CN107144943B

CN107144943B - Camera lens

Info

Publication number: CN107144943B
Application number: CN201710585219.6A
Authority: CN
Inventors: 黄林
Original assignee: Zhejiang Sunny Optics Co Ltd
Current assignee: Zhejiang Sunny Optics Co Ltd
Priority date: 2017-07-18
Filing date: 2017-07-18
Publication date: 2022-09-09
Anticipated expiration: 2037-07-18
Also published as: CN107144943A

Abstract

The application discloses camera lens, this camera lens includes by order along optical axis from the thing side to picture side: a first lens, a second lens, a third lens and a fourth lens with optical power. Wherein at least one of the first lens and the second lens has a positive optical power; the object side surface of the third lens and the image side surface of the fourth lens are both concave surfaces; and the half of the diagonal length of the effective pixel area on the imaging surface of the camera lens, ImgH, and the total effective focal length f of the camera lens meet the condition that ImgH/f is more than 1.

Description

Camera lens

Technical Field

The present invention relates to an image pickup lens, and more particularly, to a wide-angle image pickup lens including four lenses.

Background

With the development of chip technologies such as CCD and CMOS, imaging lenses are also gradually being developed in the fields of miniaturization, weight reduction, and high pixel. In some application fields, a corresponding requirement is also placed on a large field range of the lens, and the lens is required to have a wide-angle characteristic while satisfying miniaturization and high imaging quality. In addition, in order to realize stable mass production, the lens is also required to have good sensitivity.

In order to achieve the wide angle characteristic, the field angle of the lens is usually enlarged by increasing the number of lenses, but this method is not favorable for realizing the miniaturization and light weight of the lens; meanwhile, the reduction of various aberrations is limited by the excessive number of lens pieces, which is not beneficial to improving the imaging quality of the lens.

Therefore, there is a need to provide a wide-angle imaging lens having a compact structure, high image quality, and low sensitivity without increasing the number of lens elements.

Disclosure of Invention

The present application provides an image pickup lens, such as a wide-angle lens, applicable to a portable electronic product, which can solve at least or partially at least one of the above-mentioned disadvantages of the related art.

One aspect of the present application provides an imaging lens, in order from an object side to an image side along an optical axis, comprising: a first lens, a second lens, a third lens and a fourth lens with optical power. Wherein at least one of the first lens and the second lens may have a positive optical power; the object side surface of the third lens and the image side surface of the fourth lens can both be concave surfaces; and the half of the diagonal length of the effective pixel area on the imaging surface of the camera lens, namely ImgH, and the total effective focal length f of the camera lens can meet the condition that ImgH/f is more than 1.

In one embodiment, the first lens and the second lens may each have a positive optical power; the effective focal length f1 of the first lens and the effective focal length f2 of the second lens can satisfy the condition that f1/f2 is more than or equal to 7.

In one embodiment, the radius of curvature R5 of the object-side surface of the third lens and the radius of curvature R6 of the image-side surface of the third lens can satisfy 0.7 < R5/R6 < 1.2.

In one embodiment, the imaging lens may further include a stop disposed between the first lens and the second lens.

In one embodiment, the object-side surface of the first lens element can be convex, and the image-side surface of the second lens element can be convex.

In one embodiment, the central thickness CT2 of the second lens element on the optical axis and the distance TTL between the center of the object-side surface of the first lens element and the imaging plane of the camera lens on the optical axis satisfy 0.1 < CT2/TTL < 0.22.

In one embodiment, the distance T12 between the first lens and the second lens on the optical axis and the distance TTL between the center of the object side surface of the first lens and the imaging surface of the imaging lens on the optical axis satisfy 0.8 < (T12 x 10)/TTL < 1.5.

In one embodiment, the edge thickness ET4 of the fourth lens and the central thickness CT4 of the fourth lens on the optical axis satisfy 1 < ET4/CT4 < 1.5.

In one embodiment, the effective radius DT12 of the image side surface of the first lens and the effective radius DT22 of the image side surface of the second lens can satisfy 0.7 < DT12/DT22 < 1.3.

In one embodiment, the effective radius DT11 of the object side surface of the first lens and the effective radius DT32 of the image side surface of the third lens can satisfy 0.9 < DT11/DT32 < 1.3.

In one embodiment, the distance SAG42 between the intersection point of the image side surface of the fourth lens and the optical axis and the effective radius vertex of the image side surface of the fourth lens on the optical axis and the central thickness CT4 of the fourth lens on the optical axis satisfy 0.2 < SAG42/CT4 < 0.6.

In one embodiment, the imaging lens may further include a band pass filter disposed between the fourth lens and an imaging surface of the imaging lens, and a band pass wavelength of the band pass filter may be in a range of 400nm to 800 nm.

Another aspect of the present application provides an imaging lens, comprising, in order from an object side to an image side along an optical axis: the lens comprises a first lens, a second lens, a third lens and a fourth lens. Wherein the first lens and the second lens can both have positive focal power; the third lens can have positive focal power or negative focal power, and the object side surface of the third lens can be a concave surface; the fourth lens can have positive focal power or negative focal power, and the image side surface of the fourth lens can be a concave surface; and the edge thickness ET4 of the fourth lens and the central thickness CT4 of the fourth lens on the optical axis can satisfy 1 < ET4/CT4 < 1.5.

In one embodiment, the object-side surface of the first lens element can be convex, and the image-side surface of the second lens element can be convex; the imaging lens may further include a diaphragm disposed between the first lens and the second lens.

In one embodiment, the effective focal length f1 of the first lens and the effective focal length f2 of the second lens can satisfy 3 < f1/f2 ≦ 7.

In one embodiment, the imaging lens may further include a bandpass filter disposed between the fourth lens and an imaging surface of the imaging lens.

In one embodiment, the bandpass wavelength range of the bandpass filter may be 400nm to 800 nm.

In one embodiment, ImgH of half the diagonal length of the effective pixel area on the imaging surface of the imaging lens and the total effective focal length f of the imaging lens may satisfy ImgH/f > 1.

Another aspect of the present application further provides an imaging lens, in order from an object side to an image side along an optical axis, comprising: the lens comprises a first lens, a second lens, a third lens and a fourth lens. Wherein the first lens and the second lens can both have positive focal power; the third lens can have positive focal power or negative focal power, and the object side surface of the third lens can be a concave surface; the fourth lens can have positive focal power or negative focal power, and the image side surface of the fourth lens can be a concave surface; and the effective radius DT12 of the image side surface of the first lens and the effective radius DT22 of the image side surface of the second lens can satisfy 0.7 < DT12/DT22 < 1.3.

Another aspect of the present application further provides an imaging lens, in order from an object side to an image side along an optical axis, comprising: the lens comprises a first lens, a second lens, a third lens and a fourth lens. Wherein the first lens and the second lens can both have positive focal power; the third lens can have positive focal power or negative focal power, and the object side surface of the third lens can be a concave surface; the fourth lens can have positive focal power or negative focal power, and the image side surface of the fourth lens can be a concave surface; and the effective radius DT11 of the object side surface of the first lens and the effective radius DT32 of the image side surface of the third lens can satisfy 0.9 < DT11/DT32 < 1.3.

Another aspect of the present application further provides an imaging lens, in order from an object side to an image side along an optical axis, comprising: the lens comprises a first lens, a second lens, a third lens and a fourth lens. Wherein the first lens and the second lens can both have positive focal power; the third lens can have positive focal power or negative focal power, and the object side surface of the third lens can be a concave surface; the fourth lens can have positive focal power or negative focal power, and the image side surface of the fourth lens can be a concave surface; and the distance SAG42 between the intersection point of the image side surface of the fourth lens and the optical axis and the effective radius vertex of the image side surface of the fourth lens on the optical axis and the central thickness CT4 of the fourth lens on the optical axis can satisfy 0.2 < SAG42/CT4 < 0.6.

Another aspect of the present application further provides an imaging lens, in order from an object side to an image side along an optical axis, comprising: the lens comprises a first lens, a second lens, a third lens and a fourth lens. Wherein the first lens and the second lens can both have positive focal power; the third lens can have positive focal power or negative focal power, and the object side surface of the third lens can be a concave surface; the fourth lens can have positive power or negative power, and the image side surface of the fourth lens can be concave. The camera lens can further comprise a band-pass filter arranged between the fourth lens and the imaging surface of the camera lens, and the band-pass wavelength range of the band-pass filter can be 400nm to 800 nm.

The present application employs a plurality of (e.g., four) lenses, and by reasonably distributing the focal power, the surface shape, the center thickness of each lens, and the on-axis distance between lenses, the imaging lens can have at least one of the following advantages:

the field angle is enlarged, and the wide angle of the lens is realized;

the structure is compact, and the miniaturization of the lens is realized;

the sensitivity of the lens is reduced; and

and various aberrations are corrected, and the imaging quality of the lens is improved.

Drawings

Other features, objects, and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments when taken in conjunction with the accompanying drawings. In the drawings:

fig. 1 shows a schematic configuration diagram of an imaging lens according to embodiment 1 of the present application;

fig. 2A to 2C show an axial chromatic aberration curve, an astigmatism curve, and a distortion curve of the imaging lens of embodiment 1, respectively;

fig. 3 shows a schematic configuration diagram of an imaging lens according to embodiment 2 of the present application;

fig. 4A to 4C show an axial chromatic aberration curve, an astigmatism curve, and a distortion curve of the imaging lens of embodiment 2, respectively;

fig. 5 shows a schematic configuration diagram of an imaging lens according to embodiment 3 of the present application;

fig. 6A to 6C show an axial chromatic aberration curve, an astigmatism curve, and a distortion curve of the imaging lens of embodiment 3, respectively;

fig. 7 is a schematic configuration diagram showing an imaging lens according to embodiment 4 of the present application;

fig. 8A to 8C show an axial chromatic aberration curve, an astigmatism curve, and a distortion curve of the imaging lens of embodiment 4, respectively.

Detailed Description

For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of exemplary embodiments of the present application and does not limit the scope of the present application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that in this specification, the expressions first, second, third, etc. are used only to distinguish one feature from another, and do not represent any limitation on the features. Thus, the first lens discussed below may also be referred to as the second lens or the third lens without departing from the teachings of the present application.

In the drawings, the thickness, size, and shape of the lens have been slightly exaggerated for convenience of explanation. In particular, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shape of the spherical surface or the aspherical surface is not limited to the shape of the spherical surface or the aspherical surface shown in the drawings. The figures are purely diagrammatic and not drawn to scale.

Herein, the paraxial region refers to a region 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 surface of each lens closest to the object is called the object side surface, and the surface of each lens closest to the image plane is called the image side surface.

It will be further understood that the terms "comprises," "comprising," "has," "having," "includes" and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Moreover, when a statement such as "at least one of" appears after a list of listed features, the entirety of the listed features is modified rather than modifying individual elements in the list. Furthermore, when describing embodiments of the present application, the use of "may" mean "one or more embodiments of the present application. Also, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.

The features, principles, and other aspects of the present application are described in detail below.

An image pickup lens according to an exemplary embodiment of the present application includes, for example, four lenses having optical power, i.e., a first lens, a second lens, a third lens, and a fourth lens. The four lenses are arranged in order from the object side to the image side along the optical axis. The camera lens can further comprise a photosensitive element arranged on an imaging surface.

In an exemplary embodiment, the first lens may have a positive optical power; the second lens may have a positive optical power; the third lens has positive focal power or negative focal power, and the object side surface of the third lens can be a concave surface; and the fourth lens has positive power or negative power, and the image side surface of the fourth lens can be a concave surface.

The camera lens can further comprise a diaphragm arranged between the first lens and the second lens so as to further improve the imaging quality of the camera lens. Optionally, the object-side surface of the first lens element can be convex, and the image-side surface of the first lens element can be concave; the object-side surface of the second lens element can be concave, and the image-side surface can be convex. Through the arrangement, the first lens and the second lens form an approximately symmetrical structure by taking the diaphragm as the center, so that the lens sensitivity can be effectively reduced.

Between the effective focal length f1 of the first lens and the effective focal length f2 of the second lens, 3 < f1/f2 ≦ 7 may be satisfied, and more specifically, f1 and f2 may further satisfy 5.66 ≦ f1/f2 ≦ 7.00. The ratio of f1 to f2 is controlled in a reasonable range, so that the over concentration of focal power can be effectively avoided, the sensitivity of the lens is reduced, and the imaging quality of the lens can be improved.

The curvature radius R5 of the object side surface of the third lens and the curvature radius R6 of the image side surface of the third lens can satisfy 0.7 < R5/R6 < 1.2, and more specifically, R5 and R6 can further satisfy 0.72 < R5/R6 < 1.14, so that the lens sensitivity is reduced and the lens quality is improved.

The total optical length TTL (i.e., the distance on the optical axis between the center of the object side surface of the first lens element and the imaging surface of the imaging lens) between the second lens element and the center thickness CT2 on the optical axis and the imaging lens can satisfy 0.1 < CT2/TTL < 0.22, and more specifically, CT2 and TTL can further satisfy 0.14 < CT2/TTL < 0.21. The reasonable arrangement of the CT2 and the TTL is beneficial to shortening the total optical length of the lens and realizing miniaturization and wide angle.

The distance T12 between the first lens and the second lens on the optical axis and the total optical length TTL of the pick-up lens can satisfy 0.8 < (T12 x 10)/TTL < 1.5, more specifically, T12 and TTL can further satisfy 0.81 ≦ T12 x 10)/TTL ≦ 1.49. The reasonable arrangement of the T12 and the TTL can lead the lens to have a more compact structure, and simultaneously can reduce the sensitivity of the lens and improve the imaging quality.

The edge thickness ET4 of the fourth lens and the central thickness CT4 of the fourth lens on the optical axis can satisfy 1 & lt ET4/CT4 & lt 1.5, more specifically, ET4 and CT4 further satisfy 1.08 & lt ET4/CT4 & lt 1.36, so that the correction of the angle of the principal ray is realized, and the relative illumination of the lens is improved.

Optionally, the image-side surface of the fourth lens may have at least one point of inflection (i.e., the image-side surface of the fourth lens has at least a tendency to change from concave to convex from center to edge) such that the image-side surface of the fourth lens is concave at the paraxial region and convex at the peripheral region away from the optical axis, thereby effectively reducing sensitivity; meanwhile, the plane type arrangement can effectively suppress the angle of the light rays of the off-axis field of view entering the photosensitive element, increase the receiving efficiency of the photosensitive element and further correct the aberration of the off-axis field of view.

The effective radius DT12 of the image side surface of the first lens and the effective radius DT22 of the image side surface of the second lens can satisfy 0.7 < DT12/DT22 < 1.3, and more specifically, DT12 and DT22 further satisfy 0.78 < DT12/DT22 < 1.27, so that the wide-angle effect is realized.

The effective radius DT11 of the object side surface of the first lens and the effective radius DT32 of the image side surface of the third lens can satisfy 0.9 < DT11/DT32 < 1.3, and more specifically, DT11 and DT32 further can satisfy 1.00 < DT11/DT32 < 1.20, so that the sensitivity of the lens is reduced, and the imaging quality is improved.

A distance SAG42 between an intersection point of an image side surface of the fourth lens and the optical axis and an effective radius vertex of the image side surface of the fourth lens on the optical axis and a central thickness CT4 of the fourth lens on the optical axis may satisfy 0.2 < SAG42/CT4 < 0.6, and more specifically, SAG42 and CT4 may further satisfy 0.29 < SAG42/CT4 < 0.58. By reasonably configuring the SAG42 and the CT4, the sensitivity of the lens can be effectively reduced, and the imaging quality is improved.

The half of the diagonal length ImgH of the effective pixel area of the photosensitive element on the imaging surface of the camera lens and the total effective focal length f of the camera lens meet the condition that ImgH/f is more than 1, more specifically, ImgH and f further meet the condition that ImgH/f is more than or equal to 1.10 and less than or equal to 1.13, so that the photosensitive element can image a larger object side space.

Optionally, the camera lens may further include a filter disposed between the fourth lens element and the image plane, where the filter may be a bandpass filter, and the bandpass wavelength of the filter may be about 400nm to about 800 nm. The filter can be used for filtering the unnecessary spectral range, thereby improving the imaging quality of the lens.

Optionally, the above-described imaging lens may further include a protective glass for protecting the photosensitive element located on the imaging surface.

Alternatively, in order to satisfy the requirement of light weight, a plastic lens may be used for each lens in the above-described imaging lens.

The camera lens adopts four lenses, for example, so that the problems of overlarge size and overweight of the lens caused by the overlarge number of the lenses can be effectively avoided, and the miniaturization and the lightweight of the lens are favorably realized. By reasonably distributing the focal power and the surface type of each lens, the central thickness of each lens, the on-axis distance between each lens and the like, the camera lens according to the embodiment of the application can realize the expansion of the field angle of the lens, the shortening of the total optical length of the lens and the reduction of the sensitivity of the lens while ensuring the imaging quality, thereby providing the wide-angle camera lens which is applicable to portable equipment, has compact structure, high image quality and low sensitivity.

In the embodiment of the present application, at least one of the mirror surfaces of each lens is an aspherical mirror surface. The aspheric lens is characterized in that: the curvature varies continuously from the center to the periphery of the lens. Unlike a spherical lens having a constant curvature from the center to the periphery of the lens, an aspherical lens has a better curvature radius characteristic, and has advantages of improving distortion aberration and improving astigmatic aberration. After the aspheric lens is adopted, the aberration generated in imaging can be eliminated as much as possible, so that the imaging quality of the camera lens is improved.

However, it will be appreciated by those skilled in the art that the number of lenses constituting an imaging lens may be varied to achieve the various results and advantages described in this specification without departing from the claimed subject matter. For example, although four lenses are exemplified in the embodiment, the imaging lens is not limited to including four lenses. The camera lens may also include other numbers of lenses, if desired.

Specific examples of an imaging lens applicable to the above-described embodiments are further described below with reference to the drawings.

Example 1

An imaging lens according to embodiment 1 of the present application is described below with reference to fig. 1 to 2C. Fig. 1 shows a schematic configuration diagram of an imaging lens according to embodiment 1 of the present application.

As shown in fig. 1, the imaging lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and an image plane S11. The image pickup lens may further include a photosensitive element provided to the image formation surface S11.

The first lens L1 has positive power, the object-side surface S1 is convex, the image-side surface S2 is concave, and both the object-side surface S1 and the image-side surface S2 of the first lens L1 are aspheric.

The second lens L2 has positive power, the object-side surface S3 is concave, the image-side surface S4 is convex, and both the object-side surface S3 and the image-side surface S4 of the second lens L2 are aspheric.

The third lens L3 has positive power, the object-side surface S5 is concave, the image-side surface S6 is convex, and both the object-side surface S5 and the image-side surface S6 of the third lens L3 are aspheric.

The fourth lens L4 has positive power, and has a convex object-side surface S7 and a concave image-side surface S8, and both the object-side surface S7 and the image-side surface S8 of the fourth lens L4 are aspheric.

Alternatively, the imaging lens may further include a filter L5 having an object side surface S9 and an image side surface S10. The filter L5 may be a bandpass filter, which may have a bandpass wavelength range of about 400nm to about 800 nm.

Alternatively, a stop STO for limiting the light beam may be provided between the first lens L1 and the second lens L2 to improve the imaging quality of the imaging lens.

Table 1 shows the surface type, radius of curvature, thickness, material, and conic coefficient of each lens of the imaging lens of example 1, where the unit of the radius of curvature and the thickness are both millimeters (mm).

TABLE 1

As can be seen from table 1, the radius of curvature R5 of the object-side surface S5 of the third lens L3 and the radius of curvature R6 of the image-side surface S6 of the third lens L3 satisfy the relationship of R5/R6 equal to 0.76.

In the present embodiment, each aspherical surface type x is defined by the following formula:

wherein x is the rise of the distance from the aspheric surface vertex to the aspheric surface vertex when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, and c is 1/R (i.e., paraxial curvature c is the reciprocal of radius of curvature R in table 1 above); k is the conic coefficient (given in table 1); ai is the correction coefficient of the i-th order of the aspheric surface. Table 2 below shows the high-order coefficient A of each of the aspherical mirror surfaces S1 to S8 used in example 1 ₄ 、A ₆ 、A ₈ 、A ₁₀ 、A ₁₂ 、A ₁₄ And A ₁₆ 。

Flour mark

A4

A6

A8

A10

A12

A14

A16

S1

2.9247E-02

1.5296E-02

-2.4691E-02

1.9903E-02

-1.4463E-04

-5.9714E-03

2.2840E-03

S2

1.1008E-01

-1.4043E-01

9.9462E-02

2.7193E-01

-7.8784E-01

7.8026E-01

-2.8649E-01

S3

-2.1330E-01

-2.3131E-01

-4.4516E-01

3.0224E-01

5.0344E-12

5.7851E-13

-5.3988E-13

S4

-4.8956E-02

3.2558E-01

-3.6404E-01

5.8302E-02

4.8752E-02

1.8133E-09

3.0810E-10

S5

1.2505E-01

-1.3994E-01

3.2332E-01

-1.6067E-01

-1.1485E-03

1.9611E-03

6.5385E-03

S6

-3.8901E-02

4.7375E-02

-9.1492E-02

5.0488E-02

9.3052E-04

8.3495E-05

6.9163E-05

S7

-2.0272E-01

6.4779E-02

-2.8490E-02

6.9829E-03

-6.7768E-04

1.3197E-05

-2.2037E-06

S8

-2.0575E-01

8.1546E-02

-3.5375E-02

1.0383E-02

-1.9585E-03

2.0925E-04

-9.5339E-06

TABLE 2

Table 3 below gives the total effective focal length f of the image pickup lens, the effective focal lengths f1 to f4 of the respective lenses, the total optical length TTL of the image pickup lens (i.e., the distance on the optical axis from the object side surface S1 of the first lens L1 to the imaging surface S11), half ImgH of the diagonal length of the effective pixel region of the light-sensitive element on the imaging surface S11 of the image pickup lens, the maximum half field angle HFOV of the image pickup lens, and the f-number Fno of the image pickup lens of embodiment 1.

Parameter(s)	f(mm)	f1(mm)	f2(mm)	f3(mm)	f4(mm)
						Numerical value	2.14	14.01	2.35	73.90	13.91
Parameter(s)	TTL(mm)	ImgH(mm)	HFOV(°)	Fno
						Numerical value	4.59	2.42	50.23	2.25

TABLE 3

As can be seen from table 3, f1/f2 ═ 5.97 is satisfied between the effective focal length f1 of the first lens L1 and the effective focal length f2 of the second lens L2; the ImgH/f between half of the diagonal length ImgH of the effective pixel area of the photosensitive element on the imaging surface S11 of the imaging lens and the total effective focal length f of the imaging lens satisfies 1.13. As can be seen from tables 1 and 3, the second lens L2 satisfies CT2/TTL being 0.15 between the central thickness CT2 on the optical axis and the total optical length TTL of the imaging lens; the first lens L1 and the second lens L2 satisfy (T12 x 10)/TTL 1.10 between the distance T12 apart on the optical axis and the total optical length TTL of the imaging lens.

In embodiment 1, ET4/CT4 of 1.09 is satisfied between the edge thickness ET4 of the fourth lens L4 and the central thickness CT4 of the fourth lens L4 on the optical axis; an effective radius DT12 of the image side surface S2 of the first lens L1 and an effective radius DT22 of the image side surface S4 of the second lens L2 meet the condition that DT12/DT22 is 0.99; an effective radius DT11 of an object side surface S1 of the first lens L1 and an effective radius DT32 of an image side surface S6 of the third lens L3 meet the condition that DT11/DT32 is 1.00; the axial distance SAG42 from the intersection point of the image side surface S8 of the fourth lens L4 and the optical axis to the effective radius vertex of the image side surface S8 of the fourth lens L4 and the central thickness CT4 of the fourth lens L4 on the optical axis satisfy SAG42/CT4 equal to 0.58.

In the present embodiment, the maximum half field angle HFOV of the imaging lens is 50.23 °, and has a large field range.

Fig. 2A shows on-axis chromatic aberration curves of the imaging lens of embodiment 1, which represent deviation of convergence focuses of light rays of different wavelengths after passing through the lens. Fig. 2B shows astigmatism curves representing meridional field curvature and sagittal field curvature of the imaging lens of embodiment 1. Fig. 2C shows a distortion curve of the imaging lens of embodiment 1, which represents the distortion magnitude values in the case of different angles of view. As can be seen from fig. 2A to 2C, the imaging lens according to embodiment 1 can achieve good imaging quality.

Example 2

An imaging lens according to embodiment 2 of the present application is described below with reference to fig. 3 to 4C. In this embodiment and the following embodiments, descriptions of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 3 shows a schematic configuration diagram of an imaging lens according to embodiment 2 of the present application.

As shown in fig. 3, the imaging lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and an image plane S11. The image pickup lens may further include a photosensitive element provided to the image formation surface S11.

The second lens L2 has positive power, the object-side surface S3 is convex, the image-side surface S4 is convex, and both the object-side surface S3 and the image-side surface S4 of the second lens L2 are aspheric.

Table 4 shows the surface type, radius of curvature, thickness, material, and conic coefficient of each lens of the imaging lens of example 2, where the unit of the radius of curvature and the thickness are both millimeters (mm). Table 5 shows high-order term coefficients that can be used for each aspherical mirror surface in example 2, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above. Table 6 shows the total effective focal length f of the imaging lens, the effective focal lengths f1 to f4 of the respective lenses, the total optical length TTL of the imaging lens, half ImgH of the diagonal length of the effective pixel region of the photosensitive element on the imaging surface S11 of the imaging lens, the maximum half field angle HFOV of the imaging lens, and the f-number Fno of the imaging lens of example 2.

TABLE 4

TABLE 5

Parameter(s)	f(mm)	f1(mm)	f2(mm)	f3(mm)	f4(mm)
						Numerical value	2.20	25.73	3.67	8.01	11.53
Parameter(s)	TTL(mm)	ImgH(mm)	HFOV(°)	Fno
						Numerical value	4.56	2.41	49.88	2.25

TABLE 6

Fig. 4A shows an on-axis chromatic aberration curve of the imaging lens of embodiment 2, which represents the deviation of the convergent focal points of light rays of different wavelengths after passing through the lens. Fig. 4B shows astigmatism curves representing meridional field curvature and sagittal field curvature of the imaging lens of embodiment 2. Fig. 4C shows a distortion curve of the imaging lens of embodiment 2, which represents the distortion magnitude values in the case of different angles of view. As can be seen from fig. 4A to 4C, the imaging lens according to embodiment 2 can achieve good imaging quality.

Example 3

An imaging lens according to embodiment 3 of the present application is described below with reference to fig. 5 to 6C. Fig. 5 shows a schematic configuration diagram of an imaging lens according to embodiment 3 of the present application.

As shown in fig. 5, the imaging lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and an image plane S11. The imaging lens may further include a photosensitive element provided on the imaging surface S11.

The third lens L3 has negative power, the object-side surface S5 is concave, the image-side surface S6 is convex, and both the object-side surface S5 and the image-side surface S6 of the third lens L3 are aspheric.

The fourth lens L4 has positive power, and has a convex object-side surface S7, a concave image-side surface S8, and both the object-side surface S7 and the image-side surface S8 of the fourth lens L4 are aspheric.

Alternatively, a stop STO for limiting the light flux may be provided between the first lens L1 and the second lens L2 to improve the imaging quality of the photographing lens.

Table 7 shows the surface type, radius of curvature, thickness, material, and conic coefficient of each lens of the imaging lens of example 3, where the unit of the radius of curvature and the thickness are both millimeters (mm). Table 8 shows high-order term coefficients that can be used for each aspherical mirror surface in example 3, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above. Table 9 shows the total effective focal length f of the imaging lens, the effective focal lengths f1 to f4 of the respective lenses, the total optical length TTL of the imaging lens, half ImgH of the diagonal length of the effective pixel region of the photosensitive element on the imaging surface S11 of the imaging lens, the maximum half field angle HFOV of the imaging lens, and the f-number Fno of the imaging lens in example 3.

TABLE 7

TABLE 8

Parameter(s)	f(mm)	f1(mm)	f2(mm)	f3(mm)	f4(mm)
						Numerical value	2.15	11.65	1.94	-8.12	13.67
Parameter(s)	TTL(mm)	ImgH(mm)	HFOV(°)	Fno
						Numerical value	4.62	2.41	50.52	2.25

TABLE 9

Fig. 6A shows an on-axis chromatic aberration curve of the imaging lens of embodiment 3, which represents the deviation of the convergent focal points of light rays of different wavelengths after passing through the lens. Fig. 6B shows astigmatism curves representing meridional field curvature and sagittal field curvature of the imaging lens of embodiment 3. Fig. 6C shows a distortion curve of the imaging lens of embodiment 3, which represents the distortion magnitude values in the case of different angles of view. As can be seen from fig. 6A to 6C, the imaging lens system according to embodiment 3 can achieve good imaging quality.

Example 4

An imaging lens according to embodiment 4 of the present application is described below with reference to fig. 7 to 8C. Fig. 7 shows a schematic configuration diagram of an imaging lens according to embodiment 4 of the present application.

As shown in fig. 7, the imaging lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and an image plane S11. The image pickup lens may further include a photosensitive element provided to the image formation surface S11.

The second lens L2 has positive power, and has a concave object-side surface S3, a convex image-side surface S4, and both the object-side surface S3 and the image-side surface S4 of the second lens L2 are aspheric.

The fourth lens L4 has negative power, and has a convex object-side surface S7 and a concave image-side surface S8, and both the object-side surface S7 and the image-side surface S8 of the fourth lens L4 are aspheric.

Table 10 shows the surface type, radius of curvature, thickness, material, and conic coefficient of each lens of the imaging lens of example 4, where the unit of the radius of curvature and the thickness are both millimeters (mm). Table 11 shows high-order term coefficients that can be used for each aspherical mirror surface in example 4, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above. Table 12 shows the total effective focal length f of the imaging lens, the effective focal lengths f1 to f4 of the respective lenses, the total optical length TTL of the imaging lens, half ImgH of the diagonal length of the effective pixel region of the photosensitive element on the imaging surface S11 of the imaging lens, the maximum half field angle HFOV of the imaging lens, and the f-number Fno of the imaging lens of example 4.

Watch 10

TABLE 11

Parameter(s)	f(mm)	f1(mm)	f2(mm)	f3(mm)	f4(mm)
						Numerical value	2.20	14.72	2.60	4.29	-5.16
Parameter(s)	TTL(mm)	ImgH(mm)	HFOV(°)	Fno
						Numerical value	5.01	2.41	49.96	2.25

TABLE 12

Fig. 8A shows on-axis chromatic aberration curves of the imaging lens of embodiment 4, which represent deviation of convergence focuses of light rays of different wavelengths after passing through the lens. Fig. 8B shows astigmatism curves representing meridional field curvature and sagittal field curvature of the imaging lens of embodiment 4. Fig. 8C shows a distortion curve of the imaging lens of embodiment 4, which represents distortion magnitude values in the case of different angles of view. As can be seen from fig. 8A to 8C, the imaging lens according to embodiment 4 can achieve good imaging quality.

In conclusion, examples 1 to 4 each satisfy the relationship shown in table 13 below.

Conditional formula (I)	1	2	3	4
					ImgH/f	1.13	1.10	1.12	1.10
f1/f2	5.97	7.00	6.01	5.66
					R5/R6	0.76	1.00	0.72	1.14
CT2/TTL	0.15	0.18	0.21	0.14
					(T12*10)/TTL	1.10	0.81	1.37	1.49
ET4/CT4	1.09	1.08	1.09	1.36
					DT12/DT22	0.99	0.78	1.24	1.27
DT11/DT32	1.00	1.02	1.20	1.11
					SAG42/CT4	0.58	0.32	0.29	0.38

Watch 13

The present application also provides an image pickup apparatus, wherein the electronic photosensitive element may be a photosensitive coupling element (CCD) or a Complementary Metal Oxide Semiconductor (CMOS). The camera device may be a stand-alone camera device such as a digital camera, or may be a camera module integrated on a mobile electronic device such as a mobile phone. The image pickup apparatus is equipped with the image pickup lens described above.

The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.

Claims

1. The image pickup lens sequentially comprises from an object side to an image side along an optical axis: a first lens, a second lens, a third lens and a fourth lens having optical power,

the first lens and the second lens each have a positive optical power;

the object side surface of the third lens and the image side surface of the fourth lens are both concave surfaces, and the image side surface of the fourth lens is provided with at least one point of inflection;

the half of the diagonal length of an effective pixel area on an imaging surface of the camera lens, ImgH, and the total effective focal length f of the camera lens meet the condition that ImgH/f is more than 1, and the effective focal length f1 of the first lens and the effective focal length f2 of the second lens meet the condition that f1/f2 is less than or equal to 7; and

the number of the lenses having focal power of the imaging lens is four.

2. The imaging lens of claim 1, wherein a radius of curvature R5 of the object-side surface of the third lens and a radius of curvature R6 of the image-side surface of the third lens satisfy 0.7 < R5/R6 < 1.2.

3. The imaging lens according to claim 1, characterized in that the imaging lens further comprises a diaphragm provided between the first lens and the second lens.

4. The imaging lens assembly of claim 3, wherein the object-side surface of the first lens element is convex and the image-side surface of the second lens element is convex.

5. The imaging lens of claim 1, wherein a central thickness CT2 of the second lens element on the optical axis and a distance TTL between a center of an object-side surface of the first lens element and the optical axis of an imaging surface of the imaging lens satisfy 0.1 < CT2/TTL < 0.22.

6. The imaging lens system according to claim 4, wherein a distance T12 between the first lens element and the second lens element on the optical axis and a distance TTL between a center of an object side surface of the first lens element and the optical axis of an image plane of the imaging lens system satisfy 0.8 < (T12 x 10)/TTL < 1.5.

7. The imaging lens of claim 1, wherein an edge thickness ET4 of the fourth lens element and a center thickness CT4 of the fourth lens element on the optical axis satisfy 1 < ET4/CT4 < 1.5.

8. The imaging lens according to claim 4, wherein an effective radius DT12 of the image side surface of the first lens and an effective radius DT22 of the image side surface of the second lens satisfy 0.7 < DT12/DT22 < 1.3.

9. The imaging lens according to claim 4, wherein an effective radius DT11 of the object-side surface of the first lens and an effective radius DT32 of the image-side surface of the third lens satisfy 0.9 < DT11/DT32 < 1.3.

10. The imaging lens of claim 1, wherein a distance SAG42 on the optical axis from an intersection of the fourth lens image-side surface and the optical axis to an effective radius vertex of the fourth lens image-side surface and a central thickness CT4 on the optical axis of the fourth lens satisfy 0.2 < SAG42/CT4 < 0.6.

11. The imaging lens according to any one of claims 1 to 10, further comprising a bandpass filter provided between the fourth lens and the imaging surface of the imaging lens, the bandpass filter having a bandpass wavelength range of 400nm to 800 nm.

12. The image pickup lens sequentially comprises from an object side to an image side along an optical axis: a first lens, a second lens, a third lens, and a fourth lens,

the first lens and the second lens each have a positive optical power;

at least one of the third lens and the fourth lens has positive focal power, the object-side surface of the third lens is a concave surface, and the image-side surface of the fourth lens is a concave surface and has at least one point of inflection;

the edge thickness ET4 of the fourth lens and the central thickness CT4 of the fourth lens on the optical axis satisfy 1 < ET4/CT4 < 1.5, and the effective focal length f1 of the first lens and the effective focal length f2 of the second lens satisfy 3 < f1/f2 < 7; and

the number of the lenses having focal power of the imaging lens is four.

13. The imaging lens assembly of claim 12, wherein the object-side surface of the first lens element is convex, the image-side surface of the second lens element is convex,

the camera lens further comprises a diaphragm arranged between the first lens and the second lens.

14. The imaging lens of claim 12, wherein a radius of curvature R5 of the object-side surface of the third lens and a radius of curvature R6 of the image-side surface of the third lens satisfy 0.7 < R5/R6 < 1.2.

15. The image capturing lens assembly of claim 12, wherein the thickness CT2 of the second lens element along the optical axis and the distance TTL between the center of the object-side surface of the first lens element and the optical axis of the image capturing lens assembly satisfy 0.1 < CT2/TTL < 0.22.

16. The imaging lens of claim 13, further comprising a bandpass filter disposed between the fourth lens and the imaging surface of the imaging lens.

17. The imaging lens of claim 16, wherein the bandpass wavelength range of the bandpass filter is 400nm to 800 nm.

18. The imaging lens according to claim 13, wherein ImgH > 1 is satisfied by half the diagonal length of an effective pixel region on an imaging surface of the imaging lens and a total effective focal length f of the imaging lens.

19. An image-taking lens according to claim 12, 13 or 16, wherein the first lens element and the second lens element are spaced apart from each other on the optical axis by a distance T12, and a distance TTL between a center of an object-side surface of the first lens element and an image-forming surface of the image-taking lens on the optical axis satisfies 0.8 < (T12 x 10)/TTL < 1.5.

20. The imaging lens assembly according to claim 19, wherein an effective radius DT12 of the image side surface of the first lens and an effective radius DT22 of the image side surface of the second lens satisfy 0.7 < DT12/DT22 < 1.3.

21. The imaging lens of claim 19, wherein an effective radius DT11 of the object-side surface of the first lens and an effective radius DT32 of the image-side surface of the third lens satisfy 0.9 < DT11/DT32 < 1.3.

22. The imaging lens of claim 19, wherein a distance SAG42 on the optical axis from an intersection point of the fourth lens image-side surface and the optical axis to an effective radius vertex of the fourth lens image-side surface and a center thickness CT4 on the optical axis of the fourth lens satisfy 0.2 < SAG42/CT4 < 0.6.