CN111812804B

CN111812804B - Optical system, image acquisition module and electronic equipment

Info

Publication number: CN111812804B
Application number: CN202010715977.7A
Authority: CN
Inventors: 刘彬彬; 李明; 邹海荣
Original assignee: Jiangxi Oufei Optics Co ltd; Nanchang Oufei Precision Optical Product Co ltd
Current assignee: Jiangxi Oufei Optics Co ltd; Nanchang Oufei Precision Optical Product Co ltd
Priority date: 2020-07-23
Filing date: 2020-07-23
Publication date: 2025-11-14
Anticipated expiration: 2040-07-23
Also published as: CN111812804A

Abstract

The invention relates to an optical system, an image capturing module and electronic equipment. The optical system sequentially comprises a first lens with positive refractive power, a second lens with negative refractive power, a third lens with object-side and convex surfaces, a fifth lens with negative refractive power, a sixth lens with positive refractive power, a seventh lens with negative refractive power and a concave surface at the paraxial region, wherein the first lens with positive refractive power is convex at the paraxial region, the second lens with negative refractive power is convex at the paraxial region, the third lens with refractive power is convex at the paraxial region, the fourth lens with refractive power is convex at the image-side region, the fifth lens with negative refractive power is convex at the paraxial region, the sixth lens with positive refractive power is convex at the paraxial region, the seventh lens with negative refractive power is concave at the image-side region, and the optical system satisfies the following conditional expression that TTL/(ImgH 2) is less than or equal to 0.6. When the above conditional expression is satisfied, the total system length of the optical system can be shortened to satisfy the requirement of the miniaturized design.

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 the rapid development of electronic devices such as smart phones and tablet computers, people have increasingly high requirements on the electronic devices, and not only are the electronic devices required to be provided with an optical system to have a camera function, but also the electronic devices are required to be capable of being miniaturized to have a small volume and be convenient to carry and use. However, the current optical system is generally large in size, and is difficult to meet the requirement of miniaturization design of electronic equipment when the optical system is applied to the electronic equipment.

Disclosure of Invention

Accordingly, it is necessary to provide an optical system, an image capturing module, and an electronic apparatus, which solve the problem that the conventional optical system is difficult to meet the miniaturization design requirements of the electronic apparatus.

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

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

a fifth lens element with negative refractive power;

a sixth lens element with positive refractive power having a convex object-side surface at a 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:

0.6≤TTL/(ImgH*2)≤0.8;

the TTL is the total system length of the optical system, that is, the distance between the object side surface of the first lens and the imaging surface of the optical system on the optical axis, and ImgH is half of the diagonal length of the effective pixel area of the optical system on the imaging surface.

In the optical system, the first lens element has positive refractive power, which contributes to shortening the overall system length of the optical system, and the object-side surface of the first lens element is convex at the paraxial region, so that the positive refractive power of the first lens element can be further enhanced, the optical system can be made shorter in size along the optical axis direction, and the miniaturization design of the optical system is facilitated. When the above conditional expression is satisfied, the system overall length of the optical system and the diagonal length of the effective pixel area on the imaging surface can be reasonably configured, which is favorable for shortening the system overall length of the optical system, thereby satisfying the requirement of miniaturized design.

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

38°≤FOV/2≤46°;

the FOV is the maximum field angle of the optical system in the diagonal direction of the effective pixel area on the imaging surface. When the relation is satisfied, the optical system has a large viewing angle characteristic, and can satisfy the requirement of large viewing angle shooting.

In one embodiment, the object side surface and the image side surface of each lens in the optical system are aspheric, and the optical system satisfies the following conditional expression:

1.0≤TTL/f≤1.5;

Wherein TTL is the total system length of the optical system, and f is the effective focal length of the optical system. When the relation is satisfied, the total length and the effective focal length of the optical system can be reasonably configured, so that the structural layout of the optical system is compact and reasonable, and the requirement of miniaturized design is further satisfied. And the arrangement of the aspheric surface is also beneficial to balancing chromatic aberration, spherical aberration, distortion and other aberration of the optical system under the condition of meeting the requirement of large-view shooting, so that the imaging quality of the optical system is improved.

0.75≤DL/TTL≤1.1;

Wherein DL is the distance between the object side surface of the first lens element and the image side surface of the seventh lens element on the optical axis, and TTL is the total system length of the optical system, i.e. the distance between the object side surface of the first lens element and the image plane of the optical system on the optical axis. When the relation is satisfied, the structure of the optical system can be reasonably laid out, the distance from the image side surface of the seventh lens to the imaging surface of the optical system on the optical axis is increased while the miniaturized design requirement is satisfied, and the layout of the module structure end is facilitated.

f23<0;

wherein f23 is a combined focal length of the second lens and the third lens. When the above relation is satisfied, the combined focal length of the second lens and the third lens can be reasonably configured, and the combined focal length can be matched with the positive refractive power of the first lens, so that the aberration generated by the optical system can be effectively balanced, and meanwhile, the light rays of the edge view field of the optical system can be better converged on the imaging surface. In addition, the structural layout of the optical system can be more compact, the total system length of the optical system can be shortened, and the miniaturization design can be realized.

0≤R14/f≤1;

Wherein R14 is a radius of curvature of the image side surface of the seventh lens element at the optical axis, and f is an effective focal length of the optical system. When the relation is satisfied, the radius of curvature of the image side surface of the seventh lens at the optical axis and the effective focal length of the optical system can be reasonably configured, so that the surface shape of the image side surface of the seventh lens is more gentle, the generation of curvature of field and distortion of the optical system is favorably inhibited, the imaging quality of the optical system is improved, and meanwhile, the molding difficulty of the seventh lens can be reduced. In addition, it is also advantageous to control the overall system length of the optical system so that the overall system length of the optical system is not too long.

|f6|+|f7|≤12mm;

Wherein f6 is an effective focal length of the sixth lens, and f7 is an effective focal length of the seventh lens. When the relation is satisfied, the effective focal lengths of the sixth lens and the seventh lens can be reasonably configured so as to better balance spherical aberration generated by each lens on the object side of the sixth lens, and meanwhile, aberration of a field of view at the edge of the optical system can be better corrected, so that imaging quality of the optical system is improved. In addition, the total length of the optical system is also reduced, and the miniaturization design is realized.

|V2-V1|≥30;

Wherein V2 is the abbe number of the second lens under d-line, and V1 is the abbe number of the first lens under d-line. When the relation is satisfied, the Abbe numbers of the first lens and the second lens under d-line can be reasonably configured, so that chromatic aberration of the optical system can be corrected, and imaging quality of the optical system can be improved.

(n1+n2)/f≤1mm^-1;

Wherein n1 is the refractive index of the first lens, n2 is the refractive index of the second lens, and f is the effective focal length of the optical system. When the relation is satisfied, the refractive powers of the first lens and the second lens and the effective focal length of the optical system can be reasonably configured, so that the aberration of the optical system can be better corrected, the imaging quality of the optical system is improved, and meanwhile, the total length of the optical system is also favorably shortened, so that the miniaturization design is realized.

|R11/R14|≤3.0;

Wherein R11 is a radius of curvature of the object side surface of the sixth lens element at the optical axis, and R14 is a radius of curvature of the image side surface of the seventh lens element at the optical axis. When the positive refractive power of the sixth lens element increases the spherical aberration of the optical system and the above-mentioned relational expression is satisfied, the object-side surface of the sixth lens element and the image-side surface of the seventh lens element can be reasonably configured to better correct the spherical aberration generated by the sixth lens element, and meanwhile, light rays can be better converged on the imaging surface of the optical system, so as to further improve the imaging quality of the optical 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, and the image capturing module can be miniaturized by shortening the total system length of the optical system.

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, and the electronic equipment can be miniaturized by shortening the total system length of the optical system.

Drawings

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

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

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

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

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

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

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

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

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

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

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

FIG. 12 is a 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 invention will be readily understood, a more particular description of the invention 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 invention. The present invention 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 invention, whereby the invention is not limited to the specific embodiments disclosed below.

In the description of the present invention, 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 invention 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 invention.

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, mechanically connected, electrically connected, directly connected, indirectly connected through an intervening medium, or in communication between two elements or in an interaction relationship between two elements, unless otherwise explicitly specified. 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, 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 element L1 has positive refractive power, which contributes to shortening the overall system length of the optical system 100, and the object-side surface S1 of the first lens element L1 is convex at the paraxial region, so that the positive refractive power of the first lens element L1 can be further enhanced, and the optical system 100 can be made shorter in size along the optical axis direction, which is beneficial to the miniaturization design of the optical system 100. The second lens element L2 with negative refractive power has a convex object-side surface S3 and a concave image-side surface S4 at paraxial regions. The third lens element L3 and the fourth lens element L4 with refractive power have a convex object-side surface S5 of the third lens element L3 at a paraxial region thereof, and a convex image-side surface S8 of the fourth lens element L4 at a paraxial region thereof. The fifth lens element L5 with negative refractive power. The sixth lens element L6 with positive refractive power has a convex object-side surface S11 at a paraxial region. The seventh lens element L7 with negative refractive power has a concave image-side surface S14 at a paraxial region of the seventh lens element L7.

In addition, in some embodiments, the optical system 100 is provided with a stop STO, which may be disposed on the object side of the first lens L1. In some embodiments, the optical system 100 further includes an infrared filter L8 disposed on the image side of the seventh lens element L7, and the infrared filter L8 includes an object side surface S15 and an image side surface S16. Further, the optical system 100 further includes an image plane S17 located at the image side of the seventh lens L7, where the image plane S17 is an imaging plane of the optical system 100, and the incident light can be imaged on the image plane 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. It should be noted that the ir filter L8 may be an ir cut filter for filtering the interference light, so as to prevent the interference light from reaching the image surface S17 of the optical system 100 to affect the normal imaging.

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. Further, in some embodiments, the object side and the image side of at least one lens in the optical system 100 are aspheric.

In some embodiments, the materials of the lenses in the optical system 100 may be glass or plastic. The use of a plastic lens can reduce the weight and production cost of the optical system 100, and can be matched with the smaller size of the optical system to realize the light and small-sized design of the optical system. 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. Further, in some embodiments, at least two lenses of the optical system 100 are made of plastic materials with different optical characteristics, so as to better correct chromatic aberration 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, 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. Or, the first lens L1 does not have a cemented lens, but the distance between the lenses is relatively fixed, and at this time, 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 0.6+.TTL/(ImgH 2) ++.0.8, where TTL is the total system length of the optical system 100, i.e. the distance between the object side S1 of the first lens L1 and the imaging plane of the optical system 100 on the optical axis, and ImgH is half of the diagonal length of the effective pixel area of the optical system 100 on the imaging plane. In particular, TTL/(ImgH.times.2) may be 0.625, 0.631, 0.645, 0.658, 0.669, 0.672, 0.675, 0.684, 0.696 or 0.722. When the above conditional expression is satisfied, the system overall length of the optical system 100 and the diagonal length of the effective pixel region on the imaging plane can be reasonably configured, which is favorable for shortening the system overall length of the optical system 100, thereby satisfying the requirement of miniaturized design.

In some embodiments, the optical system 100 satisfies the conditional expression 38 FOV/2 FOV 46, where HFOV is the maximum field angle of the optical system 100 in the diagonal direction of the effective pixel area on the imaging surface. Specifically, the FOV/2 may be 39.5, 40.0, 40.2, 40.5, 41.3, 41.8, 42.5, 42.9, 43.7, or 44.5. When the above relation is satisfied, the optical system 100 has a large viewing angle characteristic, and can satisfy a large viewing angle shooting requirement.

In some embodiments, the optical system 100 satisfies the conditional expression that DL/TTL is 0.75. Ltoreq.DL≤1.1, where DL 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, and TTL is the total system length of the optical system 100. In particular, the DL/TTL can be 0.821, 0.835, 0.856, 0.867, 0.872, 0.893, 0.912, 0.925, 0.947, or 0.978. When the above relation is satisfied, the structure of the optical system 100 can be reasonably laid out, and the distance from the image side surface S14 of the seventh lens L7 to the imaging surface of the optical system 100 on the optical axis is increased while the miniaturization design requirement is satisfied, so that the layout of the module structure end is facilitated.

In some embodiments, the object side and the image side of each lens in the optical system 100 are aspheric, and the optical system 100 satisfies the conditional expression that TTL/f is 1.0-1.5, wherein TTL is the total system length of the optical system 100, and f is the effective focal length of the optical system 100. Specifically, TTL/f can be 1.160, 1.183, 1.199, 1.205, 1.263, 1.275, 1.292, 1.304, 1.325, or 1.348. When the above relation is satisfied, the total system length and the effective focal length of the optical system 100 can be reasonably configured, so that the structural layout of the optical system 100 is compact and reasonable, and the requirement of miniaturized design is further satisfied. The arrangement of the aspheric surface is also beneficial to balancing chromatic aberration, spherical aberration, distortion and other aberration of the optical system 100 under the condition of meeting the requirement of large-view shooting, so as to further improve the imaging quality of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression f23<0, where f23 is the combined focal length of the second lens L2 and the third lens L3. In particular, f23 may be-82.626, -79.325, -65, 257, -60.324, -52.396, -43.159, -40.024, -30.632, -16.745, or-8.156. When the above-described relational expression is satisfied, the combined focal length of the second lens element L2 and the third lens element L3 can be appropriately arranged, and the combined focal length can be matched with the positive refractive power of the first lens element L1, so that the aberration generated by the optical system 100 can be effectively balanced, and the light rays of the marginal field of view of the optical system 100 can be better converged on the imaging surface. In addition, the structural layout of the optical system 100 can be made more compact, which is advantageous for shortening the overall system length of the optical system 100 and realizing a miniaturized design.

In some embodiments, the optical system 100 satisfies the conditional expression 0≤R14/f≤1, where R14 is a radius of curvature of the image side S14 of the seventh lens L7 at the optical axis, and f is an effective focal length of the optical system 100. Specifically, R14/f may be 0.381, 0.398, 0.402, 0.439, 0.487, 0.524, 0.671, 0.853, 0.903, or 0.944. When the above relation is satisfied, the radius of curvature of the image side surface S14 of the seventh lens L7 at the optical axis and the effective focal length of the optical system 100 can be reasonably configured, so that the surface shape of the image side surface S14 of the seventh lens L7 is smoother, which is beneficial to suppressing the occurrence of curvature of field and distortion of the optical system 100, improving the imaging quality of the optical system 100, and reducing the molding difficulty of the seventh lens L7. In addition, it is also advantageous to control the overall system length of the optical system 100 so that the overall system length of the optical system 100 is not too long.

In some embodiments, the optical system 100 satisfies the conditional expression +|f6+|f7|+|12mm, where f6 is the effective focal length of the sixth lens L6 and f7 is the effective focal length of the seventh lens L7. Specifically, |f6|+|f7| can be 9.413, 9.546, 9.638, 9.763, 9.925, 10.058, 10.237, 10.564, 10.794, or 10.873. When the above relation is satisfied, the effective focal lengths of the sixth lens element L6 and the seventh lens element L7 can be reasonably configured to better balance the spherical aberration generated by each lens element on the object side of the sixth lens element L6, and meanwhile, the aberration of the field of view at the edge of the optical system 100 can be better corrected, so as to further improve the imaging quality of the optical system 100. In addition, the overall system length of the optical system 100 can be advantageously reduced, and a compact design can be realized.

In some embodiments, the optical system 100 satisfies the conditional expression |V2-V1|gtoreq.30, wherein V2 is the Abbe number of the second lens L2 at d-line (587.56 nm) and V1 is the Abbe number of the first lens L1 at d-line. Specifically, |V2-V1| can be 35.71, 35.85, 35.94, 36.01, 36.13, 36.24, 36.38, 36.45, 36.52, or 36.71. When the above relation is satisfied, the abbe numbers of the first lens L1 and the second lens L2 under the d-line can be reasonably configured, which is favorable for correcting the chromatic aberration of the optical system 100, and further improving the imaging quality of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression (n1+n2)/f≤1 mm ^-1, where n1 is the refractive index of the first lens L1, n2 is the refractive index of the second lens L2, and f is the effective focal length of the optical system 100. Specifically, (n1+n2)/f may be 0.579, 0.583, 0.594, 0.612, 0.628, 0.637, 0.645, 0.652, 0.663 or 0.689 in mm ^-1. When the above relation is satisfied, the refractive powers of the first lens element L1 and the second lens element L2 and the effective focal length of the optical system 100 can be reasonably configured to better correct the aberration of the optical system 100, improve the imaging quality of the optical system 100, and simultaneously facilitate shortening the overall system length of the optical system 100 to achieve a miniaturized design.

In some embodiments, the optical system 100 satisfies the conditional expression of R11/R14. Ltoreq.3.0, wherein R11 is a radius of curvature of the object-side surface S11 of the sixth lens element L6 at the optical axis, and R14 is a radius of curvature of the image-side surface S14 of the seventh lens element L7 at the optical axis. Specifically, |R11/R14| may be 0.390, 0.528, 0.739, 0.927, 1.374, 1.785, 1.903, 2.055, 2.281, or 2.349. When the positive refractive power of the sixth lens element L6 increases the spherical aberration of the optical system 100 and satisfies the above-mentioned relationship, the object-side surface S11 of the sixth lens element L6 and the image-side surface S14 of the seventh lens element L7 can be reasonably arranged to better correct the aberration generated by the sixth lens element L6, and meanwhile, the light beam can be better converged on the imaging surface of the optical system 100, so as to further improve the imaging quality of the optical system 100.

From the above description of the embodiments, more particular embodiments and figures are set forth below in detail.

First embodiment

Referring to fig. 1 and 2, fig. 1 is a schematic 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 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 the paraxial region and convex at the circumferential region;

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

the image-side surface S4 of the second lens element L2 has a concave surface at the paraxial region and a concave surface at the circumferential 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 the paraxial region and convex at the circumferential region;

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

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

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

The image-side surface S10 of the fifth lens element L5 is convex at the paraxial region and convex at the circumferential region;

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

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

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

the image-side surface S14 of the seventh lens element L7 has a concave surface at the paraxial region and a convex surface at the circumferential 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 it is described that one surface of the lens is convex at the paraxial side (the center region of the side 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 the optical axis and also convex at the circumference, the shape of the surface from the center (optical axis) to the edge may be purely convex, or the shape may be a transition from a convex shape at 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 TTL/(imgh×2) =0.636, where TTL is the total system length of the optical system 100 and ImgH is half of the diagonal length of the effective pixel area of the optical system 100 on the imaging plane. When the above conditional expression is satisfied, the system overall length of the optical system 100 and the diagonal length of the effective pixel region on the imaging plane can be reasonably configured, which is favorable for shortening the system overall length of the optical system 100, thereby satisfying the requirement of miniaturized design.

The optical system 100 satisfies the condition that FOV/2=42.5°, where FOV is the maximum field angle of the optical system 100 in the diagonal direction of the effective pixel area on the imaging plane. When the above relation is satisfied, the optical system 100 has a large viewing angle characteristic, and can satisfy a large viewing angle shooting requirement.

The optical system 100 satisfies the conditional expression DL/ttl=0.829, wherein DL 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, and TTL is the total system length of the optical system 100. When the above relation is satisfied, the structure of the optical system 100 can be reasonably laid out, and the distance from the image side surface S14 of the seventh lens L7 to the imaging surface of the optical system 100 on the optical axis is increased while the miniaturization design requirement is satisfied, so that the layout of the module structure end is facilitated.

The object side surface and the image side surface of each lens in the optical system 100 are aspheric, and the optical system 100 satisfies the conditional expression of TTL/f=1.180, where TTL is the total system length of the optical system 100, and f is the effective focal length of the optical system 100. When the above relation is satisfied, the total system length and the effective focal length of the optical system 100 can be reasonably configured, so that the structural layout of the optical system 100 is compact and reasonable, and the requirement of miniaturized design is further satisfied. The arrangement of the aspheric surface is also beneficial to balancing chromatic aberration, spherical aberration, distortion and other aberration of the optical system 100 under the condition of meeting the requirement of large-view shooting, so as to further improve the imaging quality of the optical system 100.

The optical system 100 satisfies a conditional expression of f23= -82.616, where f23 is a combined focal length of the second lens L2 and the third lens L3. When the above-described relational expression is satisfied, the combined focal length of the second lens element L2 and the third lens element L3 can be appropriately arranged, and the combined focal length can be matched with the positive refractive power of the first lens element L1, so that the aberration generated by the optical system 100 can be effectively balanced, and the light rays of the marginal field of view of the optical system 100 can be better converged on the imaging surface. In addition, the structural layout of the optical system 100 can be made more compact, which is advantageous for shortening the overall system length of the optical system 100 and realizing a miniaturized design.

The optical system 100 satisfies the conditional expression that R14/f=0.389, where R14 is a radius of curvature of the image side surface S14 of the seventh lens L7 at the optical axis, and f is an effective focal length of the optical system 100. When the above relation is satisfied, the radius of curvature of the image side surface S14 of the seventh lens L7 at the optical axis and the effective focal length of the optical system 100 can be reasonably configured, so that the surface shape of the image side surface S14 of the seventh lens L7 is smoother, which is beneficial to suppressing the occurrence of curvature of field and distortion of the optical system 100, improving the imaging quality of the optical system 100, and reducing the molding difficulty of the seventh lens L7. In addition, it is also advantageous to control the overall system length of the optical system 100 so that the overall system length of the optical system 100 is not too long.

The optical system 100 satisfies the conditional expression of |f6|+|f7|= 9.742mm, where f6 is the effective focal length of the sixth lens L6 and f7 is the effective focal length of the seventh lens L7. When the above relation is satisfied, the effective focal lengths of the sixth lens element L6 and the seventh lens element L7 can be reasonably configured to better balance the spherical aberration generated by each lens element on the object side of the sixth lens element L6, and meanwhile, the aberration of the field of view at the edge of the optical system 100 can be better corrected, so as to further improve the imaging quality of the optical system 100. In addition, the overall system length of the optical system 100 can be advantageously reduced, and a compact design can be realized.

The optical system 100 satisfies the conditional expression of V2-V1 = 36.710, where V2 is the abbe number of the second lens L2 under the d-line and V1 is the abbe number of the first lens L1 under the d-line. When the above relation is satisfied, the abbe numbers of the first lens L1 and the second lens L2 under the d-line can be reasonably configured, which is favorable for correcting the chromatic aberration of the optical system 100, and further improving the imaging quality of the optical system 100.

The optical system 100 satisfies the conditional expression (n1+n2)/f=0.643 mm ^-1, where n1 is the refractive index of the first lens L1, n2 is the refractive index of the second lens L2, and f is the effective focal length of the optical system 100. When the above relation is satisfied, the refractive powers of the first lens element L1 and the second lens element L2 and the effective focal length of the optical system 100 can be reasonably configured to better correct the aberration of the optical system 100, improve the imaging quality of the optical system 100, and simultaneously facilitate shortening the overall system length of the optical system 100 to achieve a miniaturized design.

The optical system 100 satisfies the conditional expression of R11/R14 = 2.306, wherein R11 is a radius of curvature of the object side surface S11 of the sixth lens element L6 at the optical axis, and R14 is a radius of curvature of the image side surface S14 of the seventh lens element L7 at the optical axis. When the positive refractive power of the sixth lens element L6 increases the spherical aberration of the optical system 100 and the above-mentioned relationship is satisfied, the object-side surface S11 of the sixth lens element L6 and the image-side surface S14 of the seventh lens element L7 can be reasonably arranged to better correct the spherical aberration generated by the sixth lens element L6, and meanwhile, the light beam can be better converged on the imaging surface of the optical system 100, so as to further improve the imaging quality of the optical system 100.

In addition, various parameters of the optical system 100 are given in table 1. The image plane S17 in table 1 can be understood as the imaging plane of the optical system 100. The elements from the object plane (not shown) to the image plane S17 are 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 number 1 and the surface number 2 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 object side surface of the lens element on the optical axis.

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 remains unchanged.

In the first embodiment, the effective focal length f=5.0 mm, the f-number fno=1.9, the maximum field angle fov=85°, the total system length ttl=5.9 mm, the half of the diagonal length imgh=4.64 mm of the effective pixel area on the imaging plane, the maximum imaging circle diameter mic=9.54 mm on the imaging plane, and the distance dl= 4.894mm on the optical axis between the object side surface S1 of the first lens L1 and the image side surface S14 of the seventh lens L7.

The focal length of each lens was a value at wavelength=555 nm, and the refractive index and abbe number of each lens were values at d-line (587.56 nm), and the same applies to other examples.

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 1-14 represent the image side or 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

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

f34	-266.146	f56	6.196
				f45	-13.472	f67	-41.793

wherein f23 is a combined focal length of the second lens L2 and the third lens L3, f34 is a combined focal length of the third lens L3 and the fourth lens L4, f45 is a combined focal length of the fourth lens L4 and the fifth lens L5, f56 is a combined focal length of the fifth lens L5 and the sixth lens L6, and f67 is a combined focal length of the sixth lens L6 and the seventh lens L7, which are the same as the other embodiments.

Second embodiment

Referring to fig. 3 and 4, fig. 3 is a schematic 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 positive refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with negative refractive power, a sixth lens element L6 with positive refractive power, and a seventh lens element L7 with negative refractive power. Fig. 4 is a graph showing, in order from left to right, spherical aberration, astigmatism and distortion of the optical system 100 according to the second embodiment.

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

TTL/(ImgH*2)	0.625	(n1+n2)/f	0.643
				HFOV	42.35	\|R11/R14\|	2.170867
DL/TTL	0.82137931	f23	-26.711
				TTL/f	1.16	f34	-162.033
R14/f	0.4005356	f45	-17.034
				\|f6\|+\|f7\|	9.709007	f56	6.044
\|V2-V1\|	36.71	f67	-71.679

Third embodiment

Referring to fig. 5 and 6, fig. 5 is a schematic 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 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. 6 is a graph showing, in order from left to right, spherical aberration, astigmatism and distortion of the optical system 100 according to the third embodiment.

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

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

TTL/(ImgH*2)	0.63362069	(n1+n2)/f	0.645582
				HFOV	42.5	\|R11/R14\|	2.348706
DL/TTL	0.977911647	f23	-57.299
				TTL/f	1.180722892	f34	-75.377
R14/f	0.381280594	f45	-12.960
				\|f6\|+\|f7\|	9.412561	f56	5.948
\|V2-V1\|	36.71	f67	-48.246

Fourth embodiment

Referring to fig. 7 and 8, fig. 7 is a schematic 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 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. 8 is a graph showing, in order from left to right, spherical aberration, astigmatism and distortion of the optical system 100 in the fourth embodiment.

The image-side surface S2 of the first lens element L1 has a concave surface at the paraxial region and a concave surface at the circumferential region;

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

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

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

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

TTL/(ImgH*2)	0.721982759	(n1+n2)/f	0.579385
				HFOV	39.5	\|R11/R14\|	0.426198
DL/TTL	0.849253731	f23	-8.259
				TTL/f	1.211573237	f34	23.738
R14/f	0.836544491	f45	26.773
				\|f6\|+\|f7\|	10.872545	f56	8.827
\|V2-V1\|	35.71	f67	170.255

Fifth embodiment

Referring to fig. 9 and 10, fig. 9 is a schematic 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 negative refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with negative refractive power, a sixth lens element L6 with positive refractive power, and a seventh lens element L7 with negative refractive power. Fig. 10 is a graph showing, in order from left to right, spherical aberration, astigmatism and distortion of the optical system 100 in the fifth embodiment.

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

TTL/(ImgH*2)	0.700431034	(n1+n2)/f	0.62947
				HFOV	42	\|R11/R14\|	0.438325
DL/TTL	0.838461538	f23	-8.156
				TTL/f	1.277013752	f34	20.265
R14/f	0.831114694	f45	22.027
				\|f6\|+\|f7\|	10.217879	f56	7.201
\|V2-V1\|	35.71	f67	30.077

Sixth embodiment

Referring to fig. 11 and 12, fig. 11 is a schematic 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 negative refractive power, a sixth lens element L6 with positive refractive power, and a seventh lens element L7 with negative refractive power. Fig. 12 is a graph showing, in order from left to right, spherical aberration, astigmatism and distortion of the optical system 100 in the sixth embodiment.

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

TTL/(ImgH*2)	0.675646552	(n1+n2)/f	0.689032
				HFOV	44.5	\|R11/R14\|	0.390214
DL/TTL	0.832535885	f23	-8.387
				TTL/f	1.348387097	f34	19.828
R14/f	0.944471249	f45	20.518
				\|f6\|+\|f7\|	10.058023	f56	6.310
\|V2-V1\|	35.71	f67	16.718

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 can be regarded as the image surface S17 of the optical system 100. The image capturing module 200 may further be provided with an infrared filter L8, where the infrared filter L8 is disposed between the image side surface S14 and the image plane 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 used in the image capturing module 200, and the overall system length of the optical system 100 is reduced, thereby enabling the image capturing module 200 to be miniaturized.

Referring to fig. 13 and 14, 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 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. The image capturing module 200 is used in the electronic apparatus 300, and the overall system length of the optical system 100 is reduced, thereby enabling the electronic apparatus 300 to be designed to be miniaturized.

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 it comprises seven lenses having refractive power, arranged sequentially from the object side to the image side:

A first lens with positive refractive power, wherein the object side of the first lens is convex near the axis and the image side is concave near the axis;

A second lens with negative refractive power, wherein the object side of the second lens is convex at the paraxial side and the image side is concave at the paraxial side;

A third lens with refractive power, wherein the object-side surface of the third lens is convex at the paraxial position;

A fourth lens with refractive power, wherein the image-side surface of the fourth lens is convex at the paraxial position;

The fifth lens has negative refractive power;

A sixth lens having positive refractive power, wherein the object-side surface of the sixth lens is convex at the paraxial position;

A seventh lens with negative refractive power, wherein the image-side surface of the seventh lens is concave at the paraxial position;

And the optical system satisfies the following condition:

0.625≤TTL/(ImgH) 2) ≤0.675646552,

1.16≤TTL/f≤1.348387097

0.381≤R14/f≤1,

42.35°≤FOV/2≤44.5°

0.390≤|R11/R14|≤2.349,

f23 < 0;

Wherein, TTL is the total length of the optical system, ImgH is half the diagonal length of the effective pixel area of the optical system on the imaging plane, f is the effective focal length of the optical system, R14 is the radius of curvature of the image side of the seventh lens at the optical axis, FOV is the maximum field of view of the optical system in the diagonal direction of the effective pixel area on the imaging plane, R11 is the radius of curvature of the object side of the sixth lens at the optical axis, R14 is the radius of curvature of the image side of the seventh lens at the optical axis, and f23 is the combined focal length of the second lens and the third lens.

2. The optical system according to claim 1, characterized in that it satisfies the following condition:

0.82137931≤DL/TTL≤0.977911647;

Wherein, DL is the distance on the optical axis from the object side of the first lens to the image side of the seventh lens, and TTL is the total length of the optical system.

3. The optical system according to claim 1, characterized in that it satisfies the following condition:

9.412561mm≤|f6|+|f7|≤12mm;

Wherein, f6 is the effective focal length of the sixth lens, and f7 is the effective focal length of the seventh lens.

4. The optical system according to claim 1, characterized in that it satisfies the following condition:

|V2-V1|≥30;

Wherein, V2 is the Abbe number of the second lens under the d-line, and V1 is the Abbe number of the first lens under the d-line.

5. The optical system according to claim 1, characterized in that it satisfies the following condition:

(n1+n2)/f≤1mm ^-1 ;

Wherein, n1 is the refractive index of the first lens, n2 is the refractive index of the second lens, and f is the effective focal length of the optical system.

6. An image-capturing module, characterized in that it includes a photosensitive element and an optical system as described in any one of claims 1-5, wherein the photosensitive element is disposed on the image side of the optical system.

7. An electronic device, characterized in that it comprises a housing and an image-capturing module as described in claim 6, the image-capturing module being disposed in the housing.