CN111812804A

CN111812804A - Optical system, image capturing module and electronic equipment

Info

Publication number: CN111812804A
Application number: CN202010715977.7A
Authority: CN
Inventors: 刘彬彬; 李明; 邹海荣
Original assignee: OFilm Tech Co Ltd
Current assignee: Nanchang OFilm Precision Optical Products Co Ltd; OFilm Group Co Ltd
Priority date: 2020-07-23
Filing date: 2020-07-23
Publication date: 2020-10-23

Abstract

The invention relates to an optical system, an image capturing module and an electronic device. The optical system includes in order from an object side to an image side: the first lens element with positive refractive power has a convex object-side surface and a concave image-side surface; a second lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a third lens element with refractive power having a convex object-side surface at paraxial region; a fourth lens element with refractive power having a convex image-side surface at 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 paraxial region; a seventh lens element with negative refractive power having a concave image-side surface at the paraxial region; the optical system satisfies the following conditional expression: TTL/(ImgH 2) is more than or equal to 0.6 and less than or equal to 0.8. When the above conditional expressions are satisfied, the total length of the optical system can be shortened to satisfy the requirement of the miniaturization design.

Description

Optical system, image capturing module and electronic equipment

Technical Field

The present invention relates to the field of camera shooting, 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 higher and higher requirements on the electronic devices, and the electronic devices are required to be equipped with an optical system to have a camera shooting function, and also are expected to be designed to be miniaturized to have a small size and be convenient to carry and use. However, the size of the conventional optical system is usually large, and it 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 desirable to provide an optical system, an image capturing module and an electronic device, which are capable of solving the problem that the conventional optical system is difficult to meet the requirement of the miniaturization design of the electronic device.

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 and a concave image-side surface;

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

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

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

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

and the optical system satisfies the following conditional expression:

0.6≤TTL/(ImgH*2)≤0.8；

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

In the optical system, the first lens element has positive refractive power, which is beneficial to shortening the total 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 size of the optical system in the optical axis direction is shortened, and the optical system is beneficial to miniaturization design. When the conditional expressions are satisfied, the system total length of the optical system and the diagonal length of the effective pixel area on the imaging surface can be reasonably configured, which is beneficial to shortening the system total length of the optical system and further satisfies the requirement of miniaturization 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 plane. When the relational expression is satisfied, the optical system has a large-view angle characteristic and can satisfy the requirement of large-view 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 system 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 miniaturization design is further satisfied. The aspheric surface is favorable for balancing aberration such as chromatic aberration, spherical aberration and distortion of the optical system under the condition of meeting the requirement of large-view-angle shooting, and further the imaging quality of the optical system is improved.

0.75≤DL/TTL≤1.1；

DL is a distance on an optical axis from an object-side surface of the first lens element to an image-side surface of the seventh lens element, and TTL is a total system length of the optical system, i.e., a distance on the optical axis from the object-side surface of the first lens element to an image plane of the optical system. When satisfying above-mentioned relational expression, can be right optical system's structure carries out reasonable layout, when satisfying miniaturized design requirement, increases the image side face of seventh lens extremely optical system's imaging surface is in the epaxial distance of light, and then is favorable to the overall arrangement of module structure end.

f23＜0；

wherein f23 is the combined focal length of the second lens and the third lens. When the above relational expression is satisfied, the combined focal length of the second lens element and the third lens element can be reasonably configured, and the combined focal length is matched with the positive refractive power of the first lens element, so that the aberration generated by the optical system can be effectively balanced, and meanwhile, the light rays of the marginal field of view of the optical system can be better converged on an imaging surface. In addition, the structural layout of the optical system can be more compact, which is beneficial to shortening the total length of the optical system and realizing miniaturization design.

0≤R14/f≤1；

wherein R14 is a radius of curvature of an image-side surface of the seventh lens at an optical axis, and f is an effective focal length of the optical system. When the relation is satisfied, the curvature radius 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 type of the image side surface of the seventh lens is more gentle, the generation of field curvature and distortion of the optical system is favorably inhibited, the imaging quality of the optical system is improved, and the forming difficulty of the seventh lens can be reduced. In addition, the control of the total system length of the optical system is facilitated, so that the total system length of the optical system is not too long.

|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. When the above relational expression is satisfied, the effective focal lengths of the sixth lens and the seventh lens can be reasonably configured, so that the spherical aberration generated by each lens at the object side of the sixth lens can be better balanced, meanwhile, the aberration of the marginal field of view of the optical system can be better corrected, and the imaging quality of the optical system is further improved. In addition, the system total length of the optical system can be shortened, and the miniaturization design can be 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 the d-line can be reasonably configured, which is beneficial to correcting chromatic aberration of the optical system, and further improves the imaging quality of the optical system.

(n1+n2)/f≤1mm^-1；

wherein n1 is a refractive index of the first lens, n2 is a refractive index of the second lens, and f is an effective focal length of the optical system. When the above relational expression is satisfied, the refractive powers of the first lens element and the second lens element 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 can be improved, and the total length of the optical system can be shortened, thereby realizing the miniaturization design.

|R11/R14|≤3.0；

wherein R11 is a radius of curvature of an object-side surface of the sixth lens element at an optical axis, and R14 is a radius of curvature of an image-side surface of the seventh lens element at the optical axis. The positive refractive power of the sixth lens element increases the spherical aberration of the optical system, and when 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 arranged, so as to better correct the spherical aberration generated by the sixth lens element, and simultaneously, the light can better converge on the imaging surface of the optical system, thereby improving the imaging quality of the optical system.

An image capturing module includes a photosensitive element and the optical system of any of the above embodiments, wherein the photosensitive element is disposed at an image side of the optical system. The optical system is adopted in the image capturing module, and the overall length of the optical system is shortened, so that the image capturing module can be designed in a miniaturized manner.

An electronic device comprises a shell and the image capturing module, wherein the image capturing module is arranged on the shell. The image capturing module is adopted in the electronic equipment, and the electronic equipment can be designed in a miniaturized mode by shortening the total length of the optical system.

Drawings

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

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

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

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

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

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

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

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

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

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

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

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

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

fig. 14 is a schematic diagram of an electronic device in an embodiment of the present application.

Detailed Description

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

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

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

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

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

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

In some embodiments of the present disclosure, referring to fig. 1, 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 L1 includes an object-side surface S1 and an image-side surface S2, the second lens L2 includes an object-side surface S3 and an image-side surface S4, the third lens L3 includes an object-side surface S5 and an image-side surface S6, the fourth lens L4 includes an object-side surface S7 and an image-side surface S8, the fifth lens L5 includes an object-side surface S9 and an image-side surface S10, the sixth lens L6 includes an object-side surface S11 and an image-side surface S12, and the seventh lens L7 includes an object-side surface S13 and an image-side surface S14.

The first lens element L1 with positive refractive power helps to shorten the total 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, the size of the optical system 100 in the optical axis direction can be further shortened, and the optical system 100 can be miniaturized. 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 of the second lens element L2. The third lens element L3 and the fourth lens element L4 have refractive power, and the object-side surface S5 of the third lens element L3 is convex paraxially, and the image-side surface S8 of the fourth lens element L4 is convex paraxially. The fifth lens element L5 has negative refractive power. The sixth lens element L6 with positive refractive power has a convex object-side surface S11 at the paraxial region of the sixth lens element L6. The seventh lens element L7 with negative refractive power has a concave image-side surface S14 at the 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 L7, and the infrared filter L8 includes an object-side surface S15 and an image-side surface S16. Furthermore, the optical system 100 further includes an image plane S17 located on the image side of the seventh lens L7, the image plane S17 is an imaging plane of the optical system 100, and incident light is 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 and can be imaged on the image plane S17. It should be noted that the infrared filter L8 may be an infrared cut filter, and is used for filtering the interference light and preventing the interference light from reaching the image plane S17 of the optical system 100 to affect the normal imaging.

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

In some embodiments, each lens in the optical system 100 may be made of glass or plastic. The lens made of plastic material can reduce the weight of the optical system 100 and the production cost, and the small size of the optical system is matched to realize the light and small design of the optical system. The glass lens provides the optical system 100 with excellent optical performance and high temperature resistance. It should be noted that the material of each lens in the optical system 100 may be any combination of glass and plastic, and is not necessarily both glass and plastic. Further, in some embodiments, at least two of the 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 is to be noted that the first lens L1 does not mean that there is only one lens, and in some embodiments, there may be two or more lenses in the first lens L1, and the two or more lenses can form a cemented lens, and a surface of the cemented lens closest to the object side can be regarded as the object side surface S1, and a surface of the cemented lens closest to the image side can be regarded as the image side surface S2. Alternatively, although no cemented lens is formed between the lenses of the first lens L1, the distance between the lenses is relatively fixed, and in this case, the object-side surface of the lens closest to the object side is the object-side surface S1, and the image-side surface of the lens closest to the image side is the image-side surface S2. In addition, the number of lenses in the second lens L2, the third lens L3, the fourth lens L4, 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 a cemented lens may be formed between any two adjacent lenses, or a non-cemented lens may be used.

Further, in some embodiments, the optical system 100 satisfies the conditional expression: TTL/(ImgH 2) is more than or equal to 0.6 and less than or equal to 0.8; wherein, TTL is the total system length of the optical system 100, i.e., the distance from the object-side surface S1 of the first lens element L1 to 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. Specifically, TTL/(ImgH × 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 expressions are satisfied, the system total 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 beneficial to shortening the system total length of the optical system 100, and further satisfies the requirement of miniaturization design.

In some embodiments, the optical system 100 satisfies the conditional expression: FOV/2 is more than or equal to 38 degrees and less than or equal to 46 degrees; the HFOV is a maximum angle of view of the optical system 100 in a diagonal direction of the effective pixel region on the imaging plane. Specifically, 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 relational expression 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: DL/TTL is more than or equal to 0.75 and less than or equal to 1.1; DL is a distance on the optical axis from the object-side surface S1 of the first lens element L1 to the image-side surface S14 of the seventh lens element L7, and TTL is a total system length of the optical system 100. Specifically, DL/TTL may be: 0.821, 0.835, 0.856, 0.867, 0.872, 0.893, 0.912, 0.925, 0.947, or 0.978. When satisfying above-mentioned relational expression, can carry out reasonable overall arrangement to optical system 100 ' S structure, when satisfying miniaturized design requirement, increase seventh lens L7 ' S image side S14 to optical system 100 ' S the distance of imaging surface on the optical axis, and then be favorable to the overall arrangement of module structure end.

In some embodiments, 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 following conditional expression: TTL/f is more than or equal to 1.0 and less than or equal to 1.5; where 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 may 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 miniaturization design is further satisfied. The aspheric surface is favorable for balancing aberration such as chromatic aberration, spherical aberration and distortion of the optical system 100 under the condition of meeting the requirement of large-view-angle shooting, and further the imaging quality of the optical system 100 is improved.

In some embodiments, the optical system 100 satisfies the conditional expression: f23 < 0; wherein f23 is the combined focal length of the second lens L2 and the third lens L3. Specifically, 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 relation is satisfied, the combined focal length of the second lens element L2 and the third lens element L3 can be configured reasonably, and the combined focal length can be matched with the positive refractive power of the first lens element L1, so that the aberrations generated by the optical system 100 can be effectively balanced, and simultaneously, the light rays of the marginal field of view of the optical system 100 can be better converged on the imaging plane. In addition, the layout of the optical system 100 can be made more compact, which is advantageous for shortening the overall length of the optical system 100 and realizing a compact design.

In some embodiments, the optical system 100 satisfies the conditional expression: r14/f is more than or equal to 0 and less than or equal to 1; where R14 is a curvature radius 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. 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 relational expression is satisfied, the curvature radius 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 arranged, so that the surface shape of the image-side surface S14 of the seventh lens L7 is more gentle, 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 difficulty in molding the seventh lens L7. In addition, it is also advantageous to control the total system length of the optical system 100 so that the total system length of the optical system 100 is not excessively long.

In some embodiments, the optical system 100 satisfies the conditional expression: the | f6| + | f7| is less than or equal to 12 mm; where f6 is an effective focal length of the sixth lens L6, and f7 is an effective focal length of the seventh lens L7. Specifically, | f6| + | f7| may 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 L6 and the seventh lens L7 can be reasonably configured, so as to better balance the spherical aberration generated by each lens on the object side of the sixth lens L6, and better correct the aberration of the peripheral field of view of the optical system 100, thereby improving the imaging quality of the optical system 100. In addition, it is also advantageous to shorten the total length of the optical system 100 and to realize a compact design.

In some embodiments, the optical system 100 satisfies the conditional expression: the | V2-V1| ≧ 30; wherein V2 is the abbe number of the second lens L2 under d-line (587.56nm), and V1 is the abbe number of the first lens L1 under d-line. Specifically, | V2-V1| may 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 relational expression is satisfied, abbe numbers of the first lens L1 and the second lens L2 under the d-line can be reasonably configured, which is beneficial to correcting chromatic aberration of the optical system 100, and further improves imaging quality of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: (n1+ n2)/f is less than or equal to 1mm^-1(ii) a 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, the numerical units being mm^-1. When the above-mentioned relational expression 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, so as to better correct the aberration of the optical system 100, improve the imaging quality of the optical system 100, and simultaneously facilitate shortening the total length of the optical system 100, thereby achieving a miniaturized design.

In some embodiments, the optical system 100 satisfies the conditional expression: the ratio of R11 to R14 is less than or equal to 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. The positive refractive power of the sixth lens element L6 increases the spherical aberration of the optical system 100, and when the above-mentioned relational expression 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, so as to better correct the aberration generated by the sixth lens element L6, and enable the light rays to better converge on the image plane of the optical system 100, thereby improving the imaging quality of the optical system 100.

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

First embodiment

Referring to fig. 1 and fig. 2, fig. 1 is a schematic diagram of the optical system 100 in the first embodiment, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with 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 the spherical aberration, astigmatism and distortion of the optical system 100 in the first embodiment, in which the reference wavelength of the astigmatism graph and the distortion graph is 555nm, from left to right, and the other embodiments are the same.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The object-side surface and the image-side surface of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are aspheric.

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

The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are all made of plastic.

Further, the optical system 100 satisfies the conditional expression: TTL/(ImgH × 2) ═ 0.636; wherein, TTL is the total system length of the optical system 100, and ImgH is half the diagonal length of the effective pixel area of the optical system 100 on the imaging plane. When the above conditional expressions are satisfied, the system total 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 beneficial to shortening the system total length of the optical system 100, and further satisfies the requirement of miniaturization design.

The optical system 100 satisfies the conditional expression: FOV/2-42.5 °; the 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 relational expression 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; DL is a distance on the optical axis from the object-side surface S1 of the first lens element L1 to the image-side surface S14 of the seventh lens element L7, and TTL is a total system length of the optical system 100. When satisfying above-mentioned relational expression, can carry out reasonable overall arrangement to optical system 100 ' S structure, when satisfying miniaturized design requirement, increase seventh lens L7 ' S image side S14 to optical system 100 ' S the distance of imaging surface on the optical axis, and then be favorable to the overall arrangement of module structure end.

The object-side surface and the image-side surface of each lens in the optical system 100 are aspheric surfaces, and the optical system 100 satisfies the conditional expression: TTL/f is 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 miniaturization design is further satisfied. The aspheric surface is favorable for balancing aberration such as chromatic aberration, spherical aberration and distortion of the optical system 100 under the condition of meeting the requirement of large-view-angle shooting, and further the imaging quality of the optical system 100 is improved.

The optical system 100 satisfies the conditional expression: f23 ═ 82.616; wherein f23 is the combined focal length of the second lens L2 and the third lens L3. When the above relation is satisfied, the combined focal length of the second lens element L2 and the third lens element L3 can be configured reasonably, and the combined focal length can be matched with the positive refractive power of the first lens element L1, so that the aberrations generated by the optical system 100 can be effectively balanced, and simultaneously, the light rays of the marginal field of view of the optical system 100 can be better converged on the imaging plane. In addition, the layout of the optical system 100 can be made more compact, which is advantageous for shortening the overall length of the optical system 100 and realizing a compact design.

The optical system 100 satisfies the conditional expression: r14/f is 0.389; where R14 is a curvature radius 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 relational expression is satisfied, the curvature radius 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 arranged, so that the surface shape of the image-side surface S14 of the seventh lens L7 is more gentle, 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 difficulty in molding the seventh lens L7. In addition, it is also advantageous to control the total system length of the optical system 100 so that the total system length of the optical system 100 is not excessively long.

The optical system 100 satisfies the conditional expression: l f6| + | f7| ═ 9.742 mm; where f6 is an effective focal length of the sixth lens L6, and f7 is an effective focal length of the seventh lens L7. When the above relation is satisfied, the effective focal lengths of the sixth lens L6 and the seventh lens L7 can be reasonably configured, so as to better balance the spherical aberration generated by each lens on the object side of the sixth lens L6, and better correct the aberration of the peripheral field of view of the optical system 100, thereby improving the imaging quality of the optical system 100. In addition, it is also advantageous to shorten the total length of the optical system 100 and to realize a compact design.

The optical system 100 satisfies the conditional expression: 36.710, | V2-V1 |; wherein V2 is the abbe number of the second lens L2 under d-line, and V1 is the abbe number of the first lens L1 under d-line. When the above relational expression is satisfied, abbe numbers of the first lens L1 and the second lens L2 under the d-line can be reasonably configured, which is beneficial to correcting chromatic aberration of the optical system 100, and further improves imaging quality of the optical system 100.

The optical system 100 satisfies the conditional expression: (n1+ n2)/f 0.643mm^-1(ii) a Wherein n1 is refraction of the first lens L1The refractive index 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-mentioned relational expression 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, so as to better correct the aberration of the optical system 100, improve the imaging quality of the optical system 100, and simultaneously facilitate shortening the total length of the optical system 100, thereby achieving a miniaturized design.

The optical system 100 satisfies the conditional expression: 2.306, | R11/R14 |; 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. The positive refractive power of the sixth lens element L6 increases the spherical aberration of the optical system 100, and when the above-mentioned relational expression 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, so as to better correct the spherical aberration generated by the sixth lens element L6, and enable the light rays to better converge on the image plane of the optical system 100, thereby improving the image quality of the optical system 100.

In addition, the parameters of the optical system 100 are given in table 1. Among them, the image plane S17 in table 1 may be understood as an imaging plane of the optical system 100. The elements from the object plane (not shown) to the image plane S17 are sequentially arranged in the order of the elements from top to bottom in table 1. The Y radius in table 1 is the radius of curvature of the object-side surface or the image-side surface of the corresponding surface number at the optical axis. Surface number 1 and surface number 2 are the object-side surface S1 and the image-side surface S2 of the first lens L1, respectively, that is, in the same lens, 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. The first numerical value in the "thickness" parameter column of the first lens element L1 is the axial thickness of the lens element, and the second numerical value is the axial distance from the image-side surface of the lens element to the object-side surface of the following lens element in the image-side direction.

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 of the seventh lens L7 to the image surface S17 is kept constant at this time.

In the first embodiment, the effective focal length f of the optical system 100 is 5.0mm, the f-number FNO is 1.9, the maximum field angle FOV is 85 °, and the total system length TTL is 5.9 mm; the half ImgH of the diagonal length of the effective pixel area on the imaging plane of the system is 4.64mm, the maximum imaging circle diameter MIC of the system on the imaging plane is 9.54mm, and the distance DL between the object-side surface S1 of the first lens L1 and the image-side surface S14 of the seventh lens L7 on the optical axis is 4.894 mm.

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

TABLE 1

Further, aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are given by table 2. In which the surface numbers 1-14 represent image side surfaces or object side surfaces S1-S14, respectively. And K-a20 from top to bottom respectively indicate the types of aspheric coefficients, where K indicates a conic coefficient, a4 indicates a quartic aspheric coefficient, a6 indicates a sextic aspheric coefficient, A8 indicates an octal aspheric coefficient, and so on. In addition, the aspherical surface coefficient formula is as follows:

z is the distance from a corresponding point on the aspheric surface to a plane tangent to the surface vertex, r is the distance from the corresponding point on the aspheric surface to the optical axis, c is the curvature of the aspheric surface vertex, k is a conical coefficient, and Ai is a coefficient corresponding to the ith high-order term in the aspheric surface type formula.

TABLE 2

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

f34	-266.146	f56	6.196
				f45	-13.472	f67	-41.793

where 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 is the same as that in the other embodiments.

Second embodiment

Referring to fig. 3 and 4, fig. 3 is a schematic diagram of the optical system 100 in the second embodiment, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with 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 of spherical aberration, astigmatism and distortion of the optical system 100 in the second embodiment, from left to right.

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

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

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

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

TABLE 3

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

TABLE 4

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 the optical system 100 in the third embodiment, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with 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 of spherical aberration, astigmatism and distortion of the optical system 100 in the third embodiment, from left to right.

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

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

TABLE 5

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

TABLE 6

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 the optical system 100 in the fourth embodiment, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with 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 the spherical aberration, astigmatism and distortion of the optical system 100 in the fourth embodiment in order from left to right.

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

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

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

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

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

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

TABLE 7

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

TABLE 8

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 the optical system 100 in the fifth embodiment, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with 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 the 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 definitions of the parameters can be obtained from the first embodiment, which is not described herein.

TABLE 9

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

Watch 10

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 the optical system 100 in the sixth embodiment, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with 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 the spherical aberration, astigmatism and distortion of the optical system 100 in the sixth embodiment in order from left to right.

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

TABLE 11

Further, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are given in table 12, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated 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 light-sensing surface of the light-sensing element 210 may be regarded as the image surface S17 of the optical system 100. The image capturing module 200 may further include an infrared filter L8, and the infrared filter L8 is disposed between the image side surface S14 and the image surface S17 of the seventh lens element L7. Specifically, the photosensitive element 210 may be a Charge Coupled Device (CCD) or a Complementary Metal-Oxide Semiconductor (CMOS) Device. The optical system 100 is adopted in the image capturing module 200, and the overall length of the optical system 100 is shortened, so that the image capturing module 200 can be designed in a miniaturized manner.

Referring to fig. 13 and 14, in some embodiments, the image capturing module 200 may be applied to an electronic device 300, the electronic device includes a housing 310, and the image capturing module 200 is disposed in the housing 310. Specifically, the electronic apparatus 300 may be, but is not limited to, a wearable device such as a mobile phone, a video phone, a smart phone, an electronic book reader, a vehicle-mounted image capturing apparatus such as a car recorder, or a smart watch. The image capturing module 200 is adopted in the electronic device 300, and the electronic device 300 can be designed in a miniaturized manner by shortening the total length of the optical system 100.

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

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

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

a fifth lens element with negative refractive power;

and the optical system satisfies the following conditional expression:

0.6≤TTL/(ImgH*2)≤0.8；

wherein, TTL is the total system length of the optical system, and ImgH is half of the diagonal length of the effective pixel area on the imaging surface of the optical system.

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

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 plane.

3. The optical system of claim 2, wherein 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.

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

0.75≤DL/TTL≤1.1；

wherein DL is a distance on an optical axis from an object-side surface of the first lens element to an image-side surface of the seventh lens element, and TTL is a total system length of the optical system.

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

f23＜0；

wherein f23 is the combined focal length of the second lens and the third lens.

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

0≤R14/f≤1；

wherein R14 is a radius of curvature of an image-side surface of the seventh lens at an optical axis, and f is an effective focal length of the optical system.

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

|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.

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

|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.

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

(n1+n2)/f≤1mm^-1；

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

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

|R11/R14|≤3.0；

wherein R11 is a radius of curvature of an object-side surface of the sixth lens element at an optical axis, and R14 is a radius of curvature of an image-side surface of the seventh lens element at the optical axis.

11. An image capturing module, comprising a photosensitive element and the optical system of any one of claims 1 to 10, wherein the photosensitive element is disposed on an image side of the optical system.

12. An electronic device, comprising a housing and the image capturing module of claim 11, wherein the image capturing module is disposed on the housing.