CN111856716A

CN111856716A - Optical system, camera module, electronic equipment and automobile

Info

Publication number: CN111856716A
Application number: CN202010812494.9A
Authority: CN
Inventors: 蔡雄宇; 兰宾利; 周芮
Original assignee: Tianjin OFilm Opto Electronics Co Ltd
Current assignee: Tianjin OFilm Opto Electronics Co Ltd
Priority date: 2020-08-13
Filing date: 2020-08-13
Publication date: 2020-10-30

Abstract

The invention relates to an optical system, a camera module, electronic equipment and an automobile. The optical system includes in order from an object side to an image side: a first lens element with negative refractive power having a convex object-side surface and a concave image-side surface; the second lens element with negative refractive power has a concave object-side surface and a concave image-side surface at paraxial regions; a third lens element with positive refractive power having a convex object-side surface and a concave image-side surface; a fourth lens element with positive refractive power; a fifth lens element with negative refractive power cemented with the fourth lens element; and a sixth lens element with positive refractive power. The optical system satisfies: f1/(Rs2-SAGs2) is not less than 7 and not more than-4; f1 is the focal length of the first lens, Rs2 is the radius of curvature of the image-side surface of the first lens at the optical axis, and SAGs2 is the rise of the image-side surface of the first lens at the maximum effective aperture. Satisfying the above design can improve the imaging definition.

Description

Optical system, camera module, electronic equipment and automobile

Technical Field

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

Background

Since the camera lens is applied to electronic devices such as smart phones and tablet computers, the shooting performance of the device also changes with the increase of high-quality shooting requirements of users. Particularly, for automobiles, when the camera lens is applied to automobiles to monitor road information around the automobiles, the quality of the camera image directly affects the safety factor of drivers in lane changing, backing up and even automatic driving by using the camera image. For a general camera lens, under the condition that the intensity of incident light is large, a ghost phenomenon easily occurs on an imaging picture, so that the definition of the camera picture is reduced, and a system cannot obtain a clear imaging picture.

Disclosure of Invention

In view of the above, it is desirable to provide an optical system, a camera module, an electronic device and an automobile for improving the sharpness of an image.

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

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

the second lens element with negative refractive power has a concave object-side surface and a concave image-side surface at paraxial regions;

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

a fourth lens element with positive refractive power;

a fifth lens element with negative refractive power cemented with the fourth lens element; and

a sixth lens element with positive refractive power;

and the optical system satisfies the relationship:

-7≤f1/(Rs2-SAGs2)≤-4；

f1 is the focal length of the first lens, Rs2 is the radius of curvature of the image-side surface of the first lens at the optical axis, and SAGs2 is the sagittal height of the image-side surface of the first lens at the maximum effective aperture.

The first lens element with negative refractive power has a convex object-side surface at the paraxial region and a concave image-side surface at the paraxial region, so that the field angle of the system can be effectively enlarged, and the optical system can collect light rays incident from a large angle.

The second lens element with negative refractive power has a concave object-side surface and a concave image-side surface at paraxial positions, so that light from the first lens element can be adjusted, the light can be incident on the image side lens group at a small angle, and the improvement of imaging illumination is facilitated.

The third lens element with positive refractive power can converge the light rays from the first lens element and the second lens element, so that the divergent light rays can be constrained and completely enter the image space system. Since the first lens element and the second lens element are both negative lens elements, the third lens element with positive refractive power can balance the spherical aberration and the positional aberration generated by the first lens element and the second lens element.

The fourth lens and the fifth lens form a cemented lens, which can effectively reduce chromatic aberration of the system and reduce tolerance sensitivity of the system. In addition, the fourth lens element with positive refractive power and the fifth lens element with negative refractive power are advantageous for converging incident light rays further and then transferring the converged incident light rays to a rear optical system, so that the aperture of the image end of the system can be reduced.

The sixth lens element with positive refractive power can effectively converge light rays, so that the light rays diffused by the fifth lens element can be incident on an imaging surface of the system at a smaller incident angle, thereby being beneficial to improving the photosensitive performance of the photosensitive element.

In addition, when the relation condition is met, the image side surface of the first lens can be prevented from being excessively bent, so that the serious ghost phenomenon caused by mutual reflection of incident light on the image side surface of the first lens and the surfaces of all lenses on the image side is avoided, and the definition of an imaging picture is improved; in addition, the negative refractive power of the first lens element can be controlled within a reasonable range, so that large-angle light rays can be favorably emitted into the optical system, the field angle range of the optical system is further expanded, and the ultra-wide-angle design is realized. When the optical power exceeds the upper limit of the relational expression, the focal length of the first lens is too small, and the refractive power of the first lens is too strong, so that image formation of an image plane becomes too sensitive due to the change of the first lens, and larger aberration is easily generated; when the value is lower than the lower limit of the relational expression, the image-side surface of the first lens element is too curved to facilitate processing and manufacturing, and incident light is easily reflected between the image-side surface of the first lens element and each lens element on the image side to generate ghost images, so that the imaging quality of the optical system is reduced, and in addition, the refractive power of the first lens element is insufficient to facilitate light with large angle to enter the optical system, thereby facilitating the wide-angle and miniaturization design of the system.

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

3mm≤f1*f2/f3≤4.5mm；

f1 is the focal length of the first lens, f2 is the focal length of the second lens, and f3 is the focal length of the third lens. When the above relationship is satisfied, the refractive powers of the first lens element, the second lens element and the third lens element can be reasonably distributed, so that the refractive power of the lens assembly formed by the first lens element to the third lens element is controlled within a reasonable range and is not too strong, thereby preventing the aberration of the system from being corrected excessively, effectively reducing the aberration of the whole system, and being beneficial to reducing the tolerance sensitivity of the first lens element to the third lens element. In addition, when the above relationship is satisfied, it is also possible to prevent the lens assembly from having too weak refractive power to correct the system aberration well. When the upper limit of the relational expression is exceeded, the overall refractive power of the first lens element and the second lens element is insufficient, and large-angle light rays are difficult to enter the optical system, so that a sufficient object space view field range cannot be obtained, and the wide-angle design of the optical system is not facilitated. When the refractive power of the third lens element is lower than the lower limit of the relational expression, the refractive power of the third lens element is insufficient, which is not favorable for correcting aberration generated by the refraction of the large-angle incident light rays by the first lens element and the second lens element, thereby reducing the imaging quality.

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

-5≤f2/CT2≤-1；

f2 is the focal length of the second lens, and CT2 is the thickness of the second lens on the optical axis. When the refractive power meets the relationship, the refractive power and the center thickness of the second lens element can be reasonably configured, which is beneficial to correcting aberration generated by refraction of incident light rays through the first lens element, thereby improving the imaging quality of the optical system; if the range of the relational expression is exceeded, it is not favorable for correcting the aberration of the optical system, and it is difficult to obtain an image quality.

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

1.3≤f3/CT3≤2.1；

f3 is the focal length of the third lens, and CT3 is the thickness of the third lens on the optical axis. When the relationship is satisfied, the refractive power and the center thickness of the third lens element can be reasonably configured, so that the tolerance sensitivity of the center thickness of the third lens element can be reduced, the processing difficulty of the lens element can be reduced, the assembly yield of the system can be improved, and the production cost can be further reduced. When the central thickness of the third lens exceeds the upper limit of the relational expression, the central thickness of the third lens is too thin, and the system is too sensitive to the central thickness of the third lens, so that the processing of the lens is difficult to meet the required tolerance requirement, the assembly yield of the system is reduced, and the reduction of the production cost is not facilitated; when the thickness of the third lens is less than the lower limit of the relational expression, the central thickness of the third lens is too large, which is not favorable for shortening the length of the optical system.

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

5≤f45/f≤14；

f45 is the combined focal length of the fourth lens and the fifth lens, and f is the effective focal length of the optical system. When the above relationship is satisfied, the whole lens group composed of the fourth lens element and the fifth lens element has positive refractive power, so that aberration can be corrected for the system. And through the gluing design, the accumulated tolerance of the two elements (the fourth lens and the fifth lens) can be set to be the tolerance of an integrated element, so that the eccentricity sensitivity can be effectively reduced, the assembly sensitivity of a system is reduced, the problems of lens process manufacturing and lens assembly are solved, and the yield is improved. On the other hand, the aberration between the fourth lens and the fifth lens which form the cemented lens group can be mutually corrected, which is beneficial to improving the imaging resolution of the optical system. When the range of the relational expression is exceeded, the aberration of the optical system is disadvantageously corrected, thereby degrading the imaging quality.

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

|CT4-CT5|*|α4-α5|≤20mm·10^-6/K；

CT4 is the thickness of the fourth lens element on the optical axis, CT5 is the thickness of the fifth lens element on the optical axis, α 4 is the thermal expansion coefficient of the fourth lens element, and α 5 is the thermal expansion coefficient of the fifth lens element. When the relation is met, the central thickness and the thermal expansion coefficient of the fourth lens and the fifth lens can be well controlled, and the problem that the glued joint is cracked due to different deformation quantities under the effects of expansion with heat and contraction with cold can be effectively avoided, so that the optical system can still have stable and good imaging quality under a high-temperature or low-temperature environment.

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

0.5≤f6/CT6≤1.5；

f6 is the focal length of the sixth lens, and CT6 is the thickness of the sixth lens on the optical axis. When the above relation is satisfied, the refractive power and the center thickness of the third lens element can be reasonably configured, so that the emergent angle of the light ray emitted from the sixth lens element can be favorably reduced, the incident angle of the light ray emitted into the photosensitive element can be favorably reduced, and the photosensitive performance of the photosensitive element can be improved. When the upper limit of the relational expression is exceeded, the focal length of the sixth lens element is too long, the refractive power of the sixth lens element is insufficient, and the incident angle of light rays entering the photosensitive element is large, so that the photosensitive element cannot well acquire incident information, and the phenomenon of imaging distortion is caused; when the thickness of the center of the third lens is lower than the lower limit of the relational expression, the central thickness of the third lens is too large, the phenomenon of expansion with heat and contraction with cold of the lens becomes too obvious, and the thermal stability of the optical system is reduced.

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

7≤Imgh/EPD≤10；

imgh is the length of the effective imaging area on the imaging surface of the optical system in the horizontal direction, and EPD is the entrance pupil diameter of the optical system. When the relation is satisfied, the image plane size and the entrance pupil diameter of the optical system can be reasonably configured, so that the optical system has large image plane characteristics, the super-wide angle design of the system is facilitated, and meanwhile, the optical system with the large image plane and the super-wide angle characteristics has sufficient image plane brightness in the edge view field, so that the system has excellent imaging quality. When the upper limit of the relation is exceeded, the diameter of the entrance pupil of the system is too small, which is not beneficial to the design of a large aperture of the optical system and is not beneficial to improving the image surface brightness of the optical system; when the diameter of the entrance pupil of the optical system is smaller than the lower limit of the relational expression, the diameter of the entrance pupil is too large, so that astigmatism of marginal field rays can be increased, the image plane is curved, and the improvement of the imaging quality of the optical system is not facilitated.

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

6≤ΣCT/f≤10；

the sigma-delta CT is the sum of the thicknesses of all lenses in the optical system on the optical axis, and f is the effective focal length of the optical system. When the above relation is satisfied, the thickness and the focal length of the lens of the optical system can be well configured, which is beneficial to making the structure of the optical system compact, shortening the total length of the system, and the optical system can further realize the miniaturization design while satisfying the wide-angle design. When the focal length is lower than the lower limit of the relational expression, the focal length of the optical system is too long, which is not beneficial to the ultra-wide angle design of the system; when the upper limit of the relational expression is exceeded, the thickness distribution of each lens of the optical system is excessive, and the tolerance distribution of each lens is not facilitated, so that the eccentric sensitivity of the lens assembly process is improved, and the production yield is not facilitated to be improved.

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

-8mm≤f*tan(FOV/2)≤-5mm；

f is the effective focal length of the optical system, and the FOV is the maximum angle of view of the optical system in the horizontal direction of the effective imaging area on the imaging surface. When satisfying above-mentioned relation, optical system's angle of vision can be effectively promoted to realize super wide angle design, still be favorable to reducing the angle that light penetrated into photosensitive element simultaneously, improve photosensitive element's sensitization performance. When the relation is exceeded, the field angle of the system is insufficient, and enough object space information cannot be obtained; when the value is lower than the lower limit of the relational expression, a larger image plane deformation phenomenon is generated, which is not beneficial to the improvement of the imaging quality.

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

0≤|Nd5-Nd4|*100≤15；

nd4 is a d-line refractive index of the fourth lens, and Nd5 is a d-line refractive index of the fifth lens. When the upper limit condition of the relation is met, the d-line refractive indexes of the fourth lens and the fifth lens can be reasonably configured, so that the system aberration can be optimized, and the imaging analysis capability of the system can be improved. When the refractive index of the fourth lens element is larger than the refractive index of the fifth lens element, the aberration of the optical system is not corrected, so that the imaging quality of the system is reduced, and the d-line refractive index difference between the fourth lens element and the fifth lens element is too large, so that the risk that light rays are reflected between the adhesive surface between the fourth lens element and the fifth lens element and the surface of other lens elements to generate ghost images is increased.

In one embodiment, both the object-side surface and the image-side surface of the fourth lens element are convex, and both the object-side surface and the image-side surface of the fifth lens element are concave at the paraxial region.

An image capturing module includes a photosensitive element and the optical system of any of the above embodiments, wherein the photosensitive element is disposed on an image side of the optical system. By adopting the optical system, the camera module can also well inhibit the generation of high-order aberration, thereby having good imaging quality.

An electronic device comprises a fixing piece and the camera module, wherein the camera module is arranged on the fixing piece. Through adopting above-mentioned module of making a video recording, electronic equipment can possess good formation of image quality.

An automobile comprises an installation part and the electronic equipment, wherein the electronic equipment is arranged on the installation part. By adopting the electronic equipment, the influence of high-order aberration on the imaging picture obtained by the automobile can be effectively reduced, so that the high-quality imaging picture can still be obtained when the automobile runs, and the driving safety is further improved.

Drawings

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

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

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

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

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

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

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

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

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

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

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

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

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

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

fig. 15 is a schematic view of an automobile according to an embodiment of the present application.

Detailed Description

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

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

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

Referring to fig. 1, some embodiments of the present application provide an optical system 10, where the optical system 10 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, and a sixth lens L6, where the fourth lens L4 and the fifth lens L5 constitute a cemented lens. The first lens element L1 with negative refractive power, the second lens element L2 with negative refractive power, the third lens element L3 with positive refractive power, the fourth lens element L4 with positive refractive power, the fifth lens element L5 with negative refractive power and the sixth lens element L6 with positive refractive power. The lenses in the optical system 10 are coaxially arranged, that is, the optical axes of the lenses are all in the same straight line, which may be referred to as the optical axis of the optical system 10.

In some embodiments, the optical system 10 further includes a stop STO, which may be disposed between any two lenses or disposed on the object side of the first lens L1 or the image side of the second lens L2, and the center of the stop STO is located on the optical axis of the optical system 10. The lenses and stop STO of the optical system 10 may be mounted to the lens barrel. In other embodiments, the object side or image side of at least one lens in the optical system 10 can be coated with an opaque coating that leaves a light-transmitting area on the coated surface of the lens to allow incident light to pass through, while the area where the opaque material is located can block light from passing through, thereby allowing the opaque coating to act as a stop.

The first lens L1 includes an object side surface S1 and an image side surface S2, the second lens L2 includes an object side surface S3 and an image side surface S4, the third lens L3 includes an object side surface S5 and an image side surface S6, the fourth lens L4 includes an object side surface S7 and an image side surface S8, the fifth lens L5 includes an object side surface S9 and an image side surface S10, and the sixth lens L6 includes an object side surface S11 and an image side surface S12. In addition, the optical system 10 further has a virtual image plane S13, and the image plane S13 is located on the image side of the sixth lens element L6. Generally, the image forming surface S13 of the optical system 10 coincides with the photosensitive surface of the photosensitive element, which can be regarded as the image forming surface S13 of the optical system 10 for ease of understanding.

In the above embodiment, the object-side surface S1 of the first lens element L1 is convex and the image-side surface S2 is concave; the object-side surface S3 and the image-side surface S4 of the second lens L2 are both concave at the paraxial region; the object-side surface S5 of the third lens element L3 is convex paraxially, and the image-side surface S6 is concave paraxially. The surface shapes of the object side surface and the image side surface of the lens at the paraxial region are the surface shapes of the corresponding surfaces in the region near the optical axis.

The first lens element L1 with negative refractive power has a convex object-side surface S1 and a concave image-side surface S2, respectively, in a paraxial region of the first lens element L1, so that the field of view of the system can be effectively enlarged and the optical system 10 can collect light rays incident from a large angle.

The second lens element L2 has negative refractive power, and the object-side surface S3 and the image-side surface S4 of the second lens element L2 are both concave at the paraxial region, so that the light from the first lens element L1 can be adjusted to be incident on the image side lens group (the lens group consisting of the third lens element L3 and the sixth lens element L6) at a small angle, thereby facilitating the improvement of the imaging illumination.

The third lens element L3 with positive refractive power can converge the light beams from the first lens element L1 and the second lens element L2, so that the divergent light beams can be confined and enter the image space system completely. Since the first lens element L1 and the second lens element L2 are both negative lenses, the third lens element L3 with positive refractive power can balance the spherical aberration and the positional chromatic aberration generated by the first lens element L1 and the second lens element L2.

The fourth lens L4 and the fifth lens L5 constitute a cemented lens, which can effectively reduce chromatic aberration of the system and can reduce tolerance sensitivity of the system. In addition, since the fourth lens element L4 has positive refractive power and the fifth lens element L5 has negative refractive power, the arrangement is favorable for converging incident light further and then transferring the incident light to a rear optical system, so that the aperture of the image end of the system can be reduced.

The sixth lens element L6 has positive refractive power, so the sixth lens element L6 can effectively converge light beams, and the light beams diverged by the fifth lens element L5 can be incident on the image plane of the system at a smaller incident angle, thereby facilitating the improvement of the photosensitive performance of the photosensitive element.

In addition, in the embodiment of the present application, the optical system 10 satisfies the relationship:

f1/(Rs2-SAGs2) is not less than 7 and not more than-4; f1 is the focal length of the first lens L1, Rs2 is the radius of curvature of the image-side surface S2 of the first lens L1 at the optical axis, and SAGs2 is the rise of the image-side surface S2 of the first lens L1 at the maximum effective aperture. The rise is the distance from the center of the image side surface S2 of the first lens L1 to the maximum effective clear aperture of the surface in the direction parallel to the optical axis; when the value is a positive value, the maximum effective clear aperture of the surface is closer to the image side of the system than the center of the surface in a direction parallel to the optical axis of the system; when the value is negative, the plane has a larger effective clear aperture at the object side than at the center of the plane in a direction parallel to the optical axis of the system. Specifically, f1/(Rs2-SAGs2) in some embodiments may be-6.1, -6, -5.9, -5.8, -5.7, or-5.6. When the above relationship is satisfied, the image side surface S2 of the first lens L1 is prevented from being excessively curved, so that the incident light is prevented from being reflected mutually on the image side surface S2 of the first lens L1 and the surfaces of the lenses of the image side to generate a serious ghost phenomenon, and the definition of an imaging picture is improved; in addition, the negative refractive power of the first lens element L1 can be controlled within a reasonable range, which is favorable for the light with large angle to enter the optical system 10, and further expands the field angle range of the optical system 10, thereby realizing the super-wide design. When the upper limit of the relation is exceeded, the focal length of the first lens element L1 is too small, and the refractive power of the lens element is too strong, so that the image plane becomes too sensitive due to the change of the first lens element L1, and thus large aberration is easily generated; when the value is lower than the lower limit of the relationship, the image-side surface S2 of the first lens element L1 is too curved to facilitate manufacturing, and incident light is easily reflected between the image-side surface S2 of the first lens element L1 and each lens element on the image side to generate ghost, so that the imaging quality of the optical system 10 is reduced, and the refractive power of the first lens element L1 is insufficient to facilitate light with a large angle entering the optical system 10, thereby facilitating the design of wide angle and miniaturization of the system.

In some embodiments, the object-side surface S7 of the fourth lens element L4 is convex paraxially, and the image-side surface S8 is convex paraxially. The object-side surface S9 of the fifth lens element L5 is concave at the paraxial region, and the image-side surface S10 is concave at the paraxial region.

In some embodiments, the object-side surface and/or the image-side surface of at least one lens in the optical system 10 is aspheric, so that the object-side surface and/or the image-side surface of the lens can be designed more flexibly, the lens can well solve the problems of poor imaging, distortion of the view field, narrow field of view and the like under the condition of small and thin lens, the system can have good imaging quality without arranging too many lenses, and the length of the optical system 10 can be shortened. In some embodiments, the object-side surface and/or the image-side surface of at least one lens in the optical system 10 is spherical, and the spherical lens has a simple manufacturing process and a low production cost. Specifically, in some embodiments, the object-side surface and the image-side surface of the first lens L1 and the third lens L3 are both spherical, and the object-side surface and the image-side surface of the second lens L2, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are all aspherical. In some embodiments, the specific arrangement of the spherical surface and the aspherical surface between the lenses depends on the actual design requirement, and is not described herein. The aberration of the system can be effectively eliminated by the cooperation of the spherical surface and the aspherical surface, so that the optical system 10 has good imaging quality, and simultaneously, the flexibility of lens design and assembly is improved, and the system is balanced between high imaging quality and low cost. It is to be noted that the specific shapes of the spherical and aspherical surfaces in the embodiments are not limited to those shown in the drawings, which are mainly for exemplary reference and are not drawn strictly to scale.

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

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

In some embodiments, each lens in the optical system 10 is made of plastic. In other embodiments, each lens of the optical system 10 is made of glass. The plastic lens can reduce the weight of the optical system 10 and the manufacturing cost, while the glass lens can withstand higher temperatures and has excellent optical effects. In other embodiments, the first lens L1 and the fourth lens L4 are made of glass, and the other lenses in the optical system 10 are made of plastic, so that the lenses located at the object side in the optical system 10 are made of glass, and therefore, the glass lenses located at the object side have a good tolerance effect on extreme environments, are not susceptible to aging and the like caused by the influence of the object side environment, and therefore, when the optical system 10 is in the extreme environments such as exposure to high temperature, the optical performance and cost of the system can be well balanced by using such a structure. Of course, the configuration relationship of the lens materials in the optical system 10 is not limited to the above embodiments, any one of the lenses may be made of plastic or glass, and the specific configuration relationship is determined according to the actual design requirement, which is not described herein again.

In some embodiments, the optical system 10 includes a filter 110, and the filter 110 is disposed on the image side of the sixth lens L6 and is fixed relative to each lens in the optical system 10. The filter 110 is an infrared cut filter for filtering infrared light, and prevents the infrared light from reaching the imaging surface S13 of the system, so as to prevent the infrared light from interfering with normal imaging. The filter 110 may be assembled with each lens as part of the optical system 10. For example, in some embodiments, each lens in the optical system 10 is mounted within a lens barrel, and the filter 110 is mounted at the image end of the lens barrel. In other embodiments, the filter 110 is not a component of the optical system 10, and the filter 110 can be installed between the optical system 10 and the photosensitive element when the optical system 10 and the photosensitive element are assembled into a camera module. In some embodiments, the optical filter 110 may also be disposed on the object side of the first lens L1. In addition, in some embodiments, the filter 110 may not be provided, and an infrared filter is provided on an object-side surface or an image-side surface of at least one of the first lens L1 through the sixth lens L6 to filter infrared light.

In some embodiments, the optical system 10 further satisfies at least one of the following relationships:

f1 x f2/f3 is not less than 3mm and not more than 4.5 mm; f1 is the focal length of the first lens L1, f2 is the focal length of the second lens L2, and f3 is the focal length of the third lens L3. In particular, f1 × f2/f3 in some embodiments may be 3.55mm, 3.58mm, 3.6mm, 3.65mm, 3.68mm, 3.7mm, or 3.72 mm. When the above relationship is satisfied, the refractive powers of the first lens element L1, the second lens element L2 and the third lens element L3 can be reasonably distributed, so that the refractive powers of the lens assembly formed by the first lens element L1 to the third lens element L3 can be controlled within a reasonable range without being too strong, thereby preventing the aberration of the system from being excessively corrected, effectively reducing the aberration of the whole system, and being beneficial to reducing the tolerance sensitivity of the first lens element L1 to the third lens element L3. In addition, when the above relationship is satisfied, it is also possible to prevent the lens assembly from having too weak refractive power to correct the system aberration well. When the upper limit of the relationship is exceeded, the total refractive power of the first lens element L1 and the second lens element L2 is insufficient, and large-angle light rays are difficult to enter the optical system 10, so that a sufficient object field range cannot be obtained, which is not favorable for the wide-angle design of the optical system 10. If the refractive power of the third lens element L3 is insufficient below the lower limit of the relationship, it is not favorable for correcting the aberration generated by the refraction of the incident light beams with large angles by the first lens element L1 and the second lens element L2, thereby reducing the image quality.

F2/CT2 is more than or equal to-5 and less than or equal to-1; f2 is the focal length of the second lens L2, and CT2 is the thickness of the second lens L2 on the optical axis. Specifically, f2/CT2 in some embodiments can be-4.2, -4.1, -4, -3.7, -3.5, -3.2, -3, or-2.9. When the refractive power satisfies the above relationship, the refractive power and the center thickness of the second lens element L2 can be reasonably configured, which is favorable for correcting the aberration generated by the incident light refracted by the first lens element L1, thereby improving the imaging quality of the optical system 10. If the range exceeds the relational expression range, it is not favorable to correct the aberration of the optical system 10, and it is difficult to obtain an image quality.

F3/CT3 is more than or equal to 1.3 and less than or equal to 2.1; f3 is the focal length of the third lens L3, and CT3 is the thickness of the third lens L3 on the optical axis. Specifically, f3/CT3 in some embodiments can be 1.5, 1.55, 1.6, 1.8, 1.9, 1.95, or 2. When the above relationship is satisfied, the refractive power and the center thickness of the third lens element L3 can be reasonably configured, so that the tolerance sensitivity of the center thickness of the third lens element L3 can be reduced, the difficulty of the lens processing process can be reduced, the assembly yield of the system can be improved, and the production cost can be further reduced. When the central thickness of the third lens L3 is too thin, the system is too sensitive to the central thickness of the third lens L3, so that the required tolerance requirement is difficult to meet in the lens processing, the assembly yield of the system is reduced, and the production cost is not reduced; below the lower limit of the relational expression, the center thickness of the third lens L3 is too large, which is disadvantageous for shortening the length of the optical system 10.

F45/f is more than or equal to 5 and less than or equal to 14; f45 is the combined focal length of the fourth lens L4 and the fifth lens L5, and f is the effective focal length of the optical system 10. Specifically, f45/f in some embodiments may be 6.8, 7, 7.2, 7.6, 8, 8.5, 9, 10, 10.5, 11, 11.5, or 12. When the above relationship is satisfied, the entire lens assembly composed of the fourth lens element L4 and the fifth lens element L5 has positive refractive power, so that aberration can be corrected for the system. And through the gluing design, the accumulated tolerance of the two elements (the fourth lens L4 and the fifth lens L5) can be set to be the tolerance of an integrated element, so that the eccentricity sensitivity can be effectively reduced, the assembly sensitivity of the system is reduced, the problems of lens process manufacturing and lens assembly are solved, and the yield is improved. On the other hand, aberrations between the fourth lens L4 and the fifth lens L5 constituting the cemented lens group can be mutually corrected, which is advantageous for improving the imaging resolution of the optical system 10. If the relationship is exceeded, the aberration of the optical system 10 is not corrected, and the imaging quality is degraded.

|CT4-CT5|*|α4-α5|≤20mm·10^-6K; CT4 is the thickness of the fourth lens L4 on the optical axis, CT5 is the thickness of the fifth lens L5 on the optical axis, α 4 is the thermal expansion coefficient of the fourth lens L4, and α 5 is the thermal expansion coefficient of the fifth lens L5. In particular, | CT4-CT5| α 4- α 5| in some embodiments may be 6.2, 6.5, 6.8, 7, 7.5, 8, 9, 11, 11.5, 12, 12.5, or 13. When the above relationship is satisfied, the central thicknesses and thermal expansion coefficients of the fourth lens L4 and the fifth lens L5 can be well controlled, and the problem that the cemented part is cracked due to different deformation amounts under the effect of thermal expansion and cold contraction of the fourth lens L4 and the fifth lens L5 can be effectively avoided, so that the optical system 10 can still have stable and good imaging quality under a high-temperature or low-temperature environment.

F6/CT6 is more than or equal to 0.5 and less than or equal to 1.5; f6 is the focal length of the sixth lens element L6, and CT6 is the thickness of the sixth lens element L6 on the optical axis. Specifically, f6/CT6 in some embodiments can be 0.95, 1, 1.15, 1.2, 1.25, or 1.3. When the above relationship is satisfied, the refractive power and the center thickness of the third lens element L3 can be reasonably configured, so as to facilitate reducing the exit angle of the light exiting from the sixth lens element L6, and thus facilitate reducing the incident angle of the light entering the photosensitive element, thereby improving the photosensitive performance of the photosensitive element. When the upper limit of the relationship is exceeded, the focal length of the sixth lens element L6 is too long, and the refractive power of the lens element is insufficient, so that the incident angle of light entering the photosensitive element is large, and the photosensitive element cannot acquire incident information well, thereby causing the phenomenon of imaging distortion; below the lower limit of the relationship, the central thickness of the third lens L3 is too large, and the thermal expansion and contraction of the lens become too significant, resulting in a decrease in the thermal stability of the optical system 10.

Imgh/EPD is more than or equal to 7 and less than or equal to 10; imgh is the length of the effective imaging area in the horizontal direction on the imaging plane S13 of the optical system 10, and EPD is the entrance pupil diameter of the optical system 10. Specifically, the Imgh/EPD in some embodiments may be 8.85, 8.9, 9, 9.15, 9.2, 9.25, 9.3, 9.5, 9.55, or 9.6. In general, the effective imaging area of the imaging surface S13 of the optical system 10 coincides with the rectangular photosensitive surface of the photosensitive element, and the horizontal direction of the effective imaging area can be understood as the longitudinal direction of the rectangular photosensitive surface. When the above relationship is satisfied, the image plane size and the entrance pupil diameter of the optical system 10 can be reasonably configured, so that the optical system 10 has a large image plane characteristic, which is beneficial to the super-wide angle design of the system, and meanwhile, the optical system 10 having the large image plane and the super-wide angle characteristic can have sufficient image plane brightness in the peripheral field of view, so that the system has excellent imaging quality. When the upper limit of the relation is exceeded, the diameter of the entrance pupil of the system is too small, which is not beneficial to the design of a large aperture of the optical system 10 and is not beneficial to improving the image surface brightness of the optical system 10; when the diameter of the entrance pupil is smaller than the lower limit of the relational expression, the diameter of the entrance pupil is too large, so that astigmatism of marginal field rays is increased, the image plane is curved, and the improvement of the imaging quality of the optical system 10 is not facilitated.

6 is less than or equal to Sigma CT/f is less than or equal to 10; Σ CT is the sum of thicknesses of the lenses in the optical system 10 on the optical axis, and f is the effective focal length of the optical system 10. Specifically, Σ CT/f in some embodiments may be 7.6, 7.8, 8, 8.3, 8.6, 9, 9.1, or 9.2. When the above relationship is satisfied, the lens thickness and the focal length of the optical system 10 can be configured well, which is advantageous for making the structure of the optical system 10 compact, shortening the total length of the system, and further realizing the miniaturized design while the optical system 10 satisfies the wide-angle design. When the focal length is lower than the lower limit of the relational expression, the focal length of the optical system 10 is too long, which is not favorable for the ultra-wide angle design of the system; when the upper limit of the relationship is exceeded, the thickness distribution of each lens of the optical system 10 is too large, which is not favorable for the tolerance distribution of each lens, thereby increasing the eccentricity sensitivity of the lens assembly process and being not favorable for the improvement of the production yield.

-8mm ≤ f tan (FOV/2) ≤ 5 mm; f is the effective focal length of the optical system 10, and the FOV is the maximum angle of view of the optical system 10 in the horizontal direction of the effective imaging area on the imaging plane S13. In general, the effective image forming area of the image forming surface S13 of the optical system 10 coincides with the rectangular photosensitive surface of the photosensitive element, and the horizontal direction of the optical system 10 can be understood as the longitudinal direction of the rectangular photosensitive surface. In particular, f tan (FOV/2) in some embodiments may be-7.1, -7, -6.8, -6.5, -6.3, -6.2, -6.15, or-6.1. When the above relationship is satisfied, the field angle of the optical system 10 can be effectively increased to realize an ultra-wide-angle design, and simultaneously, the angle of the light entering the photosensitive element can be reduced, and the photosensitive performance of the photosensitive element can be improved. When the relation is exceeded, the field angle of the system is insufficient, and enough object space information cannot be obtained; when the value is lower than the lower limit of the relational expression, a larger image plane deformation phenomenon is generated, which is not beneficial to the improvement of the imaging quality.

The absolute Nd5-Nd4 absolute 100 is more than or equal to 0 and less than or equal to 15; nd4 is the d-line refractive index of fourth lens L4, Nd5 is the d-line refractive index of fifth lens L5, and Nd4 and Nd5 are both d-line refractive indices of the lenses under d light (587.56 nm). In particular, the | Nd5-Nd4| x 100 in some embodiments may be 4.3, 4.5, 4.8, 5, 6, 7, 9, 9.5, 9.8, 10, or 10.2. When the upper limit condition of the above relationship is satisfied, the d-line refractive indexes of the fourth lens L4 and the fifth lens L5 can be reasonably configured, so that the system aberration can be optimized, and the imaging analysis capability of the system can be improved. When the range of the relation is exceeded, it is not favorable to correct the aberration of the optical system 10, thereby reducing the imaging quality of the system, and in addition, the d-line refractive index difference between the fourth lens L4 and the fifth lens L5 is too large, increasing the risk that the light is reflected between the adhesive surface between the fourth lens L4 and the fifth lens L5 and other lens surfaces to generate ghost.

It should be noted that when any of the above relationships is satisfied, the optical system 10 can have the effect described by the corresponding relationship.

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

first embodiment

Referring to fig. 1, in the first embodiment, the optical system 10 includes, in order from an object side to an image side, a first lens element L1 with negative refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a stop STO, a fourth lens element L4 with positive refractive power, a fifth lens element L5 with negative refractive power, and a sixth lens element L6 with positive refractive power. Fig. 2 includes a longitudinal spherical aberration diagram, an astigmatism diagram, and a distortion diagram of the optical system 10 in the first embodiment. The reference wavelengths of the astigmatism diagrams and the distortion diagrams of the following examples (first to fifth examples) are both 546.07 nm.

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

The object-side surface S3 of the second lens element L2 is concave paraxially, and the image-side surface S4 is concave paraxially.

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

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

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

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

Wherein the image-side surface S8 of the fourth lens L4 is cemented with the object-side surface S9 of the fifth lens L5.

The second lens element L2 has negative refractive power, and the object-side surface S3 and the image-side surface S4 of the second lens element L2 are both concave at the paraxial region, so that the light from the first lens element L1 can be adjusted to be incident on the image lens group (the lens group consisting of the third lens element L3 and the sixth lens element L6) at a small angle, thereby facilitating the improvement of the imaging illumination.

The object-side and image-side surfaces of the first lens L1 and the third lens L3 are spherical, and the object-side and image-side surfaces of the second lens L2, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are aspherical. The aberration of the system can be effectively eliminated by the cooperation of the spherical surface and the aspherical surface, so that the optical system 10 has good imaging quality, and simultaneously, the flexibility of lens design and assembly is improved, and the system is balanced between high imaging quality and low cost. The first lens L1 and the third lens L3 are made of glass, and the second lens L2, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are made of plastic.

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

f1/(Rs2-SAGs2) ═ 6.01; f1 is the focal length of the first lens L1, Rs2 is the radius of curvature of the image-side surface S2 of the first lens L1 at the optical axis, and SAGs2 is the rise of the image-side surface S2 of the first lens L1 at the maximum effective aperture. The rise is the distance from the center of the image side surface S2 of the first lens L1 to the maximum effective clear aperture of the surface in the direction parallel to the optical axis; when the value is a positive value, the maximum effective clear aperture of the surface is closer to the image side of the system than the center of the surface in a direction parallel to the optical axis of the system; when the value is negative, the plane has a larger effective clear aperture at the object side than at the center of the plane in a direction parallel to the optical axis of the system. When the above relationship is satisfied, the image side surface S2 of the first lens L1 is prevented from being excessively curved, so that the incident light is prevented from being reflected mutually on the image side surface S2 of the first lens L1 and the surfaces of the lenses of the image side to generate a serious ghost phenomenon, and the definition of an imaging picture is improved; in addition, the negative refractive power of the first lens element L1 can be controlled within a reasonable range, which is favorable for the light with large angle to enter the optical system 10, and further expands the field angle range of the optical system 10, thereby realizing the super-wide design.

f1 × f2/f3 is 3.66 mm; f1 is the focal length of the first lens L1, f2 is the focal length of the second lens L2, and f3 is the focal length of the third lens L3. When the above relationship is satisfied, the refractive powers of the first lens element L1, the second lens element L2 and the third lens element L3 can be reasonably distributed, so that the refractive powers of the lens assembly formed by the first lens element L1 to the third lens element L3 can be controlled within a reasonable range without being too strong, thereby preventing the aberration of the system from being excessively corrected, effectively reducing the aberration of the whole system, and being beneficial to reducing the tolerance sensitivity of the first lens element L1 to the third lens element L3. In addition, when the above relationship is satisfied, it is also possible to prevent the lens assembly from having too weak refractive power to correct the system aberration well.

f2/CT2 is-4.15; f2 is the focal length of the second lens L2, and CT2 is the thickness of the second lens L2 on the optical axis. When the refractive power satisfies the above relationship, the refractive power and the center thickness of the second lens element L2 can be reasonably configured, which is favorable for correcting the aberration generated by the incident light refracted by the first lens element L1, thereby improving the imaging quality of the optical system 10.

f3/CT3 is 1.63; f3 is the focal length of the third lens L3, and CT3 is the thickness of the third lens L3 on the optical axis. When the above relationship is satisfied, the refractive power and the center thickness of the third lens element L3 can be reasonably configured, so that the tolerance sensitivity of the center thickness of the third lens element L3 can be reduced, the difficulty of the lens processing process can be reduced, the assembly yield of the system can be improved, and the production cost can be further reduced.

f45/f is 6.6; f45 is the combined focal length of the fourth lens L4 and the fifth lens L5, and f is the effective focal length of the optical system 10. When the above relationship is satisfied, the entire lens assembly composed of the fourth lens element L4 and the fifth lens element L5 has positive refractive power, so that aberration can be corrected for the system. And through the gluing design, the accumulated tolerance of the two elements (the fourth lens L4 and the fifth lens L5) can be set to be the tolerance of an integrated element, so that the eccentricity sensitivity can be effectively reduced, the assembly sensitivity of the system is reduced, the problems of lens process manufacturing and lens assembly are solved, and the yield is improved. On the other hand, aberrations between the fourth lens L4 and the fifth lens L5 constituting the cemented lens group can be mutually corrected, which is advantageous for improving the imaging resolution of the optical system 10.

|CT4-CT5|*|α4-α5|＝7.87mm·10^-6K; CT4 is the thickness of the fourth lens L4 on the optical axis, CT5 is the thickness of the fifth lens L5 on the optical axis, α 4 is the thermal expansion coefficient of the fourth lens L4, and α 5 is the thermal expansion coefficient of the fifth lens L5. When the above relationship is satisfied, the central thicknesses and thermal expansion coefficients of the fourth lens L4 and the fifth lens L5 can be well controlled, and the problem that the cemented part is cracked due to different deformation amounts under the effect of thermal expansion and cold contraction of the fourth lens L4 and the fifth lens L5 can be effectively avoided, so that the optical system 10 can still have stable and good imaging quality under a high-temperature or low-temperature environment.

f6/CT6 is 1.23; f6 is the focal length of the sixth lens element L6, and CT6 is the thickness of the sixth lens element L6 on the optical axis. When the above relationship is satisfied, the refractive power and the center thickness of the third lens element L3 can be reasonably configured, so as to facilitate reducing the exit angle of the light exiting from the sixth lens element L6, and thus facilitate reducing the incident angle of the light entering the photosensitive element, thereby improving the photosensitive performance of the photosensitive element.

Imgh/EPD is 9.11; imgh is the length of the effective imaging area in the horizontal direction on the imaging plane S13 of the optical system 10, and EPD is the entrance pupil diameter of the optical system 10. In general, the effective imaging area of the imaging surface S13 of the optical system 10 coincides with the rectangular photosensitive surface of the photosensitive element, and the horizontal direction of the effective imaging area can be understood as the longitudinal direction of the rectangular photosensitive surface. When the above relationship is satisfied, the image plane size and the entrance pupil diameter of the optical system 10 can be reasonably configured, so that the optical system 10 has a large image plane characteristic, which is beneficial to the super-wide angle design of the system, and meanwhile, the optical system 10 having the large image plane and the super-wide angle characteristic can have sufficient image plane brightness in the peripheral field of view, so that the system has excellent imaging quality.

Sigma CT/f is 7.59; Σ CT is the sum of thicknesses of the lenses in the optical system 10 on the optical axis, and f is the effective focal length of the optical system 10. When the above relationship is satisfied, the lens thickness and the focal length of the optical system 10 can be configured well, which is advantageous for making the structure of the optical system 10 compact, shortening the total length of the system, and further realizing the miniaturized design while the optical system 10 satisfies the wide-angle design.

f tan (FOV/2) ═ 7.15 mm; f is the effective focal length of the optical system 10, and the FOV is the maximum angle of view of the optical system 10 in the horizontal direction of the effective imaging area on the imaging plane S13. In general, the effective image forming area of the image forming surface S13 of the optical system 10 coincides with the rectangular photosensitive surface of the photosensitive element, and the horizontal direction of the optical system 10 can be understood as the longitudinal direction of the rectangular photosensitive surface. When the above relationship is satisfied, the field angle of the optical system 10 can be effectively increased to realize an ultra-wide-angle design, and simultaneously, the angle of the light entering the photosensitive element can be reduced, and the photosensitive performance of the photosensitive element can be improved.

L Nd5-Nd4 l 100 ═ 10.3; nd4 is the d-line (587.56nm) refractive index of the fourth lens L4, and Nd5 is the d-line (587.56nm) refractive index of the fifth lens L5. When the upper limit condition of the above relationship is satisfied, the d-line refractive indexes of the fourth lens L4 and the fifth lens L5 can be reasonably configured, so that the system aberration can be optimized, and the imaging analysis capability of the system can be improved.

In addition, each lens parameter of the optical system 10 in the first embodiment is given by table 1 and table 2. Table 2 shows the aspherical coefficients of the corresponding lens surfaces in table 1, where K is a conic coefficient and Ai is a coefficient corresponding to the i-th high-order term in the aspherical surface formula. The elements from the object side to the image side are arranged in the order of the elements from the top to the bottom in table 1, and the image plane (image forming plane S13) can be understood as the photosensitive surface of the photosensitive element at the later stage when the photosensitive element is assembled. The surface numbers 1 and 2 correspond to the object-side surface S1 and the image-side surface S2 of the first lens L1, respectively, that is, in the same lens, the surface with the smaller surface number is the object-side surface, and the surface with the larger surface number is the image-side surface. In particular, the surface number 8 represents the object-side surface S7 of the fourth lens L4. The Y radius in table 1 is the radius of curvature of the object-side surface or the image-side surface of the corresponding surface number at the optical axis. The first value of the "thickness" parameter set of the lens is the thickness of the lens on the optical axis, the second value is the distance from the image-side surface of the lens to the object-side surface of the next optical element on the optical axis, and when the next optical element of the lens is the stop, the second value represents the distance from the image-side surface of the lens to the center of the stop STO on the optical axis. The value of stop ST0 in the "thickness" parameter column is the distance on the optical axis from the center of stop STO to the object-side surface of the subsequent lens. The optical axes of the lenses in the embodiment of the present application are on the same straight line as the optical axis of the optical system 10. The reference wavelength of the refractive index, Abbe number and focal length in the following examples was 587.56 nm. In addition, the relational expression calculation and the lens structure of each example are based on data in parameter tables (table 1, table 2, table 3, table 4, and the like).

In the first embodiment, the effective focal length f of the optical system 10 is 1.26mm, the f-number FNO is 2.1, and the maximum horizontal viewing angle FOV of the effective imaging area of the optical system 10 on the imaging plane S13 is 200 °.

TABLE 1

TABLE 2

Number of noodles

3

4

8

9

10

11

12

K

-5.70E+00

-9.71E-01

4.02E+00

1.12E+00

-9.79E+01

-1.51E+00

-2.78E-01

A4

1.54E-04

-1.54E-03

-2.46E-02

-2.38E-01

-4.18E-02

-3.37E-02

1.82E-02

A6

-5.98E-06

3.47E-03

2.78E-02

7.31E-02

2.62E-02

9.31E-03

-4.70E-03

A8

0.00E+00

-7.53E-04

-5.22E-02

1.71E-02

-6.11E-03

-2.88E-03

1.32E-03

A10

0.00E+00

1.30E-04

3.79E-02

-7.42E-03

1.00E-03

5.92E-04

-2.12E-04

A12

0.00E+00

-9.45E-06

-1.23E-02

-6.09E-03

2.67E-05

-4.56E-05

0.00E+00

A14

0.00E+00

-3.31E-05

0.00E+00

A16

0.00E+00

A18

0.00E+00

A20

0.00E+00

Fig. 2 includes a Longitudinal Spherical Aberration diagram (Longitudinal Spherical Aberration) of optical system 10, which shows the convergent focus deviation of light rays of different wavelengths through the lens. The ordinate of the longitudinal spherical aberration diagram represents the Normalized Pupil coordinate (Normalized Pupil coordmator) from the Pupil center to the Pupil edge, and the abscissa represents the distance (in mm) of the imaging plane from the intersection point of the ray with the optical axis. It can be known from the longitudinal spherical aberration diagram that the convergent focus deviation degrees of the light rays with different wavelengths in the first embodiment tend to be consistent, and the diffuse speckle or the chromatic halo in the imaging picture is effectively suppressed.

FIG. 2 also includes a field curvature plot (ASTIGMATIC FIELD CURVES) of optical system 10, where the S-curve represents the arc-off-field curvature at 546.07nm and the T-curve represents the meridional field curvature at 546.07 nm. As can be seen from the figure, the field curvature of the system is small, and the center and the edge of the field of view have clear imaging.

In addition, fig. 2 also includes a DISTORTION map (distorsion) of the optical system 10, and it can be seen from the map that 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, in the second embodiment, the optical system 10 includes, in order from the object side to the image side, the first lens element L1 with negative refractive power, the second lens element L2 with negative refractive power, the third lens element L3 with positive refractive power, a stop STO, the fourth lens element L4 with positive refractive power, the fifth lens element L5 with negative refractive power, and the sixth lens element L6 with positive refractive power. Fig. 4 includes a longitudinal spherical aberration diagram, an astigmatism diagram, and a distortion diagram of the optical system 10 in the second embodiment.

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

TABLE 3

TABLE 4

The camera module 10 in this embodiment satisfies the following relationship:

f1*f2/f3	3.56	f6/CT6	1.32
				f1/(Rs2-SAGs2)	-6.10	Imgh/EPD	9.24
f2/CT2	-4.25	ΣCT/f	7.69
				f3/CT3	1.72	f*tan(FOV/2)	-6.98
f45/f	6.79	\|Nd5-Nd4\|*100	10.30
				\|CT4-CT5\|*\|α4-α5\|	8.23

as can be seen from the aberration diagram in fig. 4, the longitudinal spherical aberration, curvature of field, and distortion of the optical system 10 are well controlled, so that the optical system 10 has good imaging quality.

Third embodiment

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

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

TABLE 5

TABLE 6

Number of noodles

3

4

8

9

10

11

12

K

9.65E+01

-9.75E-01

4.95E+00

-1.42E+00

4.87E+01

-5.38E+00

-6.16E-01

A4

-7.02E-04

-4.30E-03

-1.40E-02

-1.65E-01

-4.38E-02

-2.38E-02

1.86E-02

A6

2.31E-05

4.44E-03

1.33E-02

-9.83E-02

2.32E-02

1.02E-02

-4.88E-03

A8

0.00E+00

-1.30E-03

-3.21E-02

1.72E-01

-6.31E-03

-3.47E-03

1.27E-03

A10

0.00E+00

2.28E-04

2.74E-02

-1.22E-01

1.25E-03

6.55E-04

-2.12E-04

A12

0.00E+00

-1.47E-05

-1.04E-02

2.31E-02

-5.81E-05

-4.45E-05

0.00E+00

A14

0.00E+00

A16

0.00E+00

A18

0.00E+00

A20

0.00E+00

The camera module 10 in this embodiment satisfies the following relationship:

f1*f2/f3	3.73	f6/CT6	1.13
				f1/(Rs2-SAGs2)	-5.99	Imgh/EPD	9.26
f2/CT2	-4.15	ΣCT/f	7.97
				f3/CT3	1.45	f*tan(FOV/2)	-7.03
f45/f	9.43	\|Nd5-Nd4\|*100	10.30
				\|CT4-CT5\|*\|α4-α5\|	6.02

as can be seen from the aberration diagram in fig. 6, the longitudinal spherical aberration, curvature of field, and distortion of the optical system 10 are well controlled, so that the optical system 10 has good imaging quality.

Fourth embodiment

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

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

TABLE 7

TABLE 8

Number of noodles

3

4

8

9

10

11

12

K

-9.90E+01

-1.02E+00

3.51E+00

-3.30E-01

4.69E+01

-6.28E+00

-6.98E-01

A4

-2.29E-04

-9.34E-03

-1.90E-02

-1.94E-01

-5.18E-02

-2.22E-02

2.18E-02

A6

1.14E-05

8.24E-03

1.69E-02

-1.14E-01

2.43E-02

9.87E-03

-5.50E-03

A8

0.00E+00

-2.69E-03

-3.91E-02

2.33E-01

-6.14E-03

-3.52E-03

1.38E-03

A10

0.00E+00

5.15E-04

3.11E-02

-1.65E-01

1.11E-03

6.56E-04

-2.37E-04

A12

0.00E+00

-3.78E-05

-1.08E-02

3.65E-02

-5.58E-05

-4.30E-05

0.00E+00

A14

0.00E+00

A16

0.00E+00

A18

0.00E+00

A20

0.00E+00

The camera module 10 in this embodiment satisfies the following relationship:

f1*f2/f3	3.54	f6/CT6	1.17
				f1/(Rs2-SAGs2)	-5.99	Imgh/EPD	9.41
f2/CT2	-4.12	ΣCT/f	7.99
				f3/CT3	1.66	f*tan(FOV/2)	-6.92
f45/f	7.12	\|Nd5-Nd4\|*100	10.30
				\|CT4-CT5\|*\|α4-α5\|	6.83

as can be seen from the aberration diagram in fig. 8, the longitudinal spherical aberration, curvature of field, and distortion of the optical system 10 are well controlled, so that the optical system 10 has good imaging quality.

Fifth embodiment

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

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

TABLE 9

Watch 10

The camera module 10 in this embodiment satisfies the following relationship:

f1*f2/f3	3.53	f6/CT6	0.92
				f1/(Rs2-SAGs2)	-5.55	Imgh/EPD	8.80
f2/CT2	-2.89	ΣCT/f	9.20
				f3/CT3	2.02	f*tan(FOV/2)	-6.07
f45/f	11.66	\|Nd5-Nd4\|*100	4.00
				\|CT4-CT5\|*\|α4-α5\|	13.31

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

Sixth embodiment

Referring to fig. 11, in the sixth embodiment, the optical system 10 includes, in order from the object side to the image side, the first lens element L1 with negative refractive power, the second lens element L2 with negative refractive power, the third lens element L3 with positive refractive power, a stop STO, the fourth lens element L4 with positive refractive power, the fifth lens element L5 with negative refractive power, and the sixth lens element L6 with positive refractive power. Fig. 12 includes a longitudinal spherical aberration diagram, an astigmatism diagram, and a distortion diagram of the optical system 10 in the sixth embodiment.

In addition, the lens parameters in the sixth embodiment are given in tables 11 and 12, wherein the definitions of the structures and parameters can be obtained from the first embodiment, which is not repeated herein.

TABLE 11

TABLE 12

Number of noodles

3

4

8

9

10

11

12

K

-9.90E+01

-1.11E+00

5.53E+00

-1.93E+00

-2.78E+01

-7.45E+00

-1.11E+00

A4

-3.55E-04

-1.08E-02

-1.93E-02

-1.71E-01

-5.93E-02

-1.73E-02

2.83E-02

A6

1.67E-05

1.06E-02

1.66E-02

-1.66E-01

2.41E-02

9.54E-03

-5.93E-03

A8

0.00E+00

-3.27E-03

-3.86E-02

2.63E-01

-6.37E-03

-3.59E-03

1.26E-03

A10

0.00E+00

5.67E-04

2.95E-02

-1.67E-01

1.08E-03

6.67E-04

-2.19E-04

A12

0.00E+00

-3.78E-05

-1.08E-02

3.65E-02

-5.58E-05

-4.30E-05

1.70E-05

A14

0.00E+00

A16

0.00E+00

A18

0.00E+00

A20

0.00E+00

The camera module 10 in this embodiment satisfies the following relationship:

f1*f2/f3	3.53	f6/CT6	0.91
				f1/(Rs2-SAGs2)	-5.87	Imgh/EPD	9.64
f2/CT2	-3.11	ΣCT/f	9.13
				f3/CT3	2.06	f*tan(FOV/2)	-6.07
f45/f	12.35	\|Nd5-Nd4\|*100	4.00
				\|CT4-CT5\|*\|α4-α5\|	13.34

as can be seen from the aberration diagrams in fig. 12, the longitudinal spherical aberration, curvature of field, and distortion of the optical system 10 are well controlled, so that the optical system 10 has good imaging quality.

Referring to fig. 13, some embodiments of the present application further provide an image module 20, where the image module 20 includes the optical system 10 and the photosensitive element 210 according to any of the above embodiments, and the photosensitive element 210 is disposed at an image side of the optical system 10. The photosensitive element 210 may be a CCD (Charge Coupled Device) or a CMOS (Complementary metal oxide Semiconductor). Generally, the image forming surface S13 of the optical system 10 overlaps the photosensitive surface of the photosensitive element 210 when assembled.

In some embodiments, the camera module 20 includes a filter 110 disposed between the sixth lens L6 and the photosensitive element 210, and the filter 110 is used for filtering infrared light. In some embodiments, the filter 110 may be mounted to the image end of the lens. In some embodiments, the camera module 20 further includes a protective glass 120, the protective glass 120 is disposed between the filter 110 and the photosensitive element 210, and the protective glass 120 is used for protecting the photosensitive element 210.

Referring to fig. 14, some embodiments of the present application further provide an electronic device 30, and the camera module 20 is applied to the electronic device 30 to enable the electronic device 30 to have a camera function. Specifically, the electronic device 30 includes a fixing member 310, the camera module 20 is mounted on the fixing member 310, and the fixing member 310 may be a circuit board, a middle frame, a protective shell, or the like. The electronic device 30 may be, but is not limited to, a smart phone, a smart watch, an e-book reader, a vehicle-mounted camera device, a monitoring device, a medical device (such as an endoscope), a tablet computer, a biometric device (such as a fingerprint recognition device or a pupil recognition device), a PDA (Personal digital assistant), an unmanned aerial vehicle, and the like. Specifically, in some embodiments, the electronic device 30 is a vehicle-mounted image capturing device (the specific structure can refer to fig. 14), the image capturing module 20 is disposed in a housing of the vehicle-mounted image capturing device, which is a fixing member 310, the fixing member 310 is rotatably connected to a mounting plate 320, and the mounting plate 320 is configured to be fixed to a body of an automobile.

Referring to fig. 15, some embodiments of the present application also provide an automobile 40. When the electronic apparatus 30 is an in-vehicle image pickup apparatus, the electronic apparatus 30 may function as a front-view image pickup apparatus, a rear-view image pickup apparatus, or a side-view image pickup apparatus of the automobile 40. Specifically, the automobile 40 includes a mounting portion 410, and the mount 310 of the electronic device 30 is mounted on the mounting portion 410, and the mounting portion 410 may be a part of a vehicle body, such as an air intake grille, a side view mirror, a rear view mirror, a trunk lid, a roof, and a center console. When the electronic apparatus 30 is provided with the rotatable mounting plate 320, the electronic apparatus 30 is mounted to the mounting portion 410 of the automobile 40 through the mounting plate 320. The electronic device 30 may be mounted on any position of the front side of the vehicle body (e.g., at the air intake grille), the left headlamp, the right headlamp, the left rearview mirror, the right rearview mirror, the trunk lid, the roof, and the like. Secondly, a display device can be arranged in the automobile 40, and the electronic device 30 is in communication connection with the display device, so that images obtained by the electronic device 30 on the installation part 410 can be displayed on the display device in real time, a driver can obtain environment information around the installation part 410 in a wider range, and the driver can drive the automobile more conveniently and safely.

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 fourth lens element with positive refractive power;

a sixth lens element with positive refractive power;

and the optical system satisfies the relationship:

-7≤f1/(Rs2-SAGs2)≤-4；

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

3mm≤f1*f2/f3≤4.5mm；

f2 is the focal length of the second lens, and f3 is the focal length of the third lens.

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

-5≤f2/CT2≤-1；

f2 is the focal length of the second lens, and CT2 is the thickness of the second lens on the optical axis.

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

1.3≤f3/CT3≤2.1；

f3 is the focal length of the third lens, and CT3 is the thickness of the third lens on the optical axis.

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

5≤f45/f≤14；

f45 is the combined focal length of the fourth lens and the fifth lens, and f is the effective focal length of the optical system.

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

|CT4-CT5|*|α4-α5|≤20mm·10^-6/K；

CT4 is the thickness of the fourth lens element on the optical axis, CT5 is the thickness of the fifth lens element on the optical axis, α 4 is the thermal expansion coefficient of the fourth lens element, and α 5 is the thermal expansion coefficient of the fifth lens element.

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

0.5≤f6/CT6≤1.5；

f6 is the focal length of the sixth lens, and CT6 is the thickness of the sixth lens on the optical axis.

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

7≤Imgh/EPD≤10；

imgh is the length of the effective imaging area on the imaging surface of the optical system in the horizontal direction, and EPD is the entrance pupil diameter of the optical system.

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

6≤ΣCT/f≤10；

the sigma-delta CT is the sum of the thicknesses of all lenses in the optical system on the optical axis, and f is the effective focal length of the optical system.

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

-8mm≤f*tan(FOV/2)≤-5mm；

f is the effective focal length of the optical system, and the FOV is the maximum angle of view of the optical system in the horizontal direction of the effective imaging area on the imaging surface.

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

0≤|Nd5-Nd4|*100≤15；

nd4 is a d-line refractive index of the fourth lens, and Nd5 is a d-line refractive index of the fifth lens.

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

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

14. An automobile comprising a mounting portion and the electronic device of claim 13, wherein the electronic device is provided in the mounting portion.