CN113900236B

CN113900236B - Wide-angle lens and imaging apparatus

Info

Publication number: CN113900236B
Application number: CN202111460989.0A
Authority: CN
Inventors: 章彬炜; 曾昊杰
Original assignee: Jiangxi Lianyi Optics Co Ltd
Current assignee: Jiangxi Lianyi Optics Co Ltd
Priority date: 2021-12-03
Filing date: 2021-12-03
Publication date: 2022-05-10
Anticipated expiration: 2041-12-03
Also published as: CN113900236A

Abstract

The invention discloses a wide-angle lens and imaging equipment, the wide-angle lens comprises the following components in sequence from an object side to an imaging surface along an optical axis: the first lens with negative focal power has a convex object-side surface and a concave image-side surface; a second lens having a focal power, wherein 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; a diaphragm; a third lens having a positive refractive power, both the object-side surface and the image-side surface of the third lens being convex; a fourth lens having a negative optical power, an image-side surface of which is concave at a paraxial region; a fifth lens element with positive optical power having a concave object-side surface at paraxial region and a convex image-side surface; a sixth lens having a negative optical power; a seventh lens having optical power. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all aspheric lenses. The wide-angle lens has the advantages of high pixel, super-large field angle and miniaturization.

Description

Wide-angle lens and imaging apparatus

Technical Field

The invention relates to the technical field of imaging lenses, in particular to a wide-angle lens and imaging equipment.

Background

In recent years, with the rise of smart phones, the demand of each large-brand flagship aircraft on high pixels is gradually increased, and the size of a light-sensitive surface matched with a general wide-angle lens is 1/4 inches, and the pixel size of the imaging chip is 800 ten thousand; compared with the leading lens matched with an imaging chip with 1/3 inches and 1300 ten thousand pixels, in order to increase the imaging pixels without reducing the pixel size of the photosensitive device, the chip size is made to be a development trend of high pixels, and therefore, the high-pixel and large wide-angle lens with good imaging quality is the mainstream in the market at present.

In order to obtain higher pixels and have good imaging quality, the traditional lens mounted on a mobile phone camera mostly adopts a five-piece or six-piece lens structure, and generally can only meet the requirements of 800 ten thousand or 1300 ten thousand pixels. However, with the development of technology and the increasing demand of diversified users, a seven-piece lens structure gradually appears in the lens design, and although a common seven-piece lens has good optical performance, the focal power, the lens pitch and the lens shape setting still have certain irrationality, so that the lens structure cannot meet the design requirements of high pixel and wide angle while having good optical performance.

Disclosure of Invention

Therefore, an object of the present invention is to provide a wide-angle lens and an imaging device, which have at least advantages of high pixel, large wide angle, miniaturization, and the like, and can meet the use requirements of miniaturized electronic devices.

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

In a first aspect, the present invention provides a wide-angle lens, comprising, 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 is provided with 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; a diaphragm; a third lens having a positive optical power, the third lens having convex object and image side surfaces; a fourth lens having a negative optical power, an image-side surface of the fourth lens being concave at a paraxial region; a fifth lens element having a positive optical power, an object-side surface of the fifth lens element being concave at a paraxial region and an image-side surface of the fifth lens element being convex; a sixth lens having a negative optical power, an object side surface of the sixth lens being convex at a paraxial region and having at least one inflection point, an image side surface of the sixth lens being concave at a paraxial region and having at least one inflection point; a seventh lens having optical power, an object side surface of the seventh lens being convex at a paraxial region and having at least one inflection point, an image side surface of the seventh lens being concave at a paraxial region and having at least one inflection point; wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are aspheric lenses; the wide-angle lens meets the following conditional expression: -18< f12/f < -1; 8.5mm < IH × tan θ <10.5 mm; where f12 denotes a combined focal length of the first lens and the second lens, f denotes an effective focal length of the wide-angle lens, θ denotes a half field angle of the wide-angle lens, and IH denotes an actual half image height of the wide-angle lens.

In a second aspect, the present invention provides an imaging apparatus including an imaging element for converting an optical image formed by the wide-angle lens into an electric signal, and the wide-angle lens provided in the first aspect.

Compared with the prior art, the wide-angle lens and the imaging equipment provided by the invention have the advantages that the wide-angle lens has high pixels and an ultra-wide angle by adopting seven aspheric lenses with specific focal power and matching specific surface shapes and reasonable focal power distribution, and can be matched with a 50M/108M (Megapixel ) imaging chip to realize ultra-high definition imaging; meanwhile, the combined focal power of the first lens and the second lens is reasonably distributed, and the off-axis aberration is reasonably corrected by using the aspheric surface, so that the lens has ultrahigh pixels and a larger field angle, and the use requirements of high pixels and wide angle of the portable electronic equipment are better met.

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 a wide-angle lens according to a first embodiment of the present invention;

fig. 2 is a graph showing f-tan θ distortion of a wide-angle lens according to a first embodiment of the present invention;

FIG. 3 is a field curvature diagram of a wide-angle lens according to a first embodiment of the present invention;

FIG. 4 is a vertical axis chromatic aberration diagram of the wide-angle lens according to the first embodiment of the present invention;

fig. 5 is a schematic structural diagram of a wide-angle lens according to a second embodiment of the present invention;

fig. 6 is a graph showing f-tan θ distortion of a wide-angle lens according to a second embodiment of the present invention;

FIG. 7 is a field curvature diagram of a wide-angle lens according to a second embodiment of the present invention;

FIG. 8 is a vertical axis chromatic aberration diagram of a wide-angle lens according to a second embodiment of the present invention;

fig. 9 is a schematic structural diagram of a wide-angle lens according to a third embodiment of the present invention;

fig. 10 is a graph showing f-tan θ distortion of a wide-angle lens according to a third embodiment of the present invention;

fig. 11 is a field curvature diagram of a wide-angle lens according to a third embodiment of the present invention;

fig. 12 is a vertical axis chromatic aberration diagram of a wide-angle lens according to a third embodiment of the present invention;

fig. 13 is a schematic structural diagram of a wide-angle lens according to a fourth embodiment of the present invention;

fig. 14 is a graph showing f-tan θ distortion of a wide-angle lens according to a fourth embodiment of the present invention;

fig. 15 is a field curvature graph of a wide-angle lens according to a fourth embodiment of the present invention;

fig. 16 is a vertical axis chromatic aberration diagram of a wide-angle lens according to a fourth embodiment of the present invention;

FIG. 17 is a schematic diagram illustrating a vertical distance between an inflection point on an object-side surface of the sixth lens element and an image-side surface of the seventh lens element and an optical axis;

fig. 18 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 more comprehensible, embodiments accompanying 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 a wide-angle lens, which sequentially comprises the following components from an object side to an imaging surface along an optical axis: the lens comprises a first lens, a second lens, a diaphragm, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an optical filter.

A first lens in the wide-angle lens has negative focal power, 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 has 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;

a diaphragm;

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

the fourth lens has a negative optical power, and the image side surface of the fourth lens is concave at the paraxial region;

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

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

the seventh lens has optical power, an object side surface of the seventh lens is convex at a paraxial region and has at least one inflection point, and an image side surface of the seventh lens is concave at the paraxial region and has at least one inflection point;

the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all aspheric lenses; the wide-angle lens adopts a seven-piece aspheric lens combination, has a large field angle and ultrahigh pixels through specific surface shape collocation and reasonable focal power distribution, and can be matched with a 50M/108M imaging chip to realize ultrahigh-definition imaging.

Further, the wide-angle lens satisfies the following conditional expression:

-18<f12/f<-1；（1）

8.5mm<IH×tanθ<10.5mm；（2）

where f12 denotes a combined focal length of the first lens and the second lens, f denotes an effective focal length of the wide-angle lens, θ denotes a half field angle of the wide-angle lens, and IH denotes an actual half image height of the wide-angle lens. Satisfying the above conditional expression (1), the focal power of the first group consisting of the first lens and the second lens can be reasonably distributed, the focal power of the second group consisting of the third lens to the seventh lens can be properly balanced, the purpose of correcting the on-axis spherical aberration and the axial chromatic aberration of the optical system is achieved, and the improvement of the imaging quality of the system is facilitated; the condition (2) is satisfied, so that the system can realize wide angle and has high pixels; the condition formulas (1) and (2) are simultaneously satisfied, which shows that the system has the characteristics of high imaging quality, wide field angle and high pixel.

In some embodiments, the wide-angle lens satisfies the following conditional expression:

-25<f1/f<-2；（3）

0<(R11-R12)/(R11+R12)<0.4；（4）

where f1 denotes an effective focal length of the first lens, f denotes an effective focal length of the wide-angle lens, R11 denotes a radius of curvature of an object-side surface of the first lens, and R12 denotes a radius of curvature of an image-side surface of the first lens. Satisfying above-mentioned conditional expressions (3) and (4), through the shape of face and the focus of reasonable restriction first lens, be favorable to revising off-axis aberration to let the light that gets into first lens can have appropriate incident and exit angle, help increasing the area of image plane, reduce the external diameter of camera lens front end lens, maintain the system miniaturization.

0.03<CT2/TTL<0.1；（5）

wherein CT2 denotes the center thickness of the second lens on the optical axis, and TTL denotes the total optical length of the wide-angle lens. Satisfying above-mentioned conditional expression (5), through the central thickness of reasonable restriction second lens, can effectively avoid the second lens to cross the problem of thin easy cracked limit in the assembling process, can maintain the frivolousization of entire system simultaneously.

AC23/TTL<0.03；（6）

where AC23 denotes an air gap on the optical axis between the second lens and the third lens, and TTL denotes the total optical length of the wide-angle lens. Satisfying the above conditional expression (6), through the air gap between the second lens and the third lens of rational restriction, can make the light deflection tend to slow, be favorable to reducing the sensitivity of system.

-20<f1/f3<-2；（7）

1.4<SD11/SD32<2.0；（8）

where f1 denotes an effective focal length of the first lens, f3 denotes an effective focal length of the third lens, SD11 denotes an effective aperture of the object-side surface of the first lens, and SD32 denotes an effective aperture of the image-side surface of the third lens. Satisfying above-mentioned conditional expressions (7) and (8), through the focus ratio of reasonable setting first, three lens to make the third lens have less bore, can make the light that jets out from first lens deflect and tend to slowly, be favorable to reducing the sensitivity of system, improve holistic imaging quality.

0.18<CT5/TTL<0.25；（9）

0.5<f5/f<1；（10）

where f5 denotes an effective focal length of the fifth lens, f denotes an effective focal length of the wide-angle lens, CT5 denotes a center thickness of the fifth lens on the optical axis, and TTL denotes an optical total length of the wide-angle lens. Satisfy above-mentioned conditional expression (9) and (10), through the thickness and the focus ratio of reasonable setting fifth lens, be favorable to the correction of follow-up system aberration, improve the formation of image quality.

0.22<EPD/IH<0.35；（11）

0.9<EPD/BFL<1.2；（12）

and the EPD represents the entrance pupil diameter of the wide-angle lens, the IH represents the actual half-image height of the wide-angle lens, and the BFL represents the back focal length of the wide-angle lens. Satisfying the above conditional expression (11), enough light can enter the lens, the reasonable balance between the large light flux and the large imaging surface of the lens can be better realized, and the imaging quality can be improved. The conditional expression (12) is satisfied, and a shorter back focus is obtained under the configuration of a large light-passing aperture, so that the image module is further miniaturized, and the requirements of light weight and thinness of electronic equipment are better met.

0.4<(R61-R62)/(R61+R62)<0.5；（13）

0<(R71-R72)/(R71+R72)<0.35；（14）

where R61 denotes a radius of curvature of an object-side surface of the sixth lens, R62 denotes a radius of curvature of an image-side surface of the sixth lens, R71 denotes a radius of curvature of an object-side surface of the seventh lens, and R72 denotes a radius of curvature of an image-side surface of the seventh lens. The sixth lens and the seventh lens both have an inflection point, the above conditional expressions (13) and (14) are satisfied, and by adjusting the surface shapes of the sixth lens and the seventh lens at a paraxial region, the shape change of the sixth lens and the seventh lens can be reduced, the generation of stray light can be reduced, and the manufacturability of the lenses can be improved.

0.15<Y_R61/IH<0.35；（15）

0.3<Y_R72/IH<0.45；（16）

wherein, Y_R61Denotes the perpendicular distance, Y, of the inflection point on the object-side surface of the sixth lens element from the optical axis_R72Denotes a vertical distance of an inflection point on an image-side surface of the seventh lens element from the optical axis, specifically Y_R61、Y_R72Can be seen in fig. 17, IH represents the actual half-image height of the wide-angle lens. The object side surface of the sixth lens and the image side surface of the seventh lens are provided with inflection points, so that the conditional expressions (15) and (16) are satisfied, the positions of the inflection points on the object side surface of the sixth lens and the image side surface of the seventh lens can be reasonably limited, coma aberration correction of an off-axis field of view can be enhanced, meanwhile, good convergence field curvature is realized, and the imaging quality is improved.

In some embodiments, the object-side surface of the fourth lens in the wide-angle lens is convex, and in other embodiments, the object-side surface of the fourth lens is concave. The fourth lens adopts different surface types for matching and combining, and can enable the system to achieve a good imaging effect.

As an implementation mode, a full plastic lens can be adopted, and glass and plastic can be mixed and matched, so that a good imaging effect can be achieved; in this application, for the volume that reduces the camera lens better and reduce cost, adopt seven plastic lens combinations, through specific surface shape collocation and reasonable focal power distribution for wide-angle camera lens has big wide angle and the characteristics of superelevation pixel, can match 50M 108M's imaging chip and realize super wide angle high definition formation of image. The first lens to the seventh lens are plastic aspheric lenses, and aspheric lenses are adopted, so that cost can be effectively reduced, aberration can be corrected, and a product with higher performance-price ratio can be provided.

The invention is further illustrated below in the following examples. In various embodiments, the thickness, the curvature radius, and the material selection of each lens in the wide-angle lens are different, and the specific differences can be referred to in the parameter tables of the various embodiments. 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 lens in the wide-angle lens is an aspherical lens, the aspherical surface type of the lens satisfies the following equation:

；

wherein z is the distance rise from the aspheric surface vertex when the aspheric surface is at the position with the height h along the optical axis direction, c is the paraxial curvature of the surface, k is the quadric coefficient, A_2iIs the aspheric surface type coefficient of 2i order.

First embodiment

Referring to fig. 1, a schematic structural diagram of a wide-angle lens 100 according to a first embodiment of the present invention is shown, where the wide-angle lens 100 sequentially includes, from an object side to an image plane along an optical axis: a first lens L1, a second lens L2, an aperture stop ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and a filter G1.

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 positive focal power, the object side surface S3 of the second lens is a concave surface, and the image side surface S4 of the second lens is a convex surface;

the third lens L3 has positive focal power, the object-side surface S5 of the third lens is convex, and the image-side surface S6 of the third lens is convex;

the fourth lens element L4 has a negative power, with an object-side surface S7 of the fourth lens element being convex at the paraxial region and an image-side surface S8 of the fourth lens element being concave at the paraxial region;

the fifth lens element L5 has positive optical power, an object-side surface S9 of the fifth lens element being concave at the paraxial region and an image-side surface S10 of the fifth lens element being convex;

the sixth lens element L6 has negative optical power, the object-side surface S11 of the sixth lens element is convex at the paraxial region, the image-side surface S12 of the sixth lens element is concave at the paraxial region, and the object-side surface S11 and the image-side surface S12 of the sixth lens element have an inflection point;

the seventh lens element L7 has negative power, the object-side surface S13 of the seventh lens element is convex at the paraxial region, the image-side surface S14 of the seventh lens element is concave at the paraxial region, and the object-side surface S13 and the image-side surface S14 of the seventh lens element have an inflection point.

The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are all plastic aspheric lenses.

Specifically, the design parameters of each lens of the wide-angle lens 100 provided in the present embodiment are shown in table 1.

TABLE 1

In the present embodiment, aspheric parameters of the respective lenses in the wide-angle lens 100 are shown in table 2.

TABLE 2

Referring to fig. 2, fig. 3 and fig. 4, a f-tan θ distortion curve, a field curvature curve and a vertical axis chromatic aberration curve of the wide-angle lens 100 are shown, respectively. It can be seen from fig. 2 that the optical distortion is controlled within ± 20%, indicating that the distortion of the wide-angle lens 100 is well corrected; it can be seen from fig. 3 that the curvature of field is controlled within ± 0.07mm, which indicates that the wide-angle lens 100 has better curvature of field correction; it can be seen from fig. 4 that the vertical axis chromatic aberration at different wavelengths is controlled within ± 2 microns, which indicates that the vertical axis chromatic aberration of the wide-angle lens 100 is well corrected; as can be seen from fig. 2, 3, and 4, the aberration of the wide-angle lens 100 is well balanced, and has good optical imaging quality.

Second embodiment

As shown in fig. 5, which is a schematic structural diagram of the wide-angle lens 200 of the present embodiment, the wide-angle lens 200 of the present embodiment is substantially the same as the first embodiment, and mainly differs in the curvature radius, aspheric coefficient, thickness, and material of each lens surface.

Specifically, the design parameters of the wide-angle lens 200 provided in this embodiment are shown in table 3.

TABLE 3

In the present embodiment, aspheric parameters of the respective lenses in wide-angle lens 200 are shown in table 4.

TABLE 4

Referring to fig. 6, 7 and 8, which are a f-tan θ distortion graph, a field curvature graph and a vertical axis chromatic aberration graph of the wide-angle lens 200, respectively, it can be seen from fig. 6 that the optical distortion is controlled within ± 20%, which indicates that the distortion of the wide-angle lens 200 is well corrected; it can be seen from fig. 7 that the curvature of field is controlled within ± 0.1mm, which indicates that the wide-angle lens 200 has better curvature of field correction; it can be seen from fig. 8 that the vertical chromatic aberration at different wavelengths is controlled within ± 2.5 microns, which indicates that the vertical chromatic aberration of the wide-angle lens 200 is well corrected; as can be seen from fig. 6, 7, and 8, the aberrations of wide-angle lens 200 are well balanced, and the optical imaging quality is good.

Third embodiment

As shown in fig. 9, which is a schematic structural diagram of the wide-angle lens 300 provided in this embodiment, the wide-angle lens 300 of this embodiment is substantially the same as the first embodiment, except that: the second lens element L2 of the wide-angle lens 300 in this embodiment has negative power, the object-side surface S7 of the fourth lens element is concave at the paraxial region, and the curvature radius, aspheric coefficient, thickness, and material of each lens element are different.

Specifically, the design parameters of the wide-angle lens 300 provided in this embodiment are shown in table 5.

TABLE 5

In the present embodiment, aspheric parameters of the respective lenses in the wide-angle lens 300 are shown in table 6.

TABLE 6

Referring to fig. 10, fig. 11 and fig. 12, which are a f-tan θ distortion graph, a field curvature graph and a vertical axis chromatic aberration graph of the wide-angle lens 300, respectively, it can be seen from fig. 10 that the optical distortion is controlled within ± 20%, which indicates that the distortion of the wide-angle lens 300 is well corrected; it can be seen from fig. 11 that the paraxial curvature of field is controlled within ± 0.18mm, which indicates that the curvature of field of the wide-angle lens 300 is better corrected; it can be seen from fig. 12 that the vertical chromatic aberration at different wavelengths is controlled within ± 1.3 microns, which indicates that the vertical chromatic aberration of the wide-angle lens 300 is well corrected; as can be seen from fig. 10, 11, and 12, the aberration of wide-angle lens 300 is well balanced, and has good optical imaging quality.

Fourth embodiment

As shown in fig. 13, which is a schematic structural diagram of the wide-angle lens 400 provided in this embodiment, the wide-angle lens 400 of this embodiment is substantially the same as the first embodiment, except that: the wide-angle lens 400 of the present embodiment has negative power for the second lens L2, positive power for the seventh lens L7, concave object-side surface S7 of the fourth lens at the paraxial region, and different radii of curvature, aspheric coefficients, thicknesses, and materials for the lens surfaces.

Specifically, the design parameters of the wide-angle lens 400 provided in this embodiment are shown in table 7.

TABLE 7

In the present embodiment, aspheric parameters of the respective lenses in the wide-angle lens 400 are shown in table 8.

TABLE 8

Referring to fig. 14, 15 and 16, which are a f-tan θ distortion graph, a field curvature graph and a vertical axis chromatic aberration graph of the wide-angle lens 400, respectively, it can be seen from fig. 14 that the optical distortion is controlled within ± 23%, which indicates that the distortion of the wide-angle lens 400 is well corrected; it can be seen from fig. 15 that the paraxial curvature of field is controlled within ± 0.1mm, which indicates that the curvature of field of the wide-angle lens 300 is better corrected; it can be seen from fig. 16 that the vertical axis chromatic aberration at different wavelengths is controlled within ± 3 microns, which indicates that the vertical axis chromatic aberration of the wide-angle lens 400 is well corrected; it can be seen from fig. 14, 15 and 16 that the aberrations of the wide-angle lens 400 are well balanced, and the optical imaging quality is good.

Please refer to table 9, which shows the optical characteristics corresponding to the wide-angle lens provided in the above four embodiments, including the field angle 2 θ, the total optical length TTL, the actual half-image height IH, the effective focal length f, and the related values corresponding to each of the aforementioned conditional expressions.

TABLE 9

It can be seen from the f-tan θ distortion curve graph, the field curvature curve graph and the vertical axis chromatic aberration curve graph of each embodiment that the f-tan θ distortion value, the field curvature value and the vertical axis chromatic aberration value of the wide-angle lens in each embodiment are within ± 23%, within ± 0.18mm and within ± 3 microns, which indicates that the lens provided by the embodiment of the invention has the advantages of high pixel, super wide angle, low sensitivity and the like, and has good resolving power.

In summary, the wide-angle lens provided by the invention adopts seven aspheric lenses with specific focal power, and through specific surface shape collocation and reasonable focal power distribution, the wide-angle lens has the advantages of high pixel and super wide angle, and can be matched with a 50M/108M (Megapixel ) imaging chip to realize ultra-high definition imaging; meanwhile, the combined focal power of the first lens and the second lens is reasonably distributed, and the off-axis aberration is reasonably corrected by using the aspheric surface, so that the lens has ultrahigh pixels and a larger field angle, and the use requirements of high pixels and wide angle of the portable electronic equipment are better met.

Fifth embodiment

Referring to fig. 18, an imaging device 500 according to a fifth embodiment of the present invention is shown, where the imaging device 500 may include an imaging element 510 and a wide-angle lens (e.g., wide-angle 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 smart phone, a vehicle-mounted monitoring device, a security device, an AR/VR device, or any other electronic device equipped with the wide-angle lens.

The embodiment provides an imaging apparatus 500 including the wide-angle lens 100, and since the wide-angle lens 100 has advantages of high pixel, super-large field angle, and miniaturization, the imaging apparatus 500 having the wide-angle lens 100 also has advantages of high pixel, super-large field angle, and miniaturization.

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. A wide-angle lens, comprising seven lenses 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 is provided with 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;

a diaphragm;

a third lens having a positive optical power, the third lens having convex object and image side surfaces;

a fourth lens having a negative optical power, an image-side surface of the fourth lens being concave at a paraxial region;

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

a sixth lens having a negative optical power, an object side surface of the sixth lens being convex at a paraxial region and having at least one inflection point, an image side surface of the sixth lens being concave at a paraxial region and having at least one inflection point;

a seventh lens having optical power, an object side surface of the seventh lens being convex at a paraxial region and having at least one inflection point, an image side surface of the seventh lens being concave at a paraxial region and having at least one inflection point;

wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are aspheric lenses;

the wide-angle lens meets the following conditional expression:

-18<f12/f<-1；

8.5mm<IH×tanθ<10.5mm；

0.03<CT2/TTL<0.1；

wherein f12 denotes a combined focal length of the first lens and the second lens, f denotes an effective focal length of the wide-angle lens, θ denotes a half field angle of the wide-angle lens, IH denotes an actual half image height of the wide-angle lens, CT2 denotes a center thickness of the second lens on an optical axis, and TTL denotes an optical total length of the wide-angle lens.

2. The wide-angle lens of claim 1, wherein the wide-angle lens satisfies the following conditional expression:

-25<f1/f<-2；

0<(R11-R12)/(R11+R12)<0.4；

where f1 represents the effective focal length of the first lens, R11 represents the radius of curvature of the object-side surface of the first lens, and R12 represents the radius of curvature of the image-side surface of the first lens.

3. The wide-angle lens of claim 1, wherein the wide-angle lens satisfies the following conditional expression:

AC23/TTL<0.03；

wherein AC23 denotes an air gap on an optical axis between the second lens and the third lens, and TTL denotes an optical total length of the wide-angle lens.

4. The wide-angle lens of claim 1, wherein the wide-angle lens satisfies the following conditional expression:

-20<f1/f3<-2；

1.4<SD11/SD32<2.0；

wherein f1 denotes an effective focal length of the first lens, f3 denotes an effective focal length of the third lens, SD11 denotes an effective aperture of an object side surface of the first lens, and SD32 denotes an effective aperture of an image side surface of the third lens.

5. The wide-angle lens of claim 1, wherein the wide-angle lens satisfies the following conditional expression:

0.18<CT5/TTL<0.25；

0.5<f5/f<1；

where f5 denotes an effective focal length of the fifth lens, CT5 denotes a center thickness of the fifth lens on an optical axis, and TTL denotes an optical total length of the wide-angle lens.

6. The wide-angle lens of claim 1, wherein the wide-angle lens satisfies the following conditional expression:

0.22<EPD/IH<0.35；

0.9<EPD/BFL<1.2；

and the EPD represents the entrance pupil diameter of the wide-angle lens, and the BFL represents the back focal length of the wide-angle lens.

7. The wide-angle lens of claim 1, wherein the wide-angle lens satisfies the following conditional expression:

0.4<(R61-R62)/(R61+R62)<0.5；

0<(R71-R72)/(R71+R72)<0.35；

wherein R61 denotes a radius of curvature of an object-side surface of the sixth lens, R62 denotes a radius of curvature of an image-side surface of the sixth lens, R71 denotes a radius of curvature of an object-side surface of the seventh lens, and R72 denotes a radius of curvature of an image-side surface of the seventh lens.

8. The wide-angle lens of claim 1, wherein the wide-angle lens satisfies the following conditional expression:

0.15<Y_R61/IH<0.35；

0.3<Y_R72/IH<0.45；

wherein, Y_R61Denotes a vertical distance, Y, of an inflection point on an object-side surface of the sixth lens element from an optical axis_R72And the vertical distance between an inflection point on the image side surface of the seventh lens and an optical axis is represented.

9. An imaging apparatus comprising the wide-angle lens according to any one of claims 1 to 8, and an imaging element for converting an optical image formed by the wide-angle lens into an electrical signal.