CN113820830B

CN113820830B - Optical system, image capturing module, electronic device and carrier

Info

Publication number: CN113820830B
Application number: CN202111181894.5A
Authority: CN
Inventors: 乐宇明; 赵迪; 兰宾利; 周芮; 王欢; 朱志鹏; 请求不公布姓名
Original assignee: Jiangxi Oufei Optics Co ltd
Current assignee: Jiangxi Oufei Optics Co ltd
Priority date: 2021-10-11
Filing date: 2021-10-11
Publication date: 2023-10-13
Anticipated expiration: 2041-10-11
Also published as: CN113820830A

Abstract

The invention relates to an optical system, an image capturing module, electronic equipment and a carrier. 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; a second lens element with negative refractive power; a third lens element with positive refractive power having convex object-side and image-side surfaces; a fourth lens element with negative refractive power having a concave image-side surface; a fifth lens element with positive refractive power having a convex image-side surface; a sixth lens element with refractive power having a concave image-side surface; the fourth lens is glued with the fifth lens, and the optical system meets the following conditions: f45/f is more than or equal to 3.2 and less than or equal to 6.2. The optical system has good imaging quality, and is beneficial to improving the driving safety performance when applied to the vehicle-mounted imaging lens.

Description

Optical system, image capturing module, electronic device and carrier

Technical Field

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

Background

With the development of the automobile industry, on-board systems such as ADAS (Advanced Driving Assistant System, advanced driving assistance system), DMS (Driver Monitor System, driver monitoring system) and the like are gradually developed and market demands are also gradually increasing. The industry generally requires that the vehicle-mounted system and the vehicle-mounted equipment cooperate to monitor and identify the state outside the driving cab, so that the driving environment change of the driver is comprehensively judged, safety early warning is provided, the change of the driving state of the driver is reminded, and prevention is performed in advance. Of course, the higher the imaging quality of the vehicle-mounted imaging lens is, the more favorable the driver to clearly acquire the environment outside the driving cab.

However, the imaging quality of the current vehicle-mounted camera lens is still to be improved, which is not beneficial to the improvement of driving safety performance.

Disclosure of Invention

Based on this, it is necessary to provide an optical system, an image capturing module, an electronic device and a carrier for the problem that the imaging quality of the previous vehicle-mounted imaging lens is still to be improved.

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;

a second lens element with negative refractive power;

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 negative refractive power having a concave image-side surface at a paraxial region;

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

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

and the optical system satisfies the following conditional expression:

3.2≤f45/f≤6.2；

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

In the optical system, the first lens has negative refractive power, so that light rays with a large viewing angle can enter the optical system, and the viewing angle of the optical system can be enlarged. The second lens has negative refractive power, can share the negative refractive power of the first lens, and avoids the excessively strong refractive power of the single lens, thereby being beneficial to reducing the sensitivity of an optical system and improving the molding yield of the first lens and the second lens. The third lens element with positive refractive power has a convex object-side surface and a convex image-side surface at a paraxial region, which is beneficial to balancing aberrations generated by the first lens element and the second lens element, and is beneficial to shortening the overall length of the optical system and realizing a compact design. The fourth lens element with negative refractive power has a concave image-side surface at a paraxial region thereof, which is favorable for correcting aberrations generated by the object-side lens elements. The fifth lens element with positive refractive power is advantageous in shortening the back focal length of the optical system, thereby further shortening the overall length of the optical system. The image side surface of the fifth lens is convex at the paraxial region, which is favorable for correcting astigmatism and effectively converging light rays on the imaging surface. The image side surface of the sixth lens is concave at the paraxial region, which is favorable for correcting aberration and improving the imaging quality of the optical system.

Meanwhile, the negative refractive power of the fourth lens element is matched with the positive refractive power of the fifth lens element, so as to facilitate mutual correction of aberration. When the above conditional expression is satisfied, the refractive power ratio of the fourth lens element and the fifth lens element in the optical system can be reasonably configured, which is favorable for suppressing the generation of astigmatism and correcting the edge aberration and chromatic aberration, thereby being favorable for improving the imaging quality of the optical system. Exceeding the upper limit of the above conditional expression, the fourth lens element and the fifth lens element have insufficient refractive power, which is unfavorable for correcting the edge aberration and chromatic aberration, thereby being unfavorable for improving the resolution performance of the optical system; below the lower limit of the above conditional expression, the refractive powers of the fourth lens element and the fifth lens element are too high, so that serious astigmatism is likely to occur, which is not beneficial to improving the imaging quality of the optical system.

In one embodiment, the fourth lens is cemented with the fifth lens. The fourth lens and the fifth lens are glued, so that chromatic aberration of the optical system is corrected, mutual correction of chromatic aberration of the fourth lens and the fifth lens is further facilitated, and imaging quality of the optical system is improved.

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

CT5-CT4 is less than or equal to 1.5mm and less than or equal to 1 mm. Wherein CT4 is the thickness of the fourth lens element on the optical axis, and CT5 is the thickness of the fifth lens element on the optical axis. When the above conditional expression is satisfied, the difference of the center thicknesses of the fourth lens and the fifth lens can be reasonably configured, which is favorable for reducing the risk of cracking of the cemented lens formed by the fourth lens and the fifth lens and reducing the total length of the optical system.

18mm≤f1*f2/f≤23mm；

wherein f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens. When the conditional expression is satisfied, the duty ratio of the product of the effective focal lengths of the first lens and the second lens in the optical system can be reasonably configured, so that the incidence of large-angle light rays to the optical system is facilitated, the view angle of the optical system is enlarged, the astigmatism and the chromatic aberration of the optical system are corrected, and the imaging quality of the optical system is improved. Exceeding the upper limit of the above condition, the refractive powers of the first lens element and the second lens element are insufficient, which is not beneficial to the incidence of the light beam with a large angle to the optical system, and is not beneficial to the expansion of the angle of view of the optical system; below the lower limit of the above condition, the refractive powers of the first lens element and the second lens element are too high, which is prone to generate serious astigmatism and chromatic aberration, and is unfavorable for high-resolution imaging characteristics.

2.5≤f456/f123≤4.5；

f456 is a combined focal length of the fourth lens, the fifth lens and the sixth lens, and f123 is a combined focal length of the first lens, the second lens and the third lens. When the conditional expression is satisfied, the ratio of the combined focal lengths of the fourth lens, the fifth lens and the sixth lens to the combined focal lengths of the first lens, the second lens and the third lens can be reasonably configured, so that the capability of reasonably configuring the front lens group formed by the first lens, the second lens and the third lens to collect light is facilitated, the light with a large angle view field is facilitated to be injected into the optical system, and the optical system has the wide-angle characteristic; meanwhile, the light height of the rear lens group, which is formed by the fourth lens, the fifth lens and the sixth lens, of the light rays emitted out of the optical system is favorable for reasonable configuration, so that the generation of advanced aberration of the optical system is restrained, and the outer diameter of a lens in the optical system is reduced; in addition, the curvature of field generated by the front lens group is also favorably corrected, so that the resolution of the optical system is improved.

2≤CT2/|SAGS3|≤4；

wherein, CT2 is the thickness of the second lens on the optical axis, and SAGS3 is the distance from the maximum effective caliber of the object side surface of the second lens to the intersection point of the object side surface of the second lens and the optical axis in the direction of the optical axis, i.e. the sagittal height of the object side surface of the second lens at the maximum effective caliber. When the condition is satisfied, the sagittal ratio of the center thickness of the second lens to the object side surface of the second lens at the maximum effective caliber can be reasonably configured, the situation that the lens manufacturing difficulty is increased due to overlarge center thickness or overlarge object side surface of the second lens is avoided, and therefore the forming yield of the second lens is improved, and the production cost is reduced. Below the lower limit of the above conditional expression, the object-side surface of the second lens is excessively curved, which results in increased processing difficulty of the second lens; meanwhile, the second lens is easy to generate serious edge aberration, which is unfavorable for improving the imaging quality of the optical system. Exceeding the upper limit of the above conditional expression, the center thickness of the second lens is excessively large, which is disadvantageous for weight reduction and miniaturization of the optical system.

TTL is more than or equal to 12mm and less than or equal to 14mm. The TTL is a distance between the object side surface of the first lens and the imaging surface of the optical system on the optical axis, that is, an optical total length of the optical system. When the above conditional expression is satisfied, the optical total length of the optical system can be reasonably configured, which is beneficial to the compact structure of the optical system and the miniaturization of the optical system.

-6mm*10 ^-6 /℃≤(CT4-CT5)*(α4-α5)≤-4mm*10 ^-6 /℃；

wherein, CT4 is the thickness of the fourth lens on the optical axis, CT5 is the thickness of the fifth lens on the optical axis, alpha 4 is the thermal expansion coefficient of the fourth lens at-30-70 ℃, and alpha 5 is the thermal expansion coefficient of the fifth lens at-30-70 ℃. When the above conditional expression is satisfied, the center thickness difference and the material difference of the fourth lens can be reasonably configured, the reasonable material collocation is favorable for reducing the influence of temperature on the optical system, so that the optical system can maintain good imaging quality under the high-temperature or low-temperature condition, and meanwhile, the center thickness difference and the material characteristic difference of the fourth lens and the fifth lens are favorable for reducing the risk of cracking of a glued lens formed by the fourth lens and the fifth lens, and the optical system still has better resolving power under the high-temperature or low-temperature condition.

0.5≤(CT3+D34)/f≤1；

wherein CT3 is the thickness of the third lens element on the optical axis, and D34 is the distance between the image side surface of the third lens element and the object side surface of the fourth lens element on the optical axis. By satisfying the upper limit of the conditional expression, the excessive center thickness of the third lens and the air space of the third lens and the fourth lens on the optical axis can be avoided, thereby being beneficial to realizing the miniaturization design of the optical system. The lower limit of the conditional expression is met, so that the center thickness of the third lens and the air space of the third lens and the fourth lens on the optical axis are not too small, correction of aberration of the optical system is facilitated, and imaging quality of the optical system is improved.

11≤SDS5/SAGS5≤14；

the SDS5 is the maximum effective aperture of the object side surface of the third lens, and the SAGS5 is the distance between the maximum effective aperture of the object side surface of the third lens and the intersection point of the object side surface of the third lens and the optical axis in the optical axis direction, that is, the sagittal height of the object side surface of the third lens at the maximum effective aperture. The lower limit of the condition is met, so that the object side surface type of the third lens is prevented from being excessively bent, the incidence of large-angle light rays to the optical system is facilitated, the angle of view of the optical system is further facilitated to be enlarged, the imaging quality of the optical system is improved, the processing difficulty of the third lens is also facilitated to be reduced, and the condition that the plating film is uneven due to the excessively bent object side surface type of the third lens is avoided; by satisfying the upper limit of the conditional expression, the object-side surface shape of the third lens can be prevented from being too gentle, and the risk of generating ghost images can be reduced.

An image capturing module includes a photosensitive element and the optical system according to any of the above embodiments, where the photosensitive element is disposed on an image side of the optical system. The optical system is adopted in the image capturing module, so that the image capturing module can have good imaging quality.

An electronic device comprises a shell and the image capturing module, wherein the image capturing module is arranged on the shell. The image capturing module is adopted in the electronic equipment, so that the electronic equipment can have good imaging quality.

A carrier comprises a mounting piece and the electronic equipment, wherein the electronic equipment is arranged on the mounting piece. By adopting the electronic equipment in the carrier, the electronic equipment has good imaging quality, and is beneficial to a driver to clearly acquire the environment outside the driving cab, so that the safety performance of the carrier is improved.

Drawings

Fig. 1 is a schematic structural view of an optical system in a first embodiment of the present application;

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

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

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

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

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

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

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

FIG. 9 is a schematic diagram of an image capturing module according to an embodiment of the present application;

FIG. 10 is a schematic diagram of an electronic device according to an embodiment of the application;

fig. 11 is a schematic structural diagram of a carrier according to an embodiment of the application.

Detailed Description

In order that the above objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the application, whereby the application is not limited to the specific embodiments disclosed below.

In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

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

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.

Referring to fig. 1, in some embodiments of the present application, the optical system 100 includes 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 in order from an object side to an image side along an optical axis 110. Specifically, the first lens element L1 comprises an object-side surface S1 and an image-side surface S2, the second lens element L2 comprises an object-side surface S3 and an image-side surface S4, the third lens element L3 comprises an object-side surface S5 and an image-side surface S6, the fourth lens element L4 comprises an object-side surface S7 and an image-side surface S8, the fifth lens element L5 comprises an object-side surface S9 and an image-side surface S10, and the sixth lens element L6 comprises an object-side surface S11 and an image-side surface S12. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 are coaxially disposed, and an axis common to the lenses in the optical system 100 is an optical axis 110 of the optical system 100.

The first lens element L1 with negative refractive power is beneficial to light entering the optical system 100 from a large viewing angle, thereby being beneficial to enlarging the viewing angle of the optical system 100. The second lens element L2 has negative refractive power, and is capable of sharing the negative refractive power of the first lens element L1, thereby avoiding excessive refractive power of a single lens element, and thus being beneficial to reducing the sensitivity of the optical system 100 and improving the molding yield of the first lens element L1 and the second lens element L2. The third lens element L3 with positive refractive power has a convex object-side surface S5 and a convex image-side surface S6 at a paraxial region 110, which is beneficial to balancing aberrations generated by the first lens element L1 and the second lens element L2, and shortening the overall length of the optical system 100 to achieve a compact design. The fourth lens element L4 with negative refractive power has a concave image-side surface S8 at a paraxial region 110, which is favorable for correcting aberrations generated by the object-side lens elements of the fourth lens element L4. The image-side surface S8 of the fourth lens element L4 is concave at the paraxial region 110. The fifth lens element L5 with positive refractive power advantageously shortens the back focal length of the optical system 100, thereby further shortening the overall length of the optical system 100. The image-side surface S10 of the fifth lens element L5 is convex at the paraxial region 110, which is beneficial to correcting astigmatism and converging light onto an image plane. The sixth lens element L6 with refractive power. The image-side surface S12 of the sixth lens element L6 is concave at the paraxial region 110, which is beneficial to correcting aberration and improving the imaging quality of the optical system 100. The negative refractive power of the fourth lens element L4 and the positive refractive power of the fifth lens element L5 cooperate to facilitate mutual aberration correction.

In some embodiments, the image side surface S8 of the fourth lens element L4 is attached to the object side surface S9 of the fifth lens element L5, for example, the fourth lens element L4 is glued to the fifth lens element L5, or the fourth lens element L4 is attached to the fifth lens element L5 by a fastening structure, which is beneficial to correcting the chromatic aberration of the optical system 100, and is also beneficial to mutually correcting the chromatic aberration of the fourth lens element L4 and the fifth lens element L5, thereby improving the imaging quality of the optical system 100.

In addition, in some embodiments, the optical system 100 is provided with a stop STO, which may be disposed between the third lens L3 and the fourth lens L4. In some embodiments, the optical system 100 further includes a filter L7 disposed on the image side of the sixth lens L6. The filter L7 may be an infrared cut filter, and is used for filtering out interference light, so as to prevent the interference light from reaching the imaging surface of the optical system 100 to affect normal imaging. The optical filter L7 may be an infrared band-pass filter, and the optical system 100 is also suitable for use in environments such as at night, and suitable for use in an infrared detection lens. In some embodiments, the optical system 100 is adapted for use with day and night confocal lenses. Of course, in other embodiments, the filter L7 may be a combination of an ir cut filter and a protective glass, where the protective glass is used to protect the photosensitive element at the imaging surface. Further, the optical system 100 further includes an image plane S15 located at the image side of the sixth lens L6, where the image plane S15 is an imaging plane of the optical system 100, and the incident light can be imaged on the image plane S15 after being adjusted by the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6.

In some embodiments, the object side and the image side of each lens of the optical system 100 are both aspheric. The adoption of the aspheric structure can improve the flexibility of lens design, effectively correct spherical aberration and improve imaging quality. In other embodiments, the object side and image side of each lens of the optical system 100 may be spherical. It should be noted that the above embodiments are merely examples of some embodiments of the present application, and in some embodiments, the surfaces of the lenses in the optical system 100 may be aspherical or any combination of spherical surfaces. Further, in some embodiments, the object-side surfaces and the image-side surfaces of the first lens element L1 and the third lens element L3 are spherical, and the object-side surfaces and the image-side surfaces of the second lens element L2, the fourth lens element L4, the fifth lens element L5 and the sixth lens element L6 are aspheric, so that the optical system 100 can obtain more control variables, and the aberration can be effectively corrected without increasing the number of lenses, thereby being beneficial to shortening the overall length of the optical system 100.

In some embodiments, the materials of the lenses in the optical system 100 may be glass or plastic. The plastic lens can reduce the weight of the optical system 100 and the production cost, and the small size of the optical system 100 is matched to realize the light and thin design of the optical system 100. The lens made of glass material provides the optical system 100 with excellent optical performance and high temperature resistance. It should be noted that the materials of the lenses in the optical system 100 may be any combination of glass and plastic, and are not necessarily all glass or all plastic. Further, in some embodiments, the materials of the first lens L1, the third lens L3 and the sixth lens L6 are glass, the materials of the second lens L2, the fourth lens L4 and the fifth lens L5 are plastic, and reasonable material matching is beneficial to reducing the offset of the imaging surface in the high-low temperature environment, so that the optical system 100 can have good resolving power in the high-low temperature environment.

It should be noted that the first lens L1 does not mean that there is only one lens, and in some embodiments, there may be two or more lenses in the first lens L1, where the two or more lenses can form a cemented lens, a surface of the cemented lens closest to the object side may be referred to as an object side surface S1, and a surface closest to the image side may be referred to as an image side surface S2. Alternatively, the first lens L1 does not have a cemented lens, but the distance between the lenses is relatively constant, and 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 be greater than or equal to two, and any adjacent lenses may form a cemented lens therebetween, or may be a non-cemented lens.

Further, in some embodiments, the optical system 100 satisfies the conditional expression: f45/f is more than or equal to 3.2 and less than or equal to 6.2; wherein f45 is a combined focal length of the fourth lens element L4 and the fifth lens element L5, and f is an effective focal length of the optical system 100. Specifically, f45/f may be: 3.427, 3.652, 3.951, 4.402, 4.655, 5.025, 5.831, 5.944, 5.982 or 6.013. When the above conditional expression is satisfied, the refractive power ratio of the fourth lens element L4 and the fifth lens element L5 in the optical system 100 can be reasonably configured, which is beneficial to suppressing the generation of astigmatism and correcting the edge aberration and chromatic aberration, thereby improving the imaging quality of the optical system 100. Exceeding the upper limit of the above conditional expression, the fourth lens element L4 and the fifth lens element L5 have insufficient refractive power, which is disadvantageous for correcting the edge aberration and chromatic aberration, thereby being disadvantageous for improving the resolution performance of the optical system 100; below the lower limit of the above condition, the refractive powers of the fourth lens element L4 and the fifth lens element L5 are too high, which is prone to generate serious astigmatism, and is not beneficial to improving the imaging quality of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: CT5-CT4 is less than or equal to 1.5mm and less than or equal to 1 mm. Wherein, CT4 is the thickness of the fourth lens element L4 on the optical axis 110, and CT5 is the thickness of the fifth lens element L5 on the optical axis 110. Specifically, CT5-CT4 may be: 1.015, 1.017, 1.020, 1.023, 1.033, 1.045, 1.057, 1.111, 1.208 or 1.286. When the above conditional expression is satisfied, the difference in center thickness between the fourth lens L4 and the fifth lens L5 can be reasonably configured, which is advantageous for reducing the risk of cracking the cemented lens formed by the fourth lens L4 and the fifth lens L5, and also for reducing the total length of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: f1 is less than or equal to 18mm, f2/f is less than or equal to 23mm; wherein f1 is the effective focal length of the first lens L1, and f2 is the effective focal length of the second lens L2. Specifically, f1 x f2/f may be: 18.681, 18.722, 18.789, 18.809, 19.325, 21.024, 22.603, 22.617, 22.703 or 22.772, in mm. When the above conditional expression is satisfied, the duty ratio of the product of the effective focal lengths of the first lens L1 and the second lens L2 in the optical system 100 can be reasonably configured, which is beneficial to the incidence of the light beam with a large angle into the optical system 100, thereby enlarging the field angle of the optical system 100, and simultaneously, is beneficial to the correction of astigmatism and chromatic aberration of the optical system 100, and improving the imaging quality of the optical system 100. Exceeding the upper limit of the above conditional expression, the refractive powers of the first lens element L1 and the second lens element L2 are insufficient, which is not beneficial to the large-angle light incident on the optical system 100 and to the expansion of the field angle range of the optical system 100; below the lower limit of the above condition, the refractive powers of the first lens element L1 and the second lens element L2 are too high, which is prone to generate serious astigmatism and chromatic aberration, and is not beneficial to high-resolution imaging characteristics.

In some embodiments, the optical system 100 satisfies the conditional expression: f456/f123 is more than or equal to 2.5 and less than or equal to 4.5; f456 is a combined focal length of the fourth lens L4, the fifth lens L5 and the sixth lens L6, and f123 is a combined focal length of the first lens L1, the second lens L2 and the third lens L3. Specifically, f456/f123 may be: 2.972, 3.022, 3.055, 3.111, 3.257, 3.514, 3.647, 3.810, 3.996 or 4.113. When the above conditional expression is satisfied, the ratio of the combined focal lengths of the fourth lens L4, the fifth lens L5 and the sixth lens L6 to the combined focal lengths of the first lens L1, the second lens L2 and the third lens L3 can be reasonably configured, which is favorable for reasonably configuring the capability of converging light rays of the front lens group consisting of the first lens L1, the second lens L2 and the third lens L3, thereby being favorable for injecting light rays with a large angle field into the optical system 100, so that the optical system 100 has wide-angle characteristics; meanwhile, the height of the light rays emitted from the optical system by the rear lens group consisting of the fourth lens L4, the fifth lens L5 and the sixth lens L6 is favorable for reasonable configuration, so that the generation of advanced aberration of the optical system 100 is inhibited and the outer diameter of lenses in the optical system 100 is reduced; in addition, the curvature of field generated by the front lens group is also advantageously corrected, thereby improving the resolution of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: CT2/|SAGS3| is more than or equal to 2 and less than or equal to 4; wherein, CT2 is the thickness of the second lens element L2 on the optical axis 110, and sag 3 is the distance from the maximum effective diameter of the object-side surface S3 of the second lens element L2 to the intersection point of the object-side surface S1 of the second lens element L2 and the optical axis 110 in the direction of the optical axis 110. Specifically, CT2/|sags3| may be: 2.620, 2.688, 2.725, 2.826, 3.105, 3.384, 3.504, 3.511, 3.515 or 3.519. When the above conditional expression is satisfied, the sagittal ratio of the center thickness of the second lens L2 to the object side surface S3 of the second lens L2 at the maximum effective caliber can be reasonably configured, so that the situation that the lens manufacturing difficulty is increased due to the overlarge center thickness of the second lens L2 or the overlarge object side surface S3 is avoided, thereby being beneficial to improving the molding yield of the second lens L2 and reducing the production cost. Below the lower limit of the above condition, the object side surface S3 of the second lens element L2 is excessively curved, resulting in increased difficulty in processing the second lens element L2; meanwhile, the second lens L2 is prone to generate serious edge aberration, which is unfavorable for improving the imaging quality of the optical system 100. Exceeding the upper limit of the above conditional expression, the center thickness of the second lens L2 is excessively large, which is disadvantageous in light weight and miniaturization of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: TTL is more than or equal to 12mm and less than or equal to 14mm. The TTL is a distance from the object side surface S1 of the first lens element L1 to the imaging surface of the optical system 100 on the optical axis 110, i.e. an optical total length of the optical system 100. Specifically, the TTL may be: 12.496, 12.497, 12.499, 12.500, 12.610, 12.744, 13.028, 13.225, 13.501 or 13.690 in mm. When the above conditional expression is satisfied, the optical total length of the optical system 100 can be reasonably configured, which is beneficial to the compact structure of the optical system 100 and the miniaturization of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: -6mm x 10 ^-6 /℃≤(CT4-CT5)*(α4-α5)≤-4mm*10 ^-6 a/DEG C; wherein, CT4 is the thickness of the fourth lens L4 on the optical axis 110, CT5 is the thickness of the fifth lens L5 on the optical axis 110, alpha 4 is the thermal expansion coefficient of the fourth lens L4 at-30-70 ℃, and alpha 5 is the thermal expansion coefficient of the fifth lens L5 at-30-70 ℃. Specifically, (CT 4-CT 5) × (α4- α5) can be: -5.144, -5.001, -4.555, -4.226, -4.155, -4.101, -4.094, -4.074, -4.60 or-4.058, in mm 10 ^-6 and/C. When the above conditional expression is satisfied, the center thickness difference and the material difference of the fourth lens L4 can be reasonably configured, the reasonable material collocation is favorable for reducing the influence of temperature on the optical system 100, so that the optical system 100 can maintain good imaging quality under high temperature or low temperature conditions, and simultaneously, the center thickness difference and the material characteristic difference of the fourth lens L4 and the fifth lens L5 are favorable for reducing the risk of cracking of the bonding lens formed by the fourth lens L4 and the fifth lens L5, so that the optical system 100 still has higher imaging quality under high temperature or low temperature conditions Good resolving power.

In some embodiments, the optical system 100 satisfies the conditional expression: (CT 3 +D34)/f is more than or equal to 0.5 and less than or equal to 1; wherein, CT3 is the thickness of the third lens element L3 on the optical axis 110, and D34 is the distance between the image side surface S6 of the third lens element L3 and the object side surface S7 of the fourth lens element L4 on the optical axis 110. Specifically, (ct3+d34)/f may be: 0.954, 0.956, 0.957, 0.959, 0.961, 0.963, 0.965, 0.967, 0.968, or 0.969. By satisfying the upper limit of the above conditional expression, the center thickness of the third lens L3 and the air space between the third lens L3 and the fourth lens L4 on the optical axis 110 can be prevented from being excessively large, which is advantageous for realizing the miniaturized design of the optical system 100. By satisfying the lower limit of the above conditional expression, the center thickness of the third lens L3 and the air space between the third lens L3 and the fourth lens L4 on the optical axis 110 are not too small, which is beneficial to correcting the aberration of the optical system 100 and improving the imaging quality of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: SDS5/SAGS5 is less than or equal to 11 and less than or equal to 14; wherein SDS5 is the maximum effective aperture of the object side surface S5 of the third lens element L3, and sag 5 is the distance between the position of the maximum effective aperture of the object side surface S5 of the third lens element L3 and the intersection point of the object side surface S5 of the third lens element L3 and the optical axis 110 in the direction of the optical axis 110. Specifically, SDS5/SAGS5 may be: 11.236, 11.441, 11.685, 11.879, 12.102, 12.552, 12.961, 13.047, 13.411 or 13.602. By meeting the lower limit of the conditional expression, the situation that the object side surface S5 of the third lens L3 is excessively bent is avoided, so that large-angle light is favorably incident to the optical system 100, the angle of view of the optical system 100 is favorably enlarged, the imaging quality of the optical system 100 is favorably improved, the processing difficulty of the third lens L3 is favorably reduced, and the situation that the plating film is uneven due to the excessively bent object side surface S5 of the third lens L3 is avoided; by satisfying the upper limit of the above conditional expression, the object side surface S5 of the third lens element L3 can be prevented from being excessively gentle, which is advantageous for reducing the risk of generating ghost images.

The reference wavelength for the above effective focal length and combined focal length values are both 550nm.

From the above description of the embodiments, more particular embodiments and figures are set forth below in detail.

First embodiment

Referring to fig. 1 and 2, fig. 1 is a schematic structural diagram of an optical system 100 in a first embodiment, wherein the optical system 100 includes, in order from an object side to an image side, a first lens element L1 with negative refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a stop STO, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, and a sixth lens element L6 with negative refractive power. Fig. 2 is a graph of longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the first embodiment, from left to right, where the reference wavelength of the astigmatism graph and the distortion graph is 550nm, and other embodiments are the same.

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 of the second lens element L2 is concave at the paraxial region 110, and the image side surface S4 is convex at the paraxial region 110;

the object side surface S5 of the third lens element L3 is convex, and the image side surface S6 is convex;

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

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

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

The object side surfaces and the image side surfaces of the first lens element L1 and the third lens element L3 are spherical, and the object side surfaces and the image side surfaces of the second lens element L2, the fourth lens element L4, the fifth lens element L5 and the sixth lens element L6 are aspheric.

The materials of the first lens L1, the third lens L3 and the sixth lens L6 are glass, and the materials of the second lens L2, the fourth lens L4 and the fifth lens L5 are plastic.

Further, the optical system 100 satisfies the conditional expression: f45/f= 4.402; wherein f45 is a combined focal length of the fourth lens element L4 and the fifth lens element L5, and f is an effective focal length of the optical system 100. When the above conditional expression is satisfied, the refractive power ratio of the fourth lens element L4 and the fifth lens element L5 in the optical system 100 can be reasonably configured, which is beneficial to suppressing the generation of astigmatism and correcting the edge aberration and chromatic aberration, thereby improving the imaging quality of the optical system 100.

The optical system 100 satisfies the conditional expression: CT5-CT4 = 1.286mm. Wherein, CT4 is the thickness of the fourth lens element L4 on the optical axis 110, and CT5 is the thickness of the fifth lens element L5 on the optical axis 110. When the above conditional expression is satisfied, the difference in center thickness between the fourth lens L4 and the fifth lens L5 can be reasonably configured, which is advantageous for reducing the risk of cracking the cemented lens formed by the fourth lens L4 and the fifth lens L5, and also for reducing the total length of the optical system 100.

The optical system 100 satisfies the conditional expression: f1×f2/f= 18.681mm; wherein f1 is the effective focal length of the first lens L1, and f2 is the effective focal length of the second lens L2. When the above conditional expression is satisfied, the duty ratio of the product of the effective focal lengths of the first lens L1 and the second lens L2 in the optical system 100 can be reasonably configured, which is beneficial to the incidence of the light beam with a large angle into the optical system 100, thereby enlarging the field angle of the optical system 100, and simultaneously, is beneficial to the correction of astigmatism and chromatic aberration of the optical system 100, and improving the imaging quality of the optical system 100.

The optical system 100 satisfies the conditional expression: f456/f123= 3.111; f456 is a combined focal length of the fourth lens L4, the fifth lens L5 and the sixth lens L6, and f123 is a combined focal length of the first lens L1, the second lens L2 and the third lens L3. When the above conditional expression is satisfied, the ratio of the combined focal lengths of the fourth lens L4, the fifth lens L5 and the sixth lens L6 to the combined focal lengths of the first lens L1, the second lens L2 and the third lens L3 can be reasonably configured, which is favorable for reasonably configuring the capability of converging light rays of the front lens group consisting of the first lens L1, the second lens L2 and the third lens L3, thereby being favorable for injecting light rays with a large angle field into the optical system 100, so that the optical system 100 has wide-angle characteristics; meanwhile, the height of the light rays emitted from the optical system 100 by the rear lens group consisting of the fourth lens L4, the fifth lens L5 and the sixth lens L6 is favorable for reasonable configuration, so that the generation of advanced aberration of the optical system 100 is inhibited and the outer diameter of lenses in the optical system 100 is reduced; in addition, the curvature of field generated by the front lens group is also advantageously corrected, thereby improving the resolution of the optical system 100.

The optical system 100 satisfies the conditional expression: CT 2/|sags3|= 2.826; wherein, CT2 is the thickness of the second lens element L2 on the optical axis 110, and sag 3 is the distance from the maximum effective diameter of the object-side surface S3 of the second lens element L2 to the intersection point of the object-side surface S1 of the second lens element L2 and the optical axis 110 in the direction of the optical axis 110. When the above conditional expression is satisfied, the sagittal ratio of the center thickness of the second lens L2 to the object side surface S3 of the second lens L2 at the maximum effective caliber can be reasonably configured, so that the situation that the lens manufacturing difficulty is increased due to the overlarge center thickness of the second lens L2 or the overlarge object side surface S3 is avoided, thereby being beneficial to improving the molding yield of the second lens L2 and reducing the production cost.

The optical system 100 satisfies the conditional expression: ttl=12.500 mm. The TTL is a distance from the object side surface S1 of the first lens element L1 to the imaging surface of the optical system 100 on the optical axis 110, i.e. an optical total length of the optical system 100. When the above conditional expression is satisfied, the optical total length of the optical system 100 can be reasonably configured, which is beneficial to the compact structure of the optical system 100 and the miniaturization of the optical system 100.

The optical system 100 satisfies the conditional expression: (CT 4-CT 5) = -5.144mm x 10 ^-6 a/DEG C; wherein, CT4 is the thickness of the fourth lens L4 on the optical axis 110, CT5 is the thickness of the fifth lens L5 on the optical axis 110, alpha 4 is the thermal expansion coefficient of the fourth lens L4 at-30-70 ℃, and alpha 5 is the thermal expansion coefficient of the fifth lens L5 at-30-70 ℃. When the above conditional expression is satisfied, the center thickness difference and the material difference of the fourth lens L4 can be reasonably configured, and the reasonable material collocation is favorable for reducing the influence of temperature on the optical system 100, so that the optical system 100 can maintain good imaging quality under the high temperature or low temperature condition, and simultaneously, the center thickness difference and the material characteristic difference of the fourth lens L4 and the fifth lens L5 are favorable for reducing the risk of cracking of the bonding lens formed by the fourth lens L4 and the fifth lens L5, so that the optical system 100 still has better resolving power under the high temperature or low temperature condition.

The optical system 100 satisfies the conditional expression: (CT 3+ D34)/f=0.954; wherein, CT3 is the thickness of the third lens element L3 on the optical axis 110, and D34 is the distance between the image side surface S6 of the third lens element L3 and the object side surface S7 of the fourth lens element L4 on the optical axis 110. When the above conditional expression is satisfied, the center thickness of the third lens L3 and the air space between the third lens L3 and the fourth lens L4 on the optical axis 110 can be avoided from being too large, thereby being beneficial to realizing the miniaturization design of the optical system 100; meanwhile, the center thickness of the third lens L3 and the air space between the third lens L3 and the fourth lens L4 on the optical axis 110 can be not too small, which is beneficial to correcting the aberration of the optical system 100 and improving the imaging quality of the optical system 100.

The optical system 100 satisfies the conditional expression: SDS 5/sags5= 11.236; wherein SDS5 is the maximum effective aperture of the object side surface S5 of the third lens element L3, and sag 5 is the distance between the position of the maximum effective aperture of the object side surface S5 of the third lens element L3 and the intersection point of the object side surface S5 of the third lens element L3 and the optical axis 110 in the direction of the optical axis 110. When the above conditional expression is satisfied, the object side surface S5 of the third lens element L3 is prevented from being excessively curved, so that a large-angle light beam is facilitated to be incident into the optical system 100, the viewing angle of the optical system 100 is further facilitated to be enlarged, the imaging quality of the optical system 100 is improved, the processing difficulty of the third lens element L3 is also facilitated to be reduced, and the uneven plating caused by the excessively curved object side surface S5 of the third lens element L3 is avoided; in addition, the object side surface S5 of the third lens element L3 can be prevented from being excessively gentle, which is advantageous in reducing the risk of generating ghost images.

In addition, various parameters of the optical system 100 are given in table 1. The image plane S15 in table 1 can be understood as the imaging plane of the optical system 100. The elements from the object plane (not shown) to the image plane S15 are arranged in the order of the elements from top to bottom in table 1. The radius Y in table 1 is the radius of curvature of the object or image side of the corresponding surface number at the optical axis 110. The surface numbers S1 and S2 are the object side surface S1 and the image side surface S2 of the first lens element L1, respectively, i.e., the surface with the smaller surface number is the object side surface and the surface with the larger surface number is the image side surface in the same lens element. The first value in the "thickness" parameter row of the first lens element L1 is the thickness of the lens element on the optical axis 110, and the second value is the distance from the image side surface of the lens element to the rear surface of the image side direction on the optical axis 110.

Note that in this embodiment and the following embodiments, the optical system 100 may not be provided with the optical filter L7, but the distance from the image side surface S12 to the image surface S15 of the sixth lens L6 remains unchanged.

In the first embodiment, the effective focal length f=2.49 mm, the f-number fno=2.1, and the maximum field angle fov=180° of the optical system 100. In the first embodiment and the other embodiments, the maximum field angle of the optical system 100 satisfies 180 ° or less and 184 ° or less, and it is known that the optical system 100 has a wide angle characteristic, and is capable of obtaining a scene with a sufficiently large object space range, so that when the optical system 100 is applied to the vehicle-mounted device, it is beneficial for a driver to grasp more environment information, and improves the driving safety performance.

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

The reference wavelength for the focal length of each lens was 550nm, and the reference wavelength for the refractive index and Abbe number was 587.56nm (d-wavelength), as was the case with other embodiments.

TABLE 1

Further, the aspherical coefficients of the image side or object side of each lens of the optical system 100 are given in table 2. The surface numbers S3 and S4 denote the object side surfaces S3 and S4 of the second lens element L2, respectively, the surface number S7 denotes the object side surface S7 of the fourth lens element L4, and the surface numbers S9 to S12 denote the image side surfaces or the object side surfaces S9 to S12, respectively. And K-a20 from top to bottom respectively represent types of aspherical coefficients, where K represents a conic coefficient, A4 represents four times an aspherical coefficient, A6 represents six times an aspherical coefficient, A8 represents eight times an aspherical coefficient, and so on. In addition, the aspherical coefficient formula is as follows:

where Z is the distance from the corresponding point on the aspheric surface to the plane tangential to the surface vertex, r is the distance from the corresponding point on the aspheric surface to the optical axis 110, c is the curvature of the aspheric vertex, k is the conic coefficient, ai is the coefficient corresponding to the i-th higher term in the aspheric surface formula.

TABLE 2

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In addition, fig. 2 includes a longitudinal spherical aberration diagram (Longitudinal Spherical Aberration) of the optical system 100, which shows the deviation of the focal point of light rays of different wavelengths after passing through the lens. The ordinate of the longitudinal spherical aberration diagram represents the normalized pupil coordinates (Normalized Pupil Coordinator) from the pupil center to the pupil edge, and the abscissa represents the distance (in mm) from the imaging plane to the intersection of the light ray with the optical axis 110. As can be seen from the longitudinal spherical aberration diagram, the degree of focus deviation of the light beams with the respective wavelengths in the first embodiment tends to be uniform, and the diffuse spots or the halos in the imaging picture are effectively suppressed. Fig. 2 also includes an astigmatic field plot (ASTIGMATIC FIELD CURVES) of the optical system 100, where the S-curve represents the sagittal field curvature at 550nm and the T-curve represents the meridional field curvature at 550 nm. As can be seen from the figure, the field curvature of the optical system 100 is small, the field curvature and astigmatism of each field of view are well corrected, and the center and the edge of the field of view have clear imaging. Fig. 2 also includes a DISTORTION map (DISTORTION) of the optical system 100, in which it is seen that the DISTORTION of the image caused by the main beam is small and the imaging quality of the system is good.

Second embodiment

Referring to fig. 3 and 4, fig. 3 is a schematic structural diagram of an optical system 100 in a second embodiment, wherein the optical system 100 includes, in order from an object side to an image side, a first lens element L1 with negative refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a stop STO, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, and a sixth lens element L6 with positive refractive power. Fig. 4 is a graph showing longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the second embodiment in order from left to right.

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

TABLE 3 Table 3

Further, the aspheric coefficients of the image side or the object side of each lens of the optical system 100 are given in table 4, and the definition of each parameter can be obtained from the first embodiment, which is not described herein.

TABLE 4 Table 4

From the above provided parameter information, the following data can be deduced:

f45/f	6.013	TTL(mm)	12.496
				CT5-CT4(mm)	1.015	(CT4-CT5)(α4-α5)(mm10-6/℃)	-4.058
f1*f2/f(mm)	22.603	(CT3+D34)/f	0.969
				f456/f123	3.647	SDS5/SAGS5	13.602
CT2/\|SAGS3\|	3.519

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

Third embodiment

Referring to fig. 5 and 6, fig. 5 is a schematic structural diagram of an optical system 100 in a third embodiment, wherein the optical system 100 includes, in order from an object side to an image side, a first lens element L1 with negative refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a stop STO, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, and a sixth lens element L6 with negative refractive power. Fig. 6 is a graph showing longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the third embodiment in order from left to right.

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

TABLE 5

Further, the aspheric coefficients of the image side or the object side of each lens of the optical system 100 are given in table 6, and the definition of each parameter can be obtained from the first embodiment, which is not described herein.

TABLE 6

Face number	S3	S4	S7	S9
					K	1.190E+00	-4.334E+00	0.000E+00	-2.085E-01
A4	2.181E-02	8.833E-03	4.872E-04	9.379E-03
					A6	5.268E-04	6.517E-03	1.183E-03	-2.809E-04
A8	7.828E-04	-2.643E-04	-3.876E-03	-4.456E-06
					A10	-5.675E-05	5.296E-04	9.772E-04	5.522E-04
A12	4.865E-05	-2.094E-05	0.000E+00	0.000E+00
					A14	0.000E+00	0.000E+00	0.000E+00	0.000E+00
A16	0.000E+00	0.000E+00	0.000E+00	0.000E+00
					A18	0.000E+00	0.000E+00	0.000E+00	0.000E+00
A20	0.000E+00	0.000E+00	0.000E+00	0.000E+00
					Face number	S10	S11	S12
K	-2.085E-01	0.000E+00	-4.708E+00
					A4	8.894E-03	-6.943E-02	-5.993E-02
A6	-2.809E-04	5.372E-03	7.326E-03
					A8	-4.456E-05	-7.642E-03	-7.774E-03
A10	5.552E-04	9.671E-04	2.589E-04
					A12	0.000E+00	-2.539E-05	-4.383E-06
A14	0.000E+00	0.000E+00	0.000E+00
					A16	0.000E+00	0.000E+00	0.000E+00
A18	0.000E+00	0.000E+00	0.000E+00
					A20	0.000E+00	0.000E+00	0.000E+00

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

f45/f	3.427	TTL(mm)	13.690
				CT5-CT4(mm)	1.057	(CT4-CT5)(α4-α5)(mm10-6/℃)	-4.226
f1*f2/f(mm)	18.809	(CT3+D34)/f	0.965
				f456/f123	2.972	SDS5/SAGS5	11.879
CT2/\|SAGS3\|	2.620

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

Fourth embodiment

Referring to fig. 7 and 8, fig. 7 is a schematic structural diagram of an optical system 100 in a fourth embodiment, wherein the optical system 100 includes, in order from an object side to an image side, a first lens element L1 with negative refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a stop STO, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, and a sixth lens element L6 with negative refractive power. Fig. 8 is a graph showing longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the fourth embodiment in order from left to right.

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

TABLE 7

Further, the aspheric coefficients of the image side or the object side of each lens in the optical system 100 are given in table 8, and the definition of each parameter can be obtained from the first embodiment, which is not described herein.

TABLE 8

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f45/f	5.831	TTL(mm)	12.500
				CT5-CT4(mm)	1.023	(CT4-CT5)(α4-α5)(mm10-6/℃)	-4.094
f1*f2/f(mm)	22.772	(CT3+D34)/f	0.969
				f456/f123	4.113	SDS5/SAGS5	12.961
CT2/\|SAGS3\|	3.504

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

Referring to fig. 9, in some embodiments, the optical system 100 may be assembled with the photosensitive element 210 to form the image capturing module 200. At this time, the photosensitive surface of the photosensitive element 210 can be regarded as the image surface S15 of the optical system 100. The image capturing module 200 may further be provided with an optical filter L7, where the optical filter L7 is disposed between the image side surface S12 and the image plane S15 of the sixth lens element L6. Specifically, the photosensitive element 210 may be a charge coupled element (Charge Coupled Device, CCD) or a complementary metal oxide semiconductor device (Complementary Metal-Oxide Semiconductor Sensor, CMOS Sensor). The optical system 100 is adopted in the image capturing module 200, so that the image capturing module 200 can have good imaging quality, and meanwhile, the image capturing module 200 has wide-angle characteristics and can meet the requirement of miniaturization design.

Referring to fig. 9 and 10, in some embodiments, the image capturing module 200 can be applied to an electronic device 300, which includes a housing 310, and the image capturing module 200 is disposed on the housing 310. Specifically, the electronic device 300 may be, but is not limited to, a portable telephone, a video phone, a smart phone, an electronic book reader, a vehicle-mounted image pickup device such as a car recorder, or a wearable device such as a smart watch. When the electronic device 300 is a smart phone, the housing 310 may be a middle frame of the electronic device 300. Of course, in some embodiments, the electronic apparatus 300 may also be an in-vehicle image pickup apparatus, an aircraft image pickup apparatus, a monitoring image pickup apparatus, or the like.

For example, in one embodiment, the electronic device 300 is a drone camera, and the image capturing module 200 is disposed within a housing 310 of the drone camera. The electronic device 300 can be rotated relative to the unmanned aerial vehicle housing, thereby adjusting the photographing angle. The electronic device 300 may be electrically connected to a control circuit in the unmanned aerial vehicle, and transmit the obtained image information to the user in real time by means of wireless signal transmission.

The above-mentioned image capturing module 200 is adopted in the electronic equipment 300, so that the electronic equipment 300 can have good imaging quality, can also have wide-angle characteristics and can meet the requirements of miniaturized design, and can clearly acquire a large range of environmental scenes when being applied to vehicle-mounted equipment, thereby being beneficial to drivers to grasp environmental changes and improving driving safety performance.

Referring to fig. 11, some embodiments of the present application also provide a carrier 400. The carrier 400 includes a mounting member 410 and the electronic device 300, and the electronic device 300 is disposed on the mounting member 410. The carrier can be a land running carrier such as an automobile, a train and the like, a flying carrier such as an unmanned plane and the like, or other common carriers capable of carrying people or objects. When the carrier 400 is an automobile, the mount 410 for disposing the electronic device 300 may be an intake grill, a rear trunk, a rear view mirror, or the like. By adopting the electronic device 30, the shooting function of the carrier 40 is improved, the shooting range can be enlarged, and meanwhile, clear images can be provided, so that the driving safety performance is improved.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.

Claims

1. An optical system, characterized in that the number of lenses with refractive power in the optical system is six, and the optical system sequentially comprises, from an object side to an image side along an optical axis:

a first lens element with negative refractive power;

a second lens element with negative refractive power;

and the optical system satisfies the following conditional expression:

3.2≤f45/f≤6.2；

11≤SDS5/SAGS5≤14；

wherein f45 is a combined focal length of the fourth lens element and the fifth lens element, f is an effective focal length of the optical system, SDS5 is an object-side surface maximum effective aperture of the third lens element, and sag 5 is a distance between an object-side surface maximum effective aperture of the third lens element and an intersection point of the object-side surface of the third lens element and the optical axis in the optical axis direction.

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

18mm≤f1*f2/f≤23mm；

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

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

2.5≤f456/f123≤4.5；

f456 is a combined focal length of the fourth lens, the fifth lens and the sixth lens, and f123 is a combined focal length of the first lens, the second lens and the third lens.

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

2≤CT2/|SAGS3|≤4；

wherein CT2 is the thickness of the second lens on the optical axis, SAGS3 is the distance from the position of the maximum effective caliber of the object side surface of the second lens to the intersection point of the object side surface of the second lens and the optical axis on the optical axis direction.

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

-6mm*10 ^-6 /℃≤（CT4-CT5）*（α4-α5）≤-4mm*10 ^-6 /℃；

wherein, CT4 is the thickness of the fourth lens on the optical axis, CT5 is the thickness of the fifth lens on the optical axis, alpha 4 is the thermal expansion coefficient of the fourth lens at-30-70 ℃, and alpha 5 is the thermal expansion coefficient of the fifth lens at-30-70 ℃.

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

0.5≤（CT3+D34）/f≤1；

Wherein CT3 is the thickness of the third lens element on the optical axis, and D34 is the distance between the image side surface of the third lens element and the object side surface of the fourth lens element on the optical axis.

7. The optical system of claim 1, wherein the object side and the image side of the first lens element and the third lens element are spherical, and the object side and the image side of the second lens element, the fourth lens element, the fifth lens element and the sixth lens element are aspheric.

8. An image capturing module comprising a photosensitive element and the optical system of any one of claims 1-7, wherein the photosensitive element is disposed on an image side of the optical system.

9. An electronic device, comprising a housing and the image capturing module of claim 8, wherein the image capturing module is disposed on the housing.

10. A carrier comprising a mounting member and the electronic device of claim 9, the electronic device being disposed on the mounting member.