CN115480365A

CN115480365A - Optical system, image capturing module and electronic equipment

Info

Publication number: CN115480365A
Application number: CN202210907869.9A
Authority: CN
Inventors: 徐标; 李翔宇; 王国贵
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2022-07-29
Filing date: 2022-07-29
Publication date: 2022-12-16
Anticipated expiration: 2042-07-29
Also published as: CN115480365B

Abstract

The invention relates to an optical system, an image capturing module and an electronic device. The optical system comprises a first lens element with positive refractive power having a convex object-side surface at a paraxial region and a concave image-side surface at the paraxial region; a second lens element with refractive power having a convex object-side surface at paraxial region and a concave image-side surface at paraxial region; a third lens element with refractive power having a convex image-side surface at paraxial region; a fourth lens element with refractive power having a convex image-side surface at paraxial region; a fifth lens element with refractive power; a sixth lens element with refractive power; a seventh lens element with positive refractive power having a convex object-side surface and a concave image-side surface; an eighth lens element with negative refractive power having a convex object-side surface and a concave image-side surface; the optical system satisfies: TTL/ImgH is more than or equal to 1.2 and less than or equal to 1.3; TTL/f is more than or equal to 1.2 and less than or equal to 1.3. The optical system has good imaging quality and miniaturization design.

Description

Optical system, image capturing module and electronic equipment

Technical Field

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

Background

With the rapid development of the camera shooting technology, the camera shooting lens is more and more widely applied to electronic devices such as smart phones, tablet computers and electronic readers, and the requirement of the industry on the imaging quality of the camera shooting lens is higher and higher. The imaging quality of the existing camera lens is generally improved by increasing the number of lenses. However, the size of the current camera lens is usually too large while the imaging quality is improved, and it is difficult to achieve both good imaging quality and miniaturization design.

Disclosure of Invention

Accordingly, there is a need to provide an optical system, an image capturing module and an electronic device, which are capable of solving the problem that the conventional optical system cannot achieve both good imaging quality and miniaturization design.

An optical system, wherein the number of lenses with refractive power is eight, the optical system sequentially comprises from an object side to an image side along an optical axis:

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

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

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

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

a fifth lens element with refractive power;

a sixth lens element with refractive power;

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

an eighth 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:

1.2≤TTL/ImgH≤1.3；

1.2≤TTL/f≤1.3；

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, i.e., a total optical length of the optical system, imgH is a half of an image height corresponding to a maximum field angle of the optical system, and f is an effective focal length of the optical system.

In the optical system, the first lens element has positive refractive power, the object-side surface of the first lens element is convex at the paraxial region, and the object-side surface of the second lens element is convex at the paraxial region, so that incident light can be effectively converged, thereby facilitating shortening of the total length of the optical system and achieving miniaturization. The second lens is convex-concave at the position near the optical axis, so that light can smoothly transit in the second lens, the second lens is matched with the refractive power of the first lens and the convex-concave, the on-axis spherical aberration of the optical system can be corrected, and the imaging quality of the optical system can be improved. The image side surfaces of the third lens and the fourth lens are convex surfaces at the position of a paraxial region, and can be matched with the first lens to further converge light, so that the total length of the optical system is further shortened. The fifth lens element and the sixth lens element have refractive power, the seventh lens element has positive refractive power, and the seventh lens element is concave and convex at a paraxial region thereof, thereby facilitating correction of coma aberration of the optical system and improving imaging quality of the optical system. The eighth lens element with negative refractive power can correct curvature of field of the optical system and improve the imaging quality of the optical system. The negative refractive power of the eighth lens element is matched with the concave surface type of the image side surface of the eighth lens element at the optical axis, so that the light can be reasonably transited to the imaging surface, the realization of the large image surface characteristic is facilitated, the incident angle of the light on the imaging surface can be better matched with the photosensitive element to obtain good imaging quality, the reduction of the sensitivity of the optical system is facilitated, and the engineering manufacture of the optical system is facilitated.

When TTL/ImgH is more than or equal to 1.2 and less than or equal to 1.3, the ratio of the total optical length to the half-image height of the optical system can be reasonably configured, the total length of the optical system can be shortened, and the miniaturization design can be realized. When TTL/f is more than or equal to 1.2 and less than or equal to 1.3, the ratio of the total optical length to the effective focal length of the optical system can be reasonably configured, the total length of the optical system can be shortened, the miniaturization design can be realized, and meanwhile, the phenomenon that the field angle of the optical system is too large to be beneficial to the balance of aberration can be prevented, so that the miniaturization design and the good imaging quality can be considered. When the optical length is less than the lower limit of the conditional expression, the total optical length of the optical system is too short, the structure is too compact, the aberration sensitivity of the optical system is increased, and the aberration correction of the optical system is difficult; at the same time, the field angle of the optical system is too small, and it is difficult to realize a large field characteristic. Exceeding the upper limit of above-mentioned conditional expression, optical system's optical total length overlength is unfavorable for the realization of miniaturized design, and optical system's angle of vision is too big simultaneously, leads to the light of marginal visual field to be difficult to image on the effective imaging area of imaging, thereby causes the imaging information incomplete, is unfavorable for the promotion of image quality.

An image capturing module includes a photosensitive element and the optical system of any of the above embodiments, wherein the photosensitive element is disposed at an image side of the optical system. The optical system is adopted in the image capturing module, so that the size of the image capturing module can be reduced, the image capturing module has large image surface characteristics, and good imaging quality and miniaturization design are both considered.

An electronic device comprises a shell and the image capturing module, wherein the image capturing module is arranged on the shell. The image capturing module is adopted in the electronic equipment, so that the size of the electronic equipment is reduced, the electronic equipment has large image surface characteristics, and good imaging quality and miniaturization design are both considered.

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 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 according to 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 structural diagram of an optical system according to a seventh embodiment of the present application;

FIG. 14 is a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system in a seventh embodiment of the present application;

fig. 15 is a schematic view of an image capturing module according to an embodiment of the present application;

fig. 16 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 more comprehensible, embodiments accompanying 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 explicitly stated or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly, e.g., as being permanently connected, detachably connected, or integral; 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.

Referring to fig. 1, in some embodiments of the present application, an optical system 100 includes, in order from an object side to an image side along an optical axis 110, a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, a fifth lens element L5, a sixth lens element L6, a seventh lens element L7, and an eighth lens element L8. 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, the sixth lens element L6 includes an object-side surface S11 and an image-side surface S12, the seventh lens element L7 includes an object-side surface S13 and an image-side surface S14, and the eighth lens element L8 includes an object-side surface S15 and an image-side surface S16. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8 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. In some embodiments, the optical system 100 further includes an image plane S19 located on the image side of the eighth lens L8, and the incident light can be imaged on the image plane S19 after being adjusted by the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8.

The first lens element L1 with positive refractive power has a convex object-side surface S1 at a paraxial region 110 of the first lens element L1, and the second lens element L2 has a convex object-side surface S3 at a paraxial region 110 of the second lens element L, so that incident light beams can be effectively converged, thereby facilitating shortening of the total length of the optical system 100 and achieving miniaturization. The image-side surface S2 of the first lens element L1 is concave at the paraxial region 110. The second lens element L2 with refractive power has a convex-concave shape at a paraxial region 110, which is favorable for light to smoothly transition at the second lens element L2, and is matched with the refractive power of the first lens element L1 to correct the on-axis spherical aberration of the optical system 100, thereby improving the imaging quality of the optical system 1100. The image-side surfaces of the third lens element L3 and the fourth lens element L4 are convex at the paraxial region 110, and can cooperate with the first lens element L1 to further converge light, thereby further shortening the overall length of the optical system 100. The fifth lens element L5 and the sixth lens element L6 have refractive power, the seventh lens element L7 has positive refractive power, and the seventh lens element L7 is concave-convex at a position near the optical axis 110, which is beneficial to correcting coma aberration of the optical system 100 and improving the imaging quality of the optical system 100. The eighth lens element L8 with negative refractive power helps to correct curvature of field of the optical system 100, thereby improving the imaging quality of the optical system 100. The negative refractive power of the eighth lens element L8 cooperates with the concave surface at the optical axis 110 of the image-side surface S16 of the eighth lens element L8 to facilitate reasonable transition of light to the image-forming surface S19, so as to facilitate realization of large image plane characteristics, facilitate better matching of an incident angle of light on the image-forming surface S19 with a photosensitive element to obtain good imaging quality, and facilitate reduction of sensitivity of the optical system 100 and engineering manufacturing of the optical system. The object-side surface S15 of the eighth lens element L8 is convex at the paraxial region 110.

In addition, in some embodiments, the optical system 100 is provided with a stop STO, which may be disposed on the object side of the first lens L1 or between any two lenses, for example, the stop STO is disposed on the object side of the first lens L1. In some embodiments, the optical system 100 further includes an infrared cut filter L9 disposed on the image side of the eighth lens L7. The infrared cut filter L8 can be used to filter out the interference light, and prevent the interference light from reaching the imaging surface S19 of the optical system 100 to affect the normal imaging.

In some embodiments, the object-side surface and the image-side surface of each lens of optical system 100 are 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 should be noted that the first lens L1 does not mean that there is only one lens, and in some embodiments, there may be two or more lenses in the first lens L1, 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, no cemented lens is formed between the lenses of the first lens L1, but the distance between the lenses is relatively fixed, in which case, the object-side surface of the lens closest to the object side is the object-side surface S1, and the image-side surface of the lens closest to the image side is the image-side surface S2. In addition, the number of lenses in the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, or the eighth lens L8 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 a non-cemented lens may also be used.

Further, in some embodiments, the optical system 100 satisfies the conditional expression: f tan (HFOV) is less than or equal to 8.5mm and is more than or equal to 7.8 mm; where f is the effective focal length of the optical system 100 and the HFOV is half the maximum field angle of the optical system 100. Specifically, f tan (HFOV) may be: 7.8, 7.935, 7.964, 7.998, 8.025, 8.124, 8.175, 8.233, 8.365 or 8.5, the numerical units being mm. When the above conditional expressions are satisfied, the total length of the optical system 100 is shortened by matching with the refractive power and the surface shape configuration of each lens of the optical system 100, and the miniaturization design is realized, and at the same time, the optical system 100 can have a large image plane characteristic, so that the optical system 100 can be matched with a large-sized photosensitive element to obtain high resolution, and further the optical system 100 has the characteristics of high pixel and high definition, and can give consideration to both good imaging quality and miniaturization design.

In some embodiments, the optical system 100 satisfies the conditional expression: R6/R8 is more than 0 and less than or equal to 2.3; wherein R6 is a curvature radius of the image-side surface S6 of the third lens element L3 at the optical axis 110, and R8 is a curvature radius of the image-side surface S8 of the fourth lens element L4 at the optical axis 110. Specifically, R6/R8 may be: 0.028, 0.337, 0.569, 0.847, 1.022, 1.542, 1.896, 2.002, 2.114 or 2.3. When the above conditional expressions are satisfied, the ratio of the curvature radii of the image side surfaces of the third lens L3 and the fourth lens L4 can be reasonably configured, which is beneficial to balancing the aberration of the optical system 100 and reducing the aberration sensitivity of the optical system 100, thereby improving the imaging quality of the optical system 100, and simultaneously being beneficial to reducing the tolerance sensitivity of the optical system 100, thereby being beneficial to the engineering manufacture of the optical system 100. If the lower limit of the conditional expression is lower, the image side surface S6 of the third lens L3 is excessively curved, which increases the tolerance sensitivity of the optical system 100, and is disadvantageous to the engineering of the optical system 100. If the upper limit of the above conditional expression is exceeded, the image side surface S6 of the third lens L3 is too gentle, and it becomes difficult to effectively correct aberrations such as curvature of field of the optical system 100, which results in poor imaging performance of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: r6/f is more than or equal to-5 and less than or equal to-0.5; where R6 is a curvature radius of the image-side surface S6 of the third lens element L3 at the optical axis 110. Specifically, | R6/f | may be: -0.5, -0.692, -0.723, -0.755, -0.789, -0.854, -0.937, -1.556, -2.678 or-5. When the above conditional expressions are satisfied, the ratio of the curvature radius of the image-side surface S6 of the third lens element L3 to the effective focal length of the optical system 100 can be reasonably configured, which is favorable for reasonably distributing the refractive power ratio of the third lens element L3 in the optical system 100, so as to effectively balance the spherical aberration of the optical system 100, and make the optical system 100 have good imaging quality. Exceeding the upper limit of the conditional expression, the image side surface S6 of the third lens L3 is excessively curved, which is disadvantageous to design and molding of the third lens L3. Below the lower limit of the above conditional expression, the image-side surface S6 of the third lens L3 is too gentle to correct aberrations such as spherical aberration of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: r8/f is more than or equal to-30 and less than or equal to-1.5; where R8 is a curvature radius of the image-side surface S8 of the fourth lens element L4 at the optical axis 110. Specifically, | R8/f | may be: -1.5, -2.312, -3.565, -4.951, -5.365, -6.742, -7.652, -8.722, -10.635 or-30. When the above conditional expressions are satisfied, the ratio of the curvature radius of the image-side surface S8 of the fourth lens element L4 to the effective focal length of the optical system 100 can be reasonably configured, which is favorable for reasonably distributing the refractive power of the fourth lens element L4 in the optical system 100, so as to effectively balance the aberrations such as astigmatism and distortion of the optical system 100, and thus the optical system 100 has good imaging quality. Exceeding the upper limit of the conditional expression, the image-side surface S8 of the fourth lens L4 is excessively curved, which is disadvantageous to the design and molding of the fourth lens L4. Below the lower limit of the conditional expression, the surface profile of the image side surface S8 of the fourth lens L4 is too gentle, and it is difficult to effectively balance aberrations such as astigmatism and distortion of the optical system 100, which is disadvantageous to improvement of image quality.

In some embodiments, the optical system 100 satisfies the conditional expression: r15/f is more than or equal to 1 and less than or equal to 3; where R15 is a curvature radius of the object-side surface S15 of the eighth lens element L8 at the optical axis 110. Specifically, R15/f may be: 1. 1.358, 1.674, 1.932, 2.112, 2.347, 2.521, 2.639, 2.807, or 3. When the above conditional expressions are satisfied, the ratio of the curvature radius of the object-side surface S15 of the eighth lens element L8 to the effective focal length of the optical system 100 can be reasonably configured, which is favorable for reasonably distributing the refractive power ratio of the eighth lens element L8 in the optical system 100, so that the eighth lens element L8 can effectively diverge the light to the imaging surface S19, which is favorable for reducing the incident angle of the marginal field-of-view light incident to the imaging surface S19, thereby improving the matching degree of the optical system 100 and the photosensitive chip, and simultaneously being favorable for improving the astigmatism of the off-axis field of view, and improving the imaging quality of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: CT3/CT4 is more than or equal to 1 and less than or equal to 2.2; wherein, CT3 is the thickness of the third lens element L3 on the optical axis 110, and CT4 is the thickness of the fourth lens element L4 on the optical axis 110. Specifically, CT3/CT4 may be: 1. 1.234, 1.365, 1.474, 1.528, 1.694, 1.752, 1.863, 1.965, or 2.2. When satisfying above-mentioned conditional expression, can the ratio of rational arrangement third lens L3 and fourth lens L4's central thickness, make third lens L3 and fourth lens L4 can effectively rectify optical system 100's field curvature, promote optical system 100's imaging quality, still be favorable to shortening optical system 100's overall length simultaneously, thereby be favorable to the realization of miniaturized design, in addition still be favorable to making third lens L3 and fourth lens L4's shape can not too extreme, thereby be favorable to third lens L3 and fourth lens L4's machine-shaping, be favorable to optical system 100's engineering manufacturing.

In some embodiments, the optical system 100 satisfies the conditional expression: 1.4 is more than or equal to AT23/max (AT 12, AT34, AT 45) is more than or equal to 5; the AT23 is a distance between the image-side surface S4 of the second lens element L2 and the object-side surface S5 of the third lens element L3 on the optical axis 110, the AT12 is a distance between the image-side surface S2 of the first lens element L1 and the object-side surface S3 of the second lens element L2 on the optical axis 110, the AT34 is a distance between the image-side surface S6 of the third lens element L3 and the object-side surface S7 of the fourth lens element L4 on the optical axis 110, the AT45 is a distance between the image-side surface S8 of the fourth lens element L4 and the object-side surface S9 of the fifth lens element L5 on the optical axis 110, and max (AT 12, AT34, AT 45) is a maximum value among the AT12, AT34, and AT 45. Specifically, AT23/max (AT 12, AT34, AT 45) may be: 1.4, 1.867, 2.026, 2.334, 2.745, 2.965, 3.356, 3.667, 3.856 or 5. When the above conditional expressions are satisfied, the air space between the lenses of the optical system 100 can be reasonably configured, so that the structure of the optical system 100 is not too compact, the sensitivity of the assembly of the optical system 100 is favorably reduced, the assembly yield is improved, meanwhile, the variation of the field curvature is favorably compensated through the reasonable air space, and the imaging quality of the optical system 100 is favorably improved.

In some embodiments, the optical system 100 satisfies the conditional expression: AT56/TD is more than or equal to 0.08 and less than or equal to 0.12; here, AT56 is a distance between the image-side surface S10 of the fifth lens element L5 and the object-side surface S11 of the sixth lens element L6 on the optical axis 110, and TD is a distance between the object-side surface S1 of the first lens element L1 and the image-side surface S16 of the eighth lens element L8 on the optical axis 110. Specifically, the AT56/TD may be: 0.08, 0.097, 0.098, 0.102, 0.105, 0.106, 0.108, 0.110, 0.111, or 0.12. When the above conditional expressions are satisfied, the ratio of the air interval between the fifth lens L5 and the sixth lens L6 to the distance between the object-side surface S1 of the first lens L1 and the image-side surface S16 of the eighth lens L8 can be configured reasonably, which is beneficial to balancing the contribution of the fifth lens L5 and the sixth lens L6 to the curvature of field of the optical system 100, thereby improving the imaging quality of the optical system 100, and simultaneously, is beneficial to shortening the total length of the optical system 100 and realizing the miniaturization design of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: AT78/TD is more than or equal to 0.16 and less than or equal to 0.19; wherein, AT78 is a distance between the image-side surface S14 of the seventh lens element L7 and the object-side surface S15 of the eighth lens element L8 on the optical axis 110, and TD is a distance between the object-side surface S1 of the first lens element L1 and the image-side surface S16 of the eighth lens element L8 on the optical axis 110. Specifically, AT78/TD may be: 0.16, 0.172, 0.175, 0.176, 0.177, 0.179, 0.180, 0.183, 0.184 or 0.19. When the above conditional expressions are satisfied, the ratio of the air space between the seventh lens L7 and the eighth lens L8 to the distance from the object-side surface S1 of the first lens L1 to the image-side surface S16 of the eighth lens L8 can be reasonably configured, which is beneficial to balancing the proportion of the air space between the seventh lens L7 and the eighth lens L8 in the axial dimension of the optical system 100, so that the light can be smoothly transited between the seventh lens L7 and the eighth lens L8, and then effectively diverged to the imaging surface S19 through the eighth lens L8, thereby being beneficial to improving the incident angle of the chief ray of the optical system 100 on the imaging surface S19 and the matching of the photosensitive element, and further being beneficial to improving the imaging quality of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: SD11/SD52 is more than or equal to 0.8 and less than or equal to 0.88; where SD11 is the maximum effective half-aperture of the object-side surface S1 of the first lens L1, and SD52 is the maximum effective half-aperture of the image-side surface S10 of the fifth lens L5. Specifically, SD11/SD52 may be: 0.8, 0.825, 0.829, 0.835, 0.842, 0.847, 0.853, 0.855, 0.859 or 0.88. When the condition formula is satisfied, the ratio of the maximum effective half aperture of the object-side surface S1 of the first lens L1 to the maximum effective half aperture of the image-side surface S10 of the fifth lens L5 can be reasonably configured, so that the first lens L1 can collect light rays with a large angle, and the optical system 100 is favorable for having a large aperture characteristic, so that the optical system 100 has a sufficient light entering amount, and further the imaging quality of the optical system 100 in low-light environments such as night and rainy days is favorable for improving the field angle of the optical system 100, and the requirement of large-range image capture is satisfied; meanwhile, the fifth lens L5 can effectively collect and converge light, thereby being beneficial to shortening the total length of the optical system 100 and realizing the miniaturized design; in addition, the aperture of the optical system 100 is not too large, the radial dimension of the optical system 100 is configured reasonably, and the miniaturization design of the optical system 100 is also facilitated. Exceeding the upper limit of the above conditional expression, the maximum effective aperture of the object-side surface S1 of the first lens L1 becomes too large, which is disadvantageous for the compact design of the optical system 100. Being less than the lower limit of above-mentioned conditional expression, the effective bore undersize of the object side S1 of first lens L1 is unfavorable for first lens L1 to collect wide-angle light to be unfavorable for the realization of large aperture and big angle of vision, fifth lens L5' S effective bore is too big simultaneously, is unfavorable for drawing in light, thereby is unfavorable for the realization of miniaturized design.

In some embodiments, the optical system 100 satisfies the conditional expression: 0.6-0.85 of (SD 62-SD 71)/(SD 72-SD 81); here, SD62 is the maximum effective half-aperture of the image-side surface S12 of the sixth lens L6, SD71 is the maximum effective half-aperture of the object-side surface S13 of the seventh lens L7, SD72 is the maximum effective half-aperture of the image-side surface S14 of the seventh lens L7, and SD81 is the maximum effective half-aperture of the object-side surface S15 of the eighth lens L8. Specifically, (SD 62-SD 71)/(SD 72-SD 81) may be: 0.6, 0.634, 0.655, 0.702, 0.741, 0.763, 0.792, 0.822, 0.835 or 0.85. When the above conditional expressions are satisfied, the relationship among the effective apertures of the image-side surface S12 of the sixth lens L6, the object-side surface S13 and the image-side surface S14 of the seventh lens L7, and the object-side surface S15 of the eighth lens L8 can be reasonably configured, which is beneficial to reducing the step difference of the effective apertures between the sixth lens L6, the seventh lens L7, and the eighth lens L8, and is beneficial to enabling light to smoothly transition between the sixth lens L6, the seventh lens L7, and the eighth lens L8, and reducing the deflection degree of the light, thereby being beneficial to balancing the aberration of the marginal field of view of the optical system 100, and simultaneously reducing the aberration sensitivity of the marginal field of view, and further improving the imaging quality of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: MAX56/MIN56 is more than or equal to 1.1 and less than or equal to 1.6; wherein, MAX56 is a maximum distance between the image-side surface S10 of the fifth lens element L5 and the object-side surface S11 of the sixth lens element L6 along the optical axis 110, and MIN56 is a minimum distance between the image-side surface S10 of the fifth lens element L5 and the object-side surface S11 of the sixth lens element L6 along the optical axis 110. Specifically, MAX56/MIN56 may be: 1.1, 1.202, 1.244, 1.267, 1.365, 1.398, 1.425, 1.477, 1.502, or 1.6. When the above conditional expressions are satisfied, the ratio of the maximum distance and the minimum distance in the direction of the optical axis 110 between the image-side surface S10 of the fifth lens element L5 and the object-side surface S11 of the sixth lens element L6 can be configured reasonably, so that the surface shapes of the fifth lens element L5 and the sixth lens element L6 are not too curved, which is beneficial to reducing the local astigmatism of the optical system 100, and reducing the tolerance sensitivity of the optical system 100, which is beneficial to the engineering manufacture of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: TTL/ImgH is more than or equal to 1.2 and less than or equal to 1.3; wherein, TTL is a distance from the object-side surface S1 of the first lens element L1 to the image plane S19 of the optical system 100 on the optical axis 110, i.e. the total optical length of the optical system 100, and ImgH is half of the image height corresponding to the maximum field angle of the optical system 100. Specifically, TTL/ImgH can be: 1.2, 1.224, 1.235, 1.246, 1.257, 1.269, 1.270, 1.281, 1.292, or 1.3. When the above conditional expressions are satisfied, the ratio of the total optical length to the half-image height of the optical system 100 can be configured reasonably, which is beneficial to shortening the total optical length of the optical system 100 and realizing miniaturization design.

In some embodiments, the optical system 100 satisfies the conditional expression: the absolute value of R12+ R13/| R12-R13| is more than or equal to 0.8 and less than or equal to 1.2. Specifically, | R12+ R13|/| R12-R13| may be: 0.8, 0.936, 1.025, 1.055, 1.089, 1.103, 1.128, 1.147, 1.155, or 1.2. When the above conditional expressions are satisfied, the curvature radii of the image side surface S12 of the sixth lens L6 and the object side surface S13 of the seventh lens L7 can be reasonably configured, so that the tendency of light between the sixth lens L6 and the seventh lens L7 can be reasonably configured, the light can be smoothly transited between the sixth lens L6 and the seventh lens L7, thereby balancing the high-level coma aberration of the optical system 100, and improving the imaging quality of the optical system 100; meanwhile, the surface shapes of the sixth lens L6 and the seventh lens L7 are not excessively bent, so that the tolerance sensitivities of the sixth lens L6 and the seventh lens L7 are reduced, and the molding and the assembly of the optical system 100 are facilitated.

In some embodiments, the optical system 100 satisfies the conditional expression: r4/f2 is more than 0 and less than or equal to 0.4; where R4 is a curvature radius of the image-side surface S4 of the second lens element L2 at the optical axis 110, and f2 is an effective focal length of the second lens element L2. Specifically, | R4/f2| may be: 0.009, 0.102, 0.155, 0.189, 0.234, 0.255, 0.267, 0.298, 0.305 or 0.4. When the above conditional expressions are satisfied, a ratio of the curvature radius of the image-side surface S4 of the second lens element L2 to the effective focal length of the second lens element L2 can be reasonably configured, which is beneficial to suppressing astigmatism of the second lens element L2, and enables the second lens element L2 to effectively balance astigmatism generated by the first lens element L1, thereby being beneficial to improving the imaging quality of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: f1/f is more than or equal to 0.9 and less than or equal to 1.3; where f1 is the effective focal length of the first lens L1, and f is the effective focal length of the optical system 100. Specifically, it may be: 0.9, 0.937, 0.974, 0.996, 1.152, 1.174, 1.205, 1.235, 1.268, or 1.3. When the above conditional expressions are satisfied, the ratio of the effective focal lengths of the first lens element L1 and the optical system 100 can be configured, so as to reasonably configure the refractive power contribution of the first lens element L1 in the optical system 100, which is beneficial to correcting the high-order spherical aberration of the optical system 100 and improving the imaging quality of the optical system 100; and at the same time, it is advantageous to shorten the overall length of the optical system 100 and to realize a compact design. Exceeding the upper limit of the above conditional expressions, the positive refractive power of the first lens element L1 is too weak to efficiently converge light, which is not favorable for the realization of the miniaturized design. Below the lower limit of the above conditional expression, the positive refractive power of the first lens element L1 is too strong to correct the high-order spherical aberration of the optical system 100, thereby being unfavorable to improve the imaging quality.

In some embodiments, the optical system 100 satisfies the conditional expression: the absolute value of SAG61/CT6 is more than or equal to 0.5 and less than or equal to 1.2; here, SAG61 is a distance from an intersection point of the object-side surface S11 of the sixth lens L6 and the optical axis 110 to a maximum effective aperture of the object-side surface S11 of the sixth lens L6 in the direction of the optical axis 110, that is, a sagittal height of the object-side surface S11 of the sixth lens L6 at the maximum effective aperture, and CT6 is a thickness of the sixth lens L6 on the optical axis 110, that is, a central thickness of the sixth lens L6. Specifically, | SAG61/CT6| may be: 0.5, 0.654, 0.682, 0.763, 0.781, 0.822, 0.854, 0.963, 1.023, or 1.2. When the conditional expressions are met, the ratio of the rise of the object side surface S11 of the sixth lens L6 to the center thickness can be reasonably configured, so that the shape of the sixth lens L6 is optimized, the surface shape of the sixth lens L6 cannot be excessively bent, the tolerance sensitivity of the sixth lens L6 is favorably reduced, the processing and forming of the sixth lens L6 are favorably realized, and the engineering manufacturing is better realized.

In some embodiments, the optical system 100 satisfies the conditional expression: AT67/CT7 is more than or equal to 0.12 and less than or equal to 0.32; here, AT67 is a distance between the image-side surface S12 of the sixth lens element L6 and the object-side surface S13 of the seventh lens element L7 on the optical axis 110, and CT7 is a thickness of the seventh lens element L7 on the optical axis 110, i.e., a central thickness of the seventh lens element L7. Specifically, the AT67/CT7 may be: 0.12, 0.155, 0.172, 0.193, 0.221, 0.265, 0.299, 0.302, 0.305, or 0.32. When the above conditional expressions are satisfied, the ratio of the air interval of the sixth lens L6 and the seventh lens L7 on the optical axis 110 and the central thickness of the seventh lens L7 can be reasonably configured, so that the sixth lens L6 and the seventh lens L7 can effectively balance the high-order aberration generated by the optical system 100, and simultaneously, the field curvature adjustment of the optical system 100 in the engineering manufacturing is facilitated, thereby facilitating the improvement of the imaging quality of the optical system 100; in addition, the light is favorably and reasonably deflected to the imaging surface S19 through the sixth lens L6 and the seventh lens L7, the matching degree of the incident angle of the chief ray on the imaging surface S19 and the photosensitive element is improved, and the imaging quality of the optical system 100 is further improved. If the air gap between the sixth lens L6 and the seventh lens L7 is too small, the light beam is too much deflected between the sixth lens L6 and the seventh lens L7, which makes it difficult to effectively balance the high-order aberrations of the optical system 100, and is not favorable for improving the image quality. Exceeding the upper limit of the above conditional expression, the incident angle of the chief ray of the imaging surface S19 is difficult to match with the photosensitive element, and is also not favorable for improving the imaging quality.

In some embodiments, the optical system 100 satisfies the conditional expression: R4/R5 is more than 0 and less than or equal to 0.4; wherein, R4 is a curvature radius of the image-side surface S4 of the second lens element L2 at the optical axis 110, and R5 is a curvature radius of the object-side surface S5 of the third lens element L3 at the optical axis 110. Specifically, | R4/R5| may be: 0.015, 0.067, 0.123, 0.157, 0.236, 0.277, 0.311, 0.352, 0.376 or 0.4. When the above conditional expressions are satisfied, the ratio of the curvature radii of the image-side surface S4 of the second lens L2 and the object-side surface S5 of the third lens L3 on the optical axis 110 can be reasonably configured, so that the second lens L2 and the third lens L3 can effectively balance aberrations such as field curvature of the optical system 100, and the aberration sensitivity of the optical system 100 is reduced, thereby being beneficial to improving the imaging quality of the optical system 100; meanwhile, the surface shapes of the second lens L2 and the third lens L3 are not excessively bent, so that the tolerance sensitivity of the optical system 100 is reduced, and the engineering manufacture of the optical system 100 is facilitated. Below the lower limit of the conditional expression, the surface shape of the image-side surface S4 of the second lens L2 is too curved, which increases the tolerance sensitivity of the optical system 100 and is not favorable for the engineering of the optical system 100. Exceeding the upper limit of the above conditional expressions, it is difficult for the second lens L2 and the third lens L3 to effectively correct aberrations such as curvature of field of the optical system 100, which is disadvantageous for improvement of image quality.

In some embodiments, the optical system 100 satisfies the conditional expression: TTL/f is more than or equal to 1.2 and less than or equal to 1.3; wherein, TTL is a distance from the object-side surface S1 of the first lens element L1 to the image plane S19 of the optical system 100 on the optical axis 110, i.e. the total optical length of the optical system 100, and f is an effective focal length of the optical system 100. Specifically, TTL/f can be: 1.2, 1.242, 1.247, 1.253, 1.257, 1.260, 1.265, 1.267, 1.269 or 1.3. When the above conditional expressions are satisfied, the ratio of the total optical length of the optical system 100 to the effective focal length can be configured reasonably, which is advantageous for shortening the total optical length of the optical system 100, realizing a miniaturized design, and preventing an excessively large field angle of the optical system 100 from being detrimental to the balance of aberrations, thereby enabling both the miniaturized design and good imaging quality. When the lower limit of the above conditional expression is lower, the total optical length of the optical system is too short, and the structure is too compact, so that the aberration sensitivity of the optical system 100 is increased, and the aberration correction of the optical system 100 is difficult; at the same time, the angle of view of the optical system 100 is too small, and it is difficult to realize a large field of view characteristic. Exceeding the upper limit of the above conditional expression, the total optical length of the optical system is too long, which is not favorable for realizing the miniaturization design, and meanwhile, the field angle of the optical system 100 is too large, which causes the light of the marginal field of view to be difficult to image on the effective imaging area of the imaging surface S19, thereby causing incomplete imaging information and being unfavorable for improving the imaging quality.

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 S19 of the optical system 100 coincides with the photosensitive surface of the photosensitive element. At this time, the effective pixel area on the imaging plane S19 of the optical system 100 has a horizontal direction and a diagonal direction, and the maximum field angle FOV can be understood as the maximum field angle of the optical system 100 in the diagonal direction, and ImgH can be understood as a half of the length of the effective pixel area on the imaging plane S19 of the optical system 100 in the diagonal direction.

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

Based on the above description of the embodiments, more specific embodiments and drawings are set forth below for detailed description. Although the embodiment of the present application has been described by taking eight lenses as an example, the number of lenses having refractive power in the optical system 100 is not limited to eight, and the optical system 100 may include other numbers of lenses. It will be understood by those skilled in the art that the number of lenses constituting the optical system may be varied to achieve the various results and advantages described in the present specification without departing from the technical solutions claimed in the present application.

First embodiment

Referring to fig. 1 and fig. 2, fig. 1 is a schematic structural diagram of an optical system 100 in the first embodiment, and the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, a sixth lens element L6 with negative refractive power, a seventh lens element L7 with positive refractive power, and an eighth lens element L8 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, in which the reference wavelength of the astigmatism diagram and the distortion diagram is 555nm, from left to right, and other embodiments are the same.

The object-side surface S1 of the first lens element L1 is convex at the paraxial region 110, and the image-side surface S2 is concave at the paraxial region 110;

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;

the object-side surface S5 of the third lens element L3 is convex at the paraxial region 110, and the image-side surface S6 is convex at the paraxial region 110;

the object-side surface S7 of the fourth lens element L4 is concave at the paraxial region 110, and the image-side surface S8 is convex at the paraxial region 110;

the object-side surface S9 of the fifth lens element L5 is concave at the paraxial region 110, and the image-side surface S10 is convex at the paraxial region 110;

the object-side surface S11 of the sixth lens element L6 is concave at the paraxial region 110, and the image-side surface S12 is concave at the paraxial region 110;

the object-side surface S13 of the seventh lens element L7 is convex at the paraxial region 110, and the image-side surface S14 is concave at the paraxial region 110;

the object-side surface S15 of the eighth lens element L8 is convex at the paraxial region 110, and the image-side surface S16 is concave at the paraxial region 110.

The object-side surface and the image-side surface of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are aspheric.

The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are all made of plastic.

In addition, the parameters of the optical system 100 are given in table 1. In which elements from an object plane (not shown) to an image plane S19 are sequentially arranged in the order of 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. The surface number S1 and the surface number S2 are 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 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 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.

It should be noted that in this embodiment and the following embodiments, the optical system 100 may not be provided with the ir-cut filter L9, but the distance from the image side surface S16 of the eighth lens L8 to the image plane S19 is kept unchanged.

In the first embodiment, the effective focal length f =8.71mm, the total optical length TTL =10.8mm, the maximum field angle FOV =86.51deg, and the f-number FNO =1.75 of the optical system 100.

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

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 S16 represent image side surfaces or object side surfaces S1 to S16, respectively. And K-a20 from top to bottom respectively represent the types of aspheric coefficients, where K represents a conic coefficient, A4 represents a quartic aspheric coefficient, A6 represents a sextic aspheric coefficient, A8 represents an octa aspheric coefficient, and so on. In addition, the aspherical surface coefficient formula is as follows:

wherein 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 type formula.

TABLE 2

In addition, fig. 2 includes a Longitudinal Spherical Aberration diagram (Longitudinal Spherical Aberration) of the optical system 100, where the Longitudinal Spherical Aberration curve represents the convergent focus deviation of light rays with different wavelengths after passing through the lens, where the ordinate represents Normalized Pupil coordinates (Normalized Pupil Coordinator) from the Pupil center to the Pupil edge, and the abscissa represents focus deviation, i.e., the distance (in mm) from the image plane S17 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 the wavelengths in the first embodiment tend to be consistent, and the diffuse spots or the 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 in the astigmatism graph represents the sagittal FIELD curvature at 555nm and the T-curve represents the meridional FIELD curvature at 555nm. 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, the DISTORTION plot representing DISTORTION magnitude values corresponding to different angles of view, wherein the abscissa represents the DISTORTION value in mm, and the ordinate represents the 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 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, a sixth lens element L6 with negative refractive power, a seventh lens element L7 with positive refractive power, and an eighth lens element L8 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 object-side surface S5 of the third lens element L3 is concave at the paraxial region 110, and the image-side surface S6 is convex at the paraxial region 110;

the object-side surface S9 of the fifth lens element L5 is convex at the paraxial region 110, and the image-side surface S10 is concave at the paraxial region 110;

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

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, and the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with negative refractive power, a sixth lens element L6 with negative refractive power, a seventh lens element L7 with positive refractive power, and an eighth lens element L8 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.

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 derived from the first embodiment, which is not repeated herein.

TABLE 6

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, and the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, a sixth lens element L6 with negative refractive power, a seventh lens element L7 with positive refractive power, and an eighth lens element L8 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.

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 derived from the first embodiment, which is not repeated herein.

TABLE 8

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 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, a sixth lens element L6 with positive refractive power, a seventh lens element L7 with positive refractive power, and an eighth lens element L8 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.

the object-side surface S11 of the sixth lens element L6 is concave at the paraxial region 110, and the image-side surface S12 is convex at the paraxial region 110;

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

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 derived from the first embodiment, which is not repeated herein.

Watch 10

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, and the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with positive refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with negative refractive power, a sixth lens element L6 with negative refractive power, a seventh lens element L7 with positive refractive power, and an eighth lens element L8 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 shown in table 11, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein again.

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 derived from the first embodiment, which is not repeated herein.

TABLE 12

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.

Seventh embodiment

Referring to fig. 13 and 14, fig. 13 is a schematic structural diagram of the optical system 100 in the seventh embodiment, in which the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with negative refractive power, a sixth lens element L6 with negative refractive power, a seventh lens element L7 with positive refractive power, and an eighth lens element L8 with negative refractive power. Fig. 14 is a graph showing the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the seventh embodiment from left to right.

the object-side surface S7 of the fourth lens element L4 is convex at the paraxial region 110, and the image-side surface S8 is convex at the paraxial region 110;

the object-side surface S9 of the fifth lens element L5 is concave at the paraxial region 110, and the image-side surface S10 is concave at the paraxial region 110;

the object-side surface S11 of the sixth lens element L6 is convex at the paraxial region 110, and the image-side surface S12 is concave at the paraxial region 110;

In addition, the parameters of the optical system 100 are shown in table 13, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein again.

Watch 13

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 14, and the definitions of the parameters can be derived from the first embodiment, which is not repeated herein.

TABLE 14

In addition, as can be seen from the aberration diagram in fig. 14, 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.

The above examples also satisfy the data of table 15 below, and the effects obtainable by satisfying the following data can be inferred from the above description.

Watch 15

Referring to fig. 15, in some embodiments, the optical system 100 may be assembled with the photosensitive element 210 to form an image capturing module 200. At this time, the light-sensing surface of the light-sensing element 210 coincides with the image-forming surface S19 of the optical system 100. Specifically, the photosensitive element 210 may be a Charge Coupled Device (CCD) or a Complementary Metal-Oxide Semiconductor (CMOS) Device. By adopting the optical system 100 in the image capturing module 200, the size of the image capturing module 200 can be reduced and the image capturing module 200 has a large image plane characteristic, thereby achieving both good imaging quality and miniaturization design.

Referring to fig. 15 and fig. 16, in some embodiments, the image capturing module 200 may be applied to an electronic device 300, the electronic device 300 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. The image capturing module 200 is adopted in the electronic device 300, which is beneficial to reducing the size of the electronic device 300 and enabling the electronic device 300 to have a large image plane characteristic, thereby considering both good imaging quality and miniaturization design.

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, wherein eight lenses having refractive power are provided, the optical system sequentially including, from an object side to an image side along an optical axis:

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

a fifth lens element with refractive power;

a sixth lens element with refractive power;

and the optical system satisfies the following conditional expression:

1.2≤TTL/ImgH≤1.3；

1.2≤TTL/f≤1.3；

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

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

7.8mm≤f*tan(HFOV)≤8.5mm；

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

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

R6/R8 is more than 0 and less than or equal to 2.3; and/or the presence of a gas in the gas,

r6/f is more than or equal to-5 and less than or equal to-0.5; and/or the presence of a gas in the atmosphere,

-30≤R8/f≤-1.5；

wherein R6 is a curvature radius of the image-side surface of the third lens element on the optical axis, and R8 is a curvature radius of the image-side surface of the fourth lens element on the optical axis.

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

1≤R15/f≤3；

wherein R15 is a curvature radius of an object-side surface of the eighth lens element at an optical axis.

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

1≤CT3/CT4≤2.2；

wherein CT3 is the thickness of the third lens element on the optical axis, and CT4 is the thickness of the fourth lens element on the optical axis.

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

AT23/max (AT 12, AT34, AT 45) is more than or equal to 1.4 and less than or equal to 5; and/or the presence of a gas in the gas,

AT56/TD is more than or equal to 0.08 and less than or equal to 0.12; and/or the presence of a gas in the gas,

0.16≤AT78/TD≤0.19；

wherein AT23 is a distance on an optical axis from an image-side surface of the second lens element to an object-side surface of the third lens element, AT12 is a distance on the optical axis from the image-side surface of the first lens element to an object-side surface of the second lens element, AT34 is a distance on the optical axis from the image-side surface of the third lens element to an object-side surface of the fourth lens element, AT45 is a distance on the optical axis from the image-side surface of the fourth lens element to an object-side surface of the fifth lens element, max (AT 12, AT34, AT 45) is a maximum value among AT12, AT34, AT45, AT56 is a distance on the optical axis from the image-side surface of the fifth lens element to an object-side surface of the sixth lens element, AT78 is a distance on the optical axis from the image-side surface of the seventh lens element to an object-side surface of the eighth lens element, and TD is a distance on the optical axis from the object-side surface of the first lens element to the image-side surface of the eighth lens element.

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

SD11/SD52 is more than or equal to 0.8 and less than or equal to 0.88; and/or the presence of a gas in the atmosphere,

0.6≤(SD62-SD71)/(SD72-SD81)≤0.85；

wherein SD11 is the maximum effective half aperture of the object-side surface of the first lens element, SD52 is the maximum effective half aperture of the image-side surface of the fifth lens element, SD62 is the maximum effective half aperture of the image-side surface of the sixth lens element, SD71 is the maximum effective half aperture of the object-side surface of the seventh lens element, SD72 is the maximum effective half aperture of the image-side surface of the seventh lens element, and SD81 is the maximum effective half aperture of the object-side surface of the eighth lens element.

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

1.1≤MAX56/MIN56≤1.6；

wherein, MAX56 is the image side face of the fifth lens element to the maximum distance of the object side face of the sixth lens element in the optical axis direction, and MIN56 is the image side face of the fifth lens element to the minimum distance of the object side face of the sixth lens element in the optical axis direction.

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.