CN113777752A

CN113777752A - Optical system, image capturing module and electronic equipment

Info

Publication number: CN113777752A
Application number: CN202111063916.8A
Authority: CN
Inventors: 乐宇明; 兰宾利; 赵迪
Original assignee: Tianjin OFilm Opto Electronics Co Ltd
Current assignee: Jiangxi Oufei Optics Co ltd
Priority date: 2021-09-10
Filing date: 2021-09-10
Publication date: 2021-12-10
Anticipated expiration: 2041-09-10
Also published as: CN113777752B

Abstract

The invention discloses an optical system, an image capturing module and electronic equipment, wherein the optical system comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a fifth lens, wherein the first lens, the second lens and the third lens are sequentially arranged from an object side to an image side along an optical axis; the first lens element with negative refractive power has a concave image-side surface at paraxial region; the second lens element with positive refractive power has a concave image-side surface at paraxial region; the third lens element with negative refractive power has a concave object-side surface and a concave image-side surface at paraxial region; the fourth lens element with positive refractive power; the fifth lens element with positive refractive power has convex object-side and image-side surfaces at paraxial region, and the sixth lens element with negative refractive power. According to the optical system, the surface shapes and the refractive powers of the first lens element to the sixth lens element are reasonably configured, so that the optical system can keep compact structure, and simultaneously the sizes of the incident angles and the emergent angles of the light rays in different fields of view can be reduced, so that the sensitivity can be reduced, and the requirement of high-definition image shooting can be met.

Description

Optical system, image capturing module and electronic equipment

Technical Field

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

Background

With the development of image capturing module industries such as vehicle-mounted devices, the technical requirements of image capturing modules applied to vehicles, such as ADAS, automobile data recorder, and back-up images, are higher and higher. Not only is there an increasing demand for miniaturization of optical systems, but also the pixel image quality of optical systems needs to be satisfied. However, in order to achieve miniaturization, a design of high resolution and low sensitivity is often not satisfied, and imaging quality is poor.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, an object of the present invention is to provide an optical system, which has a compact structure and can reduce the incident angle and the exit angle of light in different fields of view, thereby reducing the sensitivity, satisfying the requirement of high-definition image capturing, and having high resolution.

According to the optical system of the embodiment of the present invention, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are arranged in this order from the object side to the image side along the optical axis; the first lens element with negative refractive power has a concave image-side surface at paraxial region; the second lens element with positive refractive power has a concave image-side surface at paraxial region; the third lens element with negative refractive power has a concave object-side surface at a paraxial region thereof and a concave image-side surface at a paraxial region thereof; the fourth lens element with positive refractive power; the fifth lens element with positive refractive power has a convex object-side surface at a paraxial region thereof and a convex image-side surface at a paraxial region thereof; the sixth lens element has negative refractive power.

According to the optical system of the embodiment of the invention, the first lens element provides negative refractive power for the optical system, and the image side surface of the first lens element is concave, so that the miniaturization of the optical system is facilitated; the second lens element provides positive refractive power for the system, and has a concave image-side surface for correcting peripheral aberration of the optical system; the third lens provides negative refractive power for the system, and the object side surface and the image side surface of the third lens are both concave surfaces, so that the sizes of the incident angle and the emergent angle of light rays in different fields of view can be reduced, and the sensitivity is reduced; the fourth lens element with positive refractive power has a convex object-side surface at paraxial region thereof, and the fifth lens element with positive refractive power has a convex image-side surface at paraxial region thereof, so that the light converging capability of the optical system is enhanced, and the optical system can realize a telephoto characteristic; the sixth lens element with negative refractive power can correct the aberration of the front lens element, thereby further improving the resolution.

In some embodiments, the first lens has a focal length of f1, the optical system has an effective focal length of f, and f1, f satisfies the relationship: 3 < f1/f < -2, so that the bending force of the first lens can be reduced, and the sensitivity of image plane imaging caused by the change of the first lens is reduced, thereby reducing aberration.

In some embodiments, a combined focal length of the first lens and the second lens is f12, a combined focal length of the third lens, the fourth lens, the fifth lens, and the sixth lens is f36, the f12, the f36 satisfy the relation: 1 < f12/f36 < 1.5. By reasonably controlling the distribution ratio of the powers f12 and f36, the incidence width of light rays can be favorably controlled, and the high-order aberration of the optical system is reduced. Meanwhile, the emergent angle of the principal ray passing through the sixth lens can be reduced, and the relative brightness of the optical system is improved.

In some embodiments, the radius of the effective imaging circle of the optical system is Imgh, the diameter of the entrance pupil of the optical system is EPD, the maximum imaging range of the optical system is a circular image, the radius of the circle is Imgh, the diameter of the circle corresponds to the maximum field angle of the optical system, and Imgh and EPD satisfy the following relations: 0.5 < Imgh × 2/EPD < 1. By satisfying the relation conditional expression, the optical system can satisfy the requirements of high image surface and high-quality imaging, and simultaneously can ensure that the optical system can satisfy the image surface brightness with sufficient marginal field of view by controlling the diameter of the entrance pupil of the optical system, so as to prevent the entrance pupil diameter from being small and not beneficial to the improvement of the large-aperture optical system and the image surface brightness. Meanwhile, the diameter of the entrance pupil can be prevented from being too large, so that astigmatism of the marginal field-of-view ray bundle can be reduced, the improvement of the imaging quality of the optical system is facilitated, the image surface curvature is prevented, and the improvement of the resolution power of the optical system is facilitated.

In some embodiments, the third lens has a focal length f3, a thickness CT3 on an optical axis, and f3 and CT3 satisfy the following relation: -12.3 < f3/CT3 < -7.3. By satisfying the above relational expression, the refractive power of the third lens element can be prevented from being too large, so that the light beam deflection angle is prevented from being too large, and the optical system can be prevented from generating astigmatism which is difficult to correct or strong astigmatism and chromatic aberration, thereby being beneficial to realizing the high-resolution imaging characteristic of the optical system and further being beneficial to ensuring the imaging quality of the optical system. Simultaneously, the thickness of the third lens on the optical axis that so sets up is reasonable, can do benefit to optical system's lightweight setting, simultaneously, can prevent that center thickness undersize from leading to the lens processing technology degree of difficulty big.

In some embodiments, the fifth lens element and the sixth lens element are cemented together, which is beneficial to correcting aberration, reducing the assembly sensitivity of the optical system, solving the problems of lens fabrication and lens assembly, and improving yield. The combined focal length of the fifth lens and the sixth lens is f56, the effective focal length of the optical system is f, and the f56 and the f satisfy the relation: 3.5 < f56/f < 6. The combined focal length of the fifth lens and the sixth lens is reasonable, and the improvement of resolution can be facilitated.

In some embodiments, an axial distance between an object-side surface of the first lens element and an image plane is TTL, a sum of axial distances between an image-side surface of the first lens element and an object-side surface of the second lens element, between an image-side surface of the second lens element and an object-side surface of the third lens element and an object-side surface of the fourth lens element, between an image-side surface of the fourth lens element and an object-side surface of the fifth lens element, and between an image-side surface of the fifth lens element and an object-side surface of the sixth lens element is d16, where TTL and d16 satisfy the following relation: 11.4 < TTL/d16 < 15.4. By satisfying the above relational expression, the distance between two adjacent lenses is small, which can contribute to the compact structure of the optical system and the miniaturization of the optical system.

In some embodiments, the thickness of the third lens element along the optical axis is CT3, the thickness of the fourth lens element along the optical axis is CT4, the CT3 and the CT4 satisfy the following relations: 4.5 < CT4/CT3 < 7. Therefore, the reasonable thickness of the third lens and the fourth lens can effectively adjust the size relationship between the third lens and the fourth lens, so that the miniaturization design of the optical system can be facilitated, the optical performance can be improved, and in addition, the correction of the aberration of the optical system can be facilitated.

In some embodiments, the effective focal length of the optical system is f, the entrance pupil diameter of the optical system is EPD, and the EPD and the f satisfy the relation: f/EPD is more than or equal to 1.25 and less than or equal to 1.65. Can obtain less f-number through above setting, be favorable to increasing the light number that gets into the camera lens, improve optical system's the photic transmission volume of formation of image to do benefit to optical system and obtain clear image.

The image capturing module according to an embodiment of the present invention includes the optical system. According to the image capturing module provided by the embodiment of the invention, the surface shapes and the refractive powers of the first lens element to the sixth lens element are reasonably configured, so that the image capturing module can keep compact structure, the miniaturization design of the image capturing module is facilitated, the sizes of the incident angles and the emergent angles of the light rays with different viewing fields can be reduced, the sensitivity can be reduced, the requirement of high-definition image shooting can be met, and the resolution is high. And can meet the requirement of high-definition image shooting.

The electronic device according to the embodiment of the invention comprises the image capturing module. According to the electronic equipment provided by the embodiment of the invention, through reasonably configuring the surface shapes and the refractive powers of the first lens element to the sixth lens element, the electronic equipment can keep compact structure, so that the electronic equipment is beneficial to miniaturization design of the electronic equipment, and meanwhile, the sizes of the incident angles and the emergent angles of light rays with different fields of view can be reduced, so that the sensitivity can be reduced, the requirement of high-definition image shooting can be met, and the resolution is high. And can meet the requirement of high-definition image shooting.

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

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic configuration diagram of an optical system according to a first embodiment of the present invention;

fig. 2 is a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system according to a first embodiment of the present invention;

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

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

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

fig. 6 is a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system according to a third embodiment of the present invention;

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

fig. 8 is a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system according to a fourth embodiment of the present invention;

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

fig. 10 is a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system according to a fifth embodiment of the present invention;

fig. 11 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.

Reference numerals:

an optical system 1; an image capturing module 2; an electronic device 100;

a first lens L1; the object side S1 of the first lens; the image-side surface S2 of the first lens;

a second lens L2; the object side S3 of the second lens; the image-side surface S4 of the second lens;

a third lens L3; the object-side surface S5 of the third lens; the image-side surface S6 of the third lens;

a fourth lens L4; the object-side surface S7 of the fourth lens; the image-side surface S8 of the fourth lens;

a fifth lens L5; the object-side surface S9 of the fifth lens; the image-side surface S10 of the fifth lens;

a sixth lens L6; the object-side surface S11 of the sixth lens; the image-side surface S12 of the sixth lens;

an optical axis 10; a diaphragm 20; an infrared filter 30; a cover glass 40; and an image plane 50.

Detailed Description

Embodiments of the present invention are described in detail below, the embodiments described with reference to the drawings are exemplary, and an optical system 1 according to an embodiment of the present invention, including 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, which are arranged in this order from the object side to the image side along an optical axis 10, is described below with reference to fig. 1 to 11.

Specifically, the first lens element L1 with negative refractive power has a concave image-side surface S2 at the optical axis 10. The second lens element L2 with positive refractive power has a concave image-side surface S4 at the optical axis 10. The third lens element L3 with negative refractive power has a concave object-side surface S5 at the optical axis 10 and a concave image-side surface S6 at the optical axis 10. The fourth lens element L4 has positive refractive power. The fifth lens element L5 with positive refractive power has a convex object-side surface S9 at the optical axis 10 and a convex image-side surface S10 at the optical axis 10. The sixth lens element L6 has negative refractive power. In addition, the optical system 1 may further include an image plane 50 and a stop 20, the image plane 50 is located on the image side of the sixth lens L6, and an on-axis object point at infinity can be focused on the image plane 50 after being adjusted by six lenses. The stop 20 may be located between the second lens L2 and the third lens L3. For example, the image plane 50 may coincide with a photosensitive plane of a photosensitive element of the image capturing module 2. By setting the second lens element L2, the fourth lens element L4, and the fifth lens element L5 to have positive refractive power, the light rays of the optical system 1 can be converged, the total length of the optical system 1 can be reduced, and the optical system 1 can be made compact.

The first lens element L1 with concave image-side surface provides negative refractive power for the optical system 1, which is favorable for miniaturization of the optical system 1. The second lens element L2 with its image-side surface being concave provides positive refractive power for the optical system 1, and is favorable for correcting the peripheral aberration of the optical system 1. The third lens element L3 with negative refractive power provides the optical system 1 with concave object-side and image-side surfaces, which can reduce the incident angle and the exit angle of light in different fields of view, thereby reducing the sensitivity. The fourth lens element L4 with positive refractive power and the fifth lens element L5 with positive refractive power have a convex object-side surface at a paraxial region of the fifth lens element L5 and a convex image-side surface at a paraxial region of the fifth lens element L5, so that the converging ability of the optical system 1 on light rays is enhanced, which is helpful for realizing the telephoto characteristic of the optical system 1; the sixth lens element L6 with negative refractive power helps correct aberrations of the first lens element L1 through the fifth lens element L5, thereby further improving resolving power.

For example, at least one of the first lens L1 to the sixth lens L6 may be made of glass, so that the lens has a good endurance effect, and is prevented from aging, deformation and the like, so as to ensure the stability of the performance of the optical system 1. The deformation and the refractive power of the glass lens are small in the environment with over-high temperature or over-low temperature, so that the problem of aberration increase caused by over-concentration of refractive power can be avoided, and the imaging performance of the system can be more stable.

According to the optical system 1 of the embodiment of the present invention, by reasonably configuring the surface shapes and refractive powers of the first lens element L1 through the sixth lens element L6, the optical system 1 can keep compact structure, so as to facilitate the miniaturization design of the optical system 1, and simultaneously, the sizes of the incident angles and the exit angles of the light rays in different fields of view can be reduced, so that the sensitivity can be reduced, the requirement of high-definition image shooting can be met, and the resolution is high.

In some embodiments, the fifth lens element L5 and the sixth lens element L6 are cemented together, which is beneficial to correcting aberration, reducing the assembly sensitivity of the optical system 1, solving the problems of lens fabrication and lens assembly, and improving yield.

In some embodiments, the focal length of the first lens L1 is f1, the effective focal length of the optical system 1 is f, and f1 and f satisfy the following relation: -3 < f1/f < -2. Since the first lens element L1 has negative refractive power, the focal length of the first lens element L1 is smaller to reduce the refractive power of the first lens element L1, so as to reduce the sensitivity of the image formation on the image plane 50 due to the change of the first lens element L1, thereby reducing the aberration.

In some embodiments, the combined focal length of the first lens L1 and the second lens L2 is f12, the combined focal length of the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 is f36, and f12 and f36 satisfy the following relations: 1 < f12/f36 < 1.5. By reasonably controlling the distribution ratio of the powers f12 and f36, the incidence width of the light rays can be favorably controlled, and the high-order aberration of the optical system 1 can be reduced. Meanwhile, the exit angle of the principal ray passing through the sixth lens L6 can be reduced, and the relative brightness of the optical system 1 can be improved.

In some embodiments, half of the radius of the effective imaging circle of the optical system 1 is Imgh, the diameter of the entrance pupil of the optical system 1 is EPD, the maximum imaging range of the optical system 1 is a circular image, the radius of the circle is Imgh, the diameter of the circle corresponds to the maximum field angle of the optical system 1, and Imgh and EPD satisfy the following relations: 0.5 < Imgh × 2/EPD < 1. By satisfying the relation conditional expression, the optical system 1 can ensure that the optical system 1 satisfies the brightness of the image plane 50 with sufficient marginal field of view by controlling the diameter of the entrance pupil of the optical system 1 while satisfying the high-quality imaging of the large image plane 50, so as to prevent the entrance pupil diameter from being smaller and not beneficial to the brightness improvement of the large-aperture optical system 1 and the image plane 50. Meanwhile, the diameter of the entrance pupil can be prevented from being too large, so that astigmatism of the marginal field-of-view ray bundle can be reduced, the improvement of the imaging quality of the optical system 1 is facilitated, the image plane 50 is prevented from being curved, and the improvement of the resolution of the optical system 1 is facilitated.

In some embodiments, the focal length of the third lens L3 is f3, the thickness of the third lens L3 on the optical axis 10 is CT3, and f3 and CT3 satisfy the following relations: -12.3 < f3/CT3 < -7.3. By satisfying the above relationship, the refractive power of the third lens element L3 can be prevented from being too large, so as to prevent the light beam from being too large in a folding angle and prevent the optical system 1 from generating astigmatism which is difficult to correct or strong astigmatism and chromatic aberration, thereby facilitating the realization of the high-resolution imaging characteristic of the optical system 1 and further facilitating the guarantee of the imaging quality of the optical system 1. Meanwhile, the larger the center thickness is, the larger the weight of the lens is, and the thickness of the third lens L3 on the optical axis 10 is reasonable, so that the lightweight setting of the optical system 1 can be facilitated, and meanwhile, the difficulty in the lens processing process caused by the excessively small center thickness can be prevented from being large.

In some embodiments, the combined focal length of the fifth lens L5 and the sixth lens L6 is f56, the effective focal length of the optical system 1 is f, and f56 and f satisfy the following relation: 3.5 < f56/f < 6. The fifth lens L5 provides positive and the sixth lens L6 provides negative refractive power to the system, and the fifth lens L5 and the sixth lens L6 are cemented together to better correct aberrations. If the upper limit of the conditional expression is exceeded, the combined focal length of the fifth lens element L5 and the sixth lens element L6 is too large, the refractive power is too small, which is likely to generate large edge aberration and chromatic aberration, and is not favorable for improving the resolution performance; when the lower limit of the conditional expression is exceeded, the focal length of the cemented lens assembly is too small, and the total refractive power of the fifth lens element L5 and the sixth lens element L6 is too strong, so that the lens assembly is prone to generate a severe astigmatism phenomenon, which is not favorable for improving the imaging quality. Therefore, the combined focal length of the fifth lens L5 and the sixth lens L6 is reasonable, which is beneficial to improving the resolution.

In some embodiments, the distance between the object-side surface S1 of the first lens element and the image plane 50 on the optical axis 10 is TTL, the sum of the distances on the optical axis 10 from the image-side surface S2 of the first lens element to the object-side surface S3 of the second lens element, from the image-side surface S4 of the second lens element to the object-side surface S5 of the third lens element, from the image-side surface S6 of the third lens element to the object-side surface S7 of the fourth lens element, from the image-side surface S8 of the fourth lens element to the object-side surface S9 of the fifth lens element, and from the image-side surface S10 of the fifth lens element to the object-side surface S11 of the sixth lens element is d16, and TTL and d16 satisfy the following relations: 11.4 < TTL/d16 < 15.4. By satisfying the above relational expression, the distance between two adjacent lenses is small, which can contribute to the compact structure of the optical system 1 and realize the miniaturized design of the optical system 1.

In some embodiments, the thickness of the third lens element L3 on the optical axis 10 is CT3, the thickness of the fourth lens element L4 on the optical axis 10 is CT4, and CT3 and CT4 satisfy the following relations: 4.5 < CT4/CT3 < 7. Therefore, the reasonable thickness of the third lens element L3 and the fourth lens element L4 can effectively adjust the refractive power relationship between the third lens element L3 and the fourth lens element L4, which is favorable for the miniaturization design of the optical system 1, and can improve the optical performance and, in addition, can be favorable for the aberration correction of the optical system 1.

In some embodiments, the effective focal length of the optical system 1 is f, the entrance pupil diameter of the optical system 1 is EPD, and EPD, f satisfy the relation: f/EPD is more than or equal to 1.25 and less than or equal to 1.65. Can obtain less f-number through above setting, be favorable to increasing the light number that gets into the camera lens, improve optical system 1's the photic transmission volume of formation of image to do benefit to optical system 1 and obtain clear image.

An optical system 1 of various embodiments of the present invention is described below with reference to fig. 1-10.

In the first embodiment, the first step is,

in the present embodiment, as shown in fig. 1, the optical system 1 includes, in order from the object side surface to the image side surface, a first lens L1, a second lens L2, a stop 20, a third lens L3, a fourth lens L4, a fifth lens L5, an infrared filter 30, a protective glass 40, and an image plane 50, and the longitudinal spherical aberration, astigmatism, and distortion curve of the optical system 1 are shown in fig. 2.

The first lens element L1 with negative refractive power has a convex object-side surface S1 at a paraxial region 10 and a concave image-side surface S2 at the paraxial region 10. The second lens element L2 with positive refractive power has a convex object-side surface S3 at a paraxial region 10 and a concave image-side surface S4 at a paraxial region 10. The third lens element L3 with negative refractive power has a concave object-side surface S5 at a paraxial region 10 and a concave image-side surface S6 at a paraxial region 10. The fourth lens element L4 has positive refractive power; the object-side surface S7 of the fourth lens element is convex at the paraxial region 10, and the image-side surface S8 of the fourth lens element is convex at the paraxial region 10. The fifth lens element L5 with positive refractive power has a convex object-side surface S9 at a paraxial region 10 and a convex image-side surface S10 at a paraxial region 10. The sixth lens element L6 has negative refractive power. The object-side surface S11 of the sixth lens element is concave at the paraxial region 10, and the image-side surface S12 of the sixth lens element is concave at the paraxial region 10.

Detailed optical data of the first embodiment are shown in table 1, and aspherical coefficients thereof are shown in table 2, a unit of a radius of curvature and a thickness is mm, a reference wavelength of an effective focal length of the optical system 1 is 542.02nm, and a reference wavelength of an abbe number and a refractive index of the lens is 587.600 nm. Wherein, the aspheric surface formula is:

z is the distance from the corresponding point on the aspheric surface to the plane tangent to the surface vertex, r is the distance from the corresponding point on the aspheric surface to the optical axis 10, c is the curvature of the aspheric surface vertex, k is the conic constant, and Ai is the coefficient corresponding to the i-th high order term in the aspheric surface profile formula.

TABLE 1

TABLE 2

Number of noodles	3	4	8	9
					K	0.00E+00	0.00E+00	0.00E+00	-2.21E-01
A4	9.07E-05	3.49E-05	-3.91E-04	-5.01E-06
					A6	7.04E-07	3.06E-06	0.00E+00	-8.58E-06
A8	0.00E+00	0.00E+00	0.00E+00	9.84E-07
					A10	0.00E+00	0.00E+00	0.00E+00	-5.18E-08
A12	0.00E+00	0.00E+00	0.00E+00	1.11E-09
					A14	0.00E+00	0.00E+00	0.00E+00	-3.58E-11
A16	0.00E+00	0.00E+00	0.00E+00	2.88E-13
					A18	0.00E+00	0.00E+00	0.00E+00	0.00E+00
A20	0.00E+00	0.00E+00	0.00E+00	0.00E+00

Fig. 2 shows a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system 1 of the first embodiment. Wherein, the longitudinal spherical aberration curve represents the deviation of the convergence focus of the light rays with different wavelengths after passing through each lens of the optical system 1, and the reference wavelengths of the longitudinal spherical aberration curve are 642.7300nm, 590.8600nm, 542.0200nm, 500.4800nm and 465.6100 nm; the astigmatism curves represent meridional image surface curvature and sagittal image surface curvature, wherein S represents sagittal direction, T represents meridional direction, and the reference wavelength of the astigmatism curves is 542.0200 nm; the distortion curve represents the distortion magnitude values corresponding to different angles of view, and the reference wavelength of the distortion curve is 542.0200 nm. As can be seen from fig. 2, the optical system 1 of the first embodiment can achieve good image quality.

The focal length of the first lens L1 is f1, the effective focal length of the optical system 1 is f, and f1/f is-2.529.

The combined focal length of the first lens L1 and the second lens L2 is f12, the combined focal length of the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 is f36, and f12/f36 is 1.117.

The radius of the effective imaging circle of the optical system 1 is Imgh, the entrance pupil diameter of the optical system 1 is EPD, and Imgh × 2/EPD is 0.928.

The focal length of the third lens L3 is f3, the thickness of the third lens L3 on the optical axis 10 is CT3, and f3/CT3 is-7.473.

The combined focal length of the fifth lens L5 and the sixth lens L6 is f56, the effective focal length of the optical system 1 is f, and f56/f is 5.208.

The distance between the object-side surface S1 of the first lens element and the image plane 50 on the optical axis 10 is TTL, the sum of the distances on the optical axis 10 from the image-side surface S2 of the first lens element to the object-side surface S3 of the second lens element, from the image-side surface S4 of the second lens element to the object-side surface S5 of the third lens element, from the image-side surface S6 of the third lens element to the object-side surface S7 of the fourth lens element, from the image-side surface S8 of the fourth lens element to the object-side surface S9 of the fifth lens element, and from the image-side surface S10 of the fifth lens element to the object-side surface S11 of the sixth lens element is d16, and TTL/d16 is 15.115.

The thickness of the third lens L3 on the optical axis 10 is CT3, the thickness of the fourth lens L4 on the optical axis 10 is CT4, and CT4/CT3 is 5.768.

The effective focal length of the optical system 1 is f, the entrance pupil diameter of the optical system 1 is EPD, and f/EPD is 1.650.

Example two

In the present embodiment, as shown in fig. 3, the optical system 1 includes, in order from the object side surface to the image side surface, a first lens L1, a second lens L2, a stop 20, a third lens L3, a fourth lens L4, a fifth lens L5, an infrared filter 30, a protective glass 40, and an image plane 50, and the longitudinal spherical aberration, astigmatism, and distortion curve of the optical system 1 are shown in fig. 4.

The first lens element L1 with negative refractive power has a convex object-side surface S1 at a paraxial region 10 and a concave image-side surface S2 at the paraxial region 10. The second lens element L2 with positive refractive power has a convex object-side surface S3 at a paraxial region 10 and a concave image-side surface S4 at a paraxial region 10. The third lens element L3 with negative refractive power has a concave object-side surface S5 at a paraxial region 10 and a concave image-side surface S6 at a paraxial region 10. The fourth lens element L4 has positive refractive power; the object-side surface S7 of the fourth lens element is concave at the paraxial region 10, and the image-side surface S8 of the fourth lens element is convex at the paraxial region 10. The fifth lens element L5 with positive refractive power has a convex object-side surface S9 at a paraxial region 10 and a convex image-side surface S10 at a paraxial region 10. The sixth lens element L6 has negative refractive power. The object-side surface S11 of the sixth lens element is concave at the paraxial region 10, and the image-side surface S12 of the sixth lens element is concave at the paraxial region 10.

The detailed optical data of example two are shown in table 3, the aspherical coefficients are shown in table 4, the unit of the radius of curvature and the thickness is mm, the reference wavelength of the effective focal length of the optical system 1 is 542.02nm, and the reference wavelength of the abbe number and the refractive index of the lens is 587.600 nm. Wherein, the aspheric surface formula is:

TABLE 3

TABLE 4

Number of noodles	3	4	8	9
					K	0.00E+00	0.00E+00	-5.18E+01	-6.69E-01
A4	5.05E-05	3.37E-05	-5.88E-04	-9.80E-05
					A6	7.23E-07	2.14E-06	-5.22E-06	-9.03E-06
A8	0.00E+00	0.00E+00	4.82E-08	9.07E-07
					A10	0.00E+00	0.00E+00	-4.84E-09	-5.45E-08
A12	0.00E+00	0.00E+00	-2.47E-11	1.56E-09
					A14	0.00E+00	0.00E+00	-4.22E-12	-3.14E-11
A16	0.00E+00	0.00E+00	8.15E-14	2.43E-13
					A18	0.00E+00	0.00E+00	0.00E+00	0.00E+00
A20	0.00E+00	0.00E+00	0.00E+00	0.00E+00

Fig. 4 shows a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system 1 of the second embodiment. Wherein, the longitudinal spherical aberration curve represents the deviation of the convergence focus of the light rays with different wavelengths after passing through each lens of the optical system 1, and the reference wavelengths of the longitudinal spherical aberration curve are 642.7300nm, 590.8600nm, 542.0200nm, 500.4800nm and 465.6100 nm; the astigmatism curves represent meridional image surface curvature and sagittal image surface curvature, wherein S represents sagittal direction, T represents meridional direction, and the reference wavelength of the astigmatism curves is 542.0200 nm; the distortion curve represents the distortion magnitude values corresponding to different angles of view, and the reference wavelength of the distortion curve is 542.0200 nm. As can be seen from fig. 4, the optical system 1 of the second embodiment can achieve good image quality.

The focal length of the first lens L1 is f1, the effective focal length of the optical system 1 is f, and f1/f is-2.275.

The combined focal length of the first lens L1 and the second lens L2 is f12, the combined focal length of the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 is f36, and f12/f36 is 1.098.

The radius of the effective imaging circle of the optical system 1 is Imgh, the entrance pupil diameter of the optical system 1 is EPD, and Imgh × 2/EPD is 0.850.

The focal length of the third lens L3 is f3, and the thickness of the third lens L3 on the optical axis 10 is CT3, where f3/CT3 is-7.842.

The combined focal length of the fifth lens L5 and the sixth lens L6 is f56, the effective focal length of the optical system 1 is f, and f56/f is 3.948.

The distance between the object-side surface S1 of the first lens element and the image plane 50 on the optical axis 10 is TTL, the sum of the distances on the optical axis 10 from the image-side surface S2 of the first lens element to the object-side surface S3 of the second lens element, from the image-side surface S4 of the second lens element to the object-side surface S5 of the third lens element, from the image-side surface S6 of the third lens element to the object-side surface S7 of the fourth lens element, from the image-side surface S8 of the fourth lens element to the object-side surface S9 of the fifth lens element, and from the image-side surface S10 of the fifth lens element to the object-side surface S11 of the sixth lens element is d16, and TTL/d16 is 14.098.

The thickness of the third lens L3 on the optical axis 10 is CT3, the thickness of the fourth lens L4 on the optical axis 10 is CT4, and CT4/CT3 is 4.571.

The effective focal length of the optical system 1 is f, the entrance pupil diameter of the optical system 1 is EPD, and f/EPD is 1.500.

In the third embodiment, the first step is that,

in the present embodiment, as shown in fig. 5, the optical system 1 includes, in order from the object side surface to the image side surface, a first lens L1, a second lens L2, a stop 20, a third lens L3, a fourth lens L4, a fifth lens L5, an infrared filter 30, and an image plane 50, and the longitudinal spherical aberration, astigmatism, and distortion curve of the optical system 1 are shown in fig. 6.

The detailed optical data of example III are shown in Table 5, the aspherical coefficients are shown in Table 6, the unit of the radius of curvature and the thickness is mm, the reference wavelength of the effective focal length of the optical system 1 is 542.02nm, and the reference wavelength of the Abbe number and the refractive index of the lens is 587.600 nm. Wherein, the aspheric surface formula is:

TABLE 5

TABLE 6

Number of noodles	3	4	8	9
					K	0.00E+00	0.00E+00	5.03E+01	-4.16E-01
A4	1.63E-05	7.79E-04	-6.15E-04	-4.49E-05
					A6	6.05E-07	2.59E-06	-1.21E-06	-2.37E-06
A8	0.00E+00	0.00E+00	-8.03E-07	1.41E-07
					A10	0.00E+00	0.00E+00	1.33E-07	-1.00E-08
A12	0.00E+00	0.00E+00	-2.03E-08	3.85E-10
					A14	0.00E+00	0.00E+00	1.22E-09	-8.38E-12
A16	0.00E+00	0.00E+00	-6.20E-11	8.67E-14
					A18	0.00E+00	0.00E+00	1.64E-12	-1.81E-16
A20	0.00E+00	0.00E+00	-1.41E-14	-2.74E-18

Fig. 6 shows a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system 1 of the third embodiment. Wherein, the longitudinal spherical aberration curve represents the deviation of the convergence focus of the light rays with different wavelengths after passing through each lens of the optical system 1, and the reference wavelengths of the longitudinal spherical aberration curve are 642.7300nm, 590.8600nm, 542.0200nm, 500.4800nm and 465.6100 nm; the astigmatism curves represent the bending of the meridional image plane 50 and the bending of the sagittal image plane 50, wherein S represents the sagittal direction, T represents the meridional direction, and the reference wavelength of the astigmatism curves is 542.0200 nm; the distortion curve represents the distortion magnitude values corresponding to different angles of view, and the reference wavelength of the distortion curve is 542.0200 nm. As can be seen from fig. 6, the optical system 1 of the third embodiment can achieve good image quality.

The focal length of the first lens L1 is f1, the effective focal length of the optical system 1 is f, and f1/f is-2.037.

The combined focal length of the first lens L1 and the second lens L2 is f12, the combined focal length of the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 is f36, and f12/f36 is 1.336.

The radius of the effective imaging circle of the optical system 1 is Imgh, the entrance pupil diameter of the optical system 1 is EPD, and Imgh × 2/EPD is 0.801.

The focal length of the third lens L3 is f3, the thickness of the third lens L3 on the optical axis 10 is CT3, and f3/CT3 is-9.017.

The combined focal length of the fifth lens L5 and the sixth lens L6 is f56, the effective focal length of the optical system 1 is f, and f56/f is 5.941.

The distance between the object-side surface S1 of the first lens element and the image plane 50 on the optical axis 10 is TTL, the sum of the distances on the optical axis 10 from the image-side surface S2 of the first lens element to the object-side surface S3 of the second lens element, from the image-side surface S4 of the second lens element to the object-side surface S5 of the third lens element, from the image-side surface S6 of the third lens element to the object-side surface S7 of the fourth lens element, from the image-side surface S8 of the fourth lens element to the object-side surface S9 of the fifth lens element, and from the image-side surface S10 of the fifth lens element to the object-side surface S11 of the sixth lens element is d16, and TTL/d16 is 13.176.

The thickness of the third lens L3 on the optical axis 10 is CT3, the thickness of the fourth lens L4 on the optical axis 10 is CT4, and CT4/CT3 is 4.748.

The effective focal length of the optical system 1 is f, the entrance pupil diameter of the optical system 1 is EPD, and f/EPD is 1.400.

In the fourth embodiment, the first step is that,

in the present embodiment, as shown in fig. 7, the optical system 1 includes, in order from the object side surface to the image side surface, a first lens L1, a second lens L2, a stop 20, a third lens L3, a fourth lens L4, a fifth lens L5, an infrared filter 30, a protective glass 40, and an image plane 50, and the longitudinal spherical aberration, astigmatism, and distortion curve of the optical system 1 are shown in fig. 8.

The detailed optical data of example four are shown in table 7, the aspherical coefficients are shown in table 8, the unit of the radius of curvature and the thickness is mm, the reference wavelength of the effective focal length of the optical system 1 is 542.02nm, and the reference wavelength of the abbe number and the refractive index of the lens is 587.600 nm. Wherein, the aspheric surface formula is:

TABLE 7

TABLE 8

Fig. 8 shows a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system 1 of the fourth embodiment. Wherein, the longitudinal spherical aberration curve represents the deviation of the convergence focus of the light rays with different wavelengths after passing through each lens of the optical system 1, and the reference wavelengths of the longitudinal spherical aberration curve are 642.7300nm, 590.8600nm, 542.0200nm, 500.4800nm and 465.6100 nm; the astigmatism curves represent the bending of the meridional image plane 50 and the bending of the sagittal image plane 50, wherein S represents the sagittal direction, T represents the meridional direction, and the reference wavelength of the astigmatism curves is 542.0200 nm; the distortion curve represents the distortion magnitude values corresponding to different angles of view, and the reference wavelength of the distortion curve is 542.0200 nm. As can be seen from fig. 8, the optical system 1 of the fourth embodiment can achieve good image quality.

The focal length of the first lens L1 is f1, the effective focal length of the optical system 1 is f, and f1/f is-2.743.

The combined focal length of the first lens L1 and the second lens L2 is f12, the combined focal length of the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 is f36, and f12/f36 is 1.289.

The radius of the effective imaging circle of the optical system 1 is Imgh, the entrance pupil diameter of the optical system 1 is EPD, and Imgh × 2/EPD is 0.744.

The focal length of the third lens L3 is f3, the thickness of the third lens L3 on the optical axis 10 is CT3, and f3/CT3 is-11.532.

The combined focal length of the fifth lens L5 and the sixth lens L6 is f56, the effective focal length of the optical system 1 is f, and f56/f is 4.734.

The distance between the object-side surface S1 of the first lens element and the image plane 50 on the optical axis 10 is TTL, the sum of the distances on the optical axis 10 from the image-side surface S2 of the first lens element to the object-side surface S3 of the second lens element, from the image-side surface S4 of the second lens element to the object-side surface S5 of the third lens element, from the image-side surface S6 of the third lens element to the object-side surface S7 of the fourth lens element, from the image-side surface S8 of the fourth lens element to the object-side surface S9 of the fifth lens element, and from the image-side surface S10 of the fifth lens element to the object-side surface S11 of the sixth lens element is d16, and TTL/d16 is 11.566.

The thickness of the third lens L3 on the optical axis 10 is CT3, the thickness of the fourth lens L4 on the optical axis 10 is CT4, and CT4/CT3 is 6.542.

The effective focal length of the optical system 1 is f, the entrance pupil diameter of the optical system 1 is EPD, and f/EPD is 1.300.

In the fifth embodiment, the first step is,

in the present embodiment, as shown in fig. 9, the optical system 1 includes a first lens L1, a second lens L2, a stop 20, a third lens L3, a fourth lens L4, and a fifth lens L5, an infrared filter 30, a protective glass 40, and an image plane 50 in this order from the object side surface to the image side surface, and the longitudinal spherical aberration, astigmatism, and distortion curve of the optical system 1 are shown in fig. 10.

Example five detailed optical data are shown in table 9, aspheric coefficients thereof are shown in table 10, a unit of a radius of curvature and a thickness is mm, and a reference wavelength of an effective focal length of the optical system 1 is 542.02nm, and the reference wavelength for the Abbe number and refractive index of the lens is 587.600 nm. Wherein, the aspheric surface formula is:

TABLE 9

Watch 10

Number of noodles	3	4	8	9
					K	-3.16E-03	-4.07E-02	5.76E+01	-2.46E-01
A4	7.87E-05	1.15E-05	-4.51E-04	-3.55E-05
					A6	-3.61E-06	-3.43E-06	4.50E-05	1.28E-07
A8	5.03E-07	8.10E-07	-8.09E-06	-3.02E-07
					A10	-3.96E-08	-9.57E-08	6.32E-06	2.22E-08
A12	1.89E-09	6.60E-09	-1.05E-07	-1.52E-09
					A14	-6.03E-11	-2.66E-10	5.86E-09	4.74E-11
A16	1.79E-12	6.33E-12	-2.08E-10	-8.18E-13
					A18	-1.40E-14	-7.32E-14	3.24E-12	8.62E-15
A20	4.92E-17	2.48E-16	-3.88E-14	-3.94E-17

Fig. 10 shows a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system 1 of the fifth embodiment. Wherein, the longitudinal spherical aberration curve represents the deviation of the convergence focus of the light rays with different wavelengths after passing through each lens of the optical system 1, and the reference wavelengths of the longitudinal spherical aberration curve are 642.7300nm, 590.8600nm, 542.0200nm, 500.4800nm and 465.6100 nm; the astigmatism curves represent the bending of the meridional image plane 50 and the bending of the sagittal image plane 50, wherein S represents the sagittal direction, T represents the meridional direction, and the reference wavelength of the astigmatism curves is 542.0200 nm; the distortion curve represents the distortion magnitude values corresponding to different angles of view, and the reference wavelength of the distortion curve is 542.0200 nm. As can be seen from fig. 10, the optical system 1 of the fifth embodiment can achieve good image quality.

The focal length of the first lens L1 is f1, the effective focal length of the optical system 1 is f, and f1/f is-2.839.

The combined focal length of the first lens L1 and the second lens L2 is f12, the combined focal length of the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 is f36, and f12/f36 is 1.339.

The radius of the effective imaging circle of the optical system 1 is Imgh, the entrance pupil diameter of the optical system 1 is EPD, and Imgh × 2/EPD is 0.715.

The focal length of the third lens L3 is f3, the thickness of the third lens L3 on the optical axis 10 is CT3, and f3/CT3 is-12.132.

The combined focal length of the fifth lens L5 and the sixth lens L6 is f56, the effective focal length of the optical system 1 is f, and f56/f is 4.761.

The distance between the object-side surface S1 of the first lens element and the image plane 50 on the optical axis 10 is TTL, the sum of the distances on the optical axis 10 from the image-side surface S2 of the first lens element to the object-side surface S3 of the second lens element, from the image-side surface S4 of the second lens element to the object-side surface S5 of the third lens element, from the image-side surface S6 of the third lens element to the object-side surface S7 of the fourth lens element, from the image-side surface S8 of the fourth lens element to the object-side surface S9 of the fifth lens element, and from the image-side surface S10 of the fifth lens element to the object-side surface S11 of the sixth lens element is d16, and TTL/d16 is 11.734.

The thickness of the third lens L3 on the optical axis 10 is CT3, the thickness of the fourth lens L4 on the optical axis 10 is CT4, and CT4/CT3 is 6.900.

The effective focal length of the optical system 1 is f, the entrance pupil diameter of the optical system 1 is EPD, and f/EPD is 1.250.

The image capturing module 2 according to the embodiment of the invention includes the optical system 1. As shown in fig. 11, the image capturing module 2 may include a photosensitive element, and the image plane 50 of the optical system 1 may coincide with the photosensitive surface of the image capturing module 2. According to the image capturing module 2 of the embodiment of the invention, by reasonably configuring the surface shapes and the refractive powers of the first lens element L1 to the sixth lens element L6, the optical system 1 can keep compact structure, so as to facilitate the miniaturization design of the optical system 1, and simultaneously, the sizes of the incident angles and the emergent angles of the light rays in different fields of view can be reduced, so that the sensitivity can be reduced, the requirements of high-definition image shooting can be met, and the resolution is high.

The electronic device 100 according to the embodiment of the invention includes the image capturing module 2. For example, the electronic device 100 may be a high-pixel camera lens, an automatic Driving device, a monitoring device, a mobile phone, or the like, or the electronic device may be an in-vehicle camera applied to a vehicle, such as an ADAS (Advanced Driving Assistance System), a drive recorder, or a reverse image. The optical system 1 is applied to an ADAS system, can accurately capture road information (a detected object, a detected light source, a detected road mark and the like) in real time to be supplied to an automobile system for image analysis and judgment, responds in time, and provides guarantee for automatic driving safety. The optical system 1 is applied to the driving record, can provide a clear view for the driving of a driver, and provides guarantee for the safe driving of the driver; the optical system 1 is applied to monitoring and security protection, can clearly record detailed information, and provides corresponding technical support and application guarantee in the aspect of practical application.

According to the electronic device 100 of the embodiment of the invention, by reasonably configuring the surface shapes and the refractive powers of the first lens element L1 through the sixth lens element L6, the optical system 1 can be kept compact, which is beneficial to the miniaturization design of the electronic device, and has high resolution and low sensitivity.

In the description of the present invention, it is to be understood that the terms "center", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, "the first feature" and "the second feature" may include one or more of the features. In the description of the present invention, "a plurality" means two or more. In the description of the present invention, the first feature being "on" or "under" the second feature may include the first and second features being in direct contact, and may also include the first and second features being in contact with each other not directly but through another feature therebetween. In the description of the invention, "above", "over" and "above" a first feature in a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like 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 do not necessarily refer to the same embodiment or example.

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:

a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens which are arranged in this order from an object side to an image side along an optical axis;

the first lens element with negative refractive power has a concave image-side surface at paraxial region;

the second lens element with positive refractive power has a concave image-side surface at paraxial region;

the third lens element with negative refractive power has a concave object-side surface at a paraxial region thereof and a concave image-side surface at a paraxial region thereof;

the fourth lens element with positive refractive power;

the fifth lens element with positive refractive power has a convex object-side surface at a paraxial region thereof and a convex image-side surface at a paraxial region thereof;

the sixth lens element has negative refractive power.

2. The optical system of claim 1, wherein the first lens has a focal length of f1, the optical system has an effective focal length of f,

the f1 and the f satisfy the relation: -3 < f1/f < -2.

3. The optical system of claim 1, wherein a combined focal length of the first lens and the second lens is f12, a combined focal length of the third lens, the fourth lens, the fifth lens, and the sixth lens is f36,

the f12 and the f36 satisfy the relation: 1 < f12/f36 < 1.5.

4. The optical system of claim 1, wherein the radius of the effective imaging circle of the optical system is Imgh, the entrance pupil diameter of the optical system is EPD,

the Imgh and the EPD satisfy the relation: 0.5 < Imgh × 2/EPD < 1.

5. The optical system of claim 1, wherein the third lens has a focal length of f3, a thickness of CT3 on an optical axis,

the f3 and the CT3 satisfy the relation: -12.3 < f3/CT3 < -7.3.

6. The optical system of claim 1, wherein the fifth lens and the sixth lens are cemented to each other, a combined focal length of the fifth lens and the sixth lens is f56, an effective focal length of the optical system is f,

the f56 and the f satisfy the relation: 3.5 < f56/f < 6.

7. The optical system of claim 1, wherein an on-axis distance from an object-side surface of the first lens element to an image plane is TTL, a sum of distances on an optical axis from an image-side surface of the first lens element to an object-side surface of the second lens element, from an image-side surface of the second lens element to an object-side surface of the third lens element, from an image-side surface of the third lens element to an object-side surface of the fourth lens element, from an image-side surface of the fourth lens element to an object-side surface of the fifth lens element, and from an image-side surface of the fifth lens element to an object-side surface of the sixth lens element is d16,

the TTL and the d16 satisfy the relation: 11.4 < TTL/d16 < 15.4.

8. The optical system of claim 1, wherein the third lens element has a thickness CT3 and the fourth lens element has a thickness CT4,

the CT3, the CT4 satisfy the relation: 4.5 < CT4/CT3 < 7.

9. The optical system of claim 1, wherein the optical system has an effective focal length f, an entrance pupil diameter EPD,

the EPD and the f satisfy the relation: f/EPD is more than or equal to 1.25 and less than or equal to 1.65.

10. An image capturing module comprising the optical system of any one of claims 1-9.

11. An electronic device, comprising the image capturing module as claimed in claim 10.