convex at a paraxial region and also convex at a circumferential region, the shape of the surface from the center (the intersection of the surface and the optical axis) to the edge direction may be purely convex; or first transition from a convex shape in the center to a concave shape and then become convex near the maximum effective radius. The various shape structures (concave-convex relationship) of the surface are not entirely present here only for the sake of illustration of the relationship at the optical axis with the circumference, but other cases can be deduced from the above examples.

The materials 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 all plastics.

Further, the optical system 100 satisfies the conditional expression: FNO. ImgH ² Ttl= 8.063mm; here, FNO is the f-number of the optical system 100, imgH is half of the image height corresponding to the maximum field angle of the optical system 100, and TTL is the distance between the object side surface S1 of the first lens L1 and the imaging surface S17 of the optical system 100 on the optical axis. When the above conditional expression is satisfied, the f-number, half image height and total optical length of the system can be reasonably configured, and the total length of the system can be effectively compressed, so that the system can be obtained while the miniaturized design is realizedThe system has the characteristics of large aperture and large image surface, so that the system can have good imaging quality in low light environments such as night scenes, rainy days, starry sky and the like, can acquire more scene contents, enriches imaging information of the system, and is beneficial to matching of the system with photosensitive elements with larger sizes to obtain high resolution.

The optical system 100 satisfies the conditional expression: CT 3/d34=1.739; wherein, CT3 is the thickness of the third lens element L3 on the optical axis, and D34 is the distance between the image side surface S6 of the third lens element L3 and the object side surface S7 of the fourth lens element L4 on the optical axis. When the above conditional expression is satisfied, the center thickness of the third lens L3 and the air space between the third lens L3 and the fourth lens L4 can be reasonably configured, so as to effectively correct the astigmatism generated by the third lens L3, further improve the imaging quality of the system, and simultaneously facilitate reducing the molding difficulty of the third lens L3 and the assembling difficulty of the third lens L3 and the fourth lens L4, and improve the manufacturing yield of the system.

The optical system 100 satisfies the conditional expression: imgH/tan (HFOV) = 5.349mm; wherein the HFOV is half the maximum field angle of the optical system 100. When the condition formula is met, the half image height and the half field angle of the system can be reasonably configured, the miniaturization design is realized, and meanwhile, the system is also facilitated to have the wide-angle characteristic and the large image plane characteristic, so that the system can meet the requirement of large-scale image capturing, has good optical performance, and further effectively captures details of a shot object.

The optical system 100 satisfies the conditional expression: f6/f=0.887; where f6 is the effective focal length of the sixth lens L6, and f is the effective focal length of the optical system 100. When the above conditional expression is satisfied, the ratio of the effective focal length of the sixth lens element L6 to the effective focal length of the system can be reasonably configured, so that the focal power contribution of the sixth lens element L6 in the system is reasonably configured, so that the sixth lens element L6 has enough refractive power to deflect light, the total length of the system is shortened, the refractive power of the sixth lens element L6 can not be excessively strong, the advanced spherical aberration of the system can be effectively corrected, the imaging quality of the system is improved, and the surface form of the sixth lens element L6 can not be excessively bent, thereby reducing the difficulty in assembling and molding the sixth lens element L6.

The optical system 100 satisfies the conditional expression: a53/a52=0.938; wherein a52 is the maximum angle between the tangential plane of the image-side surface S10 of the fifth lens element L5 and the optical axis, and a53 is the angle between the tangential plane of the image-side surface S10 of the fifth lens element L5 and the optical axis. When the above conditional expression is satisfied, the image side surface S10 of the fifth lens L5 is not excessively curved, so as to improve the molding and assembly yield of the fifth lens L5, and meanwhile, facilitate smooth transition of light rays at the fifth lens L5, so that the light path of the system is more stable, the sensitivity of the system is reduced, and further, the imaging quality of the system is improved.

The optical system 100 satisfies the conditional expression: |f7/(f1+f2) |=0.192; wherein f7 is an effective focal length of the seventh lens L7, f1 is an effective focal length of the first lens L1, and f2 is an effective focal length of the second lens L2. When the above conditional expression is satisfied, the ratio of the effective focal length of the seventh lens L7 to the sum of the effective focal lengths of the first lens L1 and the second lens L2 can be reasonably configured, so that the spherical aberration contributions of the first lens L1, the second lens L2 and the seventh lens L7 are reasonably distributed, and the spherical aberration of the system is effectively corrected, so that the on-axis area of the system has good imaging quality.

The optical system 100 satisfies the conditional expression: SD 42/(w4+v4) = 5.065; the SD42 is the maximum effective half-caliber of the image side surface S8 of the fourth lens element L4, W4 is half of the maximum thickness of the fourth lens element L4 in the optical axis direction, and V4 is half of the minimum thickness of the fourth lens element L4 in the optical axis direction. When the above conditional expression is satisfied, the effective caliber and shape of the fourth lens L4 can be reasonably configured, so that the fourth lens L4 can effectively balance the aberration of the system, and reduce the sensitivity of the system, thereby being beneficial to improving the imaging quality of the system.

The optical system 100 satisfies the conditional expression: CT 6/et6=2.500; the CT6 is the thickness of the sixth lens element L6 on the optical axis, and ET6 is the distance from the maximum effective aperture of the object-side surface S11 of the sixth lens element L6 to the maximum effective aperture of the image-side surface S12 in the optical axis direction. When the above conditional expression is satisfied, the ratio of the center thickness to the edge thickness of the sixth lens L6 can be reasonably configured, so that the sixth lens L6 can effectively balance the advanced aberration generated by the system, and meanwhile, the field curvature adjustment of the sixth lens L6 in engineering manufacture is facilitated, and further, the imaging quality of the system is improved. In addition, the surface shape of the sixth lens L6 is not excessively bent, so that the molding and assembly yield of the sixth lens L6 is improved.

The optical system 100 satisfies the conditional expression: f tan (HFOV) =5.153 mm; where f is the effective focal length of the optical system 100 and HFOV is half the maximum field angle of the optical system 100. When the above conditional expression is satisfied, the effective focal length and half field angle of the system can be reasonably configured, so that the system has the characteristic of a large image plane, and the system can realize high pixels and high definition.

The optical system 100 satisfies the conditional expression: f1/f=1.102; where f1 is the effective focal length of the first lens L1, and f is the effective focal length of the optical system 100. When the above conditional expression is satisfied, the ratio of the effective focal length of the first lens L1 to the effective focal length of the system can be reasonably configured, so that the focal power contribution of the first lens L1 in the system can be reasonably configured, the focal power of the first lens L1 in the system can not be excessively strong, the advanced spherical aberration of the system can be effectively corrected by the first lens L1, the imaging quality of the system is improved, and meanwhile, the first lens L1 can have enough refractive power to converge light rays, so that the total length of the system is shortened, and the miniaturized design is facilitated.

The optical system 100 satisfies the conditional expression: SD 22/(w2+v2) =3.436; the SD22 is the maximum effective half-caliber of the image side surface S4 of the second lens element L2, W2 is half of the maximum thickness of the second lens element L2 in the optical axis direction, and V2 is half of the minimum thickness of the second lens element L2 in the optical axis direction. When the condition is satisfied, the effective caliber and shape of the second lens L2 can be reasonably configured, so that the second lens L2 can effectively balance the aberration of the system, reduce the sensitivity of the system, and further improve the imaging performance of the system; and is also beneficial to the molding and assembly of the second lens L2.

In addition, various parameters of the optical system 100 are given in table 1. Wherein the elements from the object plane (not shown) to the imaging plane S17 are sequentially arranged in the order of the elements from top to bottom in table 1. The radius Y in table 1 is the radius of curvature of the object side or image side of the corresponding plane number at the optical axis. The surface numbers S1 and S2 are the object side surface S1 and the image side surface S2 of the first lens element L1, respectively, i.e., the surface with the smaller surface number is the object side surface and the surface with the larger surface number is the image side surface in the same lens element. The first value in the "thickness" parameter row of the first lens element L1 is the thickness of the lens element on the optical axis, and the second value is the distance from the image side surface of the lens element to the rear surface in the image side direction on the optical axis.

Note that in this embodiment and the following embodiments, the optical system 100 may not be provided with the infrared cut filter L8, but the distance from the image side surface S14 to the imaging surface S17 of the seventh lens L7 remains unchanged.

In the first embodiment, the effective focal length f=5.22 mm, the optical total length ttl=6.29 mm, the maximum field angle fov= 88.84deg, and the f-number fno=1.84 of the optical system 100.

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

TABLE 1

Further, the aspherical coefficients of the image side or object side of each lens of the optical system 100 are given in table 2. Wherein the plane numbers S1-S14 represent the image side surfaces or the object side surfaces S1-S14, respectively. And K-a20 from top to bottom respectively represent types of aspherical coefficients, where K represents a conic coefficient, A4 represents four times an aspherical coefficient, A6 represents six times an aspherical coefficient, A8 represents eight times an aspherical coefficient, and so on. In addition, the aspherical coefficient formula is as follows:

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

TABLE 2

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In addition, fig. 2 includes a longitudinal spherical aberration plot (Longitudinal Spherical Aberration) of the optical system 100, the longitudinal spherical aberration plot representing the focus deviation of light rays of different wavelengths after passing through the lens, wherein the ordinate represents the normalized pupil coordinates (Normalized Pupil Coordinator) from the pupil center to the pupil edge, and the abscissa represents the focus deviation, i.e., the distance (in mm) from the imaging surface S17 to the intersection of the light rays and the optical axis. As can be seen from the longitudinal spherical aberration chart, the degree of focus deviation of the light rays of each wavelength in the first embodiment tends to be uniform, and the diffuse spots or the halos in the imaging picture are effectively suppressed. Fig. 2 also includes an astigmatic curve diagram (ASTIGMATIC FIELD CURVES) of the optical system 100, wherein the abscissa represents the focus offset, the ordinate represents the image height in mm, and the S-curve in the astigmatic curve represents the sagittal field curve at 555nm and the T-curve represents the meridional field curve at 555 nm. 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 of view are well corrected, and the center and the edge of the field of view have clear imaging. Fig. 2 also includes a DISTORTION graph (DISTORTION) of the optical system 100, where the DISTORTION graph represents DISTORTION magnitude values for different field angles, and where the abscissa represents DISTORTION value in% and the ordinate represents image height in 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 an optical system 100 in a second embodiment, wherein the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with negative refractive power, a sixth lens element L6 with positive refractive power, and a seventh lens element L7 with negative refractive power. Fig. 4 is a graph showing longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the second embodiment in order from left to right.

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

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

TABLE 3 Table 3

Further, the aspheric coefficients of the image side or the object side of each lens of the optical system 100 are given in table 4, and the definition of each parameter can be obtained from the first embodiment, which is not described herein.

TABLE 4 Table 4

From the above provided parameter information, the following data can be deduced:

FNO*ImgH ² /TTL(mm)	8.046	SD42/(W4+V4)	5.713
				CT3/D34	2.929	CT6/ET6	2.630
ImgH/tan(HFOV)(mm)	5.314	f*tan(HFOV)(mm)	5.010
				f6/f	0.911	f1/f	1.112
A53/A52	0.881	SD22/(W2+V2)	3.450
				\|f7/(f1+f2)\|	0.135

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

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

TABLE 5

Further, the aspheric coefficients of the image side or the object side of each lens of the optical system 100 are given in table 6, and the definition of each parameter can be obtained from the first embodiment, which is not described herein.

TABLE 6

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

FNO*ImgH ² /TTL(mm)	8.054	SD42/(W4+V4)	5.620
				CT3/D34	2.533	CT6/ET6	2.300
ImgH/tan(HFOV)(mm)	5.463	f*tan(HFOV)(mm)	5.171
				f6/f	0.919	f1/f	1.096
A53/A52	0.943	SD22/(W2+V2)	3.182
				\|f7/(f1+f2)\|	0.137

in addition, as is clear from the aberration diagram in fig. 6, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are all 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 an optical system 100 in a fourth embodiment, wherein 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 positive refractive power, a fifth lens element L5 with negative refractive power, a sixth lens element L6 with positive refractive power, and a seventh lens element L7 with negative refractive power. Fig. 8 is a graph showing longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the fourth embodiment in order from left to right.

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

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

TABLE 7

Further, the aspheric coefficients of the image side or the object side of each lens in the optical system 100 are given in table 8, and the definition of each parameter can be obtained from the first embodiment, which is not described herein.

TABLE 8

FNO*ImgH ² /TTL(mm)	8.006	SD42/(W4+V4)	5.081
				CT3/D34	3.818	CT6/ET6	2.643
ImgH/tan(HFOV)(mm)	5.405	f*tan(HFOV)(mm)	5.050
				f6/f	0.926	f1/f	1.048
A53/A52	1.062	SD22/(W2+V2)	3.325
				\|f7/(f1+f2)\|	0.196

in addition, as is clear from the aberration diagram in fig. 8, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are all 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 an optical system 100 in a fifth embodiment, wherein 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 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. 10 is a graph showing longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the fifth embodiment in order from left to right.

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

TABLE 9

Further, the aspheric coefficients of the image side or the object side of each lens of the optical system 100 are given in table 10, and the definition of each parameter can be obtained from the first embodiment, which is not described herein.

Table 10

in addition, as is clear from the aberration diagram in fig. 10, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are all 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 an optical system 100 in a sixth embodiment, 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. 10 is a graph showing longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the fifth embodiment in order from left to right.

In addition, the parameters of the optical system 100 are given in table 11, and the definition of the parameters can be obtained in the first embodiment, which is not described herein.

TABLE 11

Further, the aspheric coefficients of the image side or the object side of each lens of the optical system 100 are given in table 12, and the definition of each parameter can be obtained from the first embodiment, which is not described herein.

Table 12

FNO*ImgH ² /TTL(mm)	8.364	SD42/(W4+V4)	5.091
				CT3/D34	2.375	CT6/ET6	2.357
ImgH/tan(HFOV)(mm)	5.302	f*tan(HFOV)(mm)	5.148
				f6/f	1.023	f1/f	1.151
A53/A52	0.979	SD22/(W2+V2)	3.568
				\|f7/(f1+f2)\|	0.110

in addition, as is clear from the aberration diagram in fig. 12, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are all well controlled, so that the optical system 100 of this embodiment has good imaging quality.

Referring to fig. 13, 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 photosensitive surface of the photosensitive element 210 coincides with the imaging surface S17 of the optical system 100. The image capturing module 200 may further be provided with an infrared cut-off filter L8, where the infrared cut-off filter L8 is disposed between the image side surface S14 and the imaging surface S17 of the seventh lens element L7. Specifically, the photosensitive element 210 may be a charge coupled element (Charge Coupled Device, CCD) or a complementary metal oxide semiconductor device (Complementary Metal-Oxide Semiconductor Sensor, CMOS Sensor). The optical system 100 is adopted in the image capturing module 200, so that the aberration of the image capturing module 200 can be effectively corrected, and the image capturing module has the characteristics of large aperture and large image plane, thereby having good imaging quality and realizing miniaturized design.

Referring to fig. 13 and 14, in some embodiments, the image capturing module 200 can be applied to an electronic device 300, the electronic device 300 includes a housing 310, and the image capturing module 200 is disposed on the housing 310. Specifically, the electronic device 300 may be, but is not limited to, a portable telephone, a video phone, a smart phone, an electronic book reader, a vehicle-mounted image pickup device such as a car recorder, or a wearable device such as a smart watch. When the electronic device 300 is a smart phone, the housing 310 may be a middle frame of the electronic device 300. By adopting the image capturing module 200 in the electronic device 300, the aberration of the image capturing module 200 can be effectively corrected, and the electronic device 300 has the characteristics of large aperture and large image plane, so that the electronic device 300 can have good imaging quality, and meanwhile, the miniaturized design can be realized, thereby reducing the occupied space of the image capturing module 200 in the electronic device 300.

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

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

Claims

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

and the optical system satisfies the following conditional expression:

7.9mm≤FNO*ImgH ² /TTL≤8.4mm；

wherein FNO is the f-number of the optical system, imgH is half of the image height corresponding to the maximum field angle of the optical system, and TTL is the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis.

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

1.7≤CT3/D34≤4；

wherein CT3 is the thickness of the third lens element on the optical axis, and D34 is the distance between the image side surface of the third lens element and the object side surface of the fourth lens element on the optical axis.

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

5mm≤ImgH/tan(HFOV)≤5.5mm；

wherein the HFOV is one half of the maximum field angle of the optical system.

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

0.85≤f6/f≤1.1；

Wherein f6 is an effective focal length of the sixth lens, and f is an effective focal length of the optical system.

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

0＜A53/A52≤1.1；

wherein a52 is the maximum angle between the tangential plane of the image side surface of the fifth lens and the optical axis, and a53 is the angle between the tangential plane of the image side surface of the fifth lens and the optical axis at the maximum effective aperture.

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

0＜|f7/(f1+f2)|≤0.5；

wherein f7 is an effective focal length of the seventh lens, f1 is an effective focal length of the first lens, and f2 is an effective focal length of the second lens.

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

4.5≤SD42/(W4+V4)≤6；

wherein SD42 is the maximum effective half-caliber of the image side surface of the fourth lens element, W4 is half of the maximum thickness of the fourth lens element in the optical axis direction, and V4 is half of the minimum thickness of the fourth lens element in the optical axis direction.

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

2≤CT6/ET6≤3；

wherein CT6 is the thickness of the sixth lens element on the optical axis, and ET6 is the distance from the maximum effective aperture of the object-side surface of the sixth lens element to the maximum effective aperture of the image-side surface in the direction of the optical axis.

9. An image capturing module comprising a photosensitive element and the optical system of any one of claims 1-8, 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.