CN114442271A

CN114442271A - Optical system, camera module and electronic equipment

Info

Publication number: CN114442271A
Application number: CN202111591382.6A
Authority: CN
Inventors: 乐宇明; 朱志鹏; 其他发明人请求不公开姓名
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2021-12-23
Filing date: 2021-12-23
Publication date: 2022-05-06
Anticipated expiration: 2041-12-23
Also published as: CN114442271B

Abstract

The invention discloses an optical system, a camera module and electronic equipment. The optical system includes: a first lens element with negative refractive power having a convex object-side surface and a concave image-side surface at paraxial region, respectively; a second lens element with negative refractive power having a concave image-side surface at paraxial region; a third lens element with positive refractive power having convex object-side and image-side surfaces at paraxial region; a fourth lens element with positive refractive power having a convex image-side surface at paraxial region; a fifth lens element and a sixth lens element with refractive power; a seventh lens element with positive refractive power having a convex object-side surface and a convex image-side surface at paraxial region; an eighth lens element with refractive power; the optical system satisfies the relationship: 480deg is less than or equal to (FOV multiplied by TTL)/Imgh is less than or equal to 560 deg. The optical system of the embodiment of the application has wide-angle characteristics, large aperture characteristics and miniaturization design, and can meet the requirements of large-range shooting and high imaging quality.

Description

Optical system, camera module and electronic equipment

Technical Field

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

Background

With the development of the vehicle-mounted industry, technologies such as ADAS (Advanced Driving assistance System), DMS (Driver Monitoring System), OMS (Occupancy Monitoring System), and the like have become mature. The OMS lens extends on the basis of the DMS lens, so that not only a driver is monitored, but also all vehicle personnel can be covered; for example, the OMS is installed in the area between the upper side of the interior rear view mirror and the lower side of the dome lamp, covers the camera of the whole vehicle, can monitor the vehicle interior personnel in real time, and is particularly important as a vehicle interior personnel sensing system for monitoring the safety of children in the vehicle.

However, the wide-angle lens applied to the OMS at present has the defects of poor imaging effect, small image plane, low pixel height, low depth of field and the like; meanwhile, the field angle of the photosensitive chip is small, so that the shooting range of the photosensitive chip is limited. Therefore, how to realize the large-view design of the camera module and simultaneously give consideration to good imaging quality, and ensure the safety of personnel in the vehicle is one of the problems that the industry wants to solve urgently.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the present application provides an optical system that can effectively solve the problem of achieving a large viewing angle design while maintaining good imaging quality.

The invention also provides a camera module in a second aspect.

The third aspect of the present invention further provides an electronic device.

The optical system according to the first aspect of the present application, in order from an object side to an image side along an optical axis, comprises:

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

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

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

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

a fifth lens element with refractive power;

a sixth lens element with refractive power;

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

an eighth lens element with refractive power;

in the optical system, the first lens element has negative refractive power, the object side surface is convex at the paraxial region, and the image side surface is concave at the paraxial region, so that the large-angle light rays entering the first lens element can be grasped favorably, the large-angle image pickup effect can be realized, and the optical system can cover a large visual angle range. The second lens element is arranged in a convex-concave design at a paraxial region, i.e., the object-side surface is convex and the image-side surface is concave, and has negative refractive power to help share the pressure of the negative refractive power of the first lens element, thereby facilitating further converging of incident light, so that large-angle light of the first lens element smoothly enters the second lens element at a reasonable angle, and aberration of the first lens element caused by the large-angle light can be corrected. The object side surface and the image side surface of the third lens element are both convex surfaces at a paraxial region, so that light rays in the central and marginal field of view can be further converged, convergence capacity is provided for light rays in each field of view of the optical system, light rays can be favorably contracted, the total length of the optical system can be favorably compressed, and the positive refractive power of the third lens element can offset aberration generated by an object side lens (namely, the first lens element and the second lens element) with negative refractive power. The image side surface of the fourth lens element with positive refractive power is convex at a paraxial region, so that light can be further converged, and the third lens element with positive refractive power can further counteract aberration to reduce field curvature astigmatism of the optical system. The fifth lens element L5 and the sixth lens element with refractive power can effectively correct the aberration generated by the light passing through the object lens elements (i.e. the first lens element to the fourth lens element), and reduce the correction pressure of the rear lens elements (i.e. the seventh lens element and the eighth lens element). The object side surface and the image side surface of the seventh lens element with positive refractive power are convex surfaces, so that the light entering amount of light passing through the diaphragm can be effectively controlled, the relative illumination is increased, and the brightness of an imaging surface is improved. In addition, the eighth lens element closest to the imaging surface has refractive power, so that the incident angle of incident light on the imaging surface can be reduced, the generation of chromatic aberration is reduced, and the imaging quality of the optical system is improved.

The optical system satisfies the relationship:

480deg≤(FOV×TTL)/Imgh≤560deg；

the FOV is the maximum field angle of the optical system, the TTL is the distance between the object side surface of the first lens and the imaging surface of the optical system on the optical axis, and the Imgh is the image height corresponding to the maximum field angle of the optical system.

Through satisfying the conditional expression, be favorable to realizing big image plane effect to do benefit to the sensitization chip who matches high pixel, promoted optical system's image plane definition also does benefit to realize big visual angle and makes a video recording simultaneously, and the light of wide angle is penetrated and is makeed optical system has wide angle characteristic, and then can improve the imaging quality. When the angle of view of the optical system is lower than the lower limit of the conditional expression, the large-angle-of-view image pickup required by the image pickup system such as an OMS (object-oriented system) is not facilitated, and therefore the safety monitoring cannot be achieved; if the maximum field angle of the optical system exceeds the upper limit of the conditional expression, the image height corresponding to the maximum field angle of the optical system is small, that is, the image plane is small, so that the field imaging range of the optical system is reduced, the large image plane effect is not realized, and the imaging quality is reduced.

In one embodiment, the optical system satisfies the relationship:

2≤SD11/SAGs11≤3.3；

SD11 is half the maximum effective aperture of the first lens object-side surface, SAGs11 is the sagittal height of the first lens object-side surface at the maximum effective aperture.

Through satisfying the conditional expression, can avoid the object side face type of first lens is too crooked, on satisfying the basis that wide-angle light was collected, has reduced the shaping and the processing degree of difficulty of first lens are favorable to controlling simultaneously optical system's head size has compressed optical system's volume does benefit to the equipment and realizes miniaturized design. Below the conditional lower limit, the object-side edge height of the first lens is too large, so that the surface shape of the first lens is too curved, and the lens processing difficulty is increased; when the maximum effective caliber of the object side surface of the first lens is over the upper limit of the conditional expression, the size reduction of the caliber of the head part of the optical system is not facilitated, and therefore the assembly molding is not facilitated.

In one embodiment, the optical system satisfies the relationship:

0.6≤|f12/f|≤1.3；

f12 is the combined focal length of the first and second lenses, and f is the effective focal length of the optical system.

By satisfying the conditional expression, the ratio relation between the combined focal length of the first lens and the second lens and the effective focal length of the optical system is reasonably controlled, so that the refractive power of the object side lens group is reasonably distributed in the whole optical system, the convergence of light beams of the object side lens group of the optical system is favorably controlled, large-angle view field light rays can conveniently enter the optical system, and the wide-angle characteristic of the optical system is ensured. If the refractive power of the first lens element and the second lens element is insufficient beyond the upper limit of the conditional expression, the light with large angle is difficult to enter the optical system, which is not favorable for expanding the field angle range of the optical system; when the refractive power of the first lens element and the second lens element is too strong, the first lens element and the second lens element are prone to generate strong astigmatism and chromatic aberration, which is not favorable for achieving high-resolution imaging of the optical system.

In one embodiment, the optical system satisfies the relationship:

44deg/mm≤FOV/f≤50deg/mm；

f is the effective focal length of the optical system.

Satisfying above-mentioned conditional expression, being favorable to for optical system provides big angle of view to can effectively promote the area of finding a view of shooing the picture, and optical system's reasonable refractive power configuration, even optical system's effective focal length value is reasonable, when satisfying can hold more area of getting for instance, optical system's effective focal length is unlikely to undersize or too big, can make the picture of making a video recording effectively match with sensitization chip, thereby accomplishes high-quality formation of image. When the angle of view of the optical system is lower than the lower limit of the conditional expression, the required angle of view cannot be reached due to the fact that the shooting angle of view of the optical system is too small, and the view finding area of a shot picture is affected; above the upper limit of the conditional expression, the effective focal length of the optical system is too small, which results in too large refractive power of the optical system and severe surface curvature of each lens, thus being unfavorable for production molding and assembly.

In one embodiment, the optical system satisfies the relationship:

2≤ImgH/SD82≤3；

SD82 is half the maximum effective aperture of the image-side surface of the eighth lens.

The eighth lens is used as the lens closest to the imaging surface, the caliber size of the eighth lens influences the tail size of the optical system, the ratio relation between the maximum effective caliber of the image side surface of the eighth lens and the image height of the optical system is controlled by meeting a conditional expression, the caliber size of the eighth lens can be controlled, and therefore the tail caliber size of the optical system is controlled conveniently, the size of the optical system is compressed, and the miniaturization design is achieved. When the image height of the optical system is lower than the conditional lower limit, the image height of the optical system is too small, the effective matching of an imaging surface and a photosensitive chip is not facilitated, and the problems of dark angles, low illumination and the like are easily caused; and when the maximum effective aperture of the image side surface of the eighth lens exceeds the upper limit of the conditional expression, the maximum effective aperture is too large, so that the aim of realizing the miniaturization of the whole structure of the optical system is not facilitated.

In one embodiment, the optical system satisfies the relationship:

1.5≤f3/f≤5.5；

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

By satisfying the conditional expression, the third lens provides positive refractive power for the optical system, and by controlling the ratio relationship between the effective focal length of the third lens and the effective focal length of the optical system, the wide-angle and high-image-quality imaging of the optical system can be realized. When the effective focal length of the third lens element is too large and the refractive power of the middle part of the optical system is insufficient, the captured large-angle light is difficult to smoothly enter the rear lens group of the optical system, which is not favorable for expanding the field angle range of the optical system; below the lower limit of the conditional expression, the refractive power of the third lens element is too strong, which causes the lens surface to be too curved, and is liable to generate strong astigmatism and chromatic aberration, thereby being unfavorable for realizing the high-resolution imaging characteristic of the optical system.

In one embodiment, the optical system satisfies the relationship:

220≤OD/f≤250；

OD is the distance between the object of the optical system and the object side surface of the first lens on the optical axis, and f is the effective focal length of the optical system.

By satisfying the conditional expression, the relation between the object distance and the effective focal length of the optical system can be controlled, thereby being beneficial to ensuring the field depth range of the optical system and satisfying the field depth requirement for monitoring the shooting environment. When the distance is lower than the lower limit of the conditional expression, the object distance of the optical system during focusing is shortened, so that the depth of field is insufficient, and the large-scale monitoring of the shooting environment is difficult to realize; when the upper limit of the conditional expression is exceeded, the effective focal length of the optical system is too small, which is not beneficial to the reasonable distribution of the refractive power among the lenses, so that the focusing can not be better performed, and the imaging effect is influenced.

In one embodiment, the optical system satisfies the relationship:

23≤TTL/CT2≤38.2；

CT2 is the thickness of the second lens on the optical axis.

By satisfying the conditional expression, the relation between the central thickness of the second lens and the optical total length of the optical system can be reasonably controlled, the optical total length of the optical system is favorably controlled, the whole structure is compact, and meanwhile, the large visual angle required by monitoring the shooting environment is favorably realized. When the thickness of the second lens is lower than the lower limit of the relational expression, the thickness of the second lens is too large, and ghost is easily generated on the reflection of the collected light of the first lens, so that the quality of a monitored picture is influenced; exceeding the upper limit of the conditional expression, the total optical length of the optical system is too long, which is not beneficial to miniaturization, and leads to the difficulty of installing the optical system in the camera module.

The camera module according to the second aspect of the present application includes a photosensitive chip and the optical system described above, where the photosensitive chip is disposed on the image side of the optical system. Through adopting above-mentioned optical system, the module of making a video recording has wide angle characteristic, big light ring characteristic and miniaturized design, can satisfy and shoot and high imaging quality's demand on a large scale.

According to the third aspect of the present application, the electronic device includes a fixing member and the camera module set, and the camera module set is disposed on the fixing member. The camera module can realize wide-angle characteristics, large aperture characteristics and miniaturization design, and can meet the requirements of large-range shooting and high imaging quality.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

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 view of a camera module according to an embodiment of the present application;

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

FIG. 13 is a schematic structural diagram of an automobile according to an embodiment of the present application;

reference numerals:

the optical system 10, the camera module 20, the electronic apparatus 30, the automobile 40, the vehicle body 410,

the optical axis 101, the optical filter 110, the photosensitive chip 210, the fixing member 310,

stop STO, first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, sixth lens L6, seventh lens L7, eighth lens L8,

a first lens object-side surface S1, a first lens image-side surface S2, a second lens object-side surface S3, a second lens image-side surface S4, a third lens object-side surface S5, a third lens image-side surface S6, a fourth lens object-side surface S7, a fourth lens image-side surface S8, a fifth lens object-side surface S9, a fifth lens image-side surface S10, a sixth lens object-side surface S11, a sixth lens image-side surface S12, a seventh lens object-side surface S13, a seventh lens image-side surface S14, an eighth lens object-side surface S15, an eighth lens image-side surface S16, a filter object-side surface S17, a filter image-side surface S18, and an image-forming surface S19.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

An optical system 10 according to one embodiment of the present invention will be described below with reference to the drawings.

Referring to fig. 1, an optical system 10 with an eight-lens design is provided, wherein the optical system 10 includes, in order from an object side to an image side along an optical axis 101, 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 fourth lens element L4 with positive refractive power, a fifth lens element L5 with positive refractive power or negative refractive power, a sixth lens element L6 with positive refractive power or negative refractive power, a seventh lens element L7 with positive refractive power, and an eighth lens element L8 with positive refractive power or negative refractive power. The lenses in the optical system 10 should be arranged coaxially, the common axis of the lenses is the optical axis 101 of the optical system 10, and the lenses can be mounted in a lens barrel to form an image pickup lens.

The first lens L1 has an object side surface S1 and an image side surface S2, the second lens L2 has an object side surface S3 and an image side surface S4, the third lens L3 has an object side surface S5 and an image side surface S6, the fourth lens L4 has an object side surface S7 and an image side surface S8, the fifth lens L5 has an object side surface S9 and an image side surface S10, the sixth lens L6 has an object side surface S11 and an image side surface S12, the seventh lens L7 has an object side surface S13 and an image side surface S14, and the eighth lens L8 has an object side surface S15 and an image side surface S16. Meanwhile, the optical system 10 further has an image plane S19, the image plane S19 is located on the image side of the eighth lens element L8, and light rays emitted from an on-axis object point at a corresponding object distance can be converged on the image plane S19 after being adjusted by each lens element of the optical system 10.

Generally, the imaging surface S19 of the optical system 10 coincides with the photosensitive surface of the photosensitive chip. It should be noted that in some embodiments, the optical system 10 may be matched with an image sensor having a rectangular photosensitive surface, and the imaging surface S19 of the optical system 10 coincides with the rectangular photosensitive surface of the image sensor. At this time, the effective pixel area on the imaging surface S19 of the optical system 10 has a horizontal direction, a vertical direction, and a diagonal direction, and in this application, the maximum angle of view of the optical system 10 is understood to be the maximum angle of view of the optical system 10 in the diagonal direction, and the image height corresponding to the maximum angle of view is understood to be half the length of the effective pixel area on the imaging surface S19 of the optical system 10 in the diagonal direction.

In the embodiment of the present application, the object-side surface S1 of the first lens element L1 is convex at the paraxial region 101, and the image-side surface S2 is concave at the paraxial region 101; the image-side surface S4 of the second lens element L2 is concave at the paraxial region 101; the object-side surface S5 of the third lens element L3 is convex at the paraxial region 101, and the image-side surface S6 is convex at the paraxial region 101; the image-side surface S8 of the fourth lens element L4 is convex at the paraxial region 101; the object-side surface S13 of the seventh lens element L7 is convex at the paraxial region 101, and the image-side surface S14 is convex at the paraxial region 101. When describing a lens surface having a certain profile near the optical axis 101, i.e., the lens surface has such a profile near the optical axis 101; when describing a lens surface as having a profile near the maximum effective aperture, the lens surface has the profile radially and near the maximum effective clear aperture.

In the optical system 10, the first lens element L1 with negative refractive power has a convex object-side surface S1 at the paraxial region 101 and a concave image-side surface at the paraxial region 101, which is beneficial for capturing the large-angle light rays incident on the first lens element L1, thereby achieving a large-angle image capturing effect and facilitating the optical system 10 to cover a large viewing angle range. The second lens element L2 is disposed with a convex-concave design at the paraxial region 101, i.e., the object-side surface S3 is convex and the image-side surface S4 is concave, and has negative refractive power to help share the negative refractive power pressure of the first lens element L1, so as to further converge the incident light, so that the large-angle light of the first lens element L1 can smoothly enter the second lens element L2 at a reasonable angle, and the aberration of the first lens element L1 caused by the large-angle light can be corrected. The object-side surface S5 and the image-side surface S6 of the third lens element L3 are both convex at the paraxial region 101, so that the light rays in the central and peripheral fields can be further converged, thereby providing the converging capability for the light rays in each field of the optical system 10, facilitating the contraction of the light rays, facilitating the compression of the total length of the optical system 10, and having positive refractive power, which can counteract the aberration generated by the object-side lens elements with negative refractive power (i.e., the first lens element L1 and the second lens element L2). The image-side surface S8 of the fourth lens element L4 with positive refractive power is convex at a paraxial region 101, so as to further converge light rays, and cooperate with the third lens element L3 with positive refractive power to further counteract aberration and reduce field curvature astigmatism of the optical system 10. The fifth lens element L5 and the sixth lens element with refractive power can effectively correct the aberration generated by the light passing through the object lens element (i.e. the first lens element L1 to the fourth lens element L4), and reduce the correction pressure of the rear lens element (i.e. the seventh lens element L7 and the eighth lens element L8). The object-side surface S13 and the image-side surface S14 of the seventh lens element L7 with positive refractive power are convex, so that the amount of light entering through the stop can be effectively controlled, the relative illumination is increased, and the brightness of the image plane S19 is improved. In addition, the eighth lens element L8 closest to the image plane S19 has refractive power, so that the incident angle of the incident light on the image plane S19 can be reduced, and the occurrence of chromatic aberration is reduced, thereby improving the imaging quality of the optical system 10.

In one embodiment, the optical system 10 satisfies the relationship:

480deg≤(FOV×TTL)/Imgh≤560deg；

the FOV is the maximum angle of view of the optical system 10, TTL is the distance on the optical axis 101 from the object-side surface S1 of the first lens element L1 to the image forming surface S19 of the optical system 10, and Imgh is the image height corresponding to the maximum angle of view of the optical system 10.

Through satisfying the conditional expression, be favorable to realizing big image plane effect to do benefit to the sensitization chip who matches high pixel, promoted optical system 10's image plane definition, satisfy the conditional expression simultaneously and also do benefit to and realize large visual angle and make a video recording, the light of wide angle is penetrated and is gone into and can be made optical system 10 have wide angle characteristic, and then can improve the imaging quality. In some embodiments, this embodiment that optical system 10 satisfies may be specifically 487.273, 494.545, 501.818, 509.091, 516.364, 523.636, 530.909, 538.182, 545.455, or 552.727. Below the lower limit of the conditional expression, the field angle of the optical system 10 is small, which is not beneficial to the large field angle image pickup required by the image pickup systems such as the OMS, and thus the safety monitoring cannot be achieved; if the maximum field angle of the optical system 10 exceeds the upper limit of the conditional expression, the image height corresponding to the maximum field angle is small, that is, the image plane S19 is small, which reduces the field imaging range of the optical system 10, is not favorable for achieving a large image plane effect, and reduces the imaging quality.

It should be noted that in some embodiments, the optical system 10 may be matched to a photosensitive chip having a rectangular photosensitive surface, and the imaging surface S19 of the optical system 10 coincides with the photosensitive surface of the photosensitive element. At this time, the effective pixel region on the imaging plane S19 of the optical system 10 has a horizontal direction and a diagonal direction, the maximum angle of view of the optical system 10 can be understood as the maximum angle of view of the optical system 10 in the diagonal direction, and ImgH can be understood as half the length of the effective pixel region on the imaging plane S19 of the optical system 10 in the diagonal direction.

In one embodiment, the optical system 10 satisfies the relationship:

2≤SD11/SAGs11≤3.3；

SD11 is half the maximum effective aperture of the first lens L1 object side S1, SAGs11 is the rise of the object side S1 of the first lens L1 at the maximum effective aperture.

Through satisfying the conditional expression, can avoid the too crooked of object side S1 face type of first lens L1, on satisfying the basis that wide-angle light was collected, reduced the shaping of first lens L1 and the processing degree of difficulty, be favorable to controlling optical system 10 'S head size simultaneously, compressed optical system 10' S volume, do benefit to the equipment and realize miniaturized design. In some embodiments, this embodiment that is satisfied by optical system 10 may be specifically 2.118, 2.236, 2.355, 2.473, 2.591, 2.709, 2.827, 2.945, 3.064, or 3.182. Below the conditional lower limit, the rise of the object-side surface S1 of the first lens L1 is too large, so that the surface form of the first lens L1 is too curved, resulting in increased difficulty in lens processing; exceeding the upper limit of the conditional expression, the maximum effective aperture of the object-side surface S1 of the first lens L1 is too large, which is disadvantageous for the size reduction of the head aperture of the optical system 10, and is disadvantageous for the assembly molding.

In one embodiment, the optical system 10 satisfies the relationship:

0.6≤|f12/f|≤1.3；

f12 is the combined focal length of the first lens L1 and the second lens L2, and f is the effective focal length of the optical system 10.

By satisfying the conditional expressions, the ratio relationship between the combined focal length of the first lens element L1 and the second lens element L2 and the effective focal length of the optical system 10 is reasonably controlled, so that the refractive power of the object side lens assembly is reasonably distributed in the whole optical system 10, the convergence of the light beams of the object side lens assembly of the optical system 10 is favorably controlled, the light beams with a large angle of view field are conveniently incident into the optical system 10, and the wide-angle characteristic of the optical system 10 is ensured. In some embodiments, this embodiment satisfied by optical system 10 may be specifically 0.664, 0.727, 0.791, 0.855, 0.918, 0.982, 1.045, 1.109, 1.173, or 1.236. If the refractive powers of the first lens element L1 and the second lens element L2 are insufficient beyond the upper limit of the conditional expression, the light with large angle is difficult to enter the optical system 10, which is not favorable for expanding the field angle range of the optical system 10; below the lower limit of the conditional expression, the refractive powers of the first lens element L1 and the second lens element L2 are too strong, which is likely to generate strong astigmatism and chromatic aberration, and is not favorable for realizing high-resolution imaging of the optical system 10.

In one embodiment, the optical system 10 satisfies the relationship:

44deg/mm≤FOV/f≤50deg/mm；

f is the effective focal length of the optical system 10.

Satisfying above-mentioned conditional expression, being favorable to providing big angle of view for optical system 10 to can effectively promote the area of finding a view of shooing the picture, and the configuration of the reasonable refractive power of optical system 10, even the effective focal length value of optical system 10 is reasonable, when satisfying and can hold more area of getting for instance, optical system 10's effective focal length is unlikely to undersize or too big, can make the picture of making a video recording effectively match with sensitization chip, thereby accomplishes high-quality formation of image. In some embodiments, this embodiment that optical system 10 satisfies may be specifically 44.545, 45.091, 45.636, 46.182, 46.727, 47.273, 47.818, 48.364, 48.909, or 49.455. Below the lower limit of the conditional expression, the shooting angle of view of the optical system 10 is too small to reach the required angle of view, thereby affecting the viewing area of the shot picture; above the upper limit of the conditional expression, the effective focal length of the optical system 10 is too small, which results in too large refractive power of the optical system 10 and severe surface curvature of each lens, thereby being unfavorable for production molding and assembly.

In one embodiment, the optical system 10 satisfies the relationship:

2≤ImgH/SD82≤3；

SD82 is half the maximum effective aperture of the image-side surface S16 of the eighth lens L8.

Because the eighth lens element L8 is the lens element closest to the image plane S19, the aperture size of the eighth lens element L8 is controlled to match the ratio of the maximum effective aperture of the image side surface S16 of the eighth lens element L8 to the image height of the optical system 10 by satisfying the conditional expression, and the aperture size of the eighth lens element L8 can be controlled, thereby facilitating the control of the aperture size of the rear portion of the optical system 10, reducing the volume of the optical system 10, and achieving the compact design. In some embodiments, the embodiment that optical system 10 satisfies may be specifically 2.091, 2.182, 2.273, 2.364, 2.455, 2.545, 2.636, 2.727, 2.818, or 2.909. Below the lower limit of the conditional expression, the image height of the optical system 10 is too small, which is not favorable for the effective matching of the imaging surface S19 and the photosensitive chip, and is easy to generate dark corners, low illumination and other problems; exceeding the upper limit of the conditional expression, the maximum effective aperture of the image-side surface S16 of the eighth lens L8 is too large, which is disadvantageous for the purpose of downsizing the entire structure of the optical system 10.

In one embodiment, the optical system 10 satisfies the relationship:

1.5≤f3/f≤5.5；

f3 is the effective focal length of the third lens L3, and f is the effective focal length of the optical system 10.

By satisfying the conditional expressions, the third lens element L3 provides positive refractive power for the optical system 10, and by controlling the ratio relationship between the effective focal length of the third lens element L3 and the effective focal length of the optical system 10, the optical system 10 is facilitated to realize wide-angle and high-quality imaging. In some embodiments, the embodiment that optical system 10 satisfies may be specifically 1.864, 2.227, 2.591, 2.955, 3.318, 3.682, 4.045, 4.409, 4.773, or 5.136. If the effective focal length of the third lens element L3 is too large and the refractive power of the middle portion of the optical system 10 is insufficient, the captured large-angle light is difficult to smoothly enter the rear lens group of the optical system 10, which is not favorable for expanding the field angle range of the optical system 10; below the lower limit of the conditional expression, the refractive power of the third lens element L3 is too strong, which results in too much curvature of the lens surface, and is liable to generate strong astigmatism and chromatic aberration, thereby being unfavorable for realizing the high-resolution imaging characteristic of the optical system 10.

In one embodiment, the optical system 10 satisfies the relationship:

220≤OD/f≤250；

OD is the distance on the optical axis 101 between the object of the optical system 10 and the object-side surface S1 of the first lens L1, and f is the effective focal length of the optical system 10.

By satisfying the conditional expression, the relation between the object distance and the effective focal length of the optical system 10 can be controlled, which is beneficial to ensuring the field depth range of the optical system 10 and satisfying the field depth requirement for monitoring the shooting environment. In some embodiments, the embodiment that optical system 10 satisfies may be specifically 222.727, 225.455, 228.182, 230.909, 233.636, 236.364, 239.091, 241.818, 244.545, or 247.273. When the distance is lower than the lower limit of the conditional expression, the object distance of the optical system 10 during focusing is shortened, so that the depth of field is insufficient, and the large-scale monitoring of the shooting environment is difficult to realize; if the upper limit of the conditional expression is exceeded, the effective focal length of the optical system 10 is too small, which is not favorable for the reasonable distribution of refractive power between the lenses, and therefore, the focusing cannot be performed better, thereby affecting the imaging effect.

In one embodiment, the optical system 10 satisfies the relationship:

23≤TTL/CT2≤38.2；

CT2 is the thickness of the second lens element L2 on the optical axis 101.

By satisfying the conditional expression, the relation between the central thickness of the second lens L2 and the optical total length of the optical system 10 can be reasonably controlled, which is beneficial to controlling the optical total length of the optical system 10, so that the whole structure is compact, and meanwhile, the large viewing angle required for monitoring the shooting environment is beneficial to being realized. In some embodiments, this embodiment satisfied by optical system 10 may be specifically 24.382, 25.764, 27.145, 28.527, 29.909, 31.291, 32.673, 34.055, 35.436, or 36.818. Below the lower limit of the relational expression, the thickness of the second lens L2 is too large, which is easy to generate ghost image to the collected light of the first lens L1, thereby affecting the quality of the monitored picture; exceeding the upper limit of the conditional expression, the total optical length of the optical system 10 is too long, which is disadvantageous for miniaturization, and makes it difficult to mount the optical system 10 in the camera module.

The effective focal length in the above relation is at least 486nm, the effective focal length is at least the value of the corresponding lens at the paraxial region 101, and the refractive power of the lens is at least the value at the paraxial region 101. And the above relationship conditions and the technical effects thereof are directed to the optical system 10 having the above lens design. When the lens design (the number of lenses, the refractive power arrangement, the surface type arrangement, etc.) of the optical system 10 cannot be ensured, it is difficult to ensure that the optical system 10 can still have the corresponding technical effect when the relational expressions are satisfied, and even the imaging performance may be significantly reduced.

In some embodiments, at least one lens in the optical system 10 may have a spherical surface shape, and the design of the spherical surface shape may reduce the difficulty and cost of manufacturing the lens. In some embodiments, at least one lens of the optical system 10 may also have an aspheric surface, which may be referred to as having an aspheric surface when at least one side surface (object side surface or image side surface) of the lens is aspheric. In one embodiment, both the object-side surface and the image-side surface of each lens can be designed to be aspheric. The aspheric design can help the optical system 10 to eliminate the aberration more effectively, improving the imaging quality. In some embodiments, the design of each lens surface in the optical system 10 may be configured by spherical and aspherical surface types in order to take into account the manufacturing cost, the manufacturing difficulty, the imaging quality, the assembly difficulty, and the like.

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

where Z is a distance from a corresponding point on the aspheric surface to a tangent plane of the aspheric surface at the optical axis 101, r is a distance from the corresponding point on the aspheric surface to the optical axis 101, c is a curvature of the aspheric surface at the optical axis 101, k is a conic coefficient, and Ai is a high-order term coefficient corresponding to the ith high-order term in the aspheric surface type formula.

It should also be noted that when a lens surface is aspheric, there may be points of inflection where the surface will change in shape in the radial direction, such as where one lens surface is convex near the optical axis 101 and concave near the maximum effective aperture. The planar design of the reverse curvature point can realize good correction on field curvature and distortion aberration of the edge field in the optical system 10, and improve imaging quality.

In some embodiments, at least one lens of the optical system 10 is made of Glass (GL). For example, the first lens L1 closest to the object side may be made of glass, and the effect of the glass material of the first lens L1 on eliminating temperature drift may be utilized to effectively reduce the influence of the ambient temperature change on the optical system 10, thereby maintaining a better and more stable imaging quality. In some embodiments, the material of at least one lens in the optical system 10 may also be Plastic (PC), and the Plastic material may be polycarbonate, gum, etc. The lens made of plastic can reduce the production cost of the optical system 10, and the lens made of glass can endure higher or lower temperature and has excellent optical effect and better stability. In some embodiments, lenses of different materials may be disposed in the optical system 10, that is, a design combining a glass lens and a plastic lens may be adopted, but the specific configuration relationship may be determined according to practical requirements and is not exhaustive here.

It is to be noted that the first lens L1 does not mean that there is only one lens, and in some embodiments, there may be two or more lenses in the first lens L1, and the two or more lenses can form a cemented lens, and a surface of the cemented lens closest to the object side can be regarded as the object side surface S1, and a surface of the cemented lens closest to the image side can be regarded as the image side surface S2. Alternatively, although no cemented lens is formed between the lenses of the first lens L1, the distance between the lenses is relatively fixed, and in this case, the object-side surface of the lens closest to the object side is the object-side surface S1, and the image-side surface of the lens closest to the image side is the image-side surface S2. In addition, the number of lenses in the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5 or the sixth lens L6 in some embodiments may also be greater than or equal to two, and a cemented lens may be formed between any two adjacent lenses, and may also be a non-cemented lens.

In some embodiments, the optical system 10 further includes an aperture stop STO, which may also be a field stop, for controlling the light incident amount and the depth of field of the optical system 10, and achieving good interception of the ineffective light to improve the imaging quality of the optical system 10, and the aperture stop STO may be disposed between the object side of the optical system 10 and the object side surface S1 of the first lens L1. It is understood that, in other embodiments, the stop STO may also be disposed between two adjacent lenses, for example, between the third lens L3 and the fourth lens L4, or between the fourth lens L4 and the fifth lens L5, and the arrangement is adjusted according to practical situations, which is not specifically limited in this embodiment of the present application. The aperture stop STO may also be formed by a holder that holds the lens.

The optical system 10 of the present application is illustrated by the following more specific 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 along an optical axis 101, 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 fourth lens element L4 with positive refractive power, an aperture stop STO, a fifth lens element L5 with positive refractive power, a sixth lens element L6 with negative refractive power, a seventh lens element L7 with positive refractive power, and an eighth lens element L8 with negative refractive power. The respective lens surface types of the optical system 10 are as follows:

the object-side surface S1 of the first lens element L1 is convex at the paraxial region 101, and the image-side surface S2 is concave at the paraxial region 101;

the object-side surface S3 of the second lens element L2 is convex at the paraxial region 101, and the image-side surface S4 is concave at the paraxial region 101;

the object-side surface S5 of the third lens element L3 is convex at the paraxial region 101, and the image-side surface S6 is convex at the paraxial region 101;

the object-side surface S7 of the fourth lens element L4 is concave at the paraxial region 101, and the image-side surface S8 is convex at the paraxial region 101;

the object-side surface S9 of the fifth lens element L5 is convex at the paraxial region 101, and the image-side surface S10 is convex at the paraxial region 101;

the object-side surface S11 of the sixth lens element L6 is concave at the paraxial region 101, and the image-side surface S12 is convex at the paraxial region 101;

the object-side surface S13 of the seventh lens element L7 is convex at the paraxial region 101, and the image-side surface S14 is convex at the paraxial region 101;

the object-side surface S15 of the eighth lens element L8 is concave at the paraxial region 101, and the image-side surface S16 is convex at the paraxial region 101.

Further, in this embodiment, the aperture stop STO is located between the fourth lens L4 and the fifth lens L5, and the image-side surface S10 of the fifth lens L5 is cemented with the object-side surface S11 of the sixth lens L6, that is, the fifth lens L5 and the sixth lens L6 form a cemented element, and by the arrangement of the cemented element, the accumulated tolerance of the two lenses is set to the tolerance of one cemented lens, so that the decentering sensitivity of the lenses can be reduced, the assembly sensitivity of the optical lens can be reduced, the problem of difficulty in lens processing and manufacturing and lens assembly is solved, and the yield of the optical lens is improved.

In the first embodiment, each of the first lens L1 to the eighth lens L8 has a spherical surface, and each of the first lens L1 to the eighth lens L8 is made of Glass (GL). The optical system 10 further includes a filter 110, the filter 110 can be a part of the optical system 10 or can be removed from the optical system 10, but when the filter 110 is removed, the total optical length TTL of the optical system 10 remains unchanged; in the embodiment, the optical filter 110 is an infrared cut-off filter, and the infrared cut-off filter is disposed between the image side surface S14 of the seventh lens L7 and the imaging surface S19 of the optical system 10, so as to filter out light rays in invisible wave bands such as infrared light, and only allow visible light to pass through, so as to obtain a better image effect; it is understood that the filter 110 can also filter out light in other bands, such as visible light, and only let infrared light pass through, and the optical system 10 can be used as an infrared optical lens, that is, the optical system 10 can also image and obtain better image effect in a dark environment and other special application scenes.

The lens parameters of the optical system 10 in the first embodiment are shown in table 1 below. The elements of the optical system 10 lying from the object side to the image side are arranged in the order from top to bottom in table 1, the diaphragm representing the aperture stop STO. The Y radius in table 1 is the radius of curvature of the corresponding surface of the lens at the optical axis 101. In table 1, the surface with the surface number S1 represents the object-side surface of the first lens L1, the surface with the surface number S2 represents the image-side surface of the first lens L1, and so on. The absolute value of the first value of the lens in the "thickness" parameter list is the thickness of the lens on the optical axis 101, and the absolute value of the second value is the distance from the image-side surface of the lens to the next optical surface (the object-side surface or stop surface of the next lens) on the optical axis 101, wherein the stop thickness parameter represents the distance from the stop surface to the object-side surface of the adjacent lens on the image side on the optical axis 101. In the table, the reference wavelength of the refractive index and the abbe number of each lens is 587.6nm, the reference wavelength of the focal length (effective focal length) is 486nm, and the numerical units of the Y radius, the thickness, and the focal length (effective focal length) are millimeters (mm). In addition, the parameter data and the lens surface shape structure used for the relational expression calculation in the following embodiments are subject to the data in the lens parameter table in the corresponding embodiment.

TABLE 1

As can be seen from table 1, the effective focal length f of the optical system 10 in the first embodiment is 3.459mm, the f-number FNO is 2.000, the total optical length TTL is 34.210mm, the total optical length TTL in the following embodiments is the sum of the thickness values corresponding to the surface numbers S1 to S17, and the maximum field angle FOV of the optical system 10 is 153.585 °, which indicates that the optical system 10 in this embodiment has a large field angle.

Further, in the first embodiment, the optical system 10 satisfies the following relationships:

(FOV × TTL)/Imgh is 550.063 deg; the FOV is the maximum angle of view of the optical system 10, TTL is the distance on the optical axis 101 from the object-side surface S1 of the first lens element L1 to the image forming surface S19 of the optical system 10, and Imgh is the image height corresponding to the maximum angle of view of the optical system 10. Through satisfying the conditional expression, be favorable to realizing big image plane effect to do benefit to the sensitization chip who matches high pixel, promoted optical system 10's image plane definition, satisfy the conditional expression simultaneously and also do benefit to and realize large visual angle and make a video recording, the light of wide angle is penetrated and is gone into and can be made optical system 10 have wide angle characteristic, and then can improve the imaging quality.

SD11/SAGs11 ═ 2.997; SD11 is half the maximum effective aperture of the first lens L1 object side S1, SAGs11 is the rise of the object side S1 of the first lens L1 at the maximum effective aperture. The condition formula is satisfied, the object side S1 face type of first lens L1 can be avoided too much bending, on the basis that satisfies big-angle light collection, the shaping of first lens L1 has been reduced and the processing degree of difficulty, is favorable to controlling optical system 10 'S head size simultaneously, has compressed optical system 10' S volume, does benefit to the equipment and realizes miniaturized design.

1.083, | f12/f |; f12 is the combined focal length of the first lens L1 and the second lens L2, and f is the effective focal length of the optical system 10. By satisfying the conditional expressions, the ratio relationship between the combined focal length of the first lens element L1 and the second lens element L2 and the effective focal length of the optical system 10 is reasonably controlled, so that the refractive power of the object side lens assembly is reasonably distributed in the whole optical system 10, the convergence of the light beams of the object side lens assembly of the optical system 10 is favorably controlled, the light beams with a large angle of view field are conveniently incident into the optical system 10, and the wide-angle characteristic of the optical system 10 is ensured.

FOV/f is 44.402 deg/mm; f is the effective focal length of the optical system 10. Satisfying above-mentioned conditional expression, being favorable to providing big angle of view for optical system 10 to can effectively promote the area of finding a view of shooing the picture, and the configuration of the reasonable refractive power of optical system 10, even the effective focal length value of optical system 10 is reasonable, when satisfying and can hold more area of getting for instance, optical system 10's effective focal length is unlikely to undersize or too big, can make the picture of making a video recording effectively match with sensitization chip, thereby accomplishes high-quality formation of image.

ImgH/SD82 ═ 2.544; SD82 is half the maximum effective aperture of the image-side surface S16 of the eighth lens L8. Because the eighth lens element L8 is the lens element closest to the image plane S19, the aperture size of the eighth lens element L8 is controlled to match the ratio of the maximum effective aperture of the image side surface S16 of the eighth lens element L8 to the image height of the optical system 10 by satisfying the conditional expression, and the aperture size of the eighth lens element L8 can be controlled, thereby facilitating the control of the aperture size of the rear portion of the optical system 10, reducing the volume of the optical system 10, and achieving the compact design.

f3/f 2.205; f3 is the effective focal length of the third lens L3, and f is the effective focal length of the optical system 10. By satisfying the conditional expressions, the third lens element L3 provides positive refractive power for the optical system 10, and by controlling the ratio relationship between the effective focal length of the third lens element L3 and the effective focal length of the optical system 10, the optical system 10 is facilitated to realize wide-angle and high-quality imaging.

OD/f 231.281; OD is the distance on the optical axis 101 between the object of the optical system 10 and the object-side surface S1 of the first lens L1, and f is the effective focal length of the optical system 10. By satisfying the conditional expression, the relation between the object distance and the effective focal length of the optical system 10 can be controlled, which is beneficial to ensuring the field depth range of the optical system 10 and satisfying the field depth requirement for monitoring the shooting environment.

TTL/CT2 is 38.012; CT2 is the thickness of the second lens L2 on the optical axis 101. By satisfying the conditional expressions, the relation between the central thickness of the second lens L2 and the optical total length of the optical system 10 can be reasonably controlled, which is beneficial to controlling the optical total length of the optical system 10, so that the overall structure is compact, and meanwhile, the realization of a large viewing angle required for monitoring the shooting environment is facilitated.

Fig. 2 includes a longitudinal spherical aberration diagram, an astigmatism diagram, and a distortion diagram of the optical system 10 in the first embodiment. Wherein the reference wavelength of the astigmatism and distortion plots is 486 nm. Longitudinal Spherical Aberration diagrams (Longitudinal Spherical Aberration) show the convergent focus deviation of light rays of different wavelengths through the lens. The ordinate of the longitudinal spherical aberration diagram represents Normalized Pupil coordinates (Normalized Pupil coordmator) from the Pupil center to the Pupil edge, and the abscissa represents the distance (in mm) of the imaging plane S19 to the intersection of the ray and the optical axis. It can be known from the longitudinal spherical aberration diagram that the convergent focus deviation degrees of the light rays with the respective wavelengths in the first embodiment tend to be consistent, the maximum focus deviation of the respective reference wavelengths is controlled within ± 0.05mm, and for a large wide-angle system, the diffuse spots or color halos in an imaging picture are effectively suppressed. FIG. 2 also includes an Astigmatic Field plot (Astigmatic Field plots) of the Field of the optical system 10, where the S curve represents sagittal Field curvature at 486nm and the T curve represents meridional Field curvature at 486 nm. As can be seen from the figure, the field curvature of the optical system 10 is small, the maximum field curvature is controlled within ± 0.05mm, for a large aperture system, the degree of curvature of an image plane is effectively suppressed, the sagittal field curvature and the meridional field curvature under each field tend to be consistent, and the astigmatism of each field is well controlled, so that it is known that the center to the edge of the field of the optical system 10 have clear imaging. Further, it is understood from the distortion map that the degree of distortion of the optical system 10 having a large aperture characteristic is also well controlled.

Second embodiment

Referring to fig. 3, in the second embodiment, the optical system 10 includes, in order from an object side to an image side along an optical axis 101, 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 aperture stop STO, 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 positive refractive power. The respective lens surface types of the optical system 10 are as follows:

the object-side surface S3 of the second lens element L2 is concave at the paraxial region 101, and the image-side surface S4 is concave at the paraxial region 101;

the object-side surface S7 of the fourth lens element L4 is convex at the paraxial region 101, and the image-side surface S8 is convex at the paraxial region 101;

the object-side surface S11 of the sixth lens element L6 is concave at the paraxial region 101, and the image-side surface S12 is concave at the paraxial region 101;

the object-side surface S15 of the eighth lens element L8 is convex at the paraxial region 101, and the image-side surface S16 is concave at the paraxial region 101.

Further, in the present embodiment, the image-side surface S10 of the fifth lens element L5 is cemented with the object-side surface S11 of the sixth lens element L6, and the aperture stop STO is located between the fourth lens element L4 and the fifth lens element L5, and the lens parameters of the optical system 10 are given in table 2, wherein the definitions of the names and parameters of the elements can be obtained in the first embodiment, which is not described herein again.

TABLE 2

As can be seen from the aberration diagrams in fig. 4, the longitudinal spherical aberration, curvature of field, astigmatism, and distortion of the optical system 10 having the wide-angle characteristic are all controlled well, and the optical system 10 of this embodiment can have 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 along the optical axis 101, 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 aperture stop STO, 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. The respective lens surface types of the optical system 10 are as follows:

the object-side surface S9 of the fifth lens element L5 is concave at the paraxial region 101, and the image-side surface S10 is convex at the paraxial region 101;

Further, in the present embodiment, the image-side surface S10 of the fifth lens L5 is cemented with the object-side surface S11 of the sixth lens L6, and the aperture stop STO is located between the fourth lens L4 and the fifth lens L5, and the lens parameters of the optical system 10 in the present embodiment are given in table 3, wherein the definitions of the names and parameters of the elements can be obtained in the first embodiment, which is not described herein again.

TABLE 3

As can be seen from the aberration diagrams in fig. 6, the longitudinal spherical aberration, curvature of field, astigmatism, and distortion of the optical system 10 having the wide-angle characteristic are all controlled well, and the optical system 10 of this embodiment can have good imaging quality.

Fourth embodiment

Referring to fig. 7, in the fourth embodiment, the optical system 10 includes, in order from the object side to the image side along the optical axis 101, 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 aperture stop STO, the fifth lens element L5 with negative 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 positive refractive power. The respective lens surface types of the optical system 10 are as follows:

the object-side surface S9 of the fifth lens element L5 is convex at the paraxial region 101, and the image-side surface S10 is concave at the paraxial region 101;

the object-side surface S11 of the sixth lens element L6 is convex at the paraxial region 101, and the image-side surface S12 is concave at the paraxial region 101;

the object-side surface S15 of the eighth lens element L8 is convex at the paraxial region 101, and the image-side surface S16 is convex at the paraxial region 101.

Further, in the present embodiment, the image-side surface S10 of the fifth lens L5 is cemented with the object-side surface S11 of the sixth lens L6, and the aperture stop STO is located between the fourth lens L4 and the fifth lens L5, and the lens parameters of the optical system 10 in the present embodiment are given in table 4, wherein the definitions of the names and parameters of the elements can be obtained in the first embodiment, which is not described herein again.

TABLE 4

As can be seen from the aberration diagrams in fig. 8, the longitudinal spherical aberration, curvature of field, astigmatism, and distortion of the optical system 10 having the wide-angle characteristic are all controlled well, and the optical system 10 of this embodiment can have 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 along the optical axis 101, 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 aperture stop STO, 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. The respective lens surface types of the optical system 10 are as follows:

Further, in the present embodiment, the image-side surface S10 of the fifth lens L5 is cemented with the object-side surface S11 of the sixth lens L6, and the aperture stop STO is located between the third lens L3 and the fourth lens L4, and the lens parameters of the optical system 10 in the present embodiment are given in table 5, wherein the definitions of the names and parameters of the elements can be obtained in the first embodiment, which is not described herein again.

TABLE 5

As can be seen from the aberration diagrams in fig. 10, the longitudinal spherical aberration, curvature of field, astigmatism, and distortion of the optical system 10 having the wide-angle characteristic are all controlled well, and the optical system 10 of this embodiment can have good imaging quality.

Referring to table 6, table 6 summarizes ratios of the relations in the first to fifth embodiments of the present application.

TABLE 6

The optical system 10 in the above embodiments can keep good imaging quality while compressing the overall length to achieve a compact design, and can also have a larger field of view range, compared to a general optical system.

Referring to fig. 11, an embodiment of the present application further provides a camera module 20, where the camera module 20 includes an optical system 10 and a photosensitive chip 210, and the photosensitive chip 210 is disposed on an image side of the optical system 10, and the photosensitive chip 210 and the optical system can be fixed by a bracket. The photosensitive chip 210 may be a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) sensor. Generally, the image forming surface S19 of the optical system 10 overlaps the photosensitive surface of the photosensitive chip 210 when assembled. By adopting the optical system 10, the camera module 20 can realize wide-angle characteristics, large aperture characteristics and a miniaturized design, and can meet the requirements of large-range shooting and high imaging quality.

Referring to fig. 12, some embodiments of the present application further provide an electronic device 30. 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 display screen, a circuit board, a middle frame, a rear cover, or the like. The electronic device 30 may be, but is not limited to, a mobile phone, a video phone, a smart phone, an e-book reader, a tablet computer, a PDA (Personal Digital Assistant), a vehicle-mounted camera such as a car recorder, a wearable device such as a smart watch and smart glasses, and the like. The camera module 20 can realize wide-angle characteristics, large aperture characteristics and miniaturization design, so that the electronic device 30 can meet the requirements of large-range shooting and high imaging quality, and can also realize portable design.

It is understood that in other embodiments, an automobile 40 may be disclosed, as shown in fig. 13, the automobile 40 may include a body 410 and the camera module 20 as described above, and the camera module 20 is disposed on the body 410 to obtain image information. It is understood that the automobile 40 having the camera module 20 has all the technical effects of the optical system 10. Namely, the automobile 40 can acquire the environmental information inside or around the automobile body 410, and meanwhile, shooting and clear imaging in a wide angle range can be realized, so that a better driving early warning is provided for the driving of a driver. Since the above technical effects have been described in detail in the embodiment of the optical system 10, they will not be described herein.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; the connection can be mechanical connection, electrical connection or communication; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

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

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

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

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

a fifth lens element with refractive power;

a sixth lens element with refractive power;

an eighth lens element with refractive power;

the optical system satisfies the relationship:

480deg≤(FOV×TTL)/Imgh≤560deg；

2. The optical system of claim 1, wherein the optical system satisfies the relationship:

2≤SD11/SAGs11≤3.3；

3. The optical system of claim 1, wherein the optical system satisfies the relationship:

0.6≤|f12/f|≤1.3；

4. The optical system of claim 1, wherein the optical system satisfies the relationship:

44deg/mm≤FOV/f≤50deg/mm；

f is the effective focal length of the optical system.

5. The optical system of claim 1, wherein the optical system satisfies the relationship:

2≤ImgH/SD82≤3；

6. The optical system of claim 1, wherein the optical system satisfies the relationship:

1.5≤f3/f≤5.5；

7. The optical system of claim 1, wherein the optical system satisfies the relationship:

220≤OD/f≤250；

8. The optical system of claim 1, wherein the optical system satisfies the relationship:

23≤TTL/CT2≤38.2；

CT2 is the thickness of the second lens on the optical axis.

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

10. An electronic device, comprising a fixing member and the camera module set according to claim 10, wherein the camera module set is disposed on the fixing member.