CN111367055A

CN111367055A - Optical system, camera module and electronic equipment

Info

Publication number: CN111367055A
Application number: CN202010338872.4A
Authority: CN
Inventors: 蔡雄宇; 兰宾利; 周芮
Original assignee: Tianjin OFilm Opto Electronics Co Ltd
Current assignee: Tianjin OFilm Opto Electronics Co Ltd
Priority date: 2020-04-26
Filing date: 2020-04-26
Publication date: 2020-07-03

Abstract

The invention relates to an optical system, a camera 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; a third lens element with positive refractive power; a fourth lens; the fifth lens and the fourth lens form a lens group with positive refractive power; a sixth lens element with negative refractive power; and the optical system satisfies: -1.1 < Sag S10/CT5 < -0.5; sag S10 is the maximum sagittal height of the image-side surface of the fifth lens, and CT5 is the thickness of the fifth lens on the optical axis. When the optical system meets the lens configuration and the relational expression conditions, the central thickness of the fifth lens and the curvature degree of the image side surface of the fifth lens can be reasonably matched, so that the fifth lens can well correct the system aberration, and the imaging quality of the optical system is favorably improved.

Description

Optical system, camera module and electronic equipment

Technical Field

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

Background

Since the camera lens is applied to electronic devices such as smart phones and tablet computers, the performance of the camera lens also changes with the increase of high-quality camera shooting requirements of users. Among them, the continuous improvement of the photographing effect of the imaging lens is one of the centers of gravity expected for the advancement of science and technology. Especially, with the popularization of electronic devices with camera function in life, the quality of the image has become one of the key factors for people to select electronic products.

Disclosure of Invention

In view of the above, it is necessary to provide an optical system, an image pickup module, and an electronic apparatus, which are directed to the problem of how to improve the imaging quality.

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;

a third lens element with positive refractive power;

a fourth lens element with refractive power;

the fifth lens element with refractive power and the fourth lens element form a lens assembly with positive refractive power;

a sixth lens element with negative refractive power;

and the optical system satisfies the following relationship:

-1.1＜Sag S10/CT5＜-0.5；

wherein Sag S10 is the maximum sagittal height of the image side surface of the fifth lens, and CT5 is the thickness of the fifth lens on the optical axis.

When the optical system meets the lens configuration and the relational expression conditions, the central thickness of the fifth lens and the curvature degree of the image side surface of the fifth lens can be reasonably matched, so that the fifth lens can well correct the system aberration, and the imaging quality of the optical system is favorably improved. When the lower limit of the relation is lower, the image side surface of the fifth lens becomes over-bent, which is not beneficial to correcting the aberration of the optical system, thereby causing the reduction of the resolving power; when the thickness of the fifth lens is higher than the upper limit of the above relation, the thickness of the center of the fifth lens becomes too thick, which is not favorable for injection molding of the lens, and is easy to cause generation of stray light, thereby affecting the imaging quality.

In one embodiment, the optical system satisfies the following relationship:

1.2＜f123/CT123＜5.5；

wherein f123 is a combined focal length of the first lens element, the second lens element and the third lens element, and CT123 is a sum of thicknesses of the first lens element, the second lens element and the third lens element on an optical axis. When the above relationship is satisfied, the first lens element, the second lens element and the third lens element provide positive refractive power to the optical system as a whole, so that light beams incident into the optical system at a large angle can be contracted, and the light beams incident at the large angle can finally pass through the subsequent fourth lens element, the fifth lens element and the sixth lens element and converge to an imaging surface of the system. When the refractive power of the lens group formed by the first lens element, the second lens element and the third lens element exceeds the upper limit of the above relation, the total length of the system is increased, which is not favorable for the miniaturization of the system; when the value is lower than the lower limit of the above relation, the central thicknesses of the first lens, the second lens, and the third lens are too large, which is also disadvantageous to the miniaturization of the system.

In one embodiment, the optical system satisfies the following relationship:

6＜f1/CT1＜16；

wherein f1 is the effective focal length of the first lens, and CT1 is the thickness of the first lens on the optical axis. The first lens provides positive refractive power for the optical system, and when the above relation is satisfied, the focal length and the center thickness of the first lens can be reasonably configured, which is beneficial for the optical system to capture light beams incident at a large angle, so that the optical system has the characteristics of a wide angle of view and low sensitivity, and is also beneficial for shortening the total length of the optical system to satisfy the miniaturization design.

In one embodiment, the optical system satisfies the following relationship:

-6＜f2/f＜-1；

wherein f2 is the effective focal length of the second lens, and f is the effective focal length of the optical system. The second lens element provides negative refractive power for the optical system, can correct the positive refractive power of the first lens element, and is favorable for correcting astigmatism of the system, reducing sensitivity of the system and improving yield when the above relation is satisfied.

In one embodiment, the optical system satisfies the following relationship:

0.5＜f3/f＜3.2；

wherein f3 is an effective focal length of the third lens, and f is an effective focal length of the optical system. The third lens element provides positive refractive power for the optical system, and when the relationship is satisfied, the third lens element is favorable for correcting the problem of insufficient aberration correction of the first lens element by the system; meanwhile, the optical system can have stronger telephoto characteristic, namely, a larger depth of field range.

In one embodiment, the image side surface of the fourth lens is cemented with the object side surface of the fifth lens, and the optical system satisfies the following relationship:

2＜f45/(CT5-CT4)＜6；

wherein f45 is a combined focal length of the fourth lens element and the fifth lens element, CT4 is an optical thickness of the fourth lens element, and CT5 is an optical thickness of the fifth lens element. The fourth lens and the fifth lens form a cemented lens, and when the above relationship is satisfied, the central thicknesses of the fourth lens and the fifth lens and the focal length of the cemented lens can be reasonably controlled, which is beneficial to correcting astigmatism of the optical system and correcting high-order aberration of the optical system, so that the system resolving power can be improved to obtain better imaging quality; meanwhile, through the design meeting the relation, the problem that the glued joint is cracked due to different deformation quantities of the fourth lens and the fifth lens under the effect of expansion with heat and contraction with cold caused by the difference of lens materials can be solved.

In one embodiment, the optical system satisfies the following relationship:

-4.2＜f6/CT6＜-1.2；

wherein f6 is an effective focal length of the sixth lens element, and CT6 is an optical thickness of the sixth lens element. The sixth lens element provides negative refractive power for the optical system, and when the above relationship is satisfied, the focal length of the sixth lens element and the central thickness of the sixth lens element can be reasonably configured to increase the distance between the sixth lens element and the system imaging surface, thereby facilitating provision of a sufficient back focus focusing distance; meanwhile, the incident angle of the chief ray can be reduced, and the photosensitive performance of the photosensitive element is improved.

In one embodiment, the optical system satisfies the following relationship:

0.1＜ExPD/f＜0.7；

wherein ExPD is the exit pupil diameter of the optical system, and f is the effective focal length of the optical system. When the relation is satisfied, the visual field of the image surface of the optical system is brighter, so that the system has the effect of a large aperture and a larger depth of field range, namely a wider imaging depth, and is favorable for accurately identifying and judging imaging pictures from far to near. When the value is higher than the upper limit of the above relationship, the wide-angle design of the optical system and the improvement of the field brightness are not facilitated.

In one embodiment, the optical system satisfies the following relationship:

0.2mm＜TTL/tan FOV＜2.2mm；

wherein, TTL is the total system length of the optical system, FOV is the maximum field angle of the optical system, TTL unit is millimeter, and FOV unit is degree. When the relation is satisfied, the miniaturization design of the optical system is facilitated, and the requirement of shooting at a large angle is satisfied.

In one embodiment, the optical system satisfies the following relationship:

0.5＜Imgh/f＜2.2；

where Imgh is an image height corresponding to a maximum field angle of the optical system, and f is an effective focal length of the optical system. When the above relation is satisfied, it is advantageous to realize a miniaturized design of the optical system and to ensure a high pixel requirement.

In one embodiment, the object-side surface of the second lens element is convex at the paraxial region and the image-side surface of the second lens element is concave at the paraxial region; the object side surface of the third lens is a convex surface at the paraxial position, and the image side surface of the third lens is a convex surface or a concave surface at the paraxial position; the object side surface of the fourth lens is a concave surface at the paraxial position, and the image side surface of the fourth lens is a convex surface at the paraxial position; the object side surface of the fifth lens is a concave surface at the paraxial position, and the image side surface of the fifth lens is a convex surface at the paraxial position; the object side surface of the sixth lens element is convex or concave at the paraxial region, and the image side surface of the sixth lens element is concave at the paraxial region. Through the concave-convex matching of the surface shapes, the structure of the lens system is more compact, and the miniaturization design is realized.

In one embodiment, an inflection point exists on at least one of the object-side surface and the image-side surface of the sixth lens. The design is beneficial to the pixel optimization of the marginal field of view of the lens 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 on an image side of the optical system. Through adopting above-mentioned optical system, will be favorable to improving the imaging quality of the module of making a video recording improves the performance of making a video recording of module.

An electronic device comprises a fixing piece and the camera module, wherein the camera module is arranged on the fixing piece. Through adopting above-mentioned module of making a video recording, electronic equipment will have good performance of making a video recording.

Drawings

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

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

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

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

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

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

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

FIG. 8 is a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system in a fourth embodiment;

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

FIG. 10 is a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system in a fifth embodiment;

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

fig. 12 is a schematic view of an electronic device according to an embodiment of the present application.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" 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. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1, in some embodiments of the present application, the optical system 10 includes, in order from an object side to an image side, a stop STO, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6, and each of the first lens L1 to the sixth lens L6 includes only one lens. The first lens element L1 has positive refractive power, the second lens element L2 has negative refractive power, the third lens element L3 has positive refractive power, the fourth lens element L4 has positive refractive power or negative refractive power, the fifth lens element L5 has positive refractive power or negative refractive power, and the sixth lens element L6 has negative refractive power. Each lens in the optical system 10 is arranged coaxially with the stop STO, that is, the optical axis of each lens and the center of the stop STO are located on the same straight line, which may be referred to as the optical axis of the optical system 10. The stop STO is disposed on the object side of the first lens L1, and the design with the stop STO in front is favorable for the miniaturization of the optical system 10. Of course, the position of the stop STO in some embodiments can be changed according to actual situations, for example, in some embodiments, the stop STO can also be disposed between any two adjacent lenses in the optical system 10.

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, and the sixth lens L6 includes an object side surface S11 and an image side surface S12. In addition, the optical system 10 further has a virtual image plane S13, and the image plane S13 is located on the image side of the sixth lens element L6. Generally, the image forming surface S13 of the optical system 10 coincides with the photosensitive surface of the photosensitive element, which can be regarded as the image forming surface S13 of the optical system 10 for ease of understanding.

In addition, in the optical system 10, the object-side surface S1 of the first lens element L1 is convex at the paraxial region, and the image-side surface S2 is concave at the paraxial region, and the optical system 10 satisfies the relationship:

-1.1 < Sag S10/CT5 < -0.5; here, Sag S10 is the maximum rise of the image-side surface S10 of the fifth lens L5, and CT5 is the thickness of the fifth lens L5 on the optical axis. Specifically, Sag S10 is a distance in the direction parallel to the optical axis from the center of the image-side surface S10 of the fifth lens L5 (the intersection of the surface with the optical axis) to the maximum effective radius of the surface. When Sag S10 is negative, the center of the plane is closer to the image side of the system than at the maximum effective radius in a direction parallel to the optical axis of the system; when Sag S10 is positive, the center of the surface is closer to the object side of the system than at the maximum effective radius, in a direction parallel to the optical axis of the system. Specifically, Sag S10/CT5 in some embodiments can be-1.04, -1.02, -1, -0.95, -0.9, -0.85, or-0.82. When the optical system 10 satisfies the lens arrangement and the relation conditions of the above embodiments, the central thickness of the fifth lens L5 and the curvature degree of the image-side surface S10 of the fifth lens L5 can be reasonably matched, so that the fifth lens L5 can perform good correction on system aberration, thereby being beneficial to improving the imaging quality of the optical system 10. When the lower limit of the above relation is exceeded, the image-side surface S10 of the fifth lens L5 becomes excessively curved, which is disadvantageous in correcting aberrations of the optical system 10, resulting in a decrease in resolving power; when the thickness of the fifth lens L5 is higher than the upper limit of the above relation, the thickness of the fifth lens L5 becomes too thick, which is not favorable for injection molding of the lens, and is liable to cause stray light, thereby affecting the imaging quality.

In particular, in some embodiments, the object-side surface S3 of the second lens L2 is convex paraxially, and the image-side surface S4 is concave paraxially; the object-side surface S5 of the third lens element L3 is convex at the paraxial region thereof, and the image-side surface S6 is convex or concave at the paraxial region thereof; the object-side surface S7 of the fourth lens element L4 is concave at the paraxial region thereof, and the image-side surface S8 is convex at the paraxial region thereof; the object-side surface S9 of the fifth lens element L5 is concave at the paraxial region thereof, and the image-side surface S10 is convex at the paraxial region thereof; the object-side surface S11 of the sixth lens element L6 is convex or concave at the paraxial region thereof, and the image-side surface S12 is concave at the paraxial region thereof. Through the concave-convex matching of the surface shapes, the structure of the lens system is more compact, and the miniaturization design is realized.

In addition, in the above-described embodiment, the image-side surface S8 of the fourth lens L4 is cemented with the object-side surface S9 of the fifth lens L5, so that the fourth lens L4 and the fifth lens L5 constitute a cemented lens. The cemented lens assembly formed by the fourth lens element L4 and the fifth lens element L5 provides positive refractive power to the optical system 10, thereby facilitating the correction of aberration and the miniaturization of the system, which makes the system achieve a balance between reducing the size and improving the resolution. In addition, the risk of the fourth lens L4 and the fifth lens L5 being tilted and decentered as a whole during the assembly process can be reduced.

In the above embodiment, the object-side surface and the image-side surface of each lens in the optical system 10 are aspheric, and the aspheric design enables the object-side surface and/or the image-side surface of each lens to have a more flexible design, so that the lens can well solve the problems of poor imaging, distorted field of view, narrow field of view and the like under the condition of being small and thin, and thus the system can have good imaging quality without arranging too many lenses, and is beneficial to shortening the length of the optical system 10. In some embodiments, the object-side surface and the image-side surface of each lens in the optical system 10 are both spherical surfaces, and the spherical lenses are simple in manufacturing process and low in production cost. In other embodiments, the object-side surfaces of some lenses in the optical system 10 are aspheric, the object-side surfaces of other lenses are spherical, the image-side surfaces of some lenses are aspheric, and the image-side surfaces of other lenses are aspheric. The specific configurations of the spherical surface and the aspherical surface in some embodiments are determined according to actual design requirements, and are not described herein. The aberration of the system can be effectively eliminated by the cooperation of the spherical surface and the aspherical surface, so that the optical system 10 has good imaging quality, and simultaneously, the flexibility of lens design and assembly is improved, and the system is balanced between high imaging quality and low cost. It is to be noted that the specific shapes of the spherical and aspherical surfaces in the embodiments are not limited to those shown in the drawings, which are mainly for exemplary reference and are not drawn strictly to scale.

The surface shape of the aspheric surface can be calculated by referring to an aspheric surface formula:

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.

In the above embodiment, the object side surface S11 and the image side surface S12 of the sixth lens L6 both have an inflection point. In some embodiments, the object side S11 of the sixth lens L6 has an inflection point, and the image side S12 has no inflection point. In other embodiments, the object side S11 of the sixth lens L6 has no inflection point, and the image side S12 has an inflection point. By setting the inflection point on the sixth lens L6, the optimization of the pixels of the marginal field of view of the system is facilitated, and the imaging quality is improved.

In the above embodiment, the material of each lens in the optical system 10 is plastic. In other embodiments, each lens of the optical system 10 is made of glass. The plastic lens can reduce the weight of the optical system 10 and the manufacturing cost, while the glass lens can withstand higher temperatures and has excellent optical effects. In other embodiments, the first lens L1 is made of glass, and the second lens L2 to the sixth lens L6 are made of plastic, so that the lens located at the object side in the optical system 10 is made of glass, and therefore, the glass lenses located at the object side have a good tolerance effect on extreme environments, and are not susceptible to aging and the like caused by the influence of the object side environment, so that when the optical system 10 is in the extreme environments such as exposure to high temperature, the optical performance and cost of the system can be well balanced by the structure. Of course, the configuration relationship of the lens materials in the optical system 10 is not limited to the above embodiments, any one of the lenses may be made of plastic or glass, and the specific configuration relationship is determined according to the actual design requirement, which is not described herein again.

In some embodiments, the optical system 10 includes a filter L7, and the filter L7 is disposed on the image side of the sixth lens L6 and is fixed to each lens in the optical system 10. The filter L7 is an infrared cut filter for filtering out infrared light, and prevents the infrared light from reaching the imaging surface S13 of the system, thereby preventing the infrared light from interfering with normal imaging. The filter L7 may be assembled with each lens as part of the optical system 10. For example, in some embodiments, each lens in the optical system 10 is mounted in a lens barrel, and the filter L7 is mounted at the image end of the lens barrel. In other embodiments, the filter L7 is not part of the optical system 10, and the filter L7 may be installed between the optical system 10 and the photosensitive element when the optical system 10 and the photosensitive element are assembled into a camera module. In some embodiments, the optical filter L7 may also be disposed on the object side of the first lens L1. In addition, in some embodiments, the filter L7 may not be provided, and an infrared filter is provided on an object side surface or an image side surface of one of the first lens L1 to the sixth lens L6 to filter infrared light.

In some embodiments, the first lens element L1 may also include two or more lens elements, wherein the object-side surface of the lens element closest to the object side is the object-side surface S1 of the first lens element L1, and the image-side surface of the lens element closest to the image side is the image-side surface S2 of the first lens element L1. Accordingly, any one of the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 in some embodiments is not limited to the case where only one lens is included.

In some embodiments, the optical system 10 further satisfies at least one of the following relationships, and when any one of the following relationship conditions is satisfied, the optical system 10 can have the effect corresponding to the corresponding relationship:

f123/CT123 is more than 1.2 and less than 5.5; wherein f123 is a combined focal length of the first lens L1, the second lens L2 and the third lens L3, and CT123 is a sum of thicknesses of the first lens L1, the second lens L2 and the third lens L3 on an optical axis. Specifically, f123/CT123 in some embodiments may be 2.96, 3, 3.1, 3.2, 3.5, 3.6, 4, 4.4, 4.5, 4.55, or 4.58. When the above relationship is satisfied, the first lens element L1, the second lens element L2, and the third lens element L3 provide positive refractive power to the optical system 10 as a whole, so that the light beams incident into the optical system 10 at a large angle can be contracted, and the light beams incident at a large angle can finally pass through the subsequent fourth lens element L4, the fifth lens element L5, and the sixth lens element L6 and converge to the image plane of the system. When the upper limit of the above relation is exceeded, the refractive power of the lens assembly formed by the first lens element L1, the second lens element L2 and the third lens element L3 is insufficient, which leads to an increase in the overall length of the system and is not favorable for the miniaturization of the system; if the value is less than the lower limit of the above relational expression, the center thicknesses of the first lens L1, the second lens L2, and the third lens L3 are too large, which is also disadvantageous in downsizing the system.

6 < f1/CT1 < 16; where f1 is the effective focal length of the first lens element L1, and CT1 is the thickness of the first lens element L1 on the optical axis. Specifically, f1/CT1 in some embodiments can be 8.3, 8.4, 8.8, 9, 9.5, 9.6, 10, 11, 12, 13, 13.5, 14, or 14.3. The first lens element L1 provides positive refractive power to the optical system 10, and when the above relationship is satisfied, the focal length and the center thickness of the first lens element L1 can be reasonably configured, which is favorable for the optical system 10 to capture light beams with large angle incidence, so that the optical system 10 has characteristics of wide angle of view and low sensitivity, and also contributes to shortening the total length of the optical system 10 to satisfy the miniaturization design.

-6 < f2/f < -1; where f2 is the effective focal length of the second lens L2, and f is the effective focal length of the optical system 10. Specifically, f2/f in some embodiments can be-5, -4.9, -4.8, -4.5, -4, -3.8, -3.5, -3, -2.9, or-2.8. The second lens element L2 provides negative refractive power to the optical system 10, and can correct the positive refractive power of the first lens element L1, and when the above relationship is satisfied, it is favorable for correcting astigmatism of the system, reducing system sensitivity, and increasing yield.

F3/f is more than 0.5 and less than 3.2; where f3 is the effective focal length of the third lens L3, and f is the effective focal length of the optical system 10. Specifically, f3/f in some embodiments may be 1.7, 1.8, 2, 2.1, 2.3, 2.5, 2.7, or 2.8. The third lens element L3 provides positive refractive power to the optical system 10, and when the above relationship is satisfied, it is favorable for correcting the problem of insufficient aberration correction caused by the system on the first lens element L1; and also enables the optical system 10 to have a more telephoto characteristic, i.e., a larger depth of field range.

The image-side surface S8 of the fourth lens L4 is cemented with the object-side surface S9 of the fifth lens L5, and the optical system 10 satisfies the following relationship: 2 < f45/(CT5-CT4) < 6; wherein f45 is a combined focal length of the fourth lens L4 and the fifth lens L5, CT4 is an optical thickness of the fourth lens L4, and CT5 is an optical thickness of the fifth lens L5. Specifically, f45/(CT5-CT4) in some embodiments may be 4, 4.1, 4.2, 4.5, 5, 5.3, 5.4, 5.5, 5.7, or 5.8. The fourth lens L4 and the fifth lens L5 form a cemented lens, and when the above relationship is satisfied, the central thicknesses of the fourth lens L4 and the fifth lens L5 and the focal length of the cemented lens can be reasonably controlled, which is beneficial to correcting astigmatism of the optical system 10 and correcting high-order aberration of the optical system 10, so that the system resolving power can be improved to obtain better imaging quality; meanwhile, through the design satisfying the above relationship, the problem that the cemented part is cracked due to different deformation amounts of the fourth lens L4 and the fifth lens L5 under the effect of expansion with heat and contraction with cold due to the difference of lens materials can be avoided.

-4.2 < f6/CT6 < -1.2; where f6 is the effective focal length of the sixth lens element L6, and CT6 is the thickness of the sixth lens element L6 along the optical axis. Specifically, f6/CT6 in some embodiments can be-3.9, -3.8, -3.5, -3.1, -3, -2.9, or-2.8. The sixth lens element L6 provides negative refractive power for the optical system 10, and when the above relationship is satisfied, the focal length of the sixth lens element L6 and the central thickness of the sixth lens element L6 can be reasonably configured to increase the distance between the sixth lens element L6 and the system image plane, so as to facilitate providing a sufficient back focus adjustment distance; meanwhile, the incident angle of the chief ray can be reduced, and the photosensitive performance of the photosensitive element is improved.

ExPD/f is more than 0.1 and less than 0.7; where ExPD is the exit pupil diameter of the optical system 10 and f is the effective focal length of the optical system 10. Specifically, ExPD/f in some embodiments may be 0.38, 0.4, 0.41, 0.42, 0.47, 0.48, 0.5, 0.52, or 0.54. When the above relationship is satisfied, the field of view of the image plane of the optical system 10 is brighter, so that the system has a large aperture effect and a larger depth of field range, i.e., a wider imaging depth, thereby facilitating accurate identification and judgment of the imaging picture from far to near. If the upper limit of the above relationship is exceeded, the design of the wide angle of the optical system 10 and the improvement of the field brightness are not facilitated.

TTL/tan FOV is more than 0.2mm and less than 2.2 mm; wherein, TTL is the total system length of the optical system 10, i.e., the distance from the object-side surface S1 of the first lens element L1 to the imaging surface S13 of the system on the optical axis, the FOV is the maximum field angle of the optical system 10, the unit of TTL is mm, and the unit of FOV is degree. Specifically, the TTL/tan FOV in some embodiments may be 0.38, 0.4, 0.45, 0.5, 0.55, 0.7, 0.72, 1, 1.4, 1.6, 1.8, or 1.9. Satisfying the above relationship is advantageous for the optical system 10 to achieve a compact design, and satisfies the requirement for large-angle shooting.

Imgh/f is more than 0.5 and less than 2.2; where Imgh is the image height corresponding to the maximum field angle of the optical system 10, and f is the effective focal length of the optical system 10. Specifically, Imgh/f in some embodiments may be 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, or 1.85. Satisfying the above relationship is advantageous in realizing a compact design of the optical system 10 and in ensuring a high pixel requirement of the system.

The optical system 10 of the present application is described in more detail with reference to the following examples:

first embodiment

Referring to fig. 1, in the first embodiment, the optical system 10 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, and a sixth lens element L6 with negative refractive power. Fig. 2 includes a longitudinal spherical aberration diagram, an astigmatism diagram, and a distortion diagram of the optical system 10 in the first embodiment. The reference wavelength of the systems of the following embodiments (first to fifth embodiments) was 555 nm.

The object-side surface S1 of the first lens element L1 is convex paraxially, and the image-side surface S2 is concave paraxially; the object side S1 is convex at the circumference, and the image side S2 is convex at the circumference.

The object-side surface S3 of the second lens element L2 is convex at the paraxial region, and the image-side surface S4 is concave at the paraxial region; object side S3 is concave at the circumference, and image side S4 is convex at the circumference.

The object-side surface S5 of the third lens element L3 is convex paraxially, and the image-side surface S6 is convex paraxially; the object side S5 is convex at the circumference, and the image side S6 is convex at the circumference.

The object-side surface S7 of the fourth lens element L4 is concave at the paraxial region thereof, and the image-side surface S8 is convex at the paraxial region thereof; object side S7 is concave at the circumference, and image side S8 is convex at the circumference.

The object-side surface S9 of the fifth lens element L5 is concave at the paraxial region thereof, and the image-side surface S10 is convex at the paraxial region thereof; object side S9 is concave at the circumference, and image side S10 is convex at the circumference.

The object-side surface S11 of the sixth lens element L6 is concave at the paraxial region thereof, and the image-side surface S12 is concave at the paraxial region thereof; the object side S11 is convex at the circumference, and the image side S12 is convex at the circumference.

The surface design is beneficial to enabling the structure of the lens system to be more compact and realizing the miniaturization characteristic.

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 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 paraxial region and also convex at the peripheral region, the shape of the surface from the center (optical axis) to the edge direction may be purely convex, or may first transition from a convex shape at the center to a concave shape and then become convex near the maximum effective radius. Here, the examples are only made for explaining the relationship between the optical axis and the circumference, and various shapes and structures (concave-convex relationship) of the surface are not completely embodied, but other situations in some embodiments can be derived according to the above examples, and are not described herein.

The image-side surface S8 of the fourth lens element L4 is cemented with the object-side surface S9 of the fifth lens element L5, so that the fourth lens element L4 and the fifth lens element L5 form a cemented lens, and the cemented lens provides positive refractive power for the optical system 10.

As described above, on the premise of ensuring high resolution performance of the system, the stop STO of the optical system 10 is disposed on the object side of the first lens L1, and the fourth lens L4 and the fifth lens L5 constitute a cemented lens, so that the system can be downsized, the risk of the fourth lens L4 and the fifth lens L5 being tilted and decentered as a whole during the assembly process can be reduced, the sensitivity of the system can be reduced, and the processing cost of the lenses can be reduced.

The object-side surface and the image-side surface of each lens in the optical system 10 are aspheric. The aspheric design can solve the problems of unclear imaging, distorted field of view, narrow field of view and the like well under the condition that the lens is small and thin, optimize pixels of the marginal field of view of the system, and contribute to shortening the length of the optical system 10. In the optical system 10, each lens is made of plastic.

In the first embodiment, the optical system 10 satisfies the following relationships:

sag S10/CT5 ═ 0.82; here, Sag S10 is the maximum rise of the image-side surface S10 of the fifth lens L5, and CT5 is the thickness of the fifth lens L5 on the optical axis. Specifically, Sag S10 is a distance in the direction parallel to the optical axis from the center of the image-side surface S10 of the fifth lens L5 (the intersection of the surface with the optical axis) to the maximum effective radius of the surface. When Sag S10 is negative, the center of the plane is closer to the image side of the system than at the maximum effective radius in a direction parallel to the optical axis of the system; when Sag S10 is positive, the center of the surface is closer to the object side of the system than at the maximum effective radius, in a direction parallel to the optical axis of the system. When the optical system 10 satisfies the lens arrangement and the relation conditions of the above embodiments, the central thickness of the fifth lens L5 and the curvature degree of the image-side surface S10 of the fifth lens L5 can be reasonably matched, so that the fifth lens L5 can perform good correction on system aberration, thereby being beneficial to improving the imaging quality of the optical system 10.

f123/CT123 is 2.958; wherein f123 is a combined focal length of the first lens L1, the second lens L2 and the third lens L3, and CT123 is a sum of thicknesses of the first lens L1, the second lens L2 and the third lens L3 on an optical axis. When the above relationship is satisfied, the first lens element L1, the second lens element L2, and the third lens element L3 provide positive refractive power to the optical system 10 as a whole, so that the light beams incident into the optical system 10 at a large angle can be contracted, and the light beams incident at a large angle can finally pass through the subsequent fourth lens element L4, the fifth lens element L5, and the sixth lens element L6 and converge to the image plane of the system.

f1/CT1 is 11.32; where f1 is the effective focal length of the first lens element L1, and CT1 is the thickness of the first lens element L1 on the optical axis. The first lens element L1 provides positive refractive power to the optical system 10, and when the above relationship is satisfied, the focal length and the center thickness of the first lens element L1 can be reasonably configured, which is favorable for the optical system 10 to capture light beams with large angle incidence, so that the optical system 10 has characteristics of wide angle of view and low sensitivity, and also contributes to shortening the total length of the optical system 10 to satisfy the miniaturization design.

f 2/f-5; where f2 is the effective focal length of the second lens L2, and f is the effective focal length of the optical system 10. The second lens element L2 provides negative refractive power to the optical system 10, and can correct the positive refractive power of the first lens element L1, and when the above relationship is satisfied, it is favorable for correcting astigmatism of the system, reducing system sensitivity, and increasing yield.

f3/f 1.681; where f3 is the effective focal length of the third lens L3, and f is the effective focal length of the optical system 10. The third lens element L3 provides positive refractive power to the optical system 10, and when the above relationship is satisfied, it is favorable for correcting the problem of insufficient aberration correction caused by the system on the first lens element L1; and also enables the optical system 10 to have a more telephoto characteristic, i.e., a larger depth of field range.

The image-side surface S8 of the fourth lens L4 is cemented with the object-side surface S9 of the fifth lens L5, and the optical system 10 satisfies the following relationship: f45/(CT5-CT4) ═ 5.84; wherein f45 is a combined focal length of the fourth lens L4 and the fifth lens L5, CT4 is an optical thickness of the fourth lens L4, and CT5 is an optical thickness of the fifth lens L5. The fourth lens L4 and the fifth lens L5 form a cemented lens, and when the above relationship is satisfied, the central thicknesses of the fourth lens L4 and the fifth lens L5 and the focal length of the cemented lens can be reasonably controlled, which is beneficial to correcting astigmatism of the optical system 10 and correcting high-order aberration of the optical system 10, so that the system resolving power can be improved to obtain better imaging quality; meanwhile, through the design satisfying the above relationship, the problem that the cemented part is cracked due to different deformation amounts of the fourth lens L4 and the fifth lens L5 under the effect of expansion with heat and contraction with cold due to the difference of lens materials can be avoided.

f6/CT6 is-3.99; where f6 is the effective focal length of the sixth lens element L6, and CT6 is the thickness of the sixth lens element L6 along the optical axis. The sixth lens element L6 provides negative refractive power for the optical system 10, and when the above relationship is satisfied, the focal length of the sixth lens element L6 and the central thickness of the sixth lens element L6 can be reasonably configured to increase the distance between the sixth lens element L6 and the system image plane, so as to facilitate providing a sufficient back focus adjustment distance; meanwhile, the incident angle of the chief ray can be reduced, and the photosensitive performance of the photosensitive element is improved.

ExPD/f is 0.406; where ExPD is the exit pupil diameter of the optical system 10 and f is the effective focal length of the optical system 10. When the above relationship is satisfied, the field of view of the image plane of the optical system 10 is brighter, so that the system has a large aperture effect and a larger depth of field range, i.e., a wider imaging depth, thereby facilitating accurate identification and judgment of the imaging picture from far to near.

TTL/tan FOV is 0.518 mm; wherein, TTL is the total system length of the optical system 10, FOV is the maximum field angle of the optical system 10, TTL is millimeters, and FOV is degrees. Satisfying the above relationship is advantageous for the optical system 10 to achieve a compact design, and satisfies the requirement for large-angle shooting.

1.528 for Imgh/f; where Imgh is the image height corresponding to the maximum field angle of the optical system 10, and f is the effective focal length of the optical system 10. Satisfying the above relationship is advantageous in realizing a compact design of the optical system 10 and in ensuring a high pixel requirement of the system.

In addition, each lens parameter of the optical system 10 is given by table 1 and table 2. Table 2 shows aspheric coefficients of the respective surfaces of the respective lenses in table 1, where K is a conic coefficient and Ai is a coefficient corresponding to the i-th high-order term in the aspheric surface type formula. The elements from the object side to the image side are arranged in the order of the elements from the top to the bottom in table 1, and the image plane (image forming plane S13) can be understood as the photosensitive surface of the photosensitive element at the later stage when the photosensitive element is assembled. The surface numbers 2 and 3 correspond to the object-side surface S1 and the image-side surface S2 of the first lens L1, respectively, that is, 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. 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. The first value of the lens in the "thickness" parameter set is the thickness of the lens on the optical axis, and the second value is the distance from the image-side surface of the lens to the object-side surface of the next optical element on the optical axis. The numerical value of the stop ST0 in the "thickness" parameter column is the distance on the optical axis from the stop ST0 to the vertex of the object-side surface of the subsequent lens (the vertex refers to the intersection point of the lens and the optical axis), the direction from the object side to the image side is the positive direction of the optical axis by default, when the value is negative, it indicates that the stop ST0 is disposed on the right side of the vertex of the object-side surface of the lens (i.e. the vertex of the object-side surface passes through the stop STO), and when the "thickness" parameter of the stop STO is positive, the stop ST0 is on the left side of the vertex of the object. The optical axes of the lenses in the embodiment of the present application are on the same straight line as the optical axis of the optical system 10. In addition, the relational expression calculation and the lens structure of each example are based on data in parameter tables (e.g., table 1, table 2, table 3, table 4, etc.).

In the first embodiment, the effective focal length f of the optical system 10 is 3.71mm, the f-number FNO is 1.95, the maximum field angle (i.e., the maximum angle of view in the diagonal direction) FOV of the optical system 10 is 84 °, and the total system length TTL is 4.927mm, which is the sum of the values of the "thickness" parameters in the following plane number 1 to plane number 15.

TABLE 1

TABLE 2

Second embodiment

Referring to fig. 3, in the second embodiment, the optical system 10 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, and a sixth lens element L6 with negative refractive power. Fig. 4 includes a longitudinal spherical aberration diagram, an astigmatism diagram, and a distortion diagram of the optical system 10 in the second embodiment.

The object-side surface S5 of the third lens element L3 is convex paraxially, and the image-side surface S6 is concave paraxially; the object side S5 is convex at the circumference, and the image side S6 is convex at the circumference.

The object-side surface S11 of the sixth lens element L6 is convex and the image-side surface S12 is concave; the object side S11 is convex at the circumference, and the image side S12 is convex at the circumference.

In addition, the lens parameters of the optical system 10 in the second embodiment are shown in tables 3 and 4, wherein the definitions of the structures and parameters can be obtained from the first embodiment, which is not repeated herein.

TABLE 3

TABLE 4

Number of noodles

2

3

4

5

6

7

K

2.82E+00

8.78E+00

2.98E+01

-2.44E+00

-3.17E+01

-1.45E+01

A4

-5.56E-02

-4.32E-02

-3.88E-02

-5.32E-02

-4.65E-02

-1.75E-02

A6

-2.05E-02

-3.61E-03

3.79E-03

-2.37E-02

-1.08E-02

-2.10E-02

A8

-9.02E-02

-3.58E-02

-4.72E-02

-6.14E-03

-4.92E-03

2.04E-02

A10

4.16E-01

-2.15E-02

-5.92E-03

-7.83E-03

9.43E-03

3.59E-03

A12

-9.51E-01

5.76E-02

1.84E-02

-5.13E-03

1.11E-02

-3.47E-03

A14

9.19E-01

-4.36E-02

-4.94E-03

2.72E-02

5.20E-03

1.92E-04

A16

-3.43E-01

1.24E-02

3.39E-03

-1.11E-02

-5.56E-03

-3.74E-05

A18

0.00E+00

A20

0.00E+00

Number of noodles

8

9

10

11

12

13

K

1.48E+00

2.05E-01

-1.12E+00

-7.69E-02

-4.03E+00

A4

-4.80E-02

-6.55E-03

-2.44E-02

-2.29E-01

-9.30E-02

A6

-1.00E-01

-5.96E-02

3.68E-02

1.71E-01

4.85E-02

A8

1.95E-01

3.22E-02

-2.52E-02

-7.29E-02

-1.54E-02

A10

-2.24E-01

-6.59E-03

1.22E-02

1.80E-02

3.05E-03

A12

8.21E-02

6.55E-03

-4.51E-03

-2.47E-03

-3.70E-04

A14

2.80E-02

-3.89E-03

8.28E-04

1.75E-04

2.53E-05

A16

-2.22E-02

6.21E-04

-2.99E-05

-4.97E-06

-7.42E-07

A18

0.00E+00

A20

0.00E+00

The optical system 10 in this embodiment satisfies the following relationship:

f123/CT123	3.591	f6/CT6	-3.16
				f1/CT1	9.54	Sag S10/CT5	-0.96
f2/f	-3.85	ExPD/f	0.378
				f3/f	2.867	TTL/tan FOV	1.926
f45/(CT5-CT4)	4.568	Imgh/f	1.789

third embodiment

Referring to fig. 5, in the third embodiment, the optical system 10 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, and a sixth lens element L6 with negative refractive power. Fig. 6 includes a longitudinal spherical aberration diagram, an astigmatism diagram, and a distortion diagram of the optical system 10 in the third embodiment.

The object-side surface S1 of the first lens element L1 is convex paraxially, and the image-side surface S2 is concave paraxially; the object side S1 is convex at the circumference, and the image side S2 is concave at the circumference.

The object-side surface S5 of the third lens element L3 is convex paraxially, and the image-side surface S6 is concave paraxially; object side S5 is concave at the circumference, and image side S6 is convex at the circumference.

In addition, the lens parameters of the optical system 10 in the third embodiment are given in tables 5 and 6, wherein the definitions of the structures and parameters can be obtained from the first embodiment, which are not repeated herein.

TABLE 5

TABLE 6

The optical system 10 in this embodiment satisfies the following relationship:

f123/CT123	4.592	f6/CT6	-3.57
				f1/CT1	13.9	Sag S10/CT5	-1.04
f2/f	-4.16	ExPD/f	0.479
				f3/f	2.313	TTL/tan FOV	0.704
f45/(CT5-CT4)	5.342	Imgh/f	1.868

fourth embodiment

Referring to fig. 7, in the fourth embodiment, the optical system 10 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with positive refractive power, and a sixth lens element L6 with negative refractive power. Fig. 8 includes a longitudinal spherical aberration diagram, an astigmatism diagram, and a distortion diagram of the optical system 10 in the fourth embodiment.

The object-side surface S5 of the third lens element L3 is convex paraxially, and the image-side surface S6 is convex paraxially; object side S5 is concave at the circumference, and image side S6 is convex at the circumference.

In addition, the lens parameters of the optical system 10 in the fourth embodiment are given in tables 7 and 8, wherein the definitions of the structures and parameters can be obtained from the first embodiment, which is not repeated herein.

TABLE 7

TABLE 8

Number of noodles

2

3

4

5

6

7

K

3.15E+00

4.64E+00

-2.35E+01

-6.50E+01

-2.33E+01

7.37E+00

A4

-4.12E-02

-2.78E-02

-7.69E-02

-7.35E-02

-6.21E-02

-1.92E-02

A6

-2.63E-02

-6.99E-03

3.31E-02

-2.87E-03

-2.76E-02

-5.02E-02

A8

-1.18E-01

-2.86E-02

-4.12E-02

3.36E-04

-1.55E-02

-4.51E-03

A10

4.47E-01

-3.02E-02

-1.44E-02

-1.10E-02

4.76E-03

3.00E-03

A12

-9.44E-01

4.61E-02

8.47E-03

-1.08E-02

1.18E-02

7.71E-04

A14

8.95E-01

-4.64E-02

-9.93E-03

2.24E-02

8.38E-03

1.91E-03

A16

-3.46E-01

1.60E-02

4.73E-03

-1.12E-02

-5.68E-03

1.11E-03

A18

0.00E+00

A20

0.00E+00

Number of noodles

8

9

10

11

12

13

K

-1.11E+01

-5.62E+01

-2.38E+00

2.34E+00

-4.88E+00

A4

-1.40E-01

-2.33E-02

-5.78E-02

-3.29E-02

-4.12E-02

A6

-8.96E-02

-7.48E-02

2.82E-02

1.02E-02

1.67E-02

A8

2.24E-01

4.26E-02

-2.18E-02

-2.77E-03

-4.79E-03

A10

-2.19E-01

-2.85E-03

1.34E-02

4.21E-04

8.81E-04

A12

7.18E-02

5.14E-03

-4.30E-03

-3.15E-05

-1.01E-04

A14

2.22E-02

-5.37E-03

8.10E-04

1.11E-06

6.44E-06

A16

-1.55E-02

1.18E-03

-6.69E-05

-1.49E-08

-1.74E-07

A18

0.00E+00

A20

0.00E+00

The optical system 10 in this embodiment satisfies the following relationship:

f123/CT123	3.914	f6/CT6	-3.16
				f1/CT1	14.48	Sag S10/CT5	-0.99
f2/f	-4.66	ExPD/f	0.54
				f3/f	1.665	TTL/tan FOV	0.519
f45/(CT5-CT4)	3.927	Imgh/f	1.833

fifth embodiment

Referring to fig. 9, in the fifth embodiment, the optical system 10 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with positive refractive power, and a sixth lens element L6 with negative refractive power. Fig. 10 includes a longitudinal spherical aberration diagram, an astigmatism diagram, and a distortion diagram of the optical system 10 in the fifth embodiment.

In addition, the lens parameters of the optical system 10 in the fifth embodiment are given in tables 9 and 10, wherein the definitions of the structures and parameters can be obtained from the first embodiment, which are not repeated herein.

TABLE 9

Watch 10

The optical system 10 in this embodiment satisfies the following relationship:

f123/CT123	3.524	f6/CT6	-2.76
				f1/CT1	8.23	Sag S10/CT5	-0.92
f2/f	-2.77	ExPD/f	0.416
				f3/f	2.024	TTL/tan FOV	0.374
f45/(CT5-CT4)	4.146	Imgh/f	1.868

referring to fig. 11, some embodiments of the present application further provide an image capturing module 20, in which the optical system 10 is assembled with the photosensitive element 210 to form the image capturing module 20, and the photosensitive element 210 is disposed on the image side of the sixth lens element L6, i.e., on the image side of the optical system 10. Generally, the photosensitive surface of the photosensitive element 210 overlaps with the image forming surface S13 of the optical system 10, or the photosensitive surface may also be understood as the image forming surface S13. The photosensitive element 210 may be a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). Through adopting above-mentioned optical system 10, will be favorable to improving the formation of image quality of the module of making a video recording 20, improve the performance of making a video recording of module.

In some embodiments, a filter L7 is further disposed between the sixth lens L6 and the imaging surface S13 of the system, and the filter L7 is used for filtering infrared light. The optical filter L7 may be a part of the optical system 10, or may be mounted between the optical system 10 and the light-receiving element 210 together when the optical system 10 and the light-receiving element 210 are assembled.

In some embodiments, the distance between the photosensitive element 210 and each lens in the optical system 10 is relatively fixed, and the camera module 20 is a fixed focus module. In other embodiments, a driving mechanism such as a voice coil motor may be provided to enable the photosensitive element 210 to move relative to each lens in the optical system 10, so as to achieve a focusing effect. Specifically, a coil electrically connected to the driving chip is disposed on the lens barrel to which the above lenses are assembled, and a magnet is disposed in the image pickup module 20, so that the lens barrel is driven to move relative to the photosensitive element 210 by a magnetic force between the energized coil and the magnet, thereby achieving a focusing effect. In other embodiments, a similar driving mechanism may be provided to drive a portion of the lenses in the optical system 10 to move, thereby achieving an optical zoom effect.

Referring to fig. 12, some embodiments of the present application further provide an electronic device 30, and the camera module 20 is applied to the electronic device 30 to enable the electronic device 30 to have a camera function. Specifically, the electronic device 30 includes a fixing member 310, the camera module 20 is mounted on the fixing member 310, and the fixing member 310 may be a circuit board, a middle frame, or the like. The electronic device 30 may be, but is not limited to, a smart phone, a smart watch, an e-book reader, a vehicle-mounted camera device (such as a car recorder), a monitoring device, a medical device (such as an endoscope), a tablet computer, a biometric device (such as a fingerprint recognition device or a pupil recognition device), a PDA (personal digital Assistant), an unmanned aerial vehicle, and the like. Specifically, in one embodiment, the electronic device 30 is a smart phone, the smart phone includes a middle frame and a circuit board, the circuit board is disposed in the middle frame, the camera module 20 is installed in the middle frame of the smart phone, and the light sensing element 210 is electrically connected to the circuit board. The camera module 20 can be used as a front camera module or a rear camera module of the smart phone. By adopting the camera module 20 provided by the embodiment of the present application, the electronic device 30 will have good camera performance.

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 second lens element with negative refractive power;

a third lens element with positive refractive power;

a fourth lens element with refractive power;

a sixth lens element with negative refractive power;

and the optical system satisfies the following relationship:

-1.1＜Sag S10/CT5＜-0.5；

2. The optical system according to claim 1, characterized in that the following relation is satisfied:

1.2＜f123/CT123＜5.5；

wherein f123 is a combined focal length of the first lens element, the second lens element and the third lens element, and CT123 is a sum of thicknesses of the first lens element, the second lens element and the third lens element on an optical axis.

3. The optical system according to claim 1, characterized in that the following relation is satisfied:

6＜f1/CT1＜16；

wherein f1 is the effective focal length of the first lens, and CT1 is the thickness of the first lens on the optical axis.

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

-6＜f2/f＜-1；

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

5. The optical system according to claim 1, characterized in that the following relation is satisfied:

0.5＜f3/f＜3.2；

wherein f3 is an effective focal length of the third lens, and f is an effective focal length of the optical system.

6. The optical system of claim 1, wherein an image-side surface of the fourth lens is cemented to an object-side surface of the fifth lens, and the optical system satisfies the following relationship:

2＜f45/(CT5-CT4)＜6；

wherein f45 is a combined focal length of the fourth lens and the fifth lens, and CT4 is a thickness of the fourth lens on an optical axis.

7. The optical system according to claim 1, characterized in that the following relation is satisfied:

-4.2＜f6/CT6＜-1.2；

wherein f6 is an effective focal length of the sixth lens element, and CT6 is an optical thickness of the sixth lens element.

8. The optical system according to claim 1, characterized in that the following relation is satisfied:

0.1＜ExPD/f＜0.7；

wherein ExPD is the exit pupil diameter of the optical system, and f is the effective focal length of the optical system.

9. The optical system according to claim 1, characterized in that the following relation is satisfied:

0.2mm＜TTL/tan FOV＜2.2mm；

wherein, TTL is the total system length of the optical system, and FOV is the maximum field angle of the optical system.

10. The optical system according to claim 1, characterized in that the following relation is satisfied:

0.5＜Imgh/f＜2.2；

where Imgh is an image height corresponding to a maximum field angle of the optical system, and f is an effective focal length of the optical system.

11. The optical system of claim 1, wherein the second lens element has a convex object-side surface and a concave image-side surface; the object side surface of the third lens is a convex surface at the paraxial position, and the image side surface of the third lens is a convex surface or a concave surface at the paraxial position; the object side surface of the fourth lens is a concave surface at the paraxial position, and the image side surface of the fourth lens is a convex surface at the paraxial position; the object side surface of the fifth lens is a concave surface at the paraxial position, and the image side surface of the fifth lens is a convex surface at the paraxial position; the object side surface of the sixth lens element is convex or concave at the paraxial region, and the image side surface of the sixth lens element is concave at the paraxial region.

12. The optical system of claim 1, wherein at least one of the object-side surface and the image-side surface of the sixth lens has an inflection point.

13. An image pickup module comprising a photosensitive element and the optical system according to any one of claims 1 to 12, wherein the photosensitive element is disposed on an image side of the optical system.

14. An electronic device, comprising a fixing member and the camera module of claim 13, wherein the camera module is disposed on the fixing member.