CN113805309A

CN113805309A - Optical system, image capturing module and electronic equipment

Info

Publication number: CN113805309A
Application number: CN202111052147.1A
Authority: CN
Inventors: 华露; 刘彬彬; 杨健; 李明
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2021-09-08
Filing date: 2021-09-08
Publication date: 2021-12-17
Anticipated expiration: 2041-09-08
Also published as: CN113805309B

Abstract

The invention relates to an optical system, an image capturing module and an electronic device. The optical system includes: a first lens element with negative refractive power having a concave object-side surface at paraxial region; a second lens element with refractive power having a convex object-side surface and a concave image-side surface; a third lens element with positive refractive power having a convex object-side surface and a convex image-side surface; a fourth lens element with refractive power; a fifth lens element with positive refractive power having a convex image-side surface at paraxial region; a sixth lens element with negative refractive power having a convex object-side surface and a concave image-side surface; the optical system satisfies: f1/f6 is more than or equal to 1.4 and less than or equal to 2.5. The optical system can realize both wide-angle characteristics and high imaging quality.

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 gradual popularization of electronic devices such as smart phones and tablet computers, the requirements of consumers on the shooting performance of the camera lens are higher and higher. More and more electronic devices are provided with a camera lens with a wide-angle characteristic, so that the requirement of large-field shooting is met, and the camera lens can be suitable for more use scenes. Besides, the imaging quality is an important index for evaluating the shooting performance of the camera in the industry while having a wide-angle characteristic. However, the realization of the wide-angle characteristic is generally easy to cause the degradation of the imaging quality, and the realization of the wide-angle characteristic and the high imaging quality is difficult to be compatible with the current imaging lens.

Disclosure of Invention

Accordingly, it is desirable to provide an optical system, an image capturing module and an electronic device for solving the problem that the conventional imaging lens is difficult to achieve both wide-angle characteristics and high imaging quality.

An optical system includes, in order from an object side to an image side along an optical axis:

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

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

a third lens element with positive refractive power having a convex object-side surface and a convex image-side surface;

a fourth lens element with refractive power;

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

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

and the optical system satisfies the following conditional expression:

1.4≤f1/f6≤2.5；

wherein f1 is the effective focal length of the first lens, and f6 is the effective focal length of the sixth lens.

In the optical system, the first lens element has negative refractive power, and the object-side surface of the first lens element is concave at the paraxial region, which is beneficial for light rays with a large field of view to enter the optical system, thereby being beneficial to realizing the wide-angle characteristic. The object side surface of the second lens element is convex at the paraxial region, and the image side surface thereof is concave at the paraxial region, thereby facilitating the correction of aberration generated by the first lens element and improving the imaging quality of the optical system. The third lens element with positive refractive power has a convex object-side surface and a convex image-side surface at a paraxial region, and can effectively converge light, thereby shortening the total length of the optical system and realizing a miniaturized design. The fifth lens element with positive refractive power has a convex image-side surface at paraxial region, and is matched with the third lens element to further shorten the total length of the optical system. The positive refractive power of the fifth lens element is also beneficial to correcting aberrations such as field curvature of the optical system, and the imaging quality of the optical system is improved. The sixth lens element with negative refractive power is advantageous for balancing the positive spherical aberration of the optical system and for shortening the total length of the optical system. The image side surface of the sixth lens element is concave at the paraxial region, which is beneficial to increasing the optical back focus of the optical system and improving the assembly yield of the optical system. The optical system having the refractive power and the surface-type characteristics can realize wide-angle characteristics and a miniaturized design, and also has good imaging quality.

When the conditional expressions are met, the ratio of the effective focal lengths of the first lens and the sixth lens can be reasonably configured, so that aberration of the optical system can be corrected, imaging quality of the optical system can be improved, deflection of light rays in the optical system can be reduced, sensitivity of the first lens can be reduced, in addition, refractive power and surface type collocation of each lens of the optical system are matched, the field angle of the optical system can be enlarged, and wide-angle characteristics and high imaging quality can be achieved. When f1/f6 is greater than 2.5, the negative refractive power contributed by the first lens element is too weak to correct the aberration of the optical system, thereby reducing the imaging quality; when f1/f6 is less than 1.4, the negative refractive powers provided by the first lens element and the sixth lens element are similar, which is not favorable for shortening the total length of the system and inhibiting the generation of field curvature.

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

3mm≤TTL/tan(HFOV)≤3.4mm；

wherein, TTL is a distance on an optical axis from an object-side surface of the first lens element to an image plane of the optical system, that is, an optical total length of the optical system, and the HFOV is half of a maximum field angle of the optical system. When the conditional expressions are satisfied, the total optical length and the half field angle of the optical system can be reasonably configured, which is beneficial to expanding the field angle of the optical system, thereby satisfying the requirement of large-range shooting, and simultaneously is beneficial to shortening the total optical length of the optical system, thereby realizing wide-angle characteristics and miniaturization design.

1.5≤(f3+f5)/f≤3；

wherein f3 is an effective focal length of the third lens, f5 is an effective focal length of the fifth lens, and f is an effective focal length of the optical system. When the condition formula is met, the positive refractive power contribution amounts of the third lens and the fifth lens in the optical system can be reasonably distributed, so that the excessive refractive power of the single lens is avoided, the processing and forming of the third lens and the fifth lens are facilitated, the aberration of the optical system is also facilitated to be corrected, meanwhile, the third lens and the fifth lens can effectively converge light, the total length of the optical system is facilitated to be shortened, the structure of the optical system is more compact, and the imaging quality of the marginal field of view is also facilitated to be improved.

-1.5≤R32/f3≤-0.75；

wherein R32 is a radius of curvature of an image side surface of the third lens at an optical axis, and f3 is an effective focal length of the third lens. When the conditional expression is met, the ratio of the curvature radius of the image side surface of the third lens to the effective focal length can be reasonably configured, so that the high-grade spherical aberration of the optical system is balanced, the sensitivity of the optical system is reduced, and the imaging quality of the optical system is improved; meanwhile, the surface type of the third lens can be prevented from being too curved, so that the forming and assembling difficulty of the third lens is reduced.

8≤(R21+R22)/CT2≤15；

wherein R21 is a radius of curvature of an object-side surface of the second lens element at an optical axis, R22 is a radius of curvature of an image-side surface of the second lens element at the optical axis, and CT2 is a thickness of the second lens element at the optical axis, i.e., a center thickness of the second lens element. When the above conditional expressions are satisfied, the surface type and the central thickness of the second lens can be reasonably configured, so that the curvature radius of the object side surface and the image side surface of the second lens are matched, the off-axis aberration of the optical system is favorably corrected, the on-axis aberration of the optical system is balanced, the sensitivity of the optical system is reduced, the imaging quality of the optical system is improved, and in addition, the reasonable surface type curvature and the central thickness are also favorably processed and molded by the second lens. When the thickness of the center of the second lens is less than the lower limit of the conditional expression, the center thickness of the second lens is too large, and the surface shape of the second lens is too curved, so that the stability of the second lens is reduced, and the molding and the assembly of the second lens are not facilitated; when the upper limit of the conditional expression is exceeded, the surface shape of the second lens element is too gentle, the refractive power of the second lens element is insufficient, and the aberration of the optical system is not corrected favorably, so that the imaging quality of the optical system is not improved favorably.

2.6≤CT5/ET5≤3；

wherein CT5 is the thickness of the fifth lens element along the optical axis, and ET5 is the distance from the maximum effective aperture of the object-side surface of the fifth lens element to the maximum effective aperture of the image-side surface of the fifth lens element along the optical axis, i.e. the thickness of the edge of the fifth lens element. When the condition formula is satisfied, the ratio of the center thickness and the edge thickness of the fifth lens can be reasonably configured, and the field curvature and the distortion of the optical system can be favorably corrected, so that the imaging quality of the optical system is improved, and meanwhile, the phenomenon that the difference between the center thickness and the edge thickness is too large can be avoided, and the forming difficulty and the processing difficulty of the fifth lens are reduced. When the upper limit of the conditional expression is exceeded, the central thickness of the fifth lens is too large, the difference between the central thickness and the edge thickness is too large, the uniformity of the fifth lens is too low, the manufacturability of the fifth lens in molding and assembling cannot be ensured, and meanwhile, the risk of generating ghost images is increased; when the refractive power of the fifth lens element is lower than the lower limit of the conditional expression, the thickness of the edge of the fifth lens element is too large, which results in insufficient refractive power of the fifth lens element and is not favorable for correcting the aberration of the optical system, thereby being unfavorable for improving the imaging quality.

SD11/tan(HFOV)≤1.1mm；

wherein SD11 is half of the maximum effective aperture of the object-side surface of the first lens, and HFOV is half of the maximum field angle of the optical system. When the condition formula is met, the effective caliber of the first lens and the field angle of the optical system can be reasonably configured, the effective caliber of the first lens is reduced, the size and occupied volume of the optical system are reduced, the small head design of the optical system is realized, meanwhile, the optical system is provided with a large field angle, and the requirement of large-range shooting is met. When the upper limit of the above conditional expression is exceeded, the effective aperture of the first lens is too large, which is disadvantageous to the structural arrangement of the optical system and increases the risk of generating ghost images.

-3≤f5/(SAG51+SAG52)≤-1.5；

wherein f5 is an effective focal length of the fifth lens, SAG51 is a vector height of an object side surface of the fifth lens at a maximum effective aperture, namely, a distance from an intersection point of the object side surface of the fifth lens and an optical axis to the maximum effective aperture of the object side surface of the fifth lens in the optical axis direction, wherein the maximum effective aperture of the object side surface of the fifth lens is located on the image side of the intersection point of the object side surface and the optical axis, SAG51 is positive, the maximum effective aperture of the object side surface of the fifth lens is located on the object side surface of the intersection point of the object side surface and the optical axis, SAG51 is positive, SAG52 is a vector height of the image side surface of the fifth lens at a maximum effective aperture, namely, a distance from the intersection point of the image side surface of the fifth lens and the optical axis to the maximum effective aperture of the image side surface of the fifth lens in the optical axis direction, wherein the maximum effective aperture of the image side surface of the fifth lens is located on the image side of the intersection point of the image side surface and the optical axis, SAG52 is positive, the maximum effective aperture of the image side surface of the fifth lens is positioned on the object side of the intersection point of the image side surface and the optical axis, and SAG52 is negative. When the conditional expressions are met, the shape and the effective focal length of the fifth lens can be reasonably configured, so that the surface shape of the fifth lens cannot be excessively bent, the manufacturability of the fifth lens is improved, the risk of ghost images and stray light is reduced, meanwhile, the aberration of the optical system is favorably corrected, and the imaging quality of the optical system is improved.

-4.6％/mm≤Dmax/f≤-2％/mm；

where Dmax is the maximum distortion in all fields of view of the optical system, and f is the effective focal length of the optical system. When the condition formula is satisfied, the deformation degree of the actual imaging of the optical system is favorably weakened when the wide-angle characteristic is realized, so that the optical performance of the optical system is improved, and the realization of the wide-angle characteristic and high imaging quality is considered.

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. Adopt above-mentioned optical system among the getting for instance the module, can compromise wide angle characteristic and high imaging quality's realization, possess good imaging quality when satisfying the shooting demand on a large scale, also be favorable to realizing miniaturized design simultaneously.

An electronic device comprises a shell and the image capturing module, wherein the image capturing module is arranged on the shell. Adopt above-mentioned getting for instance module among the electronic equipment, can compromise wide angle characteristic and high imaging quality's realization, possess good imaging quality when satisfying the demand of shooing on a large scale, also be favorable to realizing the miniaturized design simultaneously.

Drawings

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

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

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

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

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

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

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

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

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

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

FIG. 11 is a schematic structural diagram of an optical system according to a sixth embodiment of the present application;

FIG. 12 is a longitudinal 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 along an optical axis 110, 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. Specifically, the first lens element L1 includes an object-side surface S1 and an image-side surface S2, the second lens element L2 includes an object-side surface S3 and an image-side surface S4, the third lens element L3 includes an object-side surface S5 and an image-side surface S6, the fourth lens element L4 includes an object-side surface S7 and an image-side surface S8, the fifth lens element L5 includes an object-side surface S9 and an image-side surface S10, and the sixth lens element L6 includes an object-side surface S11 and an image-side surface S12. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 are coaxially disposed, and an axis common to the lenses in the optical system 100 is an optical axis 110 of the optical system 100.

The first lens element L1 with negative refractive power has a concave object-side surface S1 at the paraxial region 110 of the first lens element L1, which is favorable for the light rays with large field of view to enter the optical system 100, thereby facilitating the realization of wide-angle characteristics. The second lens element L2 has refractive power. The object-side surface S3 of the second lens element L2 is convex at the paraxial region 110, and the image-side surface S4 is concave at the paraxial region 110, which is favorable for correcting the aberration generated by the first lens element L1 and improving the imaging quality of the optical system 100. The third lens element L3 with positive refractive power has a convex object-side surface S5 and image-side surface S6 of the third lens element L3 at a paraxial region 110, which can effectively converge light beams, thereby facilitating a reduction in the overall length of the optical system 100 and achieving a compact design. The fourth lens element L4 has refractive power. The fifth lens element L5 with positive refractive power has a convex image-side surface S10 at a paraxial region 110 of the fifth lens element L5, which cooperates with the third lens element L3 to further shorten the overall length of the optical system 100. The positive refractive power of the fifth lens element L5 is also beneficial to correct aberrations such as curvature of field of the optical system 100, so as to improve the imaging quality of the optical system 100. The sixth lens element L6 with negative refractive power is advantageous for balancing the positive spherical aberration of the optical system 100 and for shortening the total length of the optical system 100. The object-side surface S11 of the sixth lens element L6 is convex at the paraxial region 110. The image-side surface S12 of the sixth lens element L6 is concave at a position near the optical axis 110, which is beneficial to increasing the optical back focus of the optical system 100 and improving the assembly yield of the optical system 100. With the above-described refractive power and surface profile characteristics, the optical system 100 can achieve a wide-angle characteristic and a compact design, and can also have good imaging quality.

In some embodiments, both the object-side surface S11 and the image-side surface S12 of the sixth lens element L6 are aspheric, which is beneficial to correct spherical aberration of the optical system 100 and improve the imaging quality of the optical system 100. In some embodiments, the presence of the inflection point on one of the object-side surface S11 and the image-side surface S12 of the sixth lens element L6 is beneficial to reasonably distributing the refractive power in the vertical axis direction, so as to be beneficial to improving the aberration of the off-axis field, reducing the size of the diffuse spot, and improving the imaging quality of the optical system 100.

In addition, in some embodiments, the optical system 100 is provided with a stop STO, which may be disposed between the second lens L2 and the third lens L3. In some embodiments, the optical system 100 further includes an infrared cut filter L7 disposed on the image side of the sixth lens L6. The infrared cut filter L7 is used to filter the interference light and prevent the interference light from reaching the image plane of the optical system 100 to affect the normal image. Furthermore, the optical system 100 further includes an image plane S15 located on the image side of the sixth lens L6, the image plane S15 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, and the sixth lens L6 and can be imaged on the image plane S15.

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

In some embodiments, each lens in the optical system 100 may be made of glass or plastic. The lens made of plastic material can reduce the weight of the optical system 100 and the production cost, and the light and thin design of the optical system 100 can be realized by matching with the small size of the optical system 100. The glass lens provides the optical system 100 with excellent optical performance and high temperature resistance. It should be noted that the material of each lens in the optical system 100 may be any combination of glass and plastic, and is not necessarily both glass and plastic.

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, or the sixth lens L6 in some embodiments may also be greater than or equal to two, and a cemented lens may be formed between any two adjacent lenses, or may also be a non-cemented lens.

Further, in some embodiments, the optical system 100 satisfies the conditional expression: f1/f6 is more than or equal to 1.4 and less than or equal to 2.5; where f1 is the effective focal length of the first lens L1, and f6 is the effective focal length of the sixth lens L6. Specifically, f1/f6 may be: 1.406, 1.512, 1.587, 1.635, 1.732, 1.889, 1.902, 1.967, 2.025 or 2.277. When the above conditional expressions are satisfied, the ratio of the effective focal lengths of the first lens element L1 and the sixth lens element L6 can be configured reasonably, which is favorable for correcting the aberration of the optical system 100, improving the imaging quality of the optical system 100, and simultaneously being favorable for reducing the deflection of light in the optical system 100, thereby reducing the sensitivity of the first lens element L1, and in addition, matching the refractive power and the surface type collocation of each lens element of the optical system 100 is also favorable for expanding the field angle of the optical system 100, thereby taking into account the realization of wide-angle characteristics and high imaging quality. When f1/f6 > 2.5, the negative refractive power contributed by the first lens element L1 is too weak to correct the aberration of the optical system 100, thereby causing the image quality to be degraded; when f1/f6 is less than 1.4, the negative refractive powers provided by the first lens element L1 and the sixth lens element L6 are similar, which is not favorable for shortening the total length of the system and inhibiting the generation of field curvature.

In some embodiments, the optical system 100 satisfies the conditional expression: TTL/tan (HFOV) is less than or equal to 3mm and less than or equal to 3.4 mm; wherein, TTL is a distance on the optical axis 110 from the object-side surface S1 of the first lens element L1 to the image plane of the optical system 100, and HFOV is half of the maximum field angle of the optical system 100. Specifically, TTL/tan (hfov) may be: 3.021, 3.035, 3.047, 3.110, 3.128, 3.178, 3.255, 3.287, 3.299 or 3.322, in mm. When the above conditional expressions are satisfied, the total optical length and the half field angle of the optical system 100 can be reasonably arranged, which is advantageous for expanding the field angle of the optical system 100, thereby satisfying the demand for large-range shooting, and is also advantageous for shortening the total length of the optical system 100, thereby achieving both the wide-angle characteristic and the miniaturization design.

It should be noted that in some embodiments, the optical system 100 may match a photosensitive element having a rectangular photosensitive surface, and the imaging surface of the optical system 100 coincides with the photosensitive surface of the photosensitive element. At this time, the effective pixel region on the imaging plane of the optical system 100 has a horizontal direction and a diagonal direction, and the HFOV can be understood as half of the maximum field angle of the optical system 100 in the diagonal direction.

In some embodiments, the optical system 100 satisfies the conditional expression: (f3+ f5)/f is more than or equal to 1.5 and less than or equal to 3; where f3 is the effective focal length of the third lens L3, f5 is the effective focal length of the fifth lens L5, and f is the effective focal length of the optical system 100. Specifically, (f3+ f5)/f may be: 1.997, 2.021, 2.074, 2.128, 2.167, 2.225, 2.341, 2.387, 2.406, or 2.603. When the above conditional expressions are satisfied, the positive refractive power contributions of the third lens element L3 and the fifth lens element L5 in the optical system 100 can be reasonably distributed, so that the excessive refractive power of a single lens element is avoided, which is beneficial to the processing and molding of the third lens element L3 and the fifth lens element L5 and also beneficial to the correction of the aberration of the optical system 100, and meanwhile, the third lens element L3 and the fifth lens element L5 can effectively converge light, which is beneficial to the shortening of the total length of the optical system 100, so that the optical system 100 has a more compact structure, and is also beneficial to the improvement of the imaging quality of the marginal field.

In some embodiments, the optical system 100 satisfies the conditional expression: r32/f3 is not less than 1.5 and not more than-0.75; wherein R32 is the radius of curvature of the image-side surface S6 of the third lens element L3 at the optical axis 110, and f3 is the effective focal length of the third lens element L3. Specifically, R32/f3 may be: -1.336, -1.297, -1.255, -1.156, -1.096, -0.973, -0.937, -0.884, -0.855, or-0.832. When the conditional expressions are satisfied, the ratio of the curvature radius of the image-side surface S6 of the third lens L3 to the effective focal length can be configured reasonably, which is beneficial to balancing the high-level spherical aberration of the optical system 100, thereby reducing the sensitivity of the optical system 100 and further improving the imaging quality of the optical system 100; meanwhile, the excessive bending of the surface shape of the third lens L3 can be avoided, so that the difficulty in molding and assembling the third lens L3 is reduced.

In some embodiments, the optical system 100 satisfies the conditional expression: (R21+ R22)/CT2 is not more than 8 and not more than 15; wherein R21 is a radius of curvature of the object-side surface S3 of the second lens element L2 along the optical axis 110, R22 is a radius of curvature of the image-side surface S4 of the second lens element L2 along the optical axis 110, and CT2 is a thickness of the second lens element L2 along the optical axis 110. Specifically, (R21+ R22)/CT2 may be: 8.245, 8.754, 9.328, 9.697, 10.251, 11.335, 12.751, 12.965, 13.052 or 14.626. When the conditional expressions are satisfied, the surface shape and the center thickness of the second lens L2 can be reasonably configured, so that the curvature radii of the object side surface S3 and the image side surface S4 of the second lens L2 are matched, which is favorable for correcting the off-axis aberration of the optical system 100 and balancing the on-axis aberration of the optical system 100, thereby reducing the sensitivity of the optical system 100 and improving the imaging quality of the optical system 100, and in addition, the configuration of the reasonable surface shape curvature and the center thickness is also favorable for processing and molding the second lens L2. When the lower limit of the above conditional expression is exceeded, the center thickness of the second lens L2 becomes too large, and the surface shape of the second lens L2 becomes too curved, so that the stability of the second lens L2 is lowered, which is disadvantageous to the molding and assembling of the second lens L2; when the upper limit of the above conditional expression is exceeded, the surface shape of the second lens element L2 is too gentle, and the refractive power of the second lens element L2 is insufficient, which is not favorable for correcting the aberration of the optical system 100, and is not favorable for improving the imaging quality of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: CT5/ET5 is more than or equal to 2.6 and less than or equal to 3; CT5 is the thickness of the fifth lens element L5 along the optical axis 110, and ET5 is the distance from the maximum effective aperture of the object-side surface S9 of the fifth lens element L5 to the maximum effective aperture of the image-side surface S10 of the fifth lens element L5 along the optical axis 110, i.e., the edge thickness of the fifth lens element L5. Specifically, CT5/ET5 may be: 2.615, 2.674, 2.711, 2.735, 2.776, 2.798, 2.805, 2.853, 2.914 or 2.997. When the above conditional expressions are satisfied, the ratio of the center thickness and the edge thickness of the fifth lens L5 can be reasonably configured, which is beneficial to correcting the field curvature and distortion of the optical system 100, thereby improving the imaging quality of the optical system 100, and simultaneously avoiding the excessive difference between the center thickness and the edge thickness, thereby reducing the increase of the molding and processing difficulty of the fifth lens L5. When the upper limit of the conditional expression is exceeded, the central thickness of the fifth lens L5 is too large, the difference between the central thickness and the edge thickness is too large, and the uniformity of the fifth lens L5 is too low, so that the manufacturability of molding and assembling the fifth lens L5 cannot be ensured, and meanwhile, the risk of generating ghost images is increased; the fifth lens element L5 has positive refractive power, and when the refractive power is lower than the lower limit of the conditional expression, the thickness of the edge of the fifth lens element L5 is too large, which results in insufficient refractive power of the fifth lens element L5, which is not favorable for correcting the aberration of the optical system 100, and is not favorable for improving the image quality.

In some embodiments, the optical system 100 satisfies the conditional expression: SD11/tan (HFOV) is less than or equal to 1.1 mm; SD11 is half the maximum effective aperture of the object-side surface S1 of the first lens L1, and HFOV is half the maximum angle of view of the optical system 100. Specifically, SD11/tan (hfov) may be: 0.873, 0.885, 0.892, 0.911, 0.923, 0.947, 0.967, 0.993, 1.002 or 1.017, the numerical units being mm. When the above conditional expressions are satisfied, the effective aperture of the first lens L1 and the angle of view of the optical system 100 can be reasonably arranged, which is advantageous for reducing the effective aperture of the first lens L1, thereby being advantageous for reducing the size and occupied volume of the optical system 100, realizing a small head design of the optical system 100, and simultaneously being advantageous for the optical system 100 to have a large angle of view, thereby satisfying the demand for large-scale shooting. When the upper limit of the above conditional expression is exceeded, the effective aperture of the first lens L1 becomes too large, which is disadvantageous for the structural arrangement of the optical system 100 and increases the risk of ghost image generation.

In some embodiments, the optical system 100 satisfies the conditional expression: f5/(SAG51+ SAG52) is more than or equal to 3 and less than or equal to-1.5; where f5 is the effective focal length of the fifth lens L5, SAG51 is the rise of the object-side surface S9 of the fifth lens L5 at the maximum effective aperture, and SAG52 is the rise of the image-side surface S10 of the fifth lens L5 at the maximum effective aperture. Specifically, f5/(SAG51+ SAG52) may be: -2.534, -2.487, -2.396, -2.351, -2.254, -2.169, -2.055, -1.957, -1.882 or-1.840. When the conditional expressions are satisfied, the shape and the effective focal length of the fifth lens L5 can be reasonably configured, so that the surface shape of the fifth lens L5 is not too curved, the manufacturability of the fifth lens L5 processing is improved, the risk of ghost images and stray light is reduced, meanwhile, the aberration of the optical system 100 is favorably corrected, and the imaging quality of the optical system 100 is improved.

In some embodiments, the optical system 100 satisfies the conditional expression: dmax/f is less than or equal to minus 2%/mm and less than or equal to minus 4.6%/mm; where Dmax is the maximum distortion in all fields of view of the optical system 100 and f is the effective focal length of the optical system 100. Specifically, Dmax/f may be: -4.600, -4.512, -4.210, -3.845, -3.671, -3.412, -3.164, -2.874, -2.631 or-2.221 in%/mm. When the above conditional expressions are satisfied, it is beneficial to weaken the deformation degree of the optical system 100 when the wide-angle characteristic is realized, so as to improve the optical performance of the optical system 100, and further consider the realization of the wide-angle characteristic and the high imaging quality.

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

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

First embodiment

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

The object-side surface S1 of the first lens element L1 is concave at a paraxial region 110 and concave at a peripheral region;

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

the object-side surface S3 of the second lens element L2 is convex at a paraxial region 110 and convex at a peripheral region;

the image-side surface S4 of the second lens element L2 is concave at a paraxial region 110 and concave at a peripheral region;

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

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

the object-side surface S7 of the fourth lens element L4 is concave at a paraxial region 110 and concave at a peripheral region;

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

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

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

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

the image-side surface S12 of the sixth lens element L6 is concave at the paraxial region 110 and concave at the periphery.

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, and the sixth lens L6 are aspheric.

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

Further, the optical system 100 satisfies the conditional expression: f1/f6 ═ 1.406; where f1 is the effective focal length of the first lens L1, and f6 is the effective focal length of the sixth lens L6. When the above conditional expressions are satisfied, the ratio of the effective focal lengths of the first lens element L1 and the sixth lens element L6 can be configured reasonably, which is favorable for correcting the aberration of the optical system 100, improving the imaging quality of the optical system 100, and simultaneously being favorable for reducing the deflection of light in the optical system 100, thereby reducing the sensitivity of the first lens element L1, and in addition, matching the refractive power and the surface type collocation of each lens element of the optical system 100 is also favorable for expanding the field angle of the optical system 100, thereby taking into account the realization of wide-angle characteristics and high imaging quality.

The optical system 100 satisfies the conditional expression: TTL/tan (hfov) ═ 3.049 mm; wherein, TTL is a distance on the optical axis 110 from the object-side surface S1 of the first lens element L1 to the image plane of the optical system 100, and HFOV is half of the maximum field angle of the optical system 100. When the above conditional expressions are satisfied, the total optical length and the half field angle of the optical system 100 can be reasonably arranged, which is advantageous for expanding the field angle of the optical system 100, thereby satisfying the demand for large-range shooting, and is also advantageous for shortening the total length of the optical system 100, thereby achieving both the wide-angle characteristic and the miniaturization design.

The optical system 100 satisfies the conditional expression: (f3+ f5)/f ═ 2.257; where f3 is the effective focal length of the third lens L3, f5 is the effective focal length of the fifth lens L5, and f is the effective focal length of the optical system 100. When the above conditional expressions are satisfied, the positive refractive power contributions of the third lens element L3 and the fifth lens element L5 in the optical system 100 can be reasonably distributed, so that the excessive refractive power of a single lens element is avoided, which is beneficial to the processing and molding of the third lens element L3 and the fifth lens element L5 and also beneficial to the correction of the aberration of the optical system 100, and meanwhile, the third lens element L3 and the fifth lens element L5 can effectively converge light, which is beneficial to the shortening of the total length of the optical system 100, so that the optical system 100 has a more compact structure, and is also beneficial to the improvement of the imaging quality of the marginal field.

The optical system 100 satisfies the conditional expression: r32/f3 ═ -0.972; wherein R32 is the radius of curvature of the image-side surface S6 of the third lens element L3 at the optical axis 110, and f3 is the effective focal length of the third lens element L3. When the conditional expressions are satisfied, the ratio of the curvature radius of the image-side surface S6 of the third lens L3 to the effective focal length can be configured reasonably, which is beneficial to balancing the high-level spherical aberration of the optical system 100, thereby reducing the sensitivity of the optical system 100 and further improving the imaging quality of the optical system 100; meanwhile, the excessive bending of the surface shape of the third lens L3 can be avoided, so that the difficulty in molding and assembling the third lens L3 is reduced.

The optical system 100 satisfies the conditional expression: (R21+ R22)/CT2 ═ 14.626; wherein R21 is a radius of curvature of the object-side surface S3 of the second lens element L2 along the optical axis 110, R22 is a radius of curvature of the image-side surface S4 of the second lens element L2 along the optical axis 110, and CT2 is a thickness of the second lens element L2 along the optical axis 110. When the conditional expressions are satisfied, the surface shape and the center thickness of the second lens L2 can be reasonably configured, so that the curvature radii of the object side surface S3 and the image side surface S4 of the second lens L2 are matched, which is favorable for correcting the off-axis aberration of the optical system 100 and balancing the on-axis aberration of the optical system 100, thereby reducing the sensitivity of the optical system 100 and improving the imaging quality of the optical system 100, and in addition, the configuration of the reasonable surface shape curvature and the center thickness is also favorable for processing and molding the second lens L2.

The optical system 100 satisfies the conditional expression: CT5/ET5 ═ 2.997; CT5 is the thickness of the fifth lens element L5 along the optical axis 110, and ET5 is the distance from the maximum effective aperture of the object-side surface S9 of the fifth lens element L5 to the maximum effective aperture of the image-side surface S10 of the fifth lens element L5 along the optical axis 110. When the above conditional expressions are satisfied, the ratio of the center thickness and the edge thickness of the fifth lens L5 can be reasonably configured, which is beneficial to correcting the field curvature and distortion of the optical system 100, thereby improving the imaging quality of the optical system 100, and simultaneously avoiding the excessive difference between the center thickness and the edge thickness, thereby reducing the increase of the molding and processing difficulty of the fifth lens L5.

The optical system 100 satisfies the conditional expression: SD11/tan (hfov) ═ 0.873 mm; SD11 is half the maximum effective aperture of the object-side surface S1 of the first lens L1, and HFOV is half the maximum angle of view of the optical system 100. When the above conditional expressions are satisfied, the effective aperture of the first lens L1 and the angle of view of the optical system 100 can be reasonably arranged, which is advantageous for reducing the effective aperture of the first lens L1, thereby being advantageous for reducing the size and occupied volume of the optical system 100, realizing a small head design of the optical system 100, and simultaneously being advantageous for the optical system 100 to have a large angle of view, thereby satisfying the demand for large-scale shooting.

The optical system 100 satisfies the conditional expression: f5/(SAG51+ SAG52) — 2.534; where f5 is the effective focal length of the fifth lens L5, SAG51 is the rise of the object-side surface S9 of the fifth lens L5 at the maximum effective aperture, and SAG52 is the rise of the image-side surface S10 of the fifth lens L5 at the maximum effective aperture. When the conditional expressions are satisfied, the shape and the effective focal length of the fifth lens L5 can be reasonably configured, so that the surface shape of the fifth lens L5 is not too curved, the manufacturability of the fifth lens L5 processing is improved, the risk of ghost images and stray light is reduced, meanwhile, the aberration of the optical system 100 is favorably corrected, and the imaging quality of the optical system 100 is improved.

The optical system 100 satisfies the conditional expression: dmax/f is-4.462%/mm; where Dmax is the maximum distortion in all fields of view of the optical system 100 and f is the effective focal length of the optical system 100. When the above conditional expressions are satisfied, it is beneficial to weaken the deformation degree of the optical system 100 when the wide-angle characteristic is realized, so as to improve the optical performance of the optical system 100, and further consider the realization of the wide-angle characteristic and the high imaging quality.

In addition, the parameters of the optical system 100 are given in table 1. Among them, the image plane S15 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 S15 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 or image-side surface at the optical axis 110 for the corresponding surface number. Surface numbers S1 and S2 denote an object-side surface S1 and an image-side surface S2 of the first lens L1, respectively, that is, in the same lens, a surface with a smaller surface number is an object-side surface, and a surface with a larger surface number is an image-side surface. The first numerical value in the "thickness" parameter column of the first lens element L1 is the thickness of the lens element along the optical axis 110, and the second numerical value is the distance between the image-side surface and the rear surface of the lens element along the image-side direction along the optical axis 110.

Note that, in this embodiment and the following embodiments, the optical system 100 may not be provided with the infrared cut filter L7, but the distance from the image side surface S12 to the image surface S15 of the sixth lens L6 is kept constant at this time.

In the first embodiment, the effective focal length f of the optical system 100 is 2.159mm, the f-number FNO is 2.2, the maximum field angle FOV is 124.534deg, and the total optical length TTL is 5.8 mm. It can be seen that the optical system 100 can achieve both wide-angle characteristics and high imaging quality, can satisfy the requirement for large-range shooting, and can also achieve good imaging quality, and at the same time, the optical system 100 also has a large aperture characteristic, has sufficient light flux, and can also achieve good imaging quality in a low-light environment, and in addition, the optical system 100 can also achieve a miniaturized design, and thus can be applied to portable electronic devices.

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

TABLE 1

Further, aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are given by table 2. Wherein, the surface numbers from S1 to S12 represent the image side or the object side S1 to S12, 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:

where Z is the distance from the corresponding point on the aspheric surface to the plane tangent to the surface vertex, r is the distance from the corresponding point on the aspheric surface to the optical axis 110, c is the curvature of the aspheric surface vertex, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th high order term in the aspheric surface profile formula.

TABLE 2

Number of noodles

S1

S2

S3

S4

S5

S6

K

-4.547E+01

1.894E+01

-6.825E+00

1.079E-02

-8.165E+00

3.628E+00

A4

3.954E-01

8.283E-01

2.133E-01

8.648E-02

1.804E-02

-3.653E-01

A6

-5.651E-01

-1.264E+00

-6.820E-01

-3.603E-01

1.368E+00

-3.271E-02

A8

6.920E-01

1.858E+00

2.659E+00

3.043E+00

-2.358E+01

7.256E-01

A10

-6.445E-01

-1.012E+00

-8.322E+00

-1.734E+01

2.342E+02

-8.973E-01

A12

4.263E-01

-3.019E+00

1.758E+01

6.478E+01

-1.435E+03

-1.424E+01

A14

-1.906E-01

8.132E+00

-2.410E+01

-1.483E+02

5.464E+03

7.046E+01

A16

5.424E-02

-8.982E+00

2.038E+01

1.984E+02

-1.259E+04

-1.443E+02

A18

-8.819E-03

4.813E+00

-9.561E+00

-1.389E+02

1.609E+04

1.407E+02

A20

6.205E-04

-1.009E+00

1.906E+00

3.825E+01

-8.739E+03

-5.391E+01

Number of noodles

S7

S8

S9

S10

S11

S12

K

-9.700E+01

-3.697E+01

-9.899E+01

-3.008E+00

5.491E-01

-4.459E+00

A4

-5.636E-01

-1.773E-01

7.951E-03

-1.452E-02

-1.507E-01

-8.691E-02

A6

1.212E+00

3.867E-02

-1.087E-01

-8.987E-02

5.005E-03

3.175E-02

A8

-1.054E+01

2.952E-01

2.233E-01

1.387E-01

1.733E-02

-7.677E-03

A10

6.015E+01

-3.872E-01

-1.943E-01

-1.342E-01

-3.599E-04

1.090E-03

A12

-2.114E+02

-1.430E-01

8.330E-02

1.121E-01

-5.320E-03

-6.285E-05

A14

4.556E+02

8.523E-01

-1.090E-02

-5.991E-02

2.519E-03

-7.845E-06

A16

-5.873E+02

-9.325E-01

-4.969E-03

1.800E-02

-5.246E-04

1.975E-06

A18

4.134E+02

4.586E-01

2.083E-03

-2.804E-03

5.346E-05

-1.672E-07

A20

-1.214E+02

-8.702E-02

-2.253E-04

1.772E-04

-2.187E-06

5.430E-09

Fig. 2 includes a Longitudinal Spherical Aberration diagram (Longitudinal Spherical Aberration) of the optical system 100, in which the Longitudinal Spherical Aberration curve represents the deviation of the converging focus of the light rays with different wavelengths after passing through the lens, the ordinate represents the Normalized Pupil coordinate (Normalized Pupil coordiator) from the Pupil center to the Pupil edge, and the abscissa represents the focus deviation, i.e., the distance (in mm) from the image plane to the intersection of the light rays and the optical axis 110. It can be known from the longitudinal spherical aberration diagram that the convergent focus deviation degrees of the light rays with different wavelengths in the first embodiment tend to be consistent, and the diffuse speckles or color halos in the imaging picture are effectively inhibited. Fig. 2 also includes an astigmatism graph (ASTIGMATIC FIELD CURVES) of the optical system 100, in which the abscissa represents the focus offset and the ordinate represents the image height in mm, and the S-curve and the T-curve in the astigmatism graph represent sagittal curvature at 555nm and meridional curvature at 555nm, respectively. As can be seen from the figure, the curvature of field of the optical system 100 is small, the curvature of field and astigmatism of each field are well corrected, and the center and the edge of the field have clear images. Fig. 2 further includes a DISTORTION plot (distorrion) of the optical system 100, where the DISTORTION plot represents DISTORTION magnitude values corresponding to different angles of view, where the abscissa represents DISTORTION value in mm and the ordinate represents image height in mm. As can be seen from the figure, the image distortion caused by the main beam is small, and the imaging quality of the system is excellent.

Second embodiment

Referring to fig. 3 and 4, fig. 3 is a schematic structural diagram of 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 first lens element L1 with negative refractive power, a second lens element L2 with positive refractive power, a stop STO, 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. 4 is a graph of longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the second embodiment, which is shown from left to right.

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

the object-side surface S7 of the fourth lens element L4 is convex at a paraxial region 110 and concave at a peripheral region;

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

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

TABLE 3

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

TABLE 4

Number of noodles

S1

S2

S3

S4

S5

S6

K

-5.051E+01

1.314E+01

-9.776E+00

-2.313E+00

-8.993E+00

5.827E+00

A4

3.345E-01

7.591E-01

1.505E-01

5.480E-02

1.703E-02

-3.935E-01

A6

-4.372E-01

-1.445E+00

-3.533E-01

7.494E-02

1.345E+00

-5.478E-01

A8

4.669E-01

3.316E+00

9.474E-01

-1.543E+00

-2.218E+01

1.616E+00

A10

-3.712E-01

-6.522E+00

-2.332E+00

1.365E+01

2.049E+02

6.089E+00

A12

2.088E-01

9.483E+00

4.046E+00

-6.691E+01

-1.163E+03

-4.957E+01

A14

-7.952E-02

-9.364E+00

-4.597E+00

2.028E+02

4.095E+03

1.457E+02

A16

1.935E-02

5.838E+00

3.293E+00

-3.654E+02

-8.738E+03

-2.290E+02

A18

-2.704E-03

-2.056E+00

-1.340E+00

3.580E+02

1.034E+04

1.889E+02

A20

1.640E-04

3.093E-01

2.367E-01

-1.452E+02

-5.218E+03

-6.429E+01

Number of noodles

S7

S8

S9

S10

S11

S12

K

-9.700E+01

-9.049E+00

-9.899E+01

-2.935E+00

3.554E-01

-4.777E+00

A4

-3.344E-01

1.747E-01

5.106E-02

2.473E-02

-1.286E-01

-7.423E-02

A6

-5.727E-01

-1.173E+00

-4.432E-02

-2.435E-01

-2.422E-02

3.808E-02

A8

-4.328E+00

2.259E+00

1.025E-01

4.480E-01

9.181E-02

-1.587E-02

A10

3.717E+01

-1.939E+00

-1.658E-01

-4.451E-01

-8.144E-02

4.773E-03

A12

-1.311E+02

-7.523E-02

1.718E-01

2.977E-01

4.005E-02

-1.011E-03

A14

2.695E+02

1.920E+00

-1.121E-01

-1.305E-01

-1.196E-02

1.452E-04

A16

-3.316E+02

-1.959E+00

4.383E-02

3.491E-02

2.136E-03

-1.338E-05

A18

2.245E+02

8.931E-01

-9.381E-03

-5.121E-03

-2.081E-04

7.087E-07

A20

-6.394E+01

-1.614E-01

8.443E-04

3.150E-04

8.465E-06

-1.622E-08

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

f1/f6	1.541	CT5/ET5	2.981
				TTL/tan(HFOV)(mm)	3.021	SD11/tan(HFOV)(mm)	0.906
(f3+f5)/f	2.310	f5/(SAG51+SAG52)	-2.470
				R32/f3	-1.040	Dmax/f(/mm)	-4.478
(R21+R22)/CT2	10.564

in addition, as can be seen from the aberration diagram in fig. 4, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are well controlled, so that the optical system 100 of this embodiment has good imaging quality.

Third embodiment

Referring to fig. 5 and 6, fig. 5 is a schematic structural diagram of the optical system 100 in the third embodiment, in which the optical system 100 includes, in order from an object side to an image side, a first lens element L1 with negative refractive power, a second lens element L2 with positive refractive power, a stop STO, 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 is a graph of longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the third embodiment, from left to right.

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

the object-side surface S11 of the sixth lens element L6 is convex at a paraxial region 110 and convex at a peripheral region;

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

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

TABLE 5

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

TABLE 6

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

f1/f6	1.459	CT5/ET5	2.924
				TTL/tan(HFOV)(mm)	3.268	SD11/tan(HFOV)(mm)	0.955
(f3+f5)/f	2.256	f5/(SAG51+SAG52)	-2.221
				R32/f3	-1.074	Dmax/f(/mm)	-3.476
(R21+R22)/CT2	10.914

in addition, as can be seen from the aberration diagram in fig. 6, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are well controlled, so that the optical system 100 of this embodiment has good imaging quality.

Fourth embodiment

Referring to fig. 7 and 8, fig. 7 is a schematic structural diagram of the optical system 100 in the fourth embodiment, in which the optical system 100 includes, in order from an object side to an image side, a first lens element L1 with negative refractive power, a second lens element L2 with negative refractive power, a stop STO, 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. 8 is a graph of longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the fourth embodiment, which is shown from left to right.

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

the object-side surface S7 of the fourth lens element L4 is concave at a paraxial region 110 and convex at a peripheral region;

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

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

TABLE 7

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

TABLE 8

f1/f6	2.277	CT5/ET5	2.615
				TTL/tan(HFOV)(mm)	3.073	SD11/tan(HFOV)(mm)	0.911
(f3+f5)/f	1.997	f5/(SAG51+SAG52)	-2.478
				R32/f3	-0.832	Dmax/f(/mm)	-4.600
(R21+R22)/CT2	12.939

in addition, as can be seen from the aberration diagram in fig. 8, the longitudinal spherical aberration, astigmatism, and distortion of the optical system 100 are well controlled, so that the optical system 100 of this embodiment has good imaging quality.

Fifth embodiment

Referring to fig. 9 and 10, fig. 9 is a schematic structural diagram of the optical system 100 in the fifth embodiment, in which the optical system 100 includes, in order from an object side to an image side, a first lens element L1 with negative refractive power, a second lens element L2 with positive refractive power, a stop STO, 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 is a graph showing the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the fifth embodiment 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

Number of noodles

S1

S2

S3

S4

S5

S6

K

-6.297E+01

1.594E+01

-3.950E+00

-9.886E-01

-8.208E+00

-3.509E+01

A4

3.086E-01

7.727E-01

1.759E-01

4.118E-02

9.322E-03

-2.614E-01

A6

-3.467E-01

-1.277E+00

-4.008E-01

5.899E-01

8.913E-01

-1.156E-01

A8

3.354E-01

2.440E+00

1.610E+00

-6.357E+00

-1.095E+01

-1.364E+00

A10

-2.543E-01

-3.569E+00

-5.284E+00

3.975E+01

7.792E+01

1.035E+01

A12

1.423E-01

3.397E+00

1.118E+01

-1.518E+02

-3.477E+02

-3.639E+01

A14

-5.540E-02

-1.747E+00

-1.489E+01

3.575E+02

9.703E+02

7.283E+01

A16

1.400E-02

1.885E-01

1.196E+01

-5.054E+02

-1.642E+03

-8.427E+01

A18

-2.041E-03

2.098E-01

-5.248E+00

3.941E+02

1.536E+03

5.251E+01

A20

1.290E-04

-6.686E-02

9.666E-01

-1.296E+02

-6.100E+02

-1.370E+01

Number of noodles

S7

S8

S9

S10

S11

S12

K

-9.700E+01

1.150E+01

-5.516E+01

-2.526E+00

3.389E-01

-5.067E+00

A4

-2.378E-01

2.061E-02

6.883E-02

1.446E-01

-1.534E-01

-7.146E-02

A6

1.630E-01

-5.799E-01

-5.353E-01

-5.749E-01

-2.456E-02

2.371E-02

A8

-2.480E+00

1.703E+00

1.539E+00

1.050E+00

1.214E-01

-4.990E-03

A10

9.273E+00

-3.182E+00

-2.443E+00

-1.256E+00

-1.378E-01

8.778E-05

A12

-2.068E+01

4.079E+00

2.449E+00

1.001E+00

9.093E-02

3.578E-04

A14

2.913E+01

-3.491E+00

-1.609E+00

-5.101E-01

-3.670E-02

-1.343E-04

A16

-2.452E+01

1.904E+00

6.734E-01

1.573E-01

8.695E-03

2.346E-05

A18

1.105E+01

-5.972E-01

-1.625E-01

-2.655E-02

-1.099E-03

-2.014E-06

A20

-2.017E+00

8.171E-02

1.708E-02

1.871E-03

5.696E-05

6.806E-08

in addition, as can be seen from the aberration diagram in fig. 10, the longitudinal spherical aberration, astigmatism, and distortion of the optical system 100 are well controlled, so that the optical system 100 of this embodiment has good imaging quality.

Sixth embodiment

Referring to fig. 11 and 12, fig. 11 is a schematic structural diagram of 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 first lens element L1 with negative refractive power, a second lens element L2 with positive refractive power, a stop STO, 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. 12 is a graph showing longitudinal 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

Number of noodles

S1

S2

S3

S4

S5

S6

K

-4.168E+01

1.725E+01

-4.694E+00

-1.616E+00

-7.439E+00

-4.046E+01

A4

2.928E-01

6.486E-01

2.180E-01

5.224E-02

1.738E-02

-2.814E-01

A6

-3.264E-01

-7.858E-01

-4.846E-01

3.538E-01

9.110E-01

-3.444E-01

A8

2.882E-01

8.355E-01

1.314E+00

-4.002E+00

-1.215E+01

1.353E+00

A10

-1.858E-01

-6.823E-01

-3.272E+00

2.486E+01

9.418E+01

-2.980E+00

A12

8.457E-02

4.443E-01

5.682E+00

-9.749E+01

-4.592E+02

-1.727E+00

A14

-2.596E-02

-2.713E-01

-6.847E+00

2.440E+02

1.403E+03

2.361E+01

A16

4.977E-03

8.711E-02

5.464E+00

-3.750E+02

-2.608E+03

-5.169E+01

A18

-5.072E-04

2.378E-02

-2.524E+00

3.230E+02

2.689E+03

4.998E+01

A20

1.724E-05

-1.631E-02

5.067E-01

-1.187E+02

-1.182E+03

-1.891E+01

Number of noodles

S7

S8

S9

S10

S11

S12

K

-9.700E+01

3.399E+01

-9.207E+01

-2.390E+00

1.352E-01

-4.675E+00

A4

-2.405E-01

6.660E-03

6.492E-02

1.753E-01

-1.441E-01

-8.389E-02

A6

-2.470E-01

-5.193E-01

-3.913E-01

-7.184E-01

-4.252E-02

4.440E-02

A8

-1.579E-01

1.512E+00

9.446E-01

1.326E+00

1.438E-01

-2.086E-02

A10

2.476E+00

-2.770E+00

-1.226E+00

-1.569E+00

-1.514E-01

6.851E-03

A12

-9.863E+00

3.597E+00

1.023E+00

1.210E+00

9.125E-02

-1.394E-03

A14

2.098E+01

-3.237E+00

-6.056E-01

-5.850E-01

-3.313E-02

1.521E-04

A16

-2.499E+01

1.905E+00

2.580E-01

1.682E-01

7.046E-03

-5.779E-06

A18

1.567E+01

-6.537E-01

-7.001E-02

-2.581E-02

-8.020E-04

-3.066E-07

A20

-4.018E+00

9.827E-02

8.654E-03

1.585E-03

3.758E-05

2.482E-08

f1/f6	1.753	CT5/ET5	2.946
				TTL/tan(HFOV)(mm)	3.061	SD11/tan(HFOV)(mm)	0.934
(f3+f5)/f	2.338	f5/(SAG51+SAG52)	-1.863
				R32/f3	-1.147	Dmax/f(/mm)	-3.435
(R21+R22)/CT2	8.380

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

Referring to fig. 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 S15 of the optical system 100. The image capturing module 200 may further include an ir-cut filter L7, wherein the ir-cut filter L7 is disposed between the image side S12 and the image plane S15 of the sixth lens element L6. Specifically, the photosensitive element 210 may be a Charge Coupled Device (CCD) or a Complementary Metal-Oxide Semiconductor (CMOS) Device. Adopt above-mentioned optical system 100 in getting for instance module 200, can compromise wide-angle characteristic and high imaging quality's realization, possess good imaging quality when satisfying the shooting demand on a large scale, also be favorable to realizing miniaturized design simultaneously to be favorable to the application in portable electronic equipment.

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. When the electronic device 300 is a smartphone, the housing 310 may be a middle frame of the electronic device 300. Adopt above-mentioned getting for instance module 200 in electronic equipment 300, can compromise wide angle characteristic and high imaging quality's realization, possess good imaging quality when satisfying the shooting demand on a large scale, also be favorable to realizing the miniaturized design simultaneously.

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 along an optical axis:

a fourth lens element with refractive power;

and the optical system satisfies the following conditional expression:

1.4≤f1/f6≤2.5；

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

3mm≤TTL/tan(HFOV)≤3.4mm；

wherein, TTL is a distance on an optical axis from an object-side surface of the first lens element to an image plane of the optical system, and the HFOV is half of a maximum field angle of the optical system.

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

1.5≤(f3+f5)/f≤3；

wherein f3 is an effective focal length of the third lens, f5 is an effective focal length of the fifth lens, and f is an effective focal length of the optical system.

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

-1.5≤R32/f3≤-0.75；

wherein R32 is a radius of curvature of an image side surface of the third lens at an optical axis, and f3 is an effective focal length of the third lens.

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

8≤(R21+R22)/CT2≤15；

wherein R21 is a radius of curvature of an object-side surface of the second lens element at an optical axis, R22 is a radius of curvature of an image-side surface of the second lens element at the optical axis, and CT2 is a thickness of the second lens element at the optical axis.

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

2.6≤CT5/ET5≤3；

wherein CT5 is a thickness of the fifth lens element in an optical axis direction, and ET5 is a distance from a maximum effective aperture of an object-side surface of the fifth lens element to a maximum effective aperture of an image-side surface of the fifth lens element in the optical axis direction.

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

SD11/tan(HFOV)≤1.1mm；

wherein SD11 is half of the maximum effective aperture of the object-side surface of the first lens, and HFOV is half of the maximum field angle of the optical system.

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

-3≤f5/(SAG51+SAG52)≤-1.5；

wherein f5 is the effective focal length of the fifth lens, SAG51 is the saggital height of the object-side surface of the fifth lens at the maximum effective aperture, and SAG52 is the saggital height of the image-side surface of the fifth lens at the maximum effective aperture.

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

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