CN112394475A

CN112394475A - Optical system, image capturing module and electronic device

Info

Publication number: CN112394475A
Application number: CN201910753138.1A
Authority: CN
Inventors: 张文燕; 刘彬彬; 邹海荣
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2019-08-15
Filing date: 2019-08-15
Publication date: 2021-02-23

Abstract

The invention relates to an optical system, an image capturing module and an electronic device, wherein the optical system sequentially comprises a first lens with positive refractive power from an object side to an image side, and the object side surface of the first lens is a convex surface at the circumference; the second lens element with refractive power, the third lens element with refractive power, the fourth lens element with refractive power, the fifth lens element with refractive power, the sixth lens element with refractive power, the seventh lens element with refractive power, and the eighth lens element with negative refractive power have a concave image-side surface at an optical axis. In addition, the optical system satisfies 1 < TTL/L < 2.5; 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, the optical system further includes a stop, and L is an effective aperture diameter of the stop. The optical system satisfying the above relationship has characteristics of a large aperture and a large aperture, and has an ability to obtain a high-quality image in a dark light environment.

Description

Optical system, image capturing module and electronic device

Technical Field

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

Background

Along with social development, electronic products such as mobile phones, tablet computers, unmanned planes and computers are applied more and more widely in life. For electronic products with a camera function, most of the electronic products have low quality of images of scenes shot in a dark environment, and cannot meet the high-quality shooting requirements of the public in environments with insufficient light, such as cloudy days, at night, and the like, so that the improvement of a camera module on the electronic products gradually becomes one of the key points of public attention.

Disclosure of Invention

Accordingly, it is desirable to provide an optical system, an image capturing module and an electronic device for improving the quality of a captured image in a dark environment.

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

a first lens element with positive refractive power having a convex object-side surface at a circumference;

a second lens element with refractive power;

a third lens element with refractive power;

a fourth lens element with refractive power;

a fifth lens element with refractive power;

a sixth lens element with refractive power;

a seventh lens element with refractive power having a concave image-side surface at an optical axis;

an eighth lens element with negative refractive power;

the optical system satisfies the following relationship:

1＜TTL/L＜2.5；

wherein, TTL is a distance on an optical axis from an object-side surface of the first lens element to an imaging surface of the optical system, the optical system further includes a diaphragm, and L is an effective aperture diameter of the diaphragm.

When the above relationship is satisfied, the optical system has the characteristics of a large aperture and a large aperture in performance, has the capability of obtaining a high-quality image in dark light environments such as night scenes, starry sky and cloudy days, has high definition of image quality, and has the characteristic of miniaturization in structure.

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

f14＞0；

f58＜0；

wherein f14 is a combined focal length of the first, second, third, and fourth lenses, and f58 is a combined focal length of the fifth, sixth, seventh, and eighth lenses. When the above relationship is satisfied, the first lens element, the second lens element, the third lens element and the fourth lens element form a first lens group with positive refractive power, and the fifth lens element, the sixth lens element, the seventh lens element and the eighth lens element form a second lens group with negative refractive power. The positive and negative refractive powers of the first lens group and the second lens group are matched with each other to achieve the purpose of correcting curvature of field, distortion and aberration.

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

-0.7＜f14/f58＜-0.1。

the first lens element, the second lens element, the third lens element and the fourth lens element are combined to form a first lens assembly with positive refractive power, and the fifth lens element, the sixth lens element, the seventh lens element and the eighth lens element are combined to form a second lens assembly with negative refractive power. The positive and negative refractive powers of the first lens group and the second lens group are matched with each other to achieve the purpose of correcting aberration, curvature of field and distortion. When f14/f58 is more than or equal to-0.1, the negative refractive power of the optical system is insufficient, so that the position phase difference is difficult to correct; when f14/f58 is less than or equal to-0.7, the positive refractive power of the optical system is too large, and distortion correction is difficult, resulting in degradation of the shooting quality.

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

0.20＜Fno/TTL＜0.35；

wherein, Fno is the f-number of the optical system, TTL is the distance from the object-side surface of the first lens element to the imaging surface of the optical system on the optical axis, and the unit of TTL is mm. When the above relationship is satisfied, the optical system has characteristics of a large aperture and miniaturization.

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

fno < 2.0. When the above relation is satisfied, the optical system has the characteristic of large aperture while satisfying miniaturization, so that the optical system has enough light incoming amount, thereby having the capability of obtaining high-quality images under dark environments such as night scenes, starry sky and the like.

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

TTL/Imgh＜1.5；

wherein TTL is a distance on an optical axis from an object-side surface of the first lens element to an imaging surface of the optical system, and Imgh is a half of a diagonal length of an effective pixel area on the imaging surface. TTL/Imgh can determine the size of the optical system, so when the above relationship is satisfied, the optical system can be miniaturized, and in addition, the optical system has a large image height to satisfy the design requirement of 48M (4800 ten thousand pixels).

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

1.0＜TTL/|f|＜1.5；

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 f is an effective focal length of the optical system. When the relation is satisfied, the optical system can effectively balance the aberration generated by the first lens. When TTL/| f |, is less than or equal to 1.0, the optical length of the optical system is too short, so that the sensitivity of the system is increased, and the aberration is difficult to correct; when TTL/| f | > is greater than or equal to 1.5, the optical length of the optical system is too long, which causes the chief ray angle of the light ray entering the imaging surface to be too large, so that the light ray reaching the edge of the imaging surface cannot be imaged on the photosensitive surface, resulting in incomplete imaging information.

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

f/f1≤1.2；

wherein f is the effective focal length of the optical system, and f1 is the effective focal length of the first lens. The optical information obtained by the optical system needs to pass through the first lens, the focal length of the first lens determines the acquisition of object space optical information by the optical system, and when the relation is met, the sensitivity of the optical system can be reduced, the processing difficulty is reduced, and the difficulty in correcting the aberration generated by the first lens is reduced.

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

-0.10＜(R9+R10)/(R9*R10)＜0.25；

wherein R9 is a radius of curvature of an object-side surface of the fourth lens at an optical axis, R10 is a radius of curvature of an image-side surface of the fourth lens at the optical axis, and R9 and R10 are both in mm. When the relation is satisfied, the curvature radii of the object side surface and the image side surface of the fourth lens can be reasonably matched, so that the astigmatism problem of the optical system can be effectively improved, and the forming yield of the fourth lens is improved.

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

0.5＜(R3+R4)/f1＜3.5；

wherein R3 is a radius of curvature of an object-side surface of the first lens at an optical axis, R4 is a radius of curvature of an image-side surface of the first lens at the optical axis, and f1 is an effective focal length of the first lens. When (R3+ R4)/f1 is not less than 3.5, the difficulty of aberration correction of the optical system is increased; when (R3+ R4)/f1 is less than or equal to 0.5, the optical system is not favorable for obtaining object space light information, and a better imaging effect is difficult to obtain.

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

0.8＜R5/R6＜3.5；

wherein R5 is a curvature radius of an object side surface of the second lens at an optical axis, and R6 is a curvature radius of an image side surface of the second lens at the optical axis. The second lens element provides negative refractive power to balance the distortion of the first lens element and correct the aberration of the first lens element. When R5/R6 is not less than 3.5, the distortion correction is too large; when R5/R6 is not more than 0.8, the distortion cannot be corrected.

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

8＜|R7+R8|/|R7-R8|＜48；

wherein R7 is a radius of curvature of an object-side surface of the third lens at an optical axis, and R8 is a radius of curvature of an image-side surface of the third lens at the optical axis. When the relation is met, the curvature radius of the object side surface and the curvature radius of the image side surface of the third lens can be reasonably matched, the incidence angle can be reasonably increased to meet the requirement of the image height of the optical system, meanwhile, the sensitivity of the system is reduced, and the assembly stability is improved.

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

-0.6＜f1/f2＜0.1；

wherein f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens. When the above relation is satisfied, the positional chromatic aberration of the optical system can be effectively corrected.

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

1.8＜(R17*R18)/(R17-R18)＜3；

wherein R17 is a radius of curvature of an object-side surface of the eighth lens element at an optical axis, R18 is a radius of curvature of an image-side surface of the eighth lens element at the optical axis, and R17 and R18 are both in mm. When the relation is satisfied, the curvature radius of the object side surface and the curvature radius of the image side surface of the eighth lens element can be reasonably matched, so that the spherical aberration of the optical system can be effectively corrected, the distortion aberration and the astigmatism can be improved, the system sensitivity can be reduced, and the assembly stability can be improved.

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

0.5＜ΣCT/f＜0.8；

wherein Σ CT is a sum of central thicknesses of the lenses in the optical system, and f is an effective focal length of the optical system. When the above relation is satisfied, the optical system has a more compact structure and an effective focal length adapted to the structure, thereby satisfying a miniaturized design.

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

0.40＜ΣCT/TTL＜0.62；

the sigma-delta CT is the sum of the central thicknesses of the lenses in the optical system, and the TTL is the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis. When the relation is satisfied, the optical system has good assembly stability, and is favorable for miniaturization design.

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

0.20＜ET1/CT1＜0.60；

wherein ET1 is the edge thickness of the first lens and CT1 is the center thickness of the first lens. The optical information obtained by the optical system needs to pass through the first lens, and meanwhile, corresponding aberration, distortion and curvature of field are generated along with the first lens, so that the ratio range of the edge thickness and the center thickness of the first lens is not suitable to be too large, the subsequent aberration is difficult to correct due to the too large ratio, and meanwhile, the large distortion and curvature of field are generated, so that the optical performance requirement cannot be met.

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

0.80＜ET8/CT8＜3.00；

wherein ET8 is an edge thickness of the eighth lens and CT8 is a center thickness of the eighth lens. The eighth lens is a key element for performing final correction on the aberration performance of the optical system, the processing difficulty is relatively high, the ratio of the edge thickness to the center thickness is not too large, and when the relation is met, the eighth lens has good optical performance and forming yield.

An image capturing module includes a photosensitive element and the optical system according to any of the above embodiments, wherein the photosensitive element is disposed on an image side of the optical system.

An electronic device includes the image capturing module of the above embodiment.

Drawings

FIG. 1 is a schematic view of an optical system according to a first embodiment of the present disclosure;

fig. 2 is a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%);

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

fig. 4 is a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%)' of the optical system in the second embodiment;

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

fig. 6 is a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%)' of the optical system in the third embodiment;

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

fig. 8 is a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%)' of the optical system in the fourth embodiment;

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

fig. 10 is a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%);

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

fig. 12 is a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%)' of the optical system in the sixth embodiment;

FIG. 13 is a schematic view of an optical system provided in a seventh embodiment of the present application;

fig. 14 is a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%)' of the optical system in the seventh embodiment;

FIG. 15 is a schematic view of an optical system according to an eighth embodiment of the present application;

fig. 16 is a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%)' of the optical system in the eighth embodiment;

FIG. 17 is a schematic view of an optical system provided in a ninth embodiment of the present application;

fig. 18 is a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%)' of the optical system in the ninth embodiment;

fig. 19 is a schematic view of an optical system provided in a tenth embodiment of the present application;

fig. 20 is a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%)' of the optical system in the tenth embodiment;

FIG. 21 is a schematic view of an optical system provided in an eleventh embodiment of the present application;

fig. 22 is a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%)' of the optical system in the eleventh embodiment;

FIG. 23 is a schematic view of an optical system provided in a twelfth embodiment of the present application;

fig. 24 is a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%)' of the optical system in the twelfth embodiment;

FIG. 25 is a schematic view of an optical system provided in a thirteenth embodiment of the present application;

fig. 26 is a longitudinal spherical aberration diagram (mm), astigmatism diagram (mm), and distortion diagram (%)' of the optical system in the thirteenth embodiment;

fig. 27 is a schematic view of an optical system provided in a fourteenth embodiment of the present application;

fig. 28 is a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%)' of the optical system in the fourteenth embodiment;

fig. 29 is a schematic view of an image capturing module according to an embodiment of the present application;

fig. 30 is a schematic view of an electronic device according to an embodiment of the disclosure.

Detailed Description

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

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

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

The optical system provided by the application can be applied to but not limited to mobile phones, tablet computers, unmanned aerial vehicles, computers and other electronic devices, so that users can obtain high-quality shooting images in dark environments.

Referring to fig. 1, the optical system 100 according to the embodiment of the present application includes, in order from an object side to an image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8.

The first lens L1 includes an object-side surface S1 and an image-side surface S2; the second lens L2 includes an object-side surface S3 and an image-side surface S4; the third lens L3 includes an object-side surface S5 and an image-side surface S6; the fourth lens L4 includes an object-side surface S7 and an image-side surface S8; the fifth lens L5 includes an object-side surface S9 and an image-side surface S10; the sixth lens L6 includes an object-side surface S11 and an image-side surface S12; the seventh lens L7 includes an object-side surface S13 and an image-side surface S14; the eighth lens L8 includes an object-side surface S15 and an image-side surface S16. In addition, the optical system 100 further has an image forming surface S19 on the image side of the eighth lens element L8, and the image forming surface S19 may be a photosensitive surface of a photosensitive element.

The object-side surface S1 of the first lens L1 is convex at the optical axis; the object-side surface S3 of the second lens L2 is convex at the optical axis; the object-side surface S13 of the seventh lens element L7 is convex along the optical axis, and the image-side surface S14 is concave; the object-side surface S15 of the eighth lens element L8 is convex along the optical axis, and the image-side surface S16 is concave along the optical axis.

It should be noted that when a side of the lens is described as being convex at the optical axis (the central region of the side), it can be understood that the region of the side of the lens near the optical axis is convex, and thus the side can also be considered as being convex at the paraxial region; when one side of the lens is described as being concave at the circumference, it is understood that the side is concave in the region near the maximum effective radius. For example, when the side surface is convex at the optical axis and also convex at the circumference, the shape of the side surface from the center (optical axis) to the edge direction may be a pure convex surface; or a convex shape at the center is firstly transited to a concave shape, and then becomes a convex shape near the maximum effective radius. Here, examples are made only to explain the relationship between the optical axis and the circumference, and various shape structures (concave-convex relationship) of the side face are not fully embodied, but other cases can be derived from the above examples.

In some embodiments, the object-side or image-side surface of the lens in the optical system 100 may be aspheric, and the aspheric surface has the following formula:

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, c is the curvature of the aspheric surface vertex (at the optical axis), k is a conic constant, and Ai is the coefficient corresponding to the i-th high-order term in the aspheric surface type formula.

In some embodiments, the object-side surface and the image-side surface of each lens (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) in the optical system 100 are aspheric.

In some embodiments, the material of each lens in the optical system 100 is plastic, and in this case, the plastic lens can reduce the weight of the optical system 100 and reduce the production cost. In other embodiments, the material of each lens in the optical system 100 is glass, and in this case, the optical system 100 can endure higher temperature and has better optical performance. In other embodiments, the first lens L1 is made of glass, and the other lenses are made of plastic, in which case, the first lens L1 closest to the object side can better withstand the influence of the ambient temperature on the object side, and the optical system 100 can keep the production cost low because the other lenses are made of plastic. It should be noted that, according to actual requirements, the material of each lens in the optical system 100 may be any one of plastic and glass.

In some embodiments, an optical stop STO is disposed in the optical system 100, and the optical stop STO may be disposed on the object side of the first lens L1. It should be noted that, when the stop STO is disposed on the object side of the first lens L1 or the optical system 100 is described as having the stop STO, the first lens L1, the second lens L2, and other elements disposed in order from the object side to the image side, the projection of the stop STO on the optical axis of the first lens L1 may overlap with the projection of the first lens L1 on the optical axis, or may not overlap with the projection of the first lens L1.

In some embodiments, the image side of the eighth lens L8 is further provided with an infrared cut filter L9, and the infrared cut filter L9 includes an object side surface S17 and an image side surface S18. The infrared cut-off filter L9 can filter infrared light, prevent the infrared light from passing through and reaching the photosensitive element, and prevent the infrared interference light from being received by the photosensitive element and affecting normal imaging, thereby improving the imaging quality of the optical system 100. In some embodiments, the ir-cut filter L9 may be assembled with the photosensitive elements and assembled with the photosensitive elements on the image side of the optical system 100, or the ir-cut filter may be directly disposed in the optical system 100 to be assembled with the lenses.

In some embodiments, the optical system 100 may further include any elements, such as a mirror, an aperture, a filter, a cover glass, and a photosensitive element, in addition to the lens with refractive power, in order to make the parameter definition and effect description of the present application clearer and more complete.

In some embodiments, the optical system 100 satisfies the following relationship: TTL/L is more than 1 and less than 2.5; wherein, TTL is the distance on the optical axis from the object-side surface S1 of the first lens element L1 to the image plane S19 of the optical system 100, and L is the effective aperture diameter of the stop STO. TTL/L can be 1.76, 1.78, 1.80, 1.81, 1.85, 1.90, 1.95, 2.10, 2.20, 2.25, or 2.30.

When the above relationship is satisfied, the optical system 100 has the characteristics of a large aperture and a large aperture in performance, has the capability of obtaining a high-quality image in dark light environments such as cloudy days, night scenes, starry sky and the like, and has high definition; in addition, the optical system 100 has a characteristic of miniaturization in structure.

In some embodiments, the optical system 100 satisfies the following relationship: f14 > 0; f58 < 0; wherein f14 is a combined focal length of the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4, and f58 is a combined focal length of the fifth lens L5, the sixth lens L6, the seventh lens L7 and the eighth lens L8. f14 may be 5.20, 5.22, 5.25, 5.30, 5.35, 5.40, 5.50, 5.60, 5.70, 5.80, 5.85, 5.90, or 5.92; f58 can be-30.00, -28.00, -25.00, -23.00, -20.00, -15.00, -14.50, -14.00, -10.00, -9.50, -9.30, -9.10, -8.50, -8.40, or-8.30. The units of f14 and f58 are both mm. When the above relationship is satisfied, the first lens element L1, the second lens element L2, the third lens element L3 and the fourth lens element L4 form a first lens group with positive refractive power, and the fifth lens element L5, the sixth lens element L6, the seventh lens element L7 and the eighth lens element L8 form a second lens group with negative refractive power. The positive and negative refractive powers of the first lens group and the second lens group are matched with each other to achieve the purpose of correcting curvature of field, distortion and aberration.

In some embodiments, the optical system 100 satisfies the following relationship: -0.7 < f14/f58 < -0.1; the first lens element L1, the second lens element L2, the third lens element L3 and the fourth lens element L4 form a first lens group with positive refractive power, and the fifth lens element L5, the sixth lens element L6, the seventh lens element L7 and the eighth lens element L8 form a second lens group with negative refractive power. f14/f58 can be-0.60, -0.57, -0.50, -0.45, -0.37, -0.35, -0.30, -0.25, -0.22, -0.20, or-0.19. The first lens group and the second lens group can cooperate with each other for the purpose of correcting aberrations, curvature of field, and distortion. When f14/f58 is not less than or equal to-0.1, the negative refractive power of the optical system 100 is insufficient, which makes the correction of the position phase difference difficult; when f14/f58 is less than or equal to-0.7, the positive refractive power of the optical system 100 is too large, and distortion correction is difficult, resulting in degradation of the shooting quality.

In some embodiments, the optical system 100 satisfies the following relationship: Fno/TTL is more than 0.20 and less than 0.35;

where Fno is an f-number of the optical system 100, TTL is a distance on an optical axis from the object-side surface S1 of the first lens element L1 to the image plane S19 of the optical system 100, and the unit of TTL is mm. Fno/TTL can be 0.24, 0.250, 0.28, 0.30, or 0.32. When the above relationship is satisfied, the optical system 100 has characteristics of a large aperture and a small size.

In some embodiments, the optical system 100 satisfies the following relationship: fno < 2.0. The FNO can be 1.40, 1.41, 1.42, 1.45, 1.47, 1.48, 1.57, 1.65, 1.70, 1.75, 1.80, 1.84, 1.86, or 1.87. When the above relationship is satisfied, the optical system 100 has a large aperture characteristic while satisfying miniaturization, and the optical system 100 has a sufficient light incident amount, thereby having a capability of obtaining a high-quality image in dark environments such as a night scene, a starry sky, and the like.

In some embodiments, the optical system 100 satisfies the following relationship: TTL/Imgh is less than 1.5; wherein TTL is an axial distance from the object-side surface S1 of the first lens element L1 to the image plane S19 of the optical system 100, and Imgh is half of a diagonal length of the effective pixel area on the image plane S19. TTL/Imgh can be 1.45, 4.46, 1.47, or 1.48. Since TTL/Imgh can determine the size of the optical system 100, the optical system 100 can be miniaturized if the above relationship is satisfied, and the optical system 100 has a large image height to satisfy the 48M design requirement.

In some embodiments, the optical system 100 satisfies the following relationship: TTL/| f | < 1.0 < 1.5; wherein, TTL is an axial distance from the object-side surface S1 of the first lens element L1 to the image plane S19 of the optical system 100, and f is an effective focal length of the optical system 100. TTL/| f | can be 1.21, 1.22, 1.23, or 1.24. When the above relationship is satisfied, the optical system 100 can effectively balance the aberration generated by the first lens L1. When TTL/| f |, is less than or equal to 1.0, the optical length of the optical system 100 is too short, so that the system sensitivity is increased, and the aberration correction is difficult; when TTL/| f | ≧ 1.5, the optical length of the optical system 100 is too long, which causes the chief ray angle of the light entering the imaging plane S19 to be too large, so that the light reaching the edge of the imaging plane S19 cannot be imaged on the photosensitive surface, resulting in incomplete imaging information.

In some embodiments, the optical system 100 satisfies the following relationship: f/f1 is less than or equal to 1.2; where f is the effective focal length of the optical system 100, and f1 is the effective focal length of the first lens L1. f/f1 may be 0.70, 0.73, 0.75, 0.78, 0.85, 0.92, 0.93, 0.94, 0.97, 1.00, 1.02, 1.04, or 1.08. The optical information obtained by the optical system 100 needs to pass through the first lens L1, and the focal length of the first lens L1 determines the acquisition of the object space optical information by the optical system 100, so that when the above relationship is satisfied, the sensitivity of the optical system 100 can be reduced, the difficulty of the processing process can be reduced, and the difficulty of correcting the aberration generated by the first lens L1 can be reduced.

In some embodiments, the optical system 100 satisfies the following relationship: -0.10 < (R9+ R10)/(R9 × R10) < 0.25; wherein R9 is a radius of curvature of the object-side surface S7 of the fourth lens L4 at the optical axis, R10 is a radius of curvature of the image-side surface S8 of the fourth lens L4 at the optical axis, and R9 and R10 are both in mm. (R9+ R10)/(R9 × R10) may be-0.07, -0.06, -0.05, 0.10, 0.15, 0.20 or 0.21. When the above relationship is satisfied, the curvature radii of the object-side surface S7 and the image-side surface S8 of the fourth lens element L4 can be reasonably matched, so that the astigmatism problem of the optical system 100 can be effectively improved, and the molding yield of the fourth lens element L4 can be improved.

In some embodiments, the optical system 100 satisfies the following relationship: 0.5 < (R3+ R4)/f1 < 3.5; wherein R3 is the radius of curvature of the object-side surface S1 of the first lens element L1 at the optical axis, R4 is the radius of curvature of the image-side surface S2 of the first lens element L1 at the optical axis, and f1 is the effective focal length of the first lens element L1. (R3+ R4)/f1 may be 0.88, 0.90, 0.92, 1.00, 1.30, 1.70, 2.00, 2.55, 2.60, 2.70, 2.90, 3.00, 3.10, 3.15, or 3.20. When (R3+ R4)/f1 is not less than 3.5, the difficulty of aberration correction of the optical system 100 is increased; when (R3+ R4)/f1 is less than or equal to 0.5, it is not favorable for the optical system 100 to acquire the object space light information, and it is difficult to obtain a better imaging effect.

In some embodiments, the optical system 100 satisfies the following relationship: R5/R6 is more than 0.8 and less than 3.5; wherein R5 is a radius of curvature of the object-side surface S3 of the second lens L2 at the optical axis, and R6 is a radius of curvature of the image-side surface S4 of the second lens L2 at the optical axis. The second lens element L2 provides negative refractive power to balance the distortion of the first lens element L1 and correct the aberration of the first lens element L1. R5/R6 can be 1.00, 1.10, 1.20, 1.50, 1.80, 2.00, 2.10, 2.20, 2.30, 2.43, 2.45, 2.50, 2.60, 2.70, 2.80, 2.85, or 2.88. When R5/R6 is not less than 3.5, the distortion correction is too large; when R5/R6 is not more than 0.8, the distortion cannot be corrected.

In some embodiments, the optical system 100 satisfies the following relationship: 8 < | R7+ R8|/| R7-R8| < 48; wherein R7 is a radius of curvature of the object-side surface S5 of the third lens element L3 at the optical axis, and R8 is a radius of curvature of the image-side surface S6 of the third lens element L3 at the optical axis. The | R7+ R8|/| R7-R8| can be 10.00, 11.00, 15.00, 20.00, 25.00, 35.00, 43.00, or 45.00. When the above relationship is satisfied, the curvature radius of the object-side surface S5 and the curvature radius of the image-side surface S6 of the third lens L3 can be reasonably matched, the incident angle can be reasonably increased to satisfy the requirement of the image height of the optical system 100, and at the same time, the system sensitivity is reduced, and the assembly stability is improved.

In some embodiments, the optical system 100 satisfies the following relationship: -0.6 < f1/f2 < 0.1; where f1 is the effective focal length of the first lens L1, and f2 is the effective focal length of the second lens L2. f1/f2 can be-0.55, -0.54, -0.50, -0.49, -0.47, -0.46, -0.35, -0.30, -0.10, or 0.01. When the above relationship is satisfied, the positional chromatic aberration of the optical system 100 can be effectively corrected.

In some embodiments, the optical system 100 satisfies the following relationship: 1.8 < (R17R 18)/(R17-R18) < 3; wherein R17 is a radius of curvature of the object-side surface S15 of the eighth lens element L8 on the optical axis, R18 is a radius of curvature of the image-side surface S16 of the eighth lens element L8 on the optical axis, and the units of R17 and R18 are both mm. (R17 × R18)/(R17-R18) may be 2.00, 2.10, 2.20, 2.56, 2.58, 2.60, 2.65, 2.70, 2.75, 2.80, 2.85 or 2.87. When the above relationship is satisfied, the curvature radius of the object-side surface S15 and the curvature radius of the image-side surface S16 of the eighth lens element L8 can be reasonably matched, so that the spherical aberration of the optical system 100 can be effectively corrected, the distortion aberration and astigmatism can be improved, the system sensitivity can be reduced, and the assembly stability can be improved.

In some embodiments, the optical system 100 satisfies the following relationship: sigma CT/f is more than 0.5 and less than 0.8; where Σ CT is the sum of the central thicknesses of the lenses in the optical system 100, and f is the effective focal length of the optical system 100. Σ CT/f may be 0.70, 0.71, 0.72, 0.73, 0.74, or 0.75. When the above relationship is satisfied, the optical system 100 has a more compact structure and an effective focal length adapted to the structure, thereby satisfying a miniaturized design.

In some embodiments, the optical system 100 satisfies the following relationship: sigma CT/TTL is more than 0.40 and less than 0.62; where Σ CT is the sum of the central thicknesses of the lenses in the optical system 100, and TTL is the distance on the optical axis from the object-side surface S1 of the first lens L1 to the image plane S19 of the optical system 100. The Σ CT/TTL may be 0.57, 0.58, 0.59, 0.60, or 0.61. When the above relationship is satisfied, the optical system 100 has good assembly stability, which is advantageous for miniaturization design.

In some embodiments, the optical system 100 satisfies the following relationship: 0.20 < ET1/CT1 < 0.60; ET1 is the edge thickness of the first lens L1 (the thickness of the first lens L1 at the maximum effective radius), and CT1 is the center thickness of the first lens L1. ET1/CT1 may be 0.26, 0.27, 0.28, 0.30, 0.35, 0.39, 0.42, 0.46, 0.49, 0.53, 0.55, or 0.56. The optical information obtained by the optical system 100 needs to pass through the first lens L1, and meanwhile, corresponding aberration, distortion and curvature of field are also generated along with the first lens L1, so the ratio range of the edge thickness to the center thickness of the first lens L1 is not suitable to be too large, the ratio is too large, which causes difficulty in subsequent aberration correction, and simultaneously generates large distortion and curvature of field, which cannot meet the optical performance requirements, and when the above relation is met, a good optical system 100 can be obtained, so that the aberration, distortion and curvature of field of the system are balanced, and the requirement of high-quality shooting is met.

In some embodiments, the optical system 100 satisfies the following relationship: 0.80 < ET8/CT8 < 3.00; ET8 is the edge thickness of the eighth lens L8 (the thickness of the eighth lens L8 at the maximum effective radius), and CT8 is the center thickness of the eighth lens L8. ET8/CT8 may be 0.88, 0.90, 0.92, 0.95, 1.00, 1.05, 1.10, 1.13, 1.15, 1.80, 2.10, 2.20, 2.25, or 2.27. The eighth lens L8 is a key element for performing final correction on the aberration performance of the optical system 100, and has relatively high processing difficulty, and the ratio of the edge thickness to the center thickness should not be too large, so that the eighth lens L8 has good optical performance and molding yield when the above relationship is satisfied.

Specific embodiments that may be suitable for use in the above-described optical system 100 are further described below with reference to the accompanying drawings. It should be noted, however, that the drawings are designed solely for reference and do not necessarily represent actual figures for the corresponding embodiments.

First embodiment

Referring to fig. 1, in the first embodiment, the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with 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 positive refractive power, a seventh lens element L7 with negative refractive power, and an eighth lens element L8 with negative refractive power. Fig. 2 includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the optical system 100 in the first embodiment, wherein the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength. The reference wavelength in each example was 555 nm.

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

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

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

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

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

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

The object-side surface S13 of the seventh lens element L7 is convex paraxially, and the image-side surface S14 of the seventh lens element L7 is concave paraxially; the object-side surface S13 of the seventh lens element L7 is concave at the circumference, and the image-side surface S14 of the seventh lens element L7 is convex at the circumference.

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

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 surfaces, the aspheric surface design can effectively solve the problem of distortion of the view, and the lenses can achieve excellent optical effects under the conditions of small size and thinness, so that the optical system 100 has a smaller volume.

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 some embodiments, an infrared cut filter L9 is further disposed on the image side of the eighth lens element L8 to filter infrared light, so as to prevent the photosensitive element from receiving infrared light and affecting normal imaging.

In the first embodiment, the optical system 100 satisfies the relationship: TTL/L is 1.74; wherein, TTL is the distance on the optical axis from the object-side surface S1 of the first lens element L1 to the image plane S19 of the optical system 100, and L is the effective aperture diameter of the stop STO. When the above relationship is satisfied, the optical system 100 has a characteristic of a large aperture and a large aperture in performance, has a capability of obtaining a high-quality image in a dark light environment such as a cloudy day, a night scene, and a starry sky, has high definition of image quality, and has a characteristic of miniaturization in structure.

The optical system 100 satisfies the relationship: f14 ═ 5.51; f58 ═ 21.71; wherein f14 is a combined focal length of the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4, and f58 is a combined focal length of the fifth lens L5, the sixth lens L6, the seventh lens L7 and the eighth lens L8. The units of f14 and f58 are both mm. When the above relationship is satisfied, the first lens element L1, the second lens element L2, the third lens element L3 and the fourth lens element L4 form a first lens group with positive refractive power, and the fifth lens element L5, the sixth lens element L6, the seventh lens element L7 and the eighth lens element L8 form a second lens group with negative refractive power. The positive and negative refractive powers of the first lens group and the second lens group are matched with each other to achieve the purpose of correcting curvature of field, distortion and aberration.

The optical system 100 satisfies the relationship: f14/f58 is-0.25. The first lens element L1, the second lens element L2, the third lens element L3 and the fourth lens element L4 form a first lens group with positive refractive power, and the fifth lens element L5, the sixth lens element L6, the seventh lens element L7 and the eighth lens element L8 form a second lens group with negative refractive power. The first lens group and the second lens group can cooperate with each other for the purpose of correcting aberrations, curvature of field, and distortion.

The optical system 100 satisfies the relationship: Fno/TTL ═ 0.237; where Fno is an f-number of the optical system 100, TTL is a distance on an optical axis from the object-side surface S1 of the first lens element L1 to the image plane S19 of the optical system 100, and the unit of TTL is mm. When the above relationship is satisfied, the optical system 100 has characteristics of a large aperture and a small size.

The optical system 100 satisfies the relationship: fno 1.397. When the above relationship is satisfied, the optical system 100 has a large aperture characteristic while satisfying miniaturization, and the optical system 100 has a sufficient light incident amount, thereby having a capability of obtaining a high-quality image in dark environments such as a night scene, a starry sky, and the like.

The optical system 100 satisfies the relationship: TTL/Imgh is 1.475; wherein TTL is an axial distance from the object-side surface S1 of the first lens element L1 to the image plane S19 of the optical system 100, and Imgh is half of a diagonal length of the effective pixel area on the image plane S19. Since TTL/Imgh can determine the size of the optical system 100, the optical system 100 can be miniaturized if the above relationship is satisfied, and the optical system 100 has a large image height to satisfy the 48M design requirement.

The optical system 100 satisfies the relationship: TTL/| f |, 1.245; wherein, TTL is an axial distance from the object-side surface S1 of the first lens element L1 to the image plane S19 of the optical system 100, and f is an effective focal length of the optical system 100. When TTL/| f | is too small, the optical length of the optical system 100 is too short, which results in increased system sensitivity and difficulty in aberration correction; when TTL/| f | is too large, the optical length of the optical system 100 is too long, which results in too large angle of the chief ray of the light entering the imaging plane S19, so that the light reaching the edge of the imaging plane S19 cannot be imaged on the photosensitive surface, resulting in incomplete imaging information.

The optical system 100 satisfies the relationship: f/f1 is 1.05; where f is the effective focal length of the optical system 100, and f1 is the effective focal length of the first lens L1. The optical information obtained by the optical system 100 needs to pass through the first lens L1, and the focal length of the first lens L1 determines the acquisition of the object space optical information by the optical system 100, so that when the above relationship is satisfied, the sensitivity of the optical system 100 can be reduced, the difficulty of the processing process can be reduced, and the difficulty of correcting the aberration generated by the first lens L1 can be reduced.

The optical system 100 satisfies the relationship: (R9+ R10)/(R9 × R10) ═ 0.13; wherein R9 is a radius of curvature of the object-side surface S7 of the fourth lens L4 at the optical axis, R10 is a radius of curvature of the image-side surface S8 of the fourth lens L4 at the optical axis, and R9 and R10 are both in mm. When the above relationship is satisfied, the curvature radii of the object-side surface S7 and the image-side surface S8 of the fourth lens element L4 can be reasonably matched, so that the astigmatism problem of the optical system 100 can be effectively improved, and the molding yield of the fourth lens element L4 can be improved.

The optical system 100 satisfies the relationship: (R3+ R4)/f1 ═ 2.73; wherein R3 is the radius of curvature of the object-side surface S1 of the first lens element L1 at the optical axis, R4 is the radius of curvature of the image-side surface S2 of the first lens element L1 at the optical axis, and f1 is the effective focal length of the first lens element L1. When the value of (R3+ R4)/f1 is too large, the difficulty of aberration correction of the optical system 100 is increased; when (R3+ R4)/f1 is too small, it is not favorable for the optical system 100 to acquire object space optical information, and it is difficult to obtain a good imaging effect.

The optical system 100 satisfies the relationship: R5/R6 ═ 2.86; wherein R5 is a radius of curvature of the object-side surface S3 of the second lens L2 at the optical axis, and R6 is a radius of curvature of the image-side surface S4 of the second lens L2 at the optical axis. The second lens element L2 provides negative refractive power to balance the distortion of the first lens element L1 and correct the aberration of the first lens element L1.

The optical system 100 satisfies the relationship: r7+ R8/| R7-R8| ═ 13.81; wherein R7 is a radius of curvature of the object-side surface S5 of the third lens element L3 at the optical axis, and R8 is a radius of curvature of the image-side surface S6 of the third lens element L3 at the optical axis. When the above relationship is satisfied, the curvature radius of the object-side surface S5 and the curvature radius of the image-side surface S6 of the third lens L3 can be reasonably matched, the incident angle can be reasonably increased to satisfy the requirement of the image height of the optical system 100, and at the same time, the system sensitivity is reduced, and the assembly stability is improved.

The optical system 100 satisfies the relationship: f1/f2 is-0.56; where f1 is the effective focal length of the first lens L1, and f2 is the effective focal length of the second lens L2. When the above relationship is satisfied, the positional chromatic aberration of the optical system 100 can be effectively corrected.

The optical system 100 satisfies the relationship: (R17 × R18)/(R17-R18) ═ 2.55; wherein R17 is a radius of curvature of the object-side surface S17 of the eighth lens element L8 on the optical axis, R18 is a radius of curvature of the image-side surface S16 of the eighth lens element L8 on the optical axis, and the units of R17 and R18 are both mm. When the above relationship is satisfied, the curvature radius of the object-side surface S15 and the curvature radius of the image-side surface S16 of the eighth lens element L8 can be reasonably matched, so that the spherical aberration of the optical system 100 can be effectively corrected, the distortion aberration and astigmatism can be improved, the system sensitivity can be reduced, and the assembly stability can be improved.

The optical system 100 satisfies the relationship: sigma CT/f is 0.74; where Σ CT is the sum of the central thicknesses of the lenses in the optical system 100, and f is the effective focal length of the optical system 100. When the above relationship is satisfied, the optical system 100 has a more compact structure and an effective focal length adapted to the structure, thereby satisfying a miniaturized design.

The optical system 100 satisfies the relationship: sigma CT/TTL is 0.59; where Σ CT is the sum of the central thicknesses of the lenses in the optical system 100, and TTL is the distance on the optical axis from the object-side surface S1 of the first lens L1 to the image plane S19 of the optical system 100. When the above relationship is satisfied, the optical system 100 has good assembly stability, which is advantageous for miniaturization design.

The optical system 100 satisfies the relationship: ET1/CT1 ═ 0.265; ET1 is the edge thickness of the first lens L1 (the thickness of the first lens L1 at the maximum effective radius), and CT1 is the center thickness of the first lens L1. The optical information obtained by the optical system 100 needs to pass through the first lens L1, and meanwhile, corresponding aberration, distortion and curvature of field are also generated along with the first lens L1, so the ratio range of the edge thickness to the center thickness of the first lens L1 is not suitable to be too large, the ratio is too large, which causes difficulty in subsequent aberration correction, and simultaneously generates large distortion and curvature of field, which cannot meet the optical performance requirements, and when the above relation is met, a good optical system 100 can be obtained, so that the aberration, distortion and curvature of field of the system are balanced, and the requirement of high-quality shooting is met.

The optical system 100 satisfies the relationship: ET8/CT8 ═ 0.86; ET8 is the edge thickness of the eighth lens L8 (the thickness of the eighth lens L8 at the maximum effective radius), and CT8 is the center thickness of the eighth lens L8. The eighth lens L8 is a key element for performing final correction on the aberration performance of the optical system 100, and has relatively high processing difficulty, and the ratio of the edge thickness to the center thickness should not be too large, so that the eighth lens L8 has good optical performance and molding yield when the above relationship is satisfied.

In addition, the parameters of the optical system 100 are given by table 1 and table 2. The optical system 100 has elements from the object plane (object side) to the image plane S19 (image plane in table 1) arranged in the order of the elements from top to bottom in table 1. Surface numbers 3 and 4 in table 1 are the object-side surface S1 and the image-side surface S2 of the first lens L1, respectively, that is, the surface with the smaller surface number is the object-side surface and the surface with the larger surface number is the image-side surface in the same lens. The radius Y is the curvature radius of the object side surface or the image side surface of the corresponding surface serial number at the paraxial position. The first value in the "thickness" parameter list of the first lens element L1 is the thickness of the lens element along the optical axis, and the second value is the distance from the image-side surface of the lens element to the object-side surface of the subsequent lens element along the optical axis. The value corresponding to the plane number 20 in the "thickness" parameter of the ir-cut filter L9 is the distance from the image side surface S18 to the image plane S19 of the ir-cut filter L9. K in table 2 is a conic constant, and Ai is a coefficient corresponding to the i-th high-order term in the aspherical surface type formula. Generally, the image plane in table 1 is the photosensitive surface of the photosensitive element.

In addition, the refractive index and the focal length of each lens are numerical values at a reference wavelength. The relational expression is calculated based on the lens parameters (e.g., data in Table 1) and the profile parameters (e.g., data in Table 2).

In the first embodiment, the effective focal length f of the optical system 100 is 4.74mm, the f-number FNO is 1.397, the maximum field angle (diagonal angle of view) FOV is 80.39 degrees (deg.), the distance TTL from the object-side surface S1 of the first lens L1 to the imaging surface S19 on the optical axis is 5.9mm, and half of the diagonal length Imgh of the effective pixel area on the imaging surface is 4.0 mm.

TABLE 1

TABLE 2

Second embodiment

Referring to fig. 3, in the second embodiment, the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with positive 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 negative refractive power, and an eighth lens element L8 with negative refractive power. Fig. 4 includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the optical system 100 in the second embodiment, in which the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength, and the reference wavelength is 555 nm.

In the second embodiment, the effective focal length f of the optical system 100 is 4.75mm, the f-number FNO is 1.397, the maximum field angle (diagonal angle of view) FOV is 80.33 degrees (deg.), and the distance TTL from the object-side surface S1 of the first lens L1 to the image plane S19 on the optical axis is 5.9 mm.

The parameters of the optical system 100 are given in tables 3 and 4, and the definitions of the parameters can be derived from the first embodiment, which is not described herein.

TABLE 3

TABLE 4

Based on the above provided parameter information, the following relationships can be deduced:

third embodiment

Referring to fig. 5, in the third embodiment, the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with negative refractive power, a sixth lens element L6 with positive refractive power, a seventh lens element L7 with negative refractive power, and an eighth lens element L8 with negative refractive power. Fig. 6 includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the optical system 100 in the third embodiment, in which the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength, and the reference wavelength is 555 nm.

In the third embodiment, the effective focal length f of the optical system 100 is 4.76mm, the f-number FNO is 1.397, the maximum field angle (diagonal angle of view) FOV is 80.40 degrees (deg.), and the distance TTL from the object-side surface S1 of the first lens L1 to the image plane S19 on the optical axis is 5.9 mm.

The parameters of the optical system 100 are given in tables 5 and 6, and the definitions of the parameters can be derived from the first embodiment, which is not described herein.

TABLE 5

TABLE 6

fourth embodiment

Referring to fig. 7, in the fourth embodiment, the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with 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 positive refractive power, a seventh lens element L7 with negative refractive power, and an eighth lens element L8 with negative refractive power. Fig. 8 includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the optical system 100 in the fourth embodiment, in which the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength, and the reference wavelength is 555 nm.

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

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

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

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

In the fourth embodiment, the effective focal length f of the optical system 100 is 4.79mm, the f-number FNO is 1.481, the maximum field angle (diagonal angle of view) FOV is 79.84 degrees (deg.), and the distance TTL from the object-side surface S1 of the first lens L1 to the image plane S19 on the optical axis is 5.9 mm.

The parameters of the optical system 100 are given in tables 7 and 8, and the definitions of the parameters can be derived from the first embodiment, which is not described herein.

TABLE 7

TABLE 8

fifth embodiment

Referring to fig. 9, in the fifth embodiment, the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with 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 positive refractive power, a seventh lens element L7 with negative refractive power, and an eighth lens element L8 with negative refractive power. Fig. 10 includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the optical system 100 in the fifth embodiment, in which the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength, and the reference wavelength is 555 nm.

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

In the fifth embodiment, the effective focal length f of the optical system 100 is 4.78mm, the f-number FNO is 1.481, the maximum field angle (diagonal angle of view) FOV is 79.95 degrees (deg.), and the distance TTL from the object-side surface S1 of the first lens L1 to the image plane S19 on the optical axis is 5.9 mm.

The parameters of the optical system 100 are given in tables 9 and 10, and the definitions of the parameters can be derived from the first embodiment, which is not described herein.

TABLE 9

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sixth embodiment

Referring to fig. 11, in the sixth embodiment, the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with 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 negative refractive power, and an eighth lens element L8 with negative refractive power. Fig. 12 includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the optical system 100 in the sixth embodiment, in which the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength, and the reference wavelength is 555 nm.

In the sixth embodiment, the effective focal length f of the optical system 100 is 4.88mm, the f-number FNO is 1.397, the maximum field angle (diagonal angle of view) FOV is 78.21 degrees (deg.), and the distance TTL from the object-side surface S1 of the first lens L1 to the image plane S19 on the optical axis is 6.07 mm.

The parameters of the optical system 100 are given in tables 11 and 12, and the definitions of the parameters can be derived from the first embodiment, which is not described herein.

TABLE 11

TABLE 12

seventh embodiment

Referring to fig. 13, in the seventh embodiment, the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with 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. 14 includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the optical system 100 in the seventh embodiment, in which the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength, and the reference wavelength is 555 nm.

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

In the seventh embodiment, the effective focal length f of the optical system 100 is 4.79mm, the f-number FNO is 1.397, the maximum field angle (diagonal angle of view) FOV is 80 degrees (deg.), and the distance TTL from the object-side surface S1 of the first lens L1 to the image plane S19 on the optical axis is 5.9 mm.

The parameters of the optical system 100 are given in tables 13 and 14, and the definitions of the parameters can be derived from the first embodiment, which is not described herein.

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TABLE 14

eighth embodiment

Referring to fig. 15, in the eighth embodiment, the optical system 100 includes, in order from the object side to the image side, a stop STO, the first lens element L1 with positive refractive power, the second lens element L2 with positive refractive power, the third lens element L3 with negative refractive power, the fourth lens element L4 with positive refractive power, the fifth lens element L5 with positive refractive power, the sixth lens element L6 with positive refractive power, the seventh lens element L7 with negative refractive power, and the eighth lens element L8 with negative refractive power. Fig. 16 includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the optical system 100 in the eighth embodiment, in which the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength, and the reference wavelength is 555 nm.

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

In the eighth embodiment, the effective focal length f of the optical system 100 is 4.81mm, the f-number FNO is 1.6, the maximum field angle (diagonal angle of view) FOV is 80 degrees (deg.), and the distance TTL from the object-side surface S1 of the first lens L1 to the image plane S19 on the optical axis is 5.92 mm.

The parameters of the optical system 100 are given in tables 15 and 16, and the definitions of the parameters can be derived from the first embodiment, which is not described herein.

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TABLE 16

ninth embodiment

Referring to fig. 17, in the ninth embodiment, the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with 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. 18 includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the optical system 100 in the ninth embodiment, in which the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength, and the reference wavelength is 555 nm.

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

In the ninth embodiment, the effective focal length f of the optical system 100 is 4.9mm, the f-number FNO is 1.8, the maximum field angle (diagonal angle of view) FOV is 78.66 degrees (deg.), and the distance TTL from the object-side surface S1 of the first lens L1 to the image plane S19 on the optical axis is 5.9 mm.

The parameters of the optical system 100 are given in tables 17 and 18, and the definitions of the parameters can be derived from the first embodiment, which is not described herein.

TABLE 17

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tenth embodiment

Referring to fig. 19, in the tenth embodiment, the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with 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. 20 includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the optical system 100 in the tenth embodiment, in which the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength, and the reference wavelength is 555 nm.

In the tenth embodiment, the effective focal length f of the optical system 100 is 4.79mm, the f-number FNO is 1.55, the maximum field angle (diagonal angle of view) FOV is 80 degrees (deg.), and the distance TTL from the object-side surface S1 of the first lens L1 to the image plane S19 on the optical axis is 5.9 mm.

The parameters of the optical system 100 are given in tables 19 and 20, and the definitions of the parameters can be derived from the first embodiment, which is not described herein.

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eleventh embodiment

Referring to fig. 21, in the eleventh embodiment, the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with 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. 22 includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the optical system 100 in the eleventh embodiment, in which the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength, and the reference wavelength is 555 nm.

In the eleventh embodiment, the effective focal length f of the optical system 100 is 4.79mm, the f-number FNO is 1.65, the maximum field angle (diagonal angle of view) FOV is 80 degrees (deg.), and the distance TTL from the object-side surface S1 of the first lens L1 to the image plane S19 on the optical axis is 5.9 mm.

The parameters of the optical system 100 are given in tables 21 and 22, and the definitions of the parameters can be derived from the first embodiment, which is not described herein.

TABLE 21

TABLE 22

twelfth embodiment

Referring to fig. 23, in the twelfth embodiment, the optical system 100 includes, in order from the object side to the image side, a stop STO, the first lens element L1 with positive refractive power, the second lens element L2 with negative refractive power, the third lens element L3 with negative refractive power, the fourth lens element L4 with positive refractive power, the fifth lens element L5 with positive refractive power, the sixth lens element L6 with positive refractive power, the seventh lens element L7 with negative refractive power, and the eighth lens element L8 with negative refractive power. Fig. 24 includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the optical system 100 in the twelfth embodiment, in which the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength, and the reference wavelength is 555 nm.

In the twelfth embodiment, the effective focal length f of the optical system 100 is 4.83mm, the f-number FNO is 1.88, the maximum field angle (diagonal angle of view) FOV is 79.5 degrees (deg.), and the distance TTL from the object-side surface S1 of the first lens L1 to the image plane S19 on the optical axis is 5.9 mm.

The parameters of the optical system 100 are given in tables 23 and 24, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

TABLE 23

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thirteenth embodiment

Referring to fig. 25, in the thirteenth embodiment, the optical system 100 includes, in order from the object side to the image side, a stop STO, the first lens element L1 with positive refractive power, the second lens element L2 with negative refractive power, the third lens element L3 with negative refractive power, the fourth lens element L4 with positive refractive power, the fifth lens element L5 with positive refractive power, the sixth lens element L6 with positive refractive power, the seventh lens element L7 with positive refractive power, and the eighth lens element L8 with negative refractive power. Fig. 26 includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the optical system 100 in the thirteenth embodiment, in which the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength, and the reference wavelength is 555 nm.

In the thirteenth embodiment, the effective focal length f of the optical system 100 is 4.8mm, the f-number FNO is 1.88, the maximum field angle (diagonal angle) FOV is 79.8 degrees (deg.), and the distance TTL from the object-side surface S1 of the first lens L1 to the image plane S19 on the optical axis is 5.9 mm.

The parameters of the optical system 100 are given in tables 25 and 26, and the definitions of the parameters can be derived from the first embodiment, which is not described herein.

TABLE 25

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fourteenth embodiment

Referring to fig. 27, in the fourteenth embodiment, the optical system 100 includes, in order from an object side to an image side, a stop STO, the first lens element L1 with positive refractive power, the second lens element L2 with negative refractive power, the third lens element L3 with negative refractive power, the fourth lens element L4 with positive refractive power, the fifth lens element L5 with positive refractive power, the sixth lens element L6 with negative refractive power, the seventh lens element L7 with positive refractive power, and the eighth lens element L8 with negative refractive power. Fig. 28 includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the optical system 100 in the fourteenth embodiment, in which the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength, and the reference wavelength is 555 nm.

In the fourteenth embodiment, the effective focal length f of the optical system 100 is 4.85mm, the f-number FNO is 1.8, the maximum field angle (diagonal angle) FOV is 79.2 degrees (deg.), and the distance TTL from the object-side surface S1 of the first lens L1 to the image plane S19 on the optical axis is 5.9 mm.

The parameters of the optical system 100 are given in tables 27 and 28, and the definitions of the parameters can be derived from the first embodiment, which is not described herein.

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referring to fig. 29, in some embodiments, the image side of the optical system is equipped with a photosensitive element 210, which may be a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), to form the image capturing module 200. It is to be noted that the image forming surface S19 in the above embodiments may be understood as a photosensitive surface of the photosensitive element 210.

In some embodiments, the photosensitive element 210 is disposed relatively fixedly on the image side of the optical system, and the image capturing module 200 is a fixed focus module. In other embodiments, the focusing function is achieved by configuring the voice coil motor to enable the photosensitive element 210 to move relative to each lens in the optical system 100.

Referring to fig. 30, in some embodiments, the image capturing module 200 may be applied to, but not limited to, an electronic device 30 such as a smart phone, a tablet computer, a PDA (Personal Digital Assistant), a drone, a computer, and the like, so as to enable a user to obtain a high-quality photographed image in a dark environment. The electronic device 30 comprises any mobile terminal, in particular a smartphone, having camera capabilities. Wherein, when the image capturing module 200 is a fixed focus module, the image capturing module 200 can be used as a front camera module of the smart phone; when the image capturing module 200 has a focusing function, the image capturing module 200 can also be used as a rear camera module of the smart phone. By using the image capturing module 200 with the optical system, the electronic device can obtain high quality images in dark environments such as night scenes and starry sky.

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

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

Claims

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

a second lens element with refractive power;

a third lens element with refractive power;

a fourth lens element with refractive power;

a fifth lens element with refractive power;

a sixth lens element with refractive power;

an eighth lens element with negative refractive power;

the optical system satisfies the following relationship:

1＜TTL/L＜2.5；

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

f14＞0；

f58＜0；

wherein f14 is a combined focal length of the first, second, third, and fourth lenses, and f58 is a combined focal length of the fifth, sixth, seventh, and eighth lenses.

3. The optical system according to claim 2, wherein the following relationship is satisfied:

-0.7＜f14/f58＜-0.1。

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

0.2＜Fno/TTL＜0.35；

wherein, Fno is the f-number of the optical system, TTL is the distance from the object-side surface of the first lens element to the imaging surface of the optical system on the optical axis, and the unit of TTL is mm.

5. The optical system according to claim 4, wherein the following relationship is satisfied:

Fno＜2.0。

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

TTL/Imgh＜1.5；

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

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

1.0＜TTL/|f|＜1.5；

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 f is an effective focal length of the optical system.

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

f/f1≤1.2；

wherein f is the effective focal length of the optical system, and f1 is the effective focal length of the first lens.

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

-0.10＜(R9+R10)/(R9*R10)＜0.25；

wherein R9 is a radius of curvature of an object-side surface of the fourth lens at an optical axis, R10 is a radius of curvature of an image-side surface of the fourth lens at the optical axis, and R9 and R10 are both in mm.

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

0.5＜(R3+R4)/f1＜3.5；

wherein R3 is a radius of curvature of an object-side surface of the first lens at an optical axis, R4 is a radius of curvature of an image-side surface of the first lens at the optical axis, and f1 is an effective focal length of the first lens.

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

0.8＜R5/R6＜3.5；

wherein R5 is a curvature radius of an object side surface of the second lens at an optical axis, and R6 is a curvature radius of an image side surface of the second lens at the optical axis.

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

8＜|R7+R8|/|R7-R8|＜48；

wherein R7 is a radius of curvature of an object-side surface of the third lens at an optical axis, and R8 is a radius of curvature of an image-side surface of the third lens at the optical axis.

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

-0.6＜f1/f2＜0.1；

wherein f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens.

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

1.8＜(R17*R18)/(R17-R18)＜3；

wherein R17 is a radius of curvature of an object-side surface of the eighth lens element at an optical axis, R18 is a radius of curvature of an image-side surface of the eighth lens element at the optical axis, and R17 and R18 are both in mm.

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

0.5＜ΣCT/f＜0.8；

wherein Σ CT is a sum of central thicknesses of the lenses in the optical system, and f is an effective focal length of the optical system.

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

0.40＜ΣCT/TTL＜0.62；

the sigma-delta CT is the sum of the central thicknesses of the lenses in the optical system, and the TTL is the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis.

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

0.20＜ET1/CT1＜0.60；

wherein ET1 is the edge thickness of the first lens and CT1 is the center thickness of the first lens.

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

0.80＜ET8/CT8＜3.00；

wherein ET8 is an edge thickness of the eighth lens and CT8 is a center thickness of the eighth lens.

19. An image capturing module, comprising a photosensitive element and the optical system of any one of claims 1 to 18, wherein the photosensitive element is disposed on an image side of the optical system.

20. An electronic device, comprising the image capturing module of claim 19.