CN116338912A

CN116338912A - Optical lens

Info

Publication number: CN116338912A
Application number: CN202310620344.1A
Authority: CN
Inventors: 谢雨辰; 龚佳豪; 章彬炜
Original assignee: Jiangxi Lianyi Optics Co Ltd
Current assignee: Jiangxi Lianyi Optics Co Ltd
Priority date: 2023-05-30
Filing date: 2023-05-30
Publication date: 2023-06-27
Anticipated expiration: 2043-05-30
Also published as: CN116338912B

Abstract

The invention discloses an optical lens, which sequentially comprises from an object side to an image side along an optical axis: a first lens, a second lens, a stop, a third lens, a fourth lens, a fifth lens, and a sixth lens; the first lens has negative focal power, the object side surface of the first lens is concave at a paraxial region, and the image side surface of the first lens is convex at the paraxial region; the second lens has positive focal power, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; the third lens has positive focal power, and the object side surface and the image side surface of the third lens are convex; the fourth lens has negative focal power, the object side surface of the fourth lens is a concave surface, and the image side surface of the fourth lens is a convex surface; the fifth lens has positive focal power, the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a convex surface; the sixth lens element has negative refractive power, wherein an object-side surface thereof is convex at a paraxial region and an image-side surface thereof is concave at a paraxial region, and at least one of the object-side surface and the image-side surface of the sixth lens element has an inflection point. The optical lens provided by the invention has the advantages of at least large field of view, small distortion, large image plane and large aperture.

Description

Optical lens

Technical Field

The invention relates to the technical field of imaging lenses, in particular to an optical lens.

Background

Currently, with the popularization of portable electronic devices (such as smartphones, tablets and cameras), and the popularity of social, video and live broadcast software, people have a higher and higher preference for photography, and a camera lens has become a standard of the electronic devices, and even has become an index of primary consideration when consumers purchase the electronic devices.

With the continuous development of mobile information technology, portable electronic devices such as mobile phones and the like are also developed towards ultra-wide angle and ultra-high definition imaging, and therefore, higher requirements are put on an imaging lens mounted on the portable electronic devices. Today, cameras with large wide angles have become the standard of flagship machines of all major mobile phone manufacturers so as to meet the shooting requirement of ultra wide angles. The distortion of the large wide-angle lens which is common in the market at present is large, the deformation and stretching of the image are obvious, the proportion is not coordinated, and the distortion needs to be corrected by means of a later software algorithm, so that the problem to be solved is urgent how to realize the balance of the large wide angle, the small distortion, the high pixels and the small volume of the optical lens.

Disclosure of Invention

Therefore, the present invention is directed to an optical lens having at least the advantages of a large wide angle, a small distortion, a large image plane, and a large aperture.

The embodiment of the invention realizes the aim through the following technical scheme.

The invention provides an optical lens, which sequentially comprises from an object side to an image side along an optical axis: a first lens, a second lens, a stop, a third lens, a fourth lens, a fifth lens, and a sixth lens; the first lens has negative focal power, the object side surface of the first lens is concave at a paraxial region, and the image side surface of the first lens is convex at the paraxial region; the second lens has positive focal power, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; the third lens has positive focal power, and the object side surface and the image side surface of the third lens are both convex surfaces; the fourth lens has negative focal power, the object side surface of the fourth lens is concave, and the image side surface of the fourth lens is convex; the fifth lens has positive focal power, the object side surface of the fifth lens is concave, and the image side surface of the fifth lens is convex; the sixth lens element with negative refractive power has a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region, and at least one of the object-side surface and the image-side surface of the sixth lens element has an inflection point; wherein, the optical lens satisfies the conditional expression: 1.8< TTL/f <2.1, TTL represents the total optical length of the optical lens, and f represents the effective focal length of the optical lens.

Compared with the prior art, the optical lens provided by the invention can effectively reduce distortion of an edge view field through reasonable collocation of six lens surfaces and optical power, so that the lens has higher image reduction degree in the whole view field, and can better meet the requirements of wide view field, small distortion and high pixel; meanwhile, the lens has the characteristics of a large aperture and a large image plane, and more luminous flux can enter the lens system, so that the lens can image clearly in a dim environment.

Drawings

The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:

fig. 1 is a schematic structural diagram of an optical lens according to a first embodiment of the present invention.

Fig. 2 is a graph showing a field curvature of an optical lens according to a first embodiment of the present invention.

Fig. 3 is a distortion graph of an optical lens according to a first embodiment of the present invention.

Fig. 4 is an axial chromatic aberration diagram of an optical lens according to a first embodiment of the present invention.

Fig. 5 is a vertical axis chromatic aberration diagram of an optical lens according to a first embodiment of the present invention.

Fig. 6 is a field curvature chart of an optical lens according to a second embodiment of the present invention.

Fig. 7 is a distortion graph of an optical lens according to a second embodiment of the present invention.

Fig. 8 is an axial chromatic aberration diagram of an optical lens according to a second embodiment of the present invention.

Fig. 9 is a vertical axis chromatic aberration diagram of an optical lens according to a second embodiment of the present invention.

Fig. 10 is a field curve diagram of an optical lens according to a third embodiment of the present invention.

Fig. 11 is a distortion graph of an optical lens according to a third embodiment of the present invention.

Fig. 12 is an axial chromatic aberration chart of an optical lens according to a third embodiment of the present invention.

Fig. 13 is a vertical axis chromatic aberration diagram of an optical lens according to a third embodiment of the present invention.

Fig. 14 is a field curve diagram of an optical lens according to a fourth embodiment of the present invention.

Fig. 15 is a distortion graph of an optical lens according to a fourth embodiment of the present invention.

Fig. 16 is an axial chromatic aberration diagram of an optical lens according to a fourth embodiment of the present invention.

Fig. 17 is a vertical axis chromatic aberration diagram of an optical lens according to a fourth embodiment of the present invention.

Detailed Description

In order that the objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Several embodiments of the invention are presented in the figures. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Like reference numerals refer to like elements throughout the specification.

In this context, near the optical axis means the area near the optical axis. If the lens surface is convex and the convex position is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region.

The invention provides an optical lens, which sequentially comprises from an object side to an imaging surface along an optical axis: a first lens, a second lens, a diaphragm, a third lens, a fourth lens, a fifth lens, a sixth lens and an optical filter.

The first lens has negative focal power, the object side surface of the first lens is concave at a paraxial region, and the image side surface of the first lens is convex at the paraxial region.

The second lens has positive focal power, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface.

The third lens has positive focal power, and both the object side surface and the image side surface of the third lens are convex.

The fourth lens has negative focal power, the object side surface of the fourth lens is concave, and the image side surface of the fourth lens is convex.

The fifth lens has positive focal power, the object side surface of the fifth lens is concave, and the image side surface of the fifth lens is convex.

The sixth lens element has negative refractive power with an object-side surface being convex at a paraxial region and an image-side surface being concave at a paraxial region, and at least one of the object-side surface and the image-side surface of the sixth lens element has an inflection point.

In some embodiments, the optical lens satisfies the following conditional expression: 1.8< TTL/f <2.1, wherein TTL represents the total optical length of the optical lens and f represents the effective focal length of the optical lens. The length of the lens can be effectively limited by meeting the above conditions, and the miniaturization of the optical lens can be realized.

In some embodiments, the optical lens satisfies the following conditional expression: 0.97< (f×tan θ)/IH <1.03, where θ represents a maximum half field angle of the optical lens, and IH represents an image height corresponding to the maximum half field angle of the optical lens. The lens has a larger angle of view and smaller distortion, the distortion of the lens can be controlled within +/-2%, and the lens can better meet the requirements of wide view field and small distortion.

In some embodiments, the optical lens satisfies the following conditional expression: -30< f1/f < -8, wherein f1 represents the effective focal length of the first lens. The first lens has proper negative focal power, light rays in a larger range can enter the optical system, the large wide-angle characteristic of the lens is realized, the optical lens can acquire more scene information, the requirement of large-range shooting is met, and meanwhile, the small distortion of the lens is realized.

In some embodiments, the optical lens satisfies the following conditional expression: 1< f3/f <1.5, wherein f3 represents an effective focal length of the third lens. The third lens has proper positive focal power, so that smooth transition of light trend is facilitated, and imaging quality of the optical lens is improved.

In some embodiments, the optical lens satisfies the following conditional expression: -0.01< f3/f2<0.1, wherein f2 represents an effective focal length of the second lens and f3 represents an effective focal length of the third lens. The optical power distribution of the second lens and the third lens is reasonably arranged, so that the converging of marginal view field light rays is facilitated, the converged light rays smoothly enter the rear-end optical system, the smooth transition of the light rays is further realized, the distortion correction difficulty of the marginal view field is reduced, the lens has smaller distortion, and the imaging quality of the optical lens is improved.

In some embodiments, the optical lens satisfies the following conditional expression: -15< f4/f < -4,0< R7/R8<1, wherein f4 represents an effective focal length of the fourth lens, R7 represents a radius of curvature of an object side of the fourth lens, and R8 represents a radius of curvature of an image side of the fourth lens. The above conditions are met, and the distortion of the lens at a large angle of view can be effectively corrected by reasonably setting the focal length and the surface shape of the fourth lens, so that the lens has smaller distortion, and the imaging quality is improved.

In some embodiments, the optical lens satisfies the following conditional expression: 0.5< f5/f <1,2< R9/R10<5, wherein f5 represents an effective focal length of the fifth lens element, R9 represents a radius of curvature of an object-side surface of the fifth lens element, and R10 represents a radius of curvature of an image-side surface of the fifth lens element. The above conditions are satisfied, so that the fifth lens has proper positive focal power and surface shape, the deflection angle of the light passing through the fifth lens can be effectively relaxed, and the tolerance sensitivity and the distortion correction difficulty are reduced.

In some embodiments, the optical lens satisfies the following conditional expression: -2< f6/f < -0.2,2< R11/R12<5, wherein f6 represents an effective focal length of the sixth lens, R11 represents a radius of curvature of an object side of the sixth lens, and R12 represents a radius of curvature of an image side of the sixth lens. The focal length and the surface shape of the sixth lens are reasonably distributed, so that the sixth lens can be better matched with the front five lenses, aberration of the system is better corrected, correction of the aberration is very beneficial, and meanwhile, large-image-plane imaging of the system is also facilitated.

In some embodiments, the optical lens satisfies the following conditional expression: 0.35< R1/R2<1, wherein R1 represents a radius of curvature of an object side surface of the first lens and R2 represents a radius of curvature of an image side surface of the first lens. The system meets the conditions, can effectively balance the aberration and distortion of the edge view field, ensures that the system has a larger view angle and also has better image quality, and reduces the image deformation degree at the edge view field.

In some embodiments, the optical lens satisfies the following conditional expression: 0.9< R3/R4<1.1, wherein R3 represents a radius of curvature of an object side surface of the second lens and R4 represents a radius of curvature of an image side surface of the second lens. The surface shape of the second lens can be reasonably set to ensure that the lens achieves ultra-thin wide angle, and meanwhile, the on-axis aberration is corrected, and the overall imaging quality is improved.

In some embodiments, the optical lens satisfies the following conditional expression: -1.5< R5/R6< -0.8, wherein R5 represents a radius of curvature of an object-side surface of the third lens and R6 represents a radius of curvature of an image-side surface of the third lens. The surface shape of the third lens can be reasonably set to meet the conditions, so that the forming of the third lens is facilitated, the large aperture characteristic of the lens can be better realized, the problem that the relative brightness of the edge view field brought by a wide angle is fast to drop is solved, and more scene information is also facilitated to be acquired.

In some embodiments, the optical lens satisfies the following conditional expression: 1.35< TTL/IH <1.55, wherein IH represents the image height corresponding to the maximum half field angle of the optical lens. The lens has the advantages that the lens can be ultrathin, meanwhile, the lens has a larger image surface, chips with larger sizes can be matched, and high-definition imaging of the system in a wide-angle range is realized.

In some embodiments, the optical lens satisfies the following conditional expression: 20< f45/CT45<40, wherein f45 denotes a combined focal length of the fourth lens and the fifth lens, and CT45 denotes a separation distance of the fourth lens and the fifth lens on an optical axis. The conditions are met, and the relation between the combined focal length of the fourth lens and the fifth lens and the air interval is reasonably controlled, so that the distortion of an optical system can be effectively reduced, and the shooting effect of the lens at a large view field is improved.

In some embodiments, the optical lens satisfies the following conditional expression: 5<f/CT1<8, where f represents the effective focal length of the optical lens and CT1 represents the center thickness of the first lens. The conditions are met, the vertical axis chromatic aberration of the optical system can be reduced by controlling the ratio of f/CT1, and the imaging quality of the lens is improved.

In some embodiments, the optical lens satisfies the following conditional expression: 0.05< | (f5+f6)/(f 5-f 6) | <0.5, wherein f5 represents an effective focal length of the fifth lens and f6 represents an effective focal length of the sixth lens. Satisfying the above condition can make the optical system improve the resolution with less optical distortion.

In some embodiments, the optical lens satisfies the following conditional expression: 0.15< (CT 4+ CT 5)/TTL <0.25, wherein CT4 represents a center thickness of the fourth lens, CT5 represents a center thickness of the fifth lens, and TTL represents an optical total length of the optical lens. The lens has a larger field angle, can effectively reduce the correction difficulty of chromatic aberration and provides the imaging quality of the lens.

In some embodiments, the optical lens satisfies the following conditional expression: 0.2< (CT1+CT2+CT3)/TTL <0.3, wherein CT1 represents the center thickness of the first lens, CT2 represents the center thickness of the second lens, CT3 represents the center thickness of the third lens, and TTL represents the total optical length of the optical lens. The central thickness of the front three lenses is reasonably set to enable the optical distortion of the optical lens to be well corrected, and meanwhile the sensitivity of the optical lens is reduced and the resolution capability is improved.

In some embodiments, the optical lens satisfies the following conditional expression: -15< (f4+f5+f6)/f < -3, wherein f4 represents an effective focal length of the fourth lens, f5 represents an effective focal length of the fifth lens, f6 represents an effective focal length of the sixth lens, and f represents an effective focal length of the optical lens. The lens has the advantages that the focal power of the three lenses is reasonably configured, so that the coma correction of the off-axis visual field is enhanced, and meanwhile, the curvature and the aberration are well converged, so that the lens has higher resolving power.

In the application, the optical lens can adopt a glass lens and a plastic lens for matching, and can also adopt a full plastic lens structure; in order to realize wide angle and small distortion of the lens, the lens can also be ensured to have good imaging effect, the first lens, the second lens, the fourth lens, the fifth lens and the sixth lens in the optical lens are all plastic aspheric lenses, the third lens can be plastic aspheric lenses or glass aspheric lenses, and the glass-plastic mixed materials are adopted for matching, so that the cost can be effectively reduced, aberration can be corrected, and an optical performance product with higher cost performance is provided.

The invention is further illustrated in the following examples. In various embodiments, the thickness, radius of curvature, and material selection portion of each lens in the optical lens may vary, and for specific differences, reference may be made to the parameter tables of the various embodiments. The following examples are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following examples, and any other changes, substitutions, combinations or simplifications that do not depart from the gist of the present invention are intended to be equivalent substitutes within the scope of the present invention.

In various embodiments of the present invention, the aspherical profile of each lens satisfies the following equation:

；

where z is the distance sagittal height from the aspherical surface vertex when the aspherical surface is at a position of height h in the optical axis direction, c is the paraxial curvature of the surface, k is the quadric coefficient, A _2i The aspherical surface profile coefficient of the 2 i-th order.

First embodiment

Referring to fig. 1, a schematic structural diagram of an optical lens 100 according to a first embodiment of the present invention is shown, where the optical lens 100 includes, in order from an object side to an imaging surface S15 along an optical axis: a first lens L1, a second lens L2, a stop ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a filter G1.

The first lens element L1 has negative refractive power, wherein an object-side surface S1 of the first lens element is concave at a paraxial region thereof, and an image-side surface S2 of the first lens element is convex at a paraxial region thereof.

The second lens element L2 has positive refractive power, wherein an object-side surface S3 of the second lens element is convex, and an image-side surface S4 of the second lens element is concave.

The third lens element L3 has positive refractive power, wherein an object-side surface S5 of the third lens element is convex, and an image-side surface S6 of the third lens element is convex.

The fourth lens element L4 has negative refractive power, wherein an object-side surface S7 of the fourth lens element is concave, and an image-side surface S8 of the fourth lens element is convex.

The fifth lens element L5 has positive refractive power, wherein an object-side surface S9 of the fifth lens element is concave, and an image-side surface S10 of the fifth lens element is convex.

The sixth lens element L6 has negative refractive power, wherein an object-side surface S11 of the sixth lens element is convex at a paraxial region thereof and an image-side surface S12 of the sixth lens element is concave at a paraxial region thereof.

The object side surface of the filter G1 is S13, and the image side surface is S14.

The first lens L1, the second lens L2, the fourth lens L4, the fifth lens L5 and the sixth lens L6 are all plastic aspherical lenses, and the third lens L3 is a glass aspherical lens.

The relevant parameters of each lens in the optical lens 100 provided in this embodiment are shown in table 1.

TABLE 1

The surface profile coefficients of the aspherical surfaces of the optical lens 100 in this embodiment are shown in table 2.

TABLE 2

Referring to fig. 2 to 5, a field curvature curve graph, a distortion curve graph, an axial chromatic aberration curve graph, and a vertical chromatic aberration curve graph of the optical lens 100 are shown.

The field curvature curve of fig. 2 shows the degree of curvature of the meridional image plane and the sagittal image plane, and in the figure, the horizontal axis shows the amount of shift (in mm) and the vertical axis shows the angle of view (in degrees). As can be seen from the figure, the curvature of field of the meridional image plane and the sagittal image plane are controlled within ±0.3 mm, which indicates that the curvature of field of the optical lens 100 is well corrected.

The distortion curves of fig. 3 represent distortion at different image heights on the imaging plane, with the horizontal axis representing the percent distortion and the vertical axis representing the angle of view (in degrees). As can be seen from the figure, the optical distortion at different image heights on the imaging plane is controlled within ±1.0%, which means that the optical distortion of the optical lens 100 is well corrected.

The axial chromatic aberration curve of fig. 4 represents aberration on the optical axis at the imaging plane, in which the horizontal axis represents a sphere value (unit: mm) and the vertical axis represents a normalized pupil radius. As can be seen from the figure, the axial chromatic aberration is controlled within ±0.025mm, which means that the axial chromatic aberration of the optical lens 100 is well corrected.

The vertical axis color difference curve of fig. 5 shows the color difference between the longest wavelength and the shortest wavelength at different image heights on the imaging plane, in which the horizontal axis shows the vertical axis color difference value (unit: micrometers) of each wavelength with respect to the center wavelength, and the vertical axis shows the normalized field angle. As can be seen from the figure, the vertical chromatic aberration of each wavelength with respect to the center wavelength in different fields of view is controlled within ±2.5 microns, indicating that the vertical chromatic aberration of the optical lens 100 is well corrected.

Second embodiment

The optical lens provided in this embodiment is substantially identical to the optical lens 100 in the first embodiment in structure, and differs mainly in that: the radius of curvature, aspherical coefficient, thickness, and the like of each lens surface are different.

The relevant parameters of each lens in the optical lens provided in this embodiment are shown in table 3.

TABLE 3 Table 3

The surface form coefficients of the aspherical surfaces of the optical lens in this example are shown in table 4.

TABLE 4 Table 4

Referring to fig. 6 to 9, a field curvature curve graph, a distortion curve graph, an axial chromatic aberration curve graph, and a vertical chromatic aberration curve graph of the optical lens in the present embodiment are shown.

The curvature of field curve of fig. 6 shows the curvature of meridian image plane and sagittal image plane, and it can be seen from the figure that the curvature of field of meridian image plane and sagittal image plane is controlled within ±0.15 mm, which indicates that the curvature of field of the optical lens is well corrected.

The distortion curves of fig. 7 show distortions at different image heights on the imaging plane, and it can be seen from the graph that the optical distortions at different image heights on the imaging plane are controlled within ±1.6%, which indicates that the optical distortions of the optical lens are well corrected.

The axial chromatic aberration curve of fig. 8 shows the aberration on the optical axis at the imaging surface, and it can be seen from the graph that the offset of the axial chromatic aberration is controlled within ±0.025mm, which indicates that the axial chromatic aberration of the optical lens is well corrected.

The vertical axis chromatic aberration curve of fig. 9 shows chromatic aberration of the longest wavelength and the shortest wavelength at different image heights on the imaging plane, and it can be seen from the graph that vertical axis chromatic aberration of each wavelength relative to the center wavelength in different fields of view is controlled within ±3.5 microns, which indicates that vertical axis chromatic aberration of the optical lens is well corrected.

Third embodiment

The optical lens provided in this embodiment is substantially identical to the optical lens 100 in the first embodiment in structure, and differs mainly in that: the third lens L3 is a plastic aspherical lens, and the curvature radius, aspherical coefficient, thickness, etc. of each lens surface are different.

The relevant parameters of each lens in the optical lens provided in this embodiment are shown in table 5.

TABLE 5

The surface form coefficients of the aspherical surfaces of the optical lens in this example are shown in table 6.

TABLE 6

Referring to fig. 10 to 13, a field curvature curve graph, a distortion curve graph, an axial chromatic aberration curve graph, and a vertical chromatic aberration curve graph of the optical lens in the present embodiment are shown.

The curvature of field curve of fig. 10 shows the curvature of meridian image plane and sagittal image plane, and it can be seen from the figure that the curvature of field of meridian image plane and sagittal image plane is controlled within ±0.1 mm, which indicates that the curvature of field of the optical lens is well corrected.

The distortion curves of fig. 11 show distortions at different image heights on the imaging plane, and it can be seen from the graph that the optical distortions at different image heights on the imaging plane are controlled within ±0.8%, which indicates that the optical distortions of the optical lens are well corrected.

The axial chromatic aberration curve of fig. 12 shows the aberration on the optical axis at the imaging surface, and it can be seen from the graph that the offset of the axial chromatic aberration is controlled within ±0.035mm, which indicates that the axial chromatic aberration of the optical lens is well corrected.

The vertical axis chromatic aberration curve of fig. 13 shows chromatic aberration of the longest wavelength and the shortest wavelength at different image heights on the imaging plane, and it can be seen from the figure that vertical axis chromatic aberration of each wavelength in different fields of view is controlled within ±3 micrometers with respect to the center wavelength, which indicates that vertical axis chromatic aberration of the optical lens is well corrected.

Fourth embodiment

The relevant parameters of each lens in the optical lens in this embodiment are shown in table 7.

TABLE 7

The surface form coefficients of the aspherical surfaces of the optical lens in this example are shown in table 8.

TABLE 8

Referring to fig. 14 to 17, a field curvature curve graph, a distortion curve graph, an axial chromatic aberration curve graph, and a vertical chromatic aberration curve graph of the optical lens in the present embodiment are shown.

The curvature of field curve of fig. 14 shows the curvature of meridian image plane and sagittal image plane, and it can be seen from the figure that the curvature of field of meridian image plane and sagittal image plane is controlled within ±0.15 mm, which indicates that the curvature of field of the optical lens is well corrected.

The distortion curves of fig. 15 show distortions at different image heights on the imaging plane, and it can be seen from the graph that the optical distortions at different image heights on the imaging plane are controlled within ±1.2%, which indicates that the optical distortions of the optical lens are well corrected.

The axial chromatic aberration curve of fig. 16 shows the aberration on the optical axis at the imaging surface, and it can be seen from the graph that the offset of the axial chromatic aberration is controlled within ±0.045mm, which indicates that the axial chromatic aberration of the optical lens is well corrected.

The vertical axis chromatic aberration curve of fig. 17 shows chromatic aberration of the longest wavelength and the shortest wavelength at different image heights on the imaging plane, and it can be seen from the figure that vertical axis chromatic aberration of each wavelength relative to the center wavelength in different fields of view is controlled within ±3.5 micrometers, which indicates that vertical axis chromatic aberration of the optical lens is well corrected.

Table 9 is an optical characteristic corresponding to the above four embodiments, and mainly includes an effective focal length F, an optical total length TTL, an aperture f#, a field angle FOV, an image height IH corresponding to a maximum half field angle, and a numerical value corresponding to each of the above conditional expressions.

TABLE 9

In summary, the optical lens provided by the embodiment of the invention has at least the following advantages:

(1) The optical distortion of the wide-angle lens commonly seen in the market is generally more than 30%, and the optical lens provided by the invention has larger field angle and smaller distortion due to reasonable arrangement of the lens surfaces and optical power, so that the distortion of the lens can be controlled within +/-2%, and the requirements of wide field of view, small distortion and high pixel can be better met.

(2) The optical lens provided by the invention has reasonable lens shape and aperture position arrangement, is beneficial to enlarging the field angle of the optical lens and realizing the large aperture characteristic of the lens, the wide-angle characteristic is beneficial to the optical lens to acquire more scene information, the requirement of large-range shooting is met, and the large aperture characteristic is beneficial to improving the problem of rapid relative brightness decline of the edge view field caused by wide angle, thereby being beneficial to acquiring more scene information.

(3) The optical lens provided by the invention has a larger imaging surface, can be matched with a chip with a larger size, and realizes high-definition imaging of the system in a wide-angle range.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means 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 present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. 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 invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. An optical lens comprising, in order from an object side to an image side along an optical axis: a first lens, a second lens, a stop, a third lens, a fourth lens, a fifth lens, and a sixth lens;

the first lens has negative focal power, the object side surface of the first lens is concave at a paraxial region, and the image side surface of the first lens is convex at the paraxial region;

the second lens has positive focal power, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface;

the third lens has positive focal power, and the object side surface and the image side surface of the third lens are both convex surfaces;

the fourth lens has negative focal power, the object side surface of the fourth lens is concave, and the image side surface of the fourth lens is convex;

the fifth lens has positive focal power, the object side surface of the fifth lens is concave, and the image side surface of the fifth lens is convex;

the sixth lens element with negative refractive power has a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region, and at least one of the object-side surface and the image-side surface of the sixth lens element has an inflection point;

wherein, the optical lens satisfies the conditional expression: 1.8< TTL/f <2.1, TTL represents the total optical length of the optical lens, and f represents the effective focal length of the optical lens.

2. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.97< (f×tan θ)/IH <1.03, where θ represents a maximum half field angle of the optical lens, and IH represents an image height corresponding to the maximum half field angle of the optical lens.

3. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: -30< f1/f < -8, wherein f1 represents the effective focal length of the first lens.

4. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 1< f3/f <1.5, wherein f3 represents an effective focal length of the third lens.

5. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: -0.01< f3/f2<0.1, wherein f2 represents an effective focal length of the second lens and f3 represents an effective focal length of the third lens.

6. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: -15< f4/f < -4,0< R7/R8<1, wherein f4 represents an effective focal length of the fourth lens, R7 represents a radius of curvature of an object side of the fourth lens, and R8 represents a radius of curvature of an image side of the fourth lens.

7. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.5< f5/f <1,2< R9/R10<5, wherein f5 represents an effective focal length of the fifth lens element, R9 represents a radius of curvature of an object-side surface of the fifth lens element, and R10 represents a radius of curvature of an image-side surface of the fifth lens element.

8. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: -2< f6/f < -0.2,2< R11/R12<5, wherein f6 represents an effective focal length of the sixth lens, R11 represents a radius of curvature of an object side of the sixth lens, and R12 represents a radius of curvature of an image side of the sixth lens.

9. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.35< R1/R2<1, wherein R1 represents a radius of curvature of an object side surface of the first lens and R2 represents a radius of curvature of an image side surface of the first lens.

10. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.9< R3/R4<1.1, wherein R3 represents a radius of curvature of an object side surface of the second lens and R4 represents a radius of curvature of an image side surface of the second lens.

11. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: -1.5< R5/R6< -0.8, wherein R5 represents a radius of curvature of an object-side surface of the third lens and R6 represents a radius of curvature of an image-side surface of the third lens.

12. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 1.35< TTL/IH <1.55, wherein IH represents the image height corresponding to the maximum half field angle of the optical lens.