CN114002824A

CN114002824A - Optical imaging lens and imaging apparatus

Info

Publication number: CN114002824A
Application number: CN202111594516.XA
Authority: CN
Inventors: 陈伟建; 王家贤
Original assignee: Jiangxi Lianchuang Electronic Co Ltd
Current assignee: Hefei Lianchuang Optical Co ltd
Priority date: 2021-12-24
Filing date: 2021-12-24
Publication date: 2022-02-01
Anticipated expiration: 2041-12-24
Also published as: CN114002824B

Abstract

The invention discloses an optical imaging lens and imaging equipment, the optical imaging lens comprises the following components in sequence from an object side to an imaging surface along an optical axis: a first group having negative optical power, a second group having positive optical power, a third group having optical power; the first group includes in order from the object side to the imaging surface along the optical axis: a first lens having a negative power, a second lens having a negative power; the second group comprises in order from the object side to the imaging surface along the optical axis: the third lens with positive focal power, the fourth lens with positive focal power, the fifth lens with negative focal power, and the fourth lens and the fifth lens form a cemented lens; the third group includes, in order from the object side to the image plane along the optical axis: a sixth lens having optical power. The optical imaging lens has the advantages of large aperture, long focal length and small aperture, can provide high-definition imaging effect, and can improve the imaging quality and identification accuracy of a long-distance target.

Description

Optical imaging lens and imaging apparatus

Technical Field

The present invention relates to the field of imaging lens technology, and in particular, to an optical imaging lens and an imaging device.

Background

With the development of automatic driving technology, ADAS (Advanced Driver assistance System) has become a standard configuration for many automobiles; the vehicle-mounted camera lens is used as a key device of the ADAS, can sense the road conditions around the vehicle in real time, realizes the functions of forward collision early warning, lane deviation warning, pedestrian detection and the like, and directly influences the safety coefficient of the ADAS due to the performance of the vehicle-mounted camera lens, so that the performance requirement on the vehicle-mounted camera lens is higher and higher.

The optical lens carried in the ADAS and applied to the front of the vehicle mainly identifies the front condition of the vehicle, requires the barrier to be clearly distinguished at a long distance and realizes collision early warning. At present, an optical lens for identifying a target in front of a vehicle is usually designed for a short-distance target, the field angle of the optical lens is relatively large, although the optical lens can better image the short-distance target, the imaging effect on the long-distance target is poor, the identification accuracy rate of the long-distance target and the medium-distance target cannot be considered, the effective target identification range is reduced, and the requirement of the vehicle on the front pre-aiming distance during running at a high speed is difficult to meet.

Disclosure of Invention

Therefore, the present invention is directed to an optical imaging lens and an imaging device, which have the advantages of a large aperture, a long focal length, and a small aperture, and at the same time, provide a high-definition imaging effect, and improve the imaging quality and recognition accuracy for a long-distance target.

The embodiment of the invention implements the above object by the following technical scheme.

In a first aspect, the present invention provides an optical imaging lens, comprising, in order from an object side to an imaging plane along an optical axis: a first group having negative optical power, a second group having positive optical power, a third group having optical power; the first group sequentially includes from an object side to an imaging surface along an optical axis: the lens comprises a first lens with negative focal power, a second lens and a third lens, wherein the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; the second lens is provided with negative focal power, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface; the second group comprises, in order from the object side to the image plane along the optical axis: the image side surface of the third lens is a convex surface; the fourth lens is provided with positive focal power, and the object side surface and the image side surface of the fourth lens are convex surfaces; the fourth lens and the fifth lens form a cemented lens; the third group comprises, in order from the object side to the image plane along the optical axis: a sixth lens having a optical power, an object-side surface of the sixth lens being convex at a paraxial region, an image-side surface of the sixth lens being concave at a paraxial region; and a diaphragm is arranged between the first lens and the second lens, and the optical imaging lens comprises at least one aspheric lens.

In a second aspect, the present invention provides an imaging apparatus, including an imaging element and the optical imaging lens provided in the first aspect, wherein the imaging element is configured to convert an optical image formed by the optical imaging lens into an electrical signal.

Compared with the prior art, the optical imaging lens and the imaging equipment provided by the invention have the advantages that six lenses are adopted, and the lens has good thermal stability and can realize clear imaging through reasonable control of various surface types and reasonable combination of materials and focal power; the long-focus-distance-based high-precision long-distance target identification method has the advantages that the long focus distance is met, the field angle of the lens can be increased as much as possible, the imaging performance of the lens in a long-distance view is improved, and therefore the imaging quality and the identification accuracy of a long-distance target are improved.

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 structural diagram of an optical imaging lens according to a first embodiment of the present invention;

FIG. 2 is a distortion curve diagram of an optical imaging lens according to a first embodiment of the present invention;

FIG. 3 is an MTF chart of an optical imaging lens according to a first embodiment of the present invention;

FIG. 4 is a graph illustrating axial chromatic aberration of an optical imaging lens according to a first embodiment of the present invention;

FIG. 5 is a schematic structural diagram of an optical imaging lens according to a second embodiment of the present invention;

FIG. 6 is a distortion curve diagram of an optical imaging lens according to a second embodiment of the present invention;

FIG. 7 is an MTF chart of an optical imaging lens according to a second embodiment of the present invention;

FIG. 8 is a graph of axial chromatic aberration of an optical imaging lens according to a second embodiment of the present invention;

FIG. 9 is a schematic structural diagram of an optical imaging lens system according to a third embodiment of the present invention;

fig. 10 is a distortion graph of an optical imaging lens according to a third embodiment of the present invention;

FIG. 11 is a MTF chart of an optical imaging lens according to a third embodiment of the present invention;

FIG. 12 is a graph illustrating axial chromatic aberration of an optical imaging lens according to a third embodiment of the present invention;

FIG. 13 is a schematic structural diagram of an optical imaging lens system according to a fourth embodiment of the present invention;

fig. 14 is a distortion graph of an optical imaging lens according to a fourth embodiment of the present invention;

fig. 15 is an MTF chart of an optical imaging lens according to a fourth embodiment of the present invention;

FIG. 16 is a graph illustrating axial chromatic aberration of an optical imaging lens according to a fourth embodiment of the present invention;

fig. 17 is a schematic configuration diagram of an image forming apparatus according to a fifth embodiment of the present invention.

Detailed Description

In order to make the objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. Several embodiments of the invention are presented in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

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.

The invention provides an optical imaging lens, which sequentially comprises the following components from an object side to an imaging surface along an optical axis: a first group having negative optical power, a second group having positive optical power, and a third group having optical power.

Wherein the first group comprises, in order from an object side to an image plane along an optical axis:

the lens comprises a first lens with negative focal power, a second lens and a third lens, wherein the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface;

the second lens with negative focal power is characterized in that the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface.

The second group comprises, in order from the object side to the image plane along the optical axis:

the image side surface of the third lens is a convex surface;

the fourth lens is provided with positive focal power, and the object side surface and the image side surface of the fourth lens are convex surfaces;

and the fourth lens and the fifth lens form a cemented lens.

The third group comprises, in order from the object side to the image plane along the optical axis:

a sixth lens having a power, an object side surface of the sixth lens being convex at a paraxial region, an image side surface of the sixth lens being concave at a paraxial region.

And a diaphragm is arranged between the first lens and the second lens, and the optical imaging lens comprises at least one aspheric lens.

In order to realize better imaging quality, the first lens in the optical imaging lens adopts an aspheric lens, and the aspheric lens has the characteristic that the curvature of the lens from the center to the periphery is continuously changed, so that the optical imaging lens has the advantages of improving the distortion aberration and the astigmatic aberration. Therefore, the first lens uses an aspheric surface to improve the imaging quality and reduce the distortion. The object side of the first lens is a convex surface, so that large-field light can be collected as far as possible to enter the rear optical system, the light flux is increased, the whole large-field range is realized, the collected light can be compressed, and the light can be stably transited to the rear optical system.

The second lens in the optical imaging lens is a glass spherical lens or an aspheric lens, and the second lens is a meniscus lens which is convex towards the image side, so that light can be further diffused to enter a rear optical system, and the light flux of the system is increased; and effectively compensates for spherical aberration introduced by the first lens.

The third lens in the optical imaging lens is a glass spherical lens, the object side surface of the third lens can be a convex surface or a concave surface, and the image side surface is a convex surface. The third lens has positive focal power, is beneficial to converging light rays, enables the diverging light rays to smoothly enter a rear optical system after being converged, and is beneficial to realizing the miniaturization of the system; the spherical aberration introduced by the front lens can be balanced, and the integral imaging quality of the lens is improved.

And a fourth lens and a fifth lens in the optical imaging lens form a cemented lens. Cemented lenses are used to minimize or eliminate chromatic aberration. The use of the cemented lens can improve the image quality and reduce the reflection loss of light energy, thereby improving the definition of the image. The cemented lens consisting of the fourth positive lens and the fifth negative lens is introduced in the application, so that the chromatic aberration influence can be eliminated, and the tolerance sensitivity of the system is reduced; the fourth lens and the fifth lens which are simultaneously cemented can also leave partial chromatic aberration to balance the overall chromatic aberration of the optical system. In addition, the use of the cemented lens composed of the fourth lens and the fifth lens can also simplify the assembly procedure in the lens manufacturing process, facilitating the mass production of the lens.

The sixth lens in the optical imaging lens can have negative focal power or positive focal power, and the sixth lens uses an aspheric lens, so that the incident angle of a chief ray can be well controlled, and the edge resolution and spherical aberration correction can be improved.

In some embodiments, the optical imaging lens satisfies the conditional expression:

-3<F1/f<-1；（1）

-3<F1/F2<-1；（2）

-0.5<F2/F3<1；（3）

wherein F1 represents the effective focal length of the first group, F2 represents the effective focal length of the second group, F3 represents the effective focal length of the third group, and F represents the effective focal length of the optical imaging lens. Satisfying the conditional expressions (1) and (3) helps to converge light and ensure the light flux of the system. The optical lens meets the conditional expression (2), can better collect light, reduce the caliber and the size of the rear end of the optical lens, and better correct spherical aberration and chromatic dispersion brought by the first group.

0.37<f/TTL<0.39；（4）

0.015/°<D1/IH/FOV<0.025/°；（5）

wherein, TTL represents the total optical length of the optical imaging lens, f represents the effective focal length of the optical imaging lens, D1 represents the effective aperture of the object-side surface of the first lens, FOV represents the maximum field angle of the optical imaging lens, and IH represents the image height corresponding to the half field angle of the optical imaging lens. The conditional expressions (4) and (5) are met, the shooting capability of the lens to a long shot is improved by controlling the ratio of the effective focal length to the total length of the system, the ratio of the aperture, the image height and the field angle is controlled, the field angle and the image surface size of the lens can be improved as much as possible while the lens is kept to have a smaller aperture, and the imaging quality and the identification accuracy of a far-range image can be improved.

In some embodiments, the first lens is an aspheric lens and the first lens satisfies the conditional expression:

1.0<R1/R2<1.6；（6）

1<f1/F1<5；（7）

where R1 denotes a radius of curvature of an object-side surface of the first lens, R2 denotes a radius of curvature of an image-side surface of the first lens, F1 denotes an effective focal length of the first lens, and F1 denotes an effective focal length of the first group. The optical lens meets the conditional expressions (6) and (7), and by controlling the surface type of the first lens and fully utilizing the characteristics of the aspheric lens, the light inlet quantity is increased, the generation of spherical aberration is reduced, the difficulty of correcting the aberration of the follow-up lens is reduced, the distortion of the system is effectively reduced, and the integral imaging quality is improved.

0.97<Vd4/Vd5<1；（8）

wherein Vd4 denotes a material refractive index of the fourth lens, and Vd5 denotes a material refractive index of the fifth lens. The fourth lens and the fifth lens form a cemented lens, the conditional expression (8) is satisfied, the refractive index difference of the cemented lens is controlled, and chromatic aberration can be reduced or eliminated to the maximum extent.

0<|CT56/f6|<0.1；（9）

0.2mm/°<IH/CRA<0.4mm/°；（10）

wherein CT56 denotes an air space on the optical axis between the fifth lens and the sixth lens, f6 denotes an effective focal length of the sixth lens, IH denotes an image height corresponding to a half field angle of the optical imaging lens, and CRA denotes a chief ray incident angle corresponding to a maximum field angle of the optical imaging lens. The condition formulas (9) and (10) are met, so that the lens has the characteristic of longer back focus on the basis of realizing system miniaturization, the assembly interference between the lens and an imaging chip is reduced, and the back focus is beneficial to reducing CRA (CRA) at the same time; in addition, the total length of the lens is short, the structure is compact, the sensitivity of the lens to the Modulation Transfer Function (MTF) is reduced, the production yield is improved, and the production cost is reduced.

5.0<TTL/D1<7.5；（11）

F#<1.7；（12）

wherein, TTL represents the optical total length of the optical imaging lens, D1 represents the effective aperture of the object side surface of the first lens, and F # represents the diaphragm number of the optical imaging lens. The requirements of the conditional expressions (11) and (12) are met, so that the front end of the lens has a smaller caliber, and the miniaturization of the lens is better realized; meanwhile, the lens has the characteristic of large aperture, so that the light entering amount of the lens is large, and the imaging requirement under the light and dark environment can be met.

2.0<f/IH<2.8；（13）

wherein f represents the effective focal length of the optical imaging lens, and IH represents the image height corresponding to the half field angle of the optical imaging lens. Satisfying the above conditional expression (13), it indicates that the lens has a longer effective focal length and a larger image plane, and can realize high-definition imaging of a far-range image.

0.75<D1/D5<0.95；（14）

where D1 denotes the effective aperture of the object-side surface of the first lens, and D5 denotes the effective aperture of the object-side surface of the third lens. The condition (14) is satisfied, so that the aperture of the first lens is smaller than that of the third lens, the front end aperture of the lens is reduced, and miniaturization is realized.

|DIS|<10%；（15）

wherein DIS represents optical distortion of the optical imaging lens. The condition expression (15) is satisfied, so that the size of the field of view of the lens can be improved as much as possible, and the imaging quality is further improved.

In some embodiments, the sixth lens has positive optical power, and the effective focal length f6 of the sixth lens and the effective focal length f of the optical imaging lens satisfy: 1< f6/f < 5. In other embodiments, the sixth lens may also have a negative power, and the effective focal length f6 of the sixth lens and the effective focal length f of the optical imaging lens satisfy: -10< f6/f < -5. The sixth lens adopts positive focal power or negative focal power, so that the system has a good imaging effect, and is specifically determined by combining and matching with other lenses.

The invention is further illustrated below in the following examples. In each embodiment, the thickness, the curvature radius, and the material selection part of each lens in the optical imaging lens are different, and the specific difference can be referred to the parameter table of each embodiment. The following examples are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following examples, and any other changes, substitutions, combinations or simplifications which do not depart from the innovative points of the present invention should be construed as being equivalent substitutions and shall be included within the scope of the present invention.

In the embodiments of the present invention, when the lenses in the optical imaging lens are aspheric lenses, each aspheric surface type satisfies the following equation:

wherein z represents the distance in the optical axis direction from the curved surface vertex, c represents the curvature of the curved surface vertex, K represents the conic coefficient, h represents the distance from the optical axis to the curved surface, and B, C, D, E, F, G, H represents the curved surface coefficients of fourth order, sixth order, eighth order, tenth order, twelfth order, fourteenth order, and sixteenth order, respectively.

First embodiment

Referring to fig. 1, a schematic structural diagram of an optical imaging lens 100 according to a first embodiment of the present invention is shown, where the optical imaging lens 100 sequentially includes, from an object side to an image plane along an optical axis: a first group Q1 with negative optical power, a second group Q2 with positive optical power, a third group Q3 with positive optical power, and a filter G1.

The first group Q1 includes, in order from the object side to the image plane along the optical axis: a first lens L1 and a second lens L2. The second group Q2 includes, in order from the object side to the image plane along the optical axis: a third lens L3, a fourth lens L4, and a fifth lens L5. The third group Q3 includes, in order from the object side to the image plane along the optical axis: and a sixth lens L6. A stop ST is provided between the first lens L1 and the second lens L2.

The first lens element L1 has negative power, the object-side surface S1 of the first lens element is convex, and the image-side surface S2 of the first lens element is concave;

the second lens L2 has negative power, the object side S3 of the second lens is concave, and the side S4 of the second lens is convex;

the third lens L3 has positive optical power, and both the object-side surface S5 and the image-side surface S6 of the third lens are convex;

the fourth lens L4 has positive focal power, and both the object-side surface S7 and the image-side surface of the fourth lens are convex;

the fifth lens L5 has negative focal power, the object side surface and the image side surface S9 of the fifth lens are both concave surfaces, the fourth lens L4 and the fifth lens L5 form a cemented lens group, and the image side surface of the fourth lens L4 and the object side surface of the fifth lens L5 are cemented to form a cemented surface S8;

the sixth lens element L6 has positive optical power, an object-side surface S10 of the sixth lens element being convex at a paraxial region and concave at a distance from the optical axis, and an image-side surface S11 of the sixth lens element being concave at a paraxial region and convex at a distance from the optical axis.

The first lens L1 and the sixth lens L6 are both glass aspheric lenses; the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are all glass spherical lenses, and the optical centers of the lenses are all located on the same straight line.

The parameters related to each lens in the optical imaging lens 100 provided in this embodiment are shown in table 1.

TABLE 1

The surface shape coefficients of the aspherical surfaces of the optical imaging lens 100 in the present embodiment are shown in table 2.

TABLE 2

The distortion graph, the MTF graph and the axial chromatic aberration graph of the optical imaging lens 100 provided in the present embodiment are respectively shown in fig. 2, fig. 3 and fig. 4. As can be seen from fig. 2, the distortion of the optical imaging lens 100 in the present embodiment is entirely within a range of-10%, which illustrates that the optical imaging lens has small distortion; as can be seen from FIG. 3, the MTF value is greater than 0.45 under the condition of 83lp/mm, which indicates that the imaging quality of the optical imaging lens is good, and as can be seen from FIG. 4, the axial chromatic aberration is between-0.01 mm and 0.04mm, which indicates that the optical imaging lens 100 has good achromatism performance.

Second embodiment

Referring to fig. 5, a schematic structural diagram of an optical imaging lens 200 according to an embodiment of the present invention is shown, where the structure of the optical imaging lens 200 in the embodiment is substantially the same as that of the optical imaging lens 100 in the first embodiment, and the difference is that: the object-side surface S10 of the sixth lens element is convex, and the image-side surface S11 is concave; the mechanical back focus between the sixth lens L6 of the last lens and the imaging surface S14 is lengthened; and the material of partial lens, the relevant parameter of each lens and the air space have difference.

Table 3 shows the parameters related to each lens of the optical imaging lens 200 according to the present embodiment.

TABLE 3

The surface shape coefficients of the aspherical surfaces in the optical imaging lens 200 in the present embodiment are shown in table 4.

TABLE 4

The distortion graph, the MTF graph and the axial chromatic aberration graph of the optical imaging lens 200 provided in the present embodiment are respectively shown in fig. 6, fig. 7 and fig. 8. As can be seen from fig. 6, the distortion of the optical imaging lens 200 in the present embodiment is entirely within a range of-10%, which illustrates that the optical imaging lens has small distortion; as can be seen from FIG. 7, the MTF value is greater than 0.55 under the condition of 83Lp/mm, which indicates that the imaging quality of the optical imaging lens is good, and as can be seen from FIG. 8, the axial chromatic aberration is between-0.01 mm and 0.03mm, which indicates that the optical imaging lens 200 has good achromatism performance.

Third embodiment

Referring to fig. 9, a schematic structural diagram of an optical imaging lens 300 according to an embodiment of the present invention is shown, where the structure of the optical imaging lens 300 in the present embodiment is substantially the same as that of the optical imaging lens 100 in the first embodiment, and the difference is that: the second lens L2 is an aspheric lens, the sixth lens L6 is a negative power lens, and the parameters and air space of the lenses are different.

Table 5 shows the parameters related to each lens of the optical imaging lens 300 according to the present embodiment.

TABLE 5

The surface shape coefficients of the aspherical surfaces of the optical imaging lens 300 in this embodiment are shown in table 6.

TABLE 6

The distortion graph, MTF graph and axial chromatic aberration graph of the optical imaging lens 300 provided in the present embodiment are respectively shown in fig. 10, fig. 11 and fig. 12. As can be seen from fig. 10, the distortion of the optical imaging lens 300 in the present embodiment is entirely within a range of-10%, which illustrates that the optical imaging lens has small distortion; as can be seen from FIG. 11, the MTF value is greater than 0.55 under the condition of 83Lp/mm, which indicates that the imaging quality of the optical imaging lens is good, and as can be seen from FIG. 12, the axial chromatic aberration is between-0.04 mm and 0.04mm, which indicates that the optical imaging lens 300 has good achromatism performance.

Fourth embodiment

Referring to fig. 9, a schematic structural diagram of an optical imaging lens 400 according to an embodiment of the present invention is shown, where the structure of the optical imaging lens 400 in the embodiment is substantially the same as that of the wide-angle lens 100 in the first embodiment, and the difference is that: the object side surface S5 of the third lens is concave, and there are differences in the relevant parameters and air space of the respective lenses of the lens.

Table 7 shows the parameters related to each lens of the optical imaging lens 400 according to the present embodiment.

TABLE 7

The surface shape coefficients of the aspherical surfaces of the optical imaging lens 400 in this embodiment are shown in table 8.

TABLE 8

The distortion diagram, the MTF diagram and the axial chromatic aberration diagram of the optical imaging lens 400 provided by the present embodiment are respectively shown in fig. 14, fig. 15 and fig. 16. As can be seen from fig. 14, the distortion of the optical imaging lens 400 in the present embodiment is entirely in the range of-10%, indicating that the optical imaging lens has small distortion; as can be seen from FIG. 15, the MTF value is greater than 0.55 under the condition of 83Lp/mm, which indicates that the imaging quality of the optical imaging lens is good, and as can be seen from FIG. 16, the axial chromatic aberration is between-0.01 mm and 0.03mm, which indicates that the optical imaging lens 400 has good achromatism performance.

Table 9 shows the four embodiments and their corresponding optical characteristics, which mainly include the effective focal length F, F #, the image height IH corresponding to the half field angle, the maximum field angle FOV and total optical length TTL of the optical imaging lens, and the values corresponding to each of the foregoing conditional expressions.

TABLE 9

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

(1) the effective focal lengths f of the optical imaging lens are larger than 10mm, which shows that the lens has a longer effective focal length, and the imaging performance of the lens in a long-distance view is improved.

(2) The first lens and the sixth lens are both glass aspheric lenses, and the surface type characteristic of the aspheric lenses is utilized to increase the light inlet quantity of the optical imaging lens, effectively reduce imaging distortion and improve imaging quality.

(3) The optical imaging lens uses an all-glass lens and a gluing process on a material. The full glass material lens can bring good thermal stability to the lens, so that the lens can still work normally in high and low temperature environments. The use of the cemented lens can improve the image quality and reduce the reflection loss of light energy, thereby improving the definition of imaging. The cemented lens consisting of the fourth lens and the fifth lens is introduced in the application, so that the chromatic aberration influence can be eliminated, and the tolerance sensitivity of the system is reduced; the fourth lens and the fifth lens which are simultaneously cemented can also leave partial chromatic aberration to balance the overall chromatic aberration of the optical system. In addition, the use of the cemented lens composed of the fourth lens and the fifth lens can also simplify the assembly procedure in the lens manufacturing process, facilitating the mass production of the lens.

In summary, the optical imaging lens provided by the invention adopts six full-glass lenses, and by reasonably distributing the focal power, the surface shape, the central thickness of each lens, the on-axis distance between each lens and the like, the lens has the advantages of long focal length, small distortion, small f-number, small volume, high thermal stability and good imaging quality while realizing good imaging quality.

Fifth embodiment

Referring to fig. 17, an imaging apparatus 500 according to a fifth embodiment of the present invention is shown, where the imaging apparatus 500 may include an imaging element 510 and an optical imaging lens (e.g., the optical imaging lens 100) in any of the embodiments described above. The imaging element 510 may be a CMOS (Complementary Metal Oxide Semiconductor) image sensor, and may also be a CCD (Charge Coupled Device) image sensor.

The imaging device 500 may be a vehicle-mounted monitoring device, a security device, an AR/VR device, a smart phone, or any other electronic device equipped with the optical imaging lens.

The imaging device 500 provided by the embodiment includes the optical imaging lens 100, and since the optical imaging lens 100 has the advantages of long focal length, small distortion, small f-number, small volume, high thermal stability and good imaging quality, the imaging device 500 having the optical imaging lens 100 also has the advantages of long focal length, small distortion, small f-number, small volume, high thermal stability and good imaging quality.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. An optical imaging lens, comprising, in order from an object side to an imaging surface along an optical axis: a first group having negative optical power, a second group having positive optical power, a third group having optical power;

the first group sequentially includes from an object side to an imaging surface along an optical axis:

the second lens is provided with negative focal power, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface;

the image side surface of the third lens is a convex surface;

the fourth lens and the fifth lens form a cemented lens;

a sixth lens having a optical power, an object-side surface of the sixth lens being convex at a paraxial region, an image-side surface of the sixth lens being concave at a paraxial region;

2. The optical imaging lens according to claim 1, wherein the optical imaging lens satisfies the following conditional expression:

-3<F1/f<-1；

-3<F1/F2<-1；

-0.5<F2/F3<1；

wherein F1 represents the effective focal length of the first group, F2 represents the effective focal length of the second group, F3 represents the effective focal length of the third group, and F represents the effective focal length of the optical imaging lens.

3. The optical imaging lens according to claim 1, wherein the optical imaging lens satisfies the conditional expression:

0.37<f/TTL<0.39；

0.015/°<D1/IH/FOV<0.025/°；

wherein, TTL represents the total optical length of the optical imaging lens, f represents the effective focal length of the optical imaging lens, D1 represents the effective aperture of the object-side surface of the first lens, FOV represents the maximum field angle of the optical imaging lens, and IH represents the image height corresponding to the half field angle of the optical imaging lens.

4. The optical imaging lens of claim 1, wherein the first lens is an aspheric lens, and the optical imaging lens satisfies the following conditional expression:

1.0<R1/R2<1.6；

1<f1/F1<5；

wherein R1 represents a radius of curvature of an object-side surface of the first lens, R2 represents a radius of curvature of an image-side surface of the first lens, F1 represents an effective focal length of the first lens, and F1 represents an effective focal length of the first group.

5. The optical imaging lens according to claim 1, wherein the optical imaging lens satisfies the conditional expression:

0.97<Vd4/Vd5<1；

wherein Vd4 denotes a material refractive index of the fourth lens, and Vd5 denotes a material refractive index of the fifth lens.

6. The optical imaging lens according to claim 1, wherein the optical imaging lens satisfies the conditional expression:

0<|CT56/f6|<0.1；

0.2mm/°<IH/CRA<0.4mm/°；

wherein CT56 denotes an air space on an optical axis between the fifth lens and the sixth lens, f6 denotes an effective focal length of the sixth lens, IH denotes an image height corresponding to a half field angle of the optical imaging lens, and CRA denotes a chief ray incident angle corresponding to a maximum field angle of the optical imaging lens.

7. The optical imaging lens according to claim 1, wherein the optical imaging lens satisfies the conditional expression:

5.0<TTL/D1<7.5；

F#<1.7；

wherein, TTL represents the optical total length of the optical imaging lens, D1 represents the effective aperture of the object side surface of the first lens, and F # represents the diaphragm number of the optical imaging lens.

8. The optical imaging lens according to claim 1, wherein the optical imaging lens satisfies the conditional expression:

2.0<f/IH<2.8；

wherein f represents the effective focal length of the optical imaging lens, and IH represents the image height corresponding to the half field angle of the optical imaging lens.

9. The optical imaging lens according to claim 1, wherein the optical imaging lens satisfies the conditional expression:

0.75<D1/D5<0.95；

wherein D1 represents the effective aperture of the object side surface of the first lens, and D5 represents the effective aperture of the object side surface of the third lens.

10. The optical imaging lens of claim 1, wherein the sixth lens has positive optical power, and an effective focal length f6 of the sixth lens and the effective focal length f of the optical imaging lens satisfy the conditional expression: 1< f6/f < 5.

11. The optical imaging lens of claim 1, wherein the sixth lens has a negative optical power, and an effective focal length f6 of the sixth lens and an effective focal length f of the optical imaging lens satisfy: -10< f6/f < -5.

12. An imaging apparatus comprising the optical imaging lens according to any one of claims 1 to 11 and an imaging element for converting an optical image formed by the optical imaging lens into an electric signal.